为了解决双轴串联的旋转机械在临界转速处产生共振问题，搭建了双跨转子实验台，在不改变原有支撑形式的条件下将磁流变阻尼器分别安装在串联的轴1、轴2上，并建立双跨轴系振动的半主动控制系统，采用比例-积分-微分（PID）控制方法，以振幅为反馈参数实时调节阻尼器电流，在线抑制双跨轴系的振动，并在此基础上通过整定PID控制的比例系数K研究其值对振动控制效果的影响。实验结果表明：基于磁流变阻尼器的PID控制系统可以有效控制两个串联轴在临界转速附近的振动；对临界振幅过大的转子宜采用较大K值，而对临界振幅较小的转子可适当减小K值。Abstract：In order to study the vibration problems of rotating machinery consisting of a two-span shaft around its critical speeds, a two-span rotor test rig was built, and two magneto-rheological dampers were installed on the two coupled rotors without changing the original support. Subsequently, by incorporating a proportion-integration-differentiation (PID) control method, a semi-active control system for the two-span rotor system vibration was established. Using vibration amplitude as the feedback parameter, the system controlled the electric currents of the magneto-rheological at any time allowing the rotor system vibration to be controlled online. In addition, in order to study how the proportionality coefficient influences the control effect, the value of K was varied. The experimental results indicated that the PID control system based on magneto-rheological dampers can successfully suppress the vibration of the two coupled rotors at their critical speeds. For higher values of K, the control effect is better, but very large values of K make the control effect worse. Therefore K should be large in the case of a rotor with a large critical vibration and smaller in the case of a rotor with a smaller critical vibration.