A servo motor is a feedback motor. The rotation from the rotor of the engine is transmitted to the control mechanism through the gearbox, and the feedback is realized using a control unit connected to the rotation angle sensor.
Servo motors are used in automotive systems for linear and angular movement of elements, the position accuracy of which is more demanding. The operation of the servo drive is based on the adjustment of the operation of the electric motor to execute the control signal.
Purpose and composition
If the angle of rotation of the motor output shaft is specified as a control signal, it is converted into an applied voltage. Feedback is carried out thanks to a sensor measuring one of the output parameters of the motor. The value of the sensor readings is processed by the control unit, after which the servo motor operation is corrected.
Structurally, a servo drive is an electromechanical unit, the elements of which are located in a single housing. The servo drive includes an electric motor, a gearbox, a sensor and a control unit.
The main characteristics of a servo drive are operating voltage, rotation speed, torque, as well as design solutions and materials used in a particular model.
Design and work features
In modern servo drives, 2 types of electric motors are used - with a core and with a hollow rotor. Core motors have a rotor with a winding around which DC magnets are located. The peculiarity of this type of electric motors is the occurrence of vibrations during the rotation of the pendulum, which somewhat reduces the accuracy of angular movements. Hollow-rotor motors are devoid of this drawback, but more expensive due to the complexity of the manufacturing technology.
Servo gearboxes are used to reduce the speed and increase the torque on the output shaft. Servo gearboxes in most cases consist of a spur gear train, the gears of which are made of metal or polymer materials. Metal gearboxes are more expensive, but stronger and more durable.
Depending on the required accuracy of operation, plastic bushings or ball bearings can be used in the design of the servo drives to orient the output shaft relative to the housing.
Also, servos are distinguished by the type of control unit. There are analog and digital servo control units. The digital block allows you to provide more accurate positioning of the servo actuator and a faster reaction speed.
