Disclosure of Invention
In view of the foregoing problems in the prior art, it is an object of the present invention to provide a control system for a six-degree-of-freedom swing table, which improves the foregoing problems.
A control system for a six degree of freedom swing table, comprising: the hydraulic source control unit is used for controlling the starting/stopping, pressurizing/unloading of the hydraulic source, so that the hydraulic source can provide hydraulic pressure with corresponding flow and pressure for the swing platform in time and drive the actuator to act; the servo control unit is used for acquiring displacement signals and pressure signals of the actuator in real time and controlling the servo valve so as to control the actuator to move and control the swing table in real time in a closed loop manner; the monitoring unit is used for receiving control instructions of operators, controlling the hydraulic source control unit to control the oil pressure of the actuator of the swinging platform, enabling the swinging platform to be driven by the actuator to complete various movements, monitoring the working state of the swinging platform through the servo control unit and realizing closed-loop feedback control; the monitoring unit is respectively in communication connection with the hydraulic source control unit and the servo control unit, the swinging platform comprises an actuator, a servo valve is arranged on the actuator, a load is installed on the swinging platform, and the driving capacity curve of the actuator envelopes the load motion track curve and the curve is tangent.
Preferably, the servo control unit is integrated in a servo control cabinet and comprises a servo controller, a signal conditioning unit and a UPS power supply, wherein the servo controller controls the servo valve through the signal conditioning unit; and the servo controller is provided with an optical fiber reflection memory card which is used for receiving data information transmitted by a user in real time and realizing function expansion.
Preferably, the hydraulic source control unit is integrated in the PLC control cabinet and comprises a hydraulic control cabinet, an oil source starting cabinet and a direct-current stabilized voltage supply, wherein the hydraulic control cabinet receives a control signal of the monitoring unit and realizes the starting/stopping of the oil source starting cabinet; the hydraulic source control unit also has a hydraulic locking circuit.
Preferably, the hydraulic source comprises a sub-hydraulic source, a distributor and a connecting pipeline, wherein the sub-hydraulic source is connected with the swing platform through the connecting pipeline and the distributor, and provides hydraulic oil with corresponding pressure and flow for an actuator of the swing platform to drive the actuator to act.
Preferably, the swing table further comprises an upper platform, an upper connecting hinge, a lower connecting hinge and a base, one end of the actuator is connected with the upper platform through the upper connecting hinge, and the other end of the actuator is connected with the base through the lower connecting hinge; the actuator is a hydraulic cylinder provided with a pressure sensor and a displacement sensor, a servo valve is arranged on the hydraulic cylinder, connecting seats are respectively arranged at two ends of the hydraulic cylinder, and the connecting seats are connected with an upper connecting hinge or a lower connecting hinge.
Preferably, the upper connecting hinge comprises an upper shell and an upper connecting hinge main body, wherein the upper shell is connected with the upper platform, the upper shell is connected with the upper connecting hinge main body, an included angle of 45 degrees is formed between the upper shell and the upper connecting hinge main body, and the upper connecting hinge main body comprises a rear end cover I, an upper hinge shaft, a front end cover I, a pin shaft locking nut, connecting double lugs, an upper hinge pin shaft, a pin shaft end cover, a tapered roller bearing and a hinge shaft locking nut; the upper hinge shaft is respectively connected with a front end cover I and a rear end cover I, a tapered roller bearing is arranged at the joint of the upper hinge shaft and the front end cover I, and a pin shaft lock nut is arranged at the joint of the upper hinge shaft and the rear end cover; one end of the upper hinge shaft is connected with the connecting double ears through a pin shaft locking nut, and the connecting double ears are provided with an upper hinge pin shaft and a pin shaft end cover; the lower connecting hinge comprises a lower shell and a lower connecting hinge main body, the lower connecting hinge main body is connected with the base through the lower shell, and the lower connecting hinge main body comprises a rear end cover II, a lower hinge shaft, a front end cover II, a lower hinge pin shaft, a double-earring, a rolling bearing I, a rolling bearing II and a rolling bearing III; the lower hinge shaft is respectively connected with a front end cover II and a rear end cover II, a rolling bearing II is arranged at the position where the lower hinge shaft is connected with the front end cover II, and a rolling bearing III is arranged at the position where the lower hinge shaft is connected with the rear end cover II; one end of the lower hinge shaft is connected with a double-lug ring, and a lower hinge pin shaft and a first rolling bearing are arranged between the lower hinge shaft and the double-lug ring.
