A control method based on multiple motor speed-position synchronization

Abstract

The application belongs to the technical field of automatic control, and particularly relates to a control method based on speed-position synchronization of multiple motors. The deviation coupling synchronization control structure can effectively eliminate position errors while ensuring speed coupling, and realizes speed-position double synchronization. The method comprises the following steps: an improved deviation coupling multi-motor control structure is adopted; a relative speed signal of each motor is added in a speed feedback signal according to a damping coefficient relationship between each motor system; and a speed compensation signal is dynamically distributed among the motors according to the working state of each motor, so as to realize synchronization control of the multiple motors.

Description

Technical Field

[0001] This invention belongs to the field of automatic control technology, and in particular relates to a control method based on the speed-position synchronization of multiple motors. Background Technology

[0002] Research on multi-motor synchronous control involves disciplines such as electrical engineering, mechanical engineering, control theory, computer technology, and information science. It is characterized by its broad scope and strong interdisciplinary nature, and has wide applications in many practical engineering fields, such as papermaking, steel rolling, textiles, and CNC lathes. The purpose of developing synchronous control is to enable the controlled object to achieve high-precision, high-stability synchronous or proportional control. Therefore, research on multi-motor synchronous control methods is of great significance for both theoretical exploration and practical engineering applications.

[0003] Currently, most research in the field of multi-motor control focuses on the importance of speed synchronization among multiple motors. However, with social development and industrial needs, the importance of position synchronization among multiple motors is also becoming increasingly prominent. For example, in the automatic hoisting of 100-meter steel rails and multi-axis coordinated operation, the positions of each motor need to be highly synchronized. In these operating conditions, the synchronization of motor positions is more important than speed synchronization. Therefore, to achieve multi-motor speed-position synchronization control, this invention is an improved design based on the traditional deviation-coupled multi-motor synchronization control structure. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a control method based on the speed-position synchronization of multiple motors. It not only enables synchronized control of the speed and position of multiple motors but also allows for flexible adjustment of the proportional parameter Q to adapt to various operating conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution, including an improved deviation-coupled multi-motor control structure; adding the relative speed signal of each motor to the speed feedback signal according to the damping coefficient relationship between each motor system; and dynamically distributing speed compensation signals among each motor according to the working state of each motor, thereby realizing synchronous control of multiple motors.

[0006] Furthermore, the improved deviation-coupled multi-motor control structure includes: adding a position compensation module to the compensation stage of the classic deviation-coupled control structure, comprehensively considering the speed and position errors caused by motor parameters, load fluctuations, and disturbances (such as factors), and simultaneously correcting the speed compensation value and the position compensation value; and introducing a feedback proportional parameter Q to be applicable to various working conditions.

[0007] Furthermore, the classical deviation coupling control structure (such as...) Figure 1 In ), the structure of the motor speed compensator (such as Figure 2The method involves subtracting the actual speed of the controlled motor from the actual speeds of all other motors, summing the results, and then multiplying the sum by an appropriate coefficient K. ij (This coefficient is usually taken as the ratio of the moment of inertia J of each motor, i.e., K) ij =J i / J j The summation of the actual speed difference between any two of the N motors is used as the control input compensation for the controlled motor.

[0008] Furthermore, due to the addition of a position compensation module, each motor in the control structure feeds back speed and position signals, and each motor's speed compensator and position compensator receive the response signals and output corresponding speed compensation signals and position compensation signals. The two signals are added together after being fed back by the proportional parameter (1-Q) and Q gain, respectively, and used as the total compensation signal input to the follower controller, thereby realizing multi-motor speed-position synchronous control.

[0009] Furthermore, the control structure can simultaneously observe signal fluctuations in speed and position and couple them for control to achieve dual synchronization of speed and position. The proportional gain in the position compensator is Q (in order to ensure that the speed and position outputs stably follow the target value, the total feedback value must be kept within the normal range). The gain of the speed compensator is (1-Q).

[0010] Compared with the prior art, the present invention has the following advantages.

