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Basic Tuning - PID Parameter
Set Up Advanced Failsafe
Configuration Optional
Hardware – Power Module Optional Hardware – SiK Telemetry Radio Optional Hardware – Airspeed
Sensor Optional Hardware - Camera Gimbal – Servo Controlled
Autopilot ConfigurationMission PlannerInstall Mission Planner using instructions here. Reference http://ardupilot.org/plane/docs/common-install-mission-planner.html#run-the-installation-utility On PC tgs005, connect to the pixhawk via USB using COM 3 with baud rate 57600. Mission Planner Installation Record.
Pixhawk FirmwareLoad the Arduplane firmware into the pixhawk using instructions here. Reference http://ardupilot.org/plane/docs/common-loading-firmware-onto-pixhawk.html Arduplane Firmware Installation Record.
Changes from Arduplane 3.7 to 3.8For reference to changes between Auduplane versions 3.7 and 3.8 refer here. - For servo and elevon set up, refer here. - Manual control of the control surfaces were checked and confirmed OK. - Control surface movement in FBWA mode was checked and confirmed to be OK. - After changing to v3.8, the analog airspeed sensor ARSPD_TYPE is confirmed as 2. - THR_MAX confirmed to still be 100%. Taranis Radio Set UpReference “Taranis Radio Set Up” at http://rcadev.info/OpenTX%2055%20Application%20Note%2026.htm Refer here for description of how I have set up the Taranis radio. ESC CalibrationReference http://ardupilot.org/plane/docs/guide-esc-calibration.html#guide-esc-calibration The ESC I use is a Turnigy Plush 40A To calibrate the ESC, I connected the ESC throttle signal cable directly into the receiver channel 3, temporarily bypassing the pixhawk. I then turned on the transmitter, set the throttle stick to maximum and connected power to the ESC. The ESC beeped once every couple of seconds, indicating it had recorded throttle maximum. I then set the throttle stick to minimum. The ESC beeped with four short beeps to indicate the number of cells of the battery, then one long one to indicate the throttle minimum had been recorded. I checked the throttle range by increasing the throttle stick up to maximum and confirming the motor speed increased to maximum. Accelerometer CalibrationPerform the accelerometer calibration using instructions here. Reference http://ardupilot.org/plane/docs/common-accelerometer-calibration.html Accelerometer Calibration Log
Compass CalibrationCalibrate the compass(es) using instructions here. Reference http://ardupilot.org/plane/docs/common-compass-calibration-in-mission-planner.html Live Calibration was used for compasses #1 and #2. This is the compass calibration screen after calibration showing the offsets for each compass. (Note: Onboard Mag Calibration was not successful, even with relaxed fitness!)
Note that Compass #2 (on the Pixhawk board) is not used because inconsistencies between the 2 compasses prevented arming. Radio CalibrationPerform the radio calibration using instructions here. Reference http://ardupilot.org/plane/docs/common-radio-control-calibration.html Channel 1 = Ailerons, Channel 2 = Elevator, Channels 3 = Throttle, Channel 4 = Rudder, Channel 8 = Flight Mode. This shows the result of the calibration.
Flight Modes ConfigurationSet up the flight modes using instructions here. Reference http://ardupilot.org/plane/docs/common-rc-transmitter-flight-mode-configuration.html I have selected the following flight modes.
Plane FailsafeSet up the failsafe parameters using instructions here. Reference http://ardupilot.org/plane/docs/apms-failsafe-function.html The failsafe parameters are described here. Battery Failsafe
If FS_BATT_MAH is enabled, ensure BATT_CAPACITY is set correctly. Refer here. I have chosen to disable both battery failsafe triggers. Ground Control Station Failsafe
I have chosen to disable the GCS failsafe trigger. Failsafe Action
Note that FS_LONG_ACTN has been changed from the default to RTL (Return To Launch). Throttle Failsafe
The THR_FAILSAFE parameter must be enabled to enable throttle failsafe. Also, the receiver throttle channel must be configured so that when it loses signal, the throttle PWM value is below the THR_FS_VALUE value. Elevon ConfigurationConfigure the elevon control using instructions here. Reference http://ardupilot.org/plane/docs/guide-elevon-plane.html To fly the plane manually before the pixhawk was installed, the elevon mix was done in the transmitter. When the pixhawk was installed and the old style of elevon mixing was used, in the manual modes the elevon channels were passed straight through to the elevon servos. However, to make use of the new style elevon mixing in the pixhawk, the Taranis must deliver one channel for aileron and one for elevator with no mixing. New Style Elevon Mixing (ELEVON_OUTPUT output)Set up the transmitter with no elevon mixing, aileron on channel one and elevator on channel two. (Throttle is channel three.) I set my pixhawk parameters as follows.
In the Taranis transmitter, channel direction was set as follows.
In the pixhawk, the trim parameters are set as follows.
The servo throw parameters were changed as follows.
The mixing parameters in the pixhawk are set as follows.
With all the settings above, the aileron and elevator work correctly in manual mode. Also, in FBWA mode, the elevons work correctly to correct aircraft roll and pitch. Basic Tuning - PID Parameter Set UpThe default tuning parameters are shown here.
