Study of on-line backlash identification for PMSM servo system

Servo driver can greatly reduce the harm of backlash if it owns the function of identifying backlash automatically. Aiming at the problem of backlash identification in servo drive system, the automatic identification schemes on servo driver are reviewed. Based on the dead-zone model of backlash, five different identification methods are summed up. Each implementation process is analyzed specifically, mainly interpreting assumptions, hardware requirements and the problems that will be encountered in practice. The accuracy of theoretical analysis of various solutions is verified by simulation experiment. With the comparison of those simulation results, the speed difference integral method that needs few additional conditions and simple operations can obtain the accurate identification result just by a position sensor in servo motor side. So it is feasible strongly and is the best identification scheme, and the experimental result also proves it.