Configuring APM for Parrot C.H.U.C.K

1. Installing a Ground Control Station

 

To set the Parrot C.H.U.C.K's parameters, you must install a GCS (Ground Control Station).

We selected APM Planner 2.0. Download it from:

http://firmware.eu.ardupilot.org/Tools/APMPlanner/

 

APM Planner version 2.0.24 is available for Windows, Mac OS X and Linux.

Documentation (in English) is available from the ardupilot website:

http://ardupilot.org/planner2/

 

Note: There are other GCSs of the same type, such as Mission Planner and QgroundControl, that work in the same way.

 

2. Installing the APM software on Parrot C.H.U.C.K

 

  1. Install FileZilla.
  2. Go to http://firmware.eu.ardupilot.org/Plane/stable/disco/.
  3. Download the latest stable version of APM Plane for Parrot C.H.U.C.K: arduplane.
  4. Rename the file apm-plane-disco (with no extension).
  5. Switch the Parrot C.H.U.C.K. on.
  6. Wait approximately 15 seconds, until the blue LED flashes at a frequency of about 1 Hz.
  7. Connect to the Parrot C.H.U.C.K. Disco-XXXXXX access point.
  8. Run FileZilla.
  9. Go to Edit, then open the Preferences or Settings menu. 
    The Preferences or Settings window opens.
  10. In Transfers select File Types.
  11. Uncheck the Treat files without extension as ASCII file checkbox, then click OK.

A1.jpgFigure 1: Changing the type of file to be transferred

  • Enter the address 192.168.42.1 in the Host field, then click Quickconnect.
  • Create a folder in internal_000 and name it APM. 
  • Copy file apm-plane-disco into the APM folder.

A2.jpgFigure 2: Copying the file apm-plane-disco to Parrot C.H.U.C.K

  • Press the Parrot C.H.U.C.K’s on/off button three times to launch APM. 
    The LED flashes red and blue then slowly flashes yellow.  
     

 

3. Configuring the remote control (Futaba T10J)

 

By default, controls for roll, pitch, motor and yaw are sent over channels 1, 2, 3 and 4 respectively. These channels cannot be changed with the Futaba T8J and T10J remote controls.

 

For consistency, we decided to add a three-way switch to channel 5. This switch will be our gear to change flight mode.

 

The radio is therefore configured as follows:

 

Channel

Operation

1

Aileron

2

Elevator

3

Throttle

4

Rudder

5

Gear

 

 

4. Configuring Parrot C.H.U.C.K

 

The Parrot C.H.U.C.K has 7 outputs (6 x 3-pin servo connectors + motor I2C ESC output).

 

The motor I2C ESC can be used for a brushless motor and for the Parrot Disco.

 

The Parrot C.H.U.C.K output channels are configured as follows:

 

Channel output

Physical output

1

Pin 1

2

Pin 6

3

Sortie  I2C ESC moteur

4

Pin 2

5

Pin 5

6

Pin 3

7

Pin 4

 

 

For example, Parrot Disco has two servomotors as well as a brushless motor.

A3.jpg

Figure 3: Parrot Disco

  

The left servomotor is connected to pin 1, the right servomotor to pin 6, and the brushless motor to the I2C ESC output.

 

Once this is done, you can control the Parrot Disco by plugging in a receiver, since the outputs now map to channels 1, 2 and 3, i.e. the aileron, elevator and throttle, sent over channels 1, 2 and 3 by the remote control. Parrot C.H.U.C.K performs mixing between output channels 1 and 2 to both servomotors.

 

 

 

 4.1  3S Configuration using the Parrot C.H.U.C.K output

 

Our Acrobat plane has four servomotors:

  • one for each aileron
  • one for the elevator
  • one for the rudder 

Use a Y-connector to connect the two aileron servomotors to pin 1.

Connect the elevator servomotor to pin 6.

Connect the rudder servomotor to pin 2, which maps to channel 4.

