WO2012025999A1 - トルク検出装置 - Google Patents
トルク検出装置 Download PDFInfo
- Publication number
- WO2012025999A1 WO2012025999A1 PCT/JP2010/064333 JP2010064333W WO2012025999A1 WO 2012025999 A1 WO2012025999 A1 WO 2012025999A1 JP 2010064333 W JP2010064333 W JP 2010064333W WO 2012025999 A1 WO2012025999 A1 WO 2012025999A1
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- WIPO (PCT)
- Prior art keywords
- excitation
- line
- disconnection
- resolver
- coil
- Prior art date
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
- B62D5/049—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures detecting sensor failures
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
- B62D6/08—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque
- B62D6/10—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque characterised by means for sensing or determining torque
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
- G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
- G01L3/101—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means
- G01L3/105—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means involving inductive means
Definitions
- the present invention relates to a torque detector that includes two resolvers and detects torque acting on a shaft based on a rotation angle detected by each resolver.
- an electric power steering device that applies a steering assist torque to a driver's steering operation.
- the electric power steering device detects a steering torque acting on the steering shaft by a torque detection device, calculates a target assist torque that increases as the steering torque increases, and obtains the calculated target assist torque. Feedback control of the energization amount. Therefore, in the electric power steering device, the reliability of the torque detection device is particularly required.
- the steering torque detection device calculates a steering torque proportional to the torsion angle by detecting the torsion angle of the torsion bar provided on the steering shaft.
- the torque detection device disclosed in Japanese Patent Application Laid-Open No. 2003-315182 employs a configuration that detects the twist angle of a torsion bar using two resolvers.
- a first resolver is provided on one end side of the torsion bar and a second resolver is provided on the other end side, and the rotation angle ( ⁇ 1 ) detected by the first resolver and the second resolver are detected.
- the steering torque is detected from the difference from the rotation angle ( ⁇ 2 ).
- Each resolver includes an excitation coil that is supplied with an excitation AC signal and energizes the rotor coil, and a pair of detection coils that are fixed around the torsion bar.
- the pair of detection coils are assembled with an electrical angle shifted by 90 degrees ( ⁇ / 2).
- One of the detection coils outputs an AC signal having an amplitude corresponding to the sin value of the rotation angle of the rotor, and the other of the detection coils outputs an AC signal having an amplitude corresponding to the cos value of the rotation angle of the rotor.
- the two resolvers are connected to the ECU constituting the torque calculation unit.
- the ECU supplies an AC signal for excitation by connecting a common excitation line to each end of the excitation coil of the first resolver and the excitation coil of the second resolver.
- the ECU connects an independent detection line to one end of each detection coil of the first resolver, inputs a sin value detection signal and a cos value detection signal, and is independent to one end of each detection coil of the second resolver.
- the detected detection line is connected and a sin value detection signal and a cos value detection signal are input.
- the other ends of the excitation coil and the detection coil are connected to the ECU through a common ground line.
- the ECU calculates the rotation angle of the torsion bar at the position where each resolver is provided from the output signals of the pair of detection coils in each resolver. Then, the steering torque acting on the torsion bar is detected from the difference between the two rotation angles.
- the present invention has been made to cope with the above problem, and improves the reliability against disconnection without increasing the number of wirings connecting the ECU (torque calculation unit) and the first resolver and the second resolver as much as possible. For the purpose.
- the torque detector of the present invention is characterized in that a first excitation coil is supplied with an excitation AC signal and outputs a detection signal corresponding to the rotation angle of the shaft in the first axial direction position.
- a resolver unit having a resolver, and a second resolver that outputs a detection signal corresponding to a rotation angle of the shaft in a second axial position when an excitation AC signal is supplied to a second excitation coil; Connected via a wire harness to supply excitation AC signals to the first excitation coil and the second excitation coil, and input detection signals output from the first resolver and the second resolver, respectively.
- a first rotation angle at the first axial position and a second rotation angle at the second axial position of the shaft are calculated, and the calculated first rotation angle and second And a torque calculation unit that calculates a torque acting in a direction around the axis of the shaft based on a rotation angle.
- the torque calculation unit includes a first excitation line for the first excitation coil.
- the excitation AC signal is supplied via the second excitation coil, and the excitation AC signal is supplied to the second excitation coil via a second excitation line different from the first excitation line.
- An electrical resistance element for electrically connecting the first excitation line and the second excitation line is provided.
- the torque detection device of the present invention includes a resolver unit and a torque calculation unit.
- the resolver unit and the torque calculation unit are electrically connected to each other via a wire harness.
- the resolver unit detects a rotation angle (first rotation angle) at a first axial position of the shaft and a rotation angle (second rotation angle) at a second axial position of the shaft.
- the second resolver In the first resolver, the excitation AC signal output from the torque calculator is supplied to the first excitation coil. This AC signal for excitation is supplied to the first excitation coil via the first excitation line. Accordingly, the first resolver outputs a detection signal having an amplitude corresponding to the first rotation angle from the detection coils of a plurality of phases.
- the first resolver includes a sin phase detection coil and a cos phase detection coil, and outputs an AC voltage whose amplitude increases or decreases as a detection signal depending on the sin value of the first rotation angle from the sin phase detection coil.
- An AC voltage whose amplitude increases or decreases depending on the cos value of the first rotation angle is output as a detection signal from the phase detection coil.
- the excitation AC signal output from the torque calculation unit is supplied to the second excitation coil.
- This excitation AC signal is supplied to the second excitation coil via a second excitation line different from the first excitation line.
- the second resolver outputs a detection signal having an amplitude corresponding to the second rotation angle from the plurality of phase detection coils.
- the second resolver includes a sin phase detection coil and a cos phase detection coil, and outputs an AC voltage whose amplitude increases or decreases as a detection signal depending on the sin value of the second rotation angle from the sin phase detection coil.
- An AC voltage whose amplitude increases or decreases depending on the cos value of the second rotation angle is output as a detection signal from the phase detection coil.
- the first resolver and the second resolver are configured such that the excitation AC signal is supplied to the first excitation coil and the second excitation coil via the independent first excitation line and second excitation line, respectively. Has been. Further, the first excitation line and the second excitation line are connected to each other via an electric resistance element in the resolver unit.
- the torque calculator receives detection signals output from the first resolver and the second resolver, calculates a first rotation angle and a second rotation angle based on the input detection signals, and calculates the calculated first rotation angle and Based on the second rotation angle, a torque acting in the direction around the shaft axis is obtained by calculation.
- the resolver unit and the torque calculation unit are electrically connected to each other via a wire harness.
- the first excitation line included in the wire harness is disconnected, only the second excitation line is used for the resolver unit.
- An excitation AC signal is supplied.
- An excitation AC signal is supplied from the second excitation line to the second excitation coil.
- the first excitation coil is not supplied with an excitation AC signal from the first excitation line, but the first excitation line and the second excitation line are connected to each other via an electric resistance element in the resolver unit.
- An excitation AC signal is supplied to the excitation coil from the second excitation line via an electric resistance element.
- the current flowing through the first exciting coil varies with respect to the normal time (when the wire is not disconnected), and accordingly, the voltage of the detection signal output from the first resolver also varies.
- the calculation of the first rotation angle is not affected. Therefore, even when the first excitation line is disconnected, the first rotation angle can be calculated.
- the excitation AC signal is supplied to the resolver unit using only the first excitation line.
- An excitation AC signal is supplied to the first excitation coil from the first excitation line.
- An excitation AC signal is supplied to the second excitation coil from the first excitation line via an electric resistance element.
- the current flowing through the second exciting coil varies with respect to the normal time (when no disconnection occurs), and accordingly, the voltage of the detection signal output from the second resolver also varies.
- the second rotation angle can be calculated even when the second excitation line is disconnected.
- the excitation line is provided independently for each resolver, and the electrical resistance element is provided between the two excitation lines, so that the disconnection can be achieved at a low cost without a significant increase in the configuration.
- the reliability with respect to can be improved.
- the first excitation coil includes the first excitation line connected to one end of the first excitation coil and the common ground line connected to the other end of the first excitation coil.
- the second excitation coil is connected to the calculation unit, and the torque is calculated by the second excitation line connected to one end of the second excitation coil and the common ground line connected to the other end of the second excitation coil.
- the torque calculation unit includes an anti-phase coil drive circuit that separately outputs excitation AC signals having the same frequency and opposite phases to the first excitation line and the second excitation line. Be prepared.
- the antiphase torque drive circuit separately outputs the excitation AC signals to the first excitation line and the second excitation line.
- an excitation AC voltage is applied between the first excitation line and the common ground line, and an AC current flows through the first excitation coil.
- an excitation AC voltage is applied between the second excitation line and the common ground line, and an AC current flows through the second excitation coil.
- This common ground line may be grounded so as to have the same potential as the ground of the power supply device, but it is not always necessary to do so, and an excitation AC voltage is generated between the excitation line and the common ground line. Thus, it is sufficient to set the potential to be the center of the amplitude of the excitation AC signal.
- the excitation AC signal output from the antiphase coil drive circuit to the first excitation line and the excitation AC signal output from the antiphase coil drive circuit to the second excitation line have the same frequency and opposite phases. It is set to be.
- the first excitation coil and the second excitation coil can be driven in the same manner as normal (when the common ground line is not disconnected).
- a 1st rotation angle and a 2nd rotation angle can be calculated appropriately, and a torque is detected from these two rotation angles. be able to.
- the anti-phase coil drive circuit it is not always necessary to reverse the excitation AC signal output to the first excitation line and the excitation AC signal output to the second excitation line, and the common ground line is disconnected.
- the configuration may be such that the phase is reversed only when the
- Another feature of the present invention is based on a first excitation line disconnection detecting means for detecting disconnection of the first excitation line based on a detection signal output from the first resolver, and a detection signal output from the second resolver.
- a second excitation line disconnection detecting means for detecting disconnection of the second excitation line, and when the disconnection of the first excitation line is detected, the sign of the calculated first rotation angle is inverted, and the first Rotation angle correction means for inverting the sign of the calculated second rotation angle when disconnection of two excitation lines is detected.
