Improvement And Motion Analysis Of Six Bar Tensegrity Robot

The tensegrity structure can be seen as a spatial network structure composed of bar and string components.Due to the fact that the bar components are only subjected to compressive stress and the string components are only subjected to tensile stress,the structure exhibits light weight,large volume,and impact resistance.In the field of robotics,researchers have improved structural freedom by replacing string or bar components with brakes.Due to its symmetry and large internal space,the six-bar tensegrity structure is suitable for the structural foundation of rolling robots.Therefore,it has been studied by many scholars both domestically and internationally as the basic structure of planetary exploration robots.This article aims to improve and supplement the existing research on the six-bar tensegrity robot,and the main research content is as follows:1)The mathematical modeling of the standard six bar tensegrity structure is carried out to obtain the relationship between the length of the bar and the string and the stress relationship.By analyzing the design defects and deficiencies of the existing bar driven tensioning overall robot,the improvement scheme of the tensioning overall robot in this paper is proposed.Some key parts are redesigned,selected and checked,and the spring parameters are selected from the aspects of the robot’s structural stability,deformation performance,etc,Obtain a three-dimensional model of the tensioned overall robot.Considering the requirements of circuit protection and motor heat dissipation,the communication unit,sensor unit,driving unit and transmission mechanism are integrated into a single bar member,avoiding the influence of unreasonable structure mass distribution on the deformation movement of the robot.2)Using shape functions to describe bar and string components,establish a finite element model of the system.Based on the Lagrange equation,derive the general dynamic equation and constrained dynamic equation,intbaruce a ground contact force model,and construct a simulation program for the tensegrity system;Redefining the robot’s motion gait,combining genetic algorithm to optimize and control the centroid movement trajectory of a single gait robot,searching for the fully driven optimal control strategy,and obtaining the control curves of all drivers.3)A detailed design of the electrical control system of the tensegrity robot was conducted from the perspectives of demand analysis,device selection,schematic diagram,PCB,etc.Combined with the structural design mentioned earlier,a complete design scheme for the physical prototype of the tensegrity robot was formed,and a robot prototype was built according to the design scheme;By defining the robot landing on the ground,the driving strategy searched in the previous text is extended to all gait of the robot.Combined with the classical PID control of the position loop acceleration loop,single gait motion experiments are conducted,and experimental data and gait errors are analyzed to describe,define,and quantify the pairwise relationship between the initial and final states of the single gait robot.4)Important issues such as pose recognition,gait connection,and direction decision-making in the continuous gait motion of a tensioned whole robot were proposed,and corresponding solutions were proposed based on the robot prototype and control data in this paper.On this basis,considering the average gait error,an obstacle free path planning scheme was obtained.The motion characteristics of the robot were combined with the potential field method to obtain a robot obstacle avoidance path planning scheme,Build an experimental environment around the camera module and conduct obstacle free and avoidance experiments separately.Analyze the experimental data to verify the feasibility of the planning scheme.