Preferably, the first-order natural frequency of the upper platform is 91.57HZ, the second-order natural frequency is 122.83HZ, the third-order natural frequency is 153.83Hz, the maximum stress is 23.28MPa, and the maximum displacement is 0.1815mm.
Preferably, the radius Ra of the upper hinge circle of the swing platform is 1300mm, the radius Rb of the lower hinge circle is 2000mm, the distance da between the adjacent upper hinge is 320mm, the distance db between the adjacent lower hinge is 400mm, and the length L2 of the actuator is 2700mm when the swing platform is in the middle position; rated flow of the servo valve is 250l/min under the pressure drop of the 7MPa valve; the piston area of the hydraulic cylinder is 4.9cm 2 。
Preferably, the protection unit is further divided into three layers of protection, namely a first layer of protection unit, a first layer of protection unit and a third layer of protection unit; the first layer protection unit is used for detecting and processing the validity of the system input; the second layer protection unit is used for protecting the logic of the system and comprises logic interlocking, information prompt, alarm and emergency treatment measures; the third layer protection unit is used for identifying the type, form and processing method of the system fault, and the fault type comprises overrun fault, contact fault and logic fault.
Preferably, the monitoring unit further comprises a signal generator for outputting waveforms to control the movement of the swing table, and a display panel for realizing man-machine interaction, wherein the display panel is used for displaying the movement state of the swing table and performing movement setting, and comprises a hydraulic source operation page, a movement setting page and a movement state display page.
The beneficial effects of the invention are as follows: according to the control system of the six-degree-of-freedom swinging platform, the monitoring unit receives control instructions of operators, controls the hydraulic source control unit to perform oil pressure control on the actuator of the swinging platform, enables the swinging platform to be driven by the actuator to complete various movements, monitors the working state of the swinging platform through the servo control unit and achieves closed loop feedback control, and can complete various single-degree-of-freedom static movements, single-degree-of-freedom dynamic movements and various combined movements specified by technical requirements.
Determining the working pressure of the control system, the piston area of the hydraulic cylinder and the rated flow of the servo valve according to the speed and the stress condition of the actuator, and determining the radius R of the upper hinge circle a Radius R of lower hinge circle b Distance d between adjacent hinges of upper hinge a Distance d between adjacent hinges of lower hinge b Length L of actuator when the platform is in neutral position 2 The length makes the actuator driving capability curve envelop the load motion track curve and the curve is tangent, so that the power of the control system is minimized, but the actuator driving capability curve and the load motion track curve may not be completely tangent due to the standard series problems of the servo valve and the hydraulic cylinder, so that the driving system has a certain design allowance.
Detailed Description
Example 1
As shown in fig. 1 and 2, a control system of a six-degree-of-freedom swing table comprises a hydraulic source control unit, a monitoring unit and a servo control unit, wherein the monitoring unit is respectively in communication connection with the hydraulic source control unit and the servo control unit. The monitoring unit receives control instructions of operators, controls the hydraulic source control unit to control oil pressure of the actuator 3 of the swinging platform, enables the swinging platform to be driven by the actuator 3 to complete various movements, monitors the working state of the swinging platform through the servo control unit and achieves closed-loop feedback control.
Furthermore, the monitoring unit and the servo control unit realize communication through Ethernet, and the monitoring unit and the hydraulic source control unit realize communication through an RS485 bus.
As shown in fig. 2, specifically, the monitoring unit receives a control instruction of an operator, issues the control instruction to the servo control unit through the ethernet, issues the control instruction to the hydraulic source control unit through the RS485 bus, detects the motion state of the swing table in real time through the ethernet, and detects the working state of the hydraulic source control unit in real time through the RS485 bus.
Referring to fig. 2, the servo control unit is integrated in a servo control cabinet and includes a servo controller, a signal conditioning unit, and a UPS power source. The servo control unit is used for realizing starting/stopping, motion control and motion state monitoring of the control system.
