Continuous sliding mode disturbance rejection control for flexible joint robots with input saturation.

Area of Science:

• Robotics
• Control Systems Engineering
• Mechatronics

Background:

• Flexible joint robots (FJRs) face challenges from multi-source disturbances and input saturation.
• Accurate trajectory tracking is crucial for FJR performance in dynamic environments.
• Existing control methods struggle with unknown time-varying disturbances and actuator constraints.

Purpose of the Study:

• To propose a robust disturbance rejection control scheme for FJRs.
• To address both matched and mismatched disturbances and input saturation.
• To enhance trajectory tracking accuracy and system stability.

Main Methods:

• Utilizing the flatness method to transform mismatched disturbances into matched ones.
• Employing a generalized proportional integral observer (GPIO) for state and disturbance estimation.
• Designing an anti-windup compensation system for input saturation.
• Implementing an output feedback control framework based on continuous sliding mode control (CSMC).

Main Results:

• Achieved asymptotic convergence of the tracking error.
• Mitigated the chattering effect common in traditional sliding mode control (SMC).
• Demonstrated enhanced control and dynamic performance under input constraints.
• Validated stability of the closed-loop system.

Conclusions:

• The proposed CSMC-based control approach effectively handles disturbances and input saturation in FJRs.
• The method enhances trajectory tracking performance and system robustness.
• The approach offers a viable alternative to traditional disturbance rejection techniques.