# Modules Reference: System
battery_simulator <command> [arguments...] Commands: start stop status print status info
The provided functionality includes:
- Read the output from the ADC driver (via ioctl interface) and publish
It runs in its own thread and polls on the currently selected gyro topic.
battery_status <command> [arguments...] Commands: start stop status print status info
camera_feedback <command> [arguments...] Commands: start stop status print status info
The commander module contains the state machine for mode switching and failsafe behavior.
commander <command> [arguments...] Commands: start [-h] Enable HIL mode calibrate Run sensor calibration mag|baro|accel|gyro|level|esc|airspeed Calibration type quick Quick calibration (accel only, not recommended) check Run preflight checks arm [-f] Force arming (do not run preflight checks) disarm [-f] Force disarming (disarm in air) takeoff land transition VTOL transition mode Change flight mode manual|acro|offboard|stabilized|altctl|posctl|auto:mission|auto:loiter|auto :rtl|auto:takeoff|auto:land|auto:precland Flight mode pair lockdown on|off Turn lockdown on or off set_ekf_origin lat, lon, alt Origin Latitude, Longitude, Altitude lat|lon|alt Origin latitude longitude altitude poweroff Power off board (if supported) stop status print status info
Module to provide persistent storage for the rest of the system in form of a simple database through a C API. Multiple backends are supported:
- a file (eg. on the SD card)
- RAM (this is obviously not persistent)
It is used to store structured data of different types: mission waypoints, mission state and geofence polygons. Each type has a specific type and a fixed maximum amount of storage items, so that fast random access is possible.
Reading and writing a single item is always atomic. If multiple items need to be read/modified atomically, there is
an additional lock per item type via
DM_KEY_FENCE_POINTS and DM_KEY_SAFE_POINTS items: the first data element is a
which stores the number of items for these types. These items are always updated atomically in one transaction (from
the mavlink mission manager). During that time, navigator will try to acquire the geofence item lock, fail, and will not
check for geofence violations.
dataman <command> [arguments...] Commands: start [-f <val>] Storage file values: <file> [-r] Use RAM backend (NOT persistent) The options -f and -r are mutually exclusive. If nothing is specified, a file 'dataman' is used stop status print status info
Command-line tool to show bootup console messages. Note that output from NuttX's work queues and syslog are not captured.
Keep printing all messages in the background:
dmesg -f &
dmesg <command> [arguments...] Commands: [-f] Follow: wait for new messages
This implements using information from the ESC status and publish it as battery status.
esc_battery <command> [arguments...] Commands: start stop status print status info
Simple online gyroscope calibration.
gyro_calibration <command> [arguments...] Commands: start stop status print status info
gyro_fft <command> [arguments...] Commands: start stop status print status info
Background process running periodically on the LP work queue to regulate IMU temperature at a setpoint.
This task can be started at boot from the startup scripts by setting SENS_EN_THERMAL or via CLI.
heater <command> [arguments...] Commands: start stop status print status info
Module to detect the freefall and landed state of the vehicle, and publishing the
Each vehicle type (multirotor, fixedwing, vtol, ...) provides its own algorithm, taking into account various
states, such as commanded thrust, arming state and vehicle motion.
Every type is implemented in its own class with a common base class. The base class maintains a state (landed, maybe_landed, ground_contact). Each possible state is implemented in the derived classes. A hysteresis and a fixed priority of each internal state determines the actual land_detector state.
# Multicopter Land Detector
ground_contact: thrust setpoint and velocity in z-direction must be below a defined threshold for time GROUND_CONTACT_TRIGGER_TIME_US. When ground_contact is detected, the position controller turns off the thrust setpoint in body x and y.
maybe_landed: it requires ground_contact together with a tighter thrust setpoint threshold and no velocity in the horizontal direction. The trigger time is defined by MAYBE_LAND_TRIGGER_TIME. When maybe_landed is detected, the position controller sets the thrust setpoint to zero.
landed: it requires maybe_landed to be true for time LAND_DETECTOR_TRIGGER_TIME_US.
