Safety (Failsafe) Configuration
PX4에는 문제 발생시에 기체를 보호하고 복구하는 다양한 안전장치들을 제공합니다.
- Failsafes allow you to specify areas and conditions under which you can safely fly, and the action that will be performed if a failsafe is triggered (for example, landing, holding position, or returning to a specified point). The most important failsafe settings are configured in the QGroundControl Safety Setup page. Others must be configured via parameters.
- Safety switches on the remote control can be used to immediately stop motors or return the vehicle in the event of a problem.
QGroundControl 안전 설정
The QGroundControl Safety Setup page is accessed by clicking the QGroundControl icon, Vehicle Setup, and then Safety in the sidebar. This includes many of the most important failsafe settings (battery, RC loss etc.) and the settings for the triggered actions Return and Land.
안전장치 기능
When a failsafe is triggered, the default behavior (for most failsafes) is to enter Hold for COM_FAIL_ACT_T seconds before performing an associated failsafe action. This gives the user time to notice what is happening and override the failsafe if needed. In most cases this can be done by using RC or a GCS to switch modes (note that during the failsafe-hold, moving the RC sticks does not trigger an override).
The list below shows the set of all failsafe actions, ordered in increasing severity. Note that different types of failsafe may not support all of these actions.
| 동작 | 설명 |
|---|---|
| None/Disabled | No action. The failsafe will be ignored. |
| Warning | A warning message will be sent (i.e. to QGroundControl). |
| Hold mode | The vehicle will enter Hold mode (MC) or Hold mode (FW) and hover or circle, respectively. VTOL vehicles will hold according to their current mode (MC/FW). |
| Return mode | The vehicle will enter Return mode. Return behaviour can be set in the Return Home Settings (below). |
| Land mode | The vehicle will enter Land mode (MC) or Land mode (FW), and land. A VTOL will first transition to MC mode. |
| Disarm | Stops the motors immediately. |
| Flight termination | Turns off all controllers and sets all PWM outputs to their failsafe values (e.g. PWM_MAIN_FAILn, PWM_AUX_FAILn). 안전장치 출력은 낙하산, 랜딩 기어를 배치하거나 다른 작업을 수행할 수 있습니다. 고정익은 안전하게 활공할 수 있습니다. |
If multiple failsafes are triggered, the more severe action is taken. For example if both RC and GPS are lost, and manual control loss is set to Return mode and GCS link loss to Land, Land is executed.
TIP
The exact behavior when different failsafes are triggered can be tested with the Failsafe State Machine Simulation.
복귀 설정
Return is a common failsafe action that engages Return mode to return the vehicle to the home position. The default settings for each vehicle are usually suitable, though for fixed wing vehicles you will usually need to define a mission landing.
TIP
If you want to change the configuration you should carefully read the Return mode documentation for your vehicle type to understand the options.
QGC allows users to set some aspects of the return mode and landing behaviour, such as the altitude to fly back, and the loiter time if you need to deploy landing gear.
착륙 모드 설정
Land at the current position is a common failsafe action (in particular for multicopters), that engages Land Mode. The default settings for each vehicle are usually suitable.
TIP
If you want to change the configuration you should carefully read the Land mode documentation for your vehicle type to understand the options.
QGC allows users to set some aspects of the landing behaviour, such as the time to disarm after landing and the descent rate (for multicopters only).
Battery Failsafes
Battery level failsafe
The low battery failsafe is triggered when the battery capacity drops below battery failafe level values. You can configure both the levels and the failsafe actions at each level in QGroundControl.
The most common configuration is to set the values and action as above (with Warn > Failsafe > Emergency), and to set the Failsafe Action to warn at "warn level", trigger Return mode at "Failsafe level", and land immediately at "Emergency level".
설정에 관련된 기본 매개변수는 다음과 같습니다.
| 설정 | 매개변수 | 설명 |
|---|---|---|
| Failsafe Action | COM_LOW_BAT_ACT | Warn, Return, or Land based when capacity drops below the trigger levels. |
| Battery Warn Level | BAT_LOW_THR | 경고 (또는 기타 조치)에 대한 용량을 백분율로 설정합니다. |
| Battery Failsafe Level | BAT_CRIT_THR | 귀환 조치 (또는 단일 조치가 선택된 경우 다른 조치)에 대한 용량에 대한 백분율. |
| Battery Emergency Level | BAT_EMERGEN_THR | 즉시 착륙시의 용량의 백분율. |
Flight Time Failsafes
There are several other "battery related" failsafe mechanisms that may be configured using parameters:
- The "remaining flight time for safe return" failsafe (COM_FLTT_LOW_ACT) is engaged when PX4 estimates that the vehicle has just enough battery remaining for a return mode landing. You can configure this to ignore the failsafe, warn, or engage Return mode.
