Position Control of Gear Shift based on Sliding Mode Active Disturbance Rejection Control for Small-Sized Tractors.

Area of Science:

• Agricultural Engineering
• Control Systems Engineering
• Robotics

Background:

• Small-sized tractors often suffer from prolonged gear shifting times and reduced quality due to imprecise motor control in automatic mechanical transmissions (AMTs).
• Existing control methods may not adequately address unmodeled dynamics and external disturbances affecting AMT actuators.
• Accurate and rapid positioning of the gear shift actuator is crucial for efficient tractor operation.

Purpose of the Study:

• To design a modified sliding mode active disturbance rejection control (MSMADRC) system for small-sized tractor AMT gear shift actuators.
• To enhance the position control precision and reduce the shift time of the AMT system.
• To improve the overall shifting quality in automatic mechanical transmissions.

Main Methods:

• Developed a control model for the motor incorporating total disturbance.
• Implemented an extended observer to monitor unmodeled dynamics and real-time disturbances.
• Designed a sliding mode surface within the active disturbance rejection control (ADRC) framework, integrating extended state and feedback variables for sliding mode control (SMC).
• Utilized Lyapunov theory to prove the stability of the developed control system.

Main Results:

• The MSMADRC system demonstrated a 37% higher position control precision compared to standard SMC.
• The MSMADRC system achieved a 75% higher position control precision compared to standard ADRC.
• The MSMADRC system exhibited the fastest response speed, completing the action in approximately 0.7 seconds.
• Simulation results confirmed the superior performance of MSMADRC in terms of precision and speed.

Conclusions:

• The proposed MSMADRC offers a significant improvement in position control for AMT gear shift actuators in small-sized tractors.
• This advanced control strategy effectively addresses issues of long shift times and poor shifting quality.
• MSMADRC provides a robust and efficient solution for enhancing tractor transmission performance.