Control of Outdoor Robots

Goran Huskić

This research deals with the motion control task of wheeled mobile robots in outdoor scenarios. It includes path planning, path and person following, and obstacle avoidance. The two main difficulties are:


  1. high speed, and
  2. challenging terrain.

For the purpose of this research, we use two skid-steered mobile robots Summit XL from the company Robotnik. Controlling a skid-steered vehicle is additionally challenging, since its motion cannot be described with pure rolling, without slipping and sliding.



summit_front summit_back

Fig.1 One of our Summit XL robots, front and back view



Path following


Path following focuses on minimizing the distance and orientation error between the robot and a geometric reference path. Our recent results allow accurate path following at higher speeds, on different terrain types, both indoors and outdoors. A demonstration of our newly proposed controller can be seen in the video below.


Path Following Video


Video 1: Demonstration of our new path following controller

Experimental Results


As seen in the video, the controller is evaluated on three challenging terrain types: grass, vinyl and macadam. The experiments were conducted at higher speeds (up to 2.5 m/s), and the controller outperformed two other state-of-the-art-algorithms. Details can be found in our recent ICRA 2017 publication. Example results on grass can be seen in Fig. 2.



Fig.2:Results from one of the experiments on grass: red - desired path, blue - actual path;
path length: 159.83 m, mean error = 6.9 cm, max error = 22.36 cm, mean speed = 2.15 m/s, max speed = 2.54 m/s

 

 

References

[1] Goran Huskić, Sebastian Buck, and Andreas Zell. Path following control of skid-steered wheeled mobile robots at higher speeds on different terrain types. In IEEE International Conference on Robotics and Automation (ICRA), Singapore, 2017. (accepted for publication). [ details ]

 




Contact

Goran Huskić, Tel.: (07071) 29-77176, goran.huskic at uni-tuebingen.de