- the excitation AC signal is supplied from the second excitation line to the first excitation coil via the electric resistance element, so that the current flowing through the first excitation coil is normal.
- the voltage of the detection signal output from the first resolver also changes compared to the normal time.
- the first excitation line disconnection detecting means detects disconnection of the first excitation line based on the voltage of the detection signal output from the first resolver.
- the second excitation line disconnection detecting means detects disconnection of the second excitation line based on the voltage of the detection signal output from the second resolver.
- the rotation angle correction means reverses the sign (positive / negative) of the first rotation angle when the disconnection of the first excitation line is detected, and when the disconnection of the second excitation line is detected, Inverts the sign of two rotation angles. Thereby, even when the excitation line is disconnected, the rotation angle can be calculated appropriately.
- phase lag correction means for correcting the phase lag of the detection signal output from the second resolver is provided.
- the excitation AC signal when the first excitation line is disconnected, the excitation AC signal is supplied from the second excitation line to the first excitation coil via the electric resistance element, so that the phase of the detection signal output from the first resolver
- the amount of delay changes.
- the excitation AC signal is supplied from the first excitation line to the second excitation coil via the electric resistance element, so that the phase delay amount of the detection signal output from the second resolver is reduced.
- the phase delay amount correcting means corrects the phase delay amount of the detection signal output from the first resolver when the disconnection of the first excitation line is detected, and the disconnection of the second excitation line is detected. If so, the phase delay amount of the detection signal output from the second resolver is corrected. Thereby, the rotation angle when the excitation line is disconnected can be calculated more accurately.
- Another feature of the present invention is that an inductor is connected in series to the electric resistance element, and the phase delay amount of the detection signal output from the first resolver when the first excitation line or the second excitation line is disconnected or the This is because the phase delay amount of the detection signal output from the second resolver is not changed.
- an electric resistance element and an inductor are connected in series between the first excitation line and the second excitation line. Therefore, when the first excitation line or the second excitation line is disconnected, the excitation AC signal is supplied to the first excitation coil or the second excitation coil via the electric resistance element and the inductor. For this reason, by adjusting the inductance of the inductor in advance, the phase delay amount of the detection signal output from the resolver can be prevented from changing even when one of the excitation lines is disconnected. Thereby, the rotation angle when the excitation line is disconnected can be calculated more accurately.
- Another feature of the present invention is that it is provided with excitation line disconnection notification means for notifying abnormality when the disconnection of the first excitation line or the disconnection of the second excitation line is detected.
- the excitation line disconnection notification means performs abnormality notification when the disconnection of the first excitation line or the disconnection of the second excitation line is detected. This can prompt the user to repair. Therefore, the occurrence of a double failure can be suppressed and the reliability is improved.
- Another feature of the present invention is that one of the first excitation line or the second excitation line is set to the same potential as the set potential of the common ground line, and the first resolver or the second resolver in that state is set.
- a ground line disconnection detection unit that detects disconnection of the common ground line based on a detection signal, and a ground line disconnection notification unit that notifies abnormality when the disconnection of the common ground line is detected. is there.
- the present invention since the first excitation coil and the second excitation coil are driven by the excitation AC signal output from the antiphase coil drive circuit, even when the common ground line is disconnected, The first excitation coil and the second excitation coil can be driven in the same manner as normal (when the common ground line is not disconnected). However, if it continues to be used as it is, the torque cannot be detected when even a normal excitation line is disconnected, that is, when a double failure occurs. Therefore, the present invention includes ground line disconnection detection means for detecting disconnection of the common ground line, and ground line disconnection notification means for notifying abnormality when the disconnection of the common ground line is detected.
- the ground line disconnection detecting means sets one of the first excitation line and the second excitation line to the same potential as the set potential of the common ground line. For example, when the common ground line is grounded, the potential of one of the first excitation line or the second excitation line is fixed to zero volts. In this case, if the common ground line is not disconnected, the potential difference between the common ground line and the first excitation line or between the common ground line and the second excitation line becomes zero volts. Alternatively, no current flows through the second exciting coil. Therefore, the first resolver or the second resolver does not output a detection signal.
- the ground line disconnection detecting means sets one of the first excitation line and the second excitation line to the same potential as the set potential of the common ground line, and the first resolver or the second resolver in that state is set.
- the disconnection of the common ground line is detected based on the voltage of the detection signal.
- the ground line disconnection notification unit notifies the abnormality. This can prompt the user to repair. Therefore, the occurrence of a double failure can be suppressed and the reliability is improved.
- Another feature of the present invention is that one of the first excitation line or the second excitation line is opened by the torque calculation unit, and the electric rotation is based on the first rotation angle or the second rotation angle calculated in that state.
- a resistance disconnection detecting means for detecting disconnection of the resistance element
- a resistance disconnection notification means for informing the abnormality when the disconnection of the electric resistance element is detected.
- the present invention includes a resistance disconnection detecting unit that detects disconnection of the electrical resistance element, and a resistance disconnection notification unit that notifies abnormality when the disconnection of the electrical resistance element is detected.
- the resistance disconnection detecting means opens one of the first excitation line and the second excitation line with the torque calculation unit. That is, it is set to the same state as the state where the first excitation line or the second excitation line is disconnected. In this case, if the electric resistance element is not disconnected, an appropriate first rotation angle or second rotation angle can be calculated. On the other hand, when the electrical resistance element is disconnected, the first excitation coil or the second excitation coil cannot be properly energized, and therefore the appropriate first rotation angle or second rotation angle cannot be calculated.
- the resistance disconnection detecting means detects disconnection of the electrical resistance element based on the first rotation angle or the second rotation angle calculated in a state where one of the first excitation line or the second excitation line is opened by the torque calculation unit. To do. For example, when the rotation angle in the state where one of the first excitation line or the second excitation line is not opened is compared with the rotation angle in the opened state, It is determined that the resistance element is disconnected. Then, when the disconnection of the electrical resistance element is detected, the resistance disconnection notification means performs an abnormality notification. This can prompt the user to repair. Therefore, the occurrence of a double failure can be suppressed and the reliability is improved.
- FIG. 1 is a schematic configuration diagram of an electric power steering apparatus including a torque detection device according to an embodiment.
- FIG. 2 is an electric circuit diagram showing the configuration of the resolver unit and the connection between the resolver unit and the assist ECU.
- FIG. 3 is an equivalent circuit diagram of the resolver unit.
- FIG. 4 is an electric circuit diagram showing disconnection of the first excitation line.
- FIG. 5 is an electric circuit diagram showing disconnection of the second excitation line.
- FIG. 6 is an electric circuit diagram showing disconnection of the ground line.
- FIG. 7 is a flowchart showing a steering torque detection routine.
- FIG. 8 is a flowchart showing a ground disconnection detection subroutine.
- FIG. 9 is a flowchart showing a resistance disconnection detection subroutine.
- FIG. 1 is a schematic configuration diagram of an electric power steering apparatus including a torque detection device according to an embodiment.
- FIG. 2 is an electric circuit diagram showing the configuration of the resolver unit and the connection between the resolver unit and the assist ECU
- FIG. 10 is a flowchart showing a disconnection abnormality processing routine.
- FIG. 11 is a flowchart showing an excitation signal control routine according to the first modification.
- FIG. 12 is a flowchart illustrating a phase delay amount switching routine according to the second modification.
- FIG. 13 is an electric circuit diagram in which an inductor according to Modification 3 is added.
- FIG. 14 is an electric circuit diagram illustrating a configuration of a resolver unit according to a conventional example and a connection between the resolver unit and the assist ECU.
- FIG. 1 is a schematic configuration diagram of an electric power steering apparatus including a torque detection device as an embodiment.
- the electric power steering device for a vehicle includes a steering mechanism 10 that steers left and right front wheels FW1 and FW that are steered wheels by steering a steering handle 11, and a power assist unit 20 that is provided in the steering mechanism 10 and generates steering assist torque.
- an assist control device 50 (hereinafter referred to as an assist ECU 50) for driving and controlling the electric motor 21 of the power assist unit 20, a vehicle speed sensor 60, and a resolver unit 100.
- the steering mechanism 10 includes a steering shaft 12 connected to the steering handle 11 so as to rotate integrally with an upper end thereof, and a pinion gear 13 is connected to the lower end of the steering shaft 12 so as to rotate integrally.
- the pinion gear 13 meshes with rack teeth formed on the rack bar 14 to constitute a rack and pinion mechanism.
- Left and right front wheels FW1, FW2 are connected to both ends of the rack bar 14 via a tie rod and a knuckle arm (not shown) so as to be steerable.
- the left and right front wheels FW1 and FW2 are steered to the left and right according to the axial displacement of the rack bar 14 as the steering shaft 12 rotates about the axis.
- the power assist unit 20 is assembled to the rack bar 14.
- the power assist unit 20 includes a steering assist electric motor 21 (for example, a three-phase DC brushless motor) and a ball screw mechanism 22.
- the rotating shaft of the electric motor 21 is connected to the rack bar 14 through the ball screw mechanism 22 so as to be able to transmit power, and assists the steering of the left and right front wheels FW1, FW2 by the rotation.
- the ball screw mechanism 22 functions as a speed reducer and a rotation-linear converter, and decelerates the rotation of the electric motor 21 and converts it into a linear motion and transmits it to the rack bar 14.
- the electric motor 21 is provided with a rotation angle sensor 61 for detecting the rotation angle of the rotation shaft.
- the rotation angle sensor 61 is connected to the assist ECU 50.
- the steering shaft 12 is provided with a torsion bar 12a at an intermediate position in the axial direction.
- a portion connecting the upper end of the torsion bar 12a and the steering handle 11 is called an input shaft 12in, and a portion connecting the lower end of the torsion bar 12a and the pinion gear 13 is called an output shaft 12out.
- a resolver unit 100 is provided on the steering shaft 12.
- the resolver unit 100 includes a torsion bar 12a, a first resolver 110 assembled to the input shaft 12in, and a second resolver 120 assembled to the output shaft 12out.
