Improved integral backstepping control of variable speed motion systems with application to a laboratory helicopter

Area of Science:

• Robotics and Control Systems
• Aerospace Engineering
• Nonlinear Control Theory

Background:

• The Two-Rotor Aero-dynamic System (TRAS) presents complex nonlinear dynamics and coupling effects, posing challenges for precise real-time control.
• Existing control methods often struggle with improving transient response and tracking accuracy, especially under external disturbances.
• Integral backstepping is a powerful technique for nonlinear systems, but its application to systems like TRAS requires enhancements.

Purpose of the Study:

• To develop an improved integral backstepping control strategy for the TRAS.
• To enhance the transient response and tracking performance for both constant and time-varying references.
• To validate the proposed method's robustness against system coupling and external disturbances.

Main Methods:

• Decomposition of the TRAS into horizontal (HS) and vertical (VS) subsystems.
• Augmentation of traditional backstepping with direct integral action for each subsystem.
• Modification of the dual boundary conditional integration method to improve transient response.
• Implementation of a switching technique to address jerking effects in the HS bi-directional motor.

Main Results:

• The proposed integral backstepping method significantly improved transient and tracking performance compared to prior conditional integration techniques.
• Experimental results confirmed enhanced performance for both constant and time-varying reference tracking.
• The control strategy demonstrated robustness against inherent system coupling and simulated wind gust disturbances.

Conclusions:

• The enhanced integral backstepping approach offers superior real-time control for the TRAS.
• The modified dual boundary conditional integration and switching technique effectively address system nonlinearities and disturbances.
• This method provides a robust and high-performance solution for controlling complex aerial robotic systems.