Servo Motor and Controller Guide - Revision history

Mparadis at 21:53, 11 July 2023

2023-07-11T21:53:23Z

← Older revision		Revision as of 21:53, 11 July 2023
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	==How it Works==		==How it Works==
	A typical servo motor consists of a small [[DC Motor and Controller Guide\|DC motor]] driving a gearbox. A ~~[[Potentiometer Guide\|~~potentiometer]] is connected to the output shaft and through the use of some simple electronics, a closed-loop control system is created to monitor and command the motor to move to a specific position. Servos run on a pulse-width modulation (PWM) signal which is a series of square waves where the width of the wave is altered from pulse to pulse. For example:		A typical servo motor consists of a small [[DC Motor and Controller Guide\|DC motor]] driving a gearbox. A potentiometer is connected to the output shaft and through the use of some simple electronics, a closed-loop control system is created to monitor and command the motor to move to a specific position. Servos run on a pulse-width modulation (PWM) signal which is a series of square waves where the width of the wave is altered from pulse to pulse. For example:

	[[File:Servo_PWM.jpg\|link=\|center]]		[[File:Servo_PWM.jpg\|link=\|center]]
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	===Digital Servo===		===Digital Servo===
	Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a [[DC Motor and Controller Guide\|DC motor]], a ~~[[Potentiometer Guide\|~~potentiometer]], and a small analog circuit which acts as a controller to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them with Phidgets Inc. servo controllers.		Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a [[DC Motor and Controller Guide\|DC motor]], a potentiometer, and a small analog circuit which acts as a controller to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them with Phidgets Inc. servo controllers.

	Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.		Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.

Lmpacent at 20:03, 26 June 2023

2023-06-26T20:03:40Z

← Older revision		Revision as of 20:03, 26 June 2023
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	{{#seo:\|description=Learn about servo motors and servo motor controllers in this guide, including: how servo motors work, how to choose a servo motor, types of servo motors, and more.}}		{{#seo:\|description=Learn about servo motors and servo motor controllers in this guide, including: how servo motors work, how to choose a servo motor, types of servo motors, and more.}}
			{{#seo:\|keywords=servo motor}}
	[[Category:IntroGuide]]		[[Category:IntroGuide]]
	__TOC__		__TOC__

Mparadis at 19:56, 1 June 2023

2023-06-01T19:56:34Z

← Older revision		Revision as of 19:56, 1 June 2023
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	==Introduction==		==Introduction==
	[[Image:RCC1000.jpg\|link=\|400px\|right]]		[[Image:RCC1000.jpg\|link=\|400px\|right]]
	The broad definition of a servo motor is an automatic device with some sensing mechanism to correct its performance. This ~~primer~~ refers specifically to RC servos.		The broad definition of a servo motor is an automatic device with some sensing mechanism to correct its performance. This guide refers specifically to RC servos.

	RC Servos are used for positioning applications. They were originally designed to control remote control (RC) airplanes and their low cost and high torque makes them very useful as an actuator in prototyping applications. An RC Servo can be instructed to move to a desired position by the controller. Internally, it monitors the current position, and drives the motor as fast as it can until it reaches the desired position. This is a very cheap and simple way to control a motor. It has some limitations - there is no way for the controller to know the current position and speed of the motor. Applications that want smooth movement suffer from the aggressive acceleration.		RC Servos are used for positioning applications. They were originally designed to control remote control (RC) airplanes and their low cost and high torque makes them very useful as an actuator in prototyping applications. An RC Servo can be instructed to move to a desired position by the controller. Internally, it monitors the current position, and drives the motor as fast as it can until it reaches the desired position. This is a very cheap and simple way to control a motor. It has some limitations - there is no way for the controller to know the current position and speed of the motor. Applications that want smooth movement suffer from the aggressive acceleration.

	==How it Works==		==How it Works==
	A typical servo motor consists of a small [[DC Motor and Controller ~~Primer~~\|DC motor]] driving a gearbox. A [[Potentiometer ~~Primer~~\|potentiometer]] is connected to the output shaft and through the use of some simple electronics, a closed-loop control system is created to monitor and command the motor to move to a specific position. Servos run on a pulse-width modulation (PWM) signal which is a series of square waves where the width of the wave is altered from pulse to pulse. For example:		A typical servo motor consists of a small [[DC Motor and Controller Guide\|DC motor]] driving a gearbox. A [[Potentiometer Guide\|potentiometer]] is connected to the output shaft and through the use of some simple electronics, a closed-loop control system is created to monitor and command the motor to move to a specific position. Servos run on a pulse-width modulation (PWM) signal which is a series of square waves where the width of the wave is altered from pulse to pulse. For example:

	[[File:Servo_PWM.jpg\|link=\|center]]		[[File:Servo_PWM.jpg\|link=\|center]]
Line 45:		Line 45:

	===Digital Servo===		===Digital Servo===
	Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a [[DC Motor and Controller ~~Primer~~\|DC motor]], a [[Potentiometer ~~Primer~~\|potentiometer]], and a small analog circuit which acts as a controller to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them with Phidgets Inc. servo controllers.		Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a [[DC Motor and Controller Guide\|DC motor]], a [[Potentiometer Guide\|potentiometer]], and a small analog circuit which acts as a controller to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them with Phidgets Inc. servo controllers.

	Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.		Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.

Lmpacent at 17:14, 24 May 2023

2023-05-24T17:14:50Z

← Older revision		Revision as of 17:14, 24 May 2023
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	~~<metadesc>Servo~~ motors ~~are controlled by pulse-code modulation~~ and ~~are used for position-controlled movement. Learn~~ more ~~at Phidgets.com~~.~~</metadesc>~~		{{#seo:\|description=Learn about servo motors and servo motor controllers in this guide, including: how servo motors work, how to choose a servo motor, types of servo motors, and more.}}
	[[Category:IntroGuide]]		[[Category:IntroGuide]]
	__TOC__		__TOC__

Mparadis at 19:06, 16 May 2023

2023-05-16T19:06:28Z

← Older revision		Revision as of 19:06, 16 May 2023
Line 1:		Line 1:
	<metadesc>Servo motors are controlled by pulse-code modulation and are used for position-controlled movement. Learn more at Phidgets.com.</metadesc>		<metadesc>Servo motors are controlled by pulse-code modulation and are used for position-controlled movement. Learn more at Phidgets.com.</metadesc>
	[[Category: ~~Primer~~]]		[[Category:IntroGuide]]
	__TOC__		__TOC__

Mparadis: Mparadis moved page Servo Motor and Controller Primer to Servo Motor and Controller Guide

2023-05-16T17:10:14Z

Mparadis moved page Servo Motor and Controller Primer to Servo Motor and Controller Guide

← Older revision	Revision as of 17:10, 16 May 2023
(No difference)

Mparadis at 19:26, 19 January 2018

2018-01-19T19:26:43Z

← Older revision		Revision as of 19:26, 19 January 2018
Line 4:		Line 4:

	==Introduction==		==Introduction==
	[[Image:~~1061~~.jpg\|link=\|400px\|right]]		[[Image:RCC1000.jpg\|link=\|400px\|right]]
	The broad definition of a servo motor is an automatic device with some sensing mechanism to correct its performance. This primer refers specifically to RC servos.		The broad definition of a servo motor is an automatic device with some sensing mechanism to correct its performance. This primer refers specifically to RC servos.

Mparadis at 16:57, 29 November 2017

2017-11-29T16:57:27Z

← Older revision		Revision as of 16:57, 29 November 2017
Line 1:		Line 1:
			<metadesc>Servo motors are controlled by pulse-code modulation and are used for position-controlled movement. Learn more at Phidgets.com.</metadesc>
	[[Category: Primer]]		[[Category: Primer]]
	__TOC__		__TOC__

Lmpacent at 19:46, 6 July 2017

2017-07-06T19:46:26Z

← Older revision		Revision as of 19:46, 6 July 2017
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	[[Category: Primer]]		[[Category: Primer]]
	~~[[Image:3000_1.jpg\|link=\|300px]]~~
	~~[[Image:1061.jpg\|link=\|300px]]~~
	__TOC__		__TOC__


	~~<br clear="all" />~~

	==Introduction==		==Introduction==
			[[Image:1061.jpg\|link=\|400px\|right]]
			The broad definition of a servo motor is an automatic device with some sensing mechanism to correct its performance. This primer refers specifically to RC servos.

	~~The broad definition of a servo motor is an automatic device with some sensing mechanism to correct its performance. This primer refers specifically to '''RC servos'''.~~		RC Servos are used for positioning applications. They were originally designed to control remote control (RC) airplanes and their low cost and high torque makes them very useful as an actuator in prototyping applications. An RC Servo can be instructed to move to a desired position by the controller. Internally, it monitors the current position, and drives the motor as fast as it can until it reaches the desired position. This is a very cheap and simple way to control a motor. It has some limitations - there is no way for the controller to know the current position and speed of the motor. Applications that want smooth movement suffer from the aggressive acceleration.

	RC Servos are used for positioning applications. They were originally designed to control ~~Remote Control~~ airplanes and their low cost and high torque makes them very useful as an actuator in prototyping applications. An RC Servo can be instructed to move to a desired position by the controller. Internally, it monitors the current position, and drives the motor as fast as it can until it reaches the desired position. This is a very cheap and simple way to control a motor. It has some limitations - there is no way for the controller to know the current position and speed of the motor. Applications that want smooth movement suffer from the aggressive acceleration.

	==How it Works==		==How it Works==
	A typical servo motor consists of a small [[DC Motor and Controller Primer\|DC motor]] driving a gearbox. A [[Potentiometer Primer\|potentiometer]] is connected to the output shaft and through the use of some simple electronics, a closed-loop control system is created to monitor and command the motor to move to a specific position. Servos run on a pulse-width modulation (PWM) signal which is a series of square waves where the width of the wave is altered from pulse to pulse. For example:		A typical servo motor consists of a small [[DC Motor and Controller Primer\|DC motor]] driving a gearbox. A [[Potentiometer Primer\|potentiometer]] is connected to the output shaft and through the use of some simple electronics, a closed-loop control system is created to monitor and command the motor to move to a specific position. Servos run on a pulse-width modulation (PWM) signal which is a series of square waves where the width of the wave is altered from pulse to pulse. For example:

	[[File:Servo_PWM.jpg\|link=]]		[[File:Servo_PWM.jpg\|link=\|center]]

	The width of each pulse corresponds to a specific rotational position, and different servo motors are mapped differently depending on their range of motion and resolution. For example, the 1 ms pulse in the diagram above might map to a position -45° from the zero position, while the 2 ms pulse might map to the +90° position. This differs slightly from conventional pulse-width modulation because the modulation serves only as an encoded command, and is not used to power the device (The servo motor is powered via the +5V line, not the PWM data line).		The width of each pulse corresponds to a specific rotational position, and different servo motors are mapped differently depending on their range of motion and resolution. For example, the 1 ms pulse in the diagram above might map to a position -45° from the zero position, while the 2 ms pulse might map to the +90° position. This differs slightly from conventional pulse-width modulation because the modulation serves only as an encoded command, and is not used to power the device (The servo motor is powered via the +5V line, not the PWM data line).
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	==Choosing a Servo Motor==		==Choosing a Servo Motor==
			[[Image:3000_1.jpg\|link=\|right\|400px]]
	Servos have 3 main attributes that must be taken into account when choosing what servo is correct for your application:		Servos have 3 main attributes that must be taken into account when choosing what servo is correct for your application:

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	===Digital Servo===		===Digital Servo===
	Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a [[DC Motor and Controller Primer\|DC motor]], a [[Potentiometer Primer\|potentiometer]], and a small analog circuit which acts as a ~~[[DC Motor and Controller Primer#PID Loop\|~~controller]] to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them with Phidgets Inc. servo controllers.		Digital servos behave in the same way as traditional servos except their internals are different. Normally, a servo motor consists of a [[DC Motor and Controller Primer\|DC motor]], a [[Potentiometer Primer\|potentiometer]], and a small analog circuit which acts as a controller to keep the motor in position. In the case of digital servos, the analog circuit is replaced with a microprocessor which performs the same function. This allows digital servos to have faster response times, more accurate control of position and velocity, and more torque per size. However, digital servos use substantially more power than their analog counterparts. This means that for the same power supply you will be able to operate fewer digital servos than analog. Depending on the size of the digital servo, you may need an external power supply when using them with Phidgets Inc. servo controllers.

	Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.		Some digital servos are designed such that the control system retains its previous value when position commands stop coming in from the controller. This has the unusual effect of making the motor hold its position forcibly even when you disengage the motor programmatically. This can often be undesirable since it means the motor is still drawing power and that it will not turn. In order to avoid this behaviour with this type of servo you will need to use a relay or switch of some kind on the red wire going to the motor (the power wire) so that you can completely disengage the motor when you need to.

Mparadis at 11:18, 24 November 2016

2016-11-24T11:18:30Z

← Older revision		Revision as of 11:18, 24 November 2016
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	[[Category: Primer]]		[[Category: Primer]]
			[[Image:3000_1.jpg\|link=\|300px]]
			[[Image:1061.jpg\|link=\|300px]]
			__TOC__

	{\|
	~~\|- valign=middle~~
	~~\| align=center width=300px\| __TOC__~~
	~~\| [[Image:3000_1.jpg\|link=\|500px]]~~
	~~\| [[Image:1061.jpg\|link=\|500p]]~~
	\|}

	<br clear="all" />		<br clear="all" />