Indoor-Flight

This repo provides documentation/tutorials of setup for indoor flight with OptiTrack motion capture system in offboard mode of pixhawk.

ODROID XU4 Setup

Static ip for ODROID XU4

It is recommended to use static ip address if you plan to use ODROID via a WiFi network. Follow these steps for setting the static ip:

Check the WiFi card number with the following command

ifconfig -a

To set a static IP address open /etc/network/interfaces file for editing by the following command

sudo nano /etc/network/interfaces

Add or edit following lines to the file, and make sure it matches your WiFi network. Added lines should look similar to this.

auto wlan0 # The following will auto-start connection after boot
allow-hotplug wlan0 # wlan0 WiFi card number
iface wlan0 inet static
address 192.168.0.xxx # Choose a static IP, usually you change the last number only for different devices
netmask 255.255.255.0
broadcast 192.168.0.255
gateway 192.168.0.1 # Your router IP address
dns-nameservers 8.8.8.8
wpa-ssid "DroneLab" # WiFi name (case sensitive)
wpa-psk "12345dronelab" # WiFi password

Install ROS

To install ROS noetic on ODROID or ARM-based single-board-computer, follow these instructions available on the ROS website. Make sure to install the ROS-Base: (Bare Bones) and not the full desktop version.

So when you reach the step to install ROS with apt get don't execute sudo apt install ros-noetic-desktop-full, instead use sudo apt install ros-noetic-ros-base.

Install MAVROS

This package is used to interface MAVLink-based autopilots to ROS.

We will simply follow the well documented wiki on MAVROS github page. For the source installation while building the packages with catkin build make sure to use the argument -j1. So you execute catkin build -j1

Check if mavros works fine, e.g. roslaunch mavros px4.launch

Install vrpn_client_ros ROS package

In order to recieve data in ROS from an OptiTrack system running the Motive software, VRPN streaming engine with the vrpn-client-ros ROS package can be used.

The following describes the ways to setup and install the package

cd ~/catkin_ws/src

git clone -b kinetic-devel https://github.com/ros-drivers/vrpn_client_ros

rosdep install --from-paths src/vrpn_client_ros --ignore-src

cd ~/catkin_ws

catkin build

Motion Capture System Setup : OptiTrack

Basic setup

To create a rigid body for streaming, select the markers of the object (at least three) and right-click in Motive and select Rigid Body -> Create From Selected Markers. Make sure the Name for the object to be tracked does not have any whitespaces.

Then you can see a new rigid body in the Assests pane. Note that only those objects would be streamed where the checkbox is checked in the Assests pane.

Activate the checkbox for Broadcast Frame Data from the Streaming pane.

Feeding MOCAP data into Pixhawk

You need to set your flight controller firmware PX4, to accept mocap data. PX4 has two state estimators, EKF2(default) an extended Kalman filter, and LPE.

EKF2 parameters update

• SYS_COMPANION = Companion Link (921600 baud, 8N1)
• MAV_1_CONFIG = TELEM 2
• MAV_1_MODE = Onboard
• SER_TEL2_BAUD = 921600
• EKF2_AID_MASK = 24 Set EKF2_AID_MASK to use vision position fusion and vision yaw fusion.
• EKF2_HGT_MODE = Vision
• EKF2_ASP_DELAY = 0.0 ms
• EKF2_EV_DELAY = 50.0 ms
• EKF2_OF_DELAY = 0.0 ms

Getting pose data into ROS

Run the vrpn_client_node as follows

roslaunch vrpn_client_ros sample.launch server:=192.168.0.101

If you named the rigidbody as robot1, you will get the MoCap data on the topic like /vrpn_client_node/robot1/pose.

Relaying/remapping the pose data

Run the MAVROS node

roslaunch mavros px4.launch fcu_url:=/dev/ttyUSB0:230400 gcs_url:=udp://@192.168.1.54:14550

MAVROS provides a plugin to relay pose data published on /mavros/vision_pose/pose to PX4. Assuming that MAVROS is running, you just need to remap the pose topic that you get from MoCap /vrpn_client_node/<rigid_body_name>/pose directly to /mavros/vision_pose/pose.

rosrun topic_tools relay /vrpn_client_node/droneLOP/pose /mavros/vision_pose/pose

