随着太空探索的深入和空间技术的提高，大型航天器的在轨建造已成为重点研究方向，该类航天器通常以空间大型桁架作为支撑，需要依靠空间机器人完成多种载荷的在轨搬运与装配。由于其桁架结构具有大柔性、低阻尼的特点，空间机器人攀爬抓持桁架时易引发时变动态的桁架结构振动，从而影响载荷搬运的平稳性。为此，针对三分支机器人桁架攀爬中抓持构型优化问题，以“桁架-三分支机器人”复合系统为研究对象开展其接触碰撞特性分析；面向抓持构型构建攀爬平稳性、抓持平衡性和可操作性评价指标；利用多目标优化算法NSGA-Ⅱ建立以三分支机器人关节角度为决策变量的抓持构型优化模型，得到兼顾接触碰撞激励抑制、任务效率与机器人可操作性的抓持构型优化方法；最后通过对照仿真实验评估了该方法的有效性，为大型航天器桁架攀爬运动的平稳规划提供了分析手段和解决思路。

With the advancement of space exploration and technology， the on-orbit construction of large spacecraft has become a key research focus. These spacecraft typically use large space trusses as support structures and rely on space robots to carry out various on-orbit transportation and assembly tasks. Due to the characteristics of the truss structures， which have high flexibility and low damping， vibrations in the truss structure can be easily induced by time-varying dynamics when the space robot climbs and grasps the truss. This can affect the stability of load transportation. To address the holding configuration optimization problem for a three-branchrobot climbing a truss， the “truss-three-branch robot” composite system was used as the research object to analyze its contact and collision characteristics. Evaluation metrics for climbing stability， holding balance， and operability were constructed for the holding configuration. The NSGA-Ⅱ （Non-dominated Sorting Genetic Algorithm-Ⅱ） multi-objective optimization algorithm was used to establish a holding configuration optimization model with the joint angles of the three-branch robot as decision variables. This approach provided an optimized method for holding configuration that balanced contact collision excitation suppression， task efficiency， and robot operability. Finally， the effectiveness of this method was evaluated through comparative simulation experiments， offering analytical means and solutions for the smooth planning of truss climbing motions in large spacecraft.