Planning And Research On Obstacle-crossing Gait Of Tetrahedron Mobile Robot Based On Multi-closed-loop Linkage Mechanism

As an important auxiliary tool that helps humans expand the scope of their cognition,mobile robots are playing an increasingly important role in people's production and life.The polyhedron robot is a polyhedron form mechanism composed of a spatial multi-loop closed-chain linkage mechanism.In response to the high terrain adaptability requirements of the ground mobile robot,this paper analyzes the obstacle course of the tetrahedral mobile mechanism facing the step obstacle,proposes two obstacle-climbing gaits,and carries out theoretical analysis and prototype experiments on them.First,the configuration design of the branch chain of the tetrahedral moving mechanism is carried out,and the degree of freedom is analyzed according to the configuration design,and a rolling gait planning based on symmetrical driving is proposed.A collision-free rolling gait is proposed for its flat ground motion,and the complete process of the rolling gait of the mechanism is kinematically analyzed.Based on the polygonal support area of the tetrahedral moving mechanism,its moving trajectory is divided into triangular meshes,and the step obstacles are projected and distorted.From this,the mechanism's step-by-step obstacle crossing process for the step obstacles is planned,and the concave polyhedron is constructed to enclose it.The target obstacle increases the climbing height.According to the symmetrical characteristics of the mechanism motion gait,the equivalent plane mechanism method is used to establish the motion model of each step and analyze the obstacle parameters.According to the obstacle-climbing process of the tetrahedral moving mechanism,two obstacle-climbing gaits are proposed.Among them,the high center of mass climbing gait can increase the height of the center of mass through three-degree-of-freedom synchronous deformation,and improve the climbing ability of the mechanism;the enclosed climbing gait forms a concave polyhedron to form an enclosure on the step obstacles,thereby improving its climbing ability.A critical state kinematics model is established for each stage of the obstacle-crossing gait,and the expression of the center of mass coordinates of the mechanism with respect to the obstacle height and obstacle distance is obtained through the homogeneous transformation matrix.According to the numerical algorithm,the maximum obstacle-crossing height is obtained with the driving angle and the obstacle distance.Change the curve,execute movement to different obstacle stages to deal with obstacles of different heights.The dynamic simulation of the virtual prototype was carried out through Adams software to verify the rationality of the obstacle crossing analysis process.Finally,according to the analysis results,a principle prototype is designed and produced,and the prototype is divided and designed.Among them,the U sub-module is designed with a flexible hinge to meet the under-driving requirements of the mechanism.The feasibility of each moving gait of the organization was verified,and the experimental results conforming to the theoretical analysis were obtained.In this thesis,the movement planning and gait design of the tetrahedral moving mechanism facing the obstacle obstacle course of the step obstacle are carried out,and the theoretical model establishment and analysis of each stage of the obstacle obstacle gait,the simulation model construction and analysis and the principle prototype are carried out.The design and experiment verified the feasibility of the step-by-step obstacle-crossing gait of the tetrahedral moving mechanism and the rationality of the analysis method,providing new research ideas and analysis directions for the tetrahedral moving mechanism's ability to overcome obstacles,and providing a multi-circle space The extension of the motion capability of the closed-chain linkage mechanism provides new research ideas and application prospects.