[0011] The deviation coupling synchronization control structure proposed in this invention can effectively eliminate position errors while ensuring speed coupling, thus achieving speed-position dual synchronization.

[0012] This invention introduces a feedback ratio Q, which allows it to be applied to any operating condition. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.

[0014] Figure 1 This is a diagram of a classic deviation coupling control structure.

[0015] Figure 2 This is a structural diagram of a classic motor speed compensator.

[0016] Figure 3 This is a diagram of the synchronization control structure of the present invention.

[0017] Figure 4 This is a structural diagram of the motor position compensator of the present invention.

[0018] Figure 5 This is a structural diagram of the motor speed compensator of the present invention.

[0019] Figure 6 This is a comparison chart showing the variation of the maximum position error of the four motors in two different multi-motor control structures.

[0020] Figure 7 The figures show the speed variation curves of the four motors in this invention. Detailed Implementation

[0021] like Figure 1-7 As shown in the accompanying drawings, in order to make the objectives, technical solutions and advantages of the present invention clearer, the implementation measures of the present invention will be further described below in conjunction with the accompanying drawings.

[0022] The workflow of a multi-motor control system can be broadly divided into two parts. The first part is the multi-motor start-up phase:

[0023] like Figure 3 As shown, the target speed of the multi-motor system is first set to V. ref Then V ref After passing through adder 2, the signal is transmitted to each follower controller. Since the motors have not yet started, the total feedback value output by adder 1 and the motor speed v are both 0. Therefore, the signal output by adder 2 is still V. ref The controller receives signals from adder 2 and sends a start signal to the motor. After the motor starts, its actual speed V is fed back to adder 1, forming a closed-loop control system. Each motor outputs a speed signal V. After integrating the speed signal over time, a position signal S for that motor is output. The position signal S and the speed signal V are then fed back to the position compensator and speed compensator of each motor, respectively. Figure 4 As shown, taking the first motor as an example, after the position signals S and speed signals V of N motors are output, they are fed back to position compensator 1 and speed compensator 1. The position signal of the first motor is then subtracted from the signals of the other motors and added together to obtain the total position compensation signal. After being amplified by the feedback proportional parameter Q, the output is the position compensation signal for the first motor. The speed compensator calculates compensation on the same principle as the position compensator, with one difference: the position feedback proportional parameter is Q, and the speed feedback proportional parameter is (1-Q), as shown below. Figure 5 As shown, the signals output from the position compensator and the speed compensator are added together as the total compensation signal input to adder 2. This constitutes a multi-motor speed-position synchronous control structure.

[0024] The second part is the disturbance rejection stage during multi-motor operation:

[0025] After the motor starts, each motor operates at V... refThe motor operates at its normal speed. In practical applications, one of the motors will inevitably be subjected to external disturbances of varying force, causing speed fluctuations and resulting in speed and position differences. For example, if motor 2 is disturbed, during the simulation, T can be... L2 The disturbance torque is input to adder 4 to simulate the disturbance situation of the motor. At this time, T L2 The output signal is subtracted from the output signal of the follower controller 2, and the resulting signal is sent to motor 2. However, while all other motors are operating normally, motor 2, upon receiving the abnormal signal, experiences a speed reduction trend. Consequently, the position signal of motor 2 also shows a corresponding decrease and is transmitted to the position compensators of each motor. The compensators for each motor are largely similar, differing only in their compensation calculation methods. For example... Figure 4 As shown, Figure 4 For the position compensator of the first motor, the calculation method is to subtract the position signals of the other motors from the position signal of the first motor and then sum them up before outputting the result. Similarly, the position compensator of motor 2 is calculated by subtracting the position signals of the other motors from its position signal S2 and then summing the results. The same principle applies to the speed compensator and the position compensator. It can be seen that the speed and position signals output by each motor have the greatest impact on its own compensator. Therefore, when the speed output signal V2 and the position output signal S2 of motor 2 show a downward trend, the output signals of both speed compensator 2 and position compensator 2 will decrease. Since the output signal of adder 2 is V... ref Subtracting V2 and the total compensation value, as V2 decreases, the total compensation value decreases, so the output signal of adder 2 quickly increases and re-stabilizes to V. ref .

