Post Solar Conjunction/Santorini Study Drive

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Post Solar Conjunction/Santorini Study Drive, The second leg in our Journey to Endeavor Crater

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RoverDriver View Member Profile	Jan 11 2009, 03:32 PM Post #61
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200	QUOTE (nprev @ Jan 10 2009, 03:49 PM) Paolo, what's the anticipated work-around for the encoder loss? I assume it's used just for position monitoring telemetry, not for active positional feedback in the control loop? We believe that the loss of RAT grind and revolve encoders are due to damage to the flex cable of the IDD. The damage is presumably due to wear caused by friction and/or thermal cycles. Since the next trace was the RAT Z position encoder we did a test that was aimed at correlating the RAT Z position to particular values of voltage and time. Therefore the workaround is very similar to the revolve and grind actuators: disable the encoder and stall detection, and apply a predefined voltage for a fixed time assuming the actuator will move for an approximate amount. Careful monitoring of the motors current should allow to determine when interaction with the rock occurs. The sequence will allow for a large inaccuracy in position knowledge, but should nonetheless work. Since the keyword here is "should" we need to test it first on Earth before attempting its execution on Mars. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.

nprev View Member Profile	Jan 12 2009, 01:06 AM Post #62
Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602	Open-loop operation based on operational experience; got it, thanks, Paolo! More curiosity: I'm assuming that you guys built a table of the observed RAT-Z position vs. applied motor voltage/time. What sort of angular resolution did you get within your confidence/comfort level? Has the motor response changed over time as well? (I'm also assuming that it's still pretty linear, though). A lot of these engineering details are pure gold for future mission designs given the MERs' longevity. EDIT: Oops, think I meant something like 'distance resolution' instead of 'angular resolution': the Z-axis is forward/back, right? -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.

RoverDriver View Member Profile	Jan 12 2009, 09:04 AM Post #63
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200	QUOTE (nprev @ Jan 11 2009, 05:06 PM) Open-loop operation based on operational experience; got it, thanks, Paolo! More curiosity: I'm assuming that you guys built a table of the observed RAT-Z position vs. applied motor voltage/time. What sort of angular resolution did you get within your confidence/comfort level? Has the motor response changed over time as well? (I'm also assuming that it's still pretty linear, though). A lot of these engineering details are pure gold for future mission designs given the MERs' longevity. EDIT: Oops, think I meant something like 'distance resolution' instead of 'angular resolution': the Z-axis is forward/back, right? As I was saying we did it pretty recently (in the Sol 1600s I think) for the first time. It might be that Honeybee had done it during development or ATLO, but I don't think we monitored this particular behavior. I do not recall exactly the test, but I believe we measured the response for ~1mm RAT_Z travel assuming the response being linear with voltage (= speed) and time. I'm afriaid this is all the details I have for the moment. Yes, MER is an engineering mine, one aspect of this mission that has not been pointed out too often! Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.

SFJCody View Member Profile	Jan 13 2009, 09:33 PM Post #64
Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12	QUOTE sol 1768 Actual number of EDRs by sequence number and image type: Sol Seq.Ver ETH ESF EDN EFF ERP Tot Description ----- -------- --- --- --- --- --- ---- ----------- 01768 p1148.03 0 0 0 0 0 0 front_hazcam_rat_doc_right_eye_4bpp_pri_17 01768 p1148.03 0 0 0 0 0 0 front_hazcam_rat_doc_right_eye_4bpp_pri_17 01768 p1148.03 0 0 0 0 0 0 front_hazcam_rat_doc_right_eye_4bpp_pri_17 01768 p1154.01 0 0 0 0 0 0 front_hazcam_idd_unstow_doc 01768 p2138.09 0 0 0 0 0 0 pancam_RAT_diagnostic_R1 01768 p2138.09 0 0 0 0 0 0 pancam_RAT_diagnostic_R1 01768 p2138.09 0 0 0 0 0 0 pancam_RAT_diagnostic_R1 01768 p2138.09 0 0 0 0 0 0 pancam_RAT_diagnostic_R1 01768 p2536.22 0 0 0 0 0 0 pancam_superres_corsica_L26R12 01768 p2600.12 0 0 0 0 0 0 pancam_tau 01768 p2633.02 0 0 0 0 0 0 pancam_late_tau_L58R48 01768 Total 0 0 0 0 0 0 No driving to-sol it seems. More diagnostics.