The servo control unit is used for acquiring displacement signals and pressure signals of the actuator 3 in real time, and specifically comprises the step of acquiring pressure signals of upper cavity pressure and lower cavity pressure of the actuator 3, the step of acquiring displacement signals of cylinder displacement and valve core displacement, and meanwhile, the servo controller controls the servo valve 302 through the signal conditioning unit, so that the actuator 3 is controlled to move, and the swing table is controlled to perform real-time closed-loop movement and logic control.
Furthermore, according to the use requirement, the first conditioning plate to the sixth conditioning plate are arranged in the signal conditioning unit, and the signal acquisition or transmission is carried out through the first conditioning plate to the sixth conditioning plate, so that the control of the servo controller on the actuator 3 is realized.
In addition, in order to realize the signal exchange between the control system and the user computer system, the optical fiber reflection memory card is pre-installed on the servo controller, so that the data information transmitted by the user can be received in real time, and the function expansion is facilitated.
Referring to fig. 2, the hydraulic source control unit is integrated in a PLC control cabinet, and includes a hydraulic control cabinet, an oil source starting cabinet, and a dc regulated power supply. The hydraulic source control unit is used for controlling the starting/stopping, pressurizing/unloading of the hydraulic source and the logic protection of the hydraulic source system. In addition, the hydraulic source control unit is provided with a hydraulic locking loop, so that the swing table can keep any pose static in the working range. The main function of the hydraulic locking circuit is to lock the hydraulic pressure, and the specific circuit structure is designed according to the required hydraulic passage, and is not particularly limited herein.
The hydraulic source comprises a sub-hydraulic source, a distributor and a connecting pipeline, wherein the sub-hydraulic source is connected with the swing platform through the connecting pipeline and the distributor, and the hydraulic source timely provides hydraulic oil with certain pressure and flow for the actuator 3 of the swing platform, so that the actuator 3 is driven to act.
In a specific embodiment, the selectable hydraulic source parameters are: 21MPa system oil supply pressure, 448L/min oil source average flow, 931L/min load peak flow, and 80L accumulator volume. The specification parameters of the sub-hydraulic sources may be selected according to actual use requirements, and are not particularly limited herein.
The distributor is used for realizing flow distribution of hydraulic oil in each pipeline passage and comprises a main distributor and a sub-distributor, and in the embodiment, the main distributor is provided with a main oil filter with the filtering precision of 3 mu, the rated flow of the main distributor is 1000L/min, and the main distributor is provided with an unloading function and an oil temperature and oil pressure online detection function; the sub-distributor is provided with an energy accumulator and a sub-oil filter, the nominal volume of the energy accumulator is 80 liters, instantaneous large-flow oil supply can be realized, the filtering precision of the sub-oil filter is 3 mu, the main distributor and the sub-distributor can respectively supply oil for the pilot stage of the three-stage servo valve, and the main oil filter and the sub-oil filter are respectively provided with a pressure switch to monitor the working state of each oil filter.
The connecting pipeline is laid according to the flow rate and the working pressure of the hydraulic oil, and a stop valve is arranged at the joint of the sub hydraulic source and the main distributor, so that the maintenance is convenient.
Referring to fig. 3, the swing table includes an upper platform 1, an upper connecting hinge 2, an actuator 3, a lower connecting hinge 4 and a base 5, wherein one end of the actuator 3 is connected with the upper platform 1 through the upper connecting hinge 2, and the other end is connected with the base 5 through the lower connecting hinge 4.
Referring to fig. 4, the actuator 3 is a hydraulic cylinder 301 configured with a pressure sensor and a displacement sensor, a servo valve 302 is provided on the hydraulic cylinder 301, and connecting seats 303 are respectively mounted on two ends of the hydraulic cylinder 301, and the connecting seats 303 are connected with the upper connecting hinge 2 or the lower connecting hinge 3.
The actuator 3 is used as a driving piece of the swinging platform and drives the upper platform 1 to perform corresponding actions under the action of the servo control unit. In order to achieve a six degree of freedom adjustment of the rocking stage, the actuators 3 are arranged in six, and a compound motion of the rocking stage is achieved by a coordinated motion of the six actuators 3.
