An adaptive sliding mode speed control method for multi-stage linear motor

Abstract

The present invention relates to the field of linear motor control technology and discloses a multi-stage linear motor adaptive sliding mode speed control method. The method constructs a linear motor's dynamic equation based on the linear motor's operating parameters; based on the dynamic equation, the linear motor's operating speed is divided into a low-speed range, a medium-speed range, and a high-speed range; and a speed range switching mechanism is designed. When the linear motor speed range switches, the control parameters are calculated and adjusted based on the linear motor's operating parameters to achieve a smooth transition of the control strategy. Through the design of an optimized sliding mode control surface, the present invention achieves precise regulation of the linear motor's input signal, ensuring that the linear motor can quickly stabilize to the target speed when operating at high speed, while maintaining accuracy in the low-speed and medium-speed ranges.

Description

Technical Field

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

[0002] In the field of linear motor control, especially linear motor control, with the increasing requirements for industrial automation and precision control, how to accurately regulate 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 used in linear motor control. However, these control methods often suffer from slow response, overshoot, and instability when faced with different load conditions, speed changes, and external disturbances. Especially when the linear motor speed or load changes significantly, traditional control methods may not be able to effectively ensure the stable and rapid response of the linear motor within each speed range.

[0003] Linear motors, operating based on the principle of electromagnetic induction, are characterized by linear motion and are commonly used for precision position control. Traditional control strategies, when applied to linear motors, often face challenges such as accumulated velocity and position errors, insufficient response speed, and poor stability. To meet the demands for higher precision and dynamic response, improving control algorithms has become a key research direction in this field.

[0004] Currently, control strategies based on sliding mode control (SMC) demonstrate strong robustness in dynamic systems, effectively addressing parameter uncertainty and external disturbances within the system. By designing an appropriate control surface, sliding mode control enables the system to operate stably within that surface, achieving precise control. However, in practical applications, particularly in linear motor speed control, sliding mode control still faces challenges in control surface design, range switching, and gain adjustment. In particular, the control strategy required for switching between different speed ranges of a linear motor requires greater refinement and precision. Summary of the Invention

[0005] The object 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 technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a multi-segment linear motor adaptive sliding mode speed control method, the method comprising:

[0007] Constructing the dynamic equations of the linear motor based on its operating parameters, where the operating parameters include current, speed, position, friction, rotational inertia, back electromotive force, mass, driving force, voltage, inductance, and resistance;

[0008] Based on the dynamic equation, the operating speed of the linear motor is divided into low speed range, medium speed range and high speed range;

[0009] In 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;

[0010] In 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 in the medium speed range;

[0011] In the high-speed range, a sliding mode control surface is designed. The deviation on the sliding mode control surface is used to calculate the control input, and the amplitude of the linear motor input signal is adjusted to make the linear motor state approach zero along the sliding mode control surface.

[0012] A speed range switching mechanism is designed. When the linear motor speed range is switched, 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.

[0013] Preferably, the construction of the dynamic equation of the linear motor includes:

[0014] By analyzing the relationship between the driving force and friction of the linear motor, describing the relationship between the acceleration of the linear motor and the state of the linear motor, the kinematic equation of the linear motor is derived;

[0015] The electrical equations of the linear motor are derived by describing the relationship between current and voltage using Kirchhoff's voltage law in combination with the operating parameters.

[0016] The kinematic equations of the linear motor are combined with the electrical equations to derive the dynamic equations of the linear motor.

[0017] Preferably, the dynamic equation of the linear motor is expressed as:

[0018]

[0019] in, Indicates the input voltage, represents the back electromotive force, represents the current, inductance, Represents resistance, represents acceleration, represents the rotational inertia of the linear motor, represents the linear motor constant, Represents friction.

[0020] Preferably, the dividing the running speed of the linear motor into a low speed interval, a medium speed interval and a high speed interval includes:

[0021] Calculate the acceleration of a linear motor based on the dynamic equation , integrate the acceleration to get the speed of the linear motor ;

[0022] 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;

[0023] When the speed of the linear motor When the speed 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;

[0024] When the speed of the linear motor When the speed is greater than the set second speed threshold, it is determined that the linear motor is in the high-speed range.

[0025] Preferably, the control parameters of the low-speed range are adjusted, and the input signal is the control input of the linear motor, including:

[0026] Based on the real-time collected operating parameters, the speed error and position error of the linear motor in the low-speed range are calculated. The speed error is the difference between the target speed and the actual measured speed, and the position error is the difference between the target position and the actual measured position.

[0027] Input the speed error and position error into the PID controller to calculate the control signal;

[0028] The PID controller calculates the output of the proportional part, the integral part, and the differential part. The proportional part adjusts the control signal according to the size 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.

[0029] The amplitude and direction of the linear motor input signal are adjusted by the adjustment amount output by the PID controller.

[0030] Preferably, the control parameters for adjusting the medium speed range include:

[0031] Calculate the speed error and position error of the linear motor in the medium speed range based on the real-time collected operating parameters;

[0032] The calculated speed error and position error are converted into fuzzy language through the adaptive control algorithm to generate fuzzy control rules and adjust the input signal amplitude of the linear motor.

