To model the DC motor, the effective voltage is the
difference between the applied voltage and back-emf. The motor armature is
modeled as a simple first-order system with resistance *Ra* and inductance
*La*. The motor current is limited to +/- 10.5A.

To compute the back-emf, the back-emf gain *Kbemf* is
multiplied by the angular velocity. Angular velocity is computed using the
electrical torque and load torque.

A set of const blocks defines the required motor
parameters. The motor angular velocity *thetadm* is integrated to yield
position. The electrical torque *Te* is computed using the motor armature
current, and the I2T.MAP look-up table contains the motor’s current-torque
characteristics. This data is obtained from the motor’s specification sheets or
through the vendor. The complete motor model is shown below.

**Note:** The eMotor toolbox includes a full set of
pre-configured, pre-tested, and ready-to-use blocks, such as motors, amplifiers,
loads, sensors, and controllers.