- the first resolver 110 outputs a signal corresponding to the rotation angle of the input shaft 12in (the rotation angle at the one end position of the torsion bar 12a and corresponding to the rotation angle at the first axial position of the present invention).
- the two resolver 120 outputs a signal corresponding to the rotation angle of the output shaft 12out (the rotation angle at the other end position of the torsion bar 12a and corresponding to the rotation angle at the second axial position of the present invention).
- the steering handle 11 When the steering handle 11 is turned, torque acts on the steering shaft 12 and the torsion bar 12a is twisted.
- the torsion angle of the torsion bar 12a is proportional to the steering torque acting on the steering shaft 12. Therefore, the steering torque acting on the steering shaft 12 can be detected by obtaining the difference between the rotation angle ⁇ 1 detected by the first resolver 110 and the rotation angle ⁇ 2 detected by the second resolver 120.
- the first resolver 110 and the second resolver 120 are connected to the assist ECU 50.
- the assist ECU 50 includes a calculation unit 30 including a microcomputer, a signal processing circuit, and the like, and a motor drive circuit 40 (for example, a three-phase inverter circuit) configured by a switching circuit.
- the calculation unit 30 includes an assist calculation unit 31 and a torque calculation unit 32.
- the torque calculator 32 is connected to the resolver unit 100 and detects the steering torque acting on the steering shaft 12 by calculation.
- a configuration including the resolver unit 100 and the torque calculation unit 32 corresponds to the torque detection device of the present invention.
- the resolver unit 100 and the torque calculation unit 32 will be described later.
- the motor drive circuit 40 receives the PWM control signal from the assist calculation unit 31 and controls the duty ratio of the internal switching element to adjust the energization amount to the electric motor 21.
- the motor drive circuit 40 is provided with a current sensor 41 that detects a current flowing through the electric motor 21.
- the assist calculation unit 31 is connected to a current sensor 41, a vehicle speed sensor 60, and a rotation angle sensor 61.
- the vehicle speed sensor 60 outputs a vehicle speed detection signal representing the vehicle speed vx.
- the assist calculation unit 31 inputs the calculation result of the steering torque calculated by the torque calculation unit 32.
- the assist calculation unit 31 is connected with a warning lamp 65 for notifying the driver of the abnormality, and turns on the warning lamp 65 when disconnection is detected, which will be described later.
- the assist calculation unit 31 acquires the vehicle speed vx detected by the vehicle speed sensor 60 and the steering torque Tr calculated by the torque calculation unit 32, and calculates the target assist torque based on the acquired vehicle speed vx and the steering torque Tr. To do.
- the target assist torque is set so as to increase as the steering torque Tr increases and to decrease as the vehicle speed vx increases with reference to an assist map (not shown).
- the assist calculation unit 31 calculates a target current required to generate the target assist torque, and calculates a PI control (proportional integral control) equation based on the deviation between the actual current detected by the current sensor 41 and the target current.
- the target command voltage is used to calculate, and a PWM control signal corresponding to the target command voltage is output to the motor drive circuit 40.
- the assist calculation unit 31 acquires the rotation angle (electrical angle) of the electric motor 21 detected by the rotation angle sensor 61, and the three-phase (U-phase, V-phase, W-phase) PWM control signal corresponding to the rotation angle.
- the three-phase drive voltage is applied to the electric motor 21 by generating
- a target current in a direction rotating in the same direction as the driver's steering direction flows through the electric motor 21 by current feedback control.
- the driver's steering operation is appropriately assisted by the torque generated by the electric motor 21.
- the steering torque Tr is detected with the following configuration.
- FIG. 2 shows a schematic circuit configuration of the resolver unit 100.
- the first resolver 110 includes an input shaft 12in as a rotor.
- a first excitation coil 111 wound along the circumferential direction of the rotor is fixedly provided on the stator on the outer peripheral side of the input shaft 12in.
- a first rotor coil 114 is fixedly provided on the input shaft 12in serving as a rotor.
- the first rotor coil 114 rotates as the rotor rotates.
- the first rotor coil 114 is electrically connected to the first excitation coil 111 in a non-contact manner via a transformer (not shown) provided in the rotor, and is energized by an AC voltage applied to the first excitation coil 111. Is done.
- a plurality of first rotor coils 114 are arranged at equiangular intervals so that the electrical angle is k times the mechanical rotation angle of the rotor in order to increase the resolution of the rotation angle. .
- the first resolver 110 includes a first sin phase detection coil 112 and a first cos phase detection coil 113 on the outer peripheral side of the input shaft 12in.
- the first sin phase detection coil 112 and the first cos phase detection coil 113 are arranged at positions where the electrical angles are shifted from each other by ⁇ / 2.
- the first sin phase detection coil 112 and the first cos phase detection coil 113 are arranged on the rotation plane of the first rotor coil 114, and output an AC voltage signal by the magnetic flux generated by the first rotor coil 114.
- the amplitude value of the AC voltage signal generated in the first sin phase detection coil 112 and the first cos phase detection coil 113 varies depending on the rotational position of the first sin phase detection coil 112 and the first cos phase detection coil 113 with respect to the first rotor coil 114. To do.
- the first sin phase detection coil 112 outputs an AC voltage signal having an amplitude corresponding to the sin value of the rotation angle of the input shaft 12in, and the first cos phase detection coil 113 sets the cos value of the rotation angle of the input shaft 12in.
- An AC voltage signal having a corresponding amplitude is output.
- first excitation coil 111 is connected to the first excitation signal output port 50pe1 of the assist ECU 50 via the first excitation line 210.
- first excitation line 210 is provided in the resolver unit 100 in order to distinguish between a portion provided in the resolver unit 100 and a harness portion wired between the resolver unit 100 and the assist ECU 50.
- the portion is referred to as an in-unit first excitation line 210a
- the harness portion provided between the resolver unit 100 and the assist ECU 50 is referred to as an out-unit first excitation line 210b.
- the first excitation line 210a inside the unit and the first excitation line 210b outside the unit are connected by a first excitation signal input port 100pe1.
- first sin phase detection coil 112 is connected to the first sin phase signal input port 50ps1 of the assist ECU 50 via the first sin phase detection line 212.
- One end of the first cos phase detection coil 113 is connected to the first cos phase signal input port 50pc1 of the assist ECU 50 via the first cos phase detection line 213.
- the first sin phase detection line 212 and the first cos phase detection line 213 will be described by distinguishing between a portion provided in the resolver unit 100 and a harness portion wired between the resolver unit 100 and the assist ECU 50.
- the portions provided in the resolver unit 100 are referred to as an in-unit first sin phase detection line 212a and an in-unit first cos phase detection line 213a, and a harness portion provided between the resolver unit 100 and the assist ECU 50 is referred to as an out-unit first sin phase.
- the detection line 212b is referred to as an out-unit first cos phase detection line 213b.
- the first sin phase detection line 212a within the unit and the first sin phase detection line 212b outside the unit are connected at the first sin phase signal output port 100ps1.
- the first cos phase detection line 213a within the unit and the first cos phase detection line 213b outside the unit are connected at the first cos phase signal output port 100pc1.
- the second resolver 120 includes an output shaft 12out as a rotor.
- a second excitation coil 121 wound along the circumferential direction of the rotor is fixedly provided on the stator on the outer peripheral side of the output shaft 12out.
- a second rotor coil 124 is fixedly provided on the output shaft 12out serving as a rotor.
- the second rotor coil 124 rotates as the rotor rotates.
- the second rotor coil 124 is electrically connected to the second excitation coil 121 in a non-contact manner via a transformer (not shown) provided in the rotor, and is energized by an AC voltage applied to the second excitation coil 121. Is done.
- a plurality of second rotor coils 124 are arranged at equiangular intervals so that the electrical angle is k times the mechanical rotation angle of the rotor in order to increase the resolution of the rotation angle. .
- the second resolver 120 includes a second sin phase detection coil 122 and a second cos phase detection coil 123 on the outer peripheral side of the output shaft 12out.
- the second sin phase detection coil 122 and the second cos phase detection coil 123 are arranged at positions where the electrical angles are shifted from each other by ⁇ / 2.
- the second sin phase detection coil 122 and the second cos phase detection coil 123 are arranged on the rotation plane of the second rotor coil 124 and output an alternating voltage signal by the magnetic flux generated by the second rotor coil 124.
- the amplitude value of the AC voltage signal generated in the second sin phase detection coil 122 and the second cos phase detection coil 123 varies depending on the rotational position of the second sin phase detection coil 122 and the second cos phase detection coil 123 with respect to the second rotor coil 124. To do.
- the second sin phase detection coil 122 outputs an AC voltage signal having an amplitude corresponding to the sin value of the rotation angle of the output shaft 12out, and the second cos phase detection coil 123 sets the cos value of the rotation angle of the output shaft 12out.
- An AC voltage signal having a corresponding amplitude is output.
- the second excitation line 220 is provided in the resolver unit 100 in order to distinguish between a portion provided in the resolver unit 100 and a harness portion wired between the resolver unit 100 and the assist ECU 50.
- the portion is referred to as an in-unit second excitation line 220a
- the harness portion provided between the resolver unit 100 and the assist ECU 50 is referred to as an out-unit second excitation line 220b.
- the second excitation line 220a inside the unit and the second excitation line 220b outside the unit are connected by the second excitation signal input port 100pe2.
- One end of the second sin phase detection coil 122 is connected to the second sin phase signal input port 50ps2 of the assist ECU 50 via the second sin phase detection line 222.
- One end of the second cos phase detection coil 123 is connected to the second cos phase signal input port 50pc2 of the assist ECU 50 via the second cos phase detection line 223.
- the second sin phase detection line 222 and the second cos phase detection line 223 will be described by distinguishing between a portion provided in the resolver unit 100 and a harness portion wired between the resolver unit 100 and the assist ECU 50.
