Point-to-point position servo control system based on disturbance observation and compensation

Abstract

The invention relates to the technical field of motor control, and discloses a point-to-point position servo control system based on disturbance observation and compensation. An encoder position sensor detects the position of a motor rotor of a permanent magnet synchronous motor to obtain a position signal; the position signal and the quadrature-axis current feedback value serve as input of the disturbance observation and compensation module to obtain an acceleration observation value and a disturbance current compensation value; after a position error signal is obtained by subtracting a position signal from a given position instruction, an initial given value of q-axis current is output through a position loop PD controller, and after an acceleration observation value is subtracted from the initial given value of the q-axis current, a disturbance current compensation value is superposed to obtain axis current after disturbance compensation. And the direct-axis current given value and the shaft current generate a control signal of the synchronous motor through the current loop control module. According to the invention, through real-time observation and offset of disturbance, the influence of disturbance on position errors is blocked, and the control precision is improved. By compensating various disturbances, the anti-interference capability is improved, and the method adapts to complex working conditions.

Description

Technical Field

[0001] This invention belongs to the field of motor control technology, specifically relating to a point-to-point position servo control system based on disturbance observation and compensation. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in computer numerical control (CNC) machine tools, elevator control, robotics, textile machinery, and other fields due to their advantages such as high power factor, high efficiency, fast dynamic response, and high reliability. With the continuous expansion of servo system applications, many scenarios require high acceleration and high positioning accuracy at critical points in integrated circuit manufacturing, particularly in chip packaging equipment. The motion of the packaging equipment can be considered as point-to-point motion with high response requirements, where the speed error only needs to be less than a specific value. Some CNC machine tools (such as boring and milling machines) require high-precision point-to-point positioning control for workpieces and tools. Warp knitting machines in textile machinery and industrial robots in production lines require high response speed and positioning accuracy. These applications share common characteristics: high dynamic performance of servo system position response, small position following error, strong anti-interference capability, and low-speed control requirements, which align with the point-to-point motion characteristics of servo systems.

[0003] Point-to-point motion only requires the final position, regardless of the intermediate process or trajectory. The focus is on the dynamic performance of the system's position response, with less emphasis on speed regulation performance. In this case, the speed closed loop not only has no significant effect but also, as an inertial series element in the control structure, reduces the dynamic response performance of the system's position regulation. Furthermore, the presence of the speed closed loop inevitably increases the order of the entire control system, making it prone to oscillation and increasing the difficulty of system debugging. However, in a dual-loop servo control system with both position and current loops, the lack of a speed closed loop inevitably results in larger steady-state errors and poorer anti-interference performance compared to traditional three-loop servo systems, thus limiting the application of dual-loop position servo systems. Traditional servo system motor position control uses simple dual-loop PI control without a disturbance compensation system, making it unable to actively respond to disturbances. This leads to a significant decrease in system control accuracy, increased steady-state position error, and an inability to meet the dynamic accuracy requirements of precision equipment or adapt to complex operating conditions. Existing inventions have improved upon the simple dual-closed-loop PI control method for synchronous motors. For example, the invention disclosed in CN119995446A, "A Vector Control Method for Permanent Magnet Synchronous Motor with Intelligent Optimization of Speed ​​Loop PI Controller Parameters," uses an intelligent optimization algorithm (ISOA) to automatically find the optimal PI controller parameters, thereby achieving stronger robustness, improved dynamic accuracy and response, and enhanced adaptability to complex operating conditions. However, its control architecture is essentially still a high-performance feedback control system and does not employ an active disturbance observation and compensation mechanism. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a point-to-point position servo control system based on disturbance observation and compensation, which is used to realize the operation control of permanent magnet motor by adopting a dual-loop position servo system with disturbance torque observer and additional acceleration feedback.

[0005] To address the aforementioned technical problems, this invention provides a point-to-point position servo control system based on disturbance observation and compensation, comprising a position loop PD controller, a current loop control module, and a disturbance observation and compensation module. An encoder position sensor detects the rotor position of a permanent magnet synchronous motor to obtain a position signal. Position signal and quadrature axis current feedback value Acceleration observations are obtained as input to the disturbance observation and compensation module. and disturbance current compensation value ; given position instruction Subtract position signal After obtaining the position error signal, the position loop PD controller outputs the initial setpoint value of the q-axis current. The initial setpoint of the q-axis current Subtract acceleration observations Then add the disturbance current compensation value. After obtaining disturbance compensation shaft current Direct-axis current setpoint and after disturbance compensation shaft current The control signal for the permanent magnet synchronous motor is generated through the current loop control module.

