We have developed a dynamic model for the test vehicle based on a two-track model.
For the development and commissioning of traditional vehicles, this model has great significance for the parameterization and the parallel development in the initial stage of vehicle development. At the beginning of vehicle development, when the prototype vehicle has not been developed, the engineer can use the high-fidelity vehicle dynamics model :
1) to parameterize the vehicle and predict the influence of kinetic parameters and vehicle geometry parameters on vehicle dynamics. Therefore, the potential dynamic problems and irrationality of the designed vehicle are discovered in time;
2) In the earlier vehicle development stage, the other system components of the vehicle are developed in parallel. Based on the vehicle dynamics simulated by vehicle dynamic model, some systems based on vehicle dynamic behaviors, can be developed without a real prototype. After the prototype vehicle is produced, it is only necessary to make some fine-tuning of the performance of the real vehicle. Such a parallel development process saves the development time and cost of the automobile manufacturer compared to the traditional development procedure.
In the development and validation of automated driving systems, in addition to the advantages above, the model can be integrated into Simulation-based Validation Environment (for example, PilotD's GiaA system) to exploring the influence of dynamic behavior on the detection and measurement, as well as the plausibility of the system's response to vehicle dynamics limits.
Through this model, the rotation, displacement, force and torque of the four wheels and the body of the vehicle under test on each coordinate axis can be calculated. On the one hand, the environment perception sensors (such as radar, lidar, camera, etc.) are fixed on the vehicle body, and the results of the detection mostly reflect the relative relationship between the vehicle and other objects (for example: relative speed, relative Distance, relative angle, etc.). The instability of the dynamic behavior of the vehicle will also greatly affect the quality of the detection and subsequent environment comprehension based on the detection. Therefore, in the design of the automated driving system and the subsequent hardware and software in-loop testing, the accuracy of vehicle dynamic behavior simulation also has a decisive influence on the operation quality and efficiency of the automated driving system. This has become one of the reasons why this model is indispensable in the simulation of automated driving simulation.
On the other hand, in addition to detecting the sensing system, the automated driving system also includes the behavior decision system and the underlying control system. The decision/control quality of these two parts is closely related to the dynamic characteristics of the vehicle. For example, if a car’s braking distance is relatively long, the behavior needed by it should be earlier decided.
HiFi Vehicle Dynamic Model: 1.The vehicle model must include a high-fidelity dynamic model that can truly represent each important physical quantity in vehicle dynamics.
2.However, the vehicle dynamics model must be simple enough that simulation-based test validation can still be performed efficiently.
3.Therefore, we developed a vehicle dynamic model based on a realistic two-track model without affecting simulation efficiency.
4.The user can know the specific calculation method of the force and torque carried on the various parts such as the body and the tire. In the case of complex applications, the user can modify it accordingly; or when validation, the error is found, it is easier for users to find out the cause of the specific problem: if it is due to problems in system design? or a simulation error?