Design and Simulation Analysis of Quadruped Walking Mechanism for Inspection Robot for Fully Mechanized Mining Faces of Thin Coal Seams

To address the challenges of limited mining height, confined space, uneven floor conditions, high labor intensity, and significant safety risks in thin coal seam fully mechanized longwall faces, a quadruped inspection robot tailored for such complex environments is proposed, with particular emphasis on the design and simulation-based analysis of its walking mechanism. The robot can walk, cross obstacles, and climb slopes, featuring a lightweight and modular structure. Explosion-proof servo motors are centrally mounted on the main body to effectively reduce moving inertia and enhance overall stability. The walking mechanism comprises explosion-proof motors, linkage-type legs, a gear-shifting device, and a transmission system. A kinematic model of the leg mechanism is developed to investigate the influence of crankshaft mounting position on leg performance. Taking lift height and driving torque as optimization objectives, a multi-objective optimization model is formulated and solved using the NSGA-II algorithm in MATLAB. This yields high-performance installation regions and optimal mounting points for two distinct leg-lifting modes. To validate the walking mechanism’s performance, a virtual prototype of the quadruped robot and a 3D model of a thin coal seam longwall face are constructed. Dynamic simulations of the robot’s machine-following inspection process are performed in ADAMS. The results demonstrate that the robot reliably executes predefined gaits and exhibits excellent dynamic stability across four operational scenarios: level walking, obstacle crossing, slope climbing, and combined slope-climbing with obstacle traversal. It achieves a maximum obstacle-crossing height of 118 mm, a maximum walking speed of 15.6 m/min, and a maximum climbing angle of 10°, fully satisfying the requirements for machine-following inspection in thin-seam longwall operations. This work provides a practical foundation for advancing minimally manned and intelligent mining in thin coal seam fully mechanized faces.