STUDY ON POSITIONING ACCURACY OF RECIPROCATING FRICTION DRIVE SYSTEM

The positioning accuracy of the friction drive system was analyzed exp erimentally and theoretically in the reciprocating friction drive test er under the dry contact using the specimen of medium carbon steel S45 C. Effects of normal load, driver speed and spring constant on the pos itioning accuracy are investigated in this study. Results show that th e traction force calculated from the kinematic analysis under pure rol ling assumption agrees well with the experimental values. Based on the experimental results, the correlation formula of slip displacement in terms of the amplitude of traction force, driver speed and normal loa d is obtained for a wide range of operating parameters. To obtain a be tter positioning accuracy, the amplitude of traction force should be c lose to zero for both zones, S < 0 and S > 0. At very low spring const ant, higher normal load has a better positioning accuracy than lower n ormal load. However, at high spring constant, since the tangential for ce generated from the spring and higher normal load on the contact sur face would produce severe wear or peaks at two limit positions, lower normal load has better positioning accuracy than higher normal load.