Four-sensor formula scrambler
Affiliated technical field
The invention belongs to the photoelectric sense technology field, but specifically a kind of magnetic code circuit of measurement axis rotational angle.
Background technology
The rotation photoelectric encoder is that light harvesting, mechanical, electrical technology are in rotating speed, the displacement transducer of one.When the scrambler axle drives the code-disc rotation, logical, the dark areas of the light transmission code-disc that light-emitting component sends (perhaps round grating and indication grating) are divided into interrupted light and are received the element reception, produce initialize signal, this signal after follow-up processing of circuit, output pulse signal.
Photoelectric encoder has experienced the evolution from the increment type to the absolute type.
During the rotation of incremental encoder axle, drive the grating disc spins, the light that light-emitting component sends is cut into interrupted light by the slit of grating dish, indication grating and is received element and receives, output has corresponding pulse signal, and the increase and decrease of its sense of rotation and number of pulses needs to realize by the direction judgment circuit sum counter at rear portion.Its counting starting point can be set arbitrarily, and can realize infinitely adding up and measuring of multi-turn.The Z signal of a pulse can also sending revolution is as the reference mechanical zero.Fixing when umber of pulse, and when need improving resolution, can utilize A, the B two paths of signals of 90 ° of phase differential, frequency multiplication is carried out in former pulse.Increment of rotation formula scrambler is the output pulse when rotating, and knows its position by counting equipment, and is motionless or when having a power failure when scrambler, relies on the memory internal of counting equipment to remember the position.Like this, after having a power failure, scrambler can not have any moving, when incoming call work, in the scrambler output pulse process, can not have and disturb and pulse-losing, not so, will be offset the zero point of counting equipment memory, and the amount of this skew is unable to find out, and only vicious production result just can know after occurring.The method that solves is to increase reference point, and scrambler is every through reference point, and the into memory area of counting equipment is revised in the reference position.Before reference point, be the accuracy that can not guarantee the position.For this reason, in industry control, just there is each operation to look for reference point earlier, methods such as start small change.Such as, the location of printer scanner is exactly the incremental encoder principle of usefulness, each start, and we can both hear a burst of sound of Pi mile crack, it is just worked then looking for reference zero.The numerically-controlled machine of utilization incremental encoder in the control loop must return zero earlier after the start with each, could correct execution processing instruction.Such method is cumbersome to some industry control project, does not even allow start small change (will know accurate position after the start), so the appearance of absolute encoder has just been arranged.
During the rotation of absolute optical encoder axle, output and position be code (scale-of-two, binary-coded decimal etc.) one to one.Can differentiate positive dirction, displacement from the code size variation, and residing absolute position, need not direction judgment circuit.It has an absolute zero position code, after power failure or shutdown, when start remeasures again, still can read the code that has a power failure or shut down the position exactly, and find the zero-bit code exactly.Absolute encoder is divided from measurement range, and two types of individual pen and multi-turns are arranged.Absolute encoder is to represent the position, angle of axle by reading pattern on the code-wheel, the coded graphics of Fig. 1-2 for simplifying, and actual code-disc is to cut apart more labyrinth.Many roads groove is arranged on the optical code disk, and the per pass groove is from the inside to surface successively with 2 lines, 4 lines, 8 lines, 16 lines ... layout like this, in each position of scrambler, by reading logical (among the figure white part), dark (the deceiving) of per pass groove, obtains one group from 2
0To 2
N-12 unique scale codings, this just is called n position absolute encoder.The coded system of absolute encoder has pure binary coding and reflected code etc.Absolute encoder has determined the uniqueness of each position by mechanical location, and it need not power-failure memory, need not to look for reference point, and need not count always, when needs location aware, when just goes to read its position.Like this, the reliability of the noiseproof feature of scrambler, data has improved greatly.Because absolute encoder is better than incremental encoder significantly aspect the location, be applied to angle, linear measure longimetry and positioning control in the various industrial systems more and more.There are some shortcomings that are difficult to overcome in photoelectric encoder, the less precision of cube higher occasion, be difficult to adhere to specification, and manufacturing cost is higher, photoelectric encoder will be in a disadvantageous position in market competition.
At these shortcomings of photoelectric encoder, the development of magnetic encoder in recent years launches just gradually.
Sensor stator and rotor are made with pure iron, and fixed permanent magnet on the stator forms magnetic circuit system.Mill tooth and groove equably on the stator annular end face relative with rotor, the two teeth groove number equates that rotor tightens up with axle, and axle is connected with tested revolving shaft.Axle drives rotor rotation, when rotor tooth is relative with stator tooth, and air gap minimum, whole magnetic circuit magnetic flux maximum; Magnetic flux minimum when tooth is relative with groove.Produce pulse voltage output with coil or magneto sensor induction flux change, change frequency is directly proportional with rotating speed.This type of scrambler survey rotating ratio is more common, and it is very low to be used for surveying the rotational angle precision, can only realize increment output.
Summary of the invention
The existing encoder anti-interference is poor, precision is low in order to overcome, processing cost is high, the restricted technical deficiency of the scope of application, the invention provides a kind of four-sensor formula scrambler, utilization is fixed on magneto sensor impression on the stator circumference and is fixed on magnet steel on the axle and rotates the change of magnetic field strength that causes and export the voltage signal that out of phase changes, judge the axle rotational angle with magnitude of voltage, this type of sensor can be realized the measurement of high-precision velocity of rotation and absolute position.
