Effects of Backlash on the Walking Stability of Biped Robots

Abstract

Walking is an important ability for biped robots and its stability has attracted many researchers' attention. Backlash is an unavoidable factor that limits the performance of transmission and affects the walking stability. In this work, the dynamics simulation is used to analyze the effects of backlash on the walking stability of two biped robots with different designs of legs. The results show that the robot with the traditional series mechanism falls down when the amount of backlash is 0.6°, and the robot with the series-parallel mechanism falls down when the amount of backlash is 1.0°. The series-parallel mechanism results in the coupled movements between the knee and ankle joints. When the knee and ankle joints have the same direction of movement, the effect of backlash on the ankle joints is reduced by that on the knee joint. Therefore, the robot with the series-parallel mechanism has better walking stability than that with the traditional series mechanism under the effect of backlash.