A motor multi-loop cooperative control method and system for a tree climbing robot based on a sliding mode control

Abstract

The application relates to a motor multi-loop collaborative control method and system of a tree-climbing robot based on a sliding mode control, taking an STM32 as a control core to construct a speed loop and current loop collaborative control architecture. The system establishes a closed-loop control system taking PWM modulation as an execution layer, a current loop as an inner loop and a speed loop as an outer loop. The speed loop is constructed with a sliding mode surface and an approaching law based on encoder feedback speed to generate a target current instruction; the current loop adjusts the PWM duty cycle in real time according to a current error to realize accurate driving of the motor. In view of complex working conditions such as load change and slipping during tree climbing, a disturbance detection and robust compensation mechanism is designed, external disturbances are identified by monitoring speed mutation, the sliding mode gain and approaching law parameters are adaptively adjusted, and disturbance compensation is implemented, so that the dynamic response capability and anti-interference performance of the system are improved. The method realizes high-precision and high-robust control of the motor, and significantly improves the climbing stability and reliability of the tree-climbing robot.

Description

[0001] This invention relates to the field of robot control technology, and in particular to a multi-loop cooperative control method and system for motors of tree-climbing robots based on sliding mode control, which is suitable for stable and robust control of drive motors of tree-climbing robots in complex tree trunk environments. Background Technology

[0002] With the development of biomimetic robot technology, tree-climbing robots have broad application prospects in forestry inspection, ecological monitoring, power line inspection, and disaster relief. During the climbing process, tree-climbing robots need to face complex environmental factors such as rough tree trunks, varying diameters, unstable friction coefficients, and load variations. Therefore, this places high demands on the stability, response speed, and anti-interference capabilities of the drive motor control system.

[0003] Existing motor control methods for tree-climbing robots mostly employ traditional PID control strategies. While PID control is simple in structure, it is easily affected by external disturbances in complex environments, leading to problems such as overshoot, oscillation, and even instability. Furthermore, traditional control methods struggle to provide timely and effective compensation when the robot slips on the tree trunk surface or experiences sudden load changes.

[0004] Meanwhile, during actual climbing, the robot's drive system needs to respond quickly to speed changes and maintain stable operation, which traditional single-loop control structures cannot meet. Therefore, a multi-loop control structure needs to be constructed, using coordinated control of the speed loop and current loop to improve system stability.

[0005] Sliding mode control is a robust nonlinear control method that can effectively suppress system parameter uncertainties and external disturbances. However, when applying sliding mode control to the motor drive system of a tree-climbing robot, it is necessary to combine it with a multi-loop control structure and a disturbance detection mechanism to achieve a more stable and reliable control effect.

[0006] Therefore, it is of great significance to propose a multi-loop cooperative control method and system for the motors of a tree-climbing robot based on sliding mode control to improve the stability and anti-disturbance ability of the robot in complex tree trunk environments. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-loop cooperative control method and system for the motors of a tree-climbing robot based on sliding mode control, so as to solve the problems of insufficient anti-disturbance capability and low control accuracy of existing control methods.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A multi-loop collaborative control system for a tree-climbing robot motor based on sliding mode control includes an STM32 controller, a motor drive module, an encoder detection module, a current sampling module, and a PWM output module.

[0010] The STM32 controller is used to implement multi-loop control algorithms and sliding mode control algorithms, and to provide unified control over all modules.

[0011] The encoder detection module is used to collect motor speed information in real time and feed the collected data back to the STM32 controller.

[0012] The current sampling module is used to detect the motor operating current and feed the current signal back to the control system.

[0013] The PWM output module is used to generate PWM drive signals to control the operation of the motor driver.

[0014] In one embodiment, the control system employs a multi-loop control structure, including a speed control loop, a current control loop, and a PWM modulation loop.

[0015] In one embodiment, the PWM modulation loop serves as the innermost control loop and is used to generate the motor drive PWM signal.

[0016] In one embodiment, the current control loop serves as an intermediate control loop, used to adjust the motor current and achieve motor torque control.

[0017] In one embodiment, the speed control loop serves as an outer control loop for controlling the motor speed.

[0018] In one embodiment, the speed control loop employs a sliding mode control algorithm to improve the system's disturbance rejection capability.

[0019] In one embodiment, the system further includes a disturbance detection module for detecting sudden changes in motor speed.

