Control of Outdoor Robots

Goran Huskić

Fast and safe autonomous outdoor navigation of mobile robots is an open and challenging problem, with various possible applications, such as agriculture, search and rescue, exploration or inspection. Furthermore, human-robot cooperation (such as person following) in rough terrain conditions, dynamic environments, and at higher speeds makes the task even more challenging.


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



Person following


We propose a full navigation system for outdoor person following at higher speeds. Our system includes path planning, path following control and obstacle avoidance. It allows the robot to follow a jogger in various outdoor scenarios, fully autonomously.


Person Following Video


Video 1: Demonstration of our new navigation system


Path following


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


Path Following Video with Robotnik Summit XL


Video 2: Demonstration of our path following controller on a Robotnik Summit XL robot

As a product of collaboration with LAAS-CNRS in Toulouse, France, the proposed controller is evaluated on a Segway RMP 440 robot as well. A video demonstrating these experiments is shown below.

Path Following Video with Segway RMP 440


Video 3: Demonstration of our path following controller on a Segway RMP 440 robot

Evaluation


As seen in the videos, the controller is evaluated on different and challenging terrain types. The experiments were conducted at higher speeds: with Robotnik Summit XL at speeds up to 2.5 m/s, and with Segway RMP 440 at speeds up to 6.16 m/s. The proposed controller outperformes two other state-of-the-art-algorithms in all cases. Details can be found in [2]. Example results can be seen in Fig. 2 and Fig.3.



Fig.2:Results from one of the experiments on a grassy flat terrain with Robotnik Summit XL: 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



Fig.3:Results from one of the experiments on an uneven grassy terrain with Segway RMP 440: blue - desired path, red - actual path;
path length: 400.14 m, mean error = 12 cm, max error = 44.19 cm, mean speed = 3.12 m/s, max speed = 3.54 m/s

 

 

References

[1] Goran Huskić, Sebastian Buck, Luis Azareel Ibargüen González, and Andreas Zell. Outdoor person following at higher speeds using a skid-steered mobile robot. In Intelligent Robots and Systems (IROS), 2017 IEEE/RSJ International Conference on, Vancouver, Canada, September 2017. (accepted for publication). [ details ]
[2] 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. [ details ]
[3] Goran Huskić, Sebastian Buck, and Andreas Zell. A simple and efficient path following algorithm for wheeled mobile robots. In Intelligent Autonomous Systems (IAS), The 14th International Conference on, Shanghai, CN, July 2016. [ DOI | details ]
[4] Sebastian Buck, Richard Hanten, Goran Huskić, Gerald Rauscher, Alina Kloss, Jan Leininger, Eugen Ruff, Felix Widmaier, and Andreas Zell. Conclusions from an object-delivery robotic competition: Sick robot day 2014. In Advanced Robotics (ICAR), The 17th International Conference on, pages 137-143, Istanbul, TR, July 2015. [ DOI | details | link | pdf ]
[5] Ran Liu, Goran Huskić, and Andreas Zell. On Tracking Dynamic Objects with Long Range Passive UHF RFID Using a Mobile Robot. International Journal of Distributed Sensor Networks (IJDSN), Article ID 781380, 2015. [ link ]
[6] Ran Liu, Goran Huskić, and Andreas Zell. Dynamic Objects Tracking with a Mobile Robot using Passive UHF RFID Tags. In IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2014), Chicago, Illinois, USA, 2014. [ details ]

 




Contact

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