What Is Servo? How does it Improve Precision in RC steering?

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Running an RC car is fun using a controller with your desired commands. You can guide the car in any direction, which is an action of the servo behind. The device’s name might be very familiar to you as an RC lover. But beginners can be eager to note – what is a servo?

A servo, also called a servo motor, is a self-contained electrical device to rotate machines’ parts or control motions with high efficiency and precision. It is a crucial part of RC cars since it plays the primary role in steering them. 

The device precisely controls angular or linear position, velocity, and acceleration. That is why servos are widely used in RC vehicles, robotics, automation, and many other applications where the mechanism requires precise motion control.

The above section is an essence of a great explanation. We have gathered many other things to explore about servo that a beginner will admire. Let’s check out the entire article to discover them.

Advantages of Servo

A servo is not a simple rotation motor; instead, it gives users added benefits. Let’s check out some points representing the advantages of a servo.

1. A servo works with higher accuracy by providing precise positioning and velocity control.

2. Servo motors are more energy efficient and intelligent than other motion motors. 

3. The device is relatively small and can be used in various applications.

4. A servo performs with no vibration, a unique characteristic of the device. 

5. It works 2 to 3 times faster than typical stepper motors, allowing users for high-speed motion control.

Is Servo Motor A Sensor?

A servo is not a sensor, though its performance includes precision. It is rather an actuator that receives input from a sensor and controls its rotation accordingly. A servo motor is technically an output device. It takes an analog or digital input signal and converts it into an output action.

It is a big reason that servo is widely used in robotics. Unlike regular CC motors, a servo lets you adjust the desired position with the highest movement control. Servos are also lighter, making them compatible with robots and RC cars.

Servo motors can deliver better torque and speed control than brushed motors. So, they are ideal for applications requiring precise and repeatable movements. They also provide more intelligence and features than simple cc motors.

What Are the Main Components of a Servo?

The components of a servo can vary depending on its type. However, a servo for RC cars or planes typically has the following components:

A DC motor: It provides the rotational force to the servo.

A gear system: This part translates the turning motion of the motor into linear motion.

A potentiometer: The device detects the current position of the servo shaft.

A control circuit: It evaluates the position command with the encoder position or speed information and controls the drive current.

A signal amplifier: This part comes with three different color wires and is used to boost the control signal to drive the motor.

An output shaft: It causes the servo arms to move and transfer the movement to the desired position.

How Does A Servo Motor Work?

A servo motor works based on position feedback, also called a servo mechanism. A servo system includes several parts that we have already mentioned above.

The motor in a servo system is controlled by an electrical pulse, also known as Pulse Width Modulation (PWM). The motor receives the pulse through the control wire. 

The pulse primarily controls the speed and torque of the motor. However, you can adjust the servo motor’s position by sending a specific signal with a specific pulse width.

The frequency of the control signal has to be 50 Hz. It means a pulse should be sent every 20 milliseconds. 

After providing instruction to the servo with the accurate pulse, it will rotate to your preferred position. To manage the mechanism, you will need a microcontroller or a radio control receiver to send pulses.

Servo Motor Rotation Angle

Servo motors for RC vehicles and other pieces of machinery come with different required rotation angles. Users can also modify the turning angle of servos based on their needs. 

Standard servos can rotate up to 180°. There is also a special type of servo motor called “continuous servo,” which can rotate 360 degrees and more continuously. 

Special servos are also available, designed to rotate in both directions.

Types of Servo Motors

Servo motors have distinctions and are often modified for particular actions. They can differ in several aspects, including their generations, energy sources, and rotational limits.

 Servo motors can be both analog and digital. Here are the quick differences between analog and digital servos:

Digital servo: Digital servos are faster at sending pulses. It transfers pulses six times faster than analog servos. The servo also provides more consistent torque for quicker and smoother control.

Analog servo: Analog servos are comparatively slower at sending pulses, which are about 50 pulses per second. They are cheaper and still sufficient for most users. 

Servos can be characterized into two types based on their energy utilization. They are:

AC servo: AC servos use alternating current to generate the rotary motion. They are high-powered which assists in generating higher torque.

DC servo: DC servos use direct current to produce linear motion. They are more accurate and reliable, which is suitable for precision applications. 

Servos have three different types based on their rotational limit and mechanism. They are:

Positional rotation servo: The most common servo that rotates the output shaft up to 180 degrees.

Continuous rotation servo: An improved version of servos that provides open-loop speed control.

Linear servo: An actuator that create straight line motion instead of circular motion.

Servo vs. Stepper Motor

Because of the similar operations, many users may think that servo and stepper motors are the same things. But, they are different in many aspects. Here is a comparison chart to clarify their differences.

Servo motorStepper motor
It has a lower pole count, which is from 4 to 12.Its pole count is higher, between 50 and 100.
Servo provides more accuracy in controlling motions.Stepper’s motion-controlling system is comparatively less accurate.
It is suitable for a closed-loop controlling system.It is suitable for an open-loop controlling system.
Servos require feedback to maintain accuracy.Steppers require no feedback.
Its operation is significantly faster.Its operation is comparatively slower.
Servo is appropriate for high-speed and high-torque applications.Steppers are better suited for lower acceleration and high-precision applications.
It costs higher than other motion controllers.This motor is cost-effective for most users.

Frequently Asked Questions

1. Is a servo motor an actuator?

Yes. It is a kind of rotary actuator or linear actuator that provides precise and repeatable movements.

2. What is a servo saver?

A servo saver is a horn or arm of a servo that protects a servo motor from sudden shock or load. It limits the amount of force and helps to reduce the risk of damaging the servo motor, servo arm, and other components.

3. Does the servo motor need a motor driver?

Yes. A servo motor needs a motor driver to complete the servo system. It controls the speed and position of the motor based on signals from the control system.

Final words

Finally, you should be well informed about a servo’s uses and functions. The device doesn’t only help rotate your RC’s steering. Instead, it will give you more control over your RC vehicle and change the game ultimately. A good servo will surely add extra excitement to your RC driving experience. After reading the article, it should make sense why a servo is crucial for RCs.

About the author

Travis Murray

I am Travis Murray, and my love for RC began in 2017. It gradually turned into a passion, leading me to become an RC enthusiast and blogger. I write in-depth reviews and DIY guides for RC enthusiasts to provide troubleshooting tips and insider knowledge to help starters find the hidden gems in the hobby.
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