Characteristic Model Based Position Control for Series Elastic Actuators

Abstract

Serial elastic actuators is capable to handle flexible tasks owing to its compliance to environment, and thus have attracted much attention recently. Comparing to force control issues, position control of SEA seems much harder because the order of system is high and SEA would also suffer from parameter uncertainties and disturbances. Therefore, in this paper, we proposed a characteristic model based control strategy for motion control of SEA, which has a simple structure and easy to implement. The simplified model using characteristic modelling is second order, and then a discrete sliding mode controller is designed considering external disturbances. Unlike traditional simplified modelling method, by using characteristic method, the derived model does not lose dynamic feature of the system. Examples and numeral simulations are provided to validate the effectiveness of both the characteristic model and the control scheme.