Robust Force Control of Series Elastic Actuators

Actuators

Andrea Calanca¹  Luca Capisani² 

[1] Department of Computer Science, University of Verona, Strada Le Grazie 15, Verona 37134, Italy;

关键词: series elastic actuators;    force control;    human-robot interaction;    robust control;    sliding mode control;   

DOI  :  10.3390/act3030182

来源: mdpi

【 摘 要 】

Force-controlled series elastic actuators (SEA) are widely used in novel human-robot interaction (HRI) applications, such as assistive and rehabilitation robotics. These systems are characterized by the presence of the “human in the loop”, so that control response and stability depend on uncertain human dynamics, including reflexes and voluntary forces. This paper proposes a force control approach that guarantees the stability and robustness of the coupled human-robot system, based on sliding-mode control (SMC), considering the human dynamics as a disturbance to reject. We propose a chattering free solution that employs simple task models to obtain high performance, comparable with second order solutions. Theoretical stability is proven within the sliding mode framework, and predictability is reached by avoiding the reaching phase by design. Furthermore, safety is introduced by a proper design of the sliding surface. The practical feasibility of the approach is shown using an SEA prototype coupled with a human impedance in severe stress tests. To show the quality of the approach, we report a comparison with state-of-the-art second order SMC, passivity-based control and adaptive control solutions.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.