Study And Realization Of Steering Force Feedback For Driving Simulators

With the development of computer vision technologies, sensor technologies, processor technologies and moving platforms, driving simulator technologies are becoming more and more advanced, and are being applied in a variety of vehicle road tests. In order to make driving simulators simulate the vehicle motion with more fidelity, and satisfy the requirements of conducting every kind of road test, the development of new vehicle products and the research of human-vehicle-road closed loop system, the study of driving simulators is still the research focus of many research institutions all over the world.The simulation of steering feel is a key research part of the research of driving simulators, since the simulation effects of steering feel directly influence drivers’ sense of immersion when driving a driving simulator, and finally influence the accuracy of drivers’ operation. The steering torque feedback with enough fidelity enables road tests to be more realistic, so that the test data from it will be more trustful. For the purpose of realizing realistic steering feel, the first thing to do is to establish a steering torque feedback model with steering feel of a real vehicle, and the second thing to do is to set up a steering simulation platform with the ability of the realization of the communication among all pieces of equipment and the realization of real-time simulation of steering feel. Combined with the program of the development of the driving simulator between my laboratory and the SAIC Motor Company, this research mainly focuses on in-depth research for the simulation of steering feel with enough fidelity of the driving simulator. The major tasks of this paper are studying the steering feel of a real vehicle and simulating this steering feel on the steering wheel of the driving simulator. They can be described in detail as follows:(1) Establishment of the steering torque feedback modelSince electric power steering(EPS) systems are commonly mounted in current vehicles, this paper determines EPS systems as the modeling object. Through the analysis of the components of steering torque on the steering wheel of EPS systems, this paper sets up the steering torque feedback model of EPS systems. The range of real vehicles’ parameters is chosen as model parameters’ range.(2) Sensitivity analysis between model parameters and steering feel propertiesThe major utility of driving simulators is to simulate real vehicles’ characteristics, thus the key purpose of the steering wheel on driving simulators is to simulate the steering feel of a real vehicle. However, due to the nonlinearity of the steering torque feedback model, it is difficult to create artificial steering feel(came from the model) that matches the steering feel of a real vehicle in every aspect solely through tuning model parameters. As a result, sensitivity analysis between model parameters and steering feel properties has to be conducted in order to determine the impact effects and impact levels of model parameters on steering feel properties. And then theoretical guidelines based on the analysis results can be proposed to guide the tuning of the steering feel, finally the steering feel of a real vehicle can be “copied” as much as possible. Therefore, this paper focuses on the determination of evaluation measurements, of the value range of model parameters and of the DOE(Design of Experiment) method, and conducting sensitivity analysis on the basis of Isight software.(3) Study of the model steering feel “copying” the real vehicle’s steering feelThat the model steering feel copies the real vehicle’s steering feel can be seen as the optimization of the model steering feel. This paper optimizes the model parameters on the basis of the steering feel properties for the purpose of simulating real vehicles’ steering feel. The steering feel properties of the SUV are chosen as the optimization targets. And based on the sensitivity analysis results, the model parameters that influence steering feel properties notably are decided to be optimization parameters, and whose real value ranges are selected as the constraint conditions. As for the coupling effects between model parameters and steering feel properties, this paper firstly determines the significance level of every steering feel property based on the subjective evaluation results. On the basis of the significance level, the weight factor of every steering feel property and the optimization function are determined. Finally, optimization computing is conducted in Isight software and the optimal solution is inputted to the co-simulation model to examine if the errors are acceptable. Then the optimized solutions are chosen as model parameters. The decided steering torque feedback model is cosimulated with the vehicle dynamic model from Car Sim in Matlab/Simulink, and then the simulation results are compared with the road test results of the SUV in order to verify the fidelity of the model.(4) Building of the steering simulation system and study of the motor current control algorithmThe final goal of this paper is to simulate real vehicles’ steering feel on the steering wheel of driving simulators, therefore the final work is to set up the steering simulation system and to study the steering torque motor current control algorithm.First of all, in order to realize the function of the steering simulation system, the architecture of the system, the workflow of the system, the mechanical structure of main parts, the operating desk, the hardware and the software are designed. Secondly, the components of resisting torque of the system are analyzed and the optimization algorithm is selected to identify these components. In the end, the fuzzy incremental PID algorithm is presented to control motor current, and current compensation control algorithm is put in the framework of motor current control based on the identification results.