- the portions provided in the resolver unit 100 are referred to as the in-unit second sin phase detection line 222a and the in-unit second cos phase detection line 223a, and the harness portion provided between the resolver unit 100 and the assist ECU 50 is defined as the second sin phase outside the unit.
- the detection line 222b and the out-unit second cos phase detection line 223b are called.
- the in-unit second sin phase detection line 222a and the out-unit second sin phase detection line 222b are connected at the second sin phase signal output port 100ps2.
- the in-unit second cos phase detection line 223a and the out-unit second cos phase detection line 223b are connected by a second cos phase signal output port 100pc2.
- first in-unit excitation line 210 a and the second in-unit excitation line 220 a are electrically connected via the electric resistance element 230. That is, one end (excitation signal input side) of the first excitation coil 111 and one end (excitation signal input side) of the second excitation coil 121 are electrically connected by the electric resistance element 230 in the casing of the resolver unit 100. .
- connection point between the first in-unit excitation line 210a and the electric resistance element 230 is referred to as a connection point Xa
- connection point between the second in-unit excitation line 220a and the electric resistance element 230 is referred to as a connection point Xb.
- the other end of the first excitation coil 111, the other end of the second excitation coil 121, the other end of the first sin phase detection coil 112, the other end of the first cos phase detection coil 113, the other end of the second sin phase detection coil 122, The other end of the second cos phase detection coil 123 is connected to the ground port 50pg of the assist ECU 50 via a common ground line 240.
- a common ground line 240 In order to distinguish the ground line 240 from a portion provided in the resolver unit 100 and a harness portion wired between the resolver unit 100 and the assist ECU 50, the portion provided in the resolver unit 100 is described.
- a harness portion provided between the resolver unit 100 and the assist ECU 50 is referred to as an in-unit ground line 240a, and is referred to as an out-unit ground line 240b.
- the unit internal ground line 240a and the unit external ground line 240b are connected by a ground port 100pg.
- the 2 sin phase detection line 222b, the unit outside second cos phase detection line 223b, and the unit outside ground line 240b are bundled to form a wire harness.
- resolver unit 100 shown in FIG. 2 is represented by an equivalent circuit as shown in FIG.
- the assist ECU 50 includes a coil drive circuit 52.
- the coil drive circuit 52 includes a first excitation coil drive circuit 521 and a second excitation coil drive circuit 522.
- the first excitation coil drive circuit 521 outputs an excitation AC voltage having a constant period and amplitude from the first excitation signal output port 50pe1.
- the excitation AC voltage outputted from the first excitation signal output port 50pe1 referred to as a first excitation signal, referred to the voltage value of the first excitation signal and the first excitation voltage V 1.
- V 1 A 1 ⁇ sin ( ⁇ t)
- the second excitation coil drive circuit 522 has the same frequency as the excitation AC voltage output from the first excitation coil drive circuit 521 and has an opposite phase (the phase is shifted by ⁇ ).
- the excitation AC voltage set to is output from the second excitation signal output port 50pe2.
- the excitation AC voltage outputted from the second excitation signal output port 50pe2 called the second excitation signal, referred to the voltage value of the second excitation signal and the second excitation voltage V 2.
- Second excitation voltage V 2 when the amplitude and A 2, is expressed by the following equation.
- V 2 ⁇ A 2 ⁇ sin ( ⁇ t)
- the amplitudes A 1 and A 2 of the first excitation voltage V 1 and the second excitation voltage V 2 are set according to the characteristics of the first resolver 110 and the second resolver 120.
- the assist ECU 50 stores the sine wave signal in digital form, outputs the sine wave signal to the first excitation coil drive circuit 521, and outputs a signal obtained by inverting the sine wave signal. Output to the second excitation coil drive circuit 522.
- Each drive circuit 521, 522 includes a D / A converter (not shown) that converts an input digital signal into an analog voltage signal, and an amplifier (not shown) that amplifies the output signal of the D / A converter.
- the excitation signal expressed by the above equation is output from the amplifier.
- the excitation signal can be generated by various other methods.
- a pulse train signal is supplied to the first excitation coil drive circuit 521, and a pulse train signal obtained by inverting the pulse train signal is supplied to the second excitation coil drive circuit 522.
- each of the drive circuits 521 and 522 may perform waveform shaping processing on the pulse train signal to output two types of sine wave voltages having opposite phases.
- the first excitation coil drive circuit 521 and the second excitation coil drive circuit 522 are independently controlled by a command from the microcomputer in the assist ECU 50. Therefore, the assist ECU 50 can output the first excitation signal and the second excitation signal independently.
- the first excitation signal is supplied to the first excitation coil 111 of the first resolver 110 via the first excitation line 210.
- the second excitation signal is supplied to the second excitation coil 121 of the second resolver 120 via the second excitation line 220.
- the AC voltage signal output from the first sin phase detection coil 112 is referred to as a first sin phase detection signal, and the voltage value is referred to as a first sin phase detection voltage Es1.
- the AC voltage signal output from the first cos phase detection coil 113 is referred to as a first cos phase detection signal, and the voltage value is referred to as a first cos phase detection voltage Ec1.
- Ec1 ⁇ ⁇ A 1 ⁇ cos (k ⁇ ⁇ 1 ) ⁇ sin ( ⁇ t + ⁇ )
- the AC voltage signal output from the second sin phase detection coil 122 is referred to as a second sin phase detection signal, and the voltage value is referred to as a second sin phase detection voltage Es2.
- the AC voltage signal output from the second cos phase detection coil 123 is referred to as a second cos phase detection signal, and the voltage value thereof is referred to as a second cos phase detection voltage Ec2.
- the second sin phase detection voltage Es2 and the second cos phase detection voltage Ec2 are expressed by the following equations.
- Es2 ⁇ ⁇ A 2 ⁇ sin (k ⁇ ⁇ 2 ) ⁇ sin ( ⁇ t + ⁇ )
- Ec2 ⁇ ⁇ A 2 ⁇ cos (k ⁇ ⁇ 2 ) ⁇ sin ( ⁇ t + ⁇ )
- ⁇ 1 is the angle of the rotor of the first resolver 110 directly connected to the input shaft 12 in
- ⁇ 2 is the angle of the rotor of the second resolver 120 directly connected to the output shaft 12 out
- ⁇ is the first resolver 110 and the second resolver 120.
- K is an axial multiple of the first resolver 110 and the second resolver 120
- ⁇ is a phase delay amount
- ⁇ is an angular frequency
- t time.
- the assist ECU 50 converts the first sin phase detection signal, the first cos phase detection signal, the second sin phase detection signal, and the second cos phase detection signal into the first sin phase detection line 212, the first cos phase detection line 213, and the second sin phase detection line 222, respectively. , Input via the second cos phase detection line 223.
- the assist ECU 50 inputs the first sin phase detection signal, the first cos phase detection signal, the second sin phase detection signal, and the second cos phase detection signal to the amplifiers 51s1, 51c1, 51s2, and 51c2, and amplifies the voltage of each detection signal with respect to the ground potential. Then, the amplified voltage signal is converted into a digital value by an A / D converter (not shown), and the digital value is input to a microcomputer to perform torque calculation processing.
- the torque calculation unit 32 in the assist ECU 50 includes a circuit that amplifies the first sin phase detection signal, the first cos phase detection signal, the second sin phase detection signal, and the second cos phase detection signal, converts them into digital signals, and inputs them to the microcomputer, and coil driving
- the circuit 52 and a functional unit that performs torque calculation processing by a microcomputer are included.
- Ss1 is a value obtained by multiplying the first sin phase detection voltage Es1 by a signal sin ( ⁇ t + ⁇ ) and integrating it in one cycle, Ss1 is expressed by the following equation.
- Sc1 is expressed by the following equation.
- the rotation angle ⁇ 1 can be obtained by the following equation.
- the rotation angle ⁇ 2 (rotation angle of the output shaft 12out) can be obtained by the following equation.
- Ss2 represents a value obtained by multiplying the second sin phase detection voltage Es2 by a signal sin ( ⁇ t + ⁇ ) and integrating in one cycle
- Sc2 is a signal sin ( ⁇ t + ⁇ ) to the second cos phase detection voltage Ec2. Represents the value obtained by multiplying by and integrated in one cycle.
- Kb is a proportionality constant determined according to the torsional characteristics of the torsion bar 12a, and is stored in the microcomputer in advance.
- the detection voltages Es1, Ec1, Es2, and Ec2 are sampled at equal intervals of three or more times within one cycle of the excitation signal. Then, the sampled detection voltages Es1, Ec1, Es2, and Ec2 are multiplied by sin ( ⁇ t + ⁇ ), respectively, and the multiplied values are added for one period (for example, three times), thereby obtaining the above Ss1, Sc1, Ss2, and Sc2. May be calculated.
- Ss1, Sc1, Ss2, and Sc2 are values corresponding to the amplitudes of the detection voltages Es1, Ec1, Es2, and Ec2 (values obtained by multiplying the amplitude by a constant), Ss1, Sc1, Ss2, and Sc2 are hereinafter referred to as amplitudes. Call.
- the disconnection is caused by a disconnection of a wire harness wired between the assist ECU 50 and the resolver unit 100 or a contact failure of a connector connecting the wire harness to the assist ECU 50 and the resolver unit 100. Accordingly, here, disconnection in the resolver unit 100 does not occur.
- the operation when the first excitation line 210 is disconnected will be described.
- the second excitation signal is supplied to the resolver unit 100 using only the outside unit second excitation line 220b.
- the second excitation signal output from the assist ECU 50 flows in two routes at the connection point Xb of the electric resistance element 230 connected to the in-unit second excitation line 220a.
- One route is a route that flows from the connection point Xb to the second excitation coil 121 as it is through the second excitation line 220a in the unit.
- the other route is a route that flows from the connection point Xb to the first excitation coil 111 via the electric resistance element 230 and the first excitation line 210a in the unit.
- the current that flows through the first excitation coil 111 and the second excitation coil 121 flows through the common ground line 240 and returns to the assist ECU 50.
- the first excitation coil 111 and the second excitation coil 121 are excited.
