Research And Development Of Automotive Adaptive Front-lighting Systems

With the development of automotive electronic technology,more and more kinds of traffic safety function have been introduced to modern car configuration.Adaptive Front-lighting Systems is an active safety system.Focusing on the problem that the vehicle lighting and its body direction has a certain angle in the process of vehicle turning,thus it can't illuminate the front area very well.The study developed the AFS,including hardware and software.The software part involves sensor signal acquisition and processing,the master-slave communication between the main control module and slave module,stepper motor drive control and etc..The hardware involves the Master and Slave circuit module design,the connection between the sensors and Master module,the connection between the stepper motors and Slave module and etc..First of all,the paper studies the domestic and foreign research status of automotive AFS technology from the aspects of system architecture,sensor selection and control methods;On this basis,to build the system hardware platform,including the AFS main control module is used to collect signals of the suspension height,steering wheel angle,GPS module,for receiving commands from the host control module,motor control module is used to control the stepper motor,and through the Hall sensor to ensure the precision of the motors;Based on the hardware platform,this paper developed corresponding software control algorithm.The AFS Master module acquire the sensor signal and the signal after handling is used to horizontal direction and vertical direction light angle calculation.The AFS Master module send control instructions to the Slave module via LIN(Local Interconnect Network)bus.After receiving commands from the LIN bus,the Slave module compared motor position requirements with the actual motor position,then determine the number of step motor needs to be adjusted and let the motor control module control the stepper motor operation;Then,the motor driven auxiliary module is used to receive control command from the main control module and the drive stepper motor operation.Again,the development of control software can realize the adaptive adjustment of light type,the software based on the sensor signal and automatically adjust the speed,the front left and right,pitching light rotation,adjust light type,to respond to the needs of different road traffic;Finally,the experimental prototype of the AFS system is developed,and the experimental verification is carried out the speed from 0 to120km/h and different light mode;The experimental results show that AFS could achieve the curve with steering and ramp pitch adjusting and complete the light configuration.The light type could meet the requirements of adaptive front lighting system under different speeds,like intersection,village,city and high speed.The deflection angle of the horizontal headlight system range is 7.5 degrees inward and 15 degrees outward,the horizontal error is ±0.8 degrees,the vertical direction range is3 degrees upward,3 degrees downward,and the vertical error is about ±0.2 degrees.