Design of A Lower Limb Exoskeleton Driven by Tendonsheath Artificial Muscle * In the past decades, with the development of science and technology, lower limb exoskeletons have been developed quickly, which can help patients to walk or do rehabilitation training. In this paper, the design of a lower limb exoskeleton, named SEUEXO, will be presented in detail. The SEUEXO is driven by a new type of artificial muscle, which actuated by a motor and tendonsheath system based on Hill muscle model. In this structure, with a controllable clamper, a series spring and a parallel spring, this artificial muscle can mimics musclexe2x80x99s characteristics, and has better compliance and controllability. Based on the principle of bionics, the degrees of freedom for rehabilitation exoskeleton are allocated reasonably, the mechanical structure is presented, and the tendonsheath transmission path optimization method is studied. Finally, the evaluation experiments are verified, which proves the reliability and stability of the SEUEXO.

Design of a Series Elastic Actuator with Doublelayer Parallel Spring for Lower Limb Exoskeletons This paper presents a novel Series Elastic Actuator (SEA) with doublelayer parallel spring for lower limb exoskeletons (LLE). The SEA can improve the humanrobot interaction comfort and have the ability to absorb shock and vibration. In order to make the assembly process simple and convenient, the series elastic unit adopt split structure, which includes an inner ring structure, an outer ring structure and rectangular springs as elastic element. At the same time, in order to meet the requirements of the stiffness and dimensions of the SEA, a doublelayer parallel spring arrangement is adopted. The stiffness of SEA is 312Nmrad, which is obtained by the stiffness calibration experiment. In the experiments, the SEA is used in the knee joint of LLE and an impedance controller is designed to achieve knee joint tracking motion. Finally, the experiments results show the position tracking performance of the LLE, which illustrates the effectiveness of the SEA.