A novel block backstepping-based trajectory tracking control with zero dynamics stability for underactuated overhead...

Area of Science:

• Robotics and Control Systems
• Mechanical Engineering

Background:

• Underactuated overhead cranes present significant control challenges due to unactuated load swing.
• Existing anti-swing control methods have limitations, and backstepping control has not been previously applied to these systems.

Purpose of the Study:

• To propose the first block backstepping-based trajectory tracking control scheme for 2-DOF overhead cranes.
• To achieve effective load swing suppression and improve both transient and steady-state performance.

Main Methods:

• A novel variable transformation with a state coupling function was designed for swing suppression.
• An integral state was incorporated into the Lyapunov candidate function to enhance steady-state performance.
• A trajectory tracking controller was developed using backstepping, with a new parameter tuning method utilizing pole placement.

Main Results:

• The proposed scheme rigorously proved stable using zero dynamics analysis and Lyapunov stability theorems.
• Experimental results demonstrated a trolley settling time of approximately 5 seconds and a steady-state error within 0.5%.
• The load swing angle was effectively controlled within [-0.5 deg, 0.5 deg] in about 4 seconds.

Conclusions:

• The block backstepping control scheme offers a robust and effective solution for trajectory tracking and anti-swing control in 2-DOF overhead cranes.
• The novel parameter tuning method simplifies control parameter adjustment.
• The proposed method outperforms existing techniques in terms of performance and robustness.