[0026] Because the deviation-coupled multi-motor control structure has strong coupling characteristics, when V2 decreases, other motors will also experience a slight speed reduction, but less than V2. Similarly, the position signal fluctuations are similar to the speed fluctuations. However, due to the presence of a position compensator in this invention, the positions of the multiple motors tend to synchronize under the strong coupling of their positions. Since V2 fluctuates significantly, under the effect of multi-motor position coupling, V2 returns to V2. ref The speed must be greater than the return speed of other motors to compensate for V. 2min The position difference of motor 2. Therefore, the multi-motor control structure of this invention can ensure both speed synchronization and position synchronization after being disturbed.

[0027] Regarding the feedback ratio parameter Q:

[0028] The Q value is designed to adjust the compensation ratio between speed and position; therefore, an appropriate Q value can be selected according to the actual operating conditions.

[0029] To verify the feasibility of this invention, the following simulations were performed using MATLAB / Simulink:

[0030] Four permanent magnet synchronous motors with identical parameters were used as the controlled objects in a simulation study, and the results were compared with those of a classic deviation-coupled control structure. Q = 0.7, simulation time t = 10s, and the load on motor 2 increased by 10 (N*m) at 2s. A PI controller was used to follow and control each motor.

[0031] Figure 6 The graph shows the position error variation under two control structures. Figure 6 It can be seen that under the classical deviation coupling synchronous control, after a sudden load change in motor 2 (2s), the position error between the motors reaches 1.9 rad within 0.3s and remains at this position difference without any convergence trend. This indicates that the classical deviation coupling synchronous control cannot eliminate the position error between multiple motors after a sudden load change in one motor. In contrast, the improved deviation coupling synchronous control reaches a maximum position error of 3.5 rad after a sudden load change, but the error between the motors becomes zero after 4s. This demonstrates that under the multi-motor control structure of this invention, when the motors are subjected to load fluctuations, the position error between the motors can be quickly eliminated, exhibiting better dynamic position synchronization control performance. Figure 7 The speed variation curves of the four motors in this invention are shown below. Figure 7 It can be seen that under the multi-motor control structure of the present invention, when motor 2 is disturbed by the load, the speed decreases, but it can quickly return to the target speed, thus ensuring the speed synchronization between multiple motors.

[0032] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A control method based on speed-position synchronization of multiple motors, characterized in that: This includes adopting a deviation-coupled multi-motor control structure; adding the relative speed signal of each motor to the speed feedback signal according to the damping coefficient relationship between each motor system; and dynamically distributing speed compensation signals among each motor according to the working state of each motor, thereby achieving synchronous control of multiple motors. The aforementioned deviation-coupled multi-motor control structure includes: adding a position compensation module to the compensation stage of the classic deviation-coupled control structure; comprehensively considering speed and position errors caused by motor parameters, load fluctuations, and disturbances; and simultaneously correcting the speed compensation value and the position compensation value; and introducing a feedback proportional parameter to be applicable to various operating conditions. Q ; In the aforementioned classic deviation coupling control structure, the motor speed compensator structure involves subtracting the actual speed of the controlled motor from the actual speeds of each of the other motors, and then multiplying each difference by a coefficient. K ij Then sum them up to get the speed compensation value; K ij =J i / J j , J i This represents the moment of inertia of the controlled motor. J j This represents the moment of inertia of each of the other motors; Because a position compensation module has been added, each motor in the control structure feeds back speed and position signals separately. Each motor's speed compensator and position compensator receive the response signals and output corresponding speed and position compensation signals. These two compensation signals are then fed back through a proportional parameter (1- Q )and Q The gains are summed and used as the total compensation signal input to the follower controller, thereby achieving multi-motor speed-position synchronous control.

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