Study On The Design And Walking Performance Of A Single Power Reconfiguration Closed Chain Leg Mechanism

Compared with wheeled and tracked robots,walking mobile robots show stronger flexibility,adaptability and mobility in the face of complex terrain environment.Therefore,walking mobile robots are widely used in many fields and become a research hotspot of mobile robots.According to the form of branch chain,walking robots can be divided into two types: open chain type and closed chain type,the walking robot based on closed link has been widely concerned because of its advantages such as multi-leg and less driving,high frequency driving of crank turnover,high stiffness and high reliability of the whole closed chain.However,its single foot trajectory reflects the disadvantage of its low adaptability,which limits its application scenarios.Therefore,it is of great significance to design a closed chain multi-legged robot with high obstacle jumping ability and high walking comfort for expanding the use value of closed chain multi-legged robot.In this paper,the ideas of reconfigurable,dynamic coupling and support compensation are introduced to improve the design and analysis of the traditional single-DOF closed-chain linkage leg mechanism.A new design process based on the traditional closed-chain linkage leg mechanism is described.Based on the new configuration obtained at last,a new bi-quadruped robot is constructed.Based on the Watt-Ⅰ type six-bar seven-leg mechanism.Firstly,by introducing the construction element reconfigurable design method,a mobility degree of freedom is added to the frame.By changing the length of the frame rod,the height of the lifting leg in the swing phase of the mechanism is improved to realize the high lifting leg movement,so as to improve the ability and adaptability of the mechanism to overcome obstacles.Secondly,after the reconfigurable design,in order to avoid the complexity of the control system caused by the addition of new driving forces,the dynamic coupling design can be introduced to achieve the purpose of power normalization and maintain the single-degree-of-freedom characteristics of the mechanism.Finally,by introducing the rigid body inversion method,the foot trajectory of the support phase was designed for fluctuation compensation,so as to reduce the centroid fluctuation of the frame in the process of walking,realize the stable support of the platform,and avoid the energy loss and velocity fluctuation caused by the centroid fluctuation.After the above design process,a new closed-chain linkage leg mechanism configuration is finally obtained.This configuration maintains the characteristics of closed chain linkage leg mechanism,such as single degree of freedom,multi-leg less driving,high stiffness and large bearing capacity,and improves the problems of single track,insufficient adaptability and running comfort.Based on the new configuration,the layout and design of the whole machine are carried out,and the corresponding dynamic model is established.The performance of the platform,such as straight line,steering,climbing and crossing,is analyzed.Finally,a prototype is developed and the relevant tests are carried out to verify the feasibility and correctness of the theory.