Browsing by Author "Kumara, KJC"

Now showing 1 - 3 of 3

item: Conference-Full-text
Development of low-cost wireless sensor network and online data repository system for time synchronous monitoring of civil infrastructures
(IEEE, 2020-07) Vishnu, P; Lewangamage, CS; Jayasinghe, MTR; Kumara, KJC; Weeraddana, C; Edussooriya, CUS; Abeysooriya, RP
Advances in wireless sensor networks (WSN) are well proven and commonly used in Structural Health Monitoring (SHM). SHM using WSN is the modern paradigm which incorporates automated systems for data acquisition, in monitoring, analysis, and identification of structural responses and defects. Even though currently used WSN are economical compared to tethered monitoring systems, it is still unaffordable. The costly nature of traditional data loggers and the low penetration nature of currently used networking protocols, through civil structures thus requiring dense array of sensors, increase the overall cost of a WSN. This paper discusses the development of a low cost WSN to monitor the acceleration response of civil engineering structures using off the shelf products. The developed system is capable of capturing synchronous acceleration response data with the sampling frequency of 100 Hz with a resolution of 0.5 mg. The collected data is processed and shared between peer nodes using sub 1 Gigahertz wireless protocol, and stored within an online based central data repository system replacing traditional data loggers. The developed low cost WSN is proved to be a better low cost alternative in the context of a target building with 48 floors (185 m height).
item: Conference-Full-text
Flight dynamics of a 'v' shape boomerang: effect of wind on boomerang trajectory
(IEEE, 2023-12-09) Rajathurai, R; Kumara, KJC; Baduge, S; Abeysooriya, R; Adikariwattage, V; Hemachandra, K
Boomerangs have captured attention because of the mechanical structure that realises such complex movements of the boomerang. The perfect prediction of the path leads to the application of boomerangs in the field. The external environment is always unsteady; therefore, the dynamics of boomerangs should be studied in unsteady wind conditions. The main aim of this research is to study the steady and unsteady wind effects on the boomerang trajectory by developing an unsteady input-based mathematical model. A traditional 'V' shape boomerang is designed using CATIA V5, and 2D steady state ANSYS Computational Fluid Dynamics Simulation (CFD) was performed to derive the aero dynamical coefficients of the boomerang. Finally, the newly developed mathematical model is numerically simulated using MATLAB. The trajectory of the boomerang in different wind conditions is plotted and compared. The results show that the steady and unsteady wind highly influences the boomerang path. Results show the capabilities of the model under both the steady and unsteady flow of wind in predicting a boomerang trajectory.
item: Thesis-Abstract
Modeling and control of a surface vessel for "ITS for the Sea" applications
Kumara, KJC; Kumarawadu, S; De Silva, PSN
In the emerging field of intelligent transportation systems (ITS), ''TS for the sea'' refers to the area of maritime traffic. Automated vehicle control systems are a key technology for ITS. An autonomous surface vessel (ASV) can be defined as a vehicle controlling its own steering and speed for Navigation, dynamic positioning, motion stabilization and obstacle detection and avoