Approximation-Free Tracking Error Constraint Control for Lagrangian Systems.

This paper proposes an approximation-free adaptive tracking error constraint control scheme for unknown Lagrangian systems. A transformed filtered tracking error surface has been constructed to guarantee the transient and steady-state performance of the position control of the Lagrangian systems combined with adaptive estimation laws for unknown upper bounds of the parameters of the Lagrangian systems. To obtain fast error convergence, a finite-time control has been adopted in the proposed controller. In addition, the proposed controller is effective for the constrained positioning of Lagrangian mechanical systems with unknown deadzone input nonlinearity, without requiring nonlinear approximations or identification processes for unknown parameters of dynamics and deadzone. The effectiveness of the proposed constraint control scheme has been proven by simulation and experimental evaluations for an XY table and an articulated manipulator system in the presence of unknown deadzone. [ABSTRACT FROM AUTHOR]