Research On Structural Optimization Design Of Legs Of Foot-tracked Construction Robot

With the rapid development of urbanization,large and super high buildings are increasing,and the concept of intelligent construction has emerged,which is safer and more efficient.As the core equipment of intelligent construction,construction robot has high research value.Compared with conventional construction robots,foot-tracked construction robots can move with legs alone,with higher flexibility and mobility.Therefore,in this paper,the leg of foot-tracked construction robot is selected as the research object.The basic configuration of the leg is preliminarily designed,and the structural optimization design of the legs is studied in many aspects and multi-levels,which improves the performance of the legs of the robot.Firstly,referring to the ants in nature,the overall scheme of the robot legs and the basic configuration of the single leg are designed.The coordinate system of swing phase leg and support phase leg is established by D-H method,and the forward and inverse kinematics analysis is carried out.The workspace of swing phase leg is solved by Monte Carlo method.Secondly,to improve the kinematics performance of different working conditions of the leg,the length ratio of each leg joint is optimized.Among them,the concepts of improved workspace and average operability are proposed to obtain the optimal ratio of leg length for both.To solve the difficult problem of solving the conventional analytical method,the ADAMS virtual prototype simulation experiment was designed to study the relationship between the optimal body flexibility of the robot and the ratio of the leg length.Thirdly,to improve the dynamic performance of legs,the geometric size parameters of legs are further optimized.The trajectory planning of the swing phase leg is carried out by using the quintic polynomial.Based on the trajectory,the dynamic equation of the leg is established by Lagrange method,and the torque variation curve of each joint of the leg is obtained.The optimization variables,objective function and constraint conditions are selected and solved by genetic algorithm.The optimized geometric parameters of each leg joint are obtained,and the peak torque and energy consumption of each leg joint are improved.ADAMS was used to design the dynamic simulation experiment.The experimental results show that the driving power of each joint of the optimized leg decreases significantly,which proves the rationality of the optimization.Finally,the static analysis and modal analysis of the leg were carried out by ANSYS Workbench.The variable density method based on SIMP is used to realize topology optimization of leg femur and then the structure is reconstructed.Through the static analysis and modal analysis of the optimized leg again,the feasibility of topology optimization is verified,and the lightweight design of leg structure is proved to be reasonable.