Intelligent drive unit and method for measuring absolute position of output end of drive unit

Abstract

The application discloses an intelligent driving unit and a driving unit output absolute position measurement method, characterized by comprising a motor, a speed reducer, a motor control panel, a plurality of pairs of magnetic rings and a magnetic ring encoder, and a driving unit output absolute position measurement method. The application can adapt to various motor application scenarios and the speed reducer with high speed reduction ratio, can realize multi-turn absolute position coding of the output end, does not limit the rotation range of the output end, has relatively lower manufacturing cost, and has popularization and application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of driving motor, in particular to an intelligent driving unit and a driving unit output end absolute position measurement method. BACKGROUND

[0002] At present, a general driving motor includes a motor, a reducer and a control board, the control board is arranged at the motor end, the control board is provided with a magnetic encoder, the position of the motor shaft, the number of turns and the reduction ratio are recorded through the magnetic encoder at the motor end to calculate the position of the output end of the reducer, the disadvantage of this scheme is that after the motor power failure, the motor shaft rotates due to external force, the control board cannot obtain the initial position of the output end of the reducer, so only the relative rotation position can be obtained, and the absolute position of the output end cannot be obtained.

[0003] In order to solve this problem, the prior art adopts a double position encoder, that is, a position encoder is arranged at the motor end and the output end of the reducer, the encoder at the motor end is used for motor control, and the encoder at the output end of the reducer is used for detecting the position of the reducer, so as to obtain the absolute position of the output end of the reducer.

[0004] This scheme has the following several common types:

[0005] 1. Both ends adopt magnetic encoding chips, since the magnetic encoding chip needs to be installed at the center of the rotating shaft, after the magnetic encoders are installed at both ends, the reducer can only output from the middle position, this method will limit the rotation range of the output end to less than 360°, that is, the output end cannot rotate continuously for multiple turns, which will limit the application scene of the motor;

[0006] 2. The output end of the reducer adopts a magnetic grid encoder, the advantage of the encoder is that it is hollow and does not affect the output rotation range of the reducer shaft, but the cost of the magnetic grid encoder is relatively high;

[0007] 3. The output end of the reducer adopts a pair of magnetic ring encoders, the cost of the scheme is much lower than that of the magnetic grid encoder, but the precision is low, although the absolute position of the output end can be calculated combined with the encoder at the motor end, but it is only suitable for occasions with low reduction ratio. SUMMARY

[0008] The present application proposes an intelligent driving unit and a driving unit output end absolute position measurement method which can adapt to various motor application scenes and high reduction ratio reducers, can realize multi-turn absolute position encoding of the output end, and will not limit the rotation range of the output end, and has relatively lower manufacturing cost.

[0009] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0010] An intelligent driving unit, characterized by comprising a motor, a reducer, a motor control board, a plurality of pairs of magnetic rings and a magnetic ring encoder;

[0011] The motor is used to output the torque to drive the reducer, and a magnet is arranged on the top end of the motor shaft close to the motor control panel.

[0012] The reducer is used to convert the high-speed rotating torque output by the motor into low-speed rotating torque according to the reduction ratio and increase the torque.

[0013] The motor control panel comprises a magnetic encoding chip, a control chip and a motor driving circuit, the magnetic encoding chip is arranged above the magnet of the motor shaft, and is used to magnetically encode the real-time stroke and position signal of the magnet on the motor shaft when the motor shaft rotates, the control chip is used to solve the data signal sent by the magnetic encoding chip and the magnetic ring encoder, and the rotating stroke and real-time position of the output end of the reducer are obtained, and the motor driving circuit is used to drive the motor to complete the torque control, rotating position control, speed control and other control instructions in cooperation with the control chip.

