SENSOR-ACCURACY PRECISION POSITIONING WITH THE EXISTENCE OF STATIC FRICTION PART II - PARAMETER ESTIMATION OF STATIC FRICTION AND INTEGRAL CONTROL FOR PRACTICAL POSITIONING PROBLEMS

摘要

The main difficulty in a direct drive positioning system is to overcome the static friction and the induced nonlinear behavior between the contacting surfaces. Static friction is commonly modeled as a dead zone type nonlinear system. However, because of the uncertainty of the breakaway force and other factors, it is hard to achieve very high and persistent precision. In this research, it is shown that, with the new knowledge of the friction behavior during the pre-sliding range, it is possible to obtain persistent sensor-accuracy precision positioning using integral control. Besides the positioning problem, parameter estimation and simulation algorithms for static friction are also addressed in this part of the paper as a complement to part I of this paper.