Safe controller design for circular motion of a bicycle robot using control Lyapunov function and control barrier...

Area of Science:

• Robotics and Control Systems
• Autonomous Vehicle Dynamics

Background:

• Bicycle robots without trail or mechanical regulators present unique safety control challenges, especially during circular motion.
• Ensuring stability and safety under inevitable bounded input disturbances is critical for practical robot applications.

Purpose of the Study:

• To investigate and solve the safety control problem for a front-wheel-drive bicycle robot executing circular motion.
• To propose constraints on drive angular speed essential for achieving stable circular trajectories.

Main Methods:

• Development of a safe controller integrating control Lyapunov function (CLF) for input-to-state stability (ISS) and control barrier function (CBF) for input-to-state safety (ISSf).
• Implementation of the integrated CLF-CBF controller using quadratic programming (QP) to manage control effort and enhance safety.
• Validation through comparative simulations and physical experiments on a real bicycle robot.

Main Results:

• The proposed CLF-CBF-QP controller demonstrated enhanced safety performance in simulations compared to existing methods.
• The controller effectively reduced control effort while maintaining stability during circular motion.
• Physical experiments confirmed the controller's ability to achieve stable circular motion and validated its effectiveness.

Conclusions:

• The integrated ISS-CLF-ISSf-CBF-QP controller provides a robust solution for the safety control of bicycle robots in circular motion.
• This approach effectively balances safety, stability, and control efficiency in the presence of input disturbances.
• The findings pave the way for safer and more reliable autonomous robotic systems with similar dynamics.