RoverDriver View Member Profile	Jan 13 2009, 11:52 PM Post #65
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200	QUOTE (SFJCody @ Jan 13 2009, 01:33 PM) No driving to-sol it seems. More diagnostics. Correct. We need to retract the RAT-Z before driving. Last time we did not succeed, so we try and try again ;-) This time it should work. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.

CosmicRocker View Member Profile	Jan 15 2009, 06:26 AM Post #66
Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116	QUOTE (RoverDriver @ Jan 13 2009, 05:52 PM) Correct. We need to retract the RAT-Z before driving. Last time we did not succeed, so we try and try again ;-) This time it should work. ... In today's download I noticed a sequence of 4 pancams which appeared to show an extension followed by a retraction of the RAT along what I assume is the Z axis direction. It took place on sol 1768 over a period of about 6 minutes shortly before local noon. Was that the result we were hoping to see? -------------------- ...Tom I'm not a Space Fan, I'm a Space Exploration Enthusiast.

RoverDriver View Member Profile	Jan 15 2009, 05:26 PM Post #67
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200	QUOTE (CosmicRocker @ Jan 14 2009, 10:26 PM) In today's download I noticed a sequence of 4 pancams which appeared to show an extension followed by a retraction of the RAT along what I assume is the Z axis direction. It took place on sol 1768 over a period of about 6 minutes shortly before local noon. Was that the result we were hoping to see? Not entirely. The initial extension was not expected, at least not to me which I am not an expert on the RAT flight software. Still the retraction maneuver was successful so we are good to go to drive. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.

Nirgal View Member Profile	Jan 15 2009, 07:08 PM Post #68
Member Group: Members Posts: 713 Joined: 30-March 05 Member No.: 223	Thanks a lot for your prompt updates, Paolo ... those are well appreciated QUOTE (RoverDriver @ Jan 15 2009, 06:26 PM) so we are good to go to drive. -> Yeah ! Next stop: Endeavour Crater

RoverDriver View Member Profile	Jan 15 2009, 07:17 PM Post #69
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200	QUOTE (Nirgal @ Jan 15 2009, 11:08 AM) ...-> Yeah ! Next stop: Endeavour Crater I'm sure we will stumble into some cobbles along the way and deploy the IDD which now should be renamed Increasing Delay Device. (for those without sense of humor I mean: ) Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.

brellis View Member Profile	Jan 15 2009, 07:27 PM Post #70
Member Group: Members Posts: 754 Joined: 9-February 07 Member No.: 1700	Is the robotic arm still extended?

RoverDriver View Member Profile	Jan 15 2009, 08:05 PM Post #71
Member Group: Admin Posts: 976 Joined: 29-September 06 From: Pasadena, CA - USA Member No.: 1200	QUOTE (brellis @ Jan 15 2009, 11:27 AM) Is the robotic arm still extended? I'm not sure what you mean by "extended". We no longer do the regular IDD stow on MER-B. We keep it like an elephant's trunk, dangling in front of the hazcams, sort of like a carrot to run faster. If you were asking if the IDD is still in the the same position during the RAT-Z tests, I believe the answer is yes. We will be "stowing" the IDD right before the next drive. Paolo -------------------- Disclaimer: all opinions, ideas and information included here are my own,and should not be intended to represent opinion or policy of my employer.

Tesheiner View Member Profile	Jan 15 2009, 09:26 PM Post #72
Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253	QUOTE (RoverDriver @ Jan 15 2009, 06:26 PM) ... we are good to go to drive. Yeah! I really like these words.

Nirgal View Member Profile	Jan 15 2009, 09:53 PM Post #73
Member Group: Members Posts: 713 Joined: 30-March 05 Member No.: 223	QUOTE (RoverDriver @ Jan 15 2009, 09:05 PM) We keep it like an elephant's trunk, dangling in front of the hazcams, sort of like a carrot to run faster. Paolo LOL

CosmicRocker View Member Profile	Jan 16 2009, 05:35 AM Post #74
Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116	I'll second that laugh, Nirgal. The 'carrot on a stick' is a metaphor we can all appreciate as Opportunity embarks on her latest colossal endeavor. It's a good thing the carrot is dangling in front of the hazcams, rather than the elevated navcams. -------------------- ...Tom I'm not a Space Fan, I'm a Space Exploration Enthusiast.

Tesheiner View Member Profile	Jan 16 2009, 01:04 PM Post #75
Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253	... and Opportunity has finally left Santorini's vicinity during sol 1770. There are still very few images from the new site (fhaz, rhaz, nav), not enough (for me) to determine the new position, but I would say we are near the southern end of the "Conjunction Road".

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