High Precision Positioning Control System for a Nano Micro Manipulators Platform

摘要

The paper presents a real time control system for high precision positioning of a 4 nano micro manipulators platform in order to increase the positioning precision at high speed through reducing and compensating dynamic vibrations induced by the system's movement. The control system, based on the system dynamic inversion method, ensures a desired trajectory with a fast mitigation of the vibrations by introducing an active damping force computation, having as input signals velocity, position and in some cases force. Through determining the optimal trajectory, using a quadratic cost function for reducing tracking errors, there results a six fold increase in tracking speed on micro or nano-metric positioning precision. The robot control system with compliant wrist allows for the control of the hybrid position and force in Cartezian coordinates through real time processing of the Jacobine matrix obtained out of the forward kinematics using the Denevit-Hartenberg method and calculating the Jacobine inverted matrix for control in closed loop. Also, a new method for determining the control error is proposed consisting of a fuzzy multi-stage control on three different decision stages in order to determine the movement velocity. That implies the realization of three fuzzy control loops: one in position, one in force and the other in structural vibrations. The control systems allows for practically eliminating jamming and vibrations, having a fast response of the control loop. Finally, the system's performance will allow the introduction of new functions without significant change to the hardware and through an overwhelming contribution of knowledge in developing supplementary functions for a 4 nano-micro manipulators platform: nano-metric positioning, reducing structural vibrations, with direct application in nano-micro manufacturing.