复合间接式胎压监测机制研究

Research on monitoring mechanism of compound indirect tire pressure

轮胎充气不足会导致轮胎的结构不稳定,从而使轮胎爆裂的可能性增加,事故发生风险的可能性也随之增加,是一种极度危险的情况,因此对胎压进行监测从而减少爆胎的发生在汽车安全研究领域具有重要意义。提出了一种频率法与滚动半径法相结合的复合间接式胎压监测算法,当4个轮胎中只有某一个轮胎单独欠压或有任意2个轮胎欠压时采用半径法,其余所有情况均采用频率法。为了提高胎压监测的精度,对ABS轮速传感器测得的轮速信号进行了进一步的筛选。频率法基于快速傅里叶变换将筛选后的轮速信号转变为频率信号,利用高通滤波去除5 Hz以下对估计共振频率有干扰的频率,然后对得出的频率曲线进行平滑处理,通过均值估计得到轮胎的共振频率;半径法是由筛选后的轮速信号推导出轮胎的滚动半径,再经归一化处理,通过判断相对滚动半径来判断胎压情况,弥补了频率法处理一轮欠压和两轮欠压不足的情况,两者相结合后更能有效地监测出汽车的胎压情况。

Insufficient inflation of tires tend to cause the structural instability of the tire,which increases the possibility of such dangerous situations as tire blowout and accident risk.Therefore,it is of great significance to monitor the tire pressure to reduce tire blowout in the field of automobile safety research.In this paper,a compound indirect tire pressure monitoring algorithm combining frequency method and rolling radius method is proposed.When only one tire pressure is insufficient or any two tires pressure are insufficient,the radius method is adopted,and the frequency method is adopted in all other situations.In order to improve the precision of tire pressure monitoring,the wheel speed signal measured by ABS wheel speed sensor is further screened.The frequency method is used to transform the filtered wheel speed signal into frequency signal based on fast Fourier transform.The high-pass filter is used to remove the frequency below 5 Hz,which interferes with the estimation of resonant frequency.Then the obtained frequency curve is smoothed,and we use mean value estimation to estimate the resonant frequency of the tire.The radius method deduces the rolling radius of the tire from the screening of wheel speed signals.It indirectly judges the tire pressure by the relative rolling radius after normalization,which complements the disadvantages of frequency method to deal with the insufficiency of one tire and any two tires.The combination of the two tire pressure algorithms can more effectively monitor the tire pressure of the vehicles.