[0020] In one embodiment, when a change in motor speed is detected to exceed a set threshold, the system determines it to be a sudden load change or slippage, and enhances the robustness of the control system by increasing the sliding mode control gain and adjusting the reaching law coefficient.

[0021] In one embodiment, once the system returns to stable operation, the control parameters automatically revert to normal sliding mode control parameters.

[0022] Compared with existing technologies, this invention has the following advantages: 1. This invention adopts a multi-loop control structure combining speed loop and current loop, improving the stability and response speed of the motor control system. 2. This invention introduces a sliding mode control algorithm into the speed control loop, which has stronger robustness compared to the traditional PID control method. 3. This invention, through disturbance detection and robust compensation mechanisms, enables the system to quickly recover stability when there are sudden load changes or robot slippage. 4. This invention is suitable for the drive control of tree-climbing robots in complex tree trunk environments, improving the stability and reliability of the robot during the climbing process. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the system initialization process for a multi-loop cooperative control method and system for motors of a tree-climbing robot based on sliding mode control.

[0024] Figure 2 A flowchart illustrating the multi-loop control architecture of a tree-climbing robot motor multi-loop cooperative control method and system based on sliding mode control is provided.

[0025] Figure 3 This is a schematic diagram illustrating the construction process of the sliding mode controller for a multi-loop cooperative control method and system for motors of a tree-climbing robot based on sliding mode control.

[0026] Figure 4 This is a schematic diagram of the main flow of real-time multi-loop collaborative control of a tree-climbing robot motor multi-loop collaborative control method and system based on sliding mode control.

[0027] Figure 5 This is a schematic diagram of the disturbance detection and robust compensation process of a multi-loop cooperative control method and system for motors of a tree-climbing robot based on sliding mode control. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] A multi-loop cooperative control method for motors of a tree-climbing robot based on sliding mode control is proposed. The control process includes steps such as system initialization, establishment of multi-loop control architecture, construction of sliding mode controller, and real-time control execution.

[0030] In one embodiment, the STM32 controller is connected to the encoder interface module, the current sampling module, and the PWM output module, respectively. The encoder interface module is used to collect motor speed information, the current sampling module is used to collect motor operating current information, and the PWM output module is used to generate PWM drive signals to drive the motor.

[0031] In one embodiment, the control system first executes a system initialization process. After the system is powered on, the STM32 controller first completes system clock initialization and basic hardware configuration. Then, it initializes the PWM output module to generate PWM signals for driving the motor; initializes the encoder interface module to acquire motor speed feedback signals; and initializes the current sampling module to acquire real-time motor current information.

[0032] After completing hardware initialization, the system loads motor and control parameters, including motor rated parameters, controller parameters, and control cycle parameters. It then sets the target motor speed and enters the main control loop, awaiting the execution of real-time control tasks.

[0033] In one embodiment, the present invention constructs a multi-loop control structure. The multi-loop control structure includes a speed control loop, a current control loop, and a PWM modulation loop. The PWM modulation loop, as the innermost control loop, is used to convert the control signal into a PWM duty cycle signal; the current control loop is used to adjust the motor current to achieve a fast dynamic response of the motor; and the speed control loop is used to achieve closed-loop control of the motor speed.

[0034] In one embodiment, the speed control loop outputs a current reference value and uses it as an input to the current control loop; the current control loop calculates a current control quantity based on the current error and outputs it to the PWM modulation loop; the PWM modulation loop generates a PWM duty cycle signal based on the control quantity, thereby driving the motor to run.

[0035] In one embodiment, the present invention introduces a sliding mode controller into the speed control loop. The system first inputs the target motor speed and simultaneously acquires the actual motor speed through an encoder module. Then, it calculates the error between the target speed and the actual speed and constructs a sliding surface function based on the error.

[0036] After constructing the sliding surface, a sliding mode convergence law is designed to make the system state converge toward the sliding surface. Then, the control output is calculated according to the sliding mode control law, and this output is used as the reference input of the current control loop, thereby achieving robust control of the motor speed.

[0037] During the system initialization phase, after the system is powered on, the STM32 controller is started first, and the system clock and peripherals are initialized.

[0038] Then, the PWM output module is initialized to generate the PWM signal required for motor drive.

[0039] Next, initialize the encoder interface module to collect motor speed data in real time.

[0040] At the same time, the current sampling module is initialized to collect the motor current feedback signal.

