Servo Motor Drives Basics
Servomechanism, or servo motor drive, is commonly found in today’s modern technology. It doesn’t apply only to cars, as you may have heard, but also in aircraft industry, marine industry and robots. Servomechanism is an automatic device that uses negative feedback to detect incorrect performance and consequently, correct it. It’s also known as a hetero-stat, as in different positions.
Servomechanisms generally provide control over a system’s behavior in terms of position, speed and other performances. Mainly, servomechanisms provide the following:
- Position control — servomechanisms can be electronic or partially electronic, using an electric motor device to produce a mechanical force. There are also servo motor drives that use hydraulic, pneumatic and magnetic principles to produce this mechanical force. The basic principle of work is this: any state in which the actual and the wanted values of the measured performance differ, an error signal is being sent and converted into another signal that is used to drive the system in the desired direction.
- Speed control — that’s something you can find in cars. It’s mainly used to control the speed in cars in a way we’ll explain later;
- Other uses — positioning servos are used in many industries, like the military fire control, marine navigation, automatic navigation systems (something we widely use today when going on tours), and hard disks! Hard disk drive works with a magnetic servo with extremely sharp accuracy measured in sub-micrometers.
How do servo motor drives control speed in cars? It’s simple, the gas pedal, sends a signal to the computer in the car telling it how far it’s pressed. Analyzing that signal and other data from the rest of the sensors, the computer sends a signal to the servo to adjust the speed of the car. Then a shaft that is connected to the throttle is rotated and the servo regulates the speed in a fuel-powered car.
The servo motor drive is a servomechanism that includes a drive, motor and and a feedback device. The feedback device is usually and encoder or a potentiometer. Encoders are mainly used for large industrial components in servomechanisms, while inexpensive devices that employ a potentiometer are used in cars.