Design of a planar-type high speed parallel mechanism positioning platform with the capability of 180 degrees orientation

This paper presents a planar-type redundantly actuated parallel mechanism, for which the maximum velocity is 150 m/min with an acceleration of 2 g. The velocity is one of the highest for positioning platforms with the stroke around 500 mm. Since it has three degrees-of-freedom and four actuators, it has basically one redundancy that is essential to achieve high-degree dexterous motions. This paper deals with the theoretical results of kinematic and dynamic analysis of the mechanism, control issues for maintaining high velocity and positioning accuracy, redundancy control issue, and finally, the experimental results obtained from the prototype. (C) 2008 CIRP.