基于增量式比例-积分-微分控制和脉冲宽度调制的车辆舱内超压测控系统设计

Design of Vehicle Cabin Overpressure Measurement and Control System Based on Incremental Proportional-Integral-Derivative Control and Pulse Width Modulation

为有效防止危险化学环境的有害气体从车辆舱体缝隙进入舱内,采用驱动风机加入净化空气建立舱内超压的方法,设计基于STM32单片机的车辆舱内超压测控系统。系统采用MQ135气敏传感器为例,采集有害气体(一氧化碳等)信息作为STM32控制器的触发信号,气压传感器采集舱内外压强得到压强差,运用增量式PID算法输出PWM波实现对风机的闭环控制,通入净化空气量大于舱内缝隙出气量,建立超压环境,保证空气来源单一流向,防止舱外有害气体进入舱内。系统壳体屏蔽分析设计、传感器的数字化提高系统在车辆电磁环境中的可靠性,模块化设计增加系统的可互换性。经过舱内试验,验证了系统检测舱外有害气体到稳定建立超压环境的可行性。

In order to effectively prevent harmful gas from dangerous chemical environment from entering the cabin from the gap of the vehicle cabin,the method of driving the fan to add purified air to establish overpressure in the cabin is adopted,and the over-pressure measurement and control system based on STM32 single-chip microcomputer is designed.The system uses the MQ135 gas sensor as an example to collect the information of the harmful gas(carbon monoxide,etc)outside the cabin as the trigger signal of the STM32 controller.The pressure sensor collects the pressure difference between the internal and external pressure of the cabin,and uses the incremental PID algorithm to output the PWM wave to realize the closed-loop control of the fan.The amount of purified air is greater than the amount of air in the gap in the cabin,and an overpressure environment is established to ensure a single flow of air source to prevent harmful gases from entering the cabin.The system housing shielding analysis design,the digitization of the sensor improve the reliability of the system in the vehicle electromagnetic environment,and the modular design increases the interchangeability of the system.After in-cabin testing,the feasibility of the system to detect harmful gases outside the cabin to stabilize the establishment of an overpressure environment was verified.