A Rhythmic Motion Control Method Inspired by Board Shoe Racing for a Weight-Bearing Exoskeleton

To ensure the flexible walking of the weight-bearing exoskeleton robot, most researchers control the exoskeleton to follow the wearer’s movements and provide force to maintain the current dynamic state. However, due to the limitation of sensing information and computing power, it is difficult for the exoskeleton to provide the wearer reasonable and stable force only based on the dynamic model, especially in switching between swing phase and stance phase. Inspired by China’s traditional sport named board shoe racing, a walking control method based on the cooperation of the human and the exoskeleton is proposed in this paper for a lower-limb exoskeleton named PALExo. Under certain conditions, the exoskeleton itself can walk stably depending on the rhythm signals generated by the Central Pattern Generator (CPG). With certain initiative during walking, it can make proper adjustments according to the human movement. With the help of dynamic simulation software and Genetic Algorithm (GA), the optimized CPG parameters are obtained. Impedance control is introduced to increase the comfort of the wearer. The impedance parameters as well as the CPG parameters are tuned in real time based on feedback. The experiments were conducted with PALExo. The results demonstrate that PALExo can effectively assist the wearer walking with a 45-kg payload benefiting from the proposed method.