[0033] Preferably, the adjusting the amplitude of the linear motor input signal includes:

[0034] Determine the velocity error and position error of the linear motor and define the sliding mode control surface;

[0035] The sliding mode control surface is expressed as,

[0036]

[0037] in, represents the sliding mode control surface, is the weight coefficient, represents the position error, Indicates speed error;

[0038] At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero;

[0039] The deviation is expressed as,

[0040]

[0041] in, represents the deviation of the sliding mode control surface, represents the time derivative of the weight coefficient, and are the time derivatives of velocity error and position error respectively;

[0042] like , indicating 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;

[0043] Through the sliding mode control algorithm, according to the deviation on the sliding mode control surface , generating control input ;

[0044] The control input is expressed as,

[0045]

[0046] in, is the control gain of the deviation of the sliding mode control surface, which represents 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;

[0047] According to the control input , real-time adjustment of the input current of the linear motor or input voltage , expressed as,

[0048]

[0049]

[0050] in, and is the gain coefficient of voltage and current, which represents the adjustment amplitude of the linear motor input signal.

[0051] Preferably, the speed range switching mechanism includes:

[0052] 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;

[0053] When the linear motor switches to different speed ranges, a smooth transition mechanism is designed to switch between speed ranges and adjust the control gain according to the current speed error and position error of the linear motor.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The control method of the present invention combines the advantages of sliding mode control and PID control to design a multi-stage speed control strategy. This method designs different control strategies for three different speed ranges: low, medium, and high, ensuring that the linear motor can operate stably and accurately within each speed range. In particular, the introduction of sliding mode control in the high-speed range significantly improves the robustness of the system, allowing the linear motor to quickly and accurately reach the target speed while avoiding the overshoot and oscillation that can occur with traditional PID control.

[0056] 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 the different working conditions of the linear motor. This control method based on real-time feedback from the linear motor can smoothly adjust the control strategy when the linear motor crosses the speed range, avoiding sudden changes in the control input when switching between ranges, and ensuring a smooth transition and stable operation of the system. Specifically, when transitioning 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; and when transitioning from high speed to medium speed or from medium speed to low speed, the reduction in gain can effectively suppress over-response and avoid system oscillation.

[0057] The present invention achieves precise regulation of the linear motor input signal through an optimized sliding mode control surface design, ensuring that the linear motor can quickly stabilize to the target speed during high-speed operation while maintaining accuracy in the low and medium speed ranges. This multi-stage control method enables smoother and more efficient operation of the linear motor, while also improving the system's adaptability and robustness to meet the needs of varying loads and operating conditions. Furthermore, the control method of the present invention, through a smooth range switching mechanism, provides an efficient and stable linear motor control solution without increasing complexity, addressing many shortcomings of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a step diagram of a multi-segment linear motor adaptive sliding mode speed control method described in the present invention. DETAILED DESCRIPTION

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0060] Example 1, with reference to Figure 1 , which is the first embodiment of the present invention, provides a multi-segment linear motor adaptive sliding mode speed control method, comprising:

[0061] Constructing the dynamic equations of the linear motor based on its operating parameters, where the operating parameters include current, speed, position, friction, rotational inertia, back electromotive force, mass, driving force, voltage, inductance, and resistance;

[0062] Based on the dynamic equation, the operating speed of the linear motor is divided into low speed range, medium speed range and high speed range;

[0063] In 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 linear motor input signal are adjusted, and the control parameters of the low-speed range are adjusted. The input signal is the control input of the linear motor, such as current or voltage, which determines the working state of the motor.

[0064] In 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 in the medium speed range;

[0065] In the high-speed range, a sliding mode control surface is designed. The deviation on the sliding mode control surface is used to calculate the control input, and the amplitude of the linear motor input signal is adjusted to make the linear motor state approach zero along the sliding mode control surface.

[0066] A speed range switching mechanism is designed. When the linear motor speed range is switched, 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.

[0067] The constructing of the dynamic equation of the linear motor includes analyzing the relationship between the driving force and 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;

[0068] The electrical equations of the linear motor are derived by describing the relationship between current and voltage using Kirchhoff's voltage law in combination with the operating parameters.

[0069] The kinematic equations of the linear motor are combined with the electrical equations to derive the dynamic equations of the linear motor.

[0070] The dynamic equation of the linear motor is expressed as,

[0071]

[0072] in, Indicates the input voltage, represents the back electromotive force, represents the current, inductance, represents resistance, represents acceleration, represents the rotational inertia of the linear motor, represents the linear motor constant, Represents friction.

[0073] The method of dividing the running 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. , integrate the acceleration to get the speed of the linear motor ;

[0074] 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;

[0075] When the speed of the linear motor When the speed 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;

[0076] When the speed of the linear motor When the speed is greater than the set second speed threshold, it is determined that the linear motor is in the high-speed range.

[0077] Adjusting the low-speed interval control parameters includes calculating a speed error and a position error of the linear motor in the low-speed interval based on the real-time collected operating parameters, wherein the speed error is the difference between the target speed and the actual measured speed, and the position error is the difference between the target position and the actual measured position;

[0078] Input the speed error and position error into the PID controller to calculate the control signal;

[0079] The PID controller calculates the output of the proportional part, the integral part, and the differential part. The proportional part adjusts the control signal according to the size 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.

[0080] The amplitude and direction of the linear motor input signal are adjusted by the adjustment amount output by the PID controller.

[0081] The adjusting of the medium speed range control parameters includes calculating the speed error and position error of the linear motor in the medium speed range based on the real-time collected operating parameters;

[0082] The calculated speed error and position error are converted into fuzzy language through the adaptive control algorithm to generate fuzzy control rules and adjust the input signal amplitude of the linear motor.

[0083] The adjusting the amplitude of the linear motor input signal includes determining the speed error and position error of the linear motor and defining a sliding mode control surface;

[0084] The sliding mode control surface is expressed as,

[0085]

[0086] in, is the weight coefficient, represents the position error, Indicates speed error;

[0087] At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero;

[0088] The deviation is expressed as,

[0089]

[0090] in, represents the deviation of the sliding mode control surface, represents the time derivative of the weight coefficient, and are the time derivatives of velocity error and position error respectively;

[0091] like , indicating 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;

[0092] Through the sliding mode control algorithm, according to the deviation on the sliding mode control surface , generating control input ;

[0093] The control input is expressed as,

[0094]

[0095] in, The control gain of the deviation of the sliding mode control surface represents 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;

[0096] According to the control input , real-time adjustment of the input current of the linear motor or input voltage , expressed as,

[0097]

[0098]

[0099] in, and is the gain coefficient of voltage and current, which represents the adjustment amplitude of the linear motor input signal.

[0100] The speed interval switching mechanism includes triggering the switching mechanism when the real-time speed of the linear motor crosses the interval boundary defined by the first speed threshold and the second speed threshold;

[0101] When the linear motor switches to different speed ranges, a smooth transition mechanism is designed to switch between speed ranges and adjust the control gain according to the current speed error and position error of the linear motor.

[0102] Determine key operating parameters of linear motors, including current ,speed ,Location , friction , rotational inertia , back electromotive force ,quality , driving force ,Voltage ,inductance and resistors These operating parameters are used to describe the dynamic behavior of the linear motor. In particular, speed and position are key state quantities of the linear motor, which directly affect the control strategy of the linear motor.

[0103] Derive the kinematic equations of the linear motor, taking into account the mass of the linear motor and rotational inertia , driven by the linear motor and friction The acceleration equation of the linear motor is derived from the relationship:

[0104]

[0105] in, is the acceleration, As driving force, is the friction 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 friction. Driving force Generated by current, through electromagnetic torque Interaction with the linear motor's rotational inertia and friction.

[0106] Derive the electrical equations for a linear motor, describing the current flow using Kirchhoff's Voltage Law (KVL) With voltage The relationship between:

[0107]

[0108] in, is the inductor, is the resistance, is the back electromotive force, represents the differential symbol, Indicates the rate of change of current over time, current As the input signal to the linear motor, it controls the output (speed, position) of the linear motor. This equation describes how the current changes with changes in voltage, back EMF, and resistance.

[0109] Combining electrical equations with kinematic equations, the complete dynamic equations of the linear motor are derived, including current The electromagnetic torque generated By linear motor constant The relationship with current is given by:

[0110]

[0111] in, is the linear motor constant, which expresses the relationship between the current and the generated electromagnetic torque. Acceleration of linear motor The following relationship exists:

[0112]

[0113] in, is the rotational inertia of the linear motor, is the acceleration, is the friction force. Substituting the expression into , we get:

[0114]

[0115] At this time, the current It can be derived from the electrical equations.

[0116] Combining the electrical equations with the mechanical equations to form a complete linear motor dynamics equation, by Substituting the expression into the mechanical equation, we get the complete linear motor control equation:

[0117]

[0118] in, is the input voltage, is the back EMF, 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.

[0119] When integrating, the existing technology usually considers the initial conditions to determine the constants. Assume that the linear motor is The initial velocity is , the existing integral formula is expressed as:

[0120]

[0121] in, is the integral variable, representing the change over time, is the initial speed of the linear motor, i.e. The speed of Indicates acceleration.

[0122] Therefore, the speed of a linear motor is the integral result of the acceleration changing with time, and the influence of the initial speed is taken into account.

[0123] The method of this embodiment transforms the linear motor dynamics equation, starting from the dynamics equation:

[0124]

[0125] This equation gives the acceleration, which can be further simplified to:

[0126]

[0127] Then, integrating both sides, we get the velocity :

[0128]

[0129] This formula clearly links the acceleration to the dynamic input of the linear motor (voltage, current, etc.), while the friction is also adjusted by the rotational inertia of the linear motor.

