What is a gimbal? at DVinfo.net

Jonathan Stanley · January 24th, 2004, 10:03 PM

I have seen these in pictures and heard about them, but really, what are they?

Mike Rehmus · January 24th, 2004, 10:23 PM

Know the two rings that hold a ship's compass and allow it to stay level while the box or binnacle in which it sets tilts?

http://www.mathworks.com/access/help...h/gimbal.shtml

Was turned up with a very simple Google search. Just type in Gimbal and this URL was listed on the first page.

Charles King · January 25th, 2004, 04:09 AM

Jonathan, A gimbal is simply(not to be taken too literally), a bearing system that allows the sled to rotate freely in all three of it's axis. It is made up of bearings which control the pan, tilt and roll of the sled. It is simply a part of the steadicam system that helps control the sled with it's mounted camera in time and space and at the same time helps in preventing outside forces from acting upon the sled.

To be exact, it uses inertia to resist rotation whenever a force imminates through the steadicam Arm. It is also responsible for placing the sled at it's center of gravity or CG, or usually just below it. It is also one of the most important part in the steadicam system. Next comes the arm.

Charles P. probably have something else to add. Maybe he might just correct me if I missed or got something wrong :)

Charles Papert · January 25th, 2004, 02:53 PM

You got it, Charles.

Mike Rehmus · January 25th, 2004, 05:38 PM

I know what you are saying but you are contributing effects to the gimbal in which it can play no part.

A gimbal has only two degrees ( X & Y tilt ) of motion freedom. If it's outer ring is held steadily horizontal, it resists motion in the Z-axis. Z-Axis motion in allowed by the user's arm or the spring-loaded arm that is hung on the vest.

The gimbal doesn't resist anything except vertical motion in this application. It is really just a 2-axis bearing setup that allows the inner ring to tilt in both axis simultaneously. In fact, resistance is the last thing one wants from a gimbal in the two allowed degrees of freedom.

Inertia is the element that creates the resistance.

The responsibility for CG is in placement of the weights. Through application of those weights after proper placement of the camera, CG is established at or very near the gimbal.

I know, I know, I'm being anal about this. :-))

Charles Papert · January 26th, 2004, 12:29 AM

It's a bit confusing because we didn't actually define if we were discussing gimbals in general or those used on a Steadicam in general.

If one were to consider a true three axis gimbal, with the axes representing pan, tilt and roll, it would incorporate a series of concentric rings with the inner controlling pan by means of a circular bearing, and the outer two affecting tilt and roll with pivots at 90 degrees to each other. This was the original Steadicam gimbal design, but it was quickly realized that the limited degree of movement afforded by this design would handicap the operator too much in the tilt axis. Thus this pivot was moved back to the handle attached to the gimbal, allowing 360 degree rotation vs the 45 degree planetary ring design.

If I understand how you are defining "z" axis, Mike, perhaps we can agree that there are three angular axes: pan, tilt and roll (X,Y, Z) and three spatial axes, fore and aft, side to side and up and down (also X, Y and Z). Gimbals only act on angular axes. Yes?

Otherwise, you are correct about inertia and resistance. We could reword Charles K's comments to "gimbal-based stabilizer" and they might be more accurate. Yes again?

Mike Rehmus · January 26th, 2004, 12:46 AM

Yes and yes.

I've only machined a modification for a Glidecam for a DP and other than examining a Steadycam at NAB, I've not had one in my hands. Superficially they look similar but the Glidecam that I worked on was crudely manufactured in areas although the gimbal was OK. I seem to remember that the Steadycam looked a bit more tidy.

Charles King · January 26th, 2004, 01:36 AM

I guess I could hav gone into the real technical clarification but as Charles P. stated. I was relating a gimbal to a steadicam based device. sorry :/
I imagine that what he wanted to know.

Dave Largent · January 26th, 2004, 02:43 AM

If you have to ask: you've never seen anything
like it -- atleast the SteadiCam version. Wouldn't
want to try to build one at home.

Mike Rehmus · January 26th, 2004, 10:23 AM

Charles,

There is no 'sorry' here in any way. The functional part of the post was much better than my first post about the compass.

Building one isn't really difficult if you have the tools. Making the results work correctly takes experience both for the builder and the user, I'd guess.

Jonathan Stanley · January 26th, 2004, 02:20 PM

Haha, well, I now know more than I ever need to about a gimbal. Thanks guys :)

I realized that i was confusing a gimbal with a hi-hat. what is a hi-hat?

Mike Rehmus · January 26th, 2004, 03:23 PM

AFAIK, a High Hat is the equivalent of a very low tripod. It is a base shaped sort of like a High Hat in the top of which is an appropriate receptical for a tripod head. Usually it is a concave hemisphere for accepting a head with a matching convex hemisphere on the bottom.

Rob Lohman · January 27th, 2004, 02:55 PM

Aren't those huge machines on which partial sets are put (or
things like boats) which can then be rocked around also called
gimbals?

January 24th, 2004, 10:03 PM	#1
Jonathan Stanley Regular Crew Join Date: Jul 2003 Location: Boone, NC Posts: 115	What is a gimbal? I have seen these in pictures and heard about them, but really, what are they?

January 24th, 2004, 10:23 PM	#2
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Know the two rings that hold a ship's compass and allow it to stay level while the box or binnacle in which it sets tilts? http://www.mathworks.com/access/help...h/gimbal.shtml Was turned up with a very simple Google search. Just type in Gimbal and this URL was listed on the first page. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

January 25th, 2004, 04:09 AM	#3
Charles King Major Player Join Date: Mar 2003 Location: sweden Posts: 795	Jonathan, A gimbal is simply(not to be taken too literally), a bearing system that allows the sled to rotate freely in all three of it's axis. It is made up of bearings which control the pan, tilt and roll of the sled. It is simply a part of the steadicam system that helps control the sled with it's mounted camera in time and space and at the same time helps in preventing outside forces from acting upon the sled. To be exact, it uses inertia to resist rotation whenever a force imminates through the steadicam Arm. It is also responsible for placing the sled at it's center of gravity or CG, or usually just below it. It is also one of the most important part in the steadicam system. Next comes the arm. Charles P. probably have something else to add. Maybe he might just correct me if I missed or got something wrong :) __________________ Charles 'What we perceive to be may not be what we believe to be.'

January 25th, 2004, 02:53 PM	#4
Charles Papert Wrangler Join Date: Jan 2002 Location: Los Angeles, CA Posts: 6,810	You got it, Charles. __________________ Charles Papert www.charlespapert.com

January 25th, 2004, 05:38 PM	#5
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	I know what you are saying but you are contributing effects to the gimbal in which it can play no part. A gimbal has only two degrees ( X & Y tilt ) of motion freedom. If it's outer ring is held steadily horizontal, it resists motion in the Z-axis. Z-Axis motion in allowed by the user's arm or the spring-loaded arm that is hung on the vest. The gimbal doesn't resist anything except vertical motion in this application. It is really just a 2-axis bearing setup that allows the inner ring to tilt in both axis simultaneously. In fact, resistance is the last thing one wants from a gimbal in the two allowed degrees of freedom. Inertia is the element that creates the resistance. The responsibility for CG is in placement of the weights. Through application of those weights after proper placement of the camera, CG is established at or very near the gimbal. I know, I know, I'm being anal about this. :-)) __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

January 26th, 2004, 12:29 AM	#6
Charles Papert Wrangler Join Date: Jan 2002 Location: Los Angeles, CA Posts: 6,810	It's a bit confusing because we didn't actually define if we were discussing gimbals in general or those used on a Steadicam in general. If one were to consider a true three axis gimbal, with the axes representing pan, tilt and roll, it would incorporate a series of concentric rings with the inner controlling pan by means of a circular bearing, and the outer two affecting tilt and roll with pivots at 90 degrees to each other. This was the original Steadicam gimbal design, but it was quickly realized that the limited degree of movement afforded by this design would handicap the operator too much in the tilt axis. Thus this pivot was moved back to the handle attached to the gimbal, allowing 360 degree rotation vs the 45 degree planetary ring design. If I understand how you are defining "z" axis, Mike, perhaps we can agree that there are three angular axes: pan, tilt and roll (X,Y, Z) and three spatial axes, fore and aft, side to side and up and down (also X, Y and Z). Gimbals only act on angular axes. Yes? Otherwise, you are correct about inertia and resistance. We could reword Charles K's comments to "gimbal-based stabilizer" and they might be more accurate. Yes again? __________________ Charles Papert www.charlespapert.com

January 26th, 2004, 12:46 AM	#7
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Yes and yes. I've only machined a modification for a Glidecam for a DP and other than examining a Steadycam at NAB, I've not had one in my hands. Superficially they look similar but the Glidecam that I worked on was crudely manufactured in areas although the gimbal was OK. I seem to remember that the Steadycam looked a bit more tidy. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

January 26th, 2004, 01:36 AM	#8
Charles King Major Player Join Date: Mar 2003 Location: sweden Posts: 795	I guess I could hav gone into the real technical clarification but as Charles P. stated. I was relating a gimbal to a steadicam based device. sorry :/ I imagine that what he wanted to know. __________________ Charles 'What we perceive to be may not be what we believe to be.'

January 26th, 2004, 02:43 AM	#9
Dave Largent Trustee Join Date: Aug 2003 Posts: 1,483	If you have to ask: you've never seen anything like it -- atleast the SteadiCam version. Wouldn't want to try to build one at home.

January 26th, 2004, 10:23 AM	#10
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Charles, There is no 'sorry' here in any way. The functional part of the post was much better than my first post about the compass. Building one isn't really difficult if you have the tools. Making the results work correctly takes experience both for the builder and the user, I'd guess. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

January 26th, 2004, 02:20 PM	#11
Jonathan Stanley Regular Crew Join Date: Jul 2003 Location: Boone, NC Posts: 115	Haha, well, I now know more than I ever need to about a gimbal. Thanks guys :) I realized that i was confusing a gimbal with a hi-hat. what is a hi-hat?

January 26th, 2004, 03:23 PM	#12
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	AFAIK, a High Hat is the equivalent of a very low tripod. It is a base shaped sort of like a High Hat in the top of which is an appropriate receptical for a tripod head. Usually it is a concave hemisphere for accepting a head with a matching convex hemisphere on the bottom. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

January 27th, 2004, 02:55 PM	#13
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	Aren't those huge machines on which partial sets are put (or things like boats) which can then be rocked around also called gimbals? __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors