Special Issue on Real World Robot Challenge in Tsukuba – Autonomous Technology for Coexistence with Human Beings –

In this fourth of the “Special Issues on Real World Robot Challenge in Tsukuba,” we feature the control technology of autonomous robots. There is no guarantee that it will operate perfectly in a real-world environment even with the method already revealed. Participating robots in Tsukuba Challenge are required to carry out the assigned tasks under the prevailing weather conditions on the day of the events. Robots avoid oncoming pedestrians and obstacles in their path. In order to share the novel technology of the autonomous control method, this special issue presents a summary of the results of robots that participated in past Tsukuba Challenges. It is only thanks to the ongoing efforts of the organizers of Tsukuba Challenge and the enthusiasm on the part of the participants that we are able to present an issue such as this, and we are truly thankful to them. We also wish to thank the authors who submitted papers and articles for this issue, as well as our reviewers.