start-ver=1.4 cd-journal=joma no-vol=27 cd-vols= no-issue=15 article-no= start-page=1147 end-page=1160 dt-received= dt-revised= dt-accepted= dt-pub-year=2013 dt-pub=20130722 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Positioning device for outdoor mobile robots using optical sensors and lasers en-subtitle= kn-subtitle= en-abstract= kn-abstract=We propose a novel method for positioning a mobile robot in an outdoor environment using lasers and optical sensors. Position estimation via a noncontact optical method is useful because the information from the wheel odometer and the global positioning system in a mobile robot is unreliable in some situations. Contact optical sensors such as computer mouse are designed to be in contact with a surface and do not function well in strong ambient light conditions. To mitigate the challenges of an outdoor environment, we developed an optical device with a bandpass filter and a pipe to restrict solar light and to detect translation. The use of two devices enables sensing of the mobile robotfs position, including posture. Furthermore, employing a collimated laser beam allows measurements against a surface to be invariable with the distance to the surface. In this paper, we describe motion estimation, device configurations, and several tests for performance evaluation. We also present the experimental positioning results from a vehicle equipped with our optical device on an outdoor path. Finally, we discuss an improvement in postural accuracy by combining an optical device with precise gyroscopes. en-copyright= kn-copyright= en-aut-name=NagaiIsaku en-aut-sei=Nagai en-aut-mei=Isaku kn-aut-name=iɍ kn-aut-sei=i kn-aut-mei=ɍ aut-affil-num=1 ORCID= en-aut-name=YamauchiGenki en-aut-sei=Yamauchi en-aut-mei=Genki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NagataniKeiji en-aut-sei=Nagatani en-aut-mei=Keiji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=WatanabeKeigo en-aut-sei=Watanabe en-aut-mei=Keigo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YoshidaKazuya en-aut-sei=Yoshida en-aut-mei=Kazuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=RȊw affil-num=2 en-affil= kn-affil=Graduate School of Engineering, Tohoku University affil-num=3 en-affil= kn-affil=Graduate School of Engineering, Tohoku University affil-num=4 en-affil= kn-affil=Department of Intelligent Mechanical Systems , Okayama University affil-num=5 en-affil= kn-affil=Graduate School of Engineering, Tohoku University en-keyword=mobile robot kn-keyword=mobile robot en-keyword=position estimation kn-keyword=position estimation en-keyword=laser speckle pattern kn-keyword=laser speckle pattern en-keyword=optical sensor kn-keyword=optical sensor END