Micro/Macro Dynamic Characteristics of Mechanism with a Harmonic Speed Reducer and Precision Rotational Positioning Control Using Disturbance Observer.

Abstract

This paper describes the dynamic characteristics and precision rotational positioning of the mechanism with a harmonic speed reducer. The harmonic speed reducer is the reduction gear that is often used for precision robots because they can be made very compact and lightweight without backlash. However they have the friction and the low stiffness which make the positioning performance low. The purpose of this research is to clarify the suitable control method for the rotational positioning mechanism with the reduction gear and to realize high speed and high precision rotational positioning over a wide range. For this purpose, first, the characteristics of the mechanism are examined experimentally. The experimental results show that the mechanism can be represented by two kinds of models, those are micro and macro dynamic models. Then, by using the controller including a disturbance observer, the mechanism has the positioning accuracy better than 1" on the working range more than 4.0×105"