MODELING AND OBSERVER-BASED ROBUST TRACKING CONTROL OF A NANO/MICRO-MANIPULATOR FOR NANOFIBER GRASPING APPLICATIONS

摘要

This paper presents the modeling and control of a nano/micro-manipulator for use in nano-fiber grasping and nano-fabric production. The RRP (Revolute-Revolute-Prismatic) manipulator considered here utilizes two rotational motors with 10~(-7) rad resolution and one linear Nanomotor~Re with 0.25nm resolution. Weighing just 30g and having short lever arms ( ＜ 5cm), the manipulator is capable of achieving well-behaved kinematic characteristics without backlash and with atomic scale precision to guarantee accurate manipulation at nanoscale. A mathematical model of the micromanipulator is formulated and both direct and inverse kinematics of the system as well as dynamic equations are presented. Several controllers for manipulator positioning tracking are derived and analyzed extensively. Unlike typical macroscale manipulator models and controllers, the controller development is not trivial due to nanoscale movement and forces, coupled with unmodeled dynamics and nonlinear structural dynamics. Following the development of the controllers, numerical simulations of the proposed controllers on the manipulator are used to verify the tracking performance.