The modified settings are as follows
For refining of these settings, see Tuning - Autotune here. ArmingConfigure autopilot arming using instructions here. Reference http://ardupilot.org/plane/docs/arming-throttle.html After power up, all servo values and throttle are kept at minimum values until the safety button is pushed. I have set arming parameters as follows.
All checks are required for the aircraft to be armed. The hardware switch must be pressed for at least three seconds to enable the servos before the motor can be armed. Arming the motor is done by holding the rudder fully right for at least three seconds. Advanced Failsafe ConfigurationSet up the advanced failsafe configuration using instructions here. Reference http://ardupilot.org/plane/docs/advanced-failsafe-configuration.html The advanced failsafe system allows complex series of action when a failsafe event occurs.
The advanced failsafe system is disabled. Sensor TestingSensor testing can be performed using instructions here. Reference http://ardupilot.org/plane/docs/common-sensor-testing.html To display the graph of sensor data, tick the tuning box at the bottom of the page. To display a list of all possible sensor data, double click the left mouse button anywhere on the tuning graph. The following
Magnetic field strength graph of compasses 1 & 2. Moving a magnet close to the remote compass increases magfield to over 2000. Moving a magnet close to the onboard compass increases magfield2 to over 4000.
Battery Capacity SettingIn Mission Planner on the Software Config / Tuning screen, under Parameter List or Parameter Tree, set the battery capacity.
I use a 3000mAh 4S battery. Throttle Control ParametersThese are the default throttle parameters. These values are not changed.
The throttle setting for normal flight TRIM_THROTTLE is set to 55%. This throttle setting is used when there is no airspeed sensor.
Terrain ParametersReference http://ardupilot.org/plane/docs/common-terrain-following.html?highlight=terrain The default terrain parameters are shown here.
TERRAIN_ENABLE is changed to 0 i.e. saving terrain data is disabled. Optional Hardware – Power ModuleBattery Voltage CalibrationBattery voltage measured using a digital multimeter on the battery charge lead pins. Measured value 15.56V. The sensor type was set to ‘Other’ and the 15.56 was entered in the ‘Measured battery voltage’ in the Calibration box. This recalculated the ‘Voltage divider (Calced)’ parameter. The ‘Battery voltage (Calced)’ then showed 15.56V. Current CalibrationUsing a current meter, the motor was run at 9.69 Amps. While it was running, the measured current was entered. This adjusted the ‘Ampers per volt’ to 23.08521 and the ‘Current (Calced)’ then displayed about 9.70A .. close enough allowing for small fluctuations. After voltage and current calibration, the power module parameters are shown here.
Mission Planner Alert on Low BatteryThe ‘MP Alert on low Battery’ checkbox was checked with the following parameters.
Optional Hardware – SiK Telemetry RadioSet up the telemetry radio using instructions here. Reference http://ardupilot.org/plane/docs/common-sik-telemetry-radio.html In Mission Planner, the baud rate was set to 57600 and COM6 was selected. ‘Connect’ was clicked, the link established and the ‘Flight Data’ page showed the current status. Select ’Initial Setup’, then ‘Optional Hardware’, then ‘Sik Radio’. In the top right corner, disconnect the MAVLink, the click ‘Load Settings’. The ‘Sik Radio’ set up screen is shown as follows with the default settings.
For advanced Configuration, refer here Optional Hardware – Airspeed SensorReference http://ardupilot.org/plane/docs/airspeed.html In Mission Planner, tick the ‘Use Airspeed’ box.
The default airspeed parameters are shown here.
These default values are not changed. Airspeed Sensor TuningParameter ARSPD_AUTOCAL is set to 1 temporarily during the first flight to calibrate the airspeed sensor. The default value of ARSPD_OFFSET is 2058.929 and the default value of ARSPD_RATIO is 1.9936. A couple of ten minute flights in manual mode were then made. After auto calibration, the new value of ARSPD_OFFSET became 2083.669 and the new value of ARSPD_RATIO became 2.100493. The value of ARSPD_AUTOCAL was then set back to 0. Optional Hardware – Stabilised Camera Gimbal – Servo ControlledConfigure the servo controlled gimbal using instructions here. Reference http://ardupilot.org/plane/docs/common-camera-gimbal.html
The gimbal was also made from aluminium and mounted on the platform.
On Mission Planner, the gimbal was configured as shown here.
Important Gimbal Design Notes
To prevent unwanted vibration and gear wear, follow these guidelines.
These features minimise secondary vibrations arising in the assembly. Field Of ViewIf
the camera is horizontal, the horizon is across the middle of the picture and
the top half is sky. I set the tilt angle to about 24°
so that the camera’s field of view had the horizon just below the top of the
frame and the rest of the frame is filled with the ground in front of the
aircraft.
A video showing the gimbal operation is here : http://www.youtube.com/watch?feature=player_detailpage&v=0HGa-9Ns_Nw Tuning – AutotuneReference http://ardupilot.org/plane/docs/automatic-tuning-with-autotune.html?highlight=autotune After the first flight, the PID parameters can be refined by performing an autotune. Basically the procedure involves selecting autotune mode and flying while making rapid roll and pitch changes separately. At least 20 rapid changes are needed for roll and for pitch.
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