[0006] As an improvement to the point-to-point position servo control system based on disturbance observation and compensation of the present invention:

[0007] The processing method of the position loop PD controller is as follows:

[0008] (1)

[0009] Among them, is Proportional gain, It is the differential gain. This represents the transfer function of the position loop PD controller, where s represents the Laplace operator. This indicates the position error signal.

[0010] As a further improvement to the point-to-point position servo control system based on disturbance observation and compensation of the present invention:

[0011] The processing method of the disturbance observation and compensation module is as follows:

[0012] (6)

[0013] in, To perturb the observer bandwidth, For the speed observer bandwidth, To compensate for acceleration gain, For the calibration process, For rotational inertia, Angular velocity, This is the quadrature-axis current feedback value. This is the torque coefficient.

[0014] As a further improvement to the point-to-point position servo control system based on disturbance observation and compensation of the present invention:

[0015] The processing method of the current loop control module is as follows:

[0016] (1) After disturbance compensation shaft current Subtract quadrature axis current feedback value Obtain the quadrature-axis current error value and the direct-axis current setpoint. Subtract the direct-axis current feedback value The direct-axis current error value is obtained; then the quadrature-axis current error value and the direct-axis current error value are input into the current loop PI controller to obtain the quadrature-axis voltage. and direct axis voltage ;

[0017] (2) Quadrature axis voltage and direct axis voltage The PARK converter module and vector control module output six PWM signals as inputs to the inverter circuit, controlling the switching transistors of the inverter circuit to control the operation of the permanent magnet synchronous motor.

[0018] (3) The two-phase stator current of the permanent magnet synchronous motor in the three-phase coordinate system is acquired by the Hall current sensor. and Two-phase stator current and The quadrature-axis current feedback value is obtained sequentially through the Clark transformation module and the PARK inverse transformation module. and direct-axis current feedback value .

[0019] As a further improvement to the point-to-point position servo control system based on disturbance observation and compensation of the present invention:

[0020] The control algorithm of the current loop PI controller is as follows:

[0021] (7)

[0022] in, This represents the gain parameter of the current loop PI controller.

[0023] The beneficial effects of this invention are mainly reflected in:

[0024] 1. The presence of motor torque fluctuations in traditional dual-loop servo control systems directly affects the system's positioning accuracy. To reduce the interference of torque changes on the system's speed and position response, this invention employs a dual-loop position servo system with a disturbance torque observer and acceleration feedback. The proposed position loop PD controller's position algorithm is based on a dual-loop controller consisting of an outer position loop and an inner current loop, and is improved by using a disturbance torque observer with a low-pass filter and additional acceleration feedback. The torque current compensation amount is obtained from the observation results of the disturbance torque observer and used to optimize the setpoint of the current loop control module. The additional acceleration feedback improves the anti-interference capability of the motion control system.

[0025] 2. This invention improves control accuracy by observing and canceling disturbances in real time, thus blocking their impact on position error. It also enhances anti-disturbance capabilities and adapts to complex operating conditions by compensating for various disturbances.

[0026] 3. By adding a disturbance observation and compensation module, this invention effectively reduces the system's high dependence on controller gain, achieving the goal of coexisting fast response and low overshoot. Attached Figure Description

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the point-to-point position servo control system based on disturbance observation and compensation according to the present invention.

[0029] Figure 2 This is a schematic diagram of the disturbance observation and compensation module of the present invention;

[0030] Figure 3 This invention relates to a point-to-point position servo control system based on disturbance observation and compensation, which uses a sinusoidal wave position signal with a frequency of 1 rad / s and K... a Position response curve under the condition of =3;

[0031] Figure 4 for Figure 3 A magnified view of region 1 in the image;

[0032] Figure 5The figure shows the position response curve of the point-to-point position servo control system based on disturbance observation and compensation of the present invention under the condition of frequency variation of sinusoidal given position signal;

[0033] Figure 6 The image shows the position response curves under loading and unloading conditions using the traditional dual-loop control method.

