Servo system and motor control method based on servo system

Abstract

The embodiment of the invention relates to the field of servo control, in particular to a servo system and a motor control method based on the servo system, and the system comprises a position loop control module, a speed loop control module and a motor module. The position loop control module comprises a speed feed-forward compensator, a position instruction compensator and a position proportion adjusting module; the speed feed-forward compensator is used for generating a first speed instruction; the position instruction compensator is used for compensating the position instruction according to a compensation formula to obtain a compensation result; the position proportion adjusting module is used for generating a second speed instruction according to the compensation result and the position error of the feedback position and outputting the speed instruction; the speed loop control module comprises a speed loop controller and a decoupling expansion state observer; the speed ring controller is used for acquiring a speed instruction, generating a first torque, acquiring an observation speed and an observation torque and outputting an electromagnetic torque instruction to drive the servo motor; according to the servo system control equipment, position overshoot can be reduced, the positioning time is shortened, and therefore the working efficiency of the equipment is improved.

Description

Technical Field

[0001] The present invention relates to the field of servo control, and in particular to a servo system and a motor control method based on the servo system. Background Art

[0002] In recent years, permanent magnet synchronous motor position servo systems have been widely used in industrial automation equipment such as die bonders, sorters, and photolithography machines. Most of these devices use a direct drive transmission structure, using a low-speed, high-torque motor to directly drive the load, eliminating transmission mechanisms such as reducers, gears, and screws. They have the advantages of compact structure, high transmission efficiency, fast dynamic response, and high positioning accuracy. In a direct drive system, since there is no transmission or reduction mechanism, the load disturbance torque will directly act on the motor shaft, causing fluctuations in its speed and position, which requires the servo system to have strong anti-interference capabilities. In addition, in order to improve the working efficiency of the equipment, it is also necessary to further reduce position overshoot and shorten positioning time.

[0003] Using an extended state observer to observe the load torque in real time and perform feedforward compensation is a common method to improve anti-interference performance. However, the tracking and anti-interference performance of the traditional state observer are coupled with each other, which increases the complexity of parameter debugging. In addition, the speed loop is designed as a type I system using a state observer design. Although the speed overshoot is effectively suppressed, the speed steady-state following error increases, resulting in increased overshoot during position positioning and longer positioning time, which is not conducive to improving the working rhythm of the equipment. Even excessive overshoot can easily damage the workpiece. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a servo system and a motor control method based on the servo system. The present invention can achieve the decoupling of tracking and anti-interference performance to reduce the difficulty of parameter debugging, while achieving the effect of improving the responsiveness of the position loop, reducing position overshoot, and shortening the positioning time.

[0005] To solve the above technical problems, an embodiment of the present invention provides a servo system, comprising: a position loop control module, a speed loop control module and a motor module connected in sequence;

[0006] The position loop control module includes: a speed feedforward compensator, a position command compensator and a position ratio adjustment module; the speed feedforward compensator is used to generate a first speed command according to the acquired position command; the position command compensator is used to compensate the position command according to a compensation formula; the position ratio adjustment module is used to obtain the feedback position of the servo motor, generate a second speed command according to the compensation result and the position error of the feedback position, and output the speed command; the speed command is the sum of the first speed command and the second speed command;

[0007] The speed loop control module includes: a speed loop controller and a decoupled extended state observer; the speed loop controller is used to obtain the speed command, generate a first torque, and obtain the observed speed and observed torque and output an electromagnetic torque command to drive the servo motor; the decoupled extended state observer is used to obtain the first torque and the feedback speed of the servo motor, and generate the observed speed and the observed torque; wherein the decoupled extended state observer decouples the followability and anti-disturbance of the servo system from each other; the motor module includes at least the servo motor.

[0008] In addition, the compensation formula as mentioned above is: Among them, G c (s) is the position command compensator, ω sc is the speed loop open loop shear frequency, and s is the Laplace operator.

[0009] In addition, the position proportional regulation module as described above includes a position error device, a position proportional regulator and a first speed error device connected in sequence; the position error device is used to obtain the compensation result and the feedback position, determine and output the position error; the position proportional regulator is used to output the product of the position error and the position loop proportional gain as the second speed instruction; the first speed error device is used to output the sum of the second speed instruction and the first speed instruction as the speed instruction.

[0010] In addition, the speed loop controller as described above includes a second speed error device, a speed proportional regulator and an electromagnetic torque compensator connected in sequence; the second speed error device is used to obtain the speed instruction and the observed speed to determine the speed error; the speed proportional regulator is used to output the product of the speed error and the speed loop proportional gain as the first torque; the electromagnetic torque compensator is used to obtain the first torque and the observed torque, and output the sum of the first torque and the observed torque as the electromagnetic torque instruction to drive the servo motor.

[0011] In addition, the servo system as described above also includes: a disturbance torque adder; the disturbance torque adder is used to obtain the load torque, and output the difference / sum between the electromagnetic torque instruction and the load torque as a target torque instruction instead of the electromagnetic torque instruction to the motor module to drive the servo motor.

[0012] In addition, the motor module as described above further includes: a speed integrator connected to the servo motor; the servo motor is used to perform a rotation operation according to the electromagnetic torque instruction; and the speed integrator is used to generate the feedback position according to the feedback speed of the servo motor.

[0013] In addition, the decoupled extended state observer as described above includes: a first proportional regulator, a first integrator, a second integrator, a first feedback gain regulator, a second feedback gain regulator, a first error detector and a second error detector; the first proportional regulator is used to obtain the first torque and adjust it with a preset proportional coefficient and output it to the first integrator of the two integrators for integration to obtain an integration result; the first error detector is used to determine the error value between the integration result and the feedback speed; the first feedback gain regulator is used to adjust the error value with a preset first feedback gain coefficient to obtain a first adjustment value; the second feedback gain regulator is used to adjust the error value with a preset second feedback gain coefficient to obtain a second adjustment value; the second integrator is used to integrate the second adjustment value to obtain a third adjustment value; the second error detector is used to determine the observed torque based on the error between the third adjustment value and the first adjustment value.

[0014] An embodiment of the present invention also provides a motor control method based on a servo system, which is applied to any servo system as described above, and the method includes: obtaining a position command issued by a host computer, and converting the position command into a first speed command; obtaining a feedback position, and compensating the position command using a compensation formula to obtain a compensation result; generating a second speed command based on the compensation result and the position error of the feedback position; summing the first speed command and the second speed command to obtain a speed command; obtaining an observed speed and an observed torque, determining a first torque based on the speed error between the speed command and the observed speed, and summing the first torque and the observed torque to output as an electromagnetic torque command to drive the servo motor to perform a rotation operation.

[0015] Compared with the related art, the embodiment of the present invention adds a position command compensator to the position loop of the servo system, and designs the position loop to have the same closed-loop control bandwidth as the speed loop, thereby improving the responsiveness of the position loop, reducing position overshoot, and shortening the positioning time; and the speed feedforward coefficient is fixed at 100%, which simplifies parameter setting; at the same time, a decoupling extended state observer is set in the speed loop to achieve decoupling of the speed loop's followability and anti-interference performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by the pictures in the corresponding drawings, and these exemplary descriptions do not constitute limitations on the embodiments.

[0017] Figure 1 The structure of the servo system provided by the embodiment of the present invention is shown in FIG. Figure 1 ;

[0018] Figure 2 The structure of the servo system provided by the embodiment of the present invention is shown in FIG. Figure 2 ;

[0019] Figure 3 The structure of the servo system provided by the embodiment of the present invention is shown in FIG. Figure 3 ;

[0020] Figure 4 is a specific flow chart of a motor control method based on a servo system provided by an embodiment of the present invention;

