Research on The Design of Quasi-Passive Variable Stiffness Assisted Exoskeleton with Ankle

Abstract In order to reduce the torque generated during plantar flexion of the human ankle and alleviate leg muscle fatigue, a quasi-passive variable stiffness ankle assisted exoskeleton was designed. By using plantar pressure signals to control the electromagnetic clutch, energy storage and release of the energy storage unit were achieved. Firstly, the variable stiffness mechanism adjusts the preload force of the assist spring through geometric structure, achieving non-linear joint output stiffness and reducing energy consumption during human walking. Secondly, a simulation model of human ankle exoskeleton wearing was established, and dynamic simulation was conducted to verify the rationality of the exoskeleton mechanical structure and its good assistance effect. Finally, an experimental platform for testing the function of ankle assisted exoskeletons was established, and the performance of the variable stiffness energy storage mechanism was tested. The results showed that the average EMG signals of the tibialis anterior muscle and gastrocnemius muscle decreased by 12.29% and 39.26% after wearing exoskeletons, indicating that wearing exoskeletons effectively reduces muscle fatigue and provides a new method for the design of wearable exoskeletons.