- the excitation signal is an alternating voltage, it flows in the reverse direction in the route, but here, the flow of current in a state where a positive voltage is applied is described.
- the current flowing through the first exciting coil 111 is smaller than that in the normal state due to the influence of the electric resistance element 230. Therefore, the 1sin phase detection voltage EsI, and, although the first 1cos phase detection voltage Ec1 decreases, the ratio of the detected voltage related to the calculation of the rotation angle theta 1 is the same as normal. Therefore, the disconnection of the first excitation line 210 does not affect the calculation result of the rotation angle ⁇ 1 .
- the first excitation coil 111 and the second excitation coil 121 are supplied with the excitation AC signal having the same phase, it is necessary to add a negative sign to the calculation of the rotation angle ⁇ 1 (multiply by ⁇ 1). There is.
- the operation when the second excitation line 220 is disconnected will be described.
- the first excitation signal is supplied to the resolver unit 100 using only the outside unit first excitation line 210b.
- the second excitation signal output from the assist ECU 50 flows in two routes at the connection point Xa of the electric resistance element 230 connected to the first excitation line 210a in the unit.
- One route is a route that flows from the connection point Xa to the first excitation coil 111 as it is through the first excitation line 210a in the unit.
- the other route is a route that flows from the connection point Xa to the second excitation coil 121 via the electric resistance element 230 and the second excitation line 220a in the unit.
- the current that flows through the first excitation coil 111 and the second excitation coil 121 flows through the common ground line 240 and returns to the assist ECU 50. As a result, the first excitation coil 111 and the second excitation coil 121 are excited.
- the current flowing through the second exciting coil 121 is smaller than that in the normal state due to the influence of the electric resistance element 230. Therefore, the 2sin phase detection voltage Es2, and, although the first 2cos phase detection voltage Ec2 decreases, the ratio of the detected voltage related to the calculation of the rotation angle theta 2 is the same as normal. Therefore, disconnection of the second excitation line 220 does not affect the calculation result of the rotation angle theta 2.
- the excitation AC signal having the same phase is supplied to the first excitation coil 111 and the second excitation coil 121, the negative sign is removed from the calculation of the rotation angle ⁇ 2 (do not multiply by ⁇ 1). There is a need.
- the torque calculation unit 32 can detect the disconnection based on the decrease in the detected voltage, and can identify the disconnected excitation line.
- the torque calculator 32 calculates the square sum of the amplitudes Ss1, Sc1 (Ss1 2 + Sc1 2 ) based on the amplitudes Ss1, Sc1, Ss2, Sc2 obtained for calculating the rotation angles ⁇ 1 , ⁇ 2.
- the value is less than the reference value Se, it is determined that the first excitation line 210 is disconnected.
- the value of the sum of squares of the amplitudes Ss2 and Sc2 (Ss2 2 + Sc2 2 ) is less than the reference value Se, it is determined that the second excitation line 220 is disconnected.
- the reference value Se is a set value that is set in advance in order to determine whether or not there is a disconnection.
- the torque calculation unit 32 can calculate an appropriate steering torque Tr by correcting the sign (positive / negative) of the rotation angle ⁇ 1 or the rotation angle ⁇ 2 based on this disconnection detection.
- the potential of the in-unit ground line 240a which is the ground line 240 in the resolver unit 100, can be maintained at zero volts even if the out-unit ground line 240b is disconnected. Therefore, the first sin phase detection coil 112, the first cos phase detection coil 113, the second sin phase detection coil 122, and the second cos phase detection coil 123 can operate normally. Thereby, the torque calculation unit 32 outputs the output voltages (detection voltages) of the first sin phase detection coil 112, the first cos phase detection coil 113, the second sin phase detection coil 122, and the second cos phase detection coil 123 at the normal time (not disconnected). It is possible to detect in the same manner as in (1).
- the steering torque Tr can be obtained from the rotation angles ⁇ 1 and ⁇ 2 by calculation.
- the torque calculator 32 Disconnection cannot be detected. Even if the ground line 240 is disconnected, the steering torque Tr can be normally detected. However, if a double failure occurs in which the first excitation line 210 or the second excitation line 220 is disconnected, the steering torque Tr cannot be detected. Therefore, the torque calculator 32 detects the disconnection of the ground line 240 at an early stage by performing a ground disconnection detection process, and notifies the driver of the necessity for repair. The ground disconnection detection process will be described later.
- FIG. 7 is a flowchart showing a steering torque detection routine.
- the steering torque detection routine is stored as a control program in the ROM of the microcomputer.
- the steering torque detection routine is repeatedly executed at a predetermined short period during a period in which the ignition key is in the on state.
- the torque calculation unit 32 operates the coil drive circuit 52 together with the start of the steering torque detection routine to start outputting the first excitation signal from the first excitation signal output port 50pe1, and the second excitation signal output port 50pe2. To start the output of the second excitation signal.
- the torque calculation unit 32 determines whether or not it is time to perform ground disconnection detection processing in step S11.
- the ground disconnection detection process is a process for diagnosing whether or not the unit ground line 240b is disconnected, and is performed at a predetermined cycle. Here, the case where it is not the timing will be described.
- the torque calculator 32 determines whether or not it is the timing for performing the resistance disconnection detection process in the subsequent step S12.
- This resistance disconnection detection process is a process for diagnosing disconnection of the electrical resistance element 230, that is, whether or not the in-unit first excitation line 210a and the in-unit second excitation line 220a are connected by the electrical resistance element 230. And is performed at a predetermined cycle set in advance. Here, the case where it is not the timing will be described.
- the torque calculation unit 32 reads the sampled detection voltages Es1, Es1, Es2, and Ec2 in the subsequent step S13, and detects the detection voltages Es1, Ec1, Based on Es2 and Ec2, amplitudes Ss1, Sc1, Ss2, and Sc2 are calculated.
- the torque calculation unit 32 is a sampling routine different from the steering torque detection routine, and samples the instantaneous values of the detection voltages Es1, Ec1, Es2, and Ec2 at a sampling period of 3 or more per excitation signal period. .
- the values obtained by multiplying the detected voltages Es1, Ec1, Es2, and Ec2 sampled by the sampling routine by sin ( ⁇ t + ⁇ ) are added for one period of the excitation signal, and the amplitudes Ss1, Sc1, Ss2, and Sc2 are added.
- Step S14 the torque calculation unit 32 determines whether the first excitation line 210 (outside the unit first excitation line 210b) or the second excitation line 220 (outside the unit second) based on the amplitudes Ss1, Sc1, Ss2, Sc2. It is determined whether the excitation line 220b) is broken. In the present embodiment, the torque calculator 32 determines that the first excitation line 210 is disconnected when the value of the sum of squares of the amplitudes Ss1 and Sc1 (Ss1 2 + Sc1 2 ) is less than the reference value Se.
- the torque calculator 32 determines that the second excitation line 220 is disconnected when the value of the sum of squares of the amplitudes Ss2 and Sc2 (Ss2 2 + Sc2 2 ) is less than the reference value Se.
- the reference value Se is such that (Ss1 2 + Sc1 2 ) or (Ss2 2 + Sc2 2 ) is larger than the reference value Se and the first value Se.
- the presence or absence of a preset disconnection can be determined so that (Ss1 2 + Sc1 2 ) or (Ss2 2 + Sc2 2 ) is smaller than the reference value Se. It is a set value.
- the torque calculation unit 32 determines whether or not it is determined in step S15 that both the first excitation line 210 and the second excitation line 220 are not disconnected. When it is determined that both the first excitation line 210 and the second excitation line 220 are not disconnected (Ss15: Yes), in step S16, the first excitation line disconnection determination flag Fe1 and the second excitation line disconnection determination flag. Both Fe2 are set to "0". The first excitation line disconnection determination flag Fe1 and the second excitation line disconnection determination flag Fe2 indicate that a disconnection is detected by “1” and that a disconnection is not detected by “0”.
- the torque calculating section 32 sets a code K 1 used in the formula of the rotation angle theta 1 to "1" (positive), the reference numeral K 2 used in the formula of the rotation angle theta 2 " Set to “1” (negative).
- step S15 If it is determined in step S15 that the first excitation line 210 or the second excitation line 220 is disconnected, the torque calculator 32 determines in step S18 whether only one excitation line is disconnected. to decide. When it is determined that both the first excitation line 210 and the second excitation line 220 are disconnected (S18: No), in step S19, the first excitation line disconnection determination flag Fe1 and the second excitation line disconnection determination flag are determined. Both Fe2 are set to "1" and the steering torque detection routine is temporarily ended. In this case, since the steering torque cannot be detected, the steering torque Tr is not calculated.
- step S18 If the torque calculation unit 32 determines in step S18 that either the first excitation line 210 or the second excitation line 220 is disconnected, only the first excitation line 210 is disconnected in step S20. It is determined whether or not. If it is determined that only the first excitation line 210 is disconnected, in step S21, the first excitation line disconnection determination flag Fe1 is set to “1”, and the second excitation line disconnection determination flag Fe2 is set to “0”. Set to. Subsequently, in step S22, the code K 1 used for calculating the rotation angle ⁇ 1 is set to “ ⁇ 1”, and the code K 2 used for calculating the rotation angle ⁇ 2 is set to “ ⁇ 1”.
- step S20 determines whether only the second excitation line 220 is disconnected (S20: No)
- the first excitation line disconnection determination flag Fe1 is set to “0” in step S23, and the first 2.
- step S24 the code K 1 used to calculate the rotation angle theta 1 is set to "1”
- Torque calculating unit 32 at step S25, to calculate the rotation angle theta 1 and the rotation angle theta 2 by the following equation.
- ⁇ 1 K 1 ⁇ (1 / k) ⁇ tan ⁇ 1 (Ss1 / Sc1)
- ⁇ 2 K 2 ⁇ (1 / k) ⁇ tan ⁇ 1 (Ss2 / Sc2)
- the torque calculation unit 32 outputs the calculated steering torque Tr to the assist calculation unit 31 in step S27.
