Effects of Load Connection Form on Efficiency and Kinetics of Biped Walking

This paper investigates the influence of the load connection form on the walking energetics and kinetics with simple models. Four load connection forms including rigid connection (RIC), springy connection (SPC), swingy connection (SWC), and springy and swingy connection (SSC) were modeled. The step-to-step transition of periodic walking was studied through an analytical method. The toe-off impulse magnitude and the work done by toe-off were derived. Simulations were performed to study the walking performance of each model and the effect of model parameters on the gait properties. The analysis and simulation results showed that compared with RIC, SPC and SSC can significantly improve the toe-off efficiency and change the ground reaction force (GRF) profile by reducing the burden during the step-to-step transition, which may lead to reduction of walking energy cost. Energetics and kinetics of SWC are closely related to the swing angle of load at the transition moment. The load swing may decrease the walking speed, and it is not beneficial to walking efficiency.