Does the Servo Motor Need to be Equipped with an Encoder?

 

 

A servo motor is a type of rotary actuator that allows for precise control of angular position, velocity, and acceleration. It consists of a motor coupled to a sensor for position feedback, which forms a closed-loop control, allowing the precise control that has made them essential in many applications.

 

This brings us to the question: does a servo motor need to be equipped with an encoder? The simple answer is yes, and this article will explore why this is the case.

 

 

 

Function of a Servo Motor

Before delving into the role of encoders in servo motors, it's essential to understand how a servo motor functions. A servo motor is designed to respond to a signal and move to a specific position. This movement is controlled by providing a varying amount of power to the motor, which results in a corresponding variation in speed and position.

 

However, simply providing power to the motor is not enough to accurately control its position. The system needs a way to know the motor's actual position to make any necessary adjustments. This is where the encoder comes into play.

 

 

 

Role of an Encoder

An encoder is a sensor attached to the motor that provides feedback on the motor's position. This feedback is sent to a control device, which uses this information to adjust the power supplied to the motor to achieve the desired position.

 

The encoder does not control the motor; instead, it provides the necessary data for the control device to do so. Without an encoder, the control device would be working blind, so to speak, without any information about the motor's current position.

 

 

Types of Encoders

Encoders can be classified into two broad types: incremental and absolute.

 

Incremental encoders provide relative position data, meaning they report changes in position but not the absolute position. They are simpler and cheaper than absolute encoders but require a known reference point to function effectively.

 

On the other hand, absolute encoders provide information about the absolute position of the motor. Unlike incremental encoders, they do not require a reference point since they can provide the exact position data at any given time. This makes them more complex and expensive but also more useful in applications where the reference point might be lost, such as a power outage.

 

 

The Importance of an Encoder in a Servo Motor

The main reason why a servo motor needs an encoder is to achieve precise control. Without an encoder, the control device would not have the necessary feedback to adjust the power supplied to the motor accurately. This would result in the motor not reaching the desired position, or overshooting it, both of which are undesirable outcomes.

 

Moreover, encoders also allow for more sophisticated control strategies, such as PID control, which would not be possible without the feedback provided by the encoder.