airsim_ros packages

AirSim ROS packages: modified ros wrapper for airsim, and some vslam related tools. (Mainly focused on Car SimMode).

A demo City simulation environment in unreal is provided.

Package overview

• airsim_ros_pkgs: Modified ros wrapper for airsim
• airsim_car_teleop: A keyboard teleop ros node to control the simulating Car in airsim
• settings: Vslam simulation tests setting files
• simu_tools: Simulation related tools for handling the trajectory ground truth & dataset postprocessing

Features

• Campared with the original ROS node, the stereo images timestamps sync problem is solved(ref). Now the timestamp difference between a left and a right image is at max 0.003 second (ubuntu 16.04, 32G, ros-kinetic, UE 4.24, no GPU).

### A ROS node for the Car SimMode, according to the original repo of microsoft/AirSim:
roslaunch airsim_ros_pkgs airsim_car_with_joy_control.launch

### A self-written ROS node for the Car SimMode (No longer maintained, since microsoft/AirSim supports Car ROS node now)
roslaunch airsim_ros_pkgs airsim_car_node.launch

• If you do not have a joy control hardware, here is a keyboard control node for the Car simulated with the ROS node above. Usage:

roslaunch airsim_car_teleop airsim_car_teleop_joy.launch

• Simulation tools are provided to convert the car trajectory ground truth rostopic to a txt file (TUM), for evaluation postprocessing purpose. If there are any unexpected empty images in the dataset (with the phenomenon: an opencv Exception "Image is wrongly formed: height * step != size or 0 * 0 != 1" raised), there is a python script to remove them.

### Either use the pose recorder node to record the ground truth during simulation: 
roslaunch simu_tools car_pose_recorder output_filename rostopic_name

### Or use the python script /simu_tools/scripts/groundtruth_extractor.py to extract the ground truth from a rosbag. 
./groundtruth_extractor.py

### To move the empty images:
./images_remove.py

• Along with the releases, an editable demo City simulation environment is provided to test the ROS wrapper (for linux only). The AirSim plugin in this environment is a modified version from this repo: GimpelZhang/AirSim, which is trying to solve the simulation speed problem in the Car SimMode ClockSpeed setting.

More applications in vslam:

Known bugs:

1. The weather option doesn't work. Described in the [issue](https://github.com/microsoft/AirSim/issues/2957)

2. Empty images occasionally occur in output image rostopics. Temporarily the solution is images_remove.py