A servomotor (servo) is an electromechanical device in which an electrical
input determines the position of the armature of a motor. Servos
are used extensively in robotics and radio-controlled cars, airplanes, and
boats.
You will be using an Airtronics 94102 Precision Heavy-Duty
Standard Servo. The position of the armature (See Figure
)
is determined by the duty cycle of a periodic rectangular pulse
train. The duty cycle of a rectangular pulse train is expressed
in %: It is the ratio of the pulse duration to the pulse period times 100%
(See Figure for examples.)
Figure: Illustration of Servomotor Identifying the Armature
Figure: Examples of Duty Cycle Calculation
The receiver sub-circuit of the lab project outputs a DC voltage. Therefore it is necessary to convert the DC voltage produced by the receiver into a rectangular pulse train whose duty cycle is determined by the DC level. In this lab exercise you will investigate how the servo controller circuit accomplishes this conversion from a DC voltage level to a rectangular pulse train with a specific duty cycle.