Advances in Hybrid Modular Climbing Robots: Design Principles and Refinement Strategies
Ryan Poon, Ian Hunter
TL;DR
The paper addresses the problem of achieving autonomous robotic climbing on tall structures with variable column diameters. It introduces CLIMR, a hybrid wheeled-climbing platform with modular tendon-driven arms and a cantilever tail that offsets the center of mass to enable self-locking, autonomous grasping, and rotation about the column, along with a design framework to evaluate adaptability and performance. The authors develop mathematical models linking the number of modular links, self-locking conditions, and drive-torque requirements, and validate them via simulations and experiments on PVC pipes, e.g., enforcing $d_1 \ge 120 \ \mathrm{mm}$ for self-locking and ensuring $F_{dr} \le F_W$ for no-slip, while targeting climbs of $100\ \mathrm{mm/s}$. Experimental results report climbing speeds around $100$--$144\ \mathrm{mm/s}$ across pipes with diameters of 90–220 mm, along with demonstrations of self-locking, rotation, and autonomous grasping, supporting the framework's practical relevance for automated industrial climbing tasks.
Abstract
This paper explores the design strategies for hybrid pole- or trunk-climbing robots, focusing on methods to inform design decisions and assess metrics such as adaptability and performance. A wheeled-grasping hybrid robot with modular, tendon-driven grasping arms and a wheeled drive system mounted on a turret was developed to climb columns of varying diameters. Here, the key innovation is the underactuated arms that can be adjusted to different column sizes by adding or removing modular linkages, though the robot also features capabilities like self-locking (the ability of the robot to stay on the column by friction without power), autonomous grasping, and rotation around the column axis. Mathematical models describe conditions for self-locking and vertical climbing. Experimental results demonstrate the robot's efficacy in climbing and self-locking, validating the proposed models and highlighting the potential for fully automated solutions in industrial applications. This work provides a comprehensive framework for evaluating and designing hybrid climbing robots, contributing to advancements in autonomous robotics for environments where climbing tall structures is critical.