[0130] 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 relies directly on the integration of acceleration to obtain the speed, and then determines the working state of the linear motor based on the speed. However, this method faces multiple defects in practical applications. First, the traditional method usually ignores the nonlinear factors inside the linear motor, such as the impact of the linear motor's back electromotive force on the dynamic behavior of the system, resulting in a certain error between the solution result and the actual dynamic behavior. Secondly, the traditional method often accumulates errors during the integration of acceleration, especially when the linear motor load changes rapidly or the control input signal fluctuates greatly. The integral error will continue to 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, which cannot effectively adapt to the changes of the linear motor under different workloads and dynamic environments, resulting in a slow response speed in practical applications and the inability to adjust the control strategy in real time to cope with the dynamic changes of the linear motor.

[0131] This invention improves upon traditional methods by precisely modeling the dynamic behavior of linear motors and taking into account the interplay of multiple factors, such as current, input voltage, back electromotive force, and friction, to provide a more accurate formula for calculating linear motor acceleration. This formula not only calculates the linear motor's acceleration but also, in conjunction with the linear motor's control input, calculates the linear motor's speed in real time and determines the linear motor's operating state based on speed changes. Compared to traditional methods, this method avoids the inaccurate speed prediction caused by error accumulation and provides more precise linear motor control. Furthermore, the improved linear motor control method enables real-time updating of the speed range judgment criteria, dynamically adjusting the control strategy based on the linear motor's actual operating state (speed and acceleration). Through this real-time feedback mechanism, the linear motor's speed range can be adaptively divided in practical applications, thereby improving the response speed and accuracy of linear motor control.

[0132] In addition, the present invention further improves the robustness of the system by taking into account the nonlinear characteristics of the linear motor, especially the impact of changes in the back electromotive force of the linear motor on the operating state of the linear motor. In traditional methods, the back electromotive force of the linear motor is often not fully considered, and the impact of the back electromotive force on the behavior of the linear motor is particularly significant when the linear motor is at high speed. By adding the real-time changes in the back electromotive force of the linear motor to the dynamic model of the present invention, the behavior of the linear motor at high speed can be more accurately described, ensuring that the linear motor can maintain a stable operating state under rapid response. Furthermore, through the improvements of the present invention, the linear motor can adapt to fluctuations in voltage and current in different speed ranges, provide fine control, and avoid the instability and control errors caused by changes in back electromotive force in traditional methods.

[0133] It should be noted that the linear motor's operating parameters, including current, speed, position, back electromotive force, and friction, are collected in real time and fed back to the control system via sensors. Based on this real-time data, the linear motor's velocity error and position error are calculated. The velocity error is the difference between the target speed and the actual measured speed, and the position error is the difference between the target position and the actual measured position. These velocity and position errors are fed as inputs to a PID controller, which calculates the control signal. The PID controller generates outputs from the proportional, integral, and differential components. The proportional component adjusts the control signal based on the magnitude of the error, the integral component adjusts the output based on the accumulated error, and the differential component adjusts the output based on the rate of error change. The PID controller uses the adjustment value output to adjust the amplitude and direction of the linear motor's input signal in real time, gradually bringing the linear motor's speed and position closer to the target values. When the velocity error is large, the current amplitude is increased; when the velocity error is small, the current amplitude is reduced to avoid overacceleration. Based on the linear motor's response characteristics in the low-speed range, the PID controller's gain is adjusted in real time to adapt to the linear motor's dynamic changes, especially at low speeds where friction and inertia are high, ensuring smooth acceleration and reducing instability. By dynamically adjusting the parameters of the PID controller, the control process is optimized to ensure that the linear motor can start smoothly and accelerate gradually in the low-speed range.

[0134] Furthermore, in the low-speed range, the operating parameters of the linear motor are acquired in real time using current sensors, position encoders, speed sensors, back-electromotive force detectors, etc.

[0135] Calculate the speed error of the linear motor using the feedback signal collected in real time and position error The speed error is calculated by comparing the linear motor's target speed with the The actual measured speed The calculation formula is:

[0136]

[0137] Position error is obtained by comparing the target position The actual measurement position The calculation formula is:

[0138]

[0139] The control signal is calculated by the PID controller: the speed error and position error The input is fed into the PID controller, which uses the PID control algorithm to adjust the input signal. The controller calculates the output of each part based on the three parts of proportional, integral, and differential:

[0140] Proportional control: Calculate the proportional part of the control signal based on the size of the error.

[0141] Integral control: Based on the accumulation of errors, the output of the integral part is calculated to eliminate small errors that exist for a long time.

[0142] Differential control: According to the rate of error change, the output of the differential part is adjusted to prevent excessive response of the linear motor.

[0143] The amplitude and direction of the linear motor's input signal are adjusted in real time based on the adjustment value output by the PID controller. 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 reduced to avoid overacceleration or oscillation.

[0144] Because linear motors respond more slowly in the low-speed range and friction significantly impacts acceleration, dynamic adjustment of the PID controller's gains is necessary. By calculating the linear motor's acceleration, velocity variation, and error fluctuations in real time, the proportional, integral, and differential gains in the PID controller are dynamically adjusted to optimize control. This parameter adjustment ensures gradual acceleration of the linear motor, minimizing system instability and overshoot.

[0145] When the linear motor is affected by changes in load or friction in the low-speed range, the control system monitors feedback in real time and adjusts the control strategy to ensure smooth operation and avoid system oscillation. The control system adjusts the PID control gain based on the changes in the linear motor's state, especially during the low-speed start-up phase, gradually improving the system's response speed.

