The Erle Copter was assembled according to the Erle Copter: Assembly Instructions. Additionally to the described tools, fitting screwdrivers, a nut wrench, four AA batteries for the RC Controller, a scissor, a micro-USB cable, and a knife were used, contrarily the super glow was not used. The 3D printed battery holder was cut with the knife for a better fit. There were no instructions for the Anti-Vibration System. Currently, the vibration system has to rebuild after every hard landing. The micro-USB cable is necessary since the UART port is blocked by the GPS and only one micro-USB cable is provided, which is in use for the laptop-to-telemetry connection.
For this part, several guides were used such as First Flight, Connect via SSH, and Connect APM. The OS image and arducopter/APM was preinstalled on the microSD. The Erle Brain 3 has an HDMI connection, which was used for direct access. The drone received internet access via ethernet from a windows laptop, which shared his Wifi access. Direct access to the university's internet was not possible via ethernet or wifi. The command to update (curl) the keys on the drone gives back an error "gpg: keyserver timed out", maybe because of the proxy settings of the used public network. Not all packages can be updated since the package apm-copter-erlebrain cannot be found. SSH access to the drone via ethernet is possible, the IP address of the drone change with every reboot. Calibration was done with QGroundControl via telemetry on a Linux laptop, the program does not show the GPS information. Listening to the UART connection shows that when the GPS is connected, information is sent and no information is received if not. On a windows laptop, QGroundControl shows some information, but an error message was displayed that the vehicle did not respond to the parameter request. The telemetry connection frequently dis- and reconnects. Once the APMPlaner2 showed some information on the windows laptop but this has not been reproduced yet.
To receive the image of the erle brain operating system, it is required to send an email to Erle Robotics. After making a backup of the old OS, we flashed Erle-Brain-3-frambuesa-update-04-07-2017.img on the microSD. We installed apm-copter-3.5-stable-erlebrain using apt (apm-copter-erlebrain package was not available even after the successful key update). For the key update, we had to use a mobile connection since the public network available to us seems to have interfering proxy settings. We calibrated the RC Controller with the Drone and heard the music sound. We connected with windows and Linux laptops to the WiFi network provided by the copter. Windows does not receive an IP address in the drone's WiFi automatically, therefore the IP has to be manually set to 10.0.0.2. The windows firewall was also disabled. We loaded .params according to this link. We used QGroundControl to calibrate the compass and accelerometer. We added /bin/sleep 10 before while loop in ./apm.sh, this might not be necessary. Connection via WiFi makes interaction with APM and QGroundControl possible. Telemetry requires 57600 baud rate. To get GPS Fix the drone needs to be outdoors. It might take five or more minutes to get several satellites, seven satellites and a GPS speed of less than 1.0 are needed by QGroundControl, otherwise, it will not allow take off.
Install QGroundControl on an android phone. Connect to the drone via WiFi or telemetry radio. WiFi has a higher bandwidth, so the initialization/loading of the parameters is faster. WiFi should have about 200m range and telemetry radio more than 300m. Check if the QGroundControl app has the UDP link configured.
How to fix -lwrap error? /usr/bin/x86_64-linux-gnu-ld: cannot find -lwrap #52
How to connect Icarous and MAVProxy #53
Installing Icarous differs a bit depending on the operating system and the CPU architecture. It might be worth it to write the export commands into a script. We recommend the export commands because the recommend changes to the ~/.bashrc script according to the official installation guide didn't work for us. Of course the used commands might need to be adjusted to the current version.
We didn't figure out how to set a compilation flag for ARM/how to make the cmake run the ELSE() condition on line 45 of the cmakelists.txt, therefore we just commented lines 42-45 and 47 out.
sudo su
apt-get install git
apt-get install cmake
apt-get install oracle-java8-jdk
git clone https://github.com/nasa/icarous.git
sudo git submodule update --init --recursive
cd Icarous
nano cmakelists.txt
Lines 42-47 change to ARM
export JAVA_HOME="/usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt"
export PLEXIL_HOME="/home/erle/icarous/Modules/Plexil"
export OSAL_HOME="/home/erle/icarous/cFS/cFE/osal"
ln -sf /lib/i386-linux-gnu/libwrap.so.0 /usr/lib/x86_64-linux-gnu/libwrap.so
cd build && cmake ..
make cpu1-install
cd cFS/bin/cpu1
./core-cpu1
sudo su
apt-get install git
apt-get install cmake
apt-get install oracle-java8-jdk
apt-get install tcpd:i386
apt-get install g++-multilib
apt-get install gcc-multilib
apt-get install zlib1g-dev
git clone https://github.com/ArduPilot/MAVProxy.git
git clone https://github.com/nasa/icarous.git
cd Icarous
sudo git submodule update --init --recursive
export JAVA_HOME="/usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt"
export PLEXIL_HOME="/home/erle/icarous/Modules/Plexil"
export OSAL_HOME="/home/erle/icarous/cFS/cFE/osal"
ln -sf /lib/i386-linux-gnu/libwrap.so.0 /usr/lib/x86_64-linux-gnu/libwrap.so
cd build && cmake ..
make cpu1-install
cd ../Python/CustomModules
bash SetupMavProxy.sh /home/username
/home/username/MAVProxy/MAVProxy/mavproxy.py --master=/dev/ttyUSB0,56700 --map --console --load-module geofence,traffic,icparams
