In context
In 2024, exoskeleton development had advanced rapidly in control and intelligence, yet structural design lagged, with serial anthropomorphic exoskeletons suffering from human-machine joint misalignment. This misalignment caused mechanical constraints and reduced wearability, prompting research into alternative architectures.
What was reported
Researchers at the Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, proposed a parallel hip exoskeleton to eliminate joint misalignment and the tedious pre-wear alignment process. The design uses two UPS (universal-prismatic-spherical) branches per leg, with the wearer's thigh acting as a link, achieving all hip degrees of freedom and assisting flexion/extension and abduction/adduction.
To address the coupled actuation inherent in parallel structures, they developed a control method based on a human-machine integrated dynamic model. The model treats the human and exoskeleton as a unified 15-link system with nine generalized coordinates, derived using D'Alembert's principle of virtual work. This enables coordinated control of branch actuators, with desired forces computed in real time based on the system's state.
A prototype was built and tested in one motion pattern experiment and four assistive experiments. Results demonstrated good kinematic compatibility and effective assistive performance, with assistance scaling naturally with walking speed.
Why it mattered
This work advanced exoskeleton design by addressing the long-standing joint misalignment problem through a parallel architecture, while introducing a control framework that incorporates human dynamics—an approach rarely seen in prior exoskeleton control. It offers a path toward more comfortable, efficient wearable robots for rehabilitation and human augmentation in industrial settings.
"The results demonstrate the kinematic compatibility of the proposed hip exoskeleton and the assistive performance of the controller."
Source: 《机器人》期刊 (robot.sia.cn) · Published 2024-05-08 · “并联式髋关节外骨骼设计与基于人机耦合动力学方法的系统实现”