Actuators 2014, 3(3), 182-204; doi:10.3390/act3030182
Article

Robust Force Control of Series Elastic Actuators

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Received: 16 December 2013; in revised form: 16 May 2014 / Accepted: 30 May 2014 / Published: 9 July 2014
(This article belongs to the Special Issue Soft Actuators)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: 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.
Keywords: series elastic actuators; force control; human-robot interaction; robust control; sliding mode control
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MDPI and ACS Style

Calanca, A.; Capisani, L.; Fiorini, P. Robust Force Control of Series Elastic Actuators. Actuators 2014, 3, 182-204.

AMA Style

Calanca A, Capisani L, Fiorini P. Robust Force Control of Series Elastic Actuators. Actuators. 2014; 3(3):182-204.

Chicago/Turabian Style

Calanca, Andrea; Capisani, Luca; Fiorini, Paolo. 2014. "Robust Force Control of Series Elastic Actuators." Actuators 3, no. 3: 182-204.

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