A common actuator In control systems is the DC motor. It directly provides rotary motiom The electric equivalent circuit of the armature and the free-body diagram of the rotor are shown In the following figure 2. Kto(t Figure 2 For this example, we will assume that the input of the system is the voltage source (SVS) applied to the motor's armature, while the output is the rotational speed of the shaft The rotor and shaft are assumed to be rigid. We further assume a viscous friction model, that is, the friction torque is proportional to shaft angular velocity. The physical parameters are: J = 0.01 kg.mz, moment of inertia of the rotor, 0.1 N.m.s, motor viscous friction constant, 0.01 (V/rad/sec, electromotive force (emf) constant, N_m/Amp, motor torque constant) R= I Ohm, electric resistance, O.S H, electric inductance. Based on Newton's Law and Kirchhoff s voltage law, the governing equations or equation of motion of the DC motor system are: