Study On Vehicle LED Advanced Headlamp Illumination Theory Based On Infinitesimal Energy Mapping

Vehicle active safety is an important method to reduce road accident rate. LEDAdaptive Front-Lighting System (LEDAFS) is one of the key research projects in road andvehicle active safety.LEDAFS includes illumination system and control system. The main feature ofLEDAFS is that the illumination beam can adjust with the condition of the vehicle body, tomeet the appropriate illumination in different environment, which can enhance drivingsafety performance at night. However, in illumination, the common design method ofLEDAFS is a filament image method, which adjust the main curve of the surface byexperience to generate the dipped beam pattern. The rate of luminous energy is low becauseof that the transmission and distribution of the luminous energy is not considered in thismethod. For control system, the identifiability real-time, response speed real-time, controlaccuracy and stability of LEDAFS control system are not efficient. Therefore, a designmethod of energy conservation and safety illuminative system based on infinitesimalenergy mapping is proposed in this paper.Firstly, according to the non-image optics and the feature of regulation dipped beampattern, aimed at the iterative deviation angle generated in the iteration can lead to highdeviation between the design anticipation and the result, LED energy conservationillumination principle based on infinitesimal energy mapping is discussed. The designprinciple which is on the basis of the mapping between light source energy mesh and thetarget pattern mesh, made a spherical iteration rule which can iterate surface point. Thespherical iteration rule on the condition that normal vector is the same with the refractionvector calculated by Snell’s law, can reduce configuration error. Thus, energy diffusion ofthe iterative deviation angle can be hold-up, and the system can make the energydistribution accurately.According to the regulation pattern stipulated by ECE123, fourillumination modules are needed to generate multiple patterns by superposition. To ensurethe high rate of luminous energy, a direct projection structure is proposed. And the designmethod of the lens in this structure is also proposed based on the prinple of infinitesimalenergy mapping. The illumination patterns of the other illumination modules are rectangle of different area. For these modules, a total inner refractor design method is also proposedbased on infinitesimal energy mapping. At the end, the four illumination modules aredesigned by these method, and simulated in Tracepro.After that, a predictive control method based on the predictive model is proposed. Ineach sampling period, the prediction value can be accord with real-time, which can ensurethe instantaneity and robustness of the whole control system. The LEDAFS steering gearsare designed and calculated by the moment transfer rule and ratio of revolution of gears insteering. A simulation model is also established in Simulink, the result compared with servocontrol, which verified the feasibility of this method.Finally, based on these power modules, an experiment bench of illumination system isestablished. Taking advantage of this experiment bench, the feasibility of the infinitesimalenergy mapping is verified. Then, an experiment bench of control system is also established.Making use of this bench, the feasibility of the prediction model is verified.