Research And System Design Of Anti-Pinch Control Strategy For Automobile Window Based On Double Hall Sensor

With the development of automotive electronics technology,the automotive industry has proposed the concept of human-car interaction,artificial intelligence and unmanned driving,automotive intelligent operation has become a hot research.when the window grip the obstacle in the rising process,especially when caught in children.The window anti-pinch system can detect the danger and control the window to fall.Power window anti-pinch system in this context came into being,demand for this system increased year by year.However,due to anti-pinch algorithm and control strategy design flaws,At present,the domestic anti-pinch system's sensitivity,durability,and reliability was poor.It can be seen,the application and development of window anti-folder module have important practical significance and development prospect for promoting the development of China's automobile industry.In this paper,the power window structure was analyzed,and then the principle of window circuit control was studied.Compared with the three kinds of anti-clip program,the current ripple detection method require high current quality and low durability.The detection method of the hall position sensor and the motor current threshold needs to design the window running state recognition circuit,and program was complicatedt.The robustness of external magnetic interference based on the algorithm of hall sensor pulse period change was poor,and if the pulse signal was disturbed,it will lead to the failure of the anti-folder system.After the study of hall sensors,a dual-hall sensor based on switch-type and latch-type combination was proposed for window position detection.This particular dual-hall sensor combination can recognize motor steering without external circuit support.The window-load model was established,and the method of wavelet filtering to current noise reduction was proposed.Using different wavelet function analysis the motor current of the model.Simulation results show that different wavelet groups can denoise the current signal and identify the obstacle,improve the reliability of the system.Through the simulation of the motor to impose different loads,the results show that the motor current can directly determine the motor running state.Therefore,the paper uses the motor current threshold method to monitor whether the window was clamped to the obstacle.This paper discusses the anti-pinch control strategy of double-hall sensor for position detection and motor current threshold for obstacle recognition.According to the anti-folder control flow chart,the window anti-pinch model was established in Stateflow.the Hall pulse signal generator was also designed.Simulation verified double-hall sensor can calculate the window position in this simulation model.When the motor current exceeds a specific threshold,the window was lowered and anti-pinch measures are taken.Finally,using StateflowCoder to generate the standard C language code of the Stateflow model flow chart.On the basis of the principle of window control,minimum processing system was built with Freescale MC9S08AW60 chip.Next,the motor drive circuit,current detection module and hall sensor detection module are all designed.The experimental results show that: the double-hall sensor and the current threshold anti-pinch strategy are reliable and can achieve the expected effect.