The module runs periodically on the HP work queue.
land_detector <command> [arguments...] Commands: start Start the background task fixedwing|multicopter|vtol|rover|airship Select vehicle type stop status print status info
Background process running periodically on the low priority work queue to calculate the CPU load and RAM
usage and publish the
On NuttX it also checks the stack usage of each process and if it falls below 300 bytes, a warning is output, which will also appear in the log file.
load_mon <command> [arguments...] Commands: start Start the background task stop status print status info
System logger which logs a configurable set of uORB topics and system printf messages
PX4_ERR) to ULog files. These can be used for system and flight performance evaluation,
tuning, replay and crash analysis.
It supports 2 backends:
- Files: write ULog files to the file system (SD card)
- MAVLink: stream ULog data via MAVLink to a client (the client must support this)
Both backends can be enabled and used at the same time.
The file backend supports 2 types of log files: full (the normal log) and a mission log. The mission log is a reduced ulog file and can be used for example for geotagging or vehicle management. It can be enabled and configured via SDLOG_MISSION parameter. The normal log is always a superset of the mission log.
The implementation uses two threads:
- The main thread, running at a fixed rate (or polling on a topic if started with -p) and checking for data updates
- The writer thread, writing data to the file
In between there is a write buffer with configurable size (and another fixed-size buffer for the mission log). It should be large to avoid dropouts.
Typical usage to start logging immediately:
logger start -e -t
Or if already running:
logger <command> [arguments...] Commands: start [-m <val>] Backend mode values: file|mavlink|all, default: all [-x] Enable/disable logging via Aux1 RC channel [-e] Enable logging right after start until disarm (otherwise only when armed) [-f] Log until shutdown (implies -e) [-t] Use date/time for naming log directories and files [-r <val>] Log rate in Hz, 0 means unlimited rate default: 280 [-b <val>] Log buffer size in KiB default: 12 [-p <val>] Poll on a topic instead of running with fixed rate (Log rate and topic intervals are ignored if this is set) values: <topic_name> [-c <val>] Log rate factor (higher is faster) default: 1.0 on start logging now, override arming (logger must be running) off stop logging now, override arming (logger must be running) stop status print status info
Online magnetometer bias estimator.
mag_bias_estimator <command> [arguments...] Commands: start Start the background task stop status print status info
Module consuming manual_control_inputs publishing one manual_control_setpoint.
manual_control <command> [arguments...] Commands: start stop status print status info
MicroDDS Client used to communicate uORB topics with an Agent over serial or UDP.
microdds_client start -t serial -d /dev/ttyS3 -b 921600 microdds_client start -t udp -h 127.0.0.1 -p 15555
microdds_client <command> [arguments...] Commands: start [-t <val>] Transport protocol values: serial|udp, default: udp [-d <val>] serial device values: <file:dev> [-b <val>] Baudrate (can also be p:<param_name>) default: 0 [-h <val>] Host IP values: <IP>, default: 127.0.0.1 [-p <val>] Remote Port default: 8888 [-l] Restrict to localhost (use in combination with ROS_LOCALHOST_ONLY=1) [-n <val>] Client DDS namespace stop status print status info
Network configuration manager saves the network settings in non-volatile
memory. On boot the
update option will be run. If a network configuration
does not exist. The default setting will be saved in non-volatile and the
On Subsequent boots, the
update option will check for the existence of
net.cfg in the root of the SD Card. It will saves the network settings
net.cfg in non-volatile memory, delete the file and reboot the system.
save option will
net.cfg on the SD Card. Use this to edit the settings.
show option will display the network settings to the console.
$ netman save # Save the parameters to the SD card. $ netman show # display current settings. $ netman update -i eth0 # do an update
netman <command> [arguments...] Commands: show Display the current persistent network settings to the console. update Check SD card for net.cfg and update network persistent network settings. save Save the current network parameters to the SD card. [-i <val>] Set the interface name default: eth0
Measures the PWM input on AUX5 (or MAIN5) via a timer capture ISR and publishes via the uORB 'pwm_input` message.
pwm_input <command> [arguments...] Commands: start stop status print status info
The rc_update module handles RC channel mapping: read the raw input channels (
then apply the calibration, map the RC channels to the configured channels & mode switches
and then publish as
To reduce control latency, the module is scheduled on input_rc publications.
rc_update <command> [arguments...] Commands: start stop status print status info
This module is used to replay ULog files.
