Motion planning trajectories for a multi-limbed robot to climb up walls requires a unique combination of constraints on torque, contact force, and posture. This paper focuses on motion planning for one particular setup wherein a six-legged robot braces itself between two vertical walls and climbs vertically with end effectors that only use friction. Instead of motion planning with a single nonlinear programming (NLP) solver, we decoupled the problem into two parts with distinct physical meaning: torso postures and contact forces. The first part can be formulated as either a mixed-integer convex programming (MICP) or NLP problem, while the second part is formulated as a series of standard convex optimization problems. Variants of the two wall climbing problem e.g., obstacle avoidance, uneven surfaces, and angled walls, help verify the proposed method in simulation and experimentation.

翻译：多肢体机器人攀爬墙壁的运动规划轨迹需要综合考虑扭矩、接触力和姿态等约束条件的独特组合。本文针对六足机器人在两面垂直墙壁间撑开并利用仅依赖摩擦力的末端执行器进行垂直攀爬的特定场景，重点研究其运动规划问题。不同于采用单一非线性规划求解器进行运动规划的方法，我们将该问题解耦为两个具有明确物理意义的部分：躯干姿态与接触力。第一部分可建模为混合整数凸规划或非线性规划问题，第二部分则转化为一系列标准凸优化问题。通过考虑避障、非平坦表面及倾斜墙壁等双壁攀爬问题的变体，我们在仿真和实验中验证了所提方法的有效性。