[0021] Figure 5 It is a comparison diagram of the position following error effects of the present invention provided by an embodiment of the present invention and the prior art. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are provided to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0023] Before describing the present solution in detail, the servo system is described first. The servo system may include any combination of three control loops: position loop, speed loop and current loop. Among them, the current loop is nested in the speed loop, and the speed loop is nested in the position loop. The speed loop is the most common servo control loop. It compares the command speed with the feedback speed through a tachometer or encoder, and issues a command to increase or decrease the motor speed accordingly. For applications that require motor control, a position loop is added outside the speed loop in a so-called cascaded position / speed loop. The position loop determines the following error, that is, the deviation between the feedback position and the command position, and issues a speed command to reduce or eliminate the following error. The main goal of the current loop is to control the torque, which affects the speed and thus the position. The current loop is usually nested in the speed loop, making the current the innermost loop, the speed loop in the middle, and the position loop the outermost loop. Since the current loop response bandwidth is much higher than the position loop and the speed loop, it can be considered that the current can be accurately followed, so the current loop is regarded as a through in the embodiment of the present invention.

[0024] An embodiment of the present invention relates to a servo system, such as Figure 1 As shown, the servo system in this embodiment specifically includes: a position loop control module 1, a speed loop control module 2 and a motor module 3 connected in sequence;

[0025] The position loop control module 1 includes: a speed feedforward compensator 10, a position command compensator 11 and a position ratio adjustment module 12;

[0026] The speed feedforward compensator 10 is used to generate a first speed command according to the acquired position command; the position command compensator 11 is used to compensate the position command according to the compensation formula to obtain a compensation result; the position ratio adjustment module 12 is used to obtain the feedback position of the servo motor, generate a second speed command according to the compensation result and the position error of the feedback position, and output the speed command; the speed command is the sum of the first speed command and the second speed command;

[0027] The speed loop control module 2 includes: a speed loop controller 21 and a decoupled extended state observer 22; the speed loop controller 21 is used to obtain a speed command, generate a first torque, and obtain an observed speed and an observed torque and output an electromagnetic torque command to drive the servo motor; the decoupled extended state observer 22 is used to obtain the first torque and the feedback speed of the servo motor, and generate an observed speed and an observed torque; wherein the decoupled extended state observer 22 decouples the followability and anti-interference performance of the servo system from each other; the motor module 3 includes at least a servo motor 31.

[0028] Specifically, the servo system in the present embodiment is mainly used to control a permanent magnet synchronous motor. In the present embodiment, the servo motor 31 is a permanent magnet synchronous motor in practical applications, and this application will not be repeated later. The position loop control module 1 of the servo system is a part of the position loop (not shown in the figure), which mainly plays a role of monitoring and adjustment. The position loop control module 1 obtains a position instruction from the host computer, which is a target position value sent to the servo system, indicating the desired final position or position change. The position instruction can be an absolute position (for example, given a specific position value) or a relative position (for example, given a position change), and this application does not make specific restrictions on this. In the present embodiment, the position instruction is used to instruct the servo motor 31 to rotate to a certain angle or rotate to a certain angle.

[0029] Feedback position and feedback speed refer to feedback information obtained from the servo motor 31. Generally speaking, an encoder, a position sensor or other feedback device is installed in the servo system. The feedback signal of the motor is obtained through the feedback device such as the encoder. The feedback signals obtained by different feedback devices are different (such as: the feedback signal of the position sensor is the feedback position, and the feedback signal of the speed sensor is the feedback speed). The position loop control module 1 can generate a corresponding speed command to adjust the position error according to the received position command and feedback position. The speed command represents the target speed value sent to the servo system, which is used to control the servo motor 31 to operate at the target speed. Therefore, the position loop control module 1 can obtain the position command issued by the host computer and generate a speed command output.

[0030] Accordingly, the position loop control module 1 includes a speed feedforward compensator 10, a position command compensator 11 and a position proportional adjustment module 12. After the position loop control module 1 obtains the position command issued by the host computer (not shown in the figure), the speed feedforward compensator 10 in the position loop control module 1 can generate a first speed command according to the obtained position command. In addition, the position command compensator 11 in the position loop control module 1 is used to compensate the position command according to the compensation formula to obtain a compensation result; the position proportional adjustment module 12 is used to obtain the feedback position of the servo motor 31, generate a second speed command according to the compensation result and the position error of the feedback position, and output the sum of the first speed command and the second speed command as the speed command.

