A Headlight Automatic Leveling System with Misadjustment Suppression

The Automatic Leveling System(ALS) is a new adaptive control technique which is applied to vehicle headlights to provide better driving experience at night. By the control of ALS, the integrated stepping motors can adjust the pitch angle of headlight and maintain a stable illumination distance when driving. According to the values of the hall sensors on chassis, the real-time beam angle of headlight can be obtained. However, there are lots of interference coming from the vehicle mechanical and electric system, which may lead to stepping motor misadjustments. To suppress these unexpected motor moves, a smoothing filter integrated ALS is proposed in this paper, which is realized on a S32Klxx series MCU platform. The smoothing filter is introduced to eliminate unexpected sharp interference coming from the hall sensors, and therefore enhance the smoothness of stepping motor output. To ensure the system stability and real-time performance, the CAN/LIN buses are used to communicate between MCU and headlights. The ALS proposed in this paper can be further used in the automotive front light systems.