Safe Control of a 2DOF Helicopter Using Exponential Control Barrier Function
Keywords: Control Barrier Function, Safety, 2DOF Helicopter, Quadratic Programming, Optimal Control
AbstractThis work presents the safe control of a 2 degrees-of-freedom (2DOF) helicopter. We consider a control framework that unifies stability/tracking objectives, expressed as a nominal control law, and safety constraints, expressed as control barrier functions (CBFs), through a quadratic programming (QP) and the safety constraints must be prioritized. A linear quadratic regulator (LQR) is applied as the nominal control law and two safety constraints are considered to ensure that pitch and yaw angles never exceed predetermined bounds. As these safety constraints have high relative-degree, we represent them as exponential control barrier functions (ECBFs). The system model is based on a 2DOF helicopter available at EPUSP. The results obtained through numerical simulations demonstrate that the safety constraints are always satisfied and the tracking objectives are satisfied just when are not in conflict with the safety constraints.