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  1. Data Management
  2. DM-25441

Remove the History of Trajectory after the Stop Command in the Tracking

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      Description

      Remove the history of trajectory after issuing the stop command in the tracking. The Simulink model uses the LsstCmdSet object to get the time, position, and velocity of tracking target. If the user issues the stop command before the finish of slew, the rotator stops without the update of LsstCmdSet. This means if the user issues the trackStart command, the rotator will transition to the SlewingAndTracking sub-state and try to track the unfinished target based on LsstCmdSet.

      In the following figure, there are two targets: (1) position=1.2 deg, velocity=0.01 deg/sec, and (2) position=3.0 deg, velocity=-0.01 deg/sec. The final track command is at time=6.05 second. Issue the stop command at time=7 second and trackStart command at time=9 second. We can see the rotator tries to finish the second target after it is back to the SlewingAndTracking sub-state.

      To solve this problem, we need to update the LsstCmdSet object to set the position to be the rotator's position or position command, and the velocity to be 0 after the stop completes (Flags_stopComplete ==1.0) as the following:

      There are four possible options to do this:
      (1) Update the LsstCmdSet object in ts_rotator_controller once Flags_stopComplete==1.0.
      (2) Let ts_rotator update the LsstCmdSet object by sending the new track command once Flags_stopComplete==1.0. However, we prefer to use the command acknowledgement to know the stop command is finished or not in a latter time.
      (3) Add a reset command or something similar in ts_rotator and ts_rotator_controller to let the rotator controller updates the position and velocity of LsstCmdSet.
      (4) Update the Simulink model to add a latch to determine when to use the new track command. This will add the complexity to the Simulink model because it is not designed in that way originally. It may not be easy to debug in a latter time. However, this will not affect the ts_rotator and ts_rotator_controller at all.

      I do not prefer the option 1 because there will be multiple places to write the data into the global variable of LsstCmdSet. Originally, it is updated by ts_rotator only. Or more accurately, the ts_rotator issues the track command to update the LsstCmdSet in commanding.c in ts_rotator_controller. If the option 1 is chosen, I need to let the actuator.c to be able to update the LsstCmdSet object. Think more deeply, for the option 3, it is the same thing. The only benefit for option 3 is that the CSC user knows the LsstCmdSet is changed. But if the CSC user does not care about this, maybe the option 1, 2, or 4 is better. If we consider the coherence of code, maybe the option 1 or 4 is the best solution.

        Attachments

        1. magnification.png
          magnification.png
          137 kB
        2. testResetMemory.png
          testResetMemory.png
          102 kB
        3. trackStopBeforeSlewDone.png
          trackStopBeforeSlewDone.png
          56 kB
        4. trackStopInitNew.png
          trackStopInitNew.png
          66 kB
        5. trackStopNewTarget.png
          trackStopNewTarget.png
          79 kB
        6. trackStopPosTrack.png
          trackStopPosTrack.png
          86 kB
        7. trackStopWithLatch.png
          trackStopWithLatch.png
          66 kB
        8. trackWithStopAnd3rdTargetOfPosNowAndRewiteCmdPosAndVel.png
          trackWithStopAnd3rdTargetOfPosNowAndRewiteCmdPosAndVel.png
          63 kB

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            ttsai Te-Wei Tsai added a comment - - edited

            Simulate the rotator to track 3 targets that have the positions of 1.2, 3.0, and 2.1 degree individually. Issue the stop command when the rotator is slewing to the second target at time=7 second, and the rotator stops at position=1.8 degree. At time=9 second, issue the trackStart command followed by the track command of the third target. Stop the track command of the third target in the slewing. After the slew is done, the rotator will be put into the Fault state because there is no new track command within 0.25 seconds (= 5 times of track command). The result is:

            This shows the rotator has no previous unfinished tracking history anymore.