[0034] Figure 7 The position response curve of the point-to-point position servo control system based on disturbance observation and compensation of the present invention under loading and unloading conditions;

[0035] Figure 8 for Figure 7 A magnified view of region 1 in the image;

[0036] Figure 9 for Figure 7 An enlarged view of region 2 in the image. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0038] Example 1: A point-to-point position servo control system based on disturbance observation and compensation, such as... Figure 1 As shown, it includes three parts: a position loop PD controller, a current loop control module, and a disturbance observation and compensation module. The current loop control module includes a current loop PI controller, a PARK conversion module, a vector control module, an inverter circuit, a Clark conversion module, and a PARK inverse conversion module.

[0039] The encoder position sensor detects the position of the permanent magnet synchronous motor rotor to obtain the position signal. Position signal and quadrature-axis current feedback value As input to the disturbance observation and compensation module, acceleration observation values ​​are obtained. and disturbance current compensation value At the same time, a position command is given. Subtract position signal The position error signal is used as the input to the position loop PD controller, and the initial setpoint of the q-axis current output by the position loop PD controller is... Subtract acceleration observations Then add the disturbance current compensation value. Afterwards, the disturbance-compensated result was obtained. shaft current Direct-axis current setpoint and after disturbance compensation shaft current The control signal for the permanent magnet synchronous motor is then generated through the current loop control module. Specifically:

[0040] 1. Position Loop PD Controller

[0041] Given position instructions Subtract position signal The position error signal is obtained as the input signal of the position loop PD controller, that is... . The signal is obtained by detecting the position of the motor rotor using an encoder position sensor.

[0042] The output signal is the initial setpoint of the q-axis current. The algorithm for the position loop PD controller is as follows:

[0043] (1)

[0044] Among them, is Proportional gain is used to quickly reduce position errors; It is the differential gain, used to suppress overshoot and improve dynamic response. This represents the transfer function of the position loop PD controller, where s represents the Laplace operator. This indicates the position error signal.

[0045] 2. Disturbance Observation and Compensation Module

[0046] Disturbance observation and compensation module, such as Figure 2 As shown, the input signal is a position signal. and quadrature axis current feedback value The output signal is the acceleration observation value. and disturbance current compensation value Given the actual quadrature-axis current. After torque coefficient Obtain electromagnetic torque That is, electromagnetic torque The formula is as follows:

[0047] (2)

[0048] Subsequently electromagnetic torque The calculation is divided into the following two paths:

[0049] 1) Input position signal go through Obtaining inertial torque The inertial torque With electromagnetic torque The difference signal after torque balance is obtained by comparison (containing comprehensive information on acceleration and disturbance), i.e., the total disturbance torque. The torque balance equation for a permanent magnet synchronous motor is as follows:

[0050] (3)

[0051] in, For rotational inertia, Angular velocity, This represents the total disturbance torque.

[0052] The difference signal is then passed through a low-pass observer. Obtain the disturbance torque observation value ,in, The observer bandwidth determines the observation response speed. Disturbance torque observation value. go through Converted into disturbance current compensation value ,Right now:

[0053] (4)

[0054] in, The torque coefficient, , is the proportionality coefficient between motor torque and quadrature-axis current, reflecting the motor's ability to convert current into torque.

[0055] 2) Electromagnetic torque Compared with the observed disturbance torque After comparison The link obtains angular acceleration According to the dynamic equations, the angular acceleration is as follows:

[0056] (5)

[0057] angular acceleration go through After calculation and then through The correction process converts it into a disturbance current compensation value from acceleration observations. Its physical meaning is the additional current required to generate that angular acceleration. The correction element... Used to correct model errors, when the actual parameters of the motor (e.g., moment of inertia) are... Torque coefficient When there is a deviation between the observed acceleration and the model assumptions, this step can compensate for the deviation, making the acceleration observations and disturbance current estimates more accurate. It is typically designed as a lead compensator or a low-pass filter.

[0058] The complete algorithm for the disturbance observation and compensation module is as follows:

[0059] (6)

[0060] in, To perturb the observer bandwidth, For the speed observer bandwidth, To compensate for acceleration gain, Used to adjust the compensation intensity. This is a calibration process.

[0061] The initial setpoint of the q-axis current output by the position loop PD controller. Subtract acceleration observations To obtain the quadrature-axis current before compensation Subsequently, quadrature axis current Superimposed disturbance current compensation value After obtaining the disturbance compensation shaft current As one of the inputs to the current loop control module.