The hydraulic cylinder 301 is a single-rod asymmetric cylinder, a built-in displacement sensor is coaxially arranged in a full-stroke manner, the required movement is controlled by the servo valve 302, and the piston area of the hydraulic cylinder is 4.9cm 2 . The displacement sensor is used for accurately measuring the displacement of the hydraulic cylinder 301, realizing displacement feedback, and the accuracy can reach 5 mu m by adopting digital quantity output. In the embodiment, the displacement sensor adopts a hysteresis telescopic digital displacement sensor, the testing range is 0 to 950mm, the resolution is 5 mu m, the speed resolution is 0.5mm/s, the power supply voltage is 24VDC, and the output interface is in the form of CAN bus digital.
The pressure sensor is used for measuring the pressure of two cavities of the hydraulic cylinder 301, namely the upper cavity pressure and the lower cavity pressure, so that the dynamic pressure feedback correction of the control system is realized, and the characteristics of the system are improved. In this embodiment, the pressure sensor has a measurement range of 0 to 40MPa, a measurement accuracy of < + -0.5% FS, a power supply voltage of 24VDC, and an output of 4 to 20mA.
The servo valve 302 receives the instruction of the servo controller, the control of the hydraulic cylinder 301 is completed, the servo valve 302 adopts a three-stage asymmetric structure, the area ratio of the servo valve is matched with that of the hydraulic cylinder 301, and the pressure jump and cavitation are eliminated. In the embodiment, the rated flow of the three-stage electrohydraulic servo valve is 250l/min (7 MPa valve pressure drop), the maximum working pressure is 31.5MPa, the bandwidth is more than 100Hz, and the power supply voltage is 24VDC.
The hydraulic cylinder 301 is connected to the servo valve 302 via a valve block, and a hydraulic lock valve is disposed on the valve block, so that the swing table can be kept stationary in any posture.
It should be noted that: the maximum dynamic pressure applied by the load to the actuator 3 is 96.0kN, the maximum dynamic tension is 33.5kN, the maximum static pressure in the extreme position is 90.73kN, the maximum static tension in the extreme position is 55.3kN, and the thrust of 164.93kN and the 84.11kN of the actuator 3 under 21Mpa are provided.
As shown in fig. 3, 5 and 6, the upper and lower joint hinges 2 and 4 are joint hinge assemblies, and nonlinear friction and play at joints of the joint hinge assemblies adversely affect the performance of the system, so that the joint hinge assemblies are required to have advantages of large swing angle, low friction, no gap or small play.
The upper connecting hinge 2 comprises an upper shell 201 and an upper connecting hinge main body, the upper shell 201 is connected with the upper platform 1, the upper shell 201 is connected with the upper connecting hinge main body, an included angle of 45 degrees is formed between the upper shell and the upper connecting hinge main body, and the upper connecting hinge main body comprises a rear end cover I202, an upper hinge shaft 203, a front end cover I204, a pin shaft locking nut 205, a connecting double lug 206, an upper hinge pin shaft 207, a pin shaft end cover 208, a tapered roller bearing 209 and a hinge shaft locking nut 210.
The front end cover one 204 and the rear end cover one 202 are respectively connected to the upper hinge shaft 203, a tapered roller bearing 209 is configured at the connection position between the upper hinge shaft 203 and the front end cover one 204, a pin shaft lock nut 210 is configured at the connection position between the upper hinge shaft 203 and the rear end cover 202, one end of the upper hinge shaft 203 is connected to the connection double ears 206 through the pin shaft lock nut 205, and an upper hinge pin shaft 207 and a pin shaft end cover 208 are configured on the connection double ears 206.
The lower connecting hinge 4 comprises a lower shell 401 and a lower connecting hinge body, wherein the lower connecting hinge body is connected with the base 5 through the lower shell 401, and the lower connecting hinge body comprises a second rear end cover 402, a second lower hinge shaft 403, a second front end cover 404, a second lower hinge pin shaft 405, a double-lug ring 406, a first rolling bearing 407, a second rolling bearing 408 and a third rolling bearing 409.
