A self-balancing anti-fall climbing robot with force–position cooperative control for T-shaped guide rails

Abstract

To address the low efficiency, high physical workload, and elevated fall risk associated with manual inspection and climbing operations on transmission towers, this study presents a rail-guided climbing robot integrating fall protection, power-assisted climbing, and force–position adaptive control for existing T-shaped guide rail fall-arrest infrastructures. The robot employs a rubber-wheel clamping climbing module driven by a multi-stage compound transmission and incorporates a self-balancing eccentric anti-fall mechanism to achieve adaptive regulation of climbing velocity and assistive support force. Based on the force-transmission characteristics of the climbing system, a force–position cooperative control framework is developed. The controller integrates a velocity-adaptive strategy with a closed-loop Proportional-Integral-Derivative (PID) velocity controller, in which the relative human–robot position is adopted to continuously regulate the climbing velocity during cooperative climbing assistance. Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulations indicate a steady-state motor torque of approximately 0.22 N·m at a constant climbing velocity of + 445 deg/s. During ascending motion, the mean contact forces of the mid-mounted drive wheel and the left/right drive wheels are 37.4 N and 26.8 N, respectively, while the corresponding values during descending motion are 68.4 N and 41 N. Prototype experiments exhibit basic consistency with the simulation results. Furthermore, experiments under different payload conditions and external disturbances validate the load adaptability, disturbance robustness, and stable climbing performance of the proposed system. The proposed system provides an effective solution for safe and adaptive human–robot cooperative climbing assistance in transmission-tower operations.