Working of Servo Motor
Introduction
A servo motor is a rotary actuator or linear actuator that allows for precise control of angular or linear position, velocity, and acceleration. It consists of a motor coupled to a sensor for position feedback. Servo motors are widely used in robotics, CNC machinery, automated manufacturing, and control systems.
Components of a Servo Motor System
- DC Motor or AC Motor – The main driving element.
- Position Sensor (usually a potentiometer) – Provides feedback on the shaft position.
- Control Circuit – Compares the desired position with the actual position and adjusts the motor accordingly.
- Gear Train – Provides torque multiplication and speed reduction.
- Output Shaft – The shaft that performs the mechanical work.
Working Principle
- The servo motor receives a control signal representing the desired output position (angle).
- The position sensor measures the current position of the motor shaft and sends this feedback to the control circuit.
- The control circuit compares the actual position with the desired position.
- If there is any difference (error), the control circuit energizes the motor to rotate the shaft towards the desired position.
- When the shaft reaches the target position, the error becomes zero, and the motor stops.
- This feedback loop continuously maintains the shaft position accurately.
Detailed Working Steps
- Input Command Signal: The control system sends a command specifying the desired angular position.
- Feedback from Sensor: The potentiometer or encoder attached to the shaft senses the current position.
- Error Signal Generation: The control circuit subtracts the actual position from the desired position, creating an error signal.
- Motor Activation: Based on the error signal, the motor rotates in the required direction.
- Correction and Stop: As the motor shaft approaches the commanded position, the error reduces until it reaches zero, causing the motor to stop exactly at the target.
Neat Sketch Description
- A motor connected to an output shaft.
- A gear train connected to the motor shaft.
- A position sensor (potentiometer) mounted on the output shaft.
- A control circuit block with inputs:
- Desired position (input command)
- Feedback from the position sensor
- Arrows showing:
- Input command going to control circuit
- Feedback from sensor going to control circuit
- Control circuit sending signal to motor
- Motor rotating shaft to correct position
Label all parts clearly and add a caption:
Block diagram showing working of a servo motor