[0146] 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.

[0147] Based on the collected feedback signals, the linear motor's velocity error and position error are calculated in the medium-speed range. Unlike the PID control used in the low-speed range, an adaptive control algorithm is employed in the medium-speed range. This adaptive control algorithm dynamically adjusts control parameters based on the linear motor's current error value, acceleration, and operating status. The adaptive control algorithm automatically adjusts control gains based on real-time updates of the error and system dynamics, optimizing the linear motor's response characteristics and ensuring stable operation in the medium-speed range.

[0148] The error signal input to the adaptive control algorithm undergoes fuzzification or a dynamic gain adjustment process to calculate the control signal adjustment amplitude in real time. Adaptive control ensures that the linear motor adjusts the input signal amplitude to varying loads and dynamic disturbances by self-adjusting the control gain. This process adjusts the linear motor's acceleration state by varying the input current, ensuring that the linear motor consistently approaches and maintains the target speed within the target range.

[0149] Based on the linear motor's response characteristics, the control system further adjusts the direction and amplitude of the linear motor's input signal to achieve a smooth transition to the target speed. This avoids instability caused by excessive control in the low-speed range and reduces overshoot or oscillation associated with traditional PID control. The adaptive control algorithm effectively responds to changes in load and friction, optimizing the linear motor's control process in the medium-speed range and maintaining efficient operation.

[0150] It should be noted that when a linear motor operates in the medium-speed range, its speed has already reached a certain level, and the system's dynamic response becomes relatively stable. Because the linear motor's acceleration is relatively stable at this point, the impact of friction and load changes on the system is relatively reduced. Traditional PID control may cause overshoot or slow response. However, the introduction of an adaptive control algorithm enables the control system to dynamically adjust the control gain based on the linear motor's operating status and error changes, and to adapt to the linear motor's response characteristics in real time.

[0151] Using adaptive control algorithms, linear motor control systems can precisely regulate the linear motor's speed and position errors, dynamically adjusting control gains to optimize the linear motor's acceleration and deceleration. Compared to PID control, adaptive control avoids overshoot during response, thereby improving the linear motor's smoothness and accuracy.

[0152] In the medium-speed range, linear motors respond more smoothly and exhibit smaller errors. Therefore, precise control of the linear motor's input signal is essential to avoid system overshoot and unnecessary error accumulation. Adaptive control algorithms optimize the system's control of the linear motor by calculating errors and adjusting gains in real time. This allows the controller to automatically adjust gains based on the linear motor's current state (e.g., error magnitude and rate of change), making the linear motor control system more flexible and adaptable.

[0153] By dynamically adjusting gains, adaptive control effectively avoids over-response and avoids the oscillation and instability that can occur with traditional PID control in the medium speed range. The linear motor can smoothly transition to the target speed and maintain stable operation.

[0154] In its technical implementation in the medium-speed range, the adaptive control algorithm not only adjusts the amplitude and direction of the control signal based on the error calculation results, but also ensures smooth and precise changes in the input signal through gain adjustment. Especially under varying loads and fluctuating friction, the adaptive control algorithm provides precise regulation to ensure linear motor stability and prevent control instability caused by load fluctuations.

[0155] When a linear motor is subject to load changes or external disturbances, adaptive control can promptly adjust the amplitude and direction of the input signal, allowing the linear motor to be accurately controlled within the medium speed range. This precise error adjustment significantly improves the stability and operating efficiency of the linear motor and reduces the nonlinear instability issues that can arise from traditional control methods.

[0156] In the medium speed range, traditional PID control methods can lead to error accumulation and oscillation, especially when the control gain is too high. However, the adaptive control algorithm adjusts control parameters in real time based on the dynamic characteristics of the linear motor's operation, preventing excessive error accumulation. As the system's stability improves, the input signal becomes smoother, ensuring stable operation of the linear motor.

[0157] One of the most significant technical benefits of adaptive control in the medium-speed range is the suppression of error accumulation and oscillation. By adjusting gains in real time and optimizing input signal adjustments, linear motors can reduce error accumulation and maintain smooth and stable system operation. Traditional PID control methods are unable to effectively handle these dynamic changes.

[0158] In the medium speed range, sensors (such as current sensors, position encoders, speed sensors, and back-EMF measuring instruments) are used to collect real-time operating parameter data of the linear motor. These parameters are input into the control system in real time through the data acquisition module for subsequent feedback calculations.

[0159] The actual speed of the linear motor acquired in real time is compared with the target speed to calculate the speed error; similarly, the position error is calculated by comparing the actual position of the linear motor with the set target position. The error value is input into the adaptive control algorithm as a feedback signal for subsequent processing.

[0160] The calculated speed error and position error Input to the adaptive control algorithm. The adaptive control algorithm performs two main operations in this process:

[0161] The calculated speed error and position error are converted into fuzzy language to generate fuzzy control rules (for example, "large error" corresponds to "increase current", and small error corresponds to "reduce current").

[0162] The control gain is dynamically adjusted according to the actual operating status 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.

[0163] The adaptive control algorithm calculates and outputs control gains to adjust the linear motor's input signal. Gains are adjusted based on the linear motor's dynamic characteristics, taking into account factors such as friction, load, and the linear motor's rotational inertia in the medium speed range.

[0164] Dynamic gain adjustment: When the linear motor's operating state changes (such as load changes, friction fluctuations, etc.), the adaptive control algorithm adjusts the control gain based on real-time feedback information to keep the linear motor running stably within the target speed range.

[0165] According to the optimized control gain and error feedback, adjust the input signal amplitude of the linear motor (such as current or voltage ), to ensure that the linear motor can run smoothly in the target speed range.

[0166] The control system will gradually adjust the input signal of the linear motor according to the size and change trend of the current error to avoid excessive acceleration or deceleration, ensuring that the linear motor accelerates smoothly and approaches the target speed.

[0167] The control strategy is dynamically updated based on the linear motor's response characteristics within the medium-speed range. The control system continuously adjusts control parameters (such as proportional gain, integral time, and derivative time) and optimizes the control strategy in real time based on the linear motor's current state and load changes.

[0168] For larger errors, the control system accelerates the linear motor by increasing the current; when the error decreases, the system reduces the current to avoid over-acceleration and ensure system stability.

[0169] The control system continuously monitors the linear motor's operating status and adjusts control parameters through a feedback mechanism. The linear motor's control parameters (including current amplitude, gain, etc.) are optimized throughout the medium-speed range based on the motor's operating status, ensuring stable operation under varying loads and dynamic conditions.

[0170] In the medium-speed range, the linear motor control system uses an adaptive control algorithm to automatically adjust the control gain and optimize the linear motor's operation based on real-time feedback error values ​​and the linear motor's dynamic response characteristics. This control method dynamically adjusts the amplitude of the input signal according to the linear motor's actual operating state, ensuring that the linear motor can maintain the target speed within the medium-speed range. The adaptive control algorithm automatically adjusts control parameters when the load changes or the friction force fluctuates, allowing the linear motor to smoothly follow the set speed and effectively adapt to system changes.

[0171] Furthermore, the adaptive control algorithm calculates velocity and position errors in real time and adjusts the direction and amplitude of the input signal, avoiding the overshoot and oscillation that can occur with traditional PID control. During the linear motor's response, the control system optimizes the control signal based on the motor's acceleration and speed changes, reducing error accumulation and improving system robustness, thereby enhancing the linear motor's precise control capabilities within the medium-speed range.

[0172] In the high-speed range, a sliding mode control surface is designed based on the linear motor's speed and position errors. This surface forms a state surface by combining the linear motor's speed and position errors, and calculates the deviation between the error value and the sliding mode control surface.

[0173] The calculated error deviation is used as input to generate a sliding mode control surface deviation, which is then used to adjust the linear motor's input signal. The sliding mode control algorithm adjusts the linear motor's current or voltage based on the deviation to ensure that the linear motor's state approaches zero along the sliding mode control surface.

[0174] The core of sliding mode control surface design is to control the error toward zero, ensuring stable operation of the linear motor in the high-speed range. By adjusting the amplitude of the linear motor's input signal, oscillation and error at high speeds are reduced, allowing the system to converge quickly and stably when the linear motor reaches the set target speed.

[0175] 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, ensuring that the linear motor accurately maintains within the target speed range and can effectively resist external disturbances and load fluctuations.

[0176] Through the sliding mode control algorithm, the error value and sliding mode control surface deviation are calculated in real time, the control strategy of the linear motor is optimized, and the response speed and system stability of the linear motor in the high-speed range are further improved.

[0177] In the high-speed range, the speed error and position error of the linear motor are first calculated. The error describes the deviation between the actual speed and target speed, and the actual position and target position of the linear motor.

[0178] Based on the velocity error and position error, define the sliding mode control surface , usually expressed as:

[0179]

[0180] in, is the weight coefficient, which is used to adjust the relative influence of position error and velocity error on the sliding mode control surface to ensure that the control strategy is adjusted according to the dynamic characteristics of the linear motor.

[0181] At each moment, calculate the deviation on the current sliding mode control surface and check whether the deviation is zero:

[0182] Calculate sliding mode control surface The time derivative of , that is, the deviation on the sliding mode control surface:

[0183]

[0184] in, and are the time derivatives of the velocity error and position error, respectively, indicating the rate of change of the linear motor velocity and position.

[0185] 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 , then continue to adjust the control input to make the linear motor state converge along the sliding mode control surface.

[0186] Through the sliding mode control algorithm, according to the deviation on the sliding mode control surface , generating control input The control input is designed by the following formula:

[0187]

[0188] in, The control gain of the sliding mode control surface deviation represents the strength of the controller, is the sliding mode control surface sign function, is the control gain of the time derivative of the sliding mode control surface.

[0189] 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, and vice versa, the control input decreases.

[0190] According to the control input , real-time adjustment of the input current of the linear motor or input voltage The specific associations are:

[0191]

[0192] or:

[0193]

[0194] in, and is the gain coefficient of voltage and current, which represents the adjustment amplitude of the linear motor input signal.

[0195] Current control is suitable for situations where precise control of the linear motor torque is required, especially when the load changes greatly. Current control can quickly respond and adjust the linear motor torque.

[0196] Voltage control is suitable for situations where the linear motor speed needs to be precisely controlled, especially in the high-speed range. When the linear motor speed accuracy is required to be high, using voltage control can avoid overshoot caused by excessive current.

[0197] During the operation of the linear motor, the deviation on the sliding mode control surface is continuously calculated , and dynamically adjust the linear motor input signal according to the deviation to ensure that the linear motor state continues to approach zero along the sliding mode control surface, and finally make the linear motor run stably near the set target speed.

[0198] 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.

[0199] It should be noted that the weight coefficient λ is used to adjust the influence of position error and velocity error on the sliding mode control surface. This coefficient is typically determined by the linear motor's dynamic response characteristics, control accuracy requirements, and system stability. Generally, the weight coefficient λ is a positive constant that balances the relationship between position error and velocity error.

[0200] λ can be determined experimentally: First, set a preliminary weighting coefficient, conduct experiments, and observe the linear motor's response at different speeds. If the linear motor's response is too violent or oscillatory, reduce λ. If the linear motor has a delay in response or slows convergence, increase λ.

[0201] Theoretical deduction and optimal selection are performed based on the linear motor's mass, inertia, load change and other parameters.

[0202] The coefficient value can be adjusted according to the actual application scenario and optimized in combination with other parameters of the linear motor controller to obtain the best control effect.

[0203] Furthermore, in sliding mode control, the sign function By determining the direction of the control signal, the system can quickly approach the sliding mode control surface and maintain its stability. The specific implementation of the sign function is:

[0204]

[0205] The sign function calculates the direction of the linear motor control input, ensuring that the sign of the input signal aligns with the direction of the error. Based on the sign of the sliding mode control surface deviation, the control input generated by the sign function effectively guides the linear motor state toward zero, avoiding oscillation.

[0206] When the real-time speed of the linear motor crosses the boundary of the defined speed range, the range switching mechanism is triggered. The linear motor control system continuously monitors the speed of the linear motor, collects operating parameters such as current, speed, position, back electromotive force and friction in real time, and compares them with the set speed range. By comparing the current real-time speed of the linear motor with the threshold of the speed range, it is determined whether the linear motor has crossed the range boundary. If it has, the speed range switching mechanism is triggered to dynamically adjust the control gain. Based on the error values ​​of the linear motor, such as speed error and position error, the control system calculates the control gain adjustment amount, thereby adjusting the control input in real time to ensure that the linear motor smoothly transitions to the new speed range.

[0207] When the linear motor transitions from a low-speed range to a medium-speed range, the control gains are adjusted to accommodate the linear motor's acceleration needs. The proportional gain is increased to improve response speed, enabling the linear motor to quickly respond to changes in target speed. The integral gain is moderately increased to ensure the linear motor can eliminate long-term errors and smoothly transition to the medium-speed range. The differential gain is reduced to avoid overshoot or oscillation during the transition, maintaining system stability.

[0208] As the linear motor moves from the medium-speed range to the high-speed range, the PID controller's weight gradually decreases, and the sliding mode control algorithm's influence increases. The control system uses the sliding mode control algorithm to adjust the input signal amplitude and uses current as the primary control input to ensure that the linear motor reaches the target speed quickly and stably within the high-speed range. The sliding mode control surface precisely adjusts the linear motor's input based on changes in speed and position error, ensuring stability at high speeds.

[0209] As the linear motor decelerates from a medium speed range to a low speed range, the control gain is gradually reduced, and the proportional gain is decreased to prevent the linear motor from over-responding during deceleration. The integral and differential gains are then adjusted to optimize the linear motor's response requirements to prevent oscillation during deceleration. The differential gain is increased to help minimize error accumulation during deceleration and maintain the linear motor's stability.

[0210] If the linear motor jumps directly from a low speed range to a high speed range, a more significant control adjustment is required. In this case, the proportional gain needs to be significantly increased to accommodate the linear motor's acceleration. By increasing the influence of sliding mode control, the current or voltage control input quickly adjusts the linear motor's speed, ensuring stable operation within the high-speed range.

[0211] When a linear motor drops directly from a high-speed range to a low-speed range, the system must quickly reduce the input current or voltage, decrease the proportional gain, and increase the differential gain to enable the linear motor to decelerate smoothly and maintain stable operation in the low-speed range. Increasing the differential gain helps reduce oscillation or overshoot during deceleration, ensuring a smooth transition of the control signal.

[0212] During each speed range change, the control system dynamically calculates the control input and optimizes the gains based on the linear motor's real-time feedback, including velocity error, position error, and acceleration. This ensures a smooth transition to the target speed and avoids sudden changes and instability in the control input. Throughout this process, the control gains are adjusted using a smooth transition algorithm, ensuring efficient and stable operation within each speed range change.