The lower hinge shaft 403 is respectively connected with a front end cover II 404 and a rear end cover II 402, a rolling bearing II 408 is arranged at the position where the lower hinge shaft 403 is connected with the front end cover II 404, a rolling bearing III 409 is arranged at the position where the lower hinge shaft 403 is connected with the rear end cover II 402, one end of the lower hinge shaft 403 is connected with a double-lug ring 406, and a lower hinge pin shaft 405 and a rolling bearing I407 are arranged between the lower hinge shaft 403 and the double-lug ring 406.
As shown in fig. 3, the upper platform 1 comprises a bearing table and an annular seat ring, the annular seat ring is connected with the bearing table and is positioned below the bearing table, and the surfaces of the swinging tables are subjected to corrosion prevention and rust prevention. The bearing platform is used for installing a load, the load is directly fixed above the upper platform 1, and the upper platform 1 acts along with the driving of the actuator 3 under the driving of the actuator 3, so that the load is driven to perform corresponding motion simulation.
In addition, the design of the upper platform 1 needs to meet the interface requirement of a user load, a plurality of reserved interfaces are configured, a through hole is reserved in the center of the upper platform 1, the installation and the positioning of the load and the wiring of an electric circuit on the load are facilitated, and meanwhile, the upper platform 1 has enough rigidity and smaller deformation to meet the requirements of static and dynamic characteristics of a user test.
In this embodiment, as shown in fig. 7 to 16, the geometric dimensions of the upper platform 1 are 4500mm×4500mm×200mm, and the weight is <3000kg; the first-order natural frequency is 91.57HZ, the second-order natural frequency is 122.83HZ, the third-order natural frequency is 153.83Hz, the maximum stress is 23.28MPa, the maximum displacement is 0.1815mm, the resonance point can be avoided through the higher structure natural frequency, and the safety of the swing table is improved.
The maximum load of the swinging table is 10 tons, the gravity center height H is less than or equal to 1m (the distance from the upper surface of the platform), and the gravity center eccentricity L is less than or equal to 0.5m.
As shown in fig. 17 and 18, the structural parameters of the swing table include the radius R of the upper hinge circle a Radius R of lower hinge circle b When the swing table is in the middle position, the distance L between the upper hinge point and the lower hinge point of the actuator 2 Distance d between adjacent hinges of upper hinge a Distance d between adjacent hinges of lower hinge b 。
The motion and dynamics of the rocking platform are determined by the five structural parameters. Therefore, in the design of the swing table, the five structural parameters need to be optimized, so that the swing table has the advantages of no interference in the motion process, high enough natural frequency of the structure, low power, low operation cost and the like.
On the basis of ensuring the normal operation of the swing table, a control system with smaller power is provided as an important problem in the design of the six-degree-of-freedom swing table.
As shown in fig. 19, the curve 1 located below is a load motion track curve, the curve 2 located above is a driving capability curve of the actuator 3, the curve located in the middle is an X-axis, a Y-axis and a Z-axis, and by comparing the curves 1 and 2, the curve 2 is considered to envelope the curve 1, and when the curve 2 is tangential to the curve 1, the servo control unit and the hydraulic source control unit realize the best load matching, but because of the standard series of the servo valve and the hydraulic cylinder in the prior art, the curves may not be completely tangential in the figure, and the driving system has a certain design margin.
According to the body coordinate system ozz shown in fig. 24, as shown in fig. 20, the load matching of the driving system when the swing table rotates around X, Y, Z to the maximum acceleration is shown, in the figure, the matching is shown when the swing table rotates around the X axis, the Y axis and the Z axis in order from left to right, as shown in fig. 21, the load matching of the driving system when the swing table translates along X, Y, Z to the maximum acceleration is shown, in the figure, the matching is shown when the swing table translates along the X axis, the Y axis and the Z axis in order from left to right. Through the optimal design, the structural parameters of the swing table are finally determined as follows:
radius R of upper hinge circle a 1300mm
Radius of lower hinge circle R b 2000mm
Distance d between adjacent upper hinges a 320mm
Distance d between adjacent hinges of lower hinge b 400mm
Length L of actuator when the platform is in neutral position 2 :2700mm
Working stroke: 0.901m < -0.432-0.469 m
Buffer length: 2X 20mm
Total travel: 0.941m < -0.452-0.489 > m
Minimum height of motion system (upper and lower hinge plane spacing): 1.7021m
Height in the motion system (upper and lower hinge plane spacing): 2.2658m
High-level height (upper and lower hinge plane spacing) of the motion system: 2.8308m
As shown in fig. 22, the radial maximum force of the upper joint hinge 2 is 72.103KN, and the axial maximum force is 50.636KN; as shown in fig. 23, the lower joint hinge 4 has a radial maximum force of 78.562KN and an axial maximum force of 39.885KN.
