Design of a spider-inspired wheeled compliant leg for search mobile robots

Earthquake and other disasters nowadays still threat people’s lives and property due to their destructiveness and unpredictability. The past decades have seen the booming development of search and rescue robots due to their potential for increasing rescue capacity as well as reducing personnel safety risk at disaster sites. In this work, we propose a spider-inspired wheeled compliant leg to further improve the environmental adaptability of search mobile robots. Different from the traditional fully-actuated method with independent motor joint control, this leg employs an under-actuated compliant mechanism design with overall semi-tendon-driven control, which enables the passive and active terrain adaptation, system simplification and lightweight of the realized search robot. We have generalized the theoretical model and design methodology for this type of compliant leg, and implement it in a parametric program to improve the design efficiency. In addition, preliminary load capacity and leg-lifting experiments are carried out on a one-leg prototype to evaluate its mechanical performance. A four-legged robot platform is also fabricated for the locomotion tests. The preliminary experimental results have verified the feasibility of the proposed design methodology, and also show possibilities for improvements. In future work, structural optimization and stronger actuation elements should be introduced to further improve the mechanical performance of the fabricated wheeled leg mechanism and robot platform.