 

Our configuration looks like the table below:

 

Radio channel output

C.H.U.C.K channel output

C.H.U.C.K physical output

Function

1

1

Pin 1

aileron

2

2

Pin 6

elevator

3

3

I2C ESC motor

throttle

4

4

Pin 2

rudder

5

NA

NA

gear

  

Now, we just need to connect the Futaba receiver to the Parrot C.H.U.C.K to complete the installation shown below (with a single servomotor for the aileron):

  

A4.jpgFigure 4: Configuration using the Parrot C.H.U.C.K. motor output

 

However, the Acrobat plane’s manual recommends using a 4S battery, so we decided to use the ESC delivered with the plane to take advantage of the motor's maximum power.

We chose pin 5, mapping to output channel 5. We’ll be using a 2800mAh 4S battery to supply both the motor and CHUCK, thanks to its connector.  

4.2 4S Configuration using the ESC delivered with the plane

 

A5.jpg

Figure 5: 4S Configuration using the ESC

 

Our 4S configuration is :

 

Radio channel output

C.H.U.C.K channel output

C.H.U.C.K physical output

Function

1

1

Pin 1

aileron

2

2

Pin 6

elevator

3

5

Pin 5

throttle

4

4

Pin 2

rudder

5

NA*

NA*

gear

 

Please note: Channel 5 is only used for the gear. Commands from this channel are never sent to a servomotor.

 

We’ll apply this configuration to our plane by fastening the Parrot C.H.U.C.K under the plane, at its centre of gravity, using hook-and-loop fasteners.

 

A6.jpg

Figure 6: Incorporating Parrot C.H.U.C.K in the plane

 

The Pitot sensor included with Parrot C.H.U.C.K could have been disrupted because of the plane’s propeller and fuselage. So we recovered a tube with the same inner diameter to move the Pitot to one of the plane’s wings:

 

 

A7.jpg

Figure 7: Moving the Pitot to the plane’s wing

 

A8.jpg

Figure 8: Mounting Parrot C.H.U.C.K onto the Acrobat plane

 

A9.jpg

Figure 9: Mounting Parrot C.H.U.C.K onto the Acrobat plane

 

5. Establish the connection between the control sation and Parrot C.H.U.C.K

 

  1. Connect the SBUS receiver to the Parrot C.H.U.C.K (see figures 4 and 5)
  2. Switch the Parrot C.H.U.C.K. on, pair the receiver with the radio, then press the on/off button three times to run APM.
  3. Connect to the Parrot C.H.U.C.K access point (Disco-XXXXXX)
  4. Run APM Planner (or another control station).
  5. In the Communication tab, select UDP with port number 14550, then click Connect.  

The connection is made. To the right of the current flight mode, an icon shows the connection status: green when connected, red when disconnected.

 

 

A10.jpg

 

6. Plane settings 

Caution : we strongly recommend removing the propeller before beginning.

 

Parrot C.H.U.C.K. has an on-board list of settings that you can change to match our plane’s configuration.

 

We recommend setting flight mode to “manual” in the config/tuning tab, so you can how the servomotors work in response to the control commands sent.

By default, like the radio, APM sends the aileron over channel 1, the elevator over channel 2, the throttle over channel 3 and the rudder over channel 4.

 

By moving the aileron and elevator joysticks on our radio, you can see mixing between pitch and the aileron, which must be disabled.

 

To change the settings, activate advanced mode and open the full list of settings in Config/Tuning.

 

To disable mixing, set the ELEVON_OUTPUT setting to 0.

 

A11.jpg

 

Since we connected the ESC to pin 5, we have to change the setting that sends motor commands over channel 3 (i.e. the Parrot C.H.U.C.K motor output) by default, and send the command over channel 5.

 

Set the RC5_FUNCTION setting to 70. APM interprets this number as meaning that the servomotor on channel 5 is an auxiliary motor:

http://ardupilot.org/copter/docs/common-CHUCK-overview.html

 

We also decided to change the min and max airspeeds for FBW flight modes and set them to 14 m/s and 24m/s respectively.