[0062] 3. Current loop control module (1) shaft current Subtract the actual quadrature axis current feedback value The quadrature-axis current error value is obtained. The permanent magnet motor uses... Vector control method, therefore the direct-axis current setpoint Subtract the direct-axis current feedback value The direct-axis current error value is obtained. The quadrature-axis current error value and the direct-axis current error value are then input into the current loop PI controller to obtain the quadrature-axis voltage. and direct axis voltage .

[0063] The control algorithm of the current loop PI controller is as follows:

[0064] (7)

[0065] in, This represents the gain parameter of the current loop PI controller.

[0066] (2) Quadrature axis voltage and direct axis voltage The stator voltage components in the two-phase net value coordinate system are output by the PARK transformation module. , The vector control module is based on the stator voltage components. , The inverter circuit outputs six PWM signals with corresponding pulse widths as inputs to the inverter circuit. The PWM signals control the switching transistors through the inverter circuit, thereby controlling the operation of the permanent magnet synchronous motor.

[0067] (3) The two-phase stator current of the permanent magnet synchronous motor in the three-phase coordinate system is obtained by acquiring current signals through two Hall current sensors. and Two-phase stator current and The quadrature-axis current feedback value is obtained sequentially through the Clark transformation module and the PARK inverse transformation module. and direct-axis current feedback value .

[0068] The PARK conversion module, vector control module, inverter circuit, Clark conversion module, and PARK inverse conversion module involved in this invention are all existing technologies in traditional permanent magnet synchronous motor servo control systems. This is a concise textual description of the invention, and the specific implementation structure and principle will not be described further.

[0069] 4. Torque control principle of permanent magnet synchronous motor

[0070] exist In the coordinate axis, the electromagnetic torque of the motor is:

[0071] (8)

[0072] in, , These are direct-axis inductors and quadrature-axis inductors, respectively. , These are the direct-axis current feedback values ​​and quadrature-axis current feedback values ​​in the rotating coordinate system; The magnetomotive force generated by the rotor permanent magnet; This represents the number of pole pairs of the motor.

[0073] use Magnetic field orientation control method, design of permanent magnet synchronous motor And when there are p pairs of poles, the electromagnetic torque equation can be simplified to: Therefore, the quadrature-axis current setpoint output by the position loop PD controller can be determined. It can effectively control the torque of the permanent magnet motor. The rotor position signal is obtained by encoder and compared with the position setpoint to obtain the position error value. This error value is used as the input value of the position loop PD controller, thereby realizing the control of the rotor position of the permanent magnet motor.

[0074] 5. Experiment

[0075] To verify the practicality and advantages of the proposed position servo control system based on disturbance observation and compensation, experiments were conducted on a DSP-based digital servo permanent magnet synchronous motor system platform. The experimental platform included: a host computer, an inverter, a servo controller, a power supply, a permanent magnet synchronous motor, and speed and torque sensors; the test power supply was AC 380V at 50Hz. After the host computer issued commands, the DSP-based servo controller received real-time feedback from the position / speed sensors (such as encoders) and torque sensors, and executed a field-oriented control (FOC) algorithm. This algorithm accurately calculated the PWM signal through multi-level closed-loop (position, speed, current) and coordinate transformation, driving the inverter to control the permanent magnet synchronous motor. Data throughout the process could be monitored and recorded in real time by the host computer.

[0076] The design parameter values ​​for the position servo control system based on disturbance observation and compensation in this invention are selected as follows: , , , , , Appendix Figure 3 , Figure 4 and Figure 5 These are the experimental results. Among them, the appendix... Figure 3 This indicates that at a given position signal with a frequency of 1 rad / s sine wave, K a When =3, the time between the display response and the reference position signal is 1ms. Figure 4 for Figure 3 A magnified view of region 1 is shown. The results demonstrate that the proposed position-loop PD controller achieves the expected position tracking performance, with a significant reduction in steady-state position error. Compared to traditional systems, this invention effectively suppresses steady-state errors caused by torque fluctuations and external disturbances by estimating and compensating for disturbance torque in real time through a disturbance observation and compensation module. This solves the problem of large steady-state errors in traditional dual-closed-loop PI control systems, enabling them to adapt to complex operating conditions. (Appendix) Figure 5 This paper presents the position response waveform obtained using the proposed position servo control system based on disturbance observation and compensation under a sinusoidal position signal with varying frequency. Given a position command... The frequency was initially set to 1 rad / s, increased to 2 rad / s at 11 s, and further increased to 10 rad / s at 16 s. Clearly, even with changes in the reference frequency, the position output signal can quickly track the reference signal. This demonstrates the system's strong robustness under parameter variations and frequency fluctuations. Thanks to the acceleration feedback and disturbance observation and compensation modules, the system's dependence on the controller's high gain is reduced, achieving the goal of fast response and low overshoot.

