Industrial standard servo motors have been in use for a long time. They are small in size but have great functions and are mainly used for angle control. Industrial standard servo motors are usually applied in model aircraft, smart cars, robots, and also in industries. For example, the pitching, yawing, and rolling motions of ships and missile attitude changes are all achieved through the cooperation of servo motors. Servo motors are used in many projects, not limited to ships, online manufacturing, pharmaceutical and other industrial controls. The servo circuit is built into the motor unit and has a positionable shaft, usually equipped with a gear. The motor is controlled by an electrical signal, and this electrical signal determines the movement of the shaft.

What's inside a servo motor?

To fully understand the working principle of a servo motor, you need to take a look under the hood. There is a very simple setup inside: a small DC motor, a potentiometer, and a control circuit. The motor is connected to the control wheel through gears. When the motor rotates, the resistance of the potentiometer changes, so the control circuit can accurately adjust the movement and direction of the motor. When the shaft of the motor is at the desired position, the power supply to the motor is stopped. If not, the motor rotates in the appropriate direction. The desired position is sent via an electrical pulse through the signal wire. The speed of the motor is proportional to the difference between its actual position and the desired position. So, if the motor is close to the desired position, it will rotate slowly; otherwise, it will rotate quickly. This is called proportional control. It means the motor only runs as much as necessary to complete the task at hand, and it's a very efficient little thing.

How to control a servo motor?

A servo motor is controlled by sending electrical pulses of variable width or pulse - width modulation (PWM) through the control wire. There are small pulses, [sensitive word] pulses, and a repetition rate. Servo motors usually can only rotate 90° in either direction, for a total of 180°. The neutral position of the motor is defined as the position where the servo has the same potential rotation amount in the clockwise or counter - clockwise direction. The PWM sent to the motor determines the position of the shaft, and it is based on the duration of the pulse sent through the control wire; the rotor will turn to the desired position. Servo motors expect to see a pulse every 20 milliseconds (ms), and the pulse length will determine how far the motor turns. For example, a 1.5 - ms pulse will turn the motor to the 90° position. A pulse shorter than 1.5 ms will move it counter - clockwise towards the 0° position, and any pulse longer than 1.5 ms will turn the servo clockwise towards the 180° position.

When these servo motors are commanded to move, they will move to that position and hold it. If an external force presses the servo while it is holding the position, the servo will not move out of that position. The maximum force that a servo can exert is called the torque rating of the servo. Servos won't hold their positions forever; the position pulse must be repeated to instruct the servo system to stay in place.

Types of servo motors

There are two types of servo motors - AC and DC. AC servos can handle higher electrical surges and tend to be used in industrial machinery. DC servo systems are not suitable for high electrical surges and are usually more suitable for small - scale applications. Generally speaking, DC motors are cheaper than AC motors. These servo motors are also designed for continuous rotation, making them a convenient way to make robots move. They are equipped with two ball bearings on the output shaft to reduce friction and have easy access to the stationary - point adjustment potentiometer.

Applications of industrial standard servo motors

Industrial standard servo motors are used in radio - controlled aircraft to position control surfaces such as elevators, rudders, walking robots, or operate grippers. Servo motors are small in size, with a built - in control circuit and a moderate size. In food service and pharmaceuticals, these devices are designed for harsher environments. Due to repeated washing under high pressure and high temperature to maintain strict hygiene standards, the possibility of corrosion is very high. Servo systems are also used in online manufacturing, where high - repetition but accurate work is required.