End-Point Control of Fast and Precise Macro/Micro-Manipulators

Abstract

This paper presents a high performance macro/micro-manipulator architecture for rapid and precise positioning operations. The control approach si based on end-point position measurements in a limited range. Since the macro-manipulator can't be controlled precisely at high speed, due to structure and joint flexibility, the micro-manipulator is controlled to correct possible misalignments between the end-point relative to the target and also to compensate for the vibrations occurring at end-point, thus improving the accuracy and decreasing the cycle time. First the paper presents the design and the performance of the voice-coil micro-manipulator that we have developed. The system achieves an accuracy of 1µm and a settling time of 15 ms. Secondly, an end-point position control strategy for the macro/micro-manipulator that compensates for the oscillations measured at end-point is presented. In particular, the controller of the micro-manipulator accounts for the interaction with the macro-manipulator. Finally, experimental results demonstrating the efficiency of the method are presented.