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Opportunity Route Map
Phil Stooke
post Apr 19 2018, 09:01 PM
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All Mars rovers have done pivots in place, leaving circular marks in their tracks. There are several in this view by Spirit at Engineering Flats in the fall of 2004:

https://mars.nasa.gov/mer/gallery/press/spi...-A252R1_br2.jpg

Phil



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RoverDriver
post Apr 20 2018, 11:56 AM
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QUOTE (HSchirmer @ Apr 19 2018, 11:26 AM) *
I'm assuming the Oppy outline is to scale, um, how does the rover execute the 180' turns?
Does it do some form N-point turn, or can it do a tank-style "piviot in place" manouver,
I ask because I don't recall ever seeing a circular pivot track.


The MER and MSL rovers are designed to do a point turn, that is, pivoting around the vehicle center (assuming flat terrain, no slip). This is done by setting the corner wheels toed in at about 60 deg and rotating the left wheels in the opposite direction relative to the right side wheels. We can also do (small) tank turns when we need to point the vehicle with extreme accuracy (better than 1 deg) to avoid the small vehicle motion when we straighten the wheels.

Alas Oppy now has TWO steering actuators that are inoperable so while we can still command a point turn, this results in a semi-tank-steer which we sometimes do but creates a lot of stress to the vehicle shaking it pretty violently. What we are left is what we call a spirograph turn, basically the 13-point turn you see being done by large SUVs in a small parking lot. This is even more difficult when you are on a 20 deg slope.

Paolo


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Phil Stooke
post Apr 22 2018, 04:08 PM
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A small move to the north on sol 5063.

Phil

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RoverDriver
post Apr 22 2018, 09:20 PM
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The Sol 5063 drive objective was to do a (almost) 180 while also backing up to leave some room to maneuver up the hill. I won't hod my breath but this vehicle has surprised me before.

Paolo


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Phil Stooke
post Apr 24 2018, 10:24 PM
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Made it! Nearly 10 m uphill on sol 5065.

Phil

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Phil Stooke
post Yesterday, 05:42 PM
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And now an adjustment to reach the next interesting vesicular target... about 2 m downhill and to the right, AKA roughly southeast.

Phil

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