Mechanism design and trajectory planning of a kinematically redundant parallel climbing robot

Abstract

This paper proposes a kinematically redundant wall-climbing robot (CR), which employs a kinematically redundant parallel mechanism (PM) as its main body, combined with a serial mechanism, to achieve wall-climbing motion and avoid the dangers associated with manual operation. The improved Grübler-Kutzbach formula is utilized to analyze the degrees of freedom (DOF) of the PM. Subsequently, a kinematic analysis covering position, velocity, singularity, and workspace is conducted to establish the theoretical basis for the robot’s motion planning. To cope with complex working environments, trajectory planning is carried out for the CR, and the complex path planning problem in space is addressed through hierarchical processing, including global path planning, local path planning, and single-step motion planning. After theoretical analysis, kinematic, singularity, workspace analysis, and trajectory planning method of the proposed CR were verified through simulation experiments, confirming the correctness of the kinematic modeling and trajectory solution. Finally, a physical prototype was built to verify the climbing capability of the robot.