Design and Development of an Inchworm-Like Robot with Its Generalized Climbing Path Planning

This paper presents a novel 6-degree-of-freedom (DOF) inchworm-like robot inspired by bionics, designed to perform pipe inspection tasks with high flexibility in complex, unstructured environments. To determine the optimal dimensions of each link, a Nash bargaining solution-based multi-objective optimization framework is developed, evaluating performance indicators such as reachable workspace, global manipulability, and acceleration capability. Inspired by the inchworm locomotion, three distinct climbing gaits are designed to enhance adaptability in confined and irregular spaces. To ensure safe and reliable operation, transition analysis is conducted and the operational workspace is systematically calculated. Moreover, a novel global path planning algorithm specially designed for the inchworm-like robot, termed inchworm-like robot rapidly-exploring random tree (ICHRRT*), is proposed. As an improved algorithm of RRT*, this method integrates gait planning and transition analysis to generate feasible and collision-free paths tailored to the robot’s unique structure and motion characteristics. A physical prototype is developed, and truss-crossing experiments are conducted in a truss environment. Experimental results validate the robot’s superior climbing capability and its effectiveness in navigating obstacles.