Details
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Type:
Improvement
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Status: Done
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Resolution: Done
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Fix Version/s: None
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Component/s: ts_hardware, ts_main_telescope
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Labels:
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Story Points:0
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Epic Link:
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Sprint:TSSW Sprint - Aug 30 - Sep 13
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Team:Telescope and Site
Description
There is a software end-stop limit for the rotator that stops it if the rotator tries to go beyond 90 degrees.
Please look into the implementation of the software end-stop and see if you can apply it to how we stop the rotator when the CCW falls behind.
Attachments
Activity
For the track command, if the demanded position value is out of range (end-stop software limit), the command will be illegal:
https://github.com/lsst-ts/ts_rotator_controller/blob/develop/src/commanding.c#L261-L281
// tracking and slewing mode command |
case TRACK_VEL_CMD: |
if (!(isEnabled(state1))) { |
// printf("Rejected: must be enabled state\n"); // |
// 11OCT |
gLastCommandIllegal = 1;
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break; |
}
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// check for the target position being beyond allowed |
// position. |
if ((cmdMsg.param2 > |
rotatorCommands_signal.Parameters_upperPosLimit_deg) ||
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(cmdMsg.param2 <
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rotatorCommands_signal.Parameters_lowerPosLimit_deg)) {
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syslog(LOG_ERR, "TRACK_VEL target position exceeds range"); |
rotatorCommands_signal.Parameters_trackVel_rate_degPerSec =
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0.0;
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LsstCmdSet[2] = 0.0;
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gLastCommandIllegal = 1;
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break; |
}
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This is the similar case of POSITIONSET command.
In the simulink model, there is a subsystem: Limit_check_Bias_Calc. The positionFault will be 1 if the rotator angle is out of range.
This will write into rotatorTelemetry_signal.Flags_positionFeedbackFault. This will trigger the errorIsTrue in the state machine:
If the system is in the Enabled state and errorIsTrue is 1, the system will transition to the ControlledStopping state and stop the rotator's movement.
Based on the implementation, the rotator CSC is using the same mechanism of end-stop limit when the CCW falls behind. Both of them make use of the trigger of errorIsTrue = 1.0 and put the system into the ControlledStopping sub-state. Thanks!
Thanks, Te-Wei. This answers the question.
After the discussion with Holger, this ticket is to find the software behavior when the rotator arrives the end-stop software limit (90/-90 degree).