Bandwidth Limitations in Force Control of a Series Elastic Actuator with Backlash and Quantization

Series Elastic Actuator has been widely utilized in various robotic applications, where precise and compliant force control is required. In SEA, the amount of spring deformation, which is mainly controlled for the compliant force control of SEA, is not very large, and thus the feedback control of this spring deformation is very subject to various nonlinearity such as backlash and quantization. In this paper, the effect of this nonlinearity on the force control of SEA is investigated. In particular, how the feedback controller gains are affected by the nonlinearity is examined through experiments, and a guideline for the gain determination is suggested.