 

ASPD_FBW_MAX = 24

ASPD_FBW_MIN = 14 

 

7. Calibrating the radio

 

Caution : remove the propeller before beginning.

 

Once the servomotors’ mechanical trims with the radio are completed, you need to calibrate the remote control in APM. This calibration is done in Initial Setup > Radio Calibration.

 

By moving the control joysticks and the gear switch, APM will get the min, neutral (trim) and max PWM values for each input channel, and use them for the corresponding output channels.

 

APM will use the min, neutral and max PWM values for input channel 5 (the gear) and apply them to output channel 5 (the ESC), so you will have to manually change the settings for channel 5 by applying the values for output channel 3. Replace the values RC5_MIN, RC5_TRIM, RC5_MAX by those from RC3_MIN, RC3_TRIM, RC3_MAX.

 

For more information, see the detailed procedure on the ardupilot website:

http://ardupilot.org/copter/docs/common-radio-control-calibration.html

  

8. Settings for the flight modes (Futaba T10J)

 

In the APM Planner Initial Setup tab, open the Flight modes menu. You can parametrize the six flight modes from this menu.

You can switch between the available flight modes by actioning the remote control switch for the gear.

 

A12.jpg

Figure 12: Flights modes in APM

 

To switch to a flight mode, use the various positions of our gear. APM controls the change of flight mode according to the PWM sent by the remote control. Each flight mode maps to a given PWM range (see image 1).

You can see the PWM sent on each radio channel in the Radio calibration menu. So, by moving the position of the gear's switch, you can see the various PWMs available and change flight mode. For example, with our Futaba T10J, the three positions of the switch (up, middle, down) respectively send by default PWMs of 964, 1514 and 2064, which map to flight modes 1, 4 and 6.

 

To gain access to all the flight modes via the remote control, activate a “prog mix” with a 2-way switch that will alter the PWMs sent to the receiver.

 

First, you need to change the gear’s end points to reduce the total PWM range.

Instead of the default 100% for min and max, set the end points to 47%.

 A13.jpg

Figure 13: End points

 

In the Radio calibration menu, you can see that the min and max PWMs sent over channel 5 have been changed: 1255 for min and 1773 for max. However, the PWM for the neutral position has not changed. It is still set to 1514.

 

With the minimum PWM now set to 1232, we no longer have access to APM flight mode 1. From now on, by changing the gear positions, the available flight modes are modes 2, 4 and 6.


To access flight modes 1, 3 and 5, we’ll activate a “prog mix” with a 2-way switch as master and our gear as slave. The “prog mix” is only active when the switch is in the high position with a rate of+20%. With this rate, you can change the PWMs sent over channel 5 and get PWMs of 1204, 1462 and 1721 for the three positions of our gear.

 

A14.jpg

Figure 14: Prog mix

 

We now have our six flight modes:

Switches positions

PWM values

Flight mode

Gear UP / Switch UP

1204

1

Gear UP / Switch DOWN

1255

2

Gear MID / Switch UP

1462

3

Gear MID / Switch DOWN

1514

4

Gear DOWN / Switch UP

1721

5

Gear DOWN / Switch DOWN

1773

6

 

Have a good flight !

 

ARDUPILOT

The ArduPilot software on-board the Parrot C.H.U.C.K. is free software, distributed by Parrot Drones SAS under the GNU GPL v.3 licence.

For more information on the terms and conditions of this licence, please see https://www.gnu.org/licenses/gpl-3.0.html. Unofficial translations of this licence are also available at https://www.gnu.org/licenses/translations.en.html.

PARROT DRONES SAS DOES NOT WARRANT AND CANNOT BE HELD LIABLE FOR THE PRE-LOADED VERSION OF THE ARDUPILOT SOFTWARE OR FOR ITS USE WITH PARROT C.H.U.C.K.

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