Analysis of the Obstacle-Crossing Capability for a Coupled Parallelogram Leg

This paper presents the kinematic analysis of a coupled parallelogram leg (CPL) used for locomotion in a hexapod robot. The ability to cross obstacles is a crucial functionality of legged robots, which heavily relies on their control algorithms and structural characteristics. In this study, we specifically focus on analyzing the CPL workspace and propose three performance metrics for assessing its obstacle-crossing (OC) capabilities: workspace utilization, effective obstacle-crossing area ratio, and maximum stride ratio. By calculating these metrics for two main walking directions, we thoroughly evaluate the CPL’s OC abilities. The results offer valuable insights into the maximum stride and the starting and ending footholds in each direction, providing a solid theoretical foundation for the development of flexible OC strategies. Prototype experiments successfully validate the accuracy of these calculations, further confirming the effectiveness of the proposed metrics.