给出二阶惯性系统阶跃响应斜率和幅值在幅值拐点处的时域表达式及其矩形脉冲响应幅值在其极大值点处的时域表达式,三阶惯性系统阶跃响应斜率在响应的二阶导数极大值点处、阶跃响应幅值在其拐点处和矩形脉冲响应斜率在响应二阶导数极小值点处的时域表达式,并找到了一种在时域辨识一阶、二阶和三阶惯性系统的方法.实测结果表明,该方法简便、可靠,测试精度高. The time-domain expressions of the slope and amplitude of the step response of the second-order inertial system at the amplitude inflection point and the time-domain expression of the amplitude of the rectangular impulse response at its maximum point are given. The third-order inertial system step response The slope is at the second derivative maximum point of the response. The magnitude of the step response is at its inflection point and the rectangular impulse response slope is in response to the time domain expression at the minimum point of the second derivative, and a The method to identify the first order, the second order and the third order inertial system is shown in the experimental results. The results show that the method is simple, reliable and accurate.