Locating Algorithm for the Indoor Robot based on Li-Fi Using the Multi-Beam


Pham Minh Trung*, Minwoo Lee**, Jinyeong Choi***, Jaesang Cha****


Seoul National University of Science and Technology

232, Gongneung-ro, Nowon-gu, Seoul, Republic of Korea

Seoul, Republic of Korea

trungpm.bkk54@gmail.com, alsdnya@gmail.com, choijinyeongs@gmail.com, chajs@seoultech.ac.kr





Nowadays, the emergence of mobile robots is very common in public places such as guiding robots in museums, galleries, military and family reconnaissance robots such as vacuum cleaners or systems family support. For robots to operate independently, positioning is the first and most important requirement, and now there are some very popular positioning methods such as GPS that are well suited for outdoor use, but The error of this method is very large when used indoors environments where space is limited. So, this paper proposed a new positioning method is “Locating Algorithm for Indoor Robot based On Li=Fi Using the Multi-Beam”. The proposed algorithm can work special LED lighting that is indispensable for indoor use. The present position can be estimated on the basis of the direction and data of the signal received from the photo diode that can be receive light signal.


Keywords –Robot, Li-Fi, Locating Algorithm, Multi-Beam, Indoor Positioning


1. Introduction


There have been many methods of localization that have been studied and applied to in-house robots such as infrared sensors, lasers, wireless, RFID radio wave which one of the major solutions for robot positioning. Today, with the launch and development of the LED, along with the Li-Fi communication technology [1]. Locating the robot based on Li-Fi technology is considered a promising method with more advantages than the wireless positioning technology using RF or Wi-Fi. Li-Fi technology has little impact on human health and incorporates lighting purposes. In addition, the LED lamp has a high lifespan of 100,000 hours and low cost allows the deployment of Li-fi navigation system without much cost.

So, In This paper proposed Locating Algorithm for the Indoor Robot based on Li-Fi Using the Multi-Beam. The proposed algorithm substitutes GPS, which is hard to operate indoors, with special LED lighting that is indispensable for indoor use. The present position can be estimated on the basis of the direction and data of the signal received from the photo diode that can be receive light signal.

The order of this paper is as follows. Chapter 1 introduces the background of this study, in Chapter 2, we describe the related technical research and the proposed algorithm. Finally, we conclude this paper in Chapter 3.


2. Proposed Algorithm


The typical WxLxH  room model is assumed to build a lighting system and incorporate wireless communication (Li-fi) using visible light in the indoor environment, communication model with transmitter station access points with directional beams arranged evenly across the ceiling of the room [2]. Each transmitter station is an array of LEDs for illumination and data transmission, specially designed to include direction lights cluster (Beam), which have a beam  in the middle and perpendicular to the ceiling, and  The remaining light beam is placed around the central beam with different angles so that each transmitter station covers a fixed area in the room [3]. With such a transmitter station configuration, in order to maintain continuous data transfer and to ensure uniform lighting throughout the room, two issues were identified in the design:

- Ensure there is no blind area between the areas of the light beams in the same light station.

- Ensure there is no blind area between the areas covered by the light stations.

In this positioning system, the receiver station is simply designed to consist of 1 PD (Photodiode) directly attached to the robot to receive signals from the transmitter station, and a Gyro sensor to determine the direction of movement of the robot and the coordinates of the receiver station can be determined. The beams will be transmitted sequentially at a frequency of 24 times per second, and each broadcast will contain information on the light beam, each of which beams contains information about the transmitter, including the sequence number and coordinates of the central beam, information about the coordinates of the beam. 

In order to be able to locate the robot, we will design a multi-beam light transmitter, which will be designed so that the light beams are small enough, each light beam is transmitted at a frequency of 24 times / s and is broadcast sequentially containing information about the light beam. Therefore, the station receiver can scans the coordinates of the robot.

Thanks to the support of Li-fi technology, users can monitor the LED system and move the robot through the control screen. When one of the transmitters or receivers is inactive, the robot's moving sensor fails, the system alerts the fault by sending the data to the control center and immediately the system is processed in time.


3. Conclusion


In this paper, we propose locating algorithm for the indoor robot based on Li-Fi using the multi-beam which supports indoor positioning using wireless solution used LED lighting and Photo Diode.

Using Locate the indoor robot based on Li-fi using the multi-beam to increase the accuracy of positioning, with the advantage of a compact design receiver, it is easy to integrate with small mobile devices such as telephones and the system can be controlled and operated automatically via a Li-fi network. However, the disadvantage of this method is that the transmitter structure is relatively complex, but it achieves high accuracy. In the future, it will be applied to large-scale complex buildings such as large shopping mall and intelligent building, and it will be used as a valuable feed for effective indoor location recognition and indoor self-driving. In addition, the proposed algorithm can be utilized as a large-scale indoor location estimation and network configuration solution based on the cloud network in conjunction with the IoT solution.



This work was supported by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (No.2017-0-00218, International Standardization Research of VLC Application Technology based LiFi and CamCom).




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