Choosing Rotation Ranges for Servo Motors

Servo motors are controlled by messages made up of varying pulses, which determine the degree to which the device will rotate. This specific communication and rotation is essential to the precise positioning that the small devices provide. The position of the machine is read by a potentiometer, which gives the user vital information in the proper working of the motor. The potentiometer reads the position by coupling with the output shaft, which is the major rotating part in the machine.

When the rotation of the output shaft shifts, the resistance reading of the potentiometer changes accordingly, providing a reading that is directly proportional to the exact angle of the rotation. The pulse fed to the servo motor is converted into a steady analogue voltage to keep the device in a constant and correct position. An error amplifier also constantly checks the voltage against the rotated position of the output shaft to ensure that the device is operating in precisely the right rotational range.

If needed, the rotation range of a servo motor can be adjusted to suit a new application or to allow for slippages in precision over time. This adjustment is a common practice in the maintenance and repair of model planes and other small scale robotics. The wiring process can also be complemented by more mechanical repairs, such as lengthening the wings on a model plane to provide more balance and flexibility of the miniature aircraft. For these purposes you can choose between standard models and rotational or continuous models.

Choosing and applying a servo motor for robotics purposes is a highly precise art and requires some knowledge of the safe handling of electrical wiring. When fitting in a rotational device, you should test the machine several times to make sure that your wiring is correct and the rotational range is as you expected. You should first test the operation of the transmitter and channel to gauge the precision of your device's rotational response.

For more complex systems, controllers are available which are capable of giving you the position readings of six or more different devices, each of which may have different rotational ranges. These controllers can configure all of your servo motors automatically, providing a sophisticated system that takes the work out of choosing a rotational range. Complex controllers are capable of working with both standard models, which have a limited movement range, and rotational servos which can rotate freely to any position.