[0077] Under the same experimental conditions, Figure 6The figure shows the position response curves of the traditional dual-loop control method under loading and unloading conditions. Experiments show that the traditional dual-closed-loop PI control system exhibits a large steady-state error and a long recovery time when there is a disturbance, and is prone to oscillation under high-frequency input. Figure 7 The position response diagram of the position servo control system based on disturbance observation and compensation of the present invention under loading and unloading conditions is used. Figure 8 and Figure 9 They are respectively Figure 7 Enlarged display of regions 1 and 2 in the image. Figures 7-9 The results show that the steady-state error and recovery time exhibited by the system under disturbances are improved compared to traditional dual-loop experiments. This invention, by integrating a disturbance observation and compensation module, not only improves dynamic performance but also significantly enhances the system's anti-interference capability and stability, solving the problem described in the background art where traditional systems cannot meet the dynamic accuracy requirements of precision equipment.

[0078] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A point-to-point position servo control system based on disturbance observation and compensation, characterized in that: The system includes a position loop PD controller, a current loop control module, and a disturbance observation and compensation module. The encoder position sensor detects the rotor position of the permanent magnet synchronous motor to obtain the position signal. Position signal and quadrature axis current feedback value Acceleration observations are obtained as input to the disturbance observation and compensation module. and disturbance current compensation value ; given position instruction Subtract position signal After obtaining the position error signal, the position loop PD controller outputs the initial setpoint value of the q-axis current. The initial setpoint of the q-axis current Subtract acceleration observations Then add the disturbance current compensation value. After obtaining disturbance compensation shaft current Direct-axis current setpoint and after disturbance compensation shaft current The control signal for the permanent magnet synchronous motor is generated through the current loop control module.

2. The point-to-point position servo control system based on disturbance observation and compensation according to claim 1, characterized in that: The processing method of the position loop PD controller is as follows: (1) Among them, is Proportional gain, It is the differential gain. This represents the transfer function of the position loop PD controller, where s represents the Laplace operator. This indicates the position error signal.

3. A point-to-point position servo control system based on disturbance observation and compensation according to claim 2, characterized in that: The processing method of the disturbance observation and compensation module is as follows: (6) in, To perturb the observer bandwidth, For the speed observer bandwidth, To compensate for acceleration gain, For the calibration process, For rotational inertia, Angular velocity, This is the quadrature-axis current feedback value. This is the torque coefficient.

4. A point-to-point position servo control system based on disturbance observation and compensation according to claim 3, characterized in that: The processing method of the current loop control module is as follows: (1) After disturbance compensation shaft current Subtract quadrature axis current feedback value Obtain the quadrature-axis current error value and the direct-axis current setpoint. Subtract the direct-axis current feedback value The direct-axis current error value is obtained; then the quadrature-axis current error value and the direct-axis current error value are input into the current loop PI controller to obtain the quadrature-axis voltage. and direct axis voltage ; (2) Quadrature axis voltage and direct axis voltage The PARK converter module and vector control module output six PWM signals as inputs to the inverter circuit, controlling the switching transistors of the inverter circuit to control the operation of the permanent magnet synchronous motor. (3) The two-phase stator current of the permanent magnet synchronous motor in the three-phase coordinate system is acquired by the Hall current sensor. and Two-phase stator current and The quadrature-axis current feedback value is obtained sequentially through the Clark transformation module and the PARK inverse transformation module. and direct-axis current feedback value .

5. A point-to-point position servo control system based on disturbance observation and compensation according to claim 4, characterized in that: The control algorithm of the current loop PI controller is as follows: (7) in, This represents the gain parameter of the current loop PI controller.

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