Structural Design And Motion Characteristics Analysis Of Wheel-track-leg Robot For Post-disaster Rescue

In recent years,major natural disasters such as earthquakes and landslides have occurred in many regions of China.Faced with the frequent occurrence of major natural disasters,the research on post disaster rescue equipment has received increasing attention from the country.When natural disasters occur,timely adoption of post disaster rescue measures can protect people’s lives and property in a timely manner.However,in the face of a post disaster environment where collapse or occupation may occur at any time,hasty entry by search and rescue personnel may threaten the safety of rescue personnel.Therefore,rescue robots are usually used to replace search and rescue personnel in dangerous areas for tasks such as search and exploration,thereby effectively reducing the casualties of rescue personnel.Nowadays,most of the robots used in rescue missions are composite robots,which mainly adopt configurations such as wheeltrack,track-legged,and wheel-leg.These types of robots have a single movement mode,slow travel speed,poor flexibility,and complex structure,making it difficult to flexibly adapt to complex environments.It can be seen that studying a composite robot that can flexibly adapt to complex environments and has multiple motion modes is of great significance.This article designs a wheel-track-leg robot that combines multiple motion modes of wheels,tracks,and legs to address this situation.The topic of this paper is from the national key research and development plan "Development of Wheel-track-leg Autonomous Unmanned Vehicle"(project number:2020YFC1511703).This paper takes the wheel-track-leg robot as the research object,and conducts structural design and motion characteristics analysis of the wheel-track-leg robot.Specifically,it includes the overall design,detailed structural design,motion mode analysis,motion characteristics analysis,dynamic simulation,structural optimization,and prototype testing of the wheel-track-leg robot.The main research content is as follows:Firstly,the overall design of the wheel-track-leg robot is carried out with the wheel-track-leg robot as the research object.The characteristics of the post-disaster environment and work task requirements were analyzed,and the basic functional requirements and performance indicators of the wheel-track-leg robot were determined.Aiming at the problem of wheel-track-leg robot configuration selection,this paper proposes three wheel-track-leg robot configurations according to the different wheel matching methods,and after comparing the advantages and disadvantages of the three configurations,the configuration scheme of wheel and crawler coaxial is selected.Considering the installation and drive requirements of each module,the overall layout of the robot is divided into two layers,and the swing arm drive scheme and the wheel and crawler drive scheme are all driven independently by 4 motors.Secondly,based on the overall design of the wheel-track-leg robot,a detailed structural design and circuit design of the robot’s transmission mechanism,swing arm mechanism,frame and battery bracket are carried out,and the structural parameters of each part of the robot are determined to provide a numerical basis for the analysis and calculation of motion characteristics.Based on the characteristics of the motion of a wheel-trackleg robot,analyze the characteristics and application scenarios of seven motion modes of the robot:"wheel,track,leg,wheel-leg,wheel-track,track-leg,and wheel-track-leg".Thirdly,with the aim of selecting a suitable motor,establish a climbing,self-supporting,and turning motion model for the wheel-trackleg robot,analyze the force on the robot,and obtain the required driving torque for the wheel-track-leg robot under different working conditions.And establish a wheel-track-leg robot track model and road surface in Recurdyn software,and conduct dynamic simulation of the robot’s climbing,self supporting,turning,and post disaster simulation environment to verify the correctness of the motion characteristics analysis results.Based on the results of dynamic simulation and analysis of motion characteristics,select the motor and reducer models required for robot driving.Finally,in order to ensure good maneuverability and stability of the robot under light weight,Ansys Workbench software was used to optimize the steel parts of the robot.After optimization,the weight of the drive motor support was reduced by 50%,the weight of the swing arm motor support was reduced by 20%,and the weight of the left and right vehicle frame connection plates was reduced by 20%.In order to further verify the motion ability of the wheel-track-leg robot,after completing the development of the physical prototype,experiments were conducted on the prototype for climbing,loading,turning,self-supporting,crossing ravines,and climbing stairs.The test results showed that the robot’s structure was stable and its motion performance met the design requirements.