Position and force control of a pneumatic cylinder for Z axis actuator of a robot for assembly.

摘要

A pneumatic servo-system which is composed of a cylinder installed vertically, double electro-pneumatic proportional control valves and feedback equipments has been developed for a Z axis actuator of a robot for assembly. Optimal control method is applied to the system in order to accomplish accurate positioning and force control of the cylinder. Optimal control inputs for piston position and force have been computed by a microcomputer using optimal feedback coefficients which are derived from Riccati's equations so as to minimize settling time and overshoot of the step response in positioning and force control of the piston. In the piston control, the positioning repeatability of ±0.5 mm for the optimal control and ±0.2 mm for the optimal control with an integral compensator is achieved. On the other hand, the repeatability of within ±1% of an assigned force is obtained in the force control.