Simultaneous Optimization of Trajectory and Parameter for Biped Robot with Series Elastic Actuators

摘要

Nowadays, robots are being introduced to various fields. Since existing environments and tools are designed for humans, humanoid robots are particularly expected to be adaptable to human society and highly versatile. Recent researches proposed using Series Elastic Actuators (SEAs) as actuators of biped robots. In the SEA, a motor and a link joint are connected by a spring, therefore it enables to reduce the damages to the motor which are caused by high-frequency impact forces owing to elasticity. However, it is still a challenging problem to determine the stiffness of SEAs and control input. Furthermore, conventional walking robots have a more serious problem that they are not energy efficient and cannot work continuously for a long time. This paper presents a method for biped robots with SEAs to walk efficiently, by optimizing each joint trajectory and spring stiffness simultaneously. We also propose a trajectory tracking control method using input-output linearization, and the performance of the proposed controller is verified with a numerical simulation.