International Journal of Computing and Digital Systems ISSN (2210-142X) Int. J. Com. Dig. Sys. 12, No.1 (Oct-2022) https://dx.doi.org/10.12785/ijcds/120180 A Decentralized Coordination Algorithm for Patrolling and Target Tracking in Internet of Robotic Things (IoRT) using Dynamic Waypoints and Self-triggered Communication Janardan Kumar Verma 1 and Virender Ranga 2 1 Department of Computer Engineering, National Institute of Technology, Kurukshetra, Haryana, India 2 Department of Information Technology, Delhi Technological University, Delhi, India Received 22 Jan. 2021, Revised 15 Jul. 2022, Accepted 23 Jul. 2022, Published 31 Oct. 2022 Abstract: The Internet of Robotic Things (IoRT) deals with autonomous objects such as robots and sensors together. It can be used for efficient patrolling and target tracking; however, mobile sensors (robots) must coordinate to decide their optimal actions. This paper proposes a decentralized coordination strategy that can enable multiple robots to perform both patrolling and target tracking in the deployed scenario. The basic idea is that the whole site is divided into local zones, and a single robot is deployed in each zone. All robots are logically divided into two groups, namely category C1 and category C2 robots. A dynamic waypoint generation algorithm is proposed to assist category C1 robots in the perimeter patrol. It produces the waypoints such that certain locations can be prioritized and intruders cannot predict the patrolling trajectory. Category C2 robots are responsible for area patrolling within the zone. Here, we also propose a strategy such that the places with a high probability of unusual acts can be visited frequently. We use the distributed Extended Kalman filter (EKF) to estimate and predict the position of the targets. Each robot has a self-triggered communication mechanism to share the necessary information with the neighbors, such as the estimated position of the intruder, EKF parameters, asking for help, etc. We have also developed an Internet of Thing (IoT) based web application to monitor and control the robots. In this app, robots subscribe to the server for necessary information and commands and publish their position, patrolled area, intruders’ position, battery status, etc., to the server for real-time monitoring and control. The proposed solution is validated through simulations in the Robot Operating System (ROS) and Gazebo. The results show the patrolling and target tracking performance using idleness and error in the target’s estimated position, respectively, as metric. Keywords: Cooperative target tracking, Cooperative patrolling, Internet of Robotic Things Coordination, Multi-Robot System, Multi-Robot Coordination. 1. Introduction Nowadays, the expedite advancements in Multi-Robot Systems (MRS) are motivated by robotics’ progress and cooperative behavior present in various living beings such as flocks of birds, fish swarm, etc. An increasing interest in the MRS coordination [1] research domain for monitoring and surveillance applications [2] such as mapping and exploration, monitoring wildfire and envi- ronment, security, and disaster management has emerged. The multi-robot systems employ robot groups that com- municate and execute various tasks need to coordinate. The mobility aspect of mobile robots enhances their inherent sensor coverage and renders supervision in areas where the deployed static nodes do not provide adequate coverage. Therefore, the combination of static sensors and MRS i.e. IoRT [3],[4] offers additional benefits, enhanced efficiency, and broader application domains. Deploying networked MRS [5], [6] and static sensor networks [7], [8] are two popular ways for tracking mobile targets. The robots detect and track the moving target by sharing the target’s information with neighbor robots. These robots estimate the target’s position as the tracking destination and regulate their motion towards it. Along with target tracking, this paper focuses on engaging multi-robots in the patrolling problem also. In patrolling problems, robots monitor the environment for a longer extent of time. They move and sense the envi- ronment for any unusual activity. In some cases, they can collect data from the deployed sensors in the environment and transmit the captured data to the base station for further actions. Integrating of patrolling and tracking can provide various benefits such as: when the intruder is detected by patrolling team there is no need of additional communication and team to track, it can enhance the response time of the action taken on the intruder, and it eliminates the need for separate detection system to send alert when intruder enters the zone. Combining tracking and patrolling is widely applicable in civilian, military environments such as surveillance around a sensitive site, house, livestock farms, for security at airport, etc. E-mail address: janardan18@gmail.com, virenderranga@dtu.ac.in http://journals.uob.edu.bh