Self-adaptive sliding mode speed control method for multi-section linear motor

Abstract

The invention relates to the technical field of linear motor control, and discloses a multi-stage linear motor adaptive sliding mode speed control method, which comprises the following steps of: constructing a kinetic equation of a linear motor based on operation parameters of the linear motor; based on the kinetic equation, the running speed of the linear motor is divided into a low-speed interval, a medium-speed interval and a high-speed interval; and a speed interval switching mechanism is designed, and when the speed interval of the linear motor is switched, control parameters are calculated and adjusted based on the operation parameters of the linear motor, so that smooth transition of a control strategy is realized. Through the optimized sliding mode control surface design, accurate adjustment of input signals of the linear motor is achieved, it is ensured that the linear motor can be rapidly stabilized to the target speed during high-speed operation, and meanwhile precision is maintained in the low-speed interval and the medium-speed interval.

Description

Technical Field

[0001] The present invention relates to the technical field of linear motor control, and particularly to a multi-segment linear motor adaptive sliding mode speed control method. Background Technique

[0002] In the field of linear motor control, especially the control of linear motors, with the improvement of industrial automation and precision control requirements, how to accurately adjust the speed and position of linear motors has become a key technical challenge. Traditional linear motor control methods, such as PID control (Proportional-Integral-Derivative control), fuzzy control, and adaptive control, have been widely applied to linear motor control. However, when facing different load conditions, speed changes, and external disturbances, these control methods often have problems such as slow response, overshoot, and instability. Especially when the speed or load of the linear motor changes greatly, traditional control methods may not be able to effectively ensure the stable and rapid response of the linear motor in each speed range.

[0003] A linear motor is a linear motor that works based on the principle of electromagnetic induction. Its characteristic is linear motion and is often used for precision position control. When traditional control strategies are applied to linear motors, they often face problems such as the accumulation of speed and position errors, insufficient response speed, and poor stability. In order to meet the requirements of higher precision and dynamic response, improving control algorithms has become an important research direction in the current field.

[0004] Currently, control strategies based on sliding mode control (SMC) show strong robustness in dynamic systems and can effectively deal with parameter uncertainties and external disturbances in the system. Sliding mode control achieves precise control by designing a suitable control surface so that the system can operate stably on the control surface. However, in practical applications, especially in linear motor speed control, sliding mode control still faces challenges in aspects such as control surface design, interval switching, and gain adjustment. In particular, the control strategy during the switching process between different speed intervals of the linear motor needs to be more meticulous and precise. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-segment linear motor adaptive sliding mode speed control method to solve the problems raised in the above background technique.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A multi-segment linear motor adaptive sliding mode speed control method, the method includes: Based on the operating parameters of the linear motor, construct the dynamic equation of the linear motor, where the operating parameters include current, speed, position, friction force, rotational inertia, back electromotive force, mass, driving force, voltage, inductance, and resistance; Based on the dynamic equation, the operating speed of the linear motor is divided into a low-speed range, a medium-speed range, and a high-speed range; Within the low-speed range, the operating parameters of the linear motor are collected in real time, the control error of the linear motor is calculated, the amplitude and direction of the input signal of the linear motor are adjusted, and the control parameters of the low-speed range are adjusted. The input signal is the control input of the linear motor; Within the medium-speed range, the operating parameters of the linear motor are collected in real time, and the control parameters of the medium-speed range are adjusted according to the response characteristics of the linear motor within the medium-speed range; Within the high-speed range, a sliding mode control surface is designed, the control input is calculated using the deviation on the sliding mode control surface, and the amplitude of the input signal of the linear motor is adjusted to make the state of the linear motor tend to zero along the sliding mode control surface; A speed range switching mechanism is designed. When the speed range of the linear motor switches, the control parameters are calculated and adjusted based on the operating parameters of the linear motor to achieve a smooth transition of the control strategy.

[0007] Preferably, the construction of the dynamic equation of the linear motor includes By analyzing the relationship between the driving force and the frictional force of the linear motor, the relationship between the acceleration of the linear motor and the state of the linear motor is described, and the kinematic equation of the linear motor is derived; By Kirchhoff's voltage law, combined with the operating parameters, the relationship between current and voltage is described, and the electrical equation of the linear motor is derived; The kinematic equation and the electrical equation of the linear motor are combined to derive the dynamic equation of the linear motor.

[0008] Preferably, the dynamic equation of the linear motor is expressed as

[0009] where represents the input voltage, represents the back electromotive force, represents the current, inductance, represents the resistance, represents the acceleration, represents the rotational inertia of the linear motor, represents the linear motor constant, represents the frictional force.

[0010] Preferably, the division of the operating speed of the linear motor into a low-speed range, a medium-speed range, and a high-speed range includes Calculating the acceleration of the linear motor according to the dynamic equation , integrating the acceleration to obtain the speed of the linear motor ; When the speed of the linear motor When the speed is less than the set first speed threshold, it is determined that the linear motor is in the low-speed range; When the speed of the linear motor is greater than or equal to the set first speed threshold and less than or equal to the set second speed threshold, it is determined that the linear motor is in the medium-speed range; When the speed of the linear motor is greater than the set second speed threshold, it is determined that the linear motor is in the high-speed range.

[0011] Preferably, for adjusting the control parameters in the low-speed range, the input signal is the control input of the linear motor, including According to the operation parameters collected in real time, calculate the speed error and position error of the linear motor in the low-speed range. The speed error is the difference between the target speed and the actually measured speed, and the position error is the difference between the target position and the actually measured position; Input the speed error and position error into a PID controller for calculating the control signal; The PID controller calculates the outputs of the proportional part, integral part, and derivative part. The proportional part adjusts the control signal according to the magnitude of the error, the integral part adjusts the output according to the accumulation of the error, and the derivative part adjusts the output according to the rate of change of the error; Adjust the amplitude and direction of the input signal of the linear motor through the adjustment amount output by the PID controller.

