Measurement and analysis of backlash on harmonic drive

Abstract Harmonic drive transmissions are widely used in robotics, space manipulation systems because of their excellent mechanical properties including low backlash, high speed reduction ratio and compact size. Analytical investigation and modeling of backlash and hysteresis for harmonic drive are reported, but no thorough understanding of backlash as well as its attributes is available in literature. In this research, the experimental and analytical studies of backlash are conducted. First, the definition of backlash according to China National Standard (CNS) is given, which also matches the requirements in application. A dedicated apparatus was designed to measure the backlash. The results of this paper offer an insight into backlash of harmonic drive and the results are valuable in the mechanical design of harmonic drive gears as well as the dynamic modeling and precision control of harmonic drive systems.