Residual vibration suppression for series elastic actuator based on phase plane analysis and trajectory tracking

This paper proposes a residual vibration suppression method for a series elastic actuator (SEA). The method is made up of two parts: the trajectory planning for motor based on phase plane analysis (PPA) and trajectory tracking with a nonlinear disturbance observer. Though SEA provides some benefits, it suffers from extremely difficult position control issue, especially the residual vibration resulted from the elastic component between the actuator and payload. Therefore, an efficient method for this problem is proposed in this paper. Specifically, the variation law of the SEA in the phase plane is firstly derived via mathematically analysis, then a trapezoidal acceleration trajectory planning method for the motor side of SEA is used based on this analysis. Moreover, a trajectory tracking method with a disturbance observer (NDOB) is proposed. Simulation results illustrate the superior performance of the proposed method for residual vibration suppression.