diff --git a/docs/en/config/safety.md b/docs/en/config/safety.md index a01a6c6bb7..5640f1dcd7 100644 --- a/docs/en/config/safety.md +++ b/docs/en/config/safety.md @@ -207,7 +207,7 @@ The relevant parameters shown below. ### Position Loss Failsafe Action Multicopters will switch to [Altitude mode](../flight_modes_mc/altitude.md) if a height estimate is available, otherwise [Stabilized mode](../flight_modes_mc/manual_stabilized.md). - + Fixed-wing planes, and VTOLs not configured to land in hover ([NAV_FORCE_VT](../advanced_config/parameter_reference.md#NAV_FORCE_VT)), have a parameter ([FW_GPSF_LT](../advanced_config/parameter_reference.md#FW_GPSF_LT)) that defines how long they will loiter (circle with a constant roll angle ([FW_GPSF_R](../advanced_config/parameter_reference.md#FW_GPSF_R)) at the current altitude) after losing position before attempting to land. If VTOLs have are configured to switch to hover for landing ([NAV_FORCE_VT](../advanced_config/parameter_reference.md#NAV_FORCE_VT)) then they will first transition and then descend. @@ -276,12 +276,12 @@ The relevant parameters are listed in the table below. ## Failure Detector -The failure detector allows a vehicle to take protective action(s) if it unexpectedly flips, or if it is notified by an external failure detection system. +The failure detector allows a vehicle to take protective actions if it unexpectedly flips, detects a motor failure, or if it is notified by an external failure detection system. During **flight**, the failure detector can be used to trigger [flight termination](../advanced_config/flight_termination.md) if failure conditions are met, which may then launch a [parachute](../peripherals/parachute.md) or perform some other action. ::: info -Failure detection during flight is deactivated by default (enable by setting the parameter: [CBRK_FLIGHTTERM=0](#CBRK_FLIGHTTERM)). +Acting on a detected failure during flight is deactivated by default (enable by setting the parameter: [CBRK_FLIGHTTERM=0](#CBRK_FLIGHTTERM)). ::: During **takeoff** the failure detector [attitude trigger](#attitude-trigger) invokes the [disarm action](#act_disarm) if the vehicle flips (disarm kills the motors but, unlike flight termination, will not launch a parachute or perform other failure actions). @@ -303,6 +303,26 @@ The relevant parameters are shown below: | [FD_FAIL_P_TTRI](../advanced_config/parameter_reference.md#FD_FAIL_P_TTRI) | Time to exceed [FD_FAIL_P](#FD_FAIL_P) for failure detection (default 0.3s). | | [FD_FAIL_R_TTRI](../advanced_config/parameter_reference.md#FD_FAIL_R_TTRI) | Time to exceed [FD_FAIL_R](#FD_FAIL_R) for failure detection (default 0.3s). | +### Motor Failure Trigger + +The failure detector can be configured to detect a motor failure while armed (and trigger an associated action) in the following conditions: + +- A 300 ms timeout occurs in telemetry from an ESC that was previously available. +- The input current in the telemetry of an ESC which was previously positive gets too low for more than [`FD_ACT_MOT_TOUT`](FD_ACT_MOT_TOUT) ms. + The "too low" condition is defined by: + + ```text + {esc current} < {parameter FD_ACT_MOT_C2T} * {motor command between 0 and 1} + ``` + +| Parameter | Description | +| -------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | +| [FD_ACT_EN](../advanced_config/parameter_reference.md#FD_ACT_EN) | Enable/disable the motor failure trigger completely. | +| [FD_ACT_MOT_THR](../advanced_config/parameter_reference.md#FD_ACT_MOT_THR) | Minimum normalized [0,1] motor command below which motor under current is ignored. | +| [FD_ACT_MOT_C2T](../advanced_config/parameter_reference.md#FD_ACT_MOT_C2T) | Scale between normalized [0,1] motor command and expected minimally reported currrent when the rotor is healthy. | +| [FD_ACT_MOT_TOUT](../advanced_config/parameter_reference.md#FD_ACT_MOT_TOUT) | Time in miliseconds for which the under current detection condition