The topic of the thesis concerns the development of the position control of a linear axis, an axis composed of an electric motor controlled in position and a screw that transform the rotary and linear motion. The motor, in particular, is a DC motor; the sensor to be used to control the position and speed is an encoder. The type of control is a PID carried out by means of an Arduino Board interfaced with Matlab. The thesis project develops in thre part: 1)A brief introduction of the theory on the DC motors and PID controller, its origin, its applicability, its tuning and all the adjustment methods: manual tuning, open loop Ziegler-Nichols methond and Relay method; 2)The construction of the model starting from DC motor identification and its analysis trough the theory of the PWM and its possible application in controlling the motor.