Design And Research On Comprehensive Performance Test Platform For Wheel And Legged Robot

Wheel is one of the most important parts of vehicle,which affects the vehicle's mobile performance and terrain adaptation.The structural parameters of wheels are more important when passing obstacle.The lunar rover needs to have a good ability to cross obstacles to adapt to the soft lunar soil covered by the lunar surface.For extremely complex terrain,the legged robot has the advantage of high flexibility.The open chain legged mechanism with more degrees of freedom is capable to suit complex terrain,and it is of great variety.For the wheel and legged mechanism movement and obstacles and other requirements,a comprehensive performance test platform of wheel-ground interaction test system and run-jump test system of legged robot under different working conditions is proposed.First,the overall design of the test platform is completed.Three schemes are proposed and compared to determine the wheel data measurement method,the overall system layout and mode switching.By comparing and analyzing the theoretical results of Bekker model and Wong-Reece model in Matlab,the ground mechanics data of different wheel sizes under different models were obtained,which provides a basis for the selection of driving system and the strength design of mechanical structure.A kind of 1-DOF closed chain mechanism with eight bars and ten pairs is constructed to assist the legged robot to jump.The length parameters of the mechanism are optimized to minimize the trajectory error in the vertical direction during the passive movement of the mechanism and to better simulate the state of test leg's vertical bouncing.Secondly,the rigid body dynamics model of the test platform is established based on ADAMS,and the contact mechanics model between lunar soil and mechanical structure is established based on EDEM.The contact dynamics model of the wheel soil is established by the co-simulation of ADAMS and EDEM.The simulations are carried out under four conditions: contact of wheel with hard surface under ground gravity and lunar gravity and contact of wheel with lunar soil at full slip and at zero slip under earth gravity,and then the results are compared with the theoretical calculation and verified.The jumping simulation under the maximum load and maximum jumping height of the tested leg is completed,and impact force data of swinging cantilever are obtained,which provides a basis for the engineering design.Then,based on the overall design plan of the test platform,the calculation parameters of ground mechanics and simulation results of the two modes,The engineering design of single wheel test system,single leg test system,central rotation and lifting system and soil bin system is completed.Besides mechanical design and selection of drive system,the mechanical aspects of finite element analysis and strength check are completed.Finally,based on the mechanical design and simulation results,the type selection and signal output mode of torque sensor,three-dimensional force sensor,range sensor and inclination sensor are determined.Power cord arrangement and industrial computer data collection and summary are completed.Test scheme of continuous slip rate and fixed slip rate is formulated and the design of test platform's measurement and control system is completed.