Publications
Learning Decentralized Controllers for Segregation of Heterogeneous Robot Swarms with Graph Neural Networks
International Conference on Manipulation, Automation, and Robotics at Small Scales (MARSS), Toronto, Canada.
Abstract Full PaperIn this paper, we studied the problem of finding decentralized controllers for large-scale heterogeneous robot swarms exhibiting segregative behaviors. As seen in nature, Segregative behaviors involve sorting a group of robots into groups based on their type. Our approach involves learning controllers that utilize local information at test time by imitating the policy of a centralized controller based on a differential potential concept at training time. We parameterized our policy using a time-varying aggregation graph neural network with multi-hop communication. This incorporates information not only from immediate neighbors but distant neighbors. We showed that our controller outperformed a local controller that considers only immediate neighbors and achieved similar performance to the centralized controller through varied experiments. In addition, we demonstrated the scalability of our method by exploring larger swarms and different groups.
UAV Visual-Inertial Dynamics (VI-D) Odometry using Unscented Kalman Filter
IFAC-PapersOnLine, Volume 54, Issue 20, 2021, Pages 814-819, ISSN 2405-8963.
Abstract Full PaperDifferent approaches to Visual-Inertial odometry(VIO) has been presented in literature. However, few research works exploits the quadrotor translational and rotational dynamics and the known thrust and torque inputs. Additional information from the dynamics with known control inputs improves the state estimation. This paper is focused on the estimation of the quadrotor UAV 6 DOF pose by fusing the information from the dynamics of the quadrotor coupled with visual-inertial measurements using an Unscented Kalman Filter. The thrust and torque inputs drives the prediction model while the VIO system provides 6 DOF pose, velocity and unbiased angular velocity of the vehicle. The results shows that our approach improves the state estimates by about 2-5% in translation and 37% in rotation.
Distributed Quadrotor UAV Tracking using a Team of Unmanned Ground Vehicles
,American Institute of Aeronautics and Astronautics Scitech 2021 Forum.
Abstract Full PaperIn this paper, we present an algorithm to optimally track a non-cooperative quadrotor using a team of Unmanned Ground Vehicles (UGVs) which are equipped with GPS as well as radar capable of sensing range, azimuth angle and elevation angle measurements. First, a distributed information filter algorithm is developed for each UGV to locally estimate the position and velocity of the quadrotor using its information and information from neighboring UGVs. We then fuse the information from various UGVs using a Consensus Filter such that their estimate of the state of the quadrotor converges. However, the accuracy of the estimation by the consensus filter depends upon the relative position of the sensors. Hence, it is necessary to design a control policy that leads to optimum configuration of UGVs in order to maximize the utility of measurement. A Model Predictive Controller(MPC) is developed to optimally control the UGVs to improve the state estimation. By defining a proper cost function and optimization algorithm in MPC, we are able to control the path of UGVs to increase the accuracy of estimating the position and velocity of a non-cooperative quadrotor.
Robot Navigation Model in a Multi-Target Domain Amidst Static and Dynamic Obstacles
,Proceedings of the IASTED International Conference Intelligent Systems and Control (ISC 2018) (pp. 44-51)
Abstract Full PaperThis paper presents an efficient robot navigation model in a multi-target domain amidst static and dynamic workspace obstacles. The problem is that of developing an optimal algorithm to minimize the total travel time of a robot as it visits all target points within its task domain amidst unknown workspace obstacles and finally return to its initial position. In solving this problem, a classical algorithm was first developed to compute the optimal number of paths to be travelled by the robot amidst the network of paths. The principle of shortest distance between robot and targets was used to compute the target point visitation order amidst workspace obstacles. A hybrid modelling scheme premised on geometrical considerations was applied to determine the length of obstacles encountered by the robot. Also, a dynamic model premised on the collapse of the radiation cone was proposed and used to estimate the velocity of a dynamic obstacle along the robot’s path.
Selected Projects
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Telehealth Drone
News
Designed the software stack for keyboard control and obstacle avoidance of an indoor remotely semi-piloted unmanned aerial vehicle for medical supplies delivery.
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Filtering, Localization and SLAM algorithms for mobile robots
CodeThis repo includes kalman filter, extended kalman filter, unscented kalman filter, EKF/UKF localization with and without unknown landmarks and EKF SLAM implementation from the book "Thrun, S., et al. Probabilistic robotics."
Introduction to Applied Artificial Intelligence and Machine Learning Tools using Scikit Learn
CodeThis repo includes different algorithms I implemented during my class. It includes linear and logistic regression, minimum distance classifier (MDC), k-Nearest Neighbors and Neural networks using sklearn.
Final Project Overview: Classification of audio signals digits 0-9 using different machine learning techniques.

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ROS Wrapper for Adafruit LSM9DS1 IMU
Code This is a ROS package for publishing Adafruit LSM9DS1 9DOF IMU data on Jetson Nano using i2c.