GTOP:Gradient-Based Trajectory Optimizer
(This repo is mainly developed and maintained by Boyu Zhou, please contace him if necessary)
1.Introduction
Gradient-Based Online Safe Trajectory Generation is trajectory optimization framework, for generating a safe, smooth and dynamically feasible trajectory based on the piecewise line segment initial path. The planning problem is formulating as minimizing the penalty of collision cost, smoothness and dynamical feasibility.
Authors:Fei Gao,Boyu Zhou,and Shaojie Shen from the HUKST Aerial Robotics Group.
Disclaimer
This is research code, any fitness for a particular purpose is disclaimed.
Related Paper
- Gradient-Based Online Safe Trajectory Generation for Quadrotor Flight in Complex Environments, Fei Gao, Yi Lin and Shaojie Shen
Video of this paper can be found here.
If you use this generator for your academic research, please cite our related paper.
@inproceedings{Fei2017IROS,
Address = {Vancouver, Canada},
Author = {F. Gao and W.Wu and Y. Lin and S. Shen},
Booktitle = {Gradient-Based Online Safe Trajectory Generation
for Quadrotor Flight in Complex Environments},
Title = {Proc. of the {IEEE/RSJ} Intl. Conf. on Intell. Robots and Syst.},
Month = Sept.,
Year = {2017}}
}
2.Prerequisities
Our testing environment: Ubuntu 14.04, ROS Indigo.
We use NLopt as optimization solver. Installation is straight forward. Just download, extract and compile:
mkdir build
cd build
cmake ..
make
Finally you should install it.
sudo make install
Detailed information can be found here.
Note:The default installation prefix of NLopt is /usr/local
3.Build on ROS
Clone the repository to your catkin workspace and catkin_make. For example:
cd ~/catkin_ws/src
git clone https://github.com/HKUST-Aerial-Robotics/grad_traj_optimization.git
cd ../
catkin_make
source ~/catkin_ws/devel/setup.bash
4.Random Map and Waypoints Example
Open two terminals and run:
roslaunch grad_traj_optimization traj_rviz.launch
roslaunch grad_traj_optimization random.launch
After running and open rviz with traj.rviz file, you should find a randomly built collision map with some waypoints going through it. Then a smooth and collision free trajectory is generated.
5.Random Map and Clicked Waypoints Example
Similarly, run:
roslaunch grad_traj_optimization traj_rviz.launch
roslaunch grad_traj_optimization click.launch
Likewise, a random collision map is built but with fewer obstacles. Then you can click in rviz using 2D Nav Goal to add some waypoints. The Z coordinate of each waypoint is set to 2.0. The default waypoint number is 7 and you can change it in click.launch. Trajectory is generated as long as enough waypoints are added.
Note:Trajectory with too many segments or with sharp corner is difficult to optimized and is tend to fail.
6.Text Input Example
If you want to set the collision map and waypoints as much as you like, run
roslaunch grad_traj_optimization traj_rviz.launch
roslaunch grad_traj_optimization text_input.launch
Instead of randomly generated ,the collision map and waypoints in this example is specified in text_input.launch.Just change it to what you want.
7.Acknowledgements
We use NLopt for non-linear optimization and sdf_tools for building signed distance field.
8.Licence
The source code is released under GPLv3 license.