Input Shaping enhanced Active Disturbance Rejection Control for a twin rotor multi-input multi-output system (TRMS)

Area of Science:

• Robotics and Control Systems
• Mechanical Engineering
• Mechatronics

Background:

• Two-degree-of-freedom (2-DOF) systems like the Two-Link Robotic Manipulator System (TRMS) present challenges in trajectory tracking and disturbance rejection due to un-measurable states, modeling uncertainties, and unknown disturbance torques.
• Existing control strategies often require decoupling the system into subsystems, which can be complex and may neglect crucial coupling effects.

Purpose of the Study:

• To develop and validate a composite control strategy for a 2-DOF TRMS that achieves accurate trajectory tracking and robust disturbance rejection.
• To address system nonlinearities and complex coupling effects without explicit decoupling of the TRMS subsystems.

Main Methods:

• A composite control approach integrating Active Disturbance Rejection Control (ADRC) with feed-forward Input Shaping was designed for the 2-DOF TRMS.
• The controller derivation maintained the inherent coupling effects of the TRMS, avoiding the need for subsystem decoupling.
• The proposed control method was implemented on an experimental TRMS platform.

Main Results:

• Experimental validation demonstrated superior performance of the proposed composite ADRC and Input Shaping controller compared to traditional PID and standalone ADRC controllers.
• The controller achieved excellent set-point tracking behavior and effective disturbance rejection even under system nonlinearity and complex coupling conditions.
• The method proved effective in managing un-measurable states and uncertainties inherent in the TRMS.

Conclusions:

• The composite control strategy based on ADRC and Input Shaping offers a robust and effective solution for controlling 2-DOF TRMS.
• This approach successfully mitigates challenges posed by system nonlinearities, coupling effects, and external disturbances.
• The findings highlight the potential of this composite control for advanced robotic manipulator applications.