Finite-Time Dynamic Tracking Control of Parallel Robots with Uncertainties and Input Saturation

Area of Science:

• Robotics
• Control Systems Engineering
• Mechatronics

Background:

• Parallel robots face challenges with dynamic tracking control due to uncertainties and input saturation.
• Existing control methods often struggle to achieve finite-time convergence and robustness.

Purpose of the Study:

• To develop a finite-time nonsingular terminal sliding mode control (FS-NTSMC) scheme for parallel robots.
• To enhance tracking performance, accuracy, and robustness in the presence of uncertainties and input saturation.
• To mitigate the chattering phenomenon common in sliding mode control.

Main Methods:

• A disturbance observer (DO) estimates lumped disturbances in the robot's dynamic model.
• A novel finite-time convergent auxiliary system compensates for input saturation using fractional exponential powers.
• The proposed FS-NTSMC integrates disturbance estimation and auxiliary system states for improved control.

Main Results:

• The control scheme achieves finite-time convergence and improves control accuracy and robustness.
• Disturbance estimation and compensation effectively reduce the control gain, alleviating chattering.
• Finite-time stability of the closed-loop system is rigorously proven using Lyapunov theory.

Conclusions:

• The proposed finite-time control strategy is effective for parallel robots with uncertainties and input saturation.
• The method offers superior performance compared to conventional approaches, demonstrated through simulations and experiments.
• This work contributes to advancing precise and reliable control for parallel robotic systems.