Improvement of the Dynamical Properties of an Electrical Servo-mechanism by On-Off Switching of the Negative Velocity Feedback
Saburo Aiba · Journal of the Japan Society of Precision Engineering · 1974
It is theoretically shown that the dynamical properties of an electrical servo-mechanism can be remarkably improved by appropriately switching on and off the negative velocity feedback using a tacho-generator, a logical circuit and a relay. The construction of the system and the logical circuit are shown. Denoting by ε the deviation, when (ε+αε) ε>0, the velocity feedback is made off, and when (ε+αε) ε>0, the velocity feedback is made on, where α is an adjustable coefficient. The optimal value of α is nearly inversely proportional to the damping coefficient ratio of the system when the velocity feedback is on. It is shown by computation that using such a mechanism, when the damping coefficient ratio of the system without the velocity feedback is 0.02, the settling time, the integral of the absolute error and the integral of the squared error in the case of the indecial response are made smaller by about 50, 35 and 30 % respectively compared to the case of an ordinary linear servo-mechanism. Simulation by an analog computer and an experiment using a two-phase servo-motor were made and good results were obtained.