Positioning and guiding educational robots by using fingerprints of WiFi and RFID array

Luo et al. EURASIP Journal on Wireless Communications and Networking (2018) 2018:170 https://doi.org/10.1186/s13638-018-1183-5 RESEARCH Open Access Positioning and guiding educational robots by using fingerprints of WiFi and RFID array Wenxing Luo1,2*, Xu Deng1, Feiqing Zhang1, Youmei Wen2 and Dheyaa Jasim Kadhim1 Abstract Positioning educational robots in the indoor ambiance is an important and basic function for robots to provide intelligent educational services for users, and it is still an open challenge problem. This paper proposes to position indoor robots by using fingerprints of wireless fidelity (WiFi) and radio-frequency identification (RFID) array in the complementary way. The fingerprint of WiFi is first used to position educational robots (Erob) in a large area and to guide robots to a place close to the target location. Then, the fingerprint of RFID array is used to guide Erob to the target location with a small discrepancy. It proved that the designed layouts of WiFi devices and RFID array can have fingerprint matching to estimate the position of Erob. The proposed positioning method can guide Erob to the target location fast and accurately so that robots can provide multiple services based on it. Keywords: Erob, WiFi, RFID, Fingerprint positioning, RSS 1 Introduction Scientific research is an important force in promoting the development and progress of human society. Robots and artificial intelligence rise again. Humanoid robot is the main development direction of robot. From assistant robot to co-worker, co-robot, until Cobot, many specific requirements are put forward in practical applications, which promotes the progress of the research [1]. Developing educational robots has become an active research direction due to the related technologies which have a great of advance in the past decades. Positioning educational robots is one of important tasks, because it is the critical technology for robots to provide the intelligent services. Accurating and pervasiving indoor positioning can significantly improve our everyday life [2]. Educational robots must have positioning ability so that they move to the target locations to provide their services [3]. Positioning technology can also accurately guide the robot, in order to achieve autonomous recovery of the robot [4]. A lot of progresses have been achieved in developing positioning technologies and applications, but there is still much room for improvement. Robot navigation in urban environments has become an active area of research in recent * Correspondence: 1 National Engineering Research Center for E-Learning, Central China Normal University, Wuhan 430079, China 2 Department of Electronic Engineering, Qiannan Normal University for Nationalities, Duyun 558000, China years [5]. This paper’s target is to develop a positioning method to guide educational robots (our group’s self-developed educational robot, we call it Erob) to move to a target location in the indoor ambiance. Indoor positioning has received great attention recently because position information is essential for providing location-based services (LBSs) [6]. All of local communication technologies and some sensor technologies were applied in indoor positioning, which offers intelligent services in various fields, for example, Internet of Things, hospitals, garages, classrooms, etc. The references about ZigBee indoor positioning [7] were introduced. A large number of nodes should be arranged for indoor positioning, and each node also needs to supply power alone, and the network is complex, it is not suitable for positioning the educational robot in the classroom scenario. Many modern applications use RFID as a wireless non-contact method of data transfer to identify and track the objects to which the transponders are attached [8]. Passive tags can be used, which obtain the energy from the interrogating electromagnetic field created by RFID readers, and the transponders require no local power sources, such as batteries, which results in the reduced need for maintenance while achieving high flexibility, long lifetime, and low cost. RFID technology has been widely adopted in various industrial tracking and positioning applications [9]. RFID system has two main components, RFID tags and RFID readers [10]. In the logistics, © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Luo et al. EURASIP Journal on Wireless Communications and Networking (2018) 2018:170 transportation and indoor positioning areas have great application. WiFi-based positioning is another potential technology for indoor navigation, because it only uses per-existing WiFi infrastructures. WiFi positioning error does not accumulate with time which makes it a potential source to aid the stand alone navigation solution based on micro-electromechanical systems (MEMS) sensors [11]. WiFi hotspots are very popular in public areas because they can provide high data rates up to 11 Mbit/s (IEEE 802.11b) or 56 Mbit/s (IEEE 802.11a/g) [12]. WiFi positioning systems usually estimate the transmitter position using radio beacons involving several antennas and measuring the power of received signals [13]. WiFi positioning is one of the most ideal positioning technologies, and it is mainly used for moving target positioning in indoor environment. Indoor positioning faces many challenges, including location accuracy, cost, coverage range, latency, and the complexity of indoor environments resulting from multipath propagation and frequent environment changes [12], which can cause significant degradation in the accuracy of indoor positioning. Under the background of education information, many universities, primary and middle schools have started the campus wireless network construction, and most of them achieved seamless coverage of WiFi. In order to achieve low-cost and efficient educational robot positioning, we consider using campus WiFi signals to provide positioning services for Erob. In order to enable Erob to navigate and localize effectively in indoor environments, we take advantage of the integration of WiFi and RFID fingerprinting techniques to overcome the limitations of only RFID or WiFi positioning, at the same time, we use the wireless fingerprint technology to establish a large-scale (1 m) interval WiFi fingerprint and layout two access points (APs) on the wall. Through the offline stage of gathering fingerprint data and establishing the fingerprint database of the classroom, we also create RFID fingerprint map in front of the projection area, in which layout of the 11 passive tags array. The reader acquir (...truncated)