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What is a position servo?
A servomotor is a closed-loop servomechanism that uses position feedback to control its motion and final position. The input to its control is a signal (either analogue or digital) representing the position commanded for the output shaft.
How does an analog servo work?
Analog Servos operate based on voltage signals that come through the pulse width modulation (PWM). When an analog servo is at rest, the PWM is essentially off unless you transmit some action. Producing torque from the resting mode makes the initial reaction time sluggish.
How does a servo motor hold position?
A servo motor contains electronics that are internally turning a DC motor on and off as necessary to hold the target position. If the target does not match the current position, it turns on the motor to turn until the two match.
When do you use an analog servo drive?
For this reason, analog drives are commonly used when the motor’s velocity or position needs to be precisely controlled. In fact, when position is the most important parameter, analog servo drives are often used in velocity mode with higher-level controllers having responsibility for the position control.
Can you tell the position of a servo motor?
You have no way of easily determining a servo motors’ actual shaft position, you have to assume that the servo has obeyed your command and is now resting where you want it to. This may not be true, especially if the motor has been subject to an external force. An Analog Feedback Servo Motor can resolve these issues.
Can a feedback servo be used as an input device?
With an analog feedback servo, you can read the motor position and determine exactly when it has arrived at its destination. You can also use the servo motor as an input device, as the feedback signal output will vary as the motor shaft is turned.
How does an open loop RC servo work?
For the familiar RC Servo motor, the position of the output shaft is measured and fed back to the internal control circuit which adjusts current to the motor to maintain position. An “Open Loop” system has no feedback, so there is no way to verify that it is performing as expected.