Research On Obstacle Crossing Ability Of Wheel-Leg Unmanned Transportation Platform

In many cases,the unmanned transportation platform needs to overcome many kinds of unstructured terrain.It is difficult for the ordinary platform to work well in these conditions.The wheel-leg transportation platform has the advantages of wheel platform and leg platform,so it can be used in many fields.At present,there are few related researches on vertical obstacle crossing of wheel-leg unmanned platform.According to the needs of the project and the development of new technologies,this article takes the wheel-leg unmanned delivery platform as the research object.This article completes the overall design of the platform,analyzes the platform's vertical obstacle-crossing process,and proposes a control strategy for the platform's vertical obstacle-crossing.The main research contents and results are as follows:(1)The current research situation of unmanned platform and obstacle-crossing theory are analyzed.The single-mobile and compound mobile unmanned obstaclecrossing platforms are analyzed,focus on comparative and analysis of typical wheellegged unmanned platform.The existing theoretical research results and research methods of obstacle-crossing are analyzed.(2)The overall design of the wheel-legged unmanned delivery platform is carried out.First of all,the different types of wheel-leg are compared and analyzed to determine the design of the single swing leg-wheel.Then determine the platform's external dimensions,center of gravity,wheelbase and other parameters,determine the swing leg actuator,complete the wheel hub motor matching calculation.(3)The theoretical models of the platform's vertical obstacle crossing process are established and the platform's vertical obstacle crossing capability is analyzed.Firstly,the mathematical models of the platform's vertical obstacle crossing process in active mode and passive mode are established.Then the numerical calculation method is used to analyze the influence of platform swing leg parameters,center of gravity position,ground attachment status and wheel driving force on platform obstacle-crossing capability in active mode.(4)The control strategy of the platform for vertical obstacle crossing conditions is determined.According to the vertical obstacle conditions,two styles of leg swing control strategies are proposed.Aiming at the driving wheel control in the process of obstacle crossing,an sliding mode control algorithm is proposed.(5)The obstacle simulation analysis and functional test verification of unmanned transportation platform were carried.The Adams-Matlab co-simulation model was built,and the simulation analysis of two obstacle-crossing control strategies in safe mode and fast mode was carried out for the different conditions,and the obstaclecrossing control strategy and the driving anti-skid control strategy were verified.The overall scheme of wheel-leg unmanned vehicle,the analysis method of vertical obstacle crossing capability and the strategy of vertical obstacle crossing control have certain theoretical value and reference significance for the research and application of unmanned vehicle platform.