[0014] The multiple pairs of magnetic rings are fixed to the output end of the reducer and rotate coaxially with the output end of the reducer, and the multiple pairs of magnetic rings rotate when the output end of the reducer rotates, and the multiple pairs of magnetic rings change the direction and strength of the magnetic field when rotating, and the magnetic ring encoder is provided with a magnetic ring encoding chip, which is used to monitor the magnetic signal generated by the change of the magnetic field to encode the position; the magnetic ring encoder is in communication connection with the motor control panel through signal wires, and is used to send the encoding data of the magnetic ring encoder to the control chip on the motor control panel for solving.

[0015] Further, the control chip is STM32F103R8T6.

[0016] Further, the magnetic encoding chip is AS5047.

[0017] Further, the magnetic ring encoding chip of the magnetic ring encoder is MT6818 or MT6828.

[0018] A method for measuring and calculating the absolute position of the output end of a driving unit, characterized by the following steps:

[0019] Step 1, first calculate the periodical relationship of the data of the output end of the reducer, the magnetic encoder and the magnetic ring encoder, and the corresponding formula is as follows:

[0020] Let the reduction ratio be K:1, and the angle change value α of the output end of the reducer corresponding to one revolution of the motor shaft is α=360 / K, which is equation 1;

[0021] Let the number of magnetic ring pole pairs of the magnetic ring encoder be J, and the output end angle change value β corresponding to one revolution of the magnetic ring encoder is β=360 / J, which is equation 2;

[0022] The motor end encoder and the magnetic ring encoder data coincide once after the output end changes at least γ degrees, that is, α*M=β*L=γ, where M and L are positive integers and the only common divisor is 1, and γ takes the minimum value that satisfies the equation, which is equation 3;

[0023] Step 2, in the scene with rotation limit, when the absolute position encoding of the reducer output shaft position value needs to be implemented, J and K values are selected to make γ satisfy γ≥θ, where θ is the maximum mechanical angle change value of the motor output end;

[0024] Step 3, when single-turn absolute position encoding needs to be implemented, J and K values are selected to make γ satisfy γ=360, combined with equation 1 to 3 in step 1, the equation can be obtained: (360 / K)*M=(360 / J)*L=γ=360, after simplification, M / K=L / J=1 can be obtained, where M and L are positive integers and the only common divisor is 1, that is, K and J are positive integers and the only common divisor is 1;

[0025] Step 4, when multi-turn absolute position encoding needs to be implemented, J and K values are selected to make γ satisfy γ=360*H, where H is the number of turns that need to be encoded, combined with equation 1 to 3 in step 1, the equation can be obtained: (360 / K)*M=(360 / J)*L=γ=360*H, after simplification, M / K=L / J=H can be obtained, where M and L are positive integers and the only common divisor is 1, that is, M=K*H, L=J*H, where M and L are positive integers and the only common divisor is 1, which is equation group 1, K and J take values that satisfy equation group 1;

[0026] Step 5, according to the corresponding application scenarios in steps 2 to 4, the initial position calculation formula of the drive unit output end after power failure restart can be obtained by combining the periodic relationship in step 1 as follows:

[0027] Q=N*D1+d1= [(N*D1+d1) / D2]*D2+d2

[0028] N is a positive integer that satisfies the above formula, and N

[0029] When solving, first calculate the value of N, and then calculate Q;

[0030] Wherein

[0031] D1 is the larger value of α and β (for example: α>β D1=α, otherwise D1=β);

[0032] D2 is the smaller value of α and β (for example: α<β D2=α, otherwise D2=β);

[0033] d1 is the angle value read by the D1 corresponding encoding unit;

[0034] d2 is the angle value read by the D2 corresponding encoding unit;

[0035] Q is the absolute position angle of the reducer output end;

[0036] [] represents the rounding operation, for example: [x] represents the maximum integer not greater than x;

[0037] Step 6. Obtain the dynamic position of the output end, read and calculate the position of the magnetic encoding chip or the magnetic ring encoding chip, and calculate the corresponding position increment of the output end, wherein: the output end position change angle = the magnetic encoder angle change / K, the output end position change angle = the magnetic ring encoder reading angle change / J; according to the formula: the dynamic position of the output end = the initial position + the incremental position, the dynamic position of the motor output end is calculated, and the absolute position of the driving unit output end is measured and calculated.

