Structural Design And Characteristic Analysis Of Legged Walking System Of Hexapod Wheeled Walker

In order to greatly improve the carrying capacity under extremely complex terrain such as high and steep mountains,snow and ice,churning ground and so on,there is an urgent need for a new carrying platform,which adopts an innovative designed walking and driving system,with both the rapid passing ability under paved roads and the strong obstacle crossing ability under extremely complex terrain conditions,so as to effectively meet the urgent needs of material transportation in China’s mountainous border areas.This paper puts forward an innovative design idea of organically integrating the foot walking system into the wheeled vehicle,which can effectively adapt to the complex terrain environment of rugged and steep mountains.In this paper,a bionic foot walking system based on scaling mechanism is proposed for the first time,which realizes the motion decoupling in two orthogonal directions of foot trajectory of the walking system,and has large bearing capacity,high response speed and good control performance.This paper focuses on the key problems in the structural design,motion characteristic analysis,dynamic modeling and gait planning of this walking system based on zoom mechanism.The main research contents are as follows:Firstly,the functional requirements of foot walking system in special mountainous terrain are divided,a zoom mechanism is optimized,and the basic configuration of walking system is determined.Based on this configuration,the calculation of key parameters and structural design of bionic leg mechanism are completed,the structural optimization is completed by using lightweight technology,and the preliminary static strength check is carried out.According to the special use environment in mountainous areas,a plantar structure is designed,which can effectively meet the use requirements of some extreme environments.For the designed legged walking system,the kinematics model of the leg mechanism is established,the position transformation matrix of each rod is established by using the DH criterion,the DH parameters are obtained,the configuration characteristics of the mechanism are studied,the functions describing the forward and inverse kinematics of the mechanism are established in MATLAB,and the motion relationship of the mechanism rod system is analyzed based on the Jacobian matrix,The matrix describing the motion of the mechanism is established,and the motion characteristics and motion feasible region of the mechanism are studied.Then,three different methods are used to model the dynamics of the legged walking system.By comparing the modeling results of the three methods,the correctness of the dynamic model of the legged walking system is verified.At the same time,based on the dynamic model,the characteristics of single leg component centroid acceleration curve,the force between joints and the driving characteristics of hydraulic cylinder are studied,and the dynamic characteristics of leg mechanism are analyzed.Aiming at the Hexapod wheeled walker based on zoom structure,the gait of legged walking is studied,the motion planning of legged walking system under six different gait forms is analyzed,the obstacle crossing simulation model of wheeled walker is established based on ADMAS,and the force characteristics of legged walking system under different gait are analyzed.Through the joint simulation technology,the control system of wheeled walker is built in MATLAB,and the response characteristics of walking system under the action of complex foot ground interface force are studied.Finally,the engineering prototype of wheeled walker based on zoom bionic leg mechanism is designed,and the physical prototype of simulated leg mechanism and vehicle body are manufactured by using 3D printing technology.Based on the physical prototype,the experimental research on motion principle,driving mechanism and basic gait is carried out to verify the correctness of the proposed leg structure and the feasibility of the scheme.