The maximum stress condition of the foundation is shown in Table 1
TABLE 1
As shown in fig. 24 and 25, in order to describe the spatial movement of the rocking platform, a movement coordinate system of the rocking platform is established, and specifically, a body coordinate system ozz and a static coordinate system O 'X' Y 'Z' are provided.
The comprehensive center of mass of the upper platform 1 and the load is selected as the origin of coordinates of the coordinate system OXYZ, the advancing direction of the load device is the X direction, the normal direction of the advancing plane pointing downwards is the Z direction, and the Y direction of the coordinate system is determined according to the right-hand rule. The static coordinate system O 'X' Y 'Z' is fixed on the ground, and the static coordinate system O 'X' Y 'Z' is completely overlapped with the body coordinate system OXYZ when the static coordinate system O 'X' Y 'Z' is at the initial position.
As shown in fig. 24 and 25, A1 to A6 show the joint hinge points of the actuator 3 and the upper joint hinge 2; b1 to B6 represent connection hinge points of the actuator 3 and the lower connection hinge 4; a1B1 to A6B6 represent first to sixth actuators; OM denotes a table centroid; o represents the integrated centroid. Wherein, the serial number of each actuator 3 corresponds to the serial number of the connecting hinge point.
The state motion of the swinging table comprises a tilting state, a swinging state, a single degree of freedom state and compound motion, wherein the technical parameters of the tilting state motion of the swinging table are shown in table 2.
Table 2 the rocking state movement parameters of the rocking table are shown in table 3.
Degree of freedom
|
Displacement of
|
Speed of speed
|
Acceleration of
|
Roll-to-roll
|
±25°
|
±24°/s
|
±140°/s 2 |
Pitching machine
|
±20°
|
±20°/s
|
±350°/s 2 |
Bow sway
|
±15°
|
±15°/s
|
±200°/s 2 |
Swing longitudinally
|
±0.50m
|
±0.30m/s
|
±0.6g
|
Lateral swinging
|
±0.50m
|
±0.30m/s
|
±0.6g
|
Heave
|
±0.40m
|
±0.30m/s
|
±1.0g |
Table 3 single degree of freedom state motion parameters of the rocking table are shown in table 4.
Degree of freedom
|
Displacement of
|
Speed of speed
|
Acceleration of
|
Roll-to-roll
|
±25°
|
±24°/s
|
±140°/s 2 |
Pitching machine
|
±20°
|
±20°/s
|
±350°/s 2 |
Bow sway
|
±15°
|
±15°/s
|
±200°/s 2 |
Swing longitudinally
|
±0.50m
|
±0.30m/s
|
±0.6g
|
Lateral swinging
|
±0.50m
|
±0.30m/s
|
±0.6g
|
Heave
|
±0.40m
|
±0.30m/s
|
±1.0g |
Table 4 the composite motion parameters of the rocking platform are shown in table 5.
Degree of freedom
|
Displacement of
|
Cycle time
|
Roll-to-roll
|
±10°
|
4s
|
Pitching machine
|
±8°
|
5s
|
Bow sway
|
±7°
|
6s
|
Heave
|
±0.15m
|
5s |
TABLE 5
It is mainly noted that the wobble waveform can wobble according to a sine spectrum type, a third harmonic and a random real record spectrum. The swinging table has the function of keeping static at any position and any posture in the working range, and can meet the requirement of static debugging of test equipment under the condition of closing an oil source.
The corresponding relation between the pose of the swinging table and the definition of the coordinate system is as follows:
longitudinal oscillation-translation along the X-axis
Lateral oscillation-translation along the Y-axis
Heave-translation along the Z-axis
Roll-rotate about X-axis
Pitching-rotation about the Y-axis
Yaw-rotation about the Z-axis
The precision of the rocking platform is set as follows:
(1) Static accuracy
a) Three line coordinates static positioning accuracy: the positioning error is less than 5% of the maximum amplitude;
b) Static positioning precision of three attitude angles: the positioning error is less than 5% of the maximum amplitude.
