Research On Ultrasonic-Radar-in-the-Loop Test Method For Automatic Parking System

The automatic parking system can control the vehicle to automatically find the parking space and complete the parking,which can effectively reduce the driving pressure of the driver.However,the automatic parking system has the characteristics of high complexity of the test process and inexhaustible test scenarios,which makes the traditional site test difficult to meet the test requirements of the automatic parking system.Therefore,a convenient and efficient automatic parking system test method needs to be studied urgently.Supported on the National Key R&D Program of China(2022YFB2503402),this paper has built an ultrasonic-radar-in-the-loop test platform,and based on this,a virtual test scene is built to conduct hardware-in-the-loop test on the automatic parking system based on the ultrasonic radar to perform environmental awareness tasks.Firstly,the digital model of ultrasonic radar considering the influence of atmospheric conditions is established and the ultrasonic-radar-in-the-loop test platform is constructed,then an accelerated test scenario generation method based on Bayesian optimization principle is proposed.Finally,based on the ultrasonic-radar-in-the-loop test platform,the automatic test of the automatic parking system is carried out.The specific research contents of this paper are as follows:(1)Ultrasonic radar modelingQuantify various energy losses in the process of ultrasonic propagation in a given scenario,establish the functional relationship between atmospheric conditions and the detection range of ultrasonic radar,calibrate the unknown parameters in the function,and then deduce the detection range of ultrasonic radar;A method to obtain the true distance value of the target in the virtual simulation environment is proposed,and the true sound velocity under the given atmospheric conditions is solved.The true distance value is de-idealized and corrected to the actual detection distance value of the ultrasonic radar.Finally,the ultrasonic radar model is verified by the real vehicle.(2)Construction of ultrasonic-radar-in-the-loop test platformDesign the overall architecture of the ultrasonic-radar-in-the-loop test platform,and determine the closed-loop interaction logic of the ultrasonic radar model,the ultrasonic radar hardware,the ultrasonic echo simulator,the virtual simulation scene,the vehicle dynamics model,the tested automatic parking algorithm and other test components;The software system of the test platform is built by Car Sim,MATLAB/Simulink,Pre Scan and other software;The hardware system of the test platform is built by using hardware components such as Park Pilot URF6 ultrasonic radar,PC,ultrasonic echo simulator,PXIe-8880 embedded controller,and the data communication between hardware components is completed based on UDP(User Datagram Protocol)and CAN(Controller Area Network);Finally,in order to improve test efficiency and save labor costs,an automated test method for the test platform is proposed.(3)Research on test scenario generation method for automatic parking systemDefine functional scenarios based on the hierarchical model proposed by PEGASUS project and the test requirements of the automatic parking system;Extract the functional scenario keywords and map them to the corresponding scenario parameters,determine the components of the logical scenario according to the internal relationship of each scenario parameter,determine the parameter space of each scenario element according to the relevant domestic and foreign test laws and regulations,constitute the logical scenario;In order to improve the test efficiency,the specific scene generation problem is modeled as a high-dimensional nonlinear optimization problem with the degree of danger in the parking process as the objective function,and solved by Bayesian optimization method to realize the accelerated generation of automatic parking test scenarios(4)Test and verificationThe automatic parking system and test scenario generation method are tested and analyzed based on the ultrasonic-radar-in-the-loop test platform.The hardware-in-theloop test and software-only simulation test of the automatic parking system are carried out by using the randomly generated test scenarios.The comparison of the test results of the two shows the advantages of the hardware-in-the-loop test platform of the ultrasonic radar;Based on the hardware-in-the-loop test platform,the optimization test and combination test of the automatic parking system are carried out respectively,and the set of dangerous scenes of the automatic parking system was obtained.The test results showed that compared with the combined test,the optimization test improved the generation efficiency of dangerous scenes in parallel parking conditions and vertical parking conditions to 2.2 times and 4.9 times respectively,on the premise that the coverage of the generated dangerous scenes was higher than 85%.