A Pin-Array Structured Climbing Robot for Stable Locomotion on Steep Rocky Terrain

TL;DR

This paper introduces a climbing robot with compliant pin-array grippers that passively adapt to rough surfaces, enabling stable locomotion on steep rocky terrain without complex sensing or control systems.

Contribution

The novel pin-array structured grippers with passive compliance improve surface adaptation and stability, reducing control complexity for climbing robots in unstructured environments.

Findings

Robust climbing demonstrated on inclined walls and rocky terrain

Passive compliance enhances grip stability and adaptability

Mechanical redundancy reduces grasping uncertainty

Abstract

Climbing robots face significant challenges when navigating unstructured environments, where reliable attachment to irregular surfaces is critical. We present a novel mobile climbing robot equipped with compliant pin-array structured grippers that passively conform to surface irregularities, ensuring stable ground gripping without the need for complicated sensing or control. Each pin features a vertically split design, combining an elastic element with a metal spine to enable mechanical interlocking with microscale surface features. Statistical modeling and experimental validation indicate that variability in individual pin forces and contact numbers are the primary sources of grasping uncertainty. The robot demonstrated robust and stable locomotion in indoor tests on inclined walls (10-30 degrees) and in outdoor tests on natural rocky terrain. This work highlights that a design emphasizing passive compliance and mechanical redundancy provides a practical and robust solution for real-world climbing robots while minimizing control complexity.