searchwing-ardupilot-parameters [Digitale Elektronik und Technische Informatik]

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====== Ardupilot Parameter Setup ======

**Documentation is outdated. Please take a look at the standard SearchWing configuration in the searchwing-config git.**

[[https://ardupilot.org/plane/docs/parameters-Plane-stable-V4.2.0.html|Ardupilot description of the parameters]]

[[https://gitlab.com/searchwing/operational/searchwing-config/-/blob/master/ardupilot/searchwing/LATEST.params|Standard set of SearchWing ArduPilot parameters]]

==== Arming / Safety ====

^Parametername      ^Value       ^Description                 ^Remark                       ^
|BRD_SAFETYENABLE   |0           |Disable the safety switch   |Safety switch is not accessible, because it is inside the fuselage |
|ARMING_RUDDER      |2           |Arm and Disarm with rudder  |Default is that you can only arm but not disarm with rudder |
|BRD_SAFETY_MASK    |27          |Servo 1,2,4,5 enabled       |These servos can move also in safe state - NOT REQUIRED??? |
|INS_GYRO_CAL       |0           |Disable Gyro Calibration at startup       | This prevents INS calibration at startup|
|ARSPD_TYPE         |0           |No Airspeed Pitot Tube      | Disable the Pitottube airspeed sensor (we don't have one)|
|COMPASS_USE2       |0           |Disable PixRacer compass    | Disable the PixRacer internal compass |
|COMPASS_USE3       |0           |Disable PixRacer compass    | Disable the PixRacer internal compass |
Is the safety_mask maybe not required because the pixracer is always in safe state? Safe and disarmed is different?

==== Servo settings ====

^Parametername      ^Value       ^Description                 ^Remark  ^
|SERVO1_FUNCTION    |4           | Aileron left                | |
|SERVO1_REVERSED    |1           | Reverse the servo           | |
|SERVO2_FUNCTION    |79          | VTAIL left                  | |
|SERVO2_REVERSED    |0           | Normal                      | |
|SERVO3_FUNCTION    |70          | Throttle                    | |
|SERVO3_REVERSED    |0           | Reverse the servo           | |
|SERVO4_FUNCTION    |80          | VTAIL right                 | |
|SERVO4_REVERSED    |1           | Reverse servo               | |
|SERVO5_FUNCTION    |4           | Aileron right                | |
|SERVO5_REVERSED    |1           | Reversed                    | |
^Servo ranges for servo 1,2,4,5 (aileron and vtail) ||||
|SERVOx_MIN         |1000        | Minimum servo value         | Default is 1100 - too high |
|SERVOx_MAX         |2000        | Maximum servo value         | Default is 1900 - too low |  
|SERVOx_TRIM        |1500        | Default value               | Leitwerk mitte |    
^Servo ranges for throttle ||||
|SERVO3_MIN         |900         | Minimum servo value         | CHECK THIS!!! Maybe 950 to be able to arm|
|SERVO3_MAX         |2000        | Maximum servo value         | Default is 1900 - too low | 
|SERVO3_TRIM        |900         | Default value               | zero throttle |    

==== Servo/PID Controller ====

^Parametername      ^Value       ^Description                 ^Remark  ^
|MIXING_GAIN        |0.75        |Mixing of pitch and rudder to vtail |Default is 0.5 - full pitch will yield only 50 percent of vtail servo output |


===== FrSky Telemetrie =====

^Parametername      ^Value       ^Description                 ^Remark  ^
|SERIAL4_BAUD       |57          |57600 Baud |  |
|SERIAL4_PROTOCOL   |10          |FrSky SPort Passthrough (OpenTX) | Format for the FrSyk Telemetry |