[0031] After the speed loop control module 2 obtains the speed command generated by the position loop control module 1, it also obtains the observed speed, and then generates an output electromagnetic torque command based on the error between the speed command and the observed speed to drive the servo motor 31 to perform a rotation operation. The speed loop control module 2 includes: a speed loop controller 21 and a decoupled extended state observer 22; the speed loop controller 21 obtains the speed command, generates a first torque, and obtains the observed speed and the observed torque and outputs an electromagnetic torque command to drive the servo motor 31; the decoupled extended state observer 22 is used to obtain the first torque and the feedback speed of the servo motor 31, and generate the observed speed and the observed torque; wherein, the decoupled extended state observer 22 can decouple the followability and anti-disturbance of the speed loop of the servo system from each other, simplifying the setting of the control parameters of the servo system.

[0032] In one example, the compensation formula is: Among them, G c (s) is the position command compensator, ω sc is the speed loop open loop shear frequency, and s is the Laplace operator.

[0033] Specifically, the position command compensator is a compensation controller, and its compensation formula can be determined according to the structure of the servo system. Since the position loop bandwidth is usually lower than the speed loop bandwidth, in order to increase the position loop bandwidth and reduce overshoot at the same time, the present embodiment can make the position loop and the speed loop closed-loop transfer functions equal to determine the compensation formula of the position command compensator.

[0034] In an example, Figure 2 As shown, the position ratio adjustment module 12 includes a position error device 121, a position ratio adjustment device 122 and a first speed error device 123 which are connected in sequence;

[0035] On this basis, the position ratio adjustment module 12 is used to obtain the feedback position of the servo motor 31, and generate a second speed instruction according to the compensation result and the position error of the feedback position, including:

[0036] The position error detector 121 is used to obtain the compensation result and feedback position, determine and output the position error; the position proportional regulator 122 is used to output the product of the position error and the position loop proportional gain as the second speed instruction; the first speed error detector 123 is used to output the sum of the second speed instruction and the first speed instruction as the speed instruction.

[0037] Specifically, the compensation result is obtained by calculating the compensation formula and the position command. The position error device 121 is used to obtain the compensation result and the feedback position of the servo motor 31 (motor module 3), and the position error between the position compensation result and the feedback position can be determined; the position proportional regulator 122 can determine the second speed command according to the position error and the position loop proportional gain, wherein the position loop proportional gain K pp is a known parameter of the position proportional regulator 122. The second speed command can be determined by multiplying the position error by the position loop proportional gain. After the first speed error detector 123 obtains the first speed command and the second speed command, it outputs the sum of the second speed command and the first speed command as the speed command.

[0038] Accordingly, in one example, Figure 2 As shown, the speed loop controller 21 includes a second speed error device 211, a speed ratio regulator 212 and an electromagnetic torque compensator 213 connected in sequence;

[0039] On this basis, the speed loop controller is used to obtain a speed command, generate a first torque, obtain an observed speed and an observed torque, and output an electromagnetic torque command to drive the servo motor 31, including:

[0040] The second speed error device 211 is used to obtain the speed command and the observed speed to determine the speed error; the speed proportional regulator 212 is used to output the product of the speed error and the speed loop proportional gain as the first torque; the electromagnetic torque compensator 213 is used to obtain the first torque and the observed torque, and output the sum of the first torque and the observed torque as the electromagnetic torque command to drive the servo motor 31.

[0041] Specifically, the speed loop in this embodiment is a type I system. After the speed loop controller 21 obtains the speed command output by the position loop control module 1, the second speed error device 211 in the speed loop controller 21 compares the obtained speed command with the observed speed output by the decoupled extended state observer 22, and can determine the speed error between the speed command and the observed speed. The speed proportional regulator 212 can determine the first torque according to the product of the speed error and the speed loop proportional gain, where the speed loop proportional gain K vis a known parameter of the speed ratio regulator 212. The decoupled extended state observer 22 generates the observed speed and observed torque by acquiring the feedback speed and the first torque. After the electromagnetic torque compensator 213 acquires the first torque and the observed torque, it outputs the sum of the two as the electromagnetic torque command to drive the servo motor 31 to perform the rotation operation.

[0042] In another example, Figure 2 As shown, the servo system of this embodiment also includes: a disturbance torque adder 4; the disturbance torque adder is used to obtain the load torque, and output the difference / sum between the electromagnetic torque command and the load torque as the target torque command instead of the electromagnetic torque command to the motor module to drive the servo motor 31.

[0043] Specifically, load torque disturbance will affect the control performance of the permanent magnet synchronous motor (servo motor 31). Since the load torque is measured or observed, the target torque instruction resulting from the calculation of the load torque and the electromagnetic torque instruction is output to the motor module to drive the servo motor 31, the impact of external disturbance on the servo motor 31 can be reduced.

[0044] In an example, Figure 2 As shown, the motor module 3 further includes: a speed integrator 32 connected to the servo motor 3131;

[0045] The servo motor 31 is used to perform a rotation operation according to an electromagnetic torque instruction; the speed integrator 32 is used to generate a feedback position according to a feedback speed of the servo motor 31 .

[0046] Specifically, during the rotation operation of the servo motor 31 , a feedback device in the servo motor 31 acquires a feedback speed, and the feedback speed is output as a feedback position through the speed integrator 32 .

[0047] In another example, Figure 3 As shown, the decoupled extended state observer 22 includes: a first proportional regulator 221, a first integrator 222, a second integrator 223, a first feedback gain regulator 224, a second feedback gain regulator 225, a first error detector 226 and a second error detector 227;

[0048] The first proportional regulator 221 is used to obtain the first torque and to adjust the first torque to the preset proportional coefficient 1 / J s is adjusted and output to the first integrator 222 for integration to obtain an integration result; wherein, J sis the system inertia, s is the Laplace operator; the first error detector 226 is used to determine the error value between the integration result and the feedback speed; the first feedback gain regulator 224 is used to adjust the error value with a preset first feedback gain coefficient l1 to obtain a first adjustment value; the second feedback gain regulator 225 is used to adjust the error value with a preset second feedback gain coefficient l2 to obtain a second adjustment value; the second integrator 223 is used to integrate the second adjustment value to obtain a third adjustment value; the second error detector 227 is used to determine the observed torque according to the error between the third adjustment value and the first adjustment value

[0049] In order to facilitate a better understanding of this solution, the principle of the solution of this embodiment is now specifically analyzed.

[0050] like Figure 3 As shown, the working principle of the decoupled extended state observer 22 is as follows:

[0051]

[0052] It can be concluded that the observed speed of the servo system state variables is Observation torque The feedback speed ω output by the servo system m , electromagnetic torque command T e The relational expression is as follows:

[0053]

[0054] in, is the speed command; ω m is the feedback speed; K v is the speed loop proportional gain; T e is the electromagnetic torque command; T l is the load torque; J s is the system inertia; l1 is the first feedback gain coefficient of the state observer feedback matrix; l2 is the second feedback gain coefficient of the state observer feedback matrix; is the observed speed; is the observed torque; s is the Laplace operator.

[0055] Since the performance of the servo system control system is usually evaluated by its followability and anti-interference performance, we first analyze the following performance of the above system to the speed command. Let T l =0, then T e =J s sω m , substituting into formula (2) we can get: The closed-loop transfer function of the speed loop can be obtained as:

[0056]

[0057] Next, we analyze the system's anti-load disturbance performance. Then T e =J s sω m +T l , substituting into formula (6), the closed-loop transfer function of the system load torque-feedback speed can be obtained as:

[0058]

[0059] Among them, ω eso is the bandwidth of the observer.

[0060] According to formula (4), the anti-disturbance performance of the servo system is only determined by the observer bandwidth ω eso Decision. And with ω eso As the speed loop increases, the system's ability to suppress load disturbances increases. According to formula (3), the system's following performance is only determined by the speed loop open-loop shear frequency ω. sc It is determined that the decoupled extended state observer of this embodiment can achieve the decoupling of followability and anti-disturbance, and simplify the setting of the control parameters of the servo system.

[0061] In the prior art, the closed-loop transfer function of the undecoupled system load torque-output speed is usually:

[0062]

[0063] According to the above formula, it can be seen that the anti-disturbance performance of the system is related to the observer bandwidth ω eso and speed loop open loop shear frequency ω sc It is related that the tracking performance and the anti-disturbance performance are coupled with each other when the conventional extended state observer is used in the prior art.

[0064] Furthermore, if Figure 3 The position loop closed-loop transfer function of the servo system shown is as follows:

[0065]

[0066] Usually, the position loop bandwidth in a servo system is lower than the speed loop bandwidth. In order to increase the position loop bandwidth and reduce overshoot, the closed-loop transfer functions of the position loop and the speed loop can be made equal, that is, G p (s) = G ω (s), the position command compensator can be obtained:

[0067]

[0068] It can be seen from formula (6) that after adding the compensation link, the position loop becomes a type I system, which has the advantage of small overshoot, and the position loop bandwidth is equal to the speed loop bandwidth, which improves the responsiveness of the position loop. The speed feedforward coefficient is fixed at 100%, which also simplifies the setting of the speed feedforward coefficient.

[0069] Compared with the related art, the embodiment of the present application adds a position command compensator to the position loop of the servo system, and designs the position loop to have the same closed-loop control bandwidth as the speed loop, thereby improving the responsiveness of the position loop, reducing position overshoot, and shortening the positioning time; and the speed feedforward coefficient is fixed at 100%, which simplifies parameter setting; at the same time, setting a decoupling extended state observer in the speed loop can achieve decoupling of the speed loop's followability and anti-interference performance.

[0070] On the basis of the above servo system, another embodiment of the present invention relates to a motor control method based on a servo system. The control method of the present invention can be performed based on the servo system of the above embodiment. On this basis, the specific process of the motor control method based on the servo system provided in this embodiment is as follows: Figure 4 As shown, the specific steps include:

[0071] Step 101: Obtain a position command issued by a host computer, and convert the position command into a first speed command;

[0072] Step 102: Obtain the feedback position, and use the compensation formula to compensate the position command to obtain a compensation result; generate a second speed command according to the compensation result and the position error of the feedback position; and obtain a speed command by summing the first speed command and the second speed command;

[0073] Step 103: Obtain the observed speed and the observed torque, determine the first torque according to the speed error between the speed command and the observed speed, sum the first torque and the observed torque and output them as the electromagnetic torque command to drive the servo motor to perform a rotation operation.

[0074] Specifically, the position loop control module of the servo system obtains the position instruction from the host computer, and the position instruction is the target position value sent to the servo system, indicating the required final position or position change. The position instruction can be an absolute position (for example, given a specific position value) or a relative position (for example, given a position change), and the present application does not make specific restrictions on this. In this embodiment, the position instruction is used to instruct the servo motor to rotate to a certain angle or rotate to a certain angle. Feedback position and feedback speed refer to feedback information obtained from the servo motor. Generally speaking, an encoder, a position sensor or other feedback device is installed in the servo system, and the feedback signal of the motor is obtained by the feedback device such as the encoder. The feedback signals obtained by different action feedback devices are different (such as: the feedback signal of the position sensor is the feedback position, and the feedback signal of the speed sensor is the feedback speed). The position loop control module can generate a corresponding speed instruction to adjust the position error according to the received position instruction and feedback position. The speed instruction represents the target speed value sent to the servo system, which is used to control the servo motor to operate according to the target speed. Therefore, the position loop control module can obtain the position instruction issued by the host computer and generate a speed instruction output. Correspondingly, the position loop control module includes a speed feedforward compensator, a position command compensator and a position proportional adjustment module. After the position loop control module obtains the position command issued by the host computer (not shown in the figure), the speed feedforward compensator in the position loop control module can generate a first speed command according to the obtained position command. In addition, the position command compensator in the position loop control module is used to compensate the position command according to the compensation formula to obtain the compensation result; the position proportional adjustment module is used to obtain the feedback position of the servo motor, generate a second speed command according to the compensation result and the position error of the feedback position, and output the sum of the first speed command and the second speed command as the speed command. After the speed loop control module of the servo system obtains the speed command generated by the position loop control module, it will also obtain the observed speed, and then generate the output electromagnetic torque command according to the error between the speed command and the observed speed to drive the servo motor to perform rotation operation. The speed loop control module includes: a speed loop controller and a decoupled extended state observer; the speed loop controller obtains a speed command, generates a first torque, and obtains an observed speed and an observed torque and outputs an electromagnetic torque command to drive a servo motor; the decoupled extended state observer obtains the first torque and the feedback speed of the servo motor, and generates an observed speed and an observed torque; wherein the decoupled extended state observer can decouple the followability and anti-interference ability of the speed loop of the servo system from each other, thereby simplifying the setting of the control parameters of the servo system.

[0075] In one example, the compensation formula is: Among them, G c (s) is the position command compensator, ω sc is the speed loop open loop shear frequency, and s is the Laplace operator.

[0076] Specifically, the position command compensator is a compensation controller, and its compensation formula can be determined according to the structure of the servo system. Since the position loop bandwidth is usually lower than the speed loop bandwidth, in order to increase the position loop bandwidth and reduce overshoot at the same time, the present embodiment can make the position loop and the speed loop closed-loop transfer functions equal to determine the compensation formula of the position command compensator.

[0077] It should be noted that the steps in this embodiment are described in sequence according to the linear characteristics of the servo system and the order of the modules in the servo system, which does not mean a strict execution order. In fact, the above steps will constitute a closed execution system when executed. In practical applications, the execution order can be reasonably adjusted according to the specific execution situation.

[0078] It is not difficult to find that this embodiment is a method embodiment corresponding to the above embodiment, and the relevant technical details mentioned in the above embodiment are still valid in this embodiment. In order to reduce repetition, they are not repeated here. Accordingly, the relevant technical details mentioned in this embodiment can also be applied in the above embodiment.

[0079] In order to better demonstrate the effect of reducing position following error brought by this solution, Figure 5 As shown, this embodiment also provides a set of verification comparisons.

[0080] The position command adopts the 7-segment S-curve commonly used in industry, with a position movement of 0.5 revolutions (the motor encoder resolution is 23 bits, that is, the displacement of the motor rotating 0.5 revolutions is 4194304 pulses), a profile speed of 1000r / min, an acceleration setting of 100ms from 0r / min to 1000r / min, and a speed feedforward coefficient of 100%. The position positioning response of the three control structures of traditional P-PI control, P-DESO (decoupled extended state observer) control without compensation, and P-DESO control + compensation method (P-CMP-DESO) proposed by the present invention is compared. Figure 5 shown.

[0081] from Figure 5 It can be seen that with the traditional P-PI control structure, the position overshoot is 7696 pulses, and the position feedback rebounds, and the positioning time is very long; with the P-DESO control structure, the positioning time is shortened, but the overshoot is significantly increased to 50696 pulses; with the P-CMP-DESO control structure, the overshoot is the smallest at only 30 pulses, and the positioning time is also the shortest. The experimental results show that the method proposed by the present invention has the advantages of small position overshoot and short positioning time.

