面向桁架攀爬的三分支机器人步态规划方法

Gait Planning Method for Climbing of Trinal⁃branch Robot on Truss Structures

为解决载荷大范围在轨平稳搬运问题,设计三分支机器人面向桁架攀爬的步态规划方法,使其能够平稳搬运载荷运动到部署位置完成大型航天器组装任务。以21自由度三分支机器人为研究对象,结合桁架结构划分多种攀爬步态单元;针对每种步态单元规划了单元周期内2条攀爬分支的交替夹持顺序以及末端的夹持位姿;针对大范围桁架搬运任务,基于可夹持区域构建表征桁架表面任意两杆间可过渡性的邻接矩阵,并利用Floyd算法生成距离矩阵与路径矩阵,规划出任意两杆间的最短攀爬路径,并将路径中的桁架杆件节点序列映射为机器人可执行的步态单元序列;基于三次B样条曲线对每种步态单元周期内2条攀爬分支的末端轨迹进行规划,实现攀爬分支末端在两夹持点间的攀爬过渡。仿真实验表明:所设计的步态规划方法能够使机器人实现在不同位置关系的桁架杆件之间的过渡,从而具备到达桁架表面任意位置的能力。

With the continuous advancement of manned space technology and the deepening of space exploration,the on⁃orbit construction of large spacecraft has become an important issue under the development and planning of major spacefaring nations.These spacecraft typically use large space trusses as support structures,facing the challenge of long⁃distance on⁃orbit transportation of loads such as truss rods,truss segments,and functional modules during their assembly.To address the problem of large⁃scale,stable on⁃orbit load transportation,a gait planning method for a three⁃branch robot aimed at truss climbing was designed to enable stable load movement to deployment positions for the assembly of large spacecraft.A 21⁃degree⁃of⁃freedom three⁃branch robot was used as the re⁃search object,and various climbing gait units were devised in conjunction with the truss structure.For each gait unit,the alternating clamping sequence of two climbing branches and the clamping postures of the end effectors within the unit cycle were planned.For large⁃scale truss transportation tasks,an adjacency matrix representing the transition ability between any two rods on the truss surface was constructed based on the clamping regions,and the Floyd algorithm was utilized to generate distance and path matrices,thereby planning the shortest climbing path between any two rods.The sequence of truss rod nodes in the path was then mapped into executable gait unit sequences for the robot.The end trajectories of the two climbing branches within the unit cycle were planned using cu⁃bic B⁃spline curves,achieving the climbing transition of the branch ends between two clamping points.Simulation experiments showed that the designed gait planning method enabled the robot to transition between truss rods with different positional relationships,thereby allowing it to reach any position on the truss surface.