Distributed series elastic actuator: Analysis and simulations

Series elastic actuators (SEA´s) have been widely used in rehabilitation robots and haptic devices to provide sufficient compliance as well as safety, among some other properties, for performing interactive tasks. Nevertheless, SEA´s suffer from two major drawbacks; namely short bandwidth and limited rendered stiffness. In this paper, we propose a new elastic actuator concept in that a set of spatially distributed and mechanically parallel SEAs, each called a SEA component, are grouped and control a single joint. We call our system distributed series elastic actuator (DSEA). Each SEA component has its own controller but gets its set point from a load distribution system. The analytical and the simulation results show that a DSEA has wider bandwidth and better transient performance in addition to elevated rendered stiffness in comparison to its equivalent SEA. In addition, DSEAs consume less energy and require lower power as well as torque.