通过测量发动机支撑结构应变信号分析车辆实际行驶过程中发动机的受力情况.特种车辆动力舱内部具有环境温度高、噪声来源复杂等特点,影响测试电路对微小信号的萃取.为解决发动机支撑结构小信号不易获取、测量不准确等问题,该文设计一种以仪表放大器为核心的测试电路,可以对微伏级的微小电压信号采集放大.电路采用差分放大,隔离放大等设计具有抑制共模干扰、抑制温漂、稳定性好和抗干扰性强等特点.模拟台架实验结果显示测试系统可以有效获取微小应变信号,信号质量较好.%The stress condition of engine during running of a vehicle can be analyzed by measuring the strain signals of engine fulcrum bearing structure. The engine cabin of a special vehicle has characteristics including high ambient temperature and complex noise sources, which affect the extraction of weak signal by the test circuit. In order to solve the problems that the weak signal of engine fulcrum bearing structure cannot be easily obtained and measured accurately, the paper designs a test circuit cored with instrumentation amplifier to acquire and amplify the weak microvolt signal. The circuit is designed with a differential amplifier and an isolation amplifier, which have the characteristics of suppressing common mode interference, restraining temperature drift, good stability and strong anti-interference. The simulation results show that the test system can obtain the weak strain signal effectively and the signal quality is good.
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