(2) Dynamic accuracy
a) Frequency characteristics: the system bandwidth is 4Hz, the amplitude attenuation is less than 3dB, the phase lag is less than 90 degrees, and the overshoot is less than or equal to 20%;
b) Sinusoidal waveform distortion degree: when the frequency is less than or equal to 1Hz, the frequency is less than 5 percent; less than 10% at a frequency >1 Hz;
as shown in fig. 26, the swing table operates on the principle: firstly, a user inputs expected motion parameters, and the required swing platform pose is realized through the motion parameters. If the motion is sinusoidal in the X direction, the motion parameters are transmitted to a servo controller, and the servo controller calculates the motion parameters of the six actuators 3 and the displacement of the hydraulic cylinder 301 through inverse kinematics.
Then, the servo controller outputs the motion parameters of the six actuators 3 to the servo driving system, and the servo driving system realizes closed-loop position control of the six hydraulic cylinders 301 according to the displacement amount to reach the required displacement amount, so that the swing table reaches the expected motion gesture.
The control system of the six-degree-of-freedom swinging platform has a servo control function and an amplitude-phase control function, can finish various single-degree-of-freedom static, single-degree-of-freedom dynamic and various combined movements specified by technical requirements, can swing according to sine spectrum types, third harmonic waves and random real record spectrums, can utilize waveform control platform bodies generated by self signal generators to do corresponding movements, and can also utilize external input to do corresponding movements.
Example two
The structure of this embodiment is substantially the same as that in the first embodiment, except that: the embodiment also comprises a protection unit, which comprises three layers of protection, and is specifically divided into a first layer of protection unit, a first layer of protection unit and a third layer of protection unit.
The first layer protection unit is used for detecting and processing the validity of the system input. For a six degree of freedom swing, not all movements are possible due to the limitations of the system capabilities. The control system software can automatically detect the validity of the input of the user. For those movements that cannot be achieved, an overrun cue is given, and the overrun input is not performed. When the user inputs the exceeding position and speed limiting values, an overrun type prompt is given out from the running information of the software operation interface.
The second layer protection unit is used for protecting the logic of the system, and comprises measures such as logic interlocking, information prompt, alarm, emergency treatment and the like. In order to further prevent the damage to the system caused by misoperation of the user, the software is classified according to the importance of the operation, and management authority is set for the user. Users of different administrative rights may use different levels of operation. Generally, the steps can be classified from low to high: an operator stage, a control stage, a calibration stage, and a configuration stage.
The third layer protection unit is used for identifying the type, form and processing method of the system fault; including overrun faults, contact faults, logic faults, and other faults. The categories of system faults include overrun faults, contact faults, logic faults, and other faults.
The overrun fault comprises overrun of the motion speed of the actuator; the pressure of the actuator exceeds the limit; the position of the actuator exceeds the limit; a condition associated with the hydraulic source overruns; controlling the system error to exceed the limit; the position, speed and acceleration control instructions of the actuator are overrun.
The contact faults include displacement sensor plug contact faults; servo valve plug contact failure, pressure sensor plug contact failure.
The logic faults comprise communication failures of the monitoring unit; the servo controller does not respond; a power failure; failure of the sensor; the logic fault of the hydraulic control cabinet and the communication of the PLC are not responded.
Other faults include displacement sensor signal overrun; pressure transient faults; the control software runs over time.
The control system classifies fault processing into three levels according to the severity of faults, and the processing levels are classified from low to high: alarm, exit, scram exit.
The alarm is not considered to be a fault, but is just a prompt to an operator, so that the current system is in a bad motion state and needs to be noticed.
When the system fails seriously, the exit function is adopted, so that the actuator 3 returns to the lowest position at a lower speed, the hydraulic pump is turned off, and the hydraulic source is depressurized.
The emergency stop exit mode mainly comprises the steps of arranging emergency stop buttons at different positions of a control room, an experimental hall and the like, and enabling an operator to return the actuator 3 to the lowest position at a lower speed through the emergency stop buttons when an emergency fault occurs or the control system cannot work normally.
