Study Of Motor Pre-tighting Active Seat Belt

At present,automobiles have become an indispensable means of transportation for people's daily travel,and their safety performance is constantly improving.The car safety system is an important guarantee for the personal safety of the occupants,mainly including active safety systems and passive safety systems.As an important part of the safety system,the seat belt usually binds the occupant to the seat in the event of an accident,preventing the occupant from flying out of the vehicle body.Most domestic passenger cars now use gunpowder-type seat belts.These belts will only tighten when a collision occurs.When the danger is sudden,the occupants cannot be effectively restrained in time to correct the occupant's sitting posture,and the occupants may be blasted by the airbag.Secondary damage,and gunpowder explosion is also destructive and irreversible,and is a passive safety system.Active seat belts are developed to improve the safety of vehicle occupants,and at the same time comply with the development trend of active safety technology,which can effectively reduce the occurrence of traffic accidents.This paper analyzes and summarizes the research work of relevant domestic and foreign institutions on car seat belts.Based on the existing gunpowder type seat belt structure,the gear pre-tensioning device is designed by using the gear transmission mechanism,and the control unit is connected to the control unit according to the vehicle data signal.Adapt to adjust the status of the seat belt,realize the early warning and pre-tightening function,suitable for occupants of different sizes.The main contents are as follows:(1)The mechanical structure of the retractor of the key component of the seat belt is mainly designed.Includes assemblies for motors,controllers,transmissions,clutches,and sensitive mechanisms.It enables the function of motor-driven webbing to be retracted;(2)Motor control hardware circuit module design.The control system is developed based on the 16-bit MC9S12XS128 MCU developed by Freescale.The core system minimum circuit,power supply circuit,CAN module peripheral circuit,motor drive circuit and other circuit modules are designed.The software system program includes main program,interrupt program,control program,etc.The control algorithm of the motor uses PID fuzzy control algorithm.The combination of mechanical design and control enables the enhancement of active safety requirements to meet the functional definition of active seat belts.This project completed the research of the prototype of the active seat belt by designing the structure of the motor pre-tightening active belt retractor,building the motor model and selecting the controller.It has been used as a reserve technology and a company.The prototype of a generation of products.