Beneficial effects of positive current feedback control of DC motors

The widespread use of DC motors for servomechanisms and robots requires good design expertise of every possible type of control systems. Tachometers and position sensors play a vital role to insure good performances of speed regulators and position followers. This paper shows that the use of an armature current sensor and a positive feedback loop allows for more design freedom when building speed regulators and servomechanisms. Indeed, positive current feedback decreases the transient current peaks and improves precision, especially for speed regulators. The study is based on state space approach and pole placement method. Numerous cases were simulated and results are conclusive.