Mission command timeout #3495
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Mission command timeout #3495
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hamishwillee
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Dec 12, 2024
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| ## Gimbal Control in Missions | ||
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| [Gimbal Manager commands](https://mavlink.io/en/services/gimbal_v2.html#gimbal-manager-messages) may be used in missions if supported by the vehicle type. | ||
| For example [MAV_CMD_DO_GIMBAL_MANAGER_PITCHYAW](https://mavlink.io/en/messages/common.html#MAV_CMD_DO_GIMBAL_MANAGER_PITCHYAW) is supported in [multicopter mission mode](../flight_modes_mc/mission.md). | ||
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| In theory you can address commands to a particular gimbal, specifying its component id using the "Gimbal device id" parameter. | ||
| However at time of writing (December 2024) this is [not supported](https://github.com/PX4/PX4-Autopilot/blob/main/src/modules/gimbal/input_mavlink.cpp#L889): all commands are sent to the gimbal with id [MAV_COMP_ID_GIMBAL (154)](https://mavlink.io/en/messages/common.html#MAV_COMP_ID_GIMBAL) | ||
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| Gimbal movement is not immediate. | ||
| To ensure that the gimbal has time to move into position before the mission progresses to the next item (if gimbal feedback is not provided or lost), you should set [MIS_COMMAND_TOUT](../advanced_config/parameter_reference.md#MIS_COMMAND_TOUT) to be greater than the time taken for the gimbal to traverse its full range. | ||
| After this timeout the mission will proceed to the next item. |
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@julianoes Is this accurate? Specifically, my assumption is that all gimbal commands are sent to MAV_COMP_ID_GIMBAL but I couldn't find where.
hamishwillee
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Dec 12, 2024
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| ## Mission Command Timeouts | ||
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| Some mission commands/items can take time to complete, such as a gripper opening and closing, a winch extending or retracting, or a gimbal moving to point at a region of interest. | ||
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| Where provided PX4 may use sensor feedback from the hardware to determine when the action has completed and then move to the next mission item. | ||
| If not provided, or if the feedback is lost, a mission command timeout can be used to ensure that these kinds of actions will progress to the next mission item rather than blocking progression. | ||
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| The timeout is set using the [MIS_COMMAND_TOUT](../advanced_config/parameter_reference.md#MIS_COMMAND_TOUT) parameter. | ||
| This should be set to be a small amount greater than the time required for the longest long-running action in the mission to complete. |
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Note, add this to all the vehicle mission mode sections.
hamishwillee
commented
Dec 12, 2024
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No flaws found |
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This pull request has been mentioned on Discussion Forum for PX4, Pixhawk, QGroundControl, MAVSDK, MAVLink. There might be relevant details there: https://discuss.px4.io/t/params-since-v1-15-20241204/42717/1 |
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Some hardware can take time to reach the state commanded by a corresponding mission item, such as gimbals, grippers, winches.
Ideally you'd trigger transition to the next step on feedback from a sensor on the hardware, but many grippers etc don't have that, and in any case it is possible you will miss it. So for grippers the
MIS_PD_TOtimeout was created - it basically ensures that if you miss feedback (or if there is none) the mission will wait this amount of time before progressing.PX4/PX4-Autopilot#23960 renames
MIS_PD_TOwithMIS_COMMAND_TOUT, which applies to all of these long running mission items - it also uses this delay to give the gimbal time to move into position on a mission item.This provides the corresponding docs.