In addition, since the servo valve 302 is controlled by the servo controller, once the servo controller crashes, the servo valve 302 will lose control, and in order to avoid such a runaway condition, a hardware watchdog function is designed.
As shown in fig. 27, the function of the hardware watchdog is to detect the state of the servo controller in real time, and once a fault state is detected, an enabling signal is sent out to enable the servo valve to be in an emergency exit state, and the swing table is dropped back at a safe speed, so that the safety protection of the system is realized.
Before the control system operates, the control system firstly performs starting-up self-checking, wherein the starting-up self-checking content comprises checking of control system hardware, detection of various sensor states and detection of states of control valves. And detecting the watchdog state, judging whether the watchdog state is normal, if so, allowing the system to start, and if the watchdog abnormality is detected, not starting the system.
Further, in order to make the hydraulic system operate safely and reliably, a safety design of a hydraulic source is performed, and the hydraulic source mainly comprises: the hydraulic oil temperature control system comprises overtemperature protection, pressure fault protection and oil tank liquid level low fault protection, wherein the overtemperature protection detects the hydraulic oil temperature of a hydraulic source high-pressure pipeline by using a temperature sensor, and if the temperature is too high, a main pump unit stops.
The pressure fault protection means that when the pressure of the hydraulic source is too high, the swing table is withdrawn, and the main pump unit stops; and stopping or retracting the platform when the oil pressure is too low, and stopping the main pump unit.
When the liquid level of the oil tank is low, the fault protection means that the liquid level of the hydraulic source is low, the swing table stops moving and falls back to the lowest position, and the main pump unit stops.
The hydraulic source also has an unloading function, the main pump unit is stopped, and the unloading valve is opened, so that the unloading of the hydraulic source energy accumulator is realized.
For the swinging platform, besides ensuring the sufficient rigidity and strength, the swinging platform can be ensured to be in any possible motion (including normal motion and fault state), interference collision cannot occur between mechanical parts, and the full-digital prototype system can be utilized for carrying out full interference check on the swinging platform to adjust the structure of the swinging platform to be in a non-interference state.
The natural frequencies of the six degrees of freedom of the swinging table are respectively as follows: longitudinal swing 4.99Hz; swing transversely by 5.15Hz; lifting by 12.37Hz; roll 9.78Hz; pitching 7.9Hz; the bow is 6.8Hz. The swing platform is only allowed to work below 4Hz, and the working frequency is ensured to be lower than the natural frequency so as not to cause resonance, thereby ensuring the safety of the swing platform.
Example III
The structure of this embodiment is substantially the same as that in the first embodiment, except that: in this embodiment, the monitoring unit further includes a display panel for implementing man-machine interaction, and displays, processes and stores parameters of the running state of the swing platform, so that the running state of the swing platform can be displayed, and the implementation of movement setting is facilitated.
Specifically, the display panel comprises a hydraulic source operation page, a motion setting page and a motion state display page, wherein a user can monitor the running state of the whole hydraulic source through the hydraulic source operation page, and the operations of starting/stopping control, pressurization/pressure relief and the like of the hydraulic source are realized. In addition, the hydraulic pressure source has both automatic control and manual control, and in the automatic control mode, it is possible to select to automatically start/stop the entire hydraulic pressure source or to start/stop one sub-hydraulic pressure source alone. In the manual mode, the user can realize the start/stop control of the hydraulic source according to a certain operation sequence as required.
The motion setting page is mainly used for completing motion waveform selection and motion parameter setting of the swinging platform, and amplitude, frequency and phase can be set for sinusoidal signals.
The motion state display page mainly comprises real-time display and historical data display of the swinging table state. The user can select the content to be displayed. For example, the swing table posture, the displacement setting of the actuator 3, the displacement feedback of the actuator 3, the upper chamber pressure, the lower chamber pressure, etc. may be displayed.
The monitoring unit also comprises a signal generator for outputting waveforms to control the movement of the swinging platform, so that the control system can swing according to the sine spectrum type, the third harmonic or the random real record spectrum, and the waveform generated by the signal generator can be used for controlling the swinging platform to do corresponding movement, and the external input can be used for controlling the platform body to do corresponding movement.
The foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.