Testing system

A testing system comprising:

• dynamometers which are respectively coupled to an input shaft and an output shaft of a test piece which can change a transmission gear ratio between input and output;
• a speed detector that generates a speed detection signal corresponding to a shaft speed of either one of the input shaft and the output shaft;
• a torque detector that generates a torque detection signal corresponding to a shaft torque of one other of the input shaft and the output shaft;
• a speed controller that controls the dynamometer coupled to the one of the input shaft and the output shaft such that a deviation between a speed command signal corresponding to a command for the speed, and the speed detection signal is eliminated;
• and
• a torque controller that controls the dynamometer coupled to the other one of the input shaft and the output shaft such that a deviation between a torque command signal corresponding to a command for the torque, and the torque detection signal is eliminated,
• wherein a control gain of the speed controller is set such that a real part of a pole of a speed control system closed-loop transfer function from the speed command signal to the speed detection signal becomes larger in a negative direction than a value obtained by multiplying a resonant frequency of a control target including the test piece by a negative sign, and
• a control gain of the torque controller is set such that a real part of a pole of a torque control system closed-loop transfer function from the torque command signal to the torque detection signal becomes smaller in the negative direction than the real part of the pole of the speed control system closed-loop transfer function.