- the assist calculation unit 31 calculates a target assist torque using the steering torque Tr, and outputs a PWM control signal to the motor drive circuit 40 so that a target current corresponding to the target assist torque flows to the electric motor 21. Thereby, an appropriate steering assist torque is generated from the electric motor 21.
- the torque calculation unit 32 ends the steering torque detection routine when the process of step S27 or step S19 is performed. Then, the steering torque detection routine is repeated at a predetermined short cycle.
- the torque calculation unit 32 determines that it is the ground disconnection detection timing in step S11, the process proceeds to step S30.
- the torque detection device can detect the steering torque Tr as it is even when the ground line 240 (outside unit ground line 240b) is disconnected.
- the torque calculation unit 32 periodically executes the ground disconnection detection process to detect the disconnection of the ground line 240 at an early stage and prompt the driver to repair.
- the ground disconnection detection process may be performed periodically immediately after starting the steering torque detection routine and periodically at a preset cycle after the start.
- FIG. 8 shows a ground disconnection detection subroutine of step S30 in the steering torque detection routine.
- the torque calculation unit 32 uses the steering torque Tr (n ⁇ 1) calculated in the steering torque detection routine of the immediately previous time (one control cycle) at step S31 as the current steering torque. Set to Tr. This is because the steering torque cannot be detected when the ground disconnection detection process is performed as described later.
- the steering torque Tr may be set to zero.
- the torque calculator 32 stops the first excitation signal output from the first excitation signal output port 50pe1, and fixes the potential of the first excitation signal output port 50pe1 to zero volts.
- the unit-external ground line 240b is disconnected, no exciting current flows through the first exciting coil 111. Therefore, the detection voltage Es1 of the first sin phase detection coil 112 and the detection voltage Ec1 of the first cos phase detection coil 113 are basically zero volts.
- the second excitation signal output from the second excitation signal output port 50pe2 flows to the second excitation coil 121 through the second excitation line 220, and the unit ground.
- the electric potential of the in-unit ground line 240a is 1 ⁇ 2 of the excitation voltage. Accordingly, a voltage is generated at the first sin phase signal input port 50ps1 and the first cos phase signal input port 50pc1 of the assist ECU 50.
- the torque calculator 32 diagnoses the disconnection of the external ground line 240b using such characteristics.
- the torque calculation unit 32 calculates the amplitudes Ss1 and Sc1 by the method described above.
- step S34 it is determined whether or not the value of the sum of squares of the amplitudes Ss1 and Sc1 (Ss1 2 + Sc1 2 ) is equal to or less than the reference value Sg.
- the reference value Sg when the unit outside the ground line 240b is not broken, (Ss1 2 + Sc1 2) is smaller than the reference value Sg, and, when the unit outside the ground line 240b is broken, (Ss1 2 + Sc1 2 ) is a set value that can determine the presence or absence of a preset disconnection so that + Sc1 2 ) is larger than the reference value. If the ground line 240b outside the unit is not broken, the amplitudes Ss1 and Sc1 are basically zero, but a voltage due to noise may be detected. Therefore, the reference value Sg is set in consideration of noise and the like. Is done.
- step S35 the ground line disconnection determination flag Fg. Is set to “0”, and it is determined that the value of the sum of squares of the amplitudes Ss1 and Sc1 (Ss1 2 + Sc1 2 ) exceeds the reference value Sg (S34: No), a ground line disconnection determination flag in step S36 Fg is set to “1”.
- the ground line disconnection determination flag Fg indicates that a disconnection is detected by “1”, and indicates that a disconnection is not detected by “0”.
- step S37 When the torque calculation unit 32 sets the ground line disconnection determination flag Fg, subsequently, in step S37, the output of the first excitation signal from the first excitation signal output port 50pe1 is resumed. Therefore, it returns to the state where the steering torque Tr can be detected.
- the torque calculator 32 ends the present subroutine and advances the process to step S27 of the main routine. In this case, in step S27, the steering torque Tr set in step S31 is output to the assist calculation unit 31.
- the output of the first excitation signal is stopped in step S32. Instead, the output of the second excitation signal is stopped.
- the output voltage may be fixed at zero volts.
- steps S33 and S34 the value of the sum of squares of the amplitudes Ss2 and Sc2 (Ss2 2 + Sc2 2 ) may be compared with the reference value Sg.
- the torque calculation unit 32 determines that it is the resistance disconnection detection timing in step S12 of the steering torque detection routine (FIG. 7), the process proceeds to step S40.
- the torque detection device can detect the steering torque Tr even if one of the unit outside excitation lines 210b (220b) is disconnected.
- the torque calculation unit 32 periodically detects the resistance disconnection detection process, thereby detecting the disconnection of the electric resistance element 230 at an early stage and prompting the driver to repair it.
- the resistance disconnection detection process may be performed periodically immediately after starting the steering torque detection routine and periodically at a preset period after the start.
- FIG. 9 shows a ground disconnection detection subroutine of step S40 in the steering torque detection routine.
- the torque calculation unit 32 calculates the steering torque Tr (n ⁇ 1) calculated in the steering torque detection routine of the immediately previous time (one control cycle) at step S41 as the current steering torque. Set to Tr. This is because the steering torque cannot be detected when the resistance disconnection detection process is performed as described later. In addition, what is necessary is just to set the steering torque Tr to zero, when the timing which performs a resistance disconnection detection process is immediately after starting of a steering torque detection routine.
- the torque calculator 32 stops the first excitation signal output from the first excitation signal output port 50pe1, and puts the first excitation signal output port 50pe1 into an open state (high impedance). In this case, it is set to the same state as the state where the first outside unit excitation line 210b is disconnected. Therefore, if the rotation angle ⁇ 1 is calculated by setting the control logic when the outside first unit excitation line 210b is disconnected, that is, the sign K 1 is set to “ ⁇ 1”, the proper rotation angle ⁇ 1 can be detected. Should be able to. The torque calculator 32 diagnoses the disconnection of the electric resistance element 230 using such characteristics.
- step S45 the torque calculator 32 calculates the rotation angle ⁇ 1 (n ⁇ 1) calculated in step S25 of the immediately previous steering torque detection routine (step S25) and the current step S44.
- a deviation ⁇ 1 (
- ) from the rotation angle ⁇ 1 is calculated, and it is determined whether or not the deviation ⁇ 1 is equal to or smaller than a reference value ⁇ r.
- the reference value [theta] r when the electrical resistance element 230 is not broken, becomes smaller than the difference [Delta] [theta] 1 is the reference value [theta] r, when the electric resistance element 230 is broken, larger than deviation [Delta] [theta] 1 is the reference value [theta] r It is a set value that can determine the presence or absence of a preset disconnection.
- step S46 the resistance disconnection determination flag Fr is set to “0”, and the deviation ⁇ 1 is the reference. If it is determined that the value ⁇ r is exceeded (S45: Yes), the resistance disconnection determination flag Fr is set to “0” in step S47.
- the resistance disconnection determination flag Fr indicates that a disconnection is detected by “1”, and indicates that a disconnection is not detected by “0”.
- step S48 the torque calculation unit 32 resumes the output of the first excitation signal from the first excitation signal output port 50pe1. Therefore, it returns to the state where the steering torque Tr can be detected.
- step S48 the torque calculator 32 ends the present subroutine and advances the process to step S27 of the main routine. In this case, in step S27, the steering torque Tr set in step S41 is output to the assist calculation unit 31.
- the first excitation signal output port 50pe1 is opened in step S42.
- the second excitation signal output port 50pe2 is opened. You may make it.
- the amplitude Ss2, the rotation angle theta 2, calculated on the Sc2, based on a deviation between the rotation angle theta 2 between the immediately preceding rotational angle ⁇ 2 (n-1) The disconnection may be determined.
- the disconnection abnormality process executed by the torque calculator 32 will be described.
- the presence / absence of disconnection of the first outside-unit excitation line 210b, the second outside-unit excitation line 220b, the outside-unit ground line 240b, and the electric resistance element 230 was determined.
- an abnormality notification to the driver and a steering assist stop command to the assist calculation unit 31 are performed based on the disconnection determination result.
- FIG. 10 is a flowchart showing a disconnection abnormality processing routine.
- the disconnection abnormality processing routine is stored as a control program in the ROM of the microcomputer.
- the disconnection abnormality processing routine is repeatedly executed at a predetermined short period in parallel with the above-described steering torque detection routine.
- step S51 the torque calculation unit 32 has all of the first excitation line disconnection determination flag Fe1, the second excitation line disconnection determination flag Fe2, the ground line disconnection determination flag Fg, and the resistance disconnection determination flag Fr. It is determined whether or not “0” is set, and when all the flags are set to “0”, that is, when no disconnection is detected anywhere, this routine is temporarily ended.
- step S53 the torque calculator 32 determines whether both the first excitation line disconnection determination flag Fe1 and the second excitation line disconnection determination flag Fe2 are set to “1”.
- the torque calculation unit 32 performs assist calculation in step S54.
- a torque detection impossible signal is output to the unit 31.
- the assist calculation unit 31 stops the steering assist control.
- step S53 If the determination in step S53 is “No”, it is determined in step S55 whether or not both of the first excitation line disconnection determination flag Fe1 and the ground line disconnection determination flag Fg are set to “1”. to decide. Even when the two disconnection determination flags Fe1 and Fg are both set to “1” (S55: Yes), the process of step S54 is performed because the steering torque Tr cannot be detected.
- step S55 If the determination in step S55 is “No”, it is determined in step S56 whether both the second excitation line disconnection determination flag Fe2 and the ground line disconnection determination flag Fg are set to “1”. to decide. Even when the two disconnection determination flags Fe2 and Fg are both set to “1” (S56: Yes), the steering torque Tr cannot be detected, so the process of step S54 is performed.
- step S56 If the determination in step S56 is “No”, it is determined in step S57 whether both the first excitation line disconnection determination flag Fe1 and the resistance disconnection determination flag Fr are set to “1”. To do. Even when the two disconnection determination flags Fe1 and Fr are both set to “1” (S57: Yes), the process of step S54 is performed because the steering torque Tr cannot be detected.