- The "maximum flight time failsafe" (COM_FLT_TIME_MAX) allows you to set a maximum flight time after takeoff, at which the vehicle will automatically enter return mode (it will also "warn" at 90% of this time). This is like a "hard coded" estimate of the total flight time in a battery. The feature is disabled by default.
- The "minimum battery" for arming parameter (COM_ARM_BAT_MIN) prevents arming in the first place if the battery level is below the specified value.
설정에 관련된 기본 매개변수는 다음과 같습니다.
| 설정 | 매개변수 | 설명 |
|---|---|---|
| Low flight time for safe return action | COM_FLTT_LOW_ACT | Action when return mode can only just reach safety with remaining battery. 0: None, 1: Warning, 3: Return mode (default). |
| Maximum flight time failsafe level | COM_FLT_TIME_MAX | Maximum allowed flight time before Return mode will be engaged, in seconds. -1: Disabled (default). |
Manual Control Loss Failsafe
The manual control loss failsafe may be triggered if the connection to the RC transmitter or joystick is lost, and there is no fallback. If using an RC transmitter this is triggered if the RC transmitter link is lost. If using joysticks connected over a MAVLink data link, this is triggered if the joysticks are disconnected or the data link is lost.
INFO
PX4 and the receiver may also need to be configured in order to detect RC loss: Radio Setup > RC Loss Detection.
The QGCroundControl Safety UI allows you to set the failsafe action and RC Loss timeout. Users that want to disable the RC loss failsafe in specific automatic modes (mission, hold, offboard) can do so using the parameter COM_RCL_EXCEPT.
Additional (and underlying) parameter settings are shown below.
| 매개변수 | 설정 | 설명 |
|---|---|---|
| COM_RC_LOSS_T | Manual Control Loss Timeout | Time after last setpoint received from the selected manual control source after which manual control is considered lost. This must be kept short because the vehicle will continue to fly using the old manual control setpoint until the timeout triggers. |
| COM_FAIL_ACT_T | Failsafe Reaction Delay | Delay in seconds between failsafe condition being triggered (COM_RC_LOSS_T) and failsafe action (RTL, Land, Hold). In this state the vehicle waits in hold mode for the manual control source to reconnect. This might be set longer for long-range flights so that intermittent connection loss doesn't immediately invoke the failsafe. It can be to zero so that the failsafe triggers immediately. |
| NAV_RCL_ACT | 안전장치 동작 | Disabled, Loiter, Return, Land, Disarm, Terminate. |
| COM_RCL_EXCEPT | RC 손실 예외 | Set the modes in which manual control loss is ignored: Mission, Hold, Offboard. |
데이터 연결불량 안전장치
The Data Link Loss failsafe is triggered if a telemetry link (connection to ground station) is lost.
설정에 관련된 기본 매개변수는 다음과 같습니다.
| 설정 | 매개변수 | 설명 |
|---|---|---|
| 데이터 연결불량 시간 초과 | COM_DL_LOSS_T | 데이터 연결이 끊어진 후 안전 장치가 동작하기 전까지의 시간입니다. |
| 안전장치 동작 | NAV_DLL_ACT | Disabled, Hold mode, Return mode, Land mode, Disarm, Terminate. |
다음 설정도 가능하지만 QGC UI에 표시되지 않습니다.
| 설정 | 매개변수 | 설명 |
|---|---|---|
| Mode exceptions for DLL failsafe | COM_DLL_EXCEPT | Set modes where DL loss will not trigger a failsafe. |
Geofence 안전장치
The Geofence Failsafe is triggered when the drone breaches a "virtual" perimeter. In its simplest form, the perimeter is set up as a cylinder centered around the home position. If the vehicle moves outside the radius or above the altitude the specified Failsafe Action will trigger.
TIP
PX4 separately supports more complicated Geofence geometries with multiple arbitrary polygonal and circular inclusion and exclusion areas: Flying > Geofence.
The settings and underlying geofence parameters are shown below.
| 설정 | 매개변수 | 설명 |
|---|---|---|
| GF_ACTION | 없음, 경고, 보류 모드, 반환 모드, 종료, 착륙. | |
| 최대 반경 | GF_MAX_HOR_DIST | 지오펜스 실린더의 수평 반경. 0 인 경우 지오펜스가 비활성화됩니다. |
| 최대 고도 | GF_MAX_VER_DIST | 지오펜스 실린더의 높이. 0 인 경우 지오펜스가 비활성화됩니다. |
INFO
Setting GF_ACTION to terminate will kill the vehicle on violation of the fence. Due to the inherent danger of this, this function is disabled using CBRK_FLIGHTTERM, which needs to be reset to 0 to really shut down the system.
