Series Elastic Actuator (SEA) has been utilized in various robotic applications, including exoskeleton, training robot and collaborative robots. The high-performance force control of SEA results in this successive application of it to this field as it can guarantee safe interaction between humans and robots.
However, there is still few research on high precision position control of SEA, as the elasticity introduced for the force control is beneficial for force control, but strictly limits the position control bandwidth/performance. This issue is considered a significant problem of SEA when it is applied for industry.
In other words, compliance can be easily achieved by SEA, while there is a limitation on the stiffness of the whole system driven by SEA. This problem is not only applied to SEA, but it has been considered an intrinsic problem of any flexible system.
Research to address this problem and achieve high performance position control of SEA is what we are doing.