Running the node for offboard mode control

rosrun offboard_py offb_node.py

Results

Position Setpoints

                             x = $0$, y = $0$, z = $1.5$

Square Trajectory

Troubleshooting

Errors     << mavros:make /home/odroid/catkin_ws/logs/mavros/build.make.002.log
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [CMakeFiles/mavros.dir/build.make:154: CMakeFiles/mavros.dir/src/lib/uas_data.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....
c++: fatal error: Killed signal terminated program cc1plus
compilation terminated.
make[2]: *** [CMakeFiles/mavros.dir/build.make:128: CMakeFiles/mavros.dir/src/lib/mavros.cpp.o] Error 1
In file included from /usr/include/c++/9/unordered_map:47,
                 from /home/odroid/catkin_ws/src/mavros/mavros/src/lib/enum_sensor_orientation.cpp:17:
/usr/include/c++/9/bits/unordered_map.h: In constructor ‘std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(std::initializer_list<typename std::_Hashtable<_Key, std::pair<const _Key, _Tp>, _Alloc, std::__detail::_Select1st, _Pred, _Hash, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<std::__not_<std::__and_<std::__is_fast_hash<_Hash>, std::__is_nothrow_invocable<const _Hash&, const _Key&> > >::value, false, true> >::value_type>, std::unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type, const hasher&, const key_equal&, const allocator_type&) [with _Key = unsigned char; _Tp = const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> >; _Hash = std::hash<unsigned char>; _Pred = std::equal_to<unsigned char>; _Alloc = std::allocator<std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > > >]’:
/usr/include/c++/9/bits/unordered_map.h:227:7: note: parameter passing for argument of type ‘std::initializer_list<std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > > >’ changed in GCC 7.1
  227 |       unordered_map(initializer_list<value_type> __l,
      |       ^~~~~~~~~~~~~
/usr/include/c++/9/bits/unordered_map.h:232:40: note: parameter passing for argument of type ‘std::initializer_list<std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > > >’ changed in GCC 7.1
  232 |       : _M_h(__l, __n, __hf, __eql, __a)
      |                                        ^
In file included from /usr/include/c++/9/unordered_map:46,
                 from /home/odroid/catkin_ws/src/mavros/mavros/src/lib/enum_sensor_orientation.cpp:17:
/usr/include/c++/9/bits/hashtable.h: In constructor ‘std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::_Hashtable(std::initializer_list<_Value>, std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash, _RehashPolicy, _Traits>::size_type, const _H1&, const key_equal&, const allocator_type&) [with _Key = unsigned char; _Value = std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > >; _Alloc = std::allocator<std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > > >; _ExtractKey = std::__detail::_Select1st; _Equal = std::equal_to<unsigned char>; _H1 = std::hash<unsigned char>; _H2 = std::__detail::_Mod_range_hashing; _Hash = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<false, false, true>]’:
/usr/include/c++/9/bits/hashtable.h:492:7: note: parameter passing for argument of type ‘std::initializer_list<std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > > >’ changed in GCC 7.1
  492 |       _Hashtable(initializer_list<value_type> __l,
      |       ^~~~~~~~~~
/home/odroid/catkin_ws/src/mavros/mavros/src/lib/enum_sensor_orientation.cpp: In function ‘void __static_initialization_and_destruction_0(int, int)’:
/home/odroid/catkin_ws/src/mavros/mavros/src/lib/enum_sensor_orientation.cpp:120:2: note: parameter passing for argument of type ‘std::initializer_list<std::pair<const unsigned char, const std::pair<const std::__cxx11::basic_string<char>, const Eigen::Quaternion<double> > > >’ changed in GCC 7.1
  120 | }};
      |  ^
make[1]: *** [CMakeFiles/Makefile2:1185: CMakeFiles/mavros.dir/all] Error 2
make: *** [Makefile:141: all] Error 2
cd /home/odroid/catkin_ws/build/mavros; catkin build --get-env mavros | catkin env -si  /usr/bin/make --jobserver-auth=3,4; cd -

...............................................................................
Failed     << mavros:make                [ Exited with code 2 ]                
Failed    <<< mavros                     [ 3 minutes and 32.1 seconds ]        
[build] Summary: 3 of 4 packages succeeded.                                    
[build]   Ignored:   2 packages were skipped or are skiplisted.                
[build]   Warnings:  None.                                                     
[build]   Abandoned: None.                                                     
[build]   Failed:    1 packages failed.                                        
[build] Runtime: 4 minutes and 30.0 seconds total.

Solution : Use catkin build -j1, which will run only one instance of the g++, that is slower, but you'll fit in less RAM. You can refer this for resolving this error.

• [ERROR]:FCU:Fail:CPU load too high

Solution : Change the value of the EKF2 parameter IMU_GYRO_RATE to 400