Dynamics, stability, and energy efficiency of an energy-recycling rimless wheel with spring-clutch legs
For legged locomotion researchers, this work presents a novel mechanism that improves energy efficiency in passive walking, though the improvements are incremental and domain-specific.
This paper proposes an energy-recycling rimless wheel with spring-clutch legs that stores and reinjects impact energy, achieving up to 16.13% reduction in Cost of Transport (CoT) compared to a viscoelastic-legged benchmark and over 50% reduction compared to a rigid rimless wheel. Prototype experiments demonstrate passive walking on a 1° slope with a CoT of approximately 0.02.
This paper proposes an energy-recycling rimless wheel with spring-clutch legs. The proposed mechanism uses a lockable clutch to store part of the impact-induced elastic energy after foot contact and reinject it in the next gait cycle. First, we develop a hybrid dynamic model of the energy-recycling rimless wheel. Second, numerical simulations are used to examine the dynamics, local stability of periodic gaits, and the Cost of Transport (CoT) of the proposed mechanism. The simulation results show that the proposed mechanism reduces the CoT by up to 16.13% compared with a benchmark viscoelastic-legged rimless wheel with telescopic spring-damper legs. Compared with the rigid rimless wheel, the viscoelastic-legged and energy-recycling models reduce the CoT by more than 50%. The energy-recycling model also maintains locally stable periodic gaits over the tested slope and stiffness ranges. Finally, prototype experiments on an inclined plane are conducted to examine the feasibility of the proposed mechanism. The experimental results show that the proposed rimless wheel achieves passive walking on a shallow 1° slope, corresponding to a CoT of approximately 0.02. These results suggest that the proposed spring-clutch mechanism can improve the simulated walking efficiency of the energy-recycling rimless wheel, while the prototype experiments support the feasibility of passive walking with the mechanism.