[0082] The step division of the above methods is only for the purpose of clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0083] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0084] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0085] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A servo system, characterized in that: include: A position loop control module, a speed loop control module and a motor module connected in sequence; The position loop control module includes: a speed feedforward compensator, a position command compensator and a position ratio adjustment module; the speed feedforward compensator is used to generate a first speed command according to the acquired position command; the position command compensator is used to compensate the position command according to a compensation formula to obtain a compensation result; the position ratio adjustment module is used to obtain the feedback position of the servo motor, generate a second speed command according to the compensation result and the position error of the feedback position, and output the speed command; the speed command is the sum of the first speed command and the second speed command; The speed loop control module includes: a speed loop controller and a decoupled extended state observer; the speed loop controller is used to obtain the speed command, generate the first torque, and obtain the observed speed and the observed torque and output the electromagnetic torque command to drive the servo motor; the decoupled extended state observer is used to obtain the first torque and the feedback speed of the servo motor, and generate the observed speed and the observed torque; wherein the decoupled extended state observer decouples the followability and anti-disturbance of the servo system from each other; The motor module at least includes the servo motor.

2. The servo system according to claim 1, characterized in that: The compensation formula is: Among them, G c (s) is the position command compensator, ω sc is the speed loop open loop shear frequency, and s is the Laplace operator.

3. The servo system according to claim 1, characterized in that: The position ratio adjustment module includes a position error device, a position ratio adjustment device and a first speed error device which are connected in sequence; The position error device is used to obtain the compensation result and the feedback position, determine and output the position error; The position proportional regulator is used to output the product of the position error and the position loop proportional gain as the second speed instruction; The first speed error device is used to output the sum of the second speed instruction and the first speed instruction as the speed instruction.

4. The servo system according to claim 3, characterized in that: The speed loop controller comprises a second speed error device, a speed ratio regulator and an electromagnetic torque compensator which are connected in sequence; The second speed error device is used to obtain the speed instruction and the observed speed to determine the speed error; The speed proportional regulator is used to output the product of the speed error and the speed loop proportional gain as the first torque; The electromagnetic torque compensator is used to obtain the first torque and the observed torque, and output the sum of the first torque and the observed torque as the electromagnetic torque command to drive the servo motor.

5. The servo system according to claim 1, characterized in that: The system also includes: a disturbance torque adder; the disturbance torque adder is used to obtain the load torque, and output the difference / sum between the electromagnetic torque instruction and the load torque as a target torque instruction instead of the electromagnetic torque instruction to the motor module to drive the servo motor.

6. The servo system according to claim 4 or 5, characterized in that: The motor module further comprises: a speed integrator connected to the servo motor; The servo motor is used to perform a rotation operation according to the electromagnetic torque instruction; the speed integrator is used to generate the feedback position according to the feedback speed of the servo motor.

7. The servo system according to claim 6, characterized in that: The decoupled extended state observer includes: a first proportional regulator, a first integrator, a second integrator, a first feedback gain regulator, a second feedback gain regulator, a first error detector and a second error detector; The first proportional regulator is used to obtain the first torque and adjust it with a preset proportional coefficient and output it to the first integrator of the two integrators for integration to obtain an integration result; The first error device is used to determine the error value between the integration result and the feedback speed; The first feedback gain regulator is used to adjust the error value by a preset first feedback gain coefficient to obtain a first adjustment value; The second feedback gain regulator is used to adjust the error value with a preset second feedback gain coefficient to obtain a second adjustment value; the second integrator is used to integrate the second adjustment value to obtain a third adjustment value; The second error device is used to determine the observed torque according to an error between the third adjustment value and the first adjustment value.

8. A motor control method based on a servo system, characterized in that: Applied to the servo system according to any one of claims 1 to 7, the method comprises: Obtaining a position command issued by a host computer, and converting the position command into a first speed command; Acquire the feedback position, and use a compensation formula to compensate the position command to obtain a compensation result; generate a second speed command according to the compensation result and a position error of the feedback position; The speed command is obtained by summing the first speed command and the second speed command; The observed speed and the observed torque are obtained, a first torque is determined according to a speed error between the speed command and the observed speed, and the first torque is summed with the observed torque and output as an electromagnetic torque command to drive the servo motor to perform a rotation operation.

9. The method according to claim 8, characterized in that The compensation formula is: Among them, G c (s) is the position command compensator, ω sc is the speed loop open loop shear frequency, and s is the Laplace operator.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the servo system-based motor control method according to any one of claims 8 to 9 is implemented.

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