Study on positioning accuracy of reciprocating friction drive system

The positioning accuracy of the friction drive system was analyzed experimentally and theoretically in the reciprocating friction drive tester under the dry contact using the specimen of medium carbon steel S45C. Effects of normal load, driver speed and spring constant on the positioning accuracy are investigated in this study. Results show that the traction force calculated from the kinematic analysis under pure rolling 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 load is obtained for a wide range of operating parameters. To obtain a better positioning accuracy, the amplitude of traction force should be close to zero for both zones, S < 0 and S > 0. At very low spring constant, higher normal load has a better positioning accuracy than lower normal load. However, at high spring constant, since the tangential force generated from the spring and higher normal load on the contact surface would produce severe wear or peaks at two limit positions, lower normal load has better positioning accuracy than higher normal load.