What is a Servomotor?
A servo motor is a type of motor that rotates with high precision.
Normally, this sort of motor has a control circuit which provides feedback on current position of the motor shaft; this feedback allows servo motors to rotate with great precision.
If required to rotate an object at specified angles or distances, it is necessary to have a servomotor.
It is simply a motor that powers a servo mechanism. If a motor is powered by a DC power supply, it is referred to as a DC servo motor, while an AC-powered motor is referred to as an AC servo motor.
This post will just cover how a DC servo motor works.
Aside from these broad categories, there are numerous different varieties of servo motors based on gear arrangement and operational characteristics.
A servo motor is typically equipped with a gear arrangement, allowing us to obtain a high torque servo motor in tiny and lightweight designs.
Because of these capabilities, they are utilized in a variety of applications, including toy cars, RC helicopters and planes, robotics, and so on.
Servo Motor Rating
Servo motors are rated in kg/cm (kilogram per centimeter). The majority of hobby servo motors are rated at 3kg/cm, 6kg/cm, or 12kg/cm. This kg/cm indicates how much weight your servo motor can raise over a certain distance.
The position of a servo motor is determined by an electrical pulse, and the electronics is located beside the motor.
Servo Motor Working Mechanism
It is composed of 3 parts:
- Output Sensor
- Controlled Equipment
- Feedback system
It is a closed-loop system that controls motion and the shaft’s end position via a positive feedback mechanism.
The device is regulated by a feedback signal produced by comparing the output signal to the reference input signal.
The reference input signal is compared to the reference output signal, and a third signal is generated by the feedback system.
And the third signal serves as an input signal to control the device.
This signal exists as long as the feedback signal is active or there is some variation between the reference input signal & the reference output signal.
So the primary function of a servomechanism is to keep the output of a system at the correct value in the face of noise.
Working Principle of Servo Motor
A servo includes
- Motor (DC or AC ),
- Potentiometer,
- Gear Assembly, And
- Control Circuit.
First and foremost, we use a gear arrangement to lower RPM while increasing motor torque.
Assume that the potentiometer knob is positioned so that no electrical signal is created at the potentiometer’s output port when the servo motor shaft is in its initial position.
An electrical signal is now sent to another input terminal on the error detecting amplifier.
The difference between these two signals, one from the potentiometer and the other from other sources, will be analyzed in a feedback mechanism, and the output will be in the form of an error signal.
This erroneous signal functions as the motor’s input, and the motor begins to rotate.
Now, the motor shaft is linked to the potentiometer, and when the motor rotates, so does the potentiometer, generating a signal.
As the potentiometer’s angular position changes, so does the output feedback signal.
After some time, the position of the potentiometer reaches a point where its output matches the external signal provided.
At this point, there is no output signal from amplifier to motor input since there is no difference between the externally supplied signal and the signal created by the potentiometer, and the motor stops rotating.