Design And Performance Of Closed Chain Variable Topology Dual-mode Multi-legged Robot

With the rapid development of legged robot for many years,legged transport platform has been widely used in many fields.Compared with traditional modes of locomotion,such as wheeled and tracked locomotion,legged robots are playing an increasingly important role in mountainous environments,logistics and transportation,education and entertainment,and planet exploration.At the same time,compared with serial multilegged robots,closed-chain multilegged robots have fewer driving numbers,higher operating frequency and outstanding load capacity.However,due to its single legged trajectory and poor terrain adaptability,the closed-chain multilegged robots can be used in multiple scenarios.Therefore,it is of great research significance to develop a foot mechanism suitable for multi-scene and multi-trajectory,optimize and highlight the functional differentiation of dual-mode,and construct a multi-legged robot with dualmode on the basis of this.Faced with the problem of single gait trajectory mode of the closed chain mechanism,a design process of variable topology mechanism based on the existing closed chain configuration was proposed.Combined with the research ideas of mechanism bionics and related application scenarios,a closed-chain variable topological leg mechanism scheme which could realize two trajectory motion modes was completed according to the design process,and the scheme selection was completed based on sensitivity analysis.Furthermore,by means of scale synthesis,trajectory optimization of variable topology configuration was completed with the goal of high obstacle crossing in four-bar trajectory mode and high maneuverability in six-bar trajectory mode,and then the dimension parameters of the mechanism were determined.Based on the variable topology dual mode configuration,a multi-legged robot is constructed to realize the modularization of the two-legged robot,so that the whole machine has the advantage of modularization,so as to meet the differentiated use needs of multi-legged robots in the scene.The topology changes were expressed by matrix,and the kinematics analysis was carried out by using the vector loop method to draw the foot trajectory.Combined with the dynamics simulation,the kinematic characteristics,dynamic characteristics and maneuverability characteristics of the two modes were compared and analyzed to obtain the performance characteristics.From the theory of single leg configuration innovation,double foot module optimization to determine the layout of the whole machine,further complete the overall design of the whole machine,reasonable layout and drive,transmission,control system design.At the practical level,the prototype engineering design and production were completed,including the design and optimization of mechanical structure,the processing design of parts,the strength check of key parts,etc.Based on the completion of the prototype assembly of the closed-chain variable topology dual-mode multi-legged robot,and the bench test for the dual-mode theoretical goal,the correctness of the theoretical analysis and the feasibility of the design are verified.The innovation of this paper lies in completing the design of the variable topology configuration,and finally realizing the switching of two walking modes(four-bar mode and six-bar mode)based on the double-track mode.Among them,the four-bar trajectory mode has the characteristics of high lifting leg trajectory,so that the multi-legged robot has good terrain adaptability under the unstructured road surface such as mountain,step and ditch.The six-bar trajectory mode has the characteristics of straight foot trajectory,small fluctuation and long stride distance,so that the multi-legged robot has better walking performance on the flat grass,cement-stabilized crushed stone road and other structural roads,so as to realize the practical application requirements of improving the speed,efficiency and mobility of the foot carrier.