needs to stay true. | +| [CA_FAILURE_MODE](../advanced_config/parameter_reference.md#CA_FAILURE_MODE) | Configure to not only warn about a motor failure but remove the first motor that detects a failure from the allocation effectiveness which turns off the motor and tries to operate the vehicle without it until disarming the next time. | + ### External Automatic Trigger System (ATS) The [failure detector](#failure-detector), if [enabled](#CBRK_FLIGHTTERM), can also be triggered by an external ATS system. diff --git a/docs/en/debug/failure_injection.md b/docs/en/debug/failure_injection.md index 217a2b7ffb..298e1aad50 100644 --- a/docs/en/debug/failure_injection.md +++ b/docs/en/debug/failure_injection.md @@ -19,7 +19,7 @@ At time of writing (PX4 v1.14): ## Failure System Command -Failures can be injected using the [failure system command](../modules/modules_command.md#failure) from any PX4 console/shell, specifying both the target and type of the failure. +Failures can be injected using the [failure system command](../modules/modules_command.md#failure) from any PX4 [console/shell](../debug/consoles.md) (such as the [QGC MAVLink Console](../debug/mavlink_shell.md#qgroundcontrol-mavlink-console) or SITL _pxh shell_), specifying both the target and type of the failure. ### Syntax @@ -61,12 +61,19 @@ where: - _instance number_ (optional): Instance number of affected sensor. 0 (default) indicates all sensors of specified type. -### Example +## MAVSDK Failure Plugin + +The [MAVSDK failure plugin](https://mavsdk.mavlink.io/main/en/cpp/api_reference/classmavsdk_1_1_failure.html) can be used to programmatically inject failures. +It is used in [PX4 Integration Testing](../test_and_ci/integration_testing_mavsdk.md) to simulate failure cases (for example, see [PX4-Autopilot/test/mavsdk_tests/autopilot_tester.cpp](https://github.com/PX4/PX4-Autopilot/blob/main/test/mavsdk_tests/autopilot_tester.cpp)). + +The plugin API is a direct mapping of the failure command shown above, with a few additional error signals related to the connection. + +## Example: RC signal To simulate losing RC signal without having to turn off your RC controller: -1. Enable the parameter [SYS_FAILURE_EN](../advanced_config/parameter_reference.md#SYS_FAILURE_EN). And specifically to turn off motors also [CA_FAILURE_MODE](../advanced_config/parameter_reference.md#CA_FAILURE_MODE). -1. Enter the following commands on the MAVLink console or SITL _pxh shell_: +1. Enable the [SYS_FAILURE_EN](../advanced_config/parameter_reference.md#SYS_FAILURE_EN) parameter. +2. Enter the following commands on the MAVLink console or SITL _pxh shell_: ```sh # Fail RC (turn publishing off) @@ -76,9 +83,18 @@ To simulate losing RC signal without having to turn off your RC controller: failure rc_signal ok ``` -## MAVSDK Failure Plugin +## Example: Motor -The [MAVSDK failure plugin](https://mavsdk.mavlink.io/main/en/cpp/api_reference/classmavsdk_1_1_failure.html) can be used to programmatically inject failures. -It is used in [PX4 Integration Testing](../test_and_ci/integration_testing_mavsdk.md) to simulate failure cases (for example, see [PX4-Autopilot/test/mavsdk_tests/autopilot_tester.cpp](https://github.com/PX4/PX4-Autopilot/blob/main/test/mavsdk_tests/autopilot_tester.cpp)). +To stop a motor mid-flight without the system anticipating it or excluding it from allocation effectiveness: -The plugin API is a direct mapping of the failure command shown above, with a few additional error signals related to the connection. +1. Enable the [SYS_FAILURE_EN](../advanced_config/parameter_reference.md#SYS_FAILURE_EN) parameter. +2. Enable [CA_FAILURE_MODE](../advanced_config/parameter_reference.md#CA_FAILURE_MODE) parameter to allow turning off motors. +3. Enter the following commands on the MAVLink console or SITL _pxh shell_: + + ```sh + # Turn off first motor + failure motor off -i 1 + + # Turn it back on + failure motor ok -i 1 + ```