[0038] Further scheme is: due to the existence of the magnetic ring encoder, the magnetic encoder quantization error and the mechanical processing error, according to the data read by the encoder, there is a certain error between the output shaft true position, in the case of error can not be ignored, the calculation formula and method in step 5 are as follows:

[0039] Let the output shaft position calculated by the encoder measurement value corresponding to D1 be q1, the error be δ1, the output shaft position calculated by the encoder measurement value corresponding to D2 be q2, and the error be δ2, the following equation is established:

[0040] Q = q1-δ1 = q2-δ2

[0041] According to the above formula, the output shaft position calculation formula is as follows:

[0042] Q = N*D1+d1-δ1 = [(N*D1+d1-δ1+δ2) / D2]* D2 +d2-δ2

[0043] N is a positive integer satisfying the above formula, and N < M, N < L equation 1

[0044] F = N*D1+d1-δ1+δ2-[(N*D1+d1-δ1+δ2) / D2]* D2 -d2

[0045] N is a positive integer satisfying the above formula, and N < M, N < L equation 2

[0046] When δ 1、 When δ

[0047] When only the value range of δ 1、The value of delta 2 can be substituted into the above formula according to the highest precision in the two encoders and the possible N value, and N and -delta 1+delta 2 are taken to make F minimum, and the value of the position Q of the output shaft of the reducer containing the error term can be obtained by substituting equation 1. To obtain more accurate Q, more accurate delta can be obtained through calibration 1， The range or value of delta 2.

[0048] The beneficial effects of the present application are that the reducer can adapt to various motor application scenarios and high reduction ratio, can realize multi-turn absolute position encoding of the output end, does not limit the rotation range of the output end, has relatively lower manufacturing cost, and has promotional application value. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 It is a structural schematic diagram of the embodiment 1 of the present application.

[0050] Figure 2 It is a structural schematic diagram of the embodiment 2 of the present application. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0052] Embodiment 1

[0053] An intelligent driving unit, characterized by comprising a motor 1, a reducer 2, a motor control board 3, a plurality of pairs of magnetic rings 4 and a magnetic ring encoder 5.

[0054] The motor 1 is used to output a torque to drive the reducer 2 to rotate, and a magnet is arranged on the top end of the motor shaft close to the motor control board 3.

[0055] The reducer 2 is used to convert the high-speed rotating torque output by the motor 1 into a low-speed rotating torque according to a reduction ratio and to increase the torque.

[0056] The motor control board 3 comprises a magnetic encoding chip 31, a control chip 32 and a motor driving circuit 33. The magnetic encoding chip 31 is arranged above the magnet of the motor shaft of the motor 1 and is used to magnetically encode the real-time stroke and position signal of the magnet on the motor shaft of the motor 1 when the magnet rotates with the motor shaft. The control chip 32 is used to solve the data signal sent by the magnetic encoding chip 31 and the magnetic ring encoder 5 to obtain the rotating stroke and real-time position of the output end of the reducer 2. The motor driving circuit 33 is used to drive the motor 1 to complete torque control, rotating position control, speed control and other control instructions in cooperation with the control chip 32.

[0057] The multiple pairs of pole magnetic rings 4 are fixed on the output end of the speed reducer 2 and rotate coaxially with the output end of the speed reducer 2, and the rotation of the output end of the speed reducer 2 drives the rotation of the multiple pairs of pole magnetic rings 4, and the rotation of the multiple pairs of pole magnetic rings 4 changes the direction and strength of the magnetic field, and the magnetic ring encoder 5 is provided with a magnetic ring encoding chip for monitoring the magnetic signal generated by the change of the magnetic field to perform position encoding; the magnetic ring encoder 5 is connected with the motor control board 3 through signal wires in communication, and is used for sending the encoding data of the magnetic ring encoder 5 to the control chip 32 on the motor control board 3 for calculation.

