Flight Physics
Inertial Measurement Unit (IMU)
The IMU provides data about the quadcopterâs orientation, movement, and position by combining gyroscopes, accelerometers, and magnetometers.
INS_GYRO_FILTER
26 Hz
Smooths gyro noise; a higher value reduces responsiveness but helps prevent oscillations. Lower values increase responsiveness but may allow noise.
INS_ACCEL_FILTER
10 Hz
Smooths accelerometer data; adjusting affects the responsiveness to tilt changes.
INS_USE
1
Enables IMU for flight control. If set to 0, the IMU inputs are ignored.
INS_ACCEL_OFFS_X, Y, Z
(calibrated values)
Stores offsets for calibrated accelerometer readings. Ensures accurate positioning.
INS_GYROFFS_X, Y, Z
(calibrated values)
Stores offsets for calibrated gyro readings. Minimizes drift and ensures stability.
MEAS Barometer
The barometer measures atmospheric pressure to estimate altitude. It plays a crucial role in altitude hold and flight stability.
BARO_PRESS
(pressure reading)
Displays the current pressure reading from the barometer.
BARO_ENABLE
1
Enables the barometer for altitude estimation. Set to 0 to disable.
BARO_GND_ALT
0
Sets the ground altitude for altitude calibration. This can be adjusted based on local altitude.
AHRS_USE_BARO
1
Enables the use of barometric data for altitude estimation in navigation calculations.
GPS Module
GPS is essential for navigation, position hold, and maintaining altitude during flight.
GPS_TYPE
1
Defines the type of GPS module used (e.g., u-blox).
GPS_AUTO_CONFIG
1
Enables automatic configuration of GPS parameters.
GPS_MINIMUM_HDOP
1.5
Sets the maximum horizontal dilution of precision for reliable GPS data.
Compass
The compass provides heading information, allowing the quadcopter to maintain its direction during flight. It is particularly important for navigation and orientation, especially when GPS is unavailable or unreliable.
COMPASS_ENABLE
1
Enables the onboard compass. Set to 0 to disable.
COMPASS_TYPEMASK
0
Determines which compass to use (e.g., 1 for internal, 2 for external).
COMPASS_OFS_X, Y, Z
(calibrated values)
Stores offsets for the compass readings to account for magnetic interference. Proper calibration is essential for accurate heading.
COMPASS_LEARN
1
Enables compass learning, allowing the system to improve its accuracy over time by adjusting to magnetic anomalies.
COMPASS_USE
1
Enables the compass for navigation. Set to 0 to ignore compass inputs.
COMPASS_PRIMARY
1
Specifies which compass to use as the primary source if multiple compasses are available.
COMPASS_CAL
1
Enables automatic compass calibration during flight.
RC Control and Receiver
The RC control system allows the pilot to communicate with the quadcopter for manual and automatic control.
RCMAP
0 1 2 3
Maps channels for throttle, roll, pitch, and yaw. Adjust based on your transmitter configuration.
RC_OPTIONS
0
Sets standard RC options. Modify if you need to change behavior.
Motors and Electronic Speed Controllers (ESCs)
Motors and ESCs are responsible for generating thrust and maneuverability.
MOT_PWM_TYPE
1
Sets motor control type (e.g., PWM). Ensure compatibility with your ESCs.
MOT_THST_HOVER
0.5
Sets the throttle level required to maintain hover. Adjust based on your quad's weight and performance.
MOT_SPIN_ARM
1
Allows motors to spin up when armed. Be cautious with this setting for safety.
Battery Monitoring
Proper battery management is critical for flight safety and preventing damage from over-discharge or over-charge.
BATT_VOLT_MIN
10.5 V
Sets the minimum battery voltage to avoid damaging the battery (for a 3S LiPo).
BATT_VOLT_MAX
12.6 V
Sets the maximum battery voltage to prevent overcharging.
BATT_CURR_MAX
30
Sets the maximum current draw, protecting the battery from excessive discharge.
Flight Modes
Different flight modes allow the quadcopter to perform various tasks, from manual control to autonomous missions.
FLTMODE
3
Sets the default flight mode (e.g., Stabilize, AltHold, Loiter).
FLTMODE2, FLTMODE3
Adjust based on preference
Configures additional flight modes as needed.
Fail-safes and Safety Features
Fail-safes ensure the quadcopter can safely respond to issues like loss of signal or low battery.
FS_THR_VALUE
975
Defines the throttle threshold for triggering fail-safe.
FS_GCS_ENABLE
1
Enables fail-safe if communication with the ground control station is lost.
Tuning Parameters (PID Control)
Fine-tuning PID values is essential for ensuring stable and responsive flight characteristics.
ATC_RAT_PIT_P
0.15
Controls pitch responsiveness. Increase for faster response; decrease if oscillations occur.
ATC_RAT_PIT_I
0.05
Integral gain for pitch; helps eliminate steady-state error. Adjust carefully to avoid instability.
ATC_RAT_PIT_D
0.03
Derivative gain for pitch; dampens oscillations. Increase for smoother flight; decrease if overshoot occurs.
ATC_RAT_RLL_P
0.15
Controls roll responsiveness, similar to pitch.
ATC_RAT_RLL_I
0.05
Integral gain for roll.
ATC_RAT_RLL_D
0.03
Derivative gain for roll.
ATC_RAT_YAW_P
0.2
Controls yaw responsiveness. Adjust similarly based on performance.
ATC_RAT_YAW_I
0.1
Integral gain for yaw.
ATC_RAT_YAW_D
0.05
Derivative gain for yaw.
Altitude Control Parameters
PSC_ACCZ_P
0.3
Controls altitude responsiveness; increase for faster altitude changes but ensure stability.
PSC_ACCZ_I
0.1
Integral gain for altitude; helps eliminate steady-state error.
Advanced IMU Parameters
AHRS_EKF_TYPE
3
Specifies which type of sensor fusion algorithm to use for estimating position and orientation. EKF2 is common and robust.
AHRS_YAW_P
0.15
Proportional gain for yaw in the EKF; adjust based on response.
Summary of Key Parameters
IMU
INS_GYRO_FILTER
26 Hz
Filters gyro noise.
INS_ACCEL_FILTER
10 Hz
Smooths accelerometer data.
GPS
GPS_TYPE
1
Defines GPS module type.
GPS_AUTO_CONFIG
1
Enables automatic GPS configuration.
RC Control
RCMAP
0 1 2 3
Maps channels for control inputs.
Motors/ESCs
MOT_PWM_TYPE
1
Sets motor control type.
MOT_THST_HOVER
0.5
Sets hover throttle level.
Battery
BATT_VOLT_MIN
10.5 V
Minimum battery voltage.
BATT_VOLT_MAX
12.6 V
Maximum battery voltage.
Flight Modes
FLTMODE
3
Default flight mode.
Fail-safes
FS_THR_VALUE
975
Throttle threshold for fail-safe.
Tuning
ATC_RAT_PIT_P
0.15
Pitch control responsiveness.
ATC_RAT_RLL_P
0.15
Roll control responsiveness.
Altitude Control
PSC_ACCZ_P
0.3
Altitude control responsiveness.
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