다음 설정도 가능하지만 QGC UI에 표시되지 않습니다.
| 설정 | 매개변수 | 설명 |
|---|---|---|
| Geofence source | GF_SOURCE | 위치 소스가 글로벌 위치인지 또는 GPS 장치에서 직접 가져오는 지를 설정합니다. |
| Preemptive geofence triggering | GF_PREDICT | (Experimental) Trigger geofence if current motion of the vehicle is predicted to trigger the breach (rather than late triggering after the breach). |
| Circuit breaker for flight termination | CBRK_FLIGHTTERM | 비행 종료 작업을 활성화/비활성화합니다 (기본적으로 비활성화 됨). |
Position (GNSS) Loss Failsafe
The Position Loss Failsafe is triggered if the quality of the PX4 global position estimate falls below acceptable levels (this might be caused by GPS loss) while in a mode that requires an acceptable position estimate.
The failure action is controlled by COM_POSCTL_NAVL, based on whether RC control is assumed to be available (and altitude information):
0: Remote control available. Switch to Altitude mode if a height estimate is available, otherwise Stabilized mode.1: Remote control not available. Switch to Descend mode if a height estimate is available, otherwise enter flight termination. Descend mode is a landing mode that does not require a position estimate.
Fixed-wing planes, and VTOLs not configured to land in hover (NAV_FORCE_VT), have a parameter (FW_GPSF_LT) that defines how long they will loiter (circle with a constant roll angle (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) then they will first transition and then descend.
The relevant parameters for all vehicles shown below.
| 매개변수 | 설명 |
|---|---|
| COM_POSCTL_NAVL | Position control navigation loss response during mission. Values: 0 - assume use of RC, 1 - Assume no RC. |
Parameters that only affect Fixed-wing vehicles:
| 매개변수 | 설명 |
|---|---|
| FW_GPSF_LT | Loiter time (waiting for GPS recovery before it goes into land or flight termination). 비활성화 하려면 0으로 설정하십시오. |
| FW_GPSF_R | 선회 비행시 고정 롤/뱅크 각도. |
오프 보드 안전 장치
The Offboard Loss Failsafe is triggered if the offboard link is lost while under Offboard control. RC 연결을 사용 여부에 따라 다른 안전 장치의 작동을 지정할 수 있습니다.
관련된 매개 변수는 다음과 같습니다.
| 매개변수 | 설명 |
|---|---|
| COM_OF_LOSS_T | 오프 보드 단락이후 안전장치 동작 지연 여부 설정. |
| COM_OBL_RC_ACT | RC를 사용할 수있는 경우 비상 안전조치 : 위치 모드, 고도 모드, 수동 모드, 귀환 모드, 착륙 모드, 대기 모드. |
교통 회피 안전 장치
The Traffic Avoidance Failsafe allows PX4 to respond to transponder data (e.g. from ADSB transponders) during missions.
관련된 매개 변수는 다음과 같습니다.
| 매개변수 | 설명 |
|---|---|
| NAV_TRAFF_AVOID | 비상 안전 장치를 설정합니다 : 비활성화, 경고, 귀환 모드, 착륙 모드. |
Quad-chute Failsafe
Failsafe for when a VTOL vehicle can no longer fly in fixed-wing mode, perhaps due to the failure of a pusher motor, airspeed sensor, or control surface. If the failsafe is triggered, the vehicle will immediately switch to multicopter mode and execute the action defined in parameter COM_QC_ACT.
INFO
The quad-chute can also be triggered by sending a MAVLINK MAV_CMD_DO_VTOL_TRANSITION message with param2 set to 1.
The parameters that control when the quad-chute will trigger are listed in the table below.
