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* Add vitepress tree * Update existing workflows so they dont trigger on changes in the docs path * Add nojekyll, package.json, LICENCE etc * Add crowdin docs upload/download scripts * Add docs flaw checker workflows * Used docs prefix for docs workflows * Crowdin obvious fixes * ci: docs move to self hosted runner runs on a beefy server for faster builds Signed-off-by: Ramon Roche <mrpollo@gmail.com> * ci: don't run build action for docs or ci changes Signed-off-by: Ramon Roche <mrpollo@gmail.com> * ci: update runners Signed-off-by: Ramon Roche <mrpollo@gmail.com> * Add docs/en * Add docs assets and scripts * Fix up editlinks to point to PX4 sources * Download just the translations that are supported * Add translation sources for zh, uk, ko * Update latest tranlsation and uorb graphs * update vitepress to latest --------- Signed-off-by: Ramon Roche <mrpollo@gmail.com> Co-authored-by: Ramon Roche <mrpollo@gmail.com>
This commit is contained in:
Hamish Willee
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docs/en/advanced_config/prearm_arm_disarm.md
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docs/en/advanced_config/prearm_arm_disarm.md
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# Arm, Disarm, Prearm Configuration
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Vehicles may have moving parts, some of which are potentially dangerous when powered (in particular motors and propellers)!
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To reduce the chance of accidents, PX4 has explicit state(s) for powering the vehicle components:
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- **Disarmed:** There is no power to motors or actuators.
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- **Pre-armed:** Motors/propellers are locked but actuators for non-dangerous electronics are powered (e.g. ailerons, flaps etc.).
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- **Armed:** Vehicle is fully powered. Motors/propellers may be turning (dangerous!)
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::: info
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Ground stations may display _disarmed_ for pre-armed vehicles.
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While not technically correct for pre-armed vehicles, it is "safe".
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:::
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Users can control progression though these states using a [safety switch](../getting_started/px4_basic_concepts.md#safety-switch) on the vehicle (optional) _and_ an [arming switch/button](#arm_disarm_switch), [arming gesture](#arm_disarm_gestures), or _MAVLink command_ on the ground controller:
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- A _safety switch_ is a control _on the vehicle_ that must be engaged before the vehicle can be armed, and which may also prevent prearming (depending on the configuration).
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Commonly the safety switch is integrated into a GPS unit, but it may also be a separate physical component.
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:::warning
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A vehicle that is armed is potentially dangerous.
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The safety switch is an additional mechanism that prevents arming from happening by accident.
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:::
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- An _arming switch_ is a switch or button _on an RC controller_ that can be used to arm the vehicle and start motors (provided arming is not prevented by a safety switch).
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- An _arming gesture_ is a stick movement _on an RC controller_ that can be used as an alternative to an arming switch.
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- MAVLink commands can also be sent by a ground control station to arm/disarm a vehicle.
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PX4 will also automatically disarm the vehicle if it does not takeoff within a certain amount of time after arming, and if it is not manually disarmed after landing.
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This reduces the amount of time where an armed (and therefore dangerous) vehicle is on the ground.
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PX4 allows you to configure how pre-arming, arming and disarming work using parameters (which can be edited in _QGroundControl_ via the [parameter editor](../advanced_config/parameters.md)), as described in the following sections.
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:::tip
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Arming/disarming parameters can be found in [Parameter Reference > Commander](../advanced_config/parameter_reference.md#commander) (search for `COM_ARM_*` and `COM_DISARM_*`).
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:::
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## Arming/Disarming Gestures {#arm_disarm_gestures}
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By default, the vehicle is armed and disarmed by moving RC throttle/yaw sticks to particular extremes and holding them for 1 second.
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- **Arming:** Throttle minimum, yaw maximum
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- **Disarming:** Throttle minimum, yaw minimum
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RC controllers will use different sticks for throttle and yaw [based on their mode](../getting_started/rc_transmitter_receiver.md#types-of-remote-controllers), and hence different gestures:
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- **Mode 2**:
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- _Arm:_ Left stick to bottom right.
