[2022-Vol.19-Issue 2]Design of a Minimally Actuated Lower Limb Exoskeleton with Mechanical Joint Coupling
Post: 2022-04-13 14:56  View:165

Journal of Bionic Engineering (2022) 19:370–389 

Design of a Minimally Actuated Lower Limb Exoskeleton with Mechanical Joint Coupling 

Hui Li1,2,3 · Hongliu Yu1,2,3  · Yingwei Chen4  · Xinyi Tang1,2,3 · Duojin Wang1,2,3 · Qiaoling Meng1,2,3 · Qing Du5

1 Institute of Rehabilitation Engineering and Technology, University of Shanghai for Science and Technology, Shanghai 200093, China
2 Shanghai Engineering Research Center of Assistive Devices Institute of Rehabilitation Engineering and Technology, Shanghai 200093, China
3 Key Laboratory of Neural-Functional Information and Rehabilitation Engineering of the Ministry of Civil Afairs, Shanghai 200093, China
4 Department of Gastroenterology, Xinhua Hospital Afliated to Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
5 Department of Rehabilitation Medicine, Xinhua Hospital Afliated to Shanghai Jiaotong University School of Medicine, Shanghai 200092, China 

Abstract  Powered lower limb exoskeletons have traditionally used four or more powered joints to provide ambulation assistance for individuals with spinal cord injury. Exoskeletons with numerous powered joints commonly lost some excellent features of passive orthoses and further decreased utility due to added weight and increased control complexity. This work adopts joints coupling mechanism to design a powered exoskeleton to minimize the number of actuated joints and control complexity. Unlike conventional powered exoskeletons, the joint-coupled-powered exoskeleton only has a single motor-actuated joint for each exoskeleton leg in conjunction with a unique knee coupled system to enable their users to walk, sit, and stand. And two types of joint coupled systems are designed, respectively, hip-knee coupled and knee-ankle coupled. The joint-coupled powered exoskeleton system allows a single actuator to power the hip motion, and allows activate knee motion through the coupled motions of the hip or ankle. More specifcally, when the mechanical coupled system is activated, the knee joint is unlocked, resulting in synchronized hip-knee or ankle-knee fexion and extension. The coupling mechanism is switched on and of at specifc phases of the gait (the stance phase and the swing phase) to generate the desired motions. The research work proves that minimal actuated robotic systems with joint coupled could achieve safe and natural walking. 

Keywords  Powered exoskeleton · Minimal actuation · Joint coupling · Single motor-actuated joint


Description of a walking gait cycle events. a Traditional gait cycle illustration; b new three-phase gait cycle illustration; c coupled activation timing

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