The stepper motor is selected to drive carriage
due to its ability to be controlled in open loop mode with a sufficient accuracy.
Thus each winding turn can be controlled and shifted properly after the
appropriate motor rotary steps have been determined. In most cases, stepper
motors cannot instantly go from a stationary state directly to their maximum
speed due to the slip [7-8]. Rather, they must "ramp up" in speed to attain the
maximum speed. In order to accommodate this, the designed control algorithm
will speed up motor slowly, building up the drive current until it reaches the
required speed, as shown in Fig. 7