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Using the IDD for what it wasn't designed for, MI Self Portrait
djellison
post May 11 2009, 11:06 PM
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Now I'm wondering if we could see down the left side of the WEB. That's for tomorrow night. In many respects, the self portrait seq I fudged is basically half-way-to-magnet-MI - then wrist-and-turret-o-rama
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RoverDriver
post May 12 2009, 03:12 AM
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QUOTE (djellison @ May 11 2009, 03:46 PM) *
Here it is - 40 deg FOV. I took a sequence of 20 images, but only needed 14 frames to make the attached mosaic.

A rather bad movie of the arm seq I came up with in quicktime - which probably breaks every known IDD keep-safe rule - and the image dropped in to show the FOV, very roughly. In quicktime, you should be able to drag across the second half of the movie to see what I'm attempting to do.


The movie is quite fast but it does not look you sequenced joint motions that would cause a the fsw to throw a fit. If you have the joint angles written down I can try to verify what I see in Hyperdrive.

Paolo


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Stu
post May 12 2009, 05:50 AM
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Well, Spirit might as well take that portrait Doug; looks like she's not going anywhere for a little while. I really love the idea, by the way.


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djellison
post May 12 2009, 06:45 AM
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I can try and estimate the joint angles - (and re-render the motion slower as well) tonight. 600 whrs and no where to drive for a few days - you might get a bit bored smile.gif
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RoverDriver
post May 12 2009, 10:04 AM
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QUOTE (Stu @ May 11 2009, 10:50 PM) *
Well, Spirit might as well take that portrait Doug; looks like she's not going anywhere for a little while. I really love the idea, by the way.



Unfortunately, one of the outcomes of the recent series of warm reboots is that temporarily we cannot use the IDD. This is because in case the rover reboots while doing an IDD motion, we could lose the position knowledge of the various joints. If that happened we would need to re-calibrate the IDD joints and that is a procedure that was never done on Mars before, just at ATLO. Although I have been assured that this is a simple procedure I'm not so sure I would like to compound on the current state of the vehicle.

The use of the IDD is _not_ lost forever, we just need to make sure we can recalibrate on Mars: have a sequence ready to go in case the unfortunate happens.

Paolo


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RoverDriver
post May 12 2009, 10:10 AM
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QUOTE (djellison @ May 11 2009, 11:45 PM) *
I can try and estimate the joint angles - (and re-render the motion slower as well) tonight. 600 whrs and no where to drive for a few days - you might get a bit bored smile.gif


I'm definitely not get bored at all. I was asking about the joint angles since I though you did write a sequence and you had it saved some place. Regarding the movie, when we sequence IDD motions we look at an animation that runs much slower than yours simply to give us time to make sure we don't whack the various components into anything. Some of the collision detection and joint motion analysis is done automatically but RPs are control freaks so we scrutinize every motion carefully.

Do you know if your tool uses the same joint angles conventions as Hyperdrive?

Paolo


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djellison
post May 12 2009, 10:30 AM
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I'm just animating things with 3DS Max - it's an artistic tool rather than anything else. I do have a reference of joint angles and where zero deg is - so I should be able to pull some actual numbers out that will make sense to you. I'll try and make figures for each key-point in the sequence.
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lyford
post May 12 2009, 03:22 PM
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Speaking of using the IDD for which is was not designed, could the arm reach down and push to help get out of the sandtrap as a last resort? biggrin.gif

(I am not serious, but I recall that Phoenix could at least theoretically dragged itself along with it's arm....)


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climber
post May 12 2009, 03:57 PM
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Answer here: http://twitter.com/marsroverdriver


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djellison
post May 12 2009, 06:44 PM
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Right...these are guestimate figures - I don't really know if I have the IDD geometry accurate, and if I'm refering to the angles correctly.

I start with the Shoulder at -24deg (i.e. 'up' from straight out), and an Az of 0
Elbow is at -25deg (again, 'up' from straight out)

That puts the turret at roughly where I do all the motion from. I'm afraid at that point I'm lost - I don't think my axis are accurate for the motion after that - but a combination of turret and wrist should be able to replicate it.

I'm less confident about this next JPG or two - it's the most 'leftward' and 'rightward' arm motion, with the MI looking back under the IDD down the side of the rover, it might show obstructions around the middle wheels - if they're really big smile.gif I'll put money on these breaching keep-out rules, even if they don't break IDD hard-stops.
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Attached File  mi_test_3.mov ( 1.83MB ) Number of downloads: 135
 
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PaulM
post May 12 2009, 07:09 PM
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QUOTE (lyford @ May 12 2009, 04:22 PM) *
Speaking of using the IDD for which is was not designed, could the arm reach down and push to help get out of the sandtrap as a last resort? biggrin.gif

(I am not serious, but I recall that Phoenix could at least theoretically dragged itself along with it's arm....)


I worked with some Beagle 2 hardware designers between Beagle 2's launch and its landing on Mars. Whilst working with them (on something completely unrelated), one of the designers told me that he had suggested giving Beagle 2 mobility by using Beagle 2's robot arm (PAW) to drag Beagle 2 across the surface of Mars. I think that the base of Beagle 2 was so smooth that this might have just worked! wheel.gif
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djellison
post May 12 2009, 07:14 PM
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I often wondered if Beagle 2 would end up leashed to a deployed PLUTO, and drag itself across the surface whilst trying to winch it in smile.gif
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RoverDriver
post May 12 2009, 08:23 PM
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QUOTE (lyford @ May 12 2009, 07:22 AM) *
Speaking of using the IDD for which is was not designed, could the arm reach down and push to help get out of the sandtrap as a last resort? biggrin.gif

(I am not serious, but I recall that Phoenix could at least theoretically dragged itself along with it's arm....)


Can't really do that. The motor controllers are shared between IDD and mobility. This means that while we drive we cannot move the IDD.

Paolo


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centsworth_II
post May 12 2009, 09:15 PM
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Maybe a self portrait would show how much daylight is between the rover and the ground?
Could the IDD look between Spirit's legs like the arm camera on Phoenix did?
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RoverDriver
post May 13 2009, 12:40 AM
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QUOTE (centsworth_II @ May 12 2009, 02:15 PM) *
Maybe a self portrait would show how much daylight is between the rover and the ground?
Could the IDD look between Spirit's legs like the arm camera on Phoenix did?


She could, but as I was saying in another thread, we momentarily cannot use the IDD on Spirit. If we really believe we need to take that MI shot, we will work on getting the IDD working again.

Paolo


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