[0041] After completing hardware initialization, load the motor and controller parameters, and set the target motor speed.

[0042] During the multi-loop control architecture establishment phase, the system constructs a multi-loop control structure for the motor, including a PWM modulation loop, a current control loop, and a speed control loop.

[0043] The PWM modulation loop is located at the bottom layer of the control structure and is used to generate PWM drive signals.

[0044] The current control loop is used to adjust the motor drive current based on the current error.

[0045] The speed control loop, as the outermost control loop, has its output serving as the target current input for the current control loop.

[0046] A sliding mode control algorithm is introduced into the speed control loop. A sliding mode surface is constructed by calculating the error between the target speed and the actual speed, and a sliding mode reaching law is designed to achieve stable control of the motor speed.

[0047] During real-time control, the system first collects encoder data and calculates the current motor speed.

[0048] Then, the sliding mode speed controller is invoked to calculate the target current based on the speed error.

[0049] The system collects the motor current feedback signal and calculates the current error.

[0050] The current control algorithm is executed based on the current error, and the PWM duty cycle is calculated.

[0051] Finally, the PWM output signal is updated to drive the motor.

[0052] To improve the system's anti-interference capability, this invention also designs a disturbance detection and robust compensation mechanism.

[0053] The system monitors motor speed changes in real time. When a sudden change in speed is detected that exceeds the set threshold, it is determined to be a sudden change in load or robot slippage.

[0054] At this point, the system automatically increases the sliding mode control gain and improves the reaching law coefficient to enhance the robustness of the control system.

[0055] Once the system detects that the operating status has stabilized, the control parameters are restored to the normal sliding mode control parameters, and the normal control flow is returned.

[0056] The above embodiments are merely illustrative of several implementations of the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and all such modifications and improvements fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control, characterized in that, include: STM32 controller, motor drive module, encoder detection module, current sampling module, and PWM output module; The STM32 controller is used to execute the multi-loop collaborative control algorithm and the sliding mode control algorithm for the motor, and to perform unified control of each module; The encoder detection module is used to collect motor speed information in real time and feed back the collected motor speed to the STM32 controller; The current sampling module is used to detect the motor operating current and feed the current signal back to the STM32 controller. The PWM output module is used to generate PWM drive signals to control the motor drive module to drive the motor to run; The STM32 controller constructs a speed control loop and a current control loop based on the feedback information from the encoder detection module and the current sampling module. Stable motor operation is achieved through multi-loop collaborative control. The speed control loop uses a sliding mode control algorithm to control the motor speed.

2. The method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control as described in claim 1, characterized in that... The control system adopts a multi-loop control structure, including a speed control loop, a current control loop, and a PWM modulation loop, wherein the PWM modulation loop is the innermost control loop, the current control loop is the middle control loop, and the speed control loop is the outermost control loop.

3. The method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control according to claim 2, characterized in that, The speed control loop is used to generate a target current signal based on the error between the target speed and the actual speed of the motor, and input the target current signal to the current control loop.

4. The method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control according to claim 3, characterized in that, The current control loop is used to calculate the PWM control quantity based on the error between the target current and the actual current, and input the PWM control quantity to the PWM modulation loop to adjust the motor drive signal.

5. The method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control according to claim 1, characterized in that; The speed control loop adopts a sliding mode control algorithm, which constructs a sliding mode surface by calculating the speed error between the target speed and the actual speed, and calculates the control output according to the preset sliding mode reaching law.

6. The method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control according to claim 5, characterized in that, The sliding mode control algorithm includes a sliding surface construction step and a reaching law design step, wherein the sliding surface is composed of velocity error and its rate of change.

7. The method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control according to claim 1, characterized in that, The control system also includes a disturbance detection module for real-time detection of changes in motor speed.

8. A method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control, as described in claim 7, is characterized in that... When the disturbance detection module detects that the change in motor speed exceeds a preset threshold, the system determines that it is a sudden load change or robot slippage, and improves the anti-disturbance capability of the control system by increasing the sliding mode control gain.

9. A method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control, as described in claim 8, is characterized in that... After detecting that the motor's operating status has returned to stability, the system automatically restores the original sliding mode control parameters.

10. A method and system for multi-loop cooperative control of motors in a tree-climbing robot based on sliding mode control, as described in claim 1, is characterized in that... The STM32 controller is an STM32F4 series microcontroller, which generates PWM signals through a timer module to drive the motor.

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