The technical solution adopted for the present invention to solve the technical problems is: be set in qually spaced on the same circumference at four magnetic sensors on the quadrant position, non-conterminous two magnetic sensors (211), (213) output signal (A1), (A2) connect differential amplifier (1), two other non-conterminous magnetic sensor (212), (214) output signal (B1), (B2) connect differential amplifier (2), differential amplifier (1) output signal (A0) connects AD converter (3), the output signal (Ad) of AD converter (3) connects multiplier (5), differential amplifier (2) output signal (B0) connects AD converter (4), the output signal (Bd) of AD converter (4) connects multiplier (6), coefficient correction device (10) output signal (K) connects the input end of multiplier (5) and multiplier (6), the output signal (A) of multiplier (5) and multiplier (6), (B) engage the input end of grow up to be a useful person (7), the output signal (D) of compositor (7) is as the input signal end of first memory (8) and second memory (9), compositor (7) output signal (R1) and second memory output signal (R0) connect the input end of coefficient correction device (10), and the output signal of first memory connects angle transverter (11).
The coefficient correction device is connected in series successively by subtracter (101), divider (102), α multiplier (-icator) (103) and totalizer (104), another input end of divider (102) is connected with another input end of subtracter (101), the output signal (R0) of this input termination second memory (9), another input end of subtracter (101) engages (7) output signal (R1) of growing up to be a useful person.
The invention has the beneficial effects as follows, utilization is fixed on magneto sensor impression on the stator circumference and is fixed on magnet steel on the axle and rotates the change of magnetic field strength that causes and export the voltage signal that out of phase changes, judge the axle rotational angle with magnitude of voltage, thereby realize the measurement of high-precision velocity of rotation and absolute position.
Description of drawings
The invention will be further described below in conjunction with drawings and Examples.
Fig. 1 is a schematic block circuit diagram of the present invention.
Fig. 2 is the circuit theory diagrams of coefficient correction device among Fig. 1 of the present invention.
1. differential amplifiers among the figure, 2. differential amplifier, 3.AD converter, 4.AD converter, 5. multiplier, 6. multiplier, 7. combining amplifier, 8. first memory, 9. second memory, 10. coefficient correction device, 11. angle transverters, 101. subtracters, 102. divider 103. α multiplier (-icator)s, 104. totalizers, 211. sensors, 212. sensor, 213. sensor, 214. sensors, A1. sensor output signal, A2. sensor output signal, B1. sensor output signal, B2. sensor output signal, A0. differential amplifier output signal, B0. differential amplifier output signal, Ad.AD converter output signal, Bd.AD converter output signal, A. multiplier output signal, B. multiplier output signal, D. compositor output signal, R0. second memory output signal, R1. compositor output signal, K. coefficient correction device output signal, J0 first memory output signal.
Embodiment
In Fig. 1, be set in qually spaced on the same circumference at four magnetic sensors on the quadrant position, non-conterminous two magnetic sensors (211), (213) output signal (A1), (A2) connect differential amplifier (1), two other non-conterminous magnetic sensor (212), (214) output signal (B1), (B2) connect differential amplifier (2), differential amplifier (1) output signal (A0) connects AD converter (3), the output signal (Ad) of AD converter (3) connects multiplier (5), differential amplifier (2) output signal (B0) connects AD converter (4), the output signal (Bd) of AD converter (4) connects multiplier (6), coefficient correction device (10) output signal (K) connects the input end of multiplier (5) and multiplier (6), the output signal (A) of multiplier (5) and multiplier (6), (B) engage the input end of grow up to be a useful person (7), the output signal (D) of compositor (7) is as the input end of first memory (8) and second memory (9), compositor (7) output signal R1 and second memory output signal R0 connect the input end of coefficient correction device (10), and the output signal of first memory connects angle transverter (11).
Among the present invention
X_I represents the I position of data X; It is I bit position from left to right at data X.The 0th of data X the Far Left wherein at data X; The I position
When data X was signed number, the 0th of data X was its sign bit.
X_0=1 represents that data X is a negative; X_0=0 represents that data X is a positive number.
X_D represents the value bit of data X, on the right of the sign bit of data X and near sign bit.
{ X_a; X_b; X_c} represents the data X that forms by Fig. 6 mode.
The output of compositor of the present invention (7) is in the following manner:
If (A_D>=B_D)
D={A_0;B_0;B_D}
R1=A
Otherwise
D={A_0;B_0;A_D}
R1=B
In Fig. 2, coefficient correction device (10) is by subtracter (101), divider (102), α multiplier (-icator) (103) and totalizer (104) are connected in series successively and form, the output signal (R0) of second memory (9) and the output signal (R1) of compositor (7) connect two input ends of subtracter (101), the output signal (E1) of subtracter (101) connects divider (102) input end, another input end of divider (102) also joins with the output signal (R0) of second memory (9), the output signal (E2) of divider (102) connects α multiplier (-icator) (103), the output signal (E3) of α multiplier (-icator) (103) connects the input end of totalizer (104), and the output signal of totalizer (104) is the signal input part that the output signal (K) of coefficient correction device (10) connects multiplier (5) and multiplier (6) respectively.
The present invention form coefficient correction device (10) subtracter (101), divider (102), α multiplier (-icator) (103) and totalizer (104) output in the following manner:
E1=R0-R1
E2=E1/R0
0<α<1
E3=αE2
K(i)=K(i-1)+E3;i=0,1,2...K(0)=1
I is a sampling sequence number, is 0 when beginning to sample
The present invention's differential amplifier 1 described above, differential amplifier 2, AD converter 3, AD converter 4, multiplier 5, multiplier 6, combining amplifier 7, first memory 8, second memory 9, coefficient correction device 10, angle transverter 11, subtracter 101, divider 102, α multiplier (-icator) 103, totalizer 104, magnetic sensor 211, magnetic sensor 212, magnetic sensor 213, the circuit structure of magnetic sensor 214 are that this area ordinary person is known public, and this no longer is repeated in this description its structural principle.