Ardupilot Parameter Setup

Documentation is outdated.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

Ardupilot description of the parameters

Standard set of SearchWing ArduPilot parameters

Is the safety_mask maybe not required because the pixracer is always in safe state? Safe and disarmed is different?

Aktiviert die FrSky Telemetrie auf dem FrSky Port des Pixracers

Metadata consist of GPS / Timestamp

Several bits can be set for logging of different informations: Log Bitmask Description

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

• 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 Code). For the attitude two settings are available: Fast (50Hz), Medium(10Hz) according to LINK. I think 10Hz could be enough for us. But in the Code actually the Logging is done with 25Hz (see Code)
• IMU logging could be disabled, as its already triggerd by attitude logging anyway (see Code), but with less data amount. UPDATE: Actually IMU also loggs the BARO, so it should not be disabled (see 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 Log Bitmask Description):

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

  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
  
  

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

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.

(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.