Abstract: Bionic Ankle Tensegrity Exoskeleton (BATE) effectively maps the human musculoskeletal system, exhibiting excellent self-supporting properties and joint compliance, with biomechanical characteristics highly compatible with human motion. Previous research extensively investigated the mechanism of active muscle strings in BATE, but the influence of passive muscle strings, crucial in musculoskeletal models, on human-exoskeleton interaction remains unclear. Addressing the mismatch between interaction forces/moments and human motion demands in exoskeleton models with constant passive string stiffness, this paper reconstructs the constitutive function of passive muscle strings using the Parallel Elastic (PE) element of the Hill-type muscle model, which effectively simulates the dynamic contraction characteristics of muscletendon tissues. An interaction solution algorithm based on the Stiffness Mapping Method (SMM) is established to optimize the parameters of the biomimetic passive string constitutive function. This optimization achieves stable supporting force output while significantly reducing normal pressure, leading to superior interaction performance. Furthermore, the influence mechanism of passive string stiffness modulation on interaction within the BATE tensegrity exoskeleton is deeply explored, and stiffness modulation strategies for different interaction objectives are proposed.

Key words: Tensegrity exoskeleton')">Tensegrity exoskeleton, Hill-type muscle model, Stiffness mapping method, Interaction optimization