| 매개변수 | 설명 |
|---|---|
| COM_QC_ACT | Quad-chute action after switching to multicopter flight. Can be set to: Warning, Return, Land, Hold. |
| VT_FW_QC_HMAX | Maximum quad-chute height, below which the quad-chute failsafe cannot trigger. This prevents high altitude quad-chute descent, which can drain the battery (and itself cause a crash). The height is relative to ground, home, or the local origin (in preference order, depending on what is available). |
| VT_QC_ALT_LOSS | Uncommanded descent quad-chute altitude threshold. In altitude controlled modes, such as Hold mode, Position mode, Altitude mode, or Mission mode, a vehicle should track its current "commanded" altitude setpoint. The quad chute failsafe is triggered if the vehicle falls too far below the commanded setpoint (by the amount defined in this parameter). Note that the quad-chute is only triggered if the vehicle continuously loses altitude below the commanded setpoint; it is not triggered if the commanded altitude setpoint increases faster than the vehicle can follow. |
| VT_QC_T_ALT_LOSS | Altitude loss threshold for quad-chute triggering during VTOL transition to fixed-wing flight. The quad-chute is triggered if the vehicle falls this far below its initial altitude before completing the transition. |
| VT_FW_MIN_ALT | Minimum altitude above Home for fixed-wing flight. When the altitude drops below this value in fixed-wing flight the vehicle a quad-chute is triggered. |
| VT_FW_QC_R | Absolute roll threshold for quad-chute triggering in FW mode. |
| VT_FW_QC_P | Absolute pitch threshold for quad-chute triggering in FW mode. |
High Wind Failsafe
The high wind failsafe can trigger a warning and/or other mode change when the wind speed exceeds the warning and maximum wind-speed threshhold values. The relevant parameters are listed in the table below.
| 매개변수 | 설명 |
|---|---|
| COM_WIND_MAX | Wind speed threshold that triggers failsafe action, in m/s (COM_WIND_MAX_ACT). |
| COM_WIND_MAX_ACT | High wind failsafe action (following COM_WIND_MAX trigger). Can be set to: 0: None (Default), 1: Warning, 2: Hold, 3: Return, 4: Terminate, 5: Land. |
| COM_WIND_WARN | Wind speed threshold that triggers periodic failsafe warning. |
고장 감지기
고장 감지기를 사용하여 차량의 예기치 않게 전복되거나 외부의 고장 감지 시스템에 따른 보호 조치를 할 수 있습니다.
During flight, the failure detector can be used to trigger flight termination if failure conditions are met, which may then launch a parachute or perform some other action.
INFO
Failure detection during flight is deactivated by default (enable by setting the parameter: CBRK_FLIGHTTERM=0).
During takeoff the failure detector attitude trigger invokes the disarm action if the vehicle flips (disarm kills the motors but, unlike flight termination, will not launch a parachute or perform other failure actions). Note that this check is always enabled on takeoff, irrespective of the CBRK_FLIGHTTERM parameter.
The failure detector is active in all vehicle types and modes, except for those where the vehicle is expected to do flips (i.e. Acro mode (MC), Acro mode (FW), and Manual (FW)).
자세 감지기
기체의 자세가 지정된 시간보다 오랫동안 사전 정의 된 피치 및 롤 값을 초과하는 경우 동작하도록 고장 감지기를 설정할 수 있습니다.
관련된 매개 변수는 다음과 같습니다.
| 매개변수 | 설명 |
|---|---|
| CBRK_FLIGHTTERM | 비행 종료 회로 차단기. 고장 감지기 또는 FMU 손실로 인한 비행 종료를 활성화하려면, 121212 (기본값)에서 설정을 해제합니다. |
| FD_FAIL_P | 최대 허용 피치 (도 단위). |
| FD_FAIL_R | 최대 허용 롤 (도 단위). |
| FD_FAIL_P_TTRI | Time to exceed FD_FAIL_P for failure detection (default 0.3s). |
| FD_FAIL_R_TTRI | Time to exceed FD_FAIL_R for failure detection (default 0.3s). |
외부 자동 작동 시스템 (ATS)
The failure detector, if enabled, can also be triggered by an external ATS system. 외부 작동 시스템은 비행 컨트롤러 포트 AUX5 (또는 AUX 포트가없는 보드의 MAIN5)에 연결되어야 하며 아래의 매개 변수들을 사용하여 설정합니다.
INFO
External ATS is required by ASTM F3322-18. One example of an ATS device is the FruityChutes Sentinel Automatic Trigger System.
| 매개변수 | 설명 |
|---|---|
| FD_EXT_ATS_EN | AUX5 또는 MAIN5 (보드에 따라 다름)에서 PWM 입력을 활성화하여 외부 자동 작동 시스템 (ATS)에서 안전 장치를 연결합니다. 기본값 : 비활성화 됨. |
| FD_EXT_ATS_TRIG | 안전장치 연결을 위한 외부 자동 작동 시스템의 PWM 임계치입니다. 기본값: 1900 ms. |
Mission Feasibility Checks
A number of checks are run to ensure that a mission can only be started if it is feasible. For example, the checks ensures that the first waypoint isn't too far away, and that the mission flight path doesn't conflict with any geofences.
As these are not strictly speaking "failsafes" they are documented in Mission Mode (FW) > Mission Feasibility Checks and Mission Mode (MC) > Mission Feasibility Checks.
