Fixed-Time Tracking Control for Flexible Joint Manipulator With Prescribed Performance Constraint

Abstract

This paper studies the transient and steady performance constraints on flexible joint manipulator system with exogenous disturbance, and proposes a fixed-time prescribe performance tracking control method based on the singular perturbation model. For the fast subsystem, a subcontroller with superior transient performance is proposed that guarantees the suppression of flexible vibration in fixed-time. The remaining slow subsystem can be linked with rigid methods to achieve output constraints, a type of time-varying error constraint boundary is first constructed, which broadens the initial error constraint boundary of the time-varying tangent barrier Lyapunov function. Then, a slow subcontroller based on a non-singular fast-integration terminal sliding mode is constructed to make any initial tracking error converge in fixed-time. Finally, a nonlinear disturbance observer is used to counteract the exogenous disturbance. The simulation results show that the controller achieves the prescribe performance.

Keywords

• Flexible joint manipulator
• singular perturbation
• barrier Lyapunov function
• fixed-time
• prescribe performance