[0012] Preferably, the control parameters for adjusting the medium-speed range include According to the operation parameters collected in real time, calculate the speed error and position error of the linear motor in the medium-speed range; Convert the calculated speed error and position error into fuzzy language through an adaptive control algorithm to generate fuzzy control rules and adjust the amplitude of the input signal of the linear motor.

[0013] Preferably, adjusting the amplitude of the input signal of the linear motor includes Determine the speed error and position error of the linear motor and define the sliding mode control surface; The sliding mode control surface is expressed as

[0014] Wherein, represents the sliding mode control surface, is the weight coefficient, represents the position error, represents the speed error; At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero; The deviation is expressed as

[0015] Among them, represents the deviation of the sliding mode control surface, represents the time derivative of the weight coefficient, and are respectively the time derivatives of the speed error and the position error; If , it indicates that the linear motor has been operating stably along the sliding mode control surface, and the state has approached the target state; if , continue to adjust the control input to make the state of the linear motor converge along the sliding mode control surface; Through the sliding mode control algorithm, according to the deviation on the sliding mode control surface, generate the control input ; The said control input is expressed as,

[0016] Among them, is the control gain of the deviation of the sliding mode control surface, representing the strength of the controller, is the sign function of the sliding mode control surface, is the control gain of the time derivative of the sliding mode control surface; According to the control input , adjust the input current or the input voltage of the linear motor in real time, which is expressed as,

[0017]

[0018] Among them, and are the gain coefficients of voltage and current, representing the adjustment range of the input signal of the linear motor.

[0019] Preferably, the said speed interval switching mechanism includes, When the real-time speed of the linear motor crosses the interval boundary defined by the first speed threshold and the second speed threshold, trigger the switching mechanism; When the linear motor switches to different speed intervals, design a smooth transition mechanism, and adjust the control gain according to the speed interval switching and the current speed error and position error of the linear motor.

[0020] Compared with the prior art, the beneficial effects of the present invention are: By combining the advantages of sliding mode control and PID control, the control method of the present invention designs a multi-segment speed control strategy. This method designs different control strategies for three different speed ranges: low speed, medium speed, and high speed, ensuring that the linear motor can operate stably and accurately within each speed range. Especially in the high-speed range, the introduction of sliding mode control greatly improves the robustness of the system, enabling the linear motor to reach the target speed quickly and accurately, while avoiding the overshoot and oscillation phenomena that may be caused by traditional PID control.

[0021] By collecting the operating parameters of the linear motor in real time and calculating the error based on the feedback signal, the present invention can dynamically adjust the control gain to adapt to different working states of the linear motor. This control method based on the real-time feedback of the linear motor can smoothly adjust the control strategy when the linear motor crosses the speed range, avoiding sudden changes in the control input during range switching, and ensuring the smooth transition and stable operation of the system. Specifically, during the transition from low speed to medium speed or from medium speed to high speed, the control gain can be automatically adjusted to provide a faster response; while during the transition from high speed to medium speed or from medium speed to low speed, the reduction of the gain can effectively suppress the over-response and avoid system oscillation.

[0022] Through the optimized design of the sliding mode control surface, the present invention realizes the precise adjustment of the input signal of the linear motor, ensuring that the linear motor can quickly stabilize to the target speed during high-speed operation, while maintaining accuracy in the low-speed and medium-speed ranges. Through this multi-segment control method, the operation of the linear motor is more stable and efficient, while improving the adaptability and robustness of the system, and can meet the requirements under different loads and working conditions. In addition, the control method of the present invention provides an efficient and stable control scheme for the linear motor through a smooth range switching mechanism, without increasing complexity, and solves many deficiencies in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a step diagram of a multi-segment linear motor adaptive sliding mode speed control method according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Example 1, referring to Figure 1 , which is the first embodiment of the present invention. This embodiment provides a multi-segment linear motor adaptive sliding mode speed control method, including: Based on the operating parameters of the linear motor, construct the dynamic equation of the linear motor, where the operating parameters include current, speed, position, friction force, rotational inertia, back electromotive force, mass, driving force, voltage, inductance, and resistance; Based on the dynamic equation, divide the operating speed of the linear motor into a low-speed range, a medium-speed range, and a high-speed range; In the low-speed range, collect the operating parameters of the linear motor in real time, calculate the control error of the linear motor, adjust the amplitude and direction of the input signal of the linear motor, and adjust the control parameters in the low-speed range. The input signal is the control input of the linear motor, such as current or voltage, and the signal determines the working state of the motor; In the medium-speed range, collect the operating parameters of the linear motor in real time, and adjust the control parameters in the medium-speed range according to the response characteristics of the linear motor in the medium-speed range; In the high-speed range, design a sliding mode control surface, calculate the control input using the deviation on the sliding mode control surface, and adjust the amplitude of the input signal of the linear motor to make the state of the linear motor tend to zero along the sliding mode control surface; Design a speed range switching mechanism. When the speed range of the linear motor switches, calculate and adjust the control parameters based on the operating parameters of the linear motor to achieve a smooth transition of the control strategy.

[0026] The construction of the dynamic equation of the linear motor includes analyzing the relationship between the driving force and the friction force of the linear motor, describing the relationship between the acceleration of the linear motor and the state of the linear motor, and deriving the kinematic equation of the linear motor; Through Kirchhoff's voltage law, combined with the operating parameters, describe the relationship between current and voltage, and derive the electrical equation of the linear motor; Combine the kinematic equation and the electrical equation of the linear motor to derive the dynamic equation of the linear motor.

[0027] The dynamic equation of the linear motor is expressed as

[0028] where represents the input voltage, represents the back electromotive force, represents the current, inductance, represents the resistance, represents the acceleration, represents the rotational inertia of the linear motor, represents the linear motor constant, represents the friction force.

[0029] The division of the operating speed of the linear motor into a low-speed range, a medium-speed range, and a high-speed range includes calculating the acceleration of the linear motor according to the dynamic equation , integrating the acceleration to obtain the speed of the linear motor ; When the speed of the linear motor is less than the set first speed threshold, it is determined that the linear motor is in the low-speed range; When the speed of the linear motor is greater than or equal to the set first speed threshold and less than or equal to the set second speed threshold, it is determined that the linear motor is in the medium-speed range; When the speed of the linear motor is greater than the set second speed threshold, it is determined that the linear motor is in the high-speed range.

[0030] The adjustment of the low-speed range control parameters includes calculating the speed error and position error of the linear motor in the low-speed range according to the real-time collected operating parameters. The speed error is the difference between the target speed and the actually measured speed, and the position error is the difference between the target position and the actually measured position; Input the speed error and position error into the PID controller to calculate the control signal; The PID controller calculates the outputs of the proportional part, integral part, and derivative part. The proportional part adjusts the control signal according to the magnitude of the error, the integral part adjusts the output according to the accumulation of the error, and the derivative part adjusts the output according to the rate of change of the error; Adjust the amplitude and direction of the input signal of the linear motor through the adjustment amount output by the PID controller.

[0031] The adjustment of the medium-speed range control parameters includes calculating the speed error and position error of the linear motor in the medium-speed range according to the real-time collected operating parameters; Convert the calculated speed error and position error into fuzzy language through the adaptive control algorithm, generate fuzzy control rules, and adjust the amplitude of the input signal of the linear motor.

[0032] The adjustment of the amplitude of the input signal of the linear motor includes determining the speed error and position error of the linear motor and defining the sliding mode control surface; The sliding mode control surface is expressed as

[0033] where is the weight coefficient, represents the position error, represents the speed error; At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero; The deviation is expressed as

[0034] Among them, represents the deviation of the sliding mode control surface, represents the time derivative of the weight coefficient, and are the time derivatives of the speed error and the position error respectively; If , it indicates that the linear motor has been operating stably along the sliding mode control surface and the state has approached the target state; if , continue to adjust the control input to make the state of the linear motor converge along the sliding mode control surface; Through the sliding mode control algorithm, according to the deviation on the sliding mode control surface, generate the control input ; The control input is expressed as

[0035] Among them, The control gain of the deviation of the sliding mode control surface, representing the strength of the controller, is the sign function of the sliding mode control surface, is the control gain of the time derivative of the sliding mode control surface; According to the control input , adjust the input current or the input voltage of the linear motor in real time, which is expressed as

[0036]

[0037] Among them, and are the gain coefficients of voltage and current, representing the adjustment amplitude of the input signal of the linear motor.

[0038] The speed interval switching mechanism includes that when the real-time speed of the linear motor crosses the interval boundary defined by the first speed threshold and the second speed threshold, the switching mechanism is triggered; When the linear motor switches to a different speed interval, design a smooth transition mechanism, and adjust the control gain according to the speed interval switching and the current speed error and position error of the linear motor.

[0039] Determine the key operating parameters of the linear motor, including current , speed , position , friction , rotational inertia , back electromotive force , mass , driving force , voltage , inductance and resistance . These operating parameters are used to describe the dynamic behavior of the linear motor. In particular, speed and position are the key state variables of the linear motor, and they directly affect the control strategy of the linear motor.

[0040] Derive the kinematic equation of the linear motor, considering the mass and moment of inertia of the linear motor, and through the relationship between the driving force and the frictional force of the linear motor, the acceleration equation of the linear motor is derived:

[0041] where, is the acceleration, is the driving force, is the frictional force, is the mass of the linear motor. This equation describes the relationship between the acceleration of the linear motor and the external driving force and frictional force. The driving force is generated by the current and interacts with the moment of inertia and frictional force of the linear motor through the electromagnetic torque .

[0042] Derive the electrical equation of the linear motor, and describe the relationship between the current and the voltage through Kirchhoff's voltage law (KVL):

[0043] where, is the inductance, is the resistance, is the back electromotive force, represents the differential symbol, represents the rate of change of the current with respect to time, and the current serves as the input signal of the linear motor to control the output (speed, position) of the linear motor. This equation describes how the current changes with the voltage, back electromotive force, and resistance.

[0044] Combine the electrical equation with the kinematic equation to derive the complete dynamic equation of the linear motor. The electromagnetic torque generated by the current is given by the relationship between the linear motor constant and the current:

[0045] where, is the linear motor constant, which represents the relationship between the current and the generated electromagnetic torque. The electromagnetic torque and the acceleration of the linear motor have the following relationship:

[0046] where, is the moment of inertia of the linear motor, is the acceleration, is the frictional force. Substituting the expression of the electromagnetic torque yields:

[0047] At this time, the current can be derived from the electrical equation.

[0048] Combining the electrical equation and the mechanical equation to form the complete linear motor dynamics equation. By substituting the expression of the current into the mechanical equation, the complete linear motor control equation is obtained:

[0049] where, is the input voltage, is the back electromotive force, is the current, and are the inductance and resistance respectively. This equation describes the relationship between the input voltage and the dynamic response (position, speed) of the linear motor.

[0050] When integrating, the prior art usually considers the initial conditions to determine the constants. Assume that the initial velocity of the linear motor at is , and the existing integration formula is expressed as:

[0051] where, is the integration variable, representing the change in time, is the initial velocity of the linear motor, i.e., the velocity at , represents the acceleration.

[0052] Therefore, the velocity of the linear motor is the integral result of the acceleration varying with time, and the influence of the initial velocity is considered.

[0053] The method of this embodiment transforms the linear motor dynamics equation. Starting from the dynamics equation:

[0054] This equation gives the acceleration and can be further simplified to:

[0055] Then, integrating both sides gives the velocity :

[0056] This formula clearly relates the acceleration to the dynamic inputs (voltage, current, etc.) of the linear motor. At the same time, the frictional force is also adjusted through the rotational inertia of the linear motor.

[0057] It should be noted that the method of this embodiment significantly improves the accuracy and robustness of the linear motor control system by improving the traditional linear motor control method. The traditional integral solution method usually directly relies on the integral of acceleration to obtain the velocity, and then determines the working state of the linear motor based on the velocity. However, this method faces multiple defects in practical applications. First, the traditional method usually ignores the non-linear factors inside the linear motor, such as the influence of the back electromotive force of the linear motor on the system dynamic behavior, resulting in a certain error between the solution result and the actual dynamic behavior. Second, the traditional method often has error accumulation during the integral process of acceleration. Especially when the load of the linear motor changes rapidly or the control input signal fluctuates greatly, the integral error will continuously accumulate, ultimately affecting the accuracy and stability of the linear motor speed. In addition, the traditional method divides the speed interval based on a static threshold and cannot effectively adapt to the changes of the linear motor under different working loads and dynamic environments, resulting in a slow response speed in practical applications and being unable to adjust the control strategy in real time to cope with the dynamic changes of the linear motor.

[0058] The present invention improves the traditional method. By accurately modeling the dynamic behavior of the linear motor and considering the interaction of multiple factors such as current, input voltage, back electromotive force, and frictional force, a more accurate acceleration calculation formula for the linear motor is provided. Through this formula, not only can the acceleration of the linear motor be calculated, but also the velocity of the linear motor can be calculated in real time in combination with the control input of the linear motor, and the operating state of the linear motor can be determined according to the velocity change. Compared with the traditional method, it avoids the problem of inaccurate speed prediction caused by error accumulation and provides more accurate control of the linear motor. Further, the improved linear motor control method can update the judgment criteria of the speed interval in real time and dynamically adjust the control strategy based on the actual operating state (velocity and acceleration) of the linear motor. Through this real-time feedback mechanism, the speed interval of the linear motor can be adaptively divided in practical applications, thereby improving the response speed and accuracy of the linear motor control.

[0059] In addition, by considering the non-linear characteristics of the linear motor, especially the influence of the change in the back electromotive force of the linear motor on the operating state of the linear motor, the robustness of the system is further improved. In traditional methods, the back electromotive force of the linear motor is often not fully considered, and the influence of the back electromotive force on the behavior of the linear motor is particularly significant at high rotational speeds of the linear motor. By adding the real-time change of the back electromotive force of the linear motor to the dynamic model of the present invention, the behavior of the linear motor at high speeds can be more accurately described, ensuring that the linear motor can maintain a stable operating state under rapid response. Furthermore, through the improvement of the present invention, the linear motor can adapt to voltage and current fluctuations in different speed ranges, providing fine control and avoiding the instability and control errors caused by the change in the back electromotive force in traditional methods.

[0060] It should be noted that the operating parameters of the linear motor are collected in real time, including current, speed, position, back electromotive force, and friction, etc. These operating parameters are fed back to the control system through sensors. According to the real-time data collected, the speed error and position error of the linear motor are calculated. The speed error is the difference between the target speed and the actually measured speed, and the position error is the difference between the target position and the actually measured position. The speed error and position error are used as inputs and sent to the PID controller for calculating the control signal. The PID controller calculates the outputs of the proportional, integral, and differential parts. The proportional part adjusts the control signal according to the magnitude of the error, the integral part adjusts the output according to the accumulation of the error, and the differential part adjusts the output according to the rate of change of the error. Through the adjustment amount output by the PID controller, the amplitude and direction of the input signal of the linear motor are adjusted in real time, so that the speed and position of the linear motor gradually approach the target value. When the speed error is large, the current amplitude is increased; when the speed error is small, the current amplitude is decreased to avoid excessive acceleration. According to the response characteristics of the linear motor in the low-speed range, the gain of the PID controller is adjusted in real time to adapt to the dynamic changes of the linear motor, especially when the friction and inertia are large at low speeds, ensuring that the linear motor accelerates smoothly and reduces unstable phenomena. By dynamically adjusting the parameters of the PID controller, the control process is optimized to ensure that the linear motor can start smoothly and gradually accelerate in the low-speed range.

[0061] Furthermore, in the low-speed range, the operating parameters of the linear motor are obtained in real time. Current sensors, position encoders, speed sensors, back electromotive force detectors, etc. are used to collect the operating parameters.

[0062] Using the real-time collected feedback signals, calculate the speed error of the linear motor and the position error . The speed error is calculated by comparing the target speed of the linear motor with the actually measured speed . The formula is:

[0063] The position error is calculated by comparing the target position with the actually measured position and the formula is:

[0064] The control signal is calculated by the PID controller: The speed error and the position error are input into the PID controller, and the PID control algorithm is used to adjust the input signal. The controller calculates the output of each part according to the three parts of proportional, integral, and derivative: Proportional control: Calculate the proportional part of the control signal according to the magnitude of the error.

[0065] Integral control: Calculate the output of the integral part according to the accumulation of the error to eliminate small errors that exist for a long time.

[0066] Derivative control: Adjust the output of the derivative part according to the rate of change of the error to prevent over-response of the linear motor.

[0067] According to the adjustment amount output by the PID controller, the amplitude and direction of the input signal of the linear motor are adjusted in real time. Specifically, if the speed error is large, the current amplitude is increased to provide more driving force; if the speed error is small, the current amplitude is decreased to avoid over-acceleration or oscillation.

[0068] Since the response of the linear motor in the low-speed range is slow and the influence of friction on the acceleration process is large, it is necessary to dynamically adjust the gain of the PID controller. Calculate the acceleration, speed change, and error fluctuation of the linear motor in real time, and dynamically adjust the proportional gain, integral gain, and derivative gain in the PID controller to optimize the control process. The purpose of adjusting the parameters is to enable the linear motor to accelerate gradually and reduce system instability and overshoot.

[0069] When the linear motor is affected by load changes or friction changes in the low-speed range, the control system further adjusts the control strategy by real-time monitoring of feedback information to ensure that the linear motor can operate smoothly and avoid system oscillation. The control system adjusts the gain of the PID control according to the change of the linear motor state, especially in the low-speed starting stage, to gradually increase the response speed of the system.

[0070] In the medium-speed range, since the dynamic response of the linear motor has become stable and the influence of friction and load changes is low, the control system adopts an adaptive control algorithm to adapt to the response characteristics of the medium-speed range.

[0071] According to the collected feedback signals, calculate the speed error and position error of the linear motor in the medium-speed range. Different from using PID control in the low-speed range, an adaptive control algorithm is adopted in the medium-speed range. The adaptive control algorithm dynamically adjusts the control parameters according to the current error value, acceleration, and operating state of the linear motor. In the adaptive control algorithm, the control gain is automatically adjusted through the error updated in real time and the dynamic characteristics of the system to optimize the response characteristics of the linear motor and ensure the stable operation of the linear motor in the medium-speed range.

[0072] The error signal input into the adaptive control algorithm undergoes a fuzzification process or a process of dynamically adjusting the gain, and the adjustment amplitude of the control signal is calculated in real time. Adaptive control ensures that the linear motor can adjust the amplitude of the input signal according to different load changes and dynamic disturbances through the self-regulation of the control gain. This process adjusts the acceleration state of the linear motor by changing the input current to ensure that the linear motor can stably approach the target speed and maintain within the target speed range.

[0073] According to the response characteristics of the linear motor, the control system further adjusts the direction and amplitude of the input signal of the linear motor, smoothly transitioning to the target speed, avoiding the instability caused by over-control in the low-speed range, and reducing the over-regulation or oscillation phenomenon caused by traditional PID control. The adaptive control algorithm can effectively cope with changes in load and friction, optimize the control process of the linear motor in the medium-speed range, and maintain efficient operation.

[0074] It should be noted that when the linear motor operates in the medium-speed range, the speed of the linear motor has reached a certain level, and the dynamic response of the system becomes relatively stable. Since the acceleration of the linear motor is relatively stable at this time, the influence of friction and load changes on the system is also relatively reduced. Traditional PID control may lead to overshoot or slow response. The introduction of the adaptive control algorithm enables the control system to dynamically adjust the control gain according to the operating state and error changes of the linear motor and can adapt to the response characteristics of the linear motor in real time.

[0075] Through the adaptive control algorithm, the linear motor control system can accurately adjust the speed and position error of the linear motor and dynamically adjust the control gain to optimize the acceleration and deceleration processes of the linear motor. Compared with PID control, adaptive control can avoid over-regulation during response, thereby improving the smoothness and accuracy of the linear motor.

[0076] In the medium-speed range, the response of the linear motor is relatively stable with small errors. Therefore, it is necessary to precisely control the input signal of the linear motor to avoid overshoot and unnecessary error accumulation in the system. The adaptive control algorithm optimizes the control process of the linear motor by calculating the error in real time and adjusting the gain. This means that the controller can automatically adjust the gain according to the current state of the linear motor (e.g., the magnitude and rate of change of the error), making the linear motor control system more flexible and adaptable.

[0077] By dynamically adjusting the gain, adaptive control can effectively avoid over-response and prevent the oscillation or instability that may occur in the medium-speed range with traditional PID control. The linear motor can smoothly transition to the target speed and maintain stable operation.

[0078] In the technical implementation process of the adaptive control algorithm in the medium-speed range, it not only adjusts the amplitude and direction of the control signal according to the error calculation result, but also ensures the smooth and precise change of the input signal through gain adjustment. Especially in the case of load changes and friction fluctuations, the adaptive control algorithm can provide precise adjustment to ensure the stability of the linear motor and prevent control instability caused by load fluctuations.

[0079] When the linear motor is affected by load changes or external disturbances, adaptive control can timely adjust the amplitude and direction of the input signal, enabling the linear motor to still be precisely controlled in the medium-speed range. This precise error adjustment significantly improves the stability and operating efficiency of the linear motor, reducing the non-linear instability problems that may be caused by traditional control methods.

[0080] In the medium-speed range, the traditional PID control method may lead to error accumulation and oscillation phenomena, especially when the control gain is too high. The adaptive control algorithm can adjust the control parameters in real time according to the dynamic characteristics of the linear motor operation, avoiding excessive error accumulation. As the stability of the system improves, the input signal will be smoother, thus ensuring the stable operation of the linear motor.

[0081] The suppression of error accumulation and oscillation is one of the most significant technical effects of adaptive control in the medium-speed range. By adjusting the gain in real time and optimizing the adjustment of the input signal, the linear motor can reduce error accumulation and maintain the smooth and stable operation of the system. The traditional PID control method cannot effectively handle this dynamic change.

[0082] In the medium-speed range, sensors (such as current sensors, position encoders, speed sensors, back electromotive force measuring instruments) are used to collect the operation parameter data of the linear motor in real time. The collected operation parameters are input into the control system in real time through the data acquisition module for subsequent feedback calculation.

[0083] Compare the actual speed and the target speed of the linear motor collected in real time to calculate the speed error; similarly, calculate the position error by comparing the actual position and the set target position of the linear motor, and input the error value as a feedback signal into the adaptive control algorithm for subsequent processing.

[0084] Input the calculated speed error and the position error into the adaptive control algorithm. The adaptive control algorithm mainly performs two operations in this process: Convert the calculated speed error and position error into fuzzy language to generate fuzzy control rules (for example, "large error" corresponds to "increase current", and "small error" corresponds to "decrease current").

[0085] Dynamically adjust the control gain according to the actual operating state of the linear motor (such as acceleration, error change trend, etc.) so that the adjustment amplitude of the control signal (voltage or current) matches the system response requirements.

[0086] The adaptive control algorithm calculates and outputs the control gain to adjust the input signal of the linear motor. The adjustment of the gain is based on the dynamic characteristics of the linear motor, taking into account factors such as friction, load, and rotational inertia of the linear motor in the medium-speed range.