[0058] The control chip 32 is of the model STM32F103R8T6.

[0059] The magnetic encoding chip 31 is of the model AS5047.

[0060] The magnetic ring encoding chip of the magnetic ring encoder 5 is of the model MT6818 or MT6828.

[0061] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art in the technical range disclosed by the present application, according to the technical scheme and the inventive concept of the present application, equivalent replacement or change, should be covered in the protection scope of the present application.

Claims

1. A method for calculating the absolute position of the output terminal of an intelligent drive unit, characterized in that: Includes motor, reducer, motor control board, multi-pole magnetic ring, and magnetic ring encoder; The motor is used to output torque to drive the reducer to rotate, and a magnet is provided on the top of the motor shaft on the side of the motor near the motor control board. The speed reducer is used to convert the high-speed torque output by the motor into low-speed torque according to the reduction ratio and increase the torque. The motor control board includes a magnetic encoder chip, a control chip, and a motor drive circuit. The magnetic encoder chip is located above the magnet on the motor shaft and is used to magnetically encode the real-time travel and position signals of the magnet on the motor shaft as it rotates with the motor shaft. The control chip is used to decode the data signals sent by the magnetic encoder chip and the magnetic ring encoder to obtain the rotational travel and real-time position of the reducer output. The motor drive circuit is used to cooperate with the control chip to drive the motor to complete torque control, rotational position control, and speed control commands. The multiple pairs of magnetic rings are fixed to the output end of the reducer and rotate coaxially with the output end. When the output end of the reducer rotates, it drives the multiple pairs of magnetic rings to rotate. When the multiple pairs of magnetic rings rotate, they change the direction and intensity of the magnetic field. The magnetic ring encoder is equipped with a magnetic ring encoding chip, which is used to monitor the magnetic signal generated by the change in magnetic field and encode the position. The magnetic ring encoder is connected to the motor control board through a signal wire, which is used to send the encoded data of the magnetic ring encoder to the control chip on the motor control board for processing. The above-mentioned method for calculating the absolute position of the output terminal of the intelligent drive unit includes the following steps: Step (1): First, calculate the periodic relationship between the data of the reducer output, the magnetic encoder, and the magnetic ring encoder. The corresponding formula is as follows: Let the reduction ratio be K:

1. The change in angle at the output end of the reducer corresponding to one revolution of the motor shaft is α, that is, α=360 / K, which is Equation 1; Let the number of magnetic ring pole pairs used in the magnetic ring encoder be J, and the output angle change value β corresponding to one revolution of the electrical angle of the encoding chip is β=360 / J, which is Equation 2; Assume that the data of the motor encoder and the magnetic ring encoder coincide once after the output changes by at least γ degrees, that is, α*M=β*L=γ, where M and L are positive integers and their common divisor is only 1, and γ takes the minimum value that satisfies the equation, which is Equation 3. Step (2): In the scenario with rotation limit, when it is necessary to implement absolute position encoding for the position value of the reducer output shaft, select J and K values ​​so that γ satisfies γ≥θ, where θ is the maximum mechanical angle change value at the motor output end; Step (3): When it is necessary to implement the absolute position encoding of a single circle, select the values ​​of J and K so that γ satisfies γ=360. Combining equations 1 to 3 in step (1), we can get the equation: (360 / K) *M=(360 / J)*L=γ=360. After simplification, we can get M / K=L / J=1, where M and L are positive integers and their common divisor is only 1, i.e., K and J are positive integers and their common divisor is only 1. Step (4): When multi-turn absolute position encoding needs to be implemented, select J and K values such that γ satisfies γ = 360 * H, where H is the number of turns to be encoded. Combining equations 1 to 3 in step (1), we can obtain the equation: (360 / K) * M = (360 / J) * L = γ = 360 * H. After simplification, we get M / K = L / J = H, where M and L are positive integers and their greatest common divisor is only 1; thus M = K * H, L = J * H, where M and L are positive integers and their greatest common divisor is only 1. This is Equation Set 1. The values of K and J only need to satisfy Equation Set 1. Step (5): According to the corresponding application scenarios in steps (2) to (4), combined with the period relationship in step (1) respectively, the following initial position calculation formula after power-off restart of the output end of the drive unit can be obtained: Q = N * D1 + d1 = [(N * D1 + d1) / D2] * D2 + d2 N is a positive integer that satisfies the above formula, and N < M, N < L When solving, first calculate the value of N, and then calculate Q; Where D1 is the larger value of α and β (e.g., if α > β, D1 = α; otherwise, D1 = β); D2 is the smaller value of α and β (e.g., if α < β, D2 = α; otherwise, D2 = β); d1 is the angle value read by the encoding unit corresponding to D1; d2 is the angle value read by the encoding unit corresponding to D2; Q is the absolute position angle of the output end of the reducer; [] represents the rounding operation, that is, it represents the largest integer not greater than the value within []; Step (6): Obtain the dynamic position of the output end, read and calculate the position of the magnetic encoding chip or magnetic ring encoding chip and calculate the corresponding position increment of the output end. Among them: the angle change of the output end = the angle change of the magnetic encoder / K, the angle change of the output end = the angle change read by the magnetic ring encoder / J; According to the formula: the dynamic position of the output end = the initial position + the incremental position, calculate the dynamic position of the output end of the motor, and then the absolute position of the output end of the drive unit can be measured.

2. The method for calculating the absolute position of the output terminal of an intelligent drive unit as described in claim 1, characterized in that: The calculation formula and method in step (5) are as follows: Let the output shaft position deduced from the encoder measurement value corresponding to D1 be q1 with an error of δ1, and the output shaft position deduced from the encoder measurement value corresponding to D2 be q2 with an error of δ2. Then the following equation holds: Q = q1 - δ1 = q2 - δ2 Based on the above formula, the following output shaft position calculation formula can be obtained: Q = N * D1 + d1 - δ1 = [(N * D1 + d1 - δ1 + δ2) / D2] * D2 + d2 - δ2 N is a positive integer that satisfies the above formula, and N < M, N < L Equation 1 F = N * D1 + d1 - δ1 + δ2 - [(N * D1 + d1 - δ1 + δ2) / D2] * D2 - d2 N is a positive integer that satisfies the above formula, and N < M, N < L Equation 2 When both δ1 and δ2 can be obtained, they can be directly substituted into Equation 1 to calculate the value of the output end position Q of the reducer; When only the range of values ​​for δ1 and / or δ2 can be obtained, the possible values ​​of δ1 and δ2 can be substituted one by one into Equation 2 above according to the highest accuracy of the two encoders and the possible value of N. Take N and -δ1+δ2 to minimize F, and substitute them into Equation 1 to obtain the value of the position Q of the reducer output shaft containing the error term. To obtain a more accurate Q, calibration can be used to obtain a more accurate range or value of δ1 and δ2.

3. The method for calculating the absolute position of the output terminal of an intelligent drive unit as described in claim 1 or 2, characterized in that: The control chip is an STM32F103R8T6.

4. The method for calculating the absolute position of the output terminal of an intelligent drive unit as described in claim 1 or 2, characterized in that: The magnetic coding chip mentioned is model AS5047.

5. The method for calculating the absolute position of the output terminal of an intelligent drive unit as described in claim 1 or 2, characterized in that... The magnetic ring encoder described herein uses a magnetic ring encoding chip model of MT6818 or MT6828.

6. The method for calculating the absolute position of the output terminal of an intelligent drive unit as described in claim 3, characterized in that: The magnetic ring encoder described herein uses a magnetic ring encoding chip model of MT6818 or MT6828.

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