Time-varying control of nonlinear systems with constraints and application to a wafer transfer robot

The real plant is generally expressed as time-varying nonlinear dynamic equation with several constraints. This paper deals with this nonlinear systems by dynamic inversion and LTV (linear time-varying) control theory using time-varying eigenvalue concept. Dynamic inversion methods can´t guarantee robustness with respect to disturbances and modeling uncertainties. So LTV control theory for error dynamics is used to solve this problem. In order to apply this control systems, command shaping filter to make admissible command trajectory is needed. We can get this trajectory by using TVB (time-varying bandwidth) filter. It makes us get admissible trajectory to be satisfied with constraints by adjusting the filter bandwidth. This paper applies this control systems to a wafer transfer robot with input and linear acceleration limits.