Aktiviert die FrSky Telemetrie auf dem FrSky Port des Pixracers


===== PI Zero Telemetry for image metadata =====

Metadata consist of  GPS / Timestamp

^Parametername      ^Value       ^Description                 ^Remark  ^
|SERIAL2_BAUD       |9           |9600 Baud |reduced to 9600 as otherwise no wifi with MAVESP connection possible |
|SERIAL2_PROTOCOL   |2           |MAVLink2 | Mavlink2 needed for PLAY_TUNE |
|SR2_RAW_SENS       |0           |0 Hz |no raw data needed |
|SR2_EXT_STAT       |1           |1 Hz | |
|SR2_RC_CHAN        |0           |0 Hz | |
|SR2_RAW_CTRL       |0           |0 Hz | |
|SR2_POSITION       |5           |5 Hz | Contains GLOBAL_POSITION_INT, LOCAL_POSITION_NED messages |
|SR2_EXTRA1       |5           |5 Hz | Contains ATTITUDE message |
|SR2_EXTRA2       |0           |0 Hz |  |
|SR2_EXTRA3       |1           |1 Hz | Contains SYSTEM_TIME message |
|SR2_PARAMS       |0           |0 Hz |  |
|SR2_ADSB         |0           |0 Hz | |


===== Logging =====

Several bits can be set for logging of different informations: [[https://ardupilot.org/plane/docs/parameters.html#log-bitmask-log-bitmask|Log Bitmask Description]]

Enabled all (''==65535'') results in following per message data sum in bytes for a 20 minute flight:

{{ ::average_log_msg_sizes.png?1400 |}}

  * The PID, NKF(EKF) and IMU take a lot of space.
  * The PID and EKF is saved using the "attitude" bit in the logging parameter setting (see [[https://github.com/ArduPilot/ardupilot/blob/6af0f460afa6f51c41056cd25fe2c70164d9d460/ArduPlane/Log.cpp#L39|Code]]). For the attitude two settings are available: Fast (50Hz), Medium(10Hz) according to [[https://github.com/ArduPilot/ardupilot_wiki/blob/6c81c28126e6cb2bdbb9cb58291342ca3ade96a0/dev/source/docs/using-the-command-line-interpreter-to-configure-apmcopter.rst#reading-logs-through-the-cli|LINK]]. I think 10Hz could be enough for us. __**But in the Code actually the Logging is done with 25Hz**__ (see [[https://github.com/ArduPilot/ardupilot/blob/d8d3494b170d50f7b45dced928cd5d9150b50d2f/ArduPlane/ArduPlane.cpp#L87|Code]])
  * IMU logging **could be disabled,** as its already triggerd by attitude logging anyway (see [[https://github.com/ArduPilot/ardupilot/blob/d8d3494b170d50f7b45dced928cd5d9150b50d2f/ArduPlane/ArduPlane.cpp#L209|Code]]), but with less data amount. **UPDATE:** Actually IMU also loggs the **BARO**, so it should not be disabled (see [[https://github.com/ArduPilot/ardupilot/search?q=set_log_baro_bit|INFO]].
  * TECS (Total Energy Control System) controls altitude vs speed and is important and **should be enabled**.
  * CTUN Logs contain baro and ** should be enabled.**
  * NTUN Logs navigation tuning info at 10 Hz and ** should  be enabled.**

This results in the following Table (according to [[https://ardupilot.org/plane/docs/parameters.html#log-bitmask-log-bitmask|Log Bitmask Description]]):

^ Bit 	^ Meaning    ^ Enabled ^
| 0 | ATTITUDE_FAST(50Hz) | OFF |
| 1 | ATTITUDE_MED(10Hz) | ON |
| 2 | GPS | ON |
| 3 | PM | ON |
| 4 | CTUN | ON |
| 5 | NTUN | ON |
| 6 | MODE | ON |
| 7 | IMU | ON |
| 8 | CMD | ON |
| 9 | CURRENT | ON |
| 10 | COMPASS | ON |
| 11 | TECS | ON |
| 12 | CAMERA | OFF |
| 13 | RC | ON |
| 14 | SONAR | OFF |
| 15 | ARM/DISARM | ON |
| 19 | IMU_RAW | OFF |
| 20 | ATTITUDE_FULLRATE | OFF |

This results into the following parameter values. In the remarks you can see empirical Results for some settings from ArduPlane Simulator.

