A Study on Series Elastic Actuator Applied for Human-Interactive Robot

This paper studies the development of series elastic actuators (SEAs) utilized as a power transmission for human-interactive robots and exoskeletons. By applying this type of actuator, a joint mechanism can provide low output impedance, large force range and bandwidth, high fidelity of force control, and tolerance to shocks. First, a prototype of SEAs is developed using two elastic elements with various stiffness that can produce a desired joint torque based on the reference walking gait of human. Then, a mathematical modeling of SEAs is achieved to investigate the kinematic and dynamic of SEAs. In order to operate SEAs, a traditional PID controller is adopted, which is developed based on the pole placement method to stabilize the dynamic system of SEAs. The effectiveness and reliability of SEAs are evaluated through simulation and experimental results on a test-bench.