| With the progress of science and technology and the development of industrialization,mobile robots are widely used in rescue,military reconnaissance,security inspection and other fields.The spherical robot has the advantages of high reliability and low energy consumption.Therefore,how to break through its single motion mode,improve its terrain adaptability,and enhance its cooperation ability with other types of mobile robots has become the focus of research on spherical robots in recent years.In this paper,the spherical robot as the research object,with low weight,small volume,multi-form,high mobility,strong obstacle jumping ability as the design index,proposed three kinds of spherical robot concept scheme configurations capable of multi-mode motion,through the dynamics theory calculation,Solidworks three-dimensional modeling and Adams dynamics simulation,A configuration scheme conforming to the design objective was selected by analysis,and its detailed structural design was carried out.On this basis,the experimental prototype machining,physical testing evaluation and prototype improvement and optimization were carried out.The main contents of this paper are as follows:(1)Analyze and compare the structural designs of different spherical robots at home and abroad,determine the concept scheme of spherical robot which takes double hemispherical wheel drive as the main driving mode and uses deformable hemispherical wheel mechanism to improve the obstacle-crossing performance,and give the design index of spherical robot.On this basis,three kinds of deformable three-blade deployment configurations of hemispherical wheels,including planetary gear train,passive gear and ratchet pawl mechanism,were proposed.(2)The scheme analysis of the three configurations was carried out with the mechanism theory,and the radial deformation expansion ratio of the three configurations was summarized.The kinematic parameters of the spherical robot in different motion modes are obtained by calculating the motion state equation and motor torque.Using Solidworks,the simplified three-dimensional models of different shape prototypes and three typical terrain models of flat land,slope and vertical obstacle were established.The dynamics simulation of virtual prototype was carried out by Adams,and the time-displacement and time-torque curves of spherical robot under different working conditions were obtained.Through the comparison and analysis of the simulation results and the mechanical characteristics of the three configurations,the design scheme of the spherical robot with the ratchet pawl mechanism three-blade expansion configuration as the deformable hemisphere wheel is determined.(3)The deformable hemisphere wheel system,axial deployment system and frame structure of the spherical robot are designed and modeled in detail,and the deformation mode of the radial expansion of the hemisphere wheel triggered by the displacement of the axial deployment system is determined.On this basis,two kinds of motion modes and control systems of spherical robot are designed,and the driving motor,controller,sensor and other hardware are selected.After finishing the machining and assembling of the test prototype,the test prototype was tested.The feasibility of the expansion deformation principle of the spherical robot in this design and the motion feasibility of the hemisphere wheel based on the ratchet pawl mechanism three-blade expansion configuration are verified.(4)The test results of the test prototype were analyzed,and the structural design of the deformable hemisphere wheel and axial deployable mechanism of the spherical robot was optimized and improved,which solved the problem of excessive friction between some parts in the design leading to the lag in the process of deployable deformation.On this basis,the strength check of key parts such as the spindle was completed,the final design scheme of the spherical robot was determined,and the prototype was tested.The experimental results show that the design scheme of the multi-form spherical robot can adapt to a variety of complex unstructured terrain,and has strong obstacle surfacing ability,which conforms to the design objectives of this paper,and provides a reliable design idea and technical scheme for the study of the comprehensive performance of the spherical robot. |
