EAAI Journal 2025 Journal Article
Adaptive Coordinated Motion Planning for lower limb exoskeleton robots with a robotic walker
- Chaobin Zou
- Yi Ren
- Rui Huang
- Xinhao Zhang
- Jingting Zhang
- Zhinan Peng
- Hong Cheng
Repetitive gait training is helpful for patients with gait disabilities and can be effectively facilitated by lower limb exoskeleton robots (LLEs). At the early stages of rehabilitation, the deployment of a mobile robotic walker to complement exoskeleton-assisted gait training is indispensable, particularly for patients with diminished muscle strength. It is a critical issue to coordinated control the exoskeleton robot and the robotic walker to achieve a natural walking posture due to the variations of gait patterns with different walking speeds. In this paper, a novel Adaptive Coordinated Motion Planning (ACMP) approach is proposed to tackle the coordinated control problem of the LLEs with a robotic walker, which comprises of three parts: the gait patterns generation for LLEs, the optimization for adaption to the desired walking speed, and the coordinated control for both the exoskeleton robot and the robotic walker. The main contribution of this paper is twofold: a new knee-stretched gait patterns generation approach with the given foot locations; based on the reduced order dynamics model for the human–exoskeleton system, an optimization problem is constructed to generate reference joint angles for the human–exoskeleton–walker system and adapt to different walking speeds. Experimental validation was conducted on the CoppeliaSim simulation platform. Results demonstrate that the proposed approach achieves coordinated motion control across a wide speed range (0–0. 8 m/s), with the mean displacement tracking error of the center of mass constrained within 0. 01 m. This ensures accurate locomotion tracking of the LLEs while maintaining natural walking postures. Compared to non-adaptive baselines, the proposed method achieves a tracking accuracy improvement of over 92%, highlighting its effectiveness in dynamic human–robot coordination tasks.