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- _Disarm:_ Left stick to the bottom left.
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- **Mode 1**:
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- _Arm:_ Left-stick to right, right-stick to bottom.
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- _Disarm:_ Left-stick to left, right-stick to the bottom.
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The required hold time can be configured using [COM_RC_ARM_HYST](#COM_RC_ARM_HYST).
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Note that by default ([COM_DISARM_MAN](#COM_DISARM_MAN)) you can also disarm in flight using gestures/buttons: you may choose to disable this to avoid accidental disarming.
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| Parameter | Description |
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| -------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------- |
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| <a id="MAN_ARM_GESTURE"></a>[MAN_ARM_GESTURE](../advanced_config/parameter_reference.md#MAN_ARM_GESTURE) | Enable arm/disarm stick guesture. `0`: Disabled, `1`: Enabled (default). |
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| <a id="COM_DISARM_MAN"></a>[COM_DISARM_MAN](../advanced_config/parameter_reference.md#COM_DISARM_MAN) | Enable disarming in flight via switch/stick/button in MC manual thrust modes. `0`: Disabled, `1`: Enabled (default). |
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| <a id="COM_RC_ARM_HYST"></a>[COM_RC_ARM_HYST](../advanced_config/parameter_reference.md#COM_RC_ARM_HYST) | Time that RC stick must be held in arm/disarm position before arming/disarming occurs (default: `1` second). |
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## Arming Button/Switch {#arm_disarm_switch}
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An _arming button_ or "momentary switch" can be configured to trigger arm/disarm _instead_ of [gesture-based arming](#arm_disarm_gestures) (setting an arming switch disables arming gestures).
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The button should be held down for ([nominally](#COM_RC_ARM_HYST)) one second to arm (when disarmed) or disarm (when armed).
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A two-position switch can also be used for arming/disarming, where the respective arm/disarm commands are sent on switch _transitions_.
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:::tip
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Two-position arming switches are primarily used in/recommended for racing drones.
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:::
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The switch or button is assigned (and enabled) using [RC_MAP_ARM_SW](#RC_MAP_ARM_SW), and the switch "type" is configured using [COM_ARM_SWISBTN](#COM_ARM_SWISBTN).
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| Parameter | Description |
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| -------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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| <a id="RC_MAP_ARM_SW"></a>[RC_MAP_ARM_SW](../advanced_config/parameter_reference.md#RC_MAP_ARM_SW) | RC arm switch channel (default: 0 - unassigned). If defined, the specified RC channel (button/switch) is used for arming instead of a stick gesture. <br>**Note:**<br>- This setting _disables the stick gesture_!<br>- This setting applies to RC controllers. It does not apply to Joystick controllers that are connected via _QGroundControl_. |
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| <a id="COM_ARM_SWISBTN"></a>[COM_ARM_SWISBTN](../advanced_config/parameter_reference.md#COM_ARM_SWISBTN) | Arm switch is a momentary button. <br>- `0`: Arm switch is a 2-position switch where arm/disarm commands are sent on switch transitions.<br>-`1`: Arm switch is a button or momentary button where the arm/disarm command ae sent after holding down button for set time ([COM_RC_ARM_HYST](#COM_RC_ARM_HYST)). |
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::: info
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The switch can also be set as part of _QGroundControl_ [Flight Mode](../config/flight_mode.md) configuration.
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:::
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## Auto-Disarming
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By default vehicles will automatically disarm on landing, or if you take too long to take off after arming.
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The feature is configured using the following timeouts.
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| Parameter | Description |
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| ----------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------- |
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| <a id="COM_DISARM_LAND"></a>[COM_DISARM_LAND](../advanced_config/parameter_reference.md#COM_DISARM_LAND) | Time-out for auto disarm after landing. Default: 2s (-1 to disable). |
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| <a id="COM_DISARM_PRFLT"></a>[COM_DISARM_PRFLT](../advanced_config/parameter_reference.md#COM_DISARM_PRFLT) | Time-out for auto disarm if too slow to takeoff. Default: 10s (<=0 to disable). |
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## Pre-Arm Checks
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To reduce accidents, vehicles are only allowed to arm certain conditions are met (some of which are configurable).