비상 스위치
Remote control switches can be configured (as part of QGroundControl Flight Mode Setup) to allow you to take rapid corrective action in the event of a problem or emergency; for example, to stop all motors, or activate Return mode.
이 섹션에는 사용 가능한 비상 스위치에 대하여 설명합니다.
중지 스위치
A kill switch immediately stops all motor outputs — if flying, the vehicle will start to fall!
By default the motors will restart if the switch is reverted within 5 seconds, after which the vehicle will automatically disarm, and you will need to arm it again in order to start the motors.
| 매개변수 | 설명 |
|---|---|
| COM_KILL_DISARM | Timeout value for disarming after kill switch is engaged. Default: 5 seconds. |
INFO
There is also a Kill Gesture, which cannot be reverted.
시동/비시동 스위치
The arm/disarm switch is a direct replacement for the default stick-based arming/disarming mechanism (and serves the same purpose: making sure there is an intentional step involved before the motors start/stop). 다음과 같은 사유로 기본 메커니즘보다 우선적으로 사용될 수 있습니다.
- 스틱 동작보다 스위치를 선호합니다.
- 특정 스틱 동작으로 공중에서 실수로 시동/비시동 하는 것을 방지합니다.
- 지연 시간이 없습니다 (즉시 동작합니다).
The arm/disarm switch immediately disarms (stop) motors for those flight modes that support disarming in flight. 여기에는 다음의 항목들이 포함됩니다.
- Manual mode
- Acro mode
- Stabilized
비행중 비시동을 지원하지 않는 모드의 경우 비행 중 스위치가 무시되지만 착륙 후에 사용 가능합니다. This includes Position mode and autonomous modes (e.g. Mission, Land etc.).
INFO
Auto disarm timeouts (e.g. via COM_DISARM_LAND) are independent of the arm/disarm switch - ie even if the switch is armed the timeouts will still work.
귀환 스위치
A return switch can be used to immediately engage Return mode.
Kill Gesture
A kill gesture immediately stops all motor outputs — if flying, the vehicle will start to fall!
The action cannot be reverted without a reboot (this differs from a Kill Switch, where the operation can be reverted within the time period defined by COM_KILL_DISARM).
| 매개변수 | 설명 |
|---|---|
| MAN_KILL_GEST_T | Time to hold sticks in gesture position before killing the motors. Default: -1 seconds (Disabled). |
Arming/Disarming Settings
The commander module has a number of parameters prefixed with COM_ARM that configure whether the vehicle can arm at all, and under what conditions (note that some parameters named with the prefix COM_ARM are used to arm other systems). Parameters prefixed with COM_DISARM_ affect disarming behaviour.
Auto-Disarming Timeouts
이륙 속도가 너무 느리거나, 착륙 후 기체의 시동을 자동으로 꺼기 위하여 시간 제한을 설정할 수 있습니다(기체의 시동을 꺼면 모터의 전원이 제거되므로 프로펠러가 동작하지 않습니다).
The relevant parameters are shown below:
| 매개변수 | 설명 |
|---|---|
| COM_DISARM_LAND | 착륙후 자동 시동 꺼기 대기 시간 |
| COM_DISARM_PRFLT | 기체가 이륙이 너무 더딘 경우 자동 시동 꺼기 대기 시간 |
Arming Pre-Conditions
These parameters can be used to set conditions that prevent arming.
| 매개변수 | 설명 |
|---|---|
| COM_ARMABLE | Enable arming (at all). 0: Disabled, 1: Enabled (default). |
| COM_ARM_BAT_MIN | Minimum battery level for arming. 0: Disabled (default). Values: 0-0.9, |
| COM_ARM_WO_GPS | Enable arming without GPS. 0: Disabled, 1: Enabled (default). |
| COM_ARM_MIS_REQ | Require valid mission to arm. 0: Disabled (default), 1: Enabled . |
| COM_ARM_SDCARD | Require SD card to arm. 0: Disabled (default), 1: Warning, 2: Enabled. |
| COM_ARM_AUTH_REQ | Requires arm authorisation from an external (MAVLink) system. Flag to allow arming (at all). 1: Enabled, 0: Disabled (default). Associated configuration parameters are prefixed with COM_ARM_AUTH_. |
| COM_ARM_ODID | Require healthy Remote ID system to arm. 0: Disabled (default), 1: Warning, 2: Enabled. |
In addition there are a number of parameters that configure system and sensor limits that make prevent arming if exceeded: COM_CPU_MAX, COM_ARM_IMU_ACC, COM_ARM_IMU_GYR, COM_ARM_MAG_ANG, COM_ARM_MAG_STR.