变胞机器人腿部结构轻量化设计

Lightweight design of leg structure of metamorphic robot

变胞机器人作为一种新型地面移动系统,能够通过重构变形在轮式行驶与腿足式行走间自然切换,与传统车辆相比,变胞机器人具有在结构路面上快速行驶及非结构路面上高通过性的优点。文章使用ADAMS建立变胞机器人多体动力学模型,通过仿真获得变胞机器人重构过程中腿部各连接部件的载荷谱;在变胞机器人腿部机构的设计基础上,以壁厚为优化变量,以质量和应力最小为优化目标,采用最优拉丁超立方试验设计配合四阶响应面法近似模型,并基于NSGA-Ⅱ算法对其进行多目标优化;在获得Pareto前沿后,运用提出的权重选择法确定一个最优解,根据最优解对腿部机构进行优化设计,并对优化设计后的腿部各构件进行强度仿真分析,且与优化前数据进行对比;最后采用应力测试试验对优化后的腿部机构与优化后的仿真结果进行比较。仿真和试验结果验证了该有限元模型的准确性及优化设计的有效性。

As a new type of ground mobility system, the metamorphic robot can naturally switch between wheeled driving and legged walking by reconfiguration deformation. Compared with traditional vehicles, the metamorphic robot has the advantages of fast driving on structured roads and high passability on non-structured roads. In this paper, the multi-body dynamics model of the metamorphic robot is firstly established by using ADAMS, and the load spectrum of each connected component of the leg during the reconfiguration of the metamorphic robot is obtained by simulation. Then, based on the design of the leg mechanism of the metamorphic robot, the optimal Latin hypercube experimental design with the fourth-order response surface approximation model is used with the wall thickness as the optimization variable and the mass and stress minimization as the optimization objective, and the multi-objective optimization is performed based on the NSGA-Ⅱ algorithm. After obtaining the Pareto front, an optimal solution is determined by applying the weight selection method proposed in this paper, and the leg mechanism is optimally designed according to the optimal solution. And the strength simulation analysis of each component of the leg after the optimized design is carried out and compared with the data before optimization. Finally, the optimized leg mechanism is compared with the optimized simulation results by means of stress test. The simulation and test results verify the accuracy of the finite element model and the effectiveness of the optimized design.