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Arming is prevented if:
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- The vehicle is not in a "healthy" state.
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For example it is not calibrated, or is reporting sensor errors.
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- The vehicle has a [safety switch](../getting_started/px4_basic_concepts.md#safety-switch) that has not been engaged.
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- The vehicle has a [remote ID](../peripherals/remote_id.md) that is unhealthy or otherwise not ready
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- A VTOL vehicle is in fixed-wing mode ([by default](../advanced_config/parameter_reference.md#CBRK_VTOLARMING)).
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- The current mode requires an adequate global position estimate but the vehicle does not have GPS lock.
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- Many more (see [arming/disarming safety settings](../config/safety.md#arming-disarming-settings) for more information).
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The current failed checks can be viewed in QGroundControl (v4.2.0 and later) [Arming Check Report](../flying/pre_flight_checks.md#qgc-arming-check-report) (see also [Fly View > Arming and Preflight Checks](https://docs.qgroundcontrol.com/master/en/qgc-user-guide/fly_view/fly_view.md#arm)).
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Note that internally PX4 runs arming checks at 10Hz.
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A list of the failed checks is kept, and if the list changes PX4 emits the current list using the [Events interface](../concept/events_interface.md).
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The list is also sent out when the GCS connects.
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Effectively the GCS knows the status of prearm checks immediately, both when disarmed and armed.
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:::details Implementation notes for developers
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The client implementation is in [libevents](https://github.com/mavlink/libevents):
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- [libevents > Event groups](https://github.com/mavlink/libevents#event-groups)
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- [health_and_arming_checks.h](https://github.com/mavlink/libevents/blob/main/libs/cpp/parse/health_and_arming_checks.h)
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QGC implementation: [HealthAndArmingCheckReport.cc](https://github.com/mavlink/qgroundcontrol/blob/master/src/MAVLink/LibEvents/HealthAndArmingCheckReport.cc).
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:::
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PX4 also emits a subset of the arming check information in the [SYS_STATUS](https://mavlink.io/en/messages/common.html#SYS_STATUS) message (see [MAV_SYS_STATUS_SENSOR](https://mavlink.io/en/messages/common.html#MAV_SYS_STATUS_SENSOR)).
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## Arming Sequence: Pre Arm Mode & Safety Button
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The arming sequence depends on whether or not there is a _safety switch_, and is controlled by the parameters [COM_PREARM_MODE](#COM_PREARM_MODE) (Prearm mode) and [CBRK_IO_SAFETY](#CBRK_IO_SAFETY) (I/O safety circuit breaker).
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The [COM_PREARM_MODE](#COM_PREARM_MODE) parameter defines when/if pre-arm mode is enabled ("safe"/non-throttling actuators are able to move):
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- _Disabled_: Pre-arm mode disabled (there is no stage where only "safe"/non-throttling actuators are enabled).
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- _Safety Switch_ (Default): The pre-arm mode is enabled by the safety switch.
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If there is no safety switch then pre-arm mode will not be enabled.
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- _Always_: Prearm mode is enabled from power up.
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If there is a safety switch then this will be a precondition for arming.
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If there is no safety switch the I/O safety circuit breaker must be engaged ([CBRK_IO_SAFETY](#CBRK_IO_SAFETY)), and arming will depend only on the arm command.
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The sections below detail the startup sequences for the different configurations
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### Default: COM_PREARM_MODE=Safety and Safety Switch
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The default configuration uses safety switch to prearm.
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From prearm you can then arm to engage all motors/actuators.
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It corresponds to: [COM_PREARM_MODE=1](#COM_PREARM_MODE) (safety switch) and [CBRK_IO_SAFETY=0](#CBRK_IO_SAFETY) (I/O safety circuit breaker disabled).