^Parametername      ^Value       ^Description                 ^Remark  ^
|LOG_BITMASK       |  65535          | Log all    |     ~3.04 MB/Min Log          |
|LOG_BITMASK       |  45054          | Log from table above (IMU disabled) |     TODO       |
|LOG_BITMASK       |  TODO          | Log from table above (IMU enabled) |     TODO        |
|LOG_BITMASK       |  2              | Log only attitude Medium |     ~1.75 MB/Min Log         |


===== MAVESP8266 Wifi Telemetry =====

^Parametername      ^Value       ^Description                 ^Remark  ^
|SERIAL5_BAUD       |921           |921600 Baud |  |
|SERIAL5_PROTOCOL   |2           |MAVLink2 |   |

===== Power Module =====


    1	1	BATT_AMP_PERVLT	24.0	9
    1	1	BATT_AMP_OFFSET	-0.07	9
    1	1	BATT_CURR_PIN	3	2
    1	1	BATT_MONITOR	4	2
    1	1	BATT_SERIAL_NUM	-1	6
    1	1	BATT_VOLT_MULT	10.213	9
    1	1	BATT_VOLT_PIN	2	2
    1	1	BATT_WATT_MAX	0	4
    
    
===== RPM =====

To measure the RPM of the motor we can use a BACK-EMF Measurement from 2 of the 3 motorcables. For more info check out the page:

https://www.hobbywingdirect.com/products/rpm-sensor

We connected the output pins to a AUX pin of the FC. Check out the info from Ardupilot for some info regarding the following config:

https://ardupilot.org/copter/docs/common-rpm.html


^Parametername      ^Value       ^Description                 ^Remark  ^
|RPM_MAX	|100000.000000000000000000	| | |
|RPM_MIN	|10.000000000000000000	| | |
|RPM_MIN_QUAL	|0.100000001490116119	| | |
|RPM_PIN	|Pin	| PIN | depending on FC |
|RPM_SCALING	|0.143	|  | check the hints below for this setting |
|RPM_TYPE	|2	| AUX | Type needs to be AUX to calc using the given sensor |

The RPM in general can be calculated using the formula from https://www.radiocontrolinfo.com/brushless-motor-efficiency/measuring-motor-rpm/ :

''RPM = ( 120 x Frequency ) / # of Motor Poles''

Thats because:

''The AC current that is produced alternates each time 2 magnetic poles pass by a winding in the stator.
''

As Ardupilot measures the periode duration ''dt_avg'' of the sensor rectangular signal, and calculates the RPM using

''float rpm = scaling * (1.0e6 / dt_avg) * 60;''

the scaling needs to correct this using

''SCALING = ( 1 / # of Motor Poles ) * 2''

For the Extron 800KV Motor , we have 14 Poles.

===== Tuning =====


 (David, Mülli, Simon)

    1	1	ARSPD_FBW_MAX	28	4
    1	1	ARSPD_FBW_MIN	12	4

Min and max airspeed - default 22 / 9

    1	1	LIM_PITCH_MAX	3000	4
    1	1	LIM_PITCH_MIN	-2000	4

default 2000, -2500

    1	1	MIN_GNDSPD_CM	800	6

If min groundspeed is net met, plane increases throttle

    1	1	NAVL1_DAMPING	0.800000023841857910	9	
    1	1	NAVL1_PERIOD	17.000000000000000000	9

This is the default value for NAVL1 (Beck, 27.2.20)

    1	1	PTCH2SRV_RLL	1.299999952316284180	9

This parameter controls how much elevator to add in turns to keep the nose level. Many aircraft require a small change to this parameter from the default of 1.0. (autotune)

    1	1	TECS_CLMB_MAX	6.500000000000000000	9
    1	1	TECS_SINK_MAX	5.000000000000000000	9


    1	1	WP_LOITER_RAD	60	4	
    1	1	WP_RADIUS	90	4

WP settings are set to default (Beck, 27.2.20)

# Modes Setup (Special Switches)

to be done.