Passive periodic motions of multi-joint robots by stiffness adaptation and DFC for energy saving

This paper presents a new energy saving control method for multi-joint robots to generate passive periodic motions, which require less actuator torque. Generally, if we do not use actuator torque, multi-joint robots with elastic elements will generate chaotic motion due to nonlinearity of multi-joint-robot dynamics. To solve this problem; stiffness adaptation and DFC are simultaneously used in our study. The proposed controller works without using parameters of the controlled systems, Numerical simulations demonstrate its effectiveness.