Codesign of a Differential Three-Segment Leg Enhancing Payload and Efficiency in Quadrupeds

Roboticsrequires innovative design and system-level optimization to enhance performance. This study presents a differential three-segment leg and a codesign optimization framework aimed at improving the load capacity and energy efficiency of quadrupeds. The proposed leg design reduces the actuator torque for the same ground reaction force, decreasing the actuator Joule heating. The codesign framework simultaneously optimizes actuator, leg mechanism, and locomotion variables to minimize energy consumption. A hierarchical penalty function is used to address design constraints, such as leg workspace and actuator speed limits, transforming the constrained problem into an unconstrained one. Using the differential evolution algorithm, optimization is achieved efficiently, with convergence in 30 s. Based on these results, we developed the quadrupedal robot: Sirius-plus. Experimental validation, including single-leg swing tests and load-bearing walking trials, demonstrated the enhanced payload capacity and energy efficiency of our design.