There are 2 environment variables used for configuration:
replay, which must be set to an ULog file name - it's
the log file to be replayed. The second is the mode, specified via
replay_mode=ekf2: specific EKF2 replay mode. It can only be used with the ekf2 module, but allows the replay to run as fast as possible.
- Generic otherwise: this can be used to replay any module(s), but the replay will be done with the same speed as the log was recorded.
The module is typically used together with uORB publisher rules, to specify which messages should be replayed. The replay module will just publish all messages that are found in the log. It also applies the parameters from the log.
The replay procedure is documented on the System-wide Replay (opens new window) page.
replay <command> [arguments...] Commands: start Start replay, using log file from ENV variable 'replay' trystart Same as 'start', but silently exit if no log file given tryapplyparams Try to apply the parameters from the log file stop status print status info
Background process running periodically on the LP work queue to perform housekeeping tasks. It is currently only responsible for tone alarm on RC Loss.
The tasks can be started via CLI or uORB topics (vehicle_command from MAVLink, etc.).
send_event <command> [arguments...] Commands: start Start the background task stop status print status info
sensor_baro_sim <command> [arguments...] Commands: start stop status print status info
sensor_gps_sim <command> [arguments...] Commands: start stop status print status info
sensor_mag_sim <command> [arguments...] Commands: start stop status print status info
The sensors module is central to the whole system. It takes low-level output from drivers, turns it into a more usable form, and publishes it for the rest of the system.
The provided functionality includes:
- Read the output from the sensor drivers (
sensor_gyro, etc.). If there are multiple of the same type, do voting and failover handling. Then apply the board rotation and temperature calibration (if enabled). And finally publish the data; one of the topics is
sensor_combined, used by many parts of the system.
- Make sure the sensor drivers get the updated calibration parameters (scale & offset) when the parameters change or
on startup. The sensor drivers use the ioctl interface for parameter updates. For this to work properly, the
sensor drivers must already be running when
- Do sensor consistency checks and publish the
It runs in its own thread and polls on the currently selected gyro topic.
sensors <command> [arguments...] Commands: start [-h] Start in HIL mode stop status print status info
Driver for reading data from the Tattu 12S 16000mAh smart battery.
tattu_can <command> [arguments...] Commands: start stop status print status info
The temperature compensation module allows all of the gyro(s), accel(s), and baro(s) in the system to be temperature compensated. The module monitors the data coming from the sensors and updates the associated sensor_correction topic whenever a change in temperature is detected. The module can also be configured to perform the coeffecient calculation routine at next boot, which allows the thermal calibration coeffecients to be calculated while the vehicle undergoes a temperature cycle.
temperature_compensation <command> [arguments...] Commands: start Start the module, which monitors the sensors and updates the sensor_correction topic calibrate Run temperature calibration process [-g] calibrate the gyro [-a] calibrate the accel [-b] calibrate the baro (if none of these is given, all will be calibrated) stop status print status info
Command-line tool to control & test the (external) tunes.
Tunes are used to provide audible notification and warnings (e.g. when the system arms, gets position lock, etc.). The tool requires that a driver is running that can handle the tune_control uorb topic.
Information about the tune format and predefined system tunes can be found here: https://github.com/PX4/PX4-Autopilot/blob/main/src/lib/tunes/tune_definition.desc
Play system tune #2:
tune_control play -t 2
tune_control <command> [arguments...] Commands: play Play system tune or single note. error Play error tune [-t <val>] Play predefined system tune default: 1 [-f <val>] Frequency of note in Hz (0-22kHz) [-d <val>] Duration of note in us [-s <val>] Volume level (loudness) of the note (0-100) default: 40 [-m <val>] Melody in string form values: <string> - e.g. "MFT200e8a8a" libtest Test library stop Stop playback (use for repeated tunes)
Command-line tool to show work queue status.
work_queue <command> [arguments...] Commands: start stop status print status info