[0087] Dynamically adjust the gain: When the operating state of the linear motor changes (such as load change, friction fluctuation, etc.), the adaptive control algorithm adjusts the control gain according to the real-time calculated feedback information to keep the linear motor running stably within the target speed range.

[0088] Adjust the amplitude of the input signal of the linear motor (such as current or voltage ) according to the optimized control gain and error feedback to ensure that the linear motor can run smoothly within the target speed range.

[0089] The control system will gradually adjust the input signal of the linear motor according to the magnitude and change trend of the current error, avoid excessive acceleration or deceleration, and ensure that the linear motor accelerates smoothly and approaches the target speed.

[0090] Dynamically update the control strategy according to the response characteristics of the linear motor in the medium-speed range. The control system continuously adjusts the control parameters (such as proportional gain, integral time, derivative time, etc.) and optimizes the control strategy in real time according to the current state of the linear motor and load changes.

[0091] For a large error, the control system accelerates the linear motor by increasing the current; when the error decreases, the system decreases the current to avoid excessive acceleration and ensure the stability of the system.

[0092] The control system continuously monitors the operating state of the linear motor and adjusts the control parameters through a feedback mechanism. The control parameters of the linear motor (including current amplitude, gain, etc.) will be optimized and adjusted according to the operating state of the linear motor throughout the medium-speed range to ensure that the linear motor can operate stably under different loads and dynamic change conditions.

[0093] In the medium-speed range, by using an adaptive control algorithm, the linear motor control system can automatically adjust the control gain according to the error value feedback in real time and the dynamic response characteristics of the linear motor, and optimize the operation of the linear motor. This control method dynamically adjusts the amplitude of the input signal according to the actual working state of the linear motor to ensure that the linear motor can maintain the target speed in the medium-speed range. The adaptive control algorithm can automatically adjust the control parameters when the load changes or the friction fluctuates, enabling the linear motor to smoothly follow the set speed and effectively adapt to system changes.

[0094] In addition, the adaptive control algorithm adjusts the direction and amplitude of the input signal by calculating the speed error and position error in real time, avoiding the over-regulation and oscillation phenomena that may be caused by traditional PID control. During the response process of the linear motor, the control system can optimize the control signal according to the acceleration and speed changes of the linear motor, reduce error accumulation, improve the robustness of the system, and enhance the precise control ability of the linear motor in the medium-speed range.

[0095] In the high-speed range, a sliding mode control surface is designed based on the speed error and position error of the linear motor. The sliding mode control surface forms a state surface through the combination of the speed and position errors of the linear motor, and calculates the deviation between the error value and the sliding mode control surface.

[0096] The calculated error deviation is used as the input to generate the deviation amount of the sliding mode control surface, and the input signal of the linear motor is adjusted through this deviation. The sliding mode control algorithm adjusts the current or voltage of the linear motor according to the magnitude of the deviation to ensure that the state of the linear motor tends to zero along the sliding mode control surface.

[0097] The core of the sliding mode control surface design is to make the control error tend to zero to ensure the stable operation of the linear motor in the high-speed range. By adjusting the amplitude of the input signal of the linear motor, the oscillation and error of the linear motor in the high-speed state are reduced, so that when the linear motor reaches the set target speed, the system can quickly and stably converge.

[0098] In the high-speed range, the sliding mode control surface can adaptively adjust the amplitude of the input signal according to the dynamic response and error changes of the linear motor to ensure that the linear motor accurately maintains within the target speed range and can effectively resist external disturbances and load fluctuations.

[0099] Through the sliding mode control algorithm, the error value and the deviation of the sliding mode control surface are calculated in real time to optimize the control strategy of the linear motor, further improving the response speed and system stability of the linear motor in the high-speed range.

[0100] In the high-speed range, first calculate the speed error and position error of the linear motor. The error describes the deviation between the actual speed and the target speed, and the actual position and the target position of the linear motor.

[0101] Based on the speed error and position error, define the sliding mode control surface , which is usually expressed as:

[0102] where is the weight coefficient, which is used to adjust the relative influence of the position error and speed error on the sliding mode control surface, ensuring that the control strategy is adjusted according to the dynamic characteristics of the linear motor.

[0103] At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero: Calculate the sliding mode control surface The time derivative , that is, the deviation amount on the sliding mode control surface:

[0104] where and are the time derivatives of the speed error and position error respectively, representing the change rates of the linear motor speed and position.

[0105] If , it indicates that the linear motor has been running stably along the sliding mode control surface and the state has approached the target state; if , continue to adjust the control input to make the linear motor state converge along the sliding mode control surface.

[0106] Through the sliding mode control algorithm, according to the deviation amount on the sliding mode control surface, generate the control input . The control input is designed by the following formula:

[0107] where The control gain of the sliding mode control surface deviation, representing the strength of the controller, is the sign function of the sliding mode control surface, is the control gain of the time derivative of the sliding mode control surface.

[0108] The role of the sign function is to ensure that the direction of the control input is consistent with the direction of the error. When the deviation on the sliding mode control surface is large, the amplitude of the control input increases; conversely, the control input decreases.

[0109] According to the control input , the input current of the linear motor is adjusted in real time or the input voltage . The specific relationship is as follows:

[0110] Or:

[0111] Where and are the gain coefficients of voltage and current, representing the adjustment amplitude of the input signal of the linear motor.

[0112] Current control is applicable to occasions where precise control of the torque of the linear motor is required. Especially when the load changes greatly, current control can quickly respond and adjust the torque of the linear motor.

[0113] Voltage control is applicable to occasions where precise control of the speed of the linear motor is required. Especially in the high-speed range, when the speed accuracy requirement of the linear motor is high, using voltage control can avoid overshoot caused by excessive current.

[0114] During the operation of the linear motor, the deviation on the sliding mode control surface is continuously calculated , and the input signal of the linear motor is dynamically adjusted according to the deviation, ensuring that the state of the linear motor continuously approaches zero along the sliding mode control surface, and finally enabling the linear motor to operate stably near the set target speed.

