Abstract
As a crucial technology in the field of extremity rehabilitation, exoskeleton robots main research direction aims at achieving precise control and advancing the dexterity of exoskeleton architectures. The unique structure of Bowden-cables makes them ideal for power transmission in lightweight wearable exoskeletons. However, realizing precise control of the exoskeleton system while accounting for the inherent limitations of Bowden-cable, such as friction and hysteresis, poses a complex challenge. This paper proposes a compact wearable exoskeleton designed for the purpose of rehabilitating the elbow and forearm. Firstly, we optimize the performance of the Bowden-cable transmission by incorporating redirection pulleys, while a mathematical model is developed to describe the Bowden-cable and pulley system (BCPS). Afterwards, guided by the principle of ergonomic concept, the mechanism design and size calculation of the exoskeleton are conducted. Moreover, an optimized sliding mode control strategy was implemented to control the exoskeleton, and the efficacy of the designed controller was assessed through trajectory tracking experiments simulating “eating” movements. Finally, the experimental results demonstrate that the root mean square errors (RMSE) for elbow and forearm angle tracking are 0.84° and 1.13° respectively, indicating that the designed exoskeleton is suitable for arm rehabilitation training.
