A compact soft actuator unit for small scale human friendly robots

This paper presents the development of a new compact soft actuation unit intended to be used in multi degree of freedom and small scale robotic systems such as the child humanoid robot "iCub"[1]. Compared to the other existing series elastic linear or rotary implementations the proposed design shows high integration density and wider passive deflection. The miniaturization of the newly developed high performance unit was achieved with a use of a new rotary spring module based on a novel arrangement of linear springs. The model and the control scheme of the actuator are analysed. The proposed control scheme is a velocity based controller that generates command signals based on the desired simulated stiffness using the spring deflection state. The overall system is evaluated with experimental trials performed using a prototype unit. Preliminary results are presented to show that the unit and the proposed control scheme are capable of replicating virtual impedances within a wide range and with good fidelity.SCOPUS: cp.p