Research And Realization Of Anti-pinch Control Method For Automobile Electric Tailgate

With the rapid development of automotive technology,the intelligentization of automobiles is gradually arriving.In the development trend for the future of automobile intelligence,technologies such as driverless,artificial intelligence and vehicle interconnection communication may become one of the core competitiveness of smart cars.Among many automotive intelligent technologies,automobile tailgate anti-pinch technology,as a technology to improve vehicle safety,is used more and more widely in various types of passenger vehicles.In some foreign countries,the tailgate anti-pinch technology for automobiles has already came into being,and also the corresponding tailgate anti-clamping standard.However,due to the late start in China,the research on anti-pinch technology is limited on automobile windows.According to a data compiled by the Associated Press,since the 20 th century,there have been more than 500 cases of children who have been treated for tailgate injuries each year.There are also cases of car window injuries in China.Therefore,in view of the automobile users’ safety,it is imperative to study the automobile tailgate anti-pinch technology.This paper proposes an automatic anti-clamping method for the tailgate of a car.Firstly,we use the current sensor to collect,detect and filter the current signal of the tailgate pusher motor.Secondly,the anti-pinch force control algorithm is used for pressure judgment.Then with the control device,we are able to control the movement of the tailgate pusher motor,which at last realizes automatic anti-pinch control of the electric tailgate.The paper studies the working principle of the electric tailgate electromechanical system in the first place,and establishes the electromagnetic and dynamic equations of the system.On this basis,the simulation model of the system is built by Matlab,and the validity of the model is verified by experimental data.On the next,the paper studies the method of estimating the electric tailgate clamping force.On the basis of the foreign estimation method of window clamping force,an anti-pinch force method based on the slope of the current signal of the push rod motor is proposed.And the effectiveness of the method is verified by the simulation model.In order to solve the problem that the slope estimation method may misjudge the clamping force because of signal disturbance,the study further proposes the integral estimation method combined with Kalman filtering.The simulation of the method is carried out.The two methods show that the Kalman filter-based integration method can better deal with the current signal interfered by external noise and improve the accuracy of tailgate clamping judgment.As to the implementation of the above anti-pinch control method,the hardware and software design of the controller is one of the key issues.In this paper,the initial hardware and software design of the system controller is carried out for the requirements of the electric tailgate anti-pinch control system.The software is modularized,including initialization module,button monitoring module,anti-pinch algorithm module,voltage monitoring module,etc.The hardware is designed on the principle of miniaturization,integration and low cost,and for the main control chip,the 32-bit microcontroller STM32F103C8T6 made by ST company which adopts the ARM Cortex-M core is used as its driving core.The whole hardware system contains signal acquisition module,A/D conversion module,driver module,etc.Finally,the experimental tailstock structure is built to simulate the rear door structure of the car,and the control of the gantry is realized by a simplified controller.The bench test firstly tests the performance of the bench,and then tests the two anti-pinch control methods.The experimental results verifies the effectiveness of the two methods.At the end of the paper,the optimization ideas of the future tailgate anti-pinch control method are discussed.