- step S57 If the determination in step S57 is “No”, it is determined in step S58 whether both the second excitation line disconnection determination flag Fe2 and the resistance disconnection determination flag Fr are set to “1”. To do. Even when the two disconnection determination flags Fe2 and Fr are both set to "1" (S58: Yes), the process of step S54 is performed because the steering torque Tr cannot be detected.
- step S58 the torque calculation unit 32 can detect the steering torque Tr, and thus the process of step S54 is skipped and the present routine is temporarily ended.
- the torque detection impossible signal Is output. Further, when the disconnection of the electrical resistance element 230 and the disconnection of the first outside excitation line 210b or the second excitation line outside the unit 220b are detected at the same time, a torque detection impossible signal is output.
- a line for supplying excitation signals to the first excitation coil 111 and the second excitation coil 121 is provided independently, and the first excitation line 210 that is the supply line is provided. Since the configuration in which the second excitation line 220 is connected by the electric resistance element 230 in the resolver unit is adopted, the steering torque can be detected even if one of the excitation lines is disconnected.
- the excitation signal is generated so that the first excitation signal supplied to the first excitation line 210 and the second excitation signal supplied to the second excitation line 220 are in opposite phases (signals with inverted voltage waveforms). Therefore, the steering torque can be detected even when the ground line 240 is disconnected. For this reason, steering assist can be continued in the electric power steering apparatus. Therefore, the reliability of the electric power steering device is improved.
- FIG. 14 shows a schematic configuration of a conventional torque detection device expressed in comparison with the torque detection device of the present embodiment.
- the number of wires connecting the resolver unit 100 and the assist ECU 50 is increased by one compared to that of the conventional torque detection device.
- the reliability against disconnection can be improved. For example, when it is attempted to improve the reliability with respect to the disconnection of the excitation line and the ground line with the conventional torque detection device, one excitation line EL and one ground line GL are added as shown by a broken line in FIG.
- the number of wires in the wire harness is increased by one, so that the configuration is not complicated. Further, since the first excitation coil 111 and the second excitation coil 121 are driven using the first excitation signal and the second excitation signal that are in opposite phases, the steering torque is detected even when the ground line 240 is disconnected. be able to.
- the torque detection device of the present embodiment can ensure high reliability against disconnection even if the increase in the number of wires in the wire harness is limited to one. Moreover, since the structure of each resolver 110,120 is hardly different from the conventional one, it can be easily implemented.
- first excitation line 210, the second excitation line 220, the electric resistance element 230, and the ground line 240 are diagnosed for disconnection, and when these disconnections are detected, the warning lamp 65 is turned on to repair the driver. Prompt. Therefore, it is possible to suppress a problem that the steering torque cannot be detected due to a double failure in which there are two disconnections.
- the assist ECU 50 outputs a first excitation signal and a second excitation signal having opposite phases to the resolver unit 100 to drive the first excitation coil 111 and the second excitation coil 121.
- the first excitation signal and the second excitation signal may be in the same phase during normal operation (when no disconnection occurs). In that case, since no current flows through the electric resistance element 230 connecting the first excitation line 210 and the second excitation line 220, the electric resistance element 230 does not generate heat and energy is saved.
- FIG. 11 is a flowchart showing an excitation signal control routine executed by the torque calculator 32 as a first modification.
- the excitation signal control routine is stored as a control program in the ROM of the microcomputer, and is repeatedly executed at a predetermined short period in parallel with the above-described steering torque detection routine.
- the torque calculator 32 determines whether or not the ground line disconnection determination flag Fg is set to “0” in step S61, and the ground line disconnection determination flag Fg is set to “0”. If set, in step S62, the first excitation signal and the second excitation signal are outputted in the same phase. On the other hand, when the ground line disconnection determination flag Fg is set to “1”, in step S63, the first excitation signal and the second excitation signal are output in opposite phases. Thus, when the phase of the excitation signal is determined, the excitation signal control routine is once ended. In the case of the first excitation signal and the second excitation signal in phase, the rotation angle theta 1, the reference numeral K 1, K 2 used in the theta 2 of the formula in the same.
- the first excitation signal and the second excitation signal when the disconnection of the ground line 240 is not detected, the first excitation signal and the second excitation signal have the same phase, so that no current flows through the electric resistance element 230. As a result, the electric resistance element 230 does not generate heat. It also saves energy.
- the first excitation signal and the second excitation signal are in opposite phases, so that the potential of the in-unit ground line 240a in the resolver unit 100 can be maintained at zero volts. For this reason, the 1st sin phase detection coil 112, the 1st cos phase detection coil 113, the 2nd sin phase detection coil 122, and the 2nd cos phase detection coil 123 operate
- the first excitation coil 111 or the second excitation coil 121 is driven via the electric resistance element 230 when the first excitation line 210 or the second excitation line 220 is disconnected. Therefore, the phase delay amount ⁇ of the detection signal with respect to the excitation signal changes between the normal time (at the time of non-disconnection) and the disconnection time, and the calculation accuracy of the amplitude is lowered. Therefore, in the second modification, when the disconnection of the first excitation line 210 or the second excitation line 220 is detected, the value of the phase delay amount ⁇ in the calculation formula is taken into consideration of the resistance value of the electric resistance element 230. Change to a value.
- FIG. 12 is a flowchart showing a phase delay amount switching routine executed by the torque calculation unit 32 as a second modification.
- the phase delay amount switching routine is stored as a control program in the ROM of the microcomputer, and is repeatedly executed at a predetermined short period in parallel with the above-described steering torque detection routine.
- the torque calculation unit 32 determines whether or not the first excitation line disconnection determination flag Fe1 is set to “0” in step S71, and the first excitation line disconnection determination flag Fe1. Is set to “0” (S71: Yes), in step S72, it is determined whether or not the second excitation line disconnection determination flag Fe2 is set to “0”. If “Yes” is determined in step S72, that is, if disconnection of the first excitation line 210 and the second excitation line 220 is not detected, the phase delay amount ⁇ 1 in the first resolver 110 is set to ⁇ 0 in step S73. And the phase delay amount ⁇ 2 in the second resolver 120 is set to ⁇ 0.
- This phase delay amount ⁇ 0 is a set value in which the phase delay amount when an excitation signal is supplied to the excitation coils 111 and 121 without passing through the electric resistance element 230 is set in advance.
- the phase delay amount ⁇ 1 is the phase delay amount ⁇ used for calculating the amplitudes Ss1 and Sc1 in the first resolver 110
- the phase delay amount ⁇ 2 is the phase used for calculating the amplitudes Ss2 and Sc2 in the second resolver 120.
- the delay amount ⁇ is the phase delay amount when an excitation signal is supplied to the excitation coils 111 and 121 without passing through the electric resistance element 230 is set in advance.
- the phase delay amount ⁇ 1 is the phase delay amount ⁇ used for calculating the amplitudes Ss1 and Sc1 in the first resolver 110
- the phase delay amount ⁇ 2 is the phase used for calculating the amplitudes Ss2 and Sc2 in the second resolver 120.
- the delay amount ⁇ is the phase delay amount ⁇ used for calculating
- step S72 if it is determined as “No” in step S72, that is, if the disconnection of only the second excitation line 220 is detected, the phase delay amount ⁇ 1 in the first resolver 110 is set to ⁇ 0 in step S74.
- the phase delay amount ⁇ 2 in the second resolver 120 is set to ⁇ r.
- This phase delay amount ⁇ r is a preset value for setting the phase delay amount when an excitation signal is supplied to the excitation coil 111 or the excitation coil 121 via the electrical resistance element 230, and the resistance value R of the electrical resistance element 230 is set to Set to a value that takes into account.
- step S75 it is determined in step S75 whether or not the second excitation line disconnection determination flag Fe2 is set to “0”. If it is determined as “Yes” in step S75, that is, if disconnection of only the first excitation line 210 is detected, the phase delay amount ⁇ 1 in the first resolver 110 is set to ⁇ r in step S76, and the second The phase delay amount ⁇ 2 in the resolver 120 is set to ⁇ 0. If “No” is determined in step S75, the disconnection of both the first excitation line 210 and the second excitation line 220 has been detected, so that the detection of the steering torque Tr is impossible, and the phase delay amount Do not set ⁇ 1 and ⁇ 2.
- the torque calculation unit 32 once ends the phase delay amount switching routine when the phase delay amounts ⁇ 1 and ⁇ 2 are set in steps S73, S74, and S76.
- the torque calculator 32 repeatedly executes the phase delay amount switching routine at a predetermined short cycle.
- the phase delay amount ⁇ is switched between the normal time (non-disconnection) and the disconnection time, so that appropriate amplitudes Ss1, Sc1, Ss2, and Sc2 can be calculated.
- the calculation accuracy of the rotation angles ⁇ 1 and ⁇ 2 is improved, and a more accurate steering torque Tr can be detected.
- the phase delay amount ⁇ in the calculation formula is switched.
- an inductor 231 is connected in series to the electric resistance element 230.
- a series circuit of the electric resistance element 230 and the inductor 231 is connected between the first in-unit excitation line 210a and the second in-unit excitation line 220a.
- the inductance value of the inductor 231 may be set in advance so that the phase delay amount ⁇ is equal between the normal time and the disconnection time.
- the potential of the ground line 240 is set to zero volts. For this reason, the coil drive circuit 52 that generates the first excitation signal and the second excitation signal requires positive and negative power supplies. Therefore, in the fourth modification, the potential of the ground line 240, that is, the potential of the ground port 100pg is fixed to about half of the power supply voltage so that the excitation signal can be generated only by the positive power supply.
- ground line 240 is set to 2.5V.
- the ground line 240 is called the common line 240
- the ground port 100pg and the ground port 50pg are called the common port 100pg and the common port 50pg.
- ground is read as “common”.
- V 1 A 1 ⁇ sin ( ⁇ t) + V DD / 2
- V 2 ⁇ A 2 ⁇ sin ( ⁇ t) + V DD / 2
- the coil drive circuit 52 of the assist ECU 50 may output the first excitation signal and the second excitation signal represented by the above formula from the first excitation signal output port 50pe1 and the second excitation signal output port 50pe2.