[0115] If any disturbance or load change occurs in the high-speed range of the linear motor, the sliding mode control algorithm can adjust the amplitude and direction of the input signal of the linear motor in real time to ensure the robustness and stability of the system.

[0116] It should be noted that the weight coefficient λ is used to adjust the influence of the position error and the speed error on the sliding mode control surface. This coefficient is usually determined by the dynamic response characteristics of the linear motor, the control accuracy requirements, and the system stability. Generally, the weight coefficient λ is a positive constant that can balance the relationship between the position error and the speed error.

[0117] λ can be determined by the experimental method: First, set the initial weight coefficient, conduct experiments and observe the response effect of the linear motor in different speed ranges. If the response of the linear motor is too intense or overly oscillatory, then λ can be reduced. If there is a delay or slow convergence in the response process of the linear motor, then λ can be increased.

[0118] Theoretical derivation and optimal selection are carried out based on parameters such as the mass, inertia, and load change of the linear motor.

[0119] The coefficient value can be adjusted according to the actual application scenario and combined with other parameters of the linear motor controller for optimization to obtain the best control effect.

[0120] Furthermore, in sliding mode control, the sign function By determining the direction of the control signal, it helps the system quickly approach the sliding mode control surface and maintain its stability. The specific implementation of the sign function is as follows:

[0121] The sign function is used to calculate the direction of the linear motor control input, ensuring that the positive and negative directions of the input signal are consistent with the direction of the error. According to the positive and negative of the sliding mode control surface deviation, the control input generated by the sign function can effectively guide the state of the linear motor to converge to zero and avoid oscillation.

[0122] When the real-time speed of the linear motor crosses the boundary of the defined speed interval, the interval switching mechanism is triggered. The linear motor control system continuously monitors the speed of the linear motor, real-time collects operation parameters such as current, speed, position, back electromotive force, and friction force, and compares them with the set speed interval. By comparing the real-time speed of the current linear motor with the threshold of the speed interval, it is determined whether the linear motor crosses the interval boundary. If it crosses, the speed interval switching mechanism is triggered to perform dynamic adjustment of the control gain. The control system calculates the control gain adjustment amount based on the error values of the linear motor, such as speed error and position error, so as to adjust the control input in real time and ensure that the linear motor smoothly transitions to the new speed interval.

[0123] When the linear motor enters the medium-speed interval from the low-speed interval, the control gain is adjusted to meet the requirements of the linear motor acceleration process. The proportional gain increases to improve the response speed, enabling the linear motor to quickly respond to changes in the target speed. The integral gain increases moderately to ensure that the linear motor can eliminate long-term errors and smoothly enter the medium-speed interval. The derivative gain decreases to avoid overshoot or oscillation during the transition process and maintain the stability of the system.

[0124] When the linear motor enters the high-speed interval from the medium-speed interval, the weights of the PID controller gradually decrease, and the influence of the sliding mode control algorithm increases. The control system adjusts the amplitude of the input signal through the sliding mode control algorithm and uses the current as the main control input signal to ensure that the linear motor stably and quickly reaches the target speed within the high-speed interval. The sliding mode control surface precisely adjusts the input of the linear motor according to the changes in the speed and position errors of the linear motor to ensure that the linear motor remains stable during high-speed operation.

[0125] When the linear motor reduces from the medium-speed range to the low-speed range, the control gain gradually decreases, and the proportional gain decreases to prevent the linear motor from overresponding during deceleration. The adjustment of the integral gain and the derivative gain is gradually optimized according to the response requirements of the linear motor to avoid oscillation of the linear motor during deceleration. The derivative gain increases to help reduce the error accumulation during deceleration and maintain the stability of the linear motor.

[0126] If the linear motor jumps directly from the low-speed range to the high-speed range, a larger control adjustment is required. At this time, the proportional gain needs to be significantly increased to meet the requirements of the linear motor during acceleration. By increasing the influence of sliding mode control, the control input of current or voltage will quickly adjust the speed of the linear motor to ensure that the linear motor can operate stably in the high-speed range.

[0127] When the linear motor directly drops from the high-speed range to the low-speed range, the system needs to quickly reduce the input current or voltage, decrease the proportional gain, and increase the derivative gain so that the linear motor can decelerate smoothly and operate stably in the low-speed range. The increase in the derivative gain helps reduce the oscillation or overshoot of the linear motor during deceleration and ensures the smooth transition of the control signal.

[0128] Each time the interval switches, the control system dynamically calculates the control input based on the real-time feedback information of the linear motor, such as speed error, position error, and acceleration, and optimizes the gain to ensure that the linear motor can smoothly transition to the target speed and avoid sudden changes and instability of the control input. Throughout the process, the adjustment of the control gain is achieved through a smooth transition algorithm to ensure that the linear motor can operate efficiently and stably in the new interval each time the speed interval switches.

[0129] In this technical solution, the speed interval switching mechanism of the linear motor ensures a smooth transition between different speed intervals by smoothly adjusting the control gain. When the linear motor enters the medium-speed range from the low-speed range or from the medium-speed range to the high-speed range, the adjustment of the gain enables the linear motor to quickly respond to the target speed and maintain stability. By appropriately adjusting the proportional, integral, and derivative gains, overshoot, oscillation, and instability are avoided, while the response ability of the system is enhanced. On the contrary, when the linear motor goes from the high-speed range to the medium-speed range or from the medium-speed range to the low-speed range, the proportional gain is decreased and the derivative gain is increased to further reduce the instability of the system, ensure a smooth deceleration process, and avoid overresponse of the linear motor.

[0130] This technical solution realizes precise adjustment of linear motor control by dynamically adjusting the control input (current or voltage). The smooth transition of the control gain ensures that the linear motor does not experience severe fluctuations or instability when switching speed ranges, thereby enhancing the robustness and adaptability of the control system. Especially when the linear motor directly crosses from low speed to high speed or from high speed to low speed, the rapid adjustment of the gain ensures that the linear motor can quickly adapt to the new operating conditions and thus maintain precise and stable speed control.

[0131] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0132] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

[0133] It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solution of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention, and all of them should be covered within the scope of the claims of the present invention.

Claims

1. A multi-segment linear motor adaptive sliding mode speed control method, characterized in that: including Based on the operating parameters of the linear motor, construct the dynamic equation of the linear motor, where the operating parameters include current, speed, position, friction force, rotational inertia, back electromotive force, mass, driving force, voltage, inductance, and resistance; Based on the dynamic equation, divide the operating speed of the linear motor into a low-speed range, a medium-speed range, and a high-speed range; In the low-speed range, collect the operating parameters of the linear motor in real time, calculate the control error of the linear motor, adjust the amplitude and direction of the input signal of the linear motor, and adjust the control parameters in the low-speed range, where the input signal is the control input of the linear motor; In the medium-speed range, collect the operating parameters of the linear motor in real time, and adjust the control parameters in the medium-speed range according to the response characteristics of the linear motor in the medium-speed range; In the high-speed range, design a sliding mode control surface, calculate the control input using the deviation on the sliding mode control surface, and adjust the amplitude of the input signal of the linear motor to make the state of the linear motor tend to zero along the sliding mode control surface; Design a speed range switching mechanism. When the speed range of the linear motor switches, calculate and adjust the control parameters based on the operating parameters of the linear motor to achieve a smooth transition of the control strategy.

2. The multi-segment linear motor adaptive sliding mode speed control method according to claim 1, characterized in that: The construction of the dynamic equation of the linear motor includes By analyzing the relationship between the driving force and the friction force of the linear motor, describe the relationship between the acceleration of the linear motor and the state of the linear motor, and deduce the kinematic equation of the linear motor; Through Kirchhoff's voltage law, combined with the operating parameters, describe the relationship between current and voltage, and deduce the electrical equation of the linear motor; Combine the kinematic equation and the electrical equation of the linear motor to deduce the dynamic equation of the linear motor.

3. The multi-segment linear motor adaptive sliding mode speed control method according to claim 2, wherein: The dynamic equation of the linear motor is expressed as Among them, represents the input voltage, represents the back electromotive force, represents the current, inductance, represents the resistance, represents the acceleration, represents the rotational inertia of the linear motor, represents the linear motor constant, represents the frictional force.

4. The multi-segment linear motor adaptive sliding mode speed control method according to claim 3, wherein: The division of the operating speed of the linear motor into a low-speed range, a medium-speed range, and a high-speed range includes Calculate the acceleration of the linear motor according to the kinetic equation , and integrate the acceleration to obtain the velocity of the linear motor ; When the speed of the linear motor is less than the set first speed threshold, it is determined that the linear motor is in the low-speed range; When the speed of the linear motor is greater than or equal to the set first speed threshold and less than or equal to the set second speed threshold, it is determined that the linear motor is in the medium-speed range; When the speed of the linear motor is greater than the set second speed threshold, it is determined that the linear motor is in the high-speed range.

5. The multi-segment linear motor adaptive sliding mode speed control method according to claim 4, characterized in that: The adjustment of the control parameters in the low-speed range, where the input signal is the control input of the linear motor includes According to the operating parameters collected in real time, calculate the speed error and position error of the linear motor in the low-speed range. The speed error is the difference between the target speed and the actually measured speed, and the position error is the difference between the target position and the actually measured position; Input the speed error and position error into a PID controller to calculate the control signal; The PID controller calculates the outputs of the proportional part, integral part, and derivative part. The proportional part adjusts the control signal according to the magnitude of the error, the integral part adjusts the output according to the accumulation of the error, and the derivative part adjusts the output according to the rate of change of the error; Adjust the amplitude and direction of the input signal of the linear motor through the adjustment amount output by the PID controller.

6. The multi-segment linear motor adaptive sliding mode speed control method according to claim 5, wherein: The adjustment of the control parameters in the medium-speed range includes According to the operating parameters collected in real time, calculate the speed error and position error of the linear motor in the medium-speed range; Convert the calculated speed error and position error into fuzzy language through an adaptive control algorithm, generate fuzzy control rules, and adjust the amplitude of the input signal of the linear motor.

7. The multi-segment linear motor adaptive sliding mode speed control method according to claim 6, wherein: The adjustment of the amplitude of the input signal of the linear motor includes Determine the speed error and position error of the linear motor and define the sliding mode control surface; The sliding mode control surface is expressed as Among them, represents the sliding mode control surface, is the weight coefficient, represents the position error, represents the velocity error; At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero; The deviation is expressed as, Among them, represents the deviation of the sliding mode control surface, represents the time derivative of the weight coefficient, and are respectively the time derivatives of the speed error and the position error; If , it indicates that the linear motor has been operating stably along the sliding mode control surface and the state has approached the target state; if , continue to adjust the control input to make the state of the linear motor converge along the sliding mode control surface; Based on the deviation on the sliding mode control surface, a control input is generated through the sliding mode control algorithm ;​ The control input is expressed as, Among them, is the control gain of the deviation of the sliding mode control surface, representing the strength of the controller, is the sign function of the sliding mode control surface, is the control gain of the time derivative of the sliding mode control surface; According to the control input , the input current of the linear motor is adjusted in real time or the input voltage , expressed as Among them, and are the gain coefficients of voltage and current, representing the adjustment range of the input signal of the linear motor.

8. A multi-segment linear motor adaptive sliding mode speed control method according to claim 7, characterized in that: The speed interval switching mechanism includes, When the real-time speed of the linear motor crosses the interval boundary defined by the first speed threshold and the second speed threshold, trigger the switching mechanism; When the linear motor switches to a different speed interval, design a smooth transition mechanism. According to the speed interval switching, adjust the control gain based on the current speed error and position error of the linear motor.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the steps of a multi-segment linear motor adaptive sliding mode speed control method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of a multi-segment linear motor adaptive sliding mode speed control method according to any one of claims 1 to 8.

Images