Controller design for a Stewart platform using small workspace characteristics

Abstract

Configuration-dependent nonlinear coefficient matrices in the dynamic equation o f a robot manipulator impose computational burden in real-time implementation of tracking control based on the inverse dynamics controller. However, parallel manipulators such as a Stewart platform have relatively small workspace compared to serial manipulators. Based on the characteristics of small motion range, nonlinear coefficient matrices can be approximated to constant ones. The modeling errors caused by such approximation are compensated for by H-infinity controller that treats the error as disturbance. The proposed inverse dynamics controller with approximate dynamics combined with Hinfinity control shows good tracking performance even for fast tracking control in which computation of full dynamicsis not easy to implement.

Double Position Loop Design of AC Servo Drive System

“…Driven device adopts Japan Panasonic AC servo drives, which constitutes the input θ and the output θ angle servo system. External position closed loop motion control card as controller, it is composed of dual mode fuzzy controller, using grating displacement detection device, inductosyn line direct access to location information of workbench and ring angle servo system for driving device-driven workbench movement [4], precision of worktable displacements determined by linear displacement detection device. System block diagram is shown in Figure 3:…”