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The default startup sequence is:
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1. Power-up.
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- All actuators locked into disarmed position
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- Not possible to arm.
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1. Safety switch is pressed.
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- System now prearmed: non-throttling actuators can move (e.g. ailerons).
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- System safety is off: Arming possible.
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1. Arm command is issued.
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- The system is armed.
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- All motors and actuators can move.
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### COM_PREARM_MODE=Disabled and Safety Switch
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When prearm mode is _Disabled_, engaging the safety switch does not unlock the "safe" actuators, though it does allow you to then arm the vehicle.
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This corresponds to [COM_PREARM_MODE=0](#COM_PREARM_MODE) (Disabled) and [CBRK_IO_SAFETY=0](#CBRK_IO_SAFETY) (I/O safety circuit breaker disabled).
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The startup sequence is:
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1. Power-up.
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- All actuators locked into disarmed position
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- Not possible to arm.
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1. Safety switch is pressed.
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- _All actuators stay locked into disarmed position (same as disarmed)._
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- System safety is off: Arming possible.
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1. Arm command is issued.
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- The system is armed.
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- All motors and actuators can move.
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### COM_PREARM_MODE=Always and Safety Switch
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When prearm mode is _Always_, prearm mode is enabled from power up.
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To arm, you still need the safety switch.
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This corresponds to [COM_PREARM_MODE=2](#COM_PREARM_MODE) (Always) and [CBRK_IO_SAFETY=0](#CBRK_IO_SAFETY) (I/O safety circuit breaker disabled).
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The startup sequence is:
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1. Power-up.
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- System now prearmed: non-throttling actuators can move (e.g. ailerons).
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- Not possible to arm.
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1. Safety switch is pressed.
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- System safety is off: Arming possible.
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1. Arm command is issued.
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- The system is armed.
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- All motors and actuators can move.
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### COM_PREARM_MODE=Safety or Disabled and No Safety Switch
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With no safety switch, when `COM_PREARM_MODE` is set to _Safety_ or _Disabled_ prearm mode cannot be enabled (same as disarmed).
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This corresponds to [COM_PREARM_MODE=0 or 1](#COM_PREARM_MODE) (Disabled/Safety Switch) and [CBRK_IO_SAFETY=22027](#CBRK_IO_SAFETY) (I/O safety circuit breaker engaged).
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The startup sequence is:
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1. Power-up.
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- All actuators locked into disarmed position
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- System safety is off: Arming possible.
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1. Arm command is issued.
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- The system is armed.
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- All motors and actuators can move.
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### COM_PREARM_MODE=Always and No Safety Switch
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When prearm mode is _Always_, prearm mode is enabled from power up.
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This corresponds to [COM_PREARM_MODE=2](#COM_PREARM_MODE) (Always) and [CBRK_IO_SAFETY=22027](#CBRK_IO_SAFETY) (I/O safety circuit breaker engaged).
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The startup sequence is:
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1. Power-up.
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- System now prearmed: non-throttling actuators can move (e.g. ailerons).
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- System safety is off: Arming possible.
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1. Arm command is issued.
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- The system is armed.
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- All motors and actuators can move.
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### Parameters
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| Parameter | Description |
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| -------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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| <a id="COM_PREARM_MODE"></a>[COM_PREARM_MODE](../advanced_config/parameter_reference.md#COM_PREARM_MODE) | Condition to enter prearmed mode. `0`: Disabled, `1`: Safety switch (prearm mode enabled by safety switch; if no switch present cannot be enabled), `2`: Always (prearm mode enabled from power up). Default: `1` (safety button). |
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| <a id="CBRK_IO_SAFETY"></a>[CBRK_IO_SAFETY](../advanced_config/parameter_reference.md#CBRK_IO_SAFETY) | Circuit breaker for IO safety. |
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<!-- Discussion:
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https://github.com/PX4/PX4-Autopilot/pull/12806#discussion_r318337567
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https://github.com/PX4/PX4-user_guide/issues/567#issue-486653048
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-->
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