Control system design for a robotic autoloader

Control system design for a robot operating in a constrained work volume is addressed. The controllers must be designed so that the resultant trajectories do not violate these boundary constraints. Furthermore, the trajectories must be near minimum time and have minimum fluctuation to satisfy the spatial constraints, as well as minimum overshoot for endpoint accuracy. The most stringent requirements are that the controllers must be implementable using state of the art computer components and they must have adequate robustness to allow for robot parameter variations and disturbances. To meet these requirements one is restricted to somewhat classical controllers such as PID, nonlinear feedback laws with integrators and for certain tasks, minimum time strategies are applicable. Thus, the purpose of this paper is to investigate and compare these strategies subject to the above constraints.