| With the deepening of the research on the ground mobile platform,the advantages of multi-legged mobile robot are gradually highlighted.Compared with wheeled and tracked mobile robots,the discrete contact mode between the foot and the ground of legged mobile platform makes it have higher adaptability to complex environment.The close-chain multi-legged platform of foot robot has the advantages of high bearing capacity,few degrees of freedom,simple control and so on.On this basis,aiming at the bottleneck problems of close-chain multi-legged platform,such as single foot trajectory,lack of flexibility and obstacle surmounting performance,a series of researches are carried out.Firstly,through the research on the characteristics of the existing multi-legged closechain walking module,based on the Watt-I close-chain leg mechanism,the obstacle climbing performance of the multi-legged platform under the reconfiguration operation is mined,and the mechanism size is adjusted by two parameters coupling,and the closechain eight-legged adjustable module is proposed.The function relation surface of foot trajectory characteristic parameters(leg lifting height,span step length,fluctuation value)is established in Matlab,and the optimal reconstruction adjustment ratio of rod length parameters and inclination parameters is evaluated by entropy weight method,variation coefficient method and combination weighting method,so as to determine the optimal matching path of frame rod length and module inclination parameters.Secondly,the integral truss is decoupled to realize the rotational connection between the walking module and the frame.According to the vibration reduction requirements of the close-chain multi-legged platform,a torsion beam suspension is designed to connect the frame and the walking module elastically,which improves the flexibility and vibration reduction performance of the whole machine.Solid Works and Hyper Mesh were used to build the three-dimensional model of torsion beam,and the mesh was divided.The static stress and free modal analysis were carried out by ANSYS,which verified that the torsion beam suspension can meet the requirements of walking platform.Based on the design of close-chain multi-legged mechanism,the performance of close-chain multi-legged platform and obstacle surmounting strategy(vertical wall and longitudinal slope)were analyzed by Adams: for vertical wall obstacle,the maximum vertical climbing height was obtained by dynamic simulation method,obstacle surmounting grade was divided in Matlab based on simulation data,and the climbing strategy of full cycle vertical wall obstacle was formulated,The vertical climbing height is increased by 156.1%,and the fluctuation of the center of mass of the whole machine is reduced by 58.7%;According to the characteristics of dual-adjustment device,the climbing strategy of longitudinal slope is formulated,which increases the fit degree with the slope.Compared with the pitching platform,the centroid fluctuation of the whole machine is reduced by 62.2%,and the climbing stability of longitudinal slope is improved.Finally,the prototype is designed according to the verification requirements.Based on the results of dynamic simulation analysis,the selection and layout of drive motor,double regulating motor and control system are carried out.At the same time,the standard parts are selected according to the size of the prototype,and the engineering drawings of the machined parts are drawn;The four legged adjustable module of the prototype is assembled and debugged,and the feasibility of the dual parameter adjustment design is verified by the results of bench test;The whole machine was assembled and debugged,and the straight running,steering and vertical wall climbing tests were carried out to verify the correctness of the design. |
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