| Driverless roller is an important technical means to improve the construction quality,efficiency and safety of hydropower station,and ensure the health of construction personnel.In order to ensure the safety and effectiveness of these driverless vehicles,a wide range of tests must be carried out.However,the test of driverless real vehicles is not cost-effective,low efficient,and there are some risks lie on it.This paper develops a system based on roller hardware in the loop simulation platform to solve the above problems.The research is as follows:1)First,in order to reflect the dynamic characteristics of multi-body and multi degree of freedom of the roller and make sure it can be used as the controlled object,a7 degree of freedom dynamic model of the roller was established.Firstly,in view of the understanding of the structure and function of the vibration roller and the requirements of the realization of the automation work.An idealized assumption was made before modeling,which simplifies the vehicle to 7 degrees of freedom object.Then,by defining three local coordinate systems and one global coordinate system,the position expression of the front and rear body centroids in the global coordinate system was determined,and then the total kinetic energy and potential energy of the whole vehicle were calculated.Finally,seven generalized forces calculated by using the virtual principle,and 7 Lagrangian equations,then seven degrees of freedom can be solved.In the generalized force,the latitude and longitudinal forces of the road to the tire and the vibrating wheel calculated by the Gim tire theory with the deformation of the tire and the road as the research points respectively.The dynamic model was verified on the flat road.According to the statistics,the maximum value of the difference about the heading angle and the heading angle velocity calculated between the real vehicle and the model are 6.3deg and 4.4deg/s respectively,and the maximum value of the difference about the longitude and lateral position are 0.534m and 1.575m respectively.2)In order to save the cost of real vehicle test,reduce the risk and improve the efficiency of the test,the key model of hardware in the loop simulation platform of intelligent vibration roller based on d SPACE is developed.The vehicle and road model,obstacle case model and case scheduling model are developed.Among them,the high-precision space kinematics model of vehicles mainly includes plane kinematics module of vehicle,road module and vehicle-road coupling module.The road module was analyzed from two aspects of road material composition and road undulation,which was simplified to 13 parameter variables to describe the road.The vehicle-road coupling module uses multiple first-order polynomials to fit the mapping relationship between the road and the vehicle state according to the working principle of the roller and the real vehicle test data,and the real vehicle data was used to calibrate the model.The results show that the developed high-precision space kinematics model of vehicle can be used to verify the robustness of the control algorithm.Finally,by testing the tracking,staggering distance,speed and obstacle avoidance functions of the controller under unstructured and flat road conditions,the practicability of the developed vehicle and road model,obstacle case model and case scheduling model were verified.By comparing the results of tracking curve between HIL and real vehicle test,the maximum absolute values of distance error,angle error and curvature error of tracking curve are 0.088m,0.118rad and 0.042m-1 respectively.When the real vehicle test is in complex dam surface environment these errors are 0.037m,0.157rad and 0.051m-1 respectively.The difference between the two test platforms is small,which shows that the developed hardware in the loop simulation platform of driverless roller has high simulation characteristics. |
