The process of fitting sensor ' s output curve with genetic algorithm is studied . the accuracy error of experiments using this signal processing method is less than 0 . 2mm . in the first chapter : the state - of - the - arts of stroke measuring technique used cylinder summarized 设计了信号处理单片机系统,编制了信号处理软件,制作了磁性标尺和传感磁路结构,进行了实验,结果证明,所研究的各项技术是可行的。