- the potential of the internal common line 240a can be maintained at V DD / 2 even when the external common line 240b is disconnected. Therefore, since the first sin phase detection coil 112, the first cos phase detection coil 113, the second sin phase detection coil 122, and the second cos phase detection coil 123 operate normally, the rotation angle ⁇ is the same as in the normal state (when no disconnection occurs). 1, can be obtained by calculating the steering torque Tr from the theta 2.
- the first excitation signal and the second excitation signal are generated so that their phases are opposite to each other, but it is not always necessary to have the opposite phases.
- the disconnection of the ground line 240, the disconnection of the excitation lines 210 and 220, and the disconnection of the electric resistance element 230 are detected, but it is not always necessary to have such a disconnection detection function. .
- the microcomputers provided in the assist ECU 50 are configured to calculate the rotation angles ⁇ 1 and ⁇ 2 and the steering torque Tr, but the rotation angles ⁇ 1 and ⁇ 2 are calculated.
- the RD converter (Resolver-Digital-Converter) can output the digital angle data calculated by the RD converter to the assist ECU 50 and calculate the steering torque Tr by the microcomputer of the assist ECU 50.
- the RD converter and the resolver unit 100 are connected by a wire harness. Further, the RD converter and the assist ECU constitute the torque calculation unit of the present invention.
- the disconnection detection of the excitation lines 210 and 220 or the disconnection detection of the ground line 240 is performed based on the sum of squares of amplitude ((Ss1 2 + Sc1 2 ) or (Ss2 2 + Sc2 2 )).
- the ground line 240 For detecting disconnection of the ground line 240, for example, when at least one of the absolute value (
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Abstract
Description
V1=A1・sin(ωt)
V2=-A2・sin(ωt)
Es1=α・A1・sin(k・θ1)・sin(ωt+φ)
Ec1=α・A1・cos(k・θ1)・sin(ωt+φ)
Es2=-α・A2・sin(k・θ2)・sin(ωt+φ)
Ec2=-α・A2・cos(k・θ2)・sin(ωt+φ)
ここで、θ1は入力シャフト12inに直結した第1レゾルバ110のロータの角度、θ2は出力シャフト12outに直結した第2レゾルバ120のロータの角度、αは第1レゾルバ110および第2レゾルバ120の変圧比、kは第1レゾルバ110および第2レゾルバ120の軸倍角、φは位相遅れ量、ωは角周波数、tは時間を表す。
Tr=Kb・(θ1-θ2)
ここでKbは、トーションバー12aの捩り特性に応じて決まる比例定数であり、予めマイコン内に記憶されている。
Vg=(V1+V2)/2=0
この場合、第1sin相検出コイル112、第1cos相検出コイル113、第2sin相検出コイル122、第2cos相検出コイル123の検出電圧が通常時と変わらないため、トルク演算部32ではグランドライン240の断線を検出することができない。グランドライン240が断線した場合でも、操舵トルクTrを正常に検出することができるものの、さらに、第1励磁ライン210あるいは第2励磁ライン220が断線する2重故障が発生した場合には、操舵トルクTrを検出することができなくなる。そこで、トルク演算部32では、グランド断線検出処理を実行することにより、グランドライン240の断線を早期に検出してドライバーに修理の必要性を報知する。このグランド断線検出処理については、後述する。
θ1=K1・(1/k)・tan-1(Ss1/Sc1)
θ2=K2・(1/k)・tan-1(Ss2/Sc2)
Tr=Kb・(θ1-θ2)
θ1=-(1/k)・tan-1(Ss1/Sc1)
V1=A1・sin(ωt)+VDD/2
V2=-A2・sin(ωt)+VDD/2
Claims (8)
- 第1励磁コイルに励磁用交流信号が供給されてシャフトの第1軸方向位置における回転角に応じた検出信号を出力する第1レゾルバと、第2励磁コイルに励磁用交流信号が供給されて前記シャフトの第2軸方向位置における回転角に応じた検出信号を出力する第2レゾルバとを有するレゾルバユニットと、
前記レゾルバユニットとワイヤハーネスを介して接続され、前記第1励磁コイルおよび前記第2励磁コイルに励磁用交流信号を供給するとともに、前記第1レゾルバおよび前記第2レゾルバから出力される検出信号をそれぞれ入力して前記シャフトの第1軸方向位置における第1回転角および第2軸方向位置における第2回転角を計算し、前記計算した第1回転角と第2回転角とに基づいて前記シャフトの軸回り方向に働くトルクを計算により求めるトルク演算部と
を備えたトルク検出装置において、
前記トルク演算部は、前記第1励磁コイルに対しては第1励磁ラインを介して前記励磁用交流信号を供給し、前記第2励磁コイルに対しては前記第1励磁ラインとは異なる第2励磁ラインを介して前記励磁用交流信号を供給し、
前記レゾルバユニットは、前記第1励磁ラインと前記第2励磁ラインとを電気的に接続する電気抵抗素子を備えたことを特徴とするトルク検出装置。 - 前記第1励磁コイルは、前記第1励磁コイルの一端に接続される第1励磁ラインと、前記第1励磁コイルの他端に接続される共通グランドラインにより前記トルク演算部と接続され、
前記第2励磁コイルは、前記第2励磁コイルの一端に接続される第2励磁ラインと、前記第2励磁コイルの他端に接続される前記共通グランドラインにより前記トルク演算部と接続され、
前記トルク演算部は、前記第1励磁ラインおよび前記第2励磁ラインに、互いに同じ周波数であって位相が逆になる励磁用交流信号を別々に出力する逆位相コイル駆動回路を備えたことを特徴とする請求項1記載のトルク検出装置。 - 前記第1レゾルバの出力する検出信号に基づいて前記第1励磁ラインの断線を検出する第1励磁ライン断線検出手段と、
前記第2レゾルバの出力する検出信号に基づいて前記第2励磁ラインの断線を検出する第2励磁ライン断線検出手段と、
前記第1励磁ラインの断線が検出された場合に、前記計算される第1回転角の符号を反転し、前記第2励磁ラインの断線が検出された場合に、前記計算される第2回転角の符号を反転する回転角補正手段と
を備えたことを特徴とする請求項2記載のトルク検出装置。 - 前記第1励磁ラインの断線が検出された場合に、前記第1レゾルバの出力する検出信号の位相遅れ量を補正し、前記第2励磁ラインの断線が検出された場合に、前記第2レゾルバの出力する検出信号の位相遅れ量を補正する位相遅れ量補正手段を備えたことを特徴とする請求項3記載のトルク検出装置。
- 前記電気抵抗素子にインダクタを直列に接続して、前記第1励磁ラインあるいは前記第2励磁ラインの断線時に前記第1レゾルバの出力する検出信号の位相遅れ量あるいは前記第2レゾルバの出力する検出信号の位相遅れ量が変化しないようにしたことを特徴とする請求項3記載のトルク検出装置。
- 前記第1励磁ラインの断線、あるいは、前記第2励磁ラインの断線が検出されているときに異常報知を行う励磁ライン断線報知手段を備えたことを特徴とする請求項3ないし請求項5の何れか一項記載のトルク検出装置。
- 前記第1励磁ラインあるいは前記第2励磁ラインの一方を、前記共通グランドラインの設定電位と同電位に設定し、その状態における前記第1レゾルバあるいは前記第2レゾルバの検出信号に基づいて、前記共通グランドラインの断線を検出するグランドライン断線検出手段と、
前記共通グランドラインの断線が検出されているときに異常報知を行うグランドライン断線報知手段と
を備えたことを特徴とする請求項2ないし請求項6の何れか一項記載のトルク検出装置。 - 前記第1励磁ラインあるいは前記第2励磁ラインの一方を前記トルク演算部で開放し、その状態において計算した第1回転角あるいは第2回転角に基づいて、前記電気抵抗素子の断線を検出する抵抗断線検出手段と、
前記電気抵抗素子の断線が検出されているときに異常報知を行う抵抗断線報知手段と
を備えたことを特徴とする請求項1ないし請求項7の何れか一項記載のトルク検出装置。
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US13/259,970 US8656791B2 (en) | 2010-08-25 | 2010-08-25 | Torque detection apparatus |
PCT/JP2010/064333 WO2012025999A1 (ja) | 2010-08-25 | 2010-08-25 | トルク検出装置 |
CN201080068766.3A CN103080715B (zh) | 2010-08-25 | 2010-08-25 | 扭矩检测装置 |
JP2011502965A JP5051404B2 (ja) | 2010-08-25 | 2010-08-25 | トルク検出装置 |
EP10849618.3A EP2610601A4 (en) | 2010-08-25 | 2010-08-25 | TORQUE DETECTION DEVICE |
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JP7306648B2 (ja) * | 2019-03-28 | 2023-07-11 | 日立Astemo株式会社 | トルク検出装置及びパワーステアリング装置 |
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JP2013257230A (ja) * | 2012-06-13 | 2013-12-26 | Jtekt Corp | 回転角センサ及び回転角センサの異常検出装置 |
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JP2017134029A (ja) * | 2016-01-29 | 2017-08-03 | オムロン株式会社 | ロードセル入力ユニット |
US10605688B2 (en) | 2016-01-29 | 2020-03-31 | Omron Corporation | Load cell input unit |
JP2018080937A (ja) * | 2016-11-14 | 2018-05-24 | 多摩川精機株式会社 | 検出器 |
Also Published As
Publication number | Publication date |
---|---|
CN103080715B (zh) | 2014-08-20 |
JP5051404B2 (ja) | 2012-10-17 |
JPWO2012025999A1 (ja) | 2013-10-28 |
EP2610601A4 (en) | 2014-12-10 |
US8656791B2 (en) | 2014-02-25 |
US20130145865A1 (en) | 2013-06-13 |
CN103080715A (zh) | 2013-05-01 |
EP2610601A1 (en) | 2013-07-03 |
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