Motion controllers_Stepper and servo
Motion controllers are the key elements in the automation industry. Where ever the precise operation takes place in a machine, the motion controllers are applied for the particular task. Mainly two types of motors are used for this that are servo motors and stepper motor’s the name says the servo motor run continues and the stepper motor works as stepping angles. In any motion controller application, the motor does not work if it simply getting power supplies, the motor works like a slave and the driver acts as the master. A motor driver id needed for takes placing the motion controller application. In servo motor, the numbers of poles are 4 to 12 and in stepper motor typically use 50 t0 100 numbers of poles. A pole is an area of a motor where a North or South magnetic pole is generated either by a permanent magnet or by passing current through the coils of a winding.
In every motion control application, the motor and driver is connected in a closed loop system in every moments the motor should give feedback to the motor drive. In servo motor the rotor shaft is connected with the encoders, there we are using different methods for obtaining pulses from the motion of the rotor on the basis of the application. In case of stepper motor there do not require encoders and it accurately move in between the poles Servo motor works on PWM (Pulse width modulation) principle, means its angle of rotation is controlled by the duration of the applied pulse to its Control PIN. Basically servo motor is made up of DC motor which is controlled by a variable resistor (potentiometer) and some gears. Servo motors achieve high speed at high torque values. Quiet at high speeds. Encoder utilization provides higher accuracy and resolution with closed-loop control. Working of Permanent Magnet Stepper Motor. The operation of this motor works on the principle that unlike poles attract each other and like poles repel each other. When the stator windings are excited with a DC supply, it produces magnetic flux and establishes the North and South poles. Advantages of step motors are low cost, high reliability, high torque at low speeds and simple, rugged construction that operates in almost any environment. The main disadvantages in using a stepper motor are the resonance effect often exhibited at low speeds and decreasing torque with increasing speed.