            Notice the magnification region:

            When the rotator is put back to SlewingAndTracking substate and do not have the new track command yet, the CommandGenerator_ReceivedCmd telemetry will be the rotator's position at that time instead of the unfinished slew target.

            Show
            ttsai Te-Wei Tsai added a comment - - edited Simulate the rotator to track 3 targets that have the positions of 1.2, 3.0, and 2.1 degree individually. Issue the stop  command when the rotator is slewing to the second target at time=7 second, and the rotator stops at position=1.8 degree. At time=9 second, issue the trackStart  command followed by the track  command of the third target. Stop the track  command of the third target in the slewing. After the slew is done, the rotator will be put into the Fault  state because there is no new track  command within 0.25 seconds (= 5 times of track  command). The result is: This shows the rotator has no previous unfinished tracking history anymore. Notice the magnification region: When the rotator is put back to SlewingAndTracking  substate and do not have the new track  command yet, the CommandGenerator_ReceivedCmd  telemetry will be the rotator's position at that time instead of the unfinished slew target.
            Hide
            ttsai Te-Wei Tsai added a comment -

            Simulation the rotator to track 2 targets that have the position of 1.2 and 2.1 degree. Before the finish of the first slew, issue the stop command at time=2 second. The rotator stops at 0.75 degree. Use the positionSet command to set the target position of 1.5 degree. Put the rotator back to SlewingAndTracking substate at time=8 second. The rotator slews to the second target, and enters Fault state because there is no new track command. The figure is in the following:

            Show
            ttsai Te-Wei Tsai added a comment - Simulation the rotator to track 2 targets that have the position of 1.2 and 2.1 degree. Before the finish of the first slew, issue the stop  command at time=2 second. The rotator stops at 0.75 degree. Use the positionSet command to set the target position of 1.5 degree. Put the rotator back to SlewingAndTracking  substate at time=8 second. The rotator slews to the second target, and enters Fault  state because there is no new track  command. The figure is in the following:
            Hide
            ttsai Te-Wei Tsai added a comment - - edited

            Consider the constVelComplete tag in 'updatePosAndVelCmd' subsystem. Create the test manager of rotator Simulink model and add the test of 'isNewCommandReceived' subsystem.

            I realized the support of constVelComplete will fail at this moment because the Simulink uses the "goto" tag now. Give up this at this moment. Create another ticket (DM-25771) to support this.

            Show
            ttsai Te-Wei Tsai added a comment - - edited Consider the constVelComplete tag in 'updatePosAndVelCmd' subsystem. Create the test manager of rotator Simulink model and add the test of 'isNewCommandReceived' subsystem. I realized the support of constVelComplete will fail at this moment because the Simulink uses the "goto" tag now. Give up this at this moment. Create another ticket ( DM-25771 ) to support this.
            Hide
            ttsai Te-Wei Tsai added a comment -

            Please help to review the following PRs:
            1. https://github.com/lsst-ts/ts_mt_hexRot_simulink/pull/9
            2. https://github.com/lsst-ts/ts_rotator_controller/pull/7

            You may need to do the review based on the comment. Or I could go through the update with you. Thanks!

            Show
            ttsai Te-Wei Tsai added a comment - Please help to review the following PRs: 1.  https://github.com/lsst-ts/ts_mt_hexRot_simulink/pull/9 2.  https://github.com/lsst-ts/ts_rotator_controller/pull/7 You may need to do the review based on the comment. Or I could go through the update with you. Thanks!
            Hide
            rowen Russell Owen added a comment -

            Approved based on your description and test results. Thank you for fixing this nasty problem.

            Show
            rowen Russell Owen added a comment - Approved based on your description and test results. Thank you for fixing this nasty problem.

              People

              Assignee:
              ttsai Te-Wei Tsai
              Reporter:
              ttsai Te-Wei Tsai
              Reviewers:
              Russell Owen
              Watchers:
              Russell Owen, Te-Wei Tsai
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