[0213] In this technical solution, the speed range switching mechanism of the linear motor ensures a smooth transition between different speed ranges of the linear motor 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 to the high speed range, the gain adjustment enables the linear motor to respond quickly to the target speed and remain stable. By properly adjusting the proportional, integral and differential gains, overshoot, oscillation and instability are avoided, and the responsiveness of the system is enhanced. Conversely, when the linear motor switches from high speed to medium speed or from medium speed to low speed, reducing the proportional gain and increasing the differential gain further reduces the instability of the system, ensures a smooth deceleration process, and avoids excessive response of the linear motor.

[0214] This technical solution achieves precise control of the linear motor by dynamically adjusting the control input (current or voltage). The smooth transition of the control gain ensures that the linear motor does not experience drastic fluctuations or instability when switching speed ranges, thereby improving the robustness and adaptability of the control system. Especially when the linear motor directly transitions from low speed to high speed or high speed to low speed, the rapid gain adjustment ensures that the linear motor can quickly adapt to the new operating conditions, thereby maintaining precise and stable speed control.

[0215] It should be noted that, in this document, relational terms such as first and second, etc., are used only 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 terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0216] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0217] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A multi-stage linear motor adaptive sliding mode speed control method, characterized by: include, Constructing the dynamic equations of the linear motor based on its operating parameters, where the operating parameters include current, speed, position, friction, 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 low speed range, medium speed range and high speed range; In 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; In 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 in the medium speed range; In the high-speed range, a sliding mode control surface is designed. The deviation on the sliding mode control surface is used to calculate the control input, and the amplitude of the linear motor input signal is adjusted to make the linear motor state approach zero along the sliding mode control surface. Design a speed range switching mechanism. When the linear motor speed range switches, the control parameters are calculated and adjusted based on the linear motor's operating parameters to achieve a smooth transition of the control strategy. The control parameters of the low speed range are adjusted, and the input signal is the control input of the linear motor, including: Based on the real-time collected operating parameters, the speed error and position error of the linear motor in the low-speed range are calculated. The speed error is the difference between the target speed and the actual measured speed, and the position error is the difference between the target position and the actual measured position. Input the speed error and position error into the PID controller to calculate the control signal; The PID controller calculates the output of the proportional part, the integral part, and the differential part. The proportional part adjusts the control signal according to the size 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. The amplitude and direction of the linear motor input signal are adjusted by the adjustment amount output by the PID controller.

2. The method for adaptive sliding mode speed control of a multi-segment linear motor according to claim 1, wherein: The dynamic equations of the linear motor are constructed as follows: By analyzing the relationship between the driving force and friction of the linear motor, describing the relationship between the acceleration of the linear motor and the state of the linear motor, the kinematic equation of the linear motor is derived; The electrical equations of the linear motor are derived by describing the relationship between current and voltage using Kirchhoff's voltage law in combination with the operating parameters. The kinematic equations of the linear motor are combined with the electrical equations to derive the dynamic equations of the linear motor.

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

4. The method for adaptive sliding mode speed control of a multi-segment linear motor according to claim 3, wherein: The division of the linear motor's operating speed into a low-speed interval, a medium-speed interval, and a high-speed interval includes: Calculate the acceleration of a linear motor based on the dynamic equation , integrate the acceleration to get 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 When the speed 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 When the speed is greater than the set second speed threshold, it is determined that the linear motor is in the high-speed range.

5. The method for adaptive sliding mode speed control of a multi-segment linear motor according to claim 1, wherein: The control parameters for adjusting the medium speed range include: Calculate the speed error and position error of the linear motor in the medium speed range based on the real-time collected operating parameters; The calculated speed error and position error are converted into fuzzy language through the adaptive control algorithm to generate fuzzy control rules and adjust the input signal amplitude of the linear motor.

6. The method for adaptive sliding mode speed control of a multi-segment linear motor according to claim 1, wherein: In the high-speed range, a sliding mode control surface is designed, and the deviation on the sliding mode control surface is used to calculate the control input. The amplitude of the linear motor input signal is adjusted, including: Determine the velocity error and position error of the linear motor and define the sliding mode control surface; The sliding mode control surface is expressed as, in, represents the sliding mode control surface, is the weight coefficient, represents the position error, Indicates 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, in, represents the deviation of the sliding mode control surface, represents the time derivative of the weight coefficient, and are the time derivatives of velocity error and position error respectively; like , indicating 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; Through the sliding mode control algorithm, according to the deviation on the sliding mode control surface , generating control input ; The control input is expressed as, in, is the control gain of the deviation of the sliding mode control surface, which represents 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 , real-time adjustment of the input current of the linear motor or input voltage , expressed as, in, and is the gain coefficient of voltage and current, which represents the adjustment amplitude of the linear motor input signal.

7. The method for adaptive sliding mode speed control of a multi-segment linear motor according to claim 6, wherein: The speed range 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, the switching mechanism is triggered; When the linear motor switches to different speed ranges, a smooth transition mechanism is designed to switch between speed ranges and adjust the control gain according to the current speed error and position error of the linear motor.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the adaptive sliding mode speed control method for a multi-segment linear motor according to any one of claims 1 to 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a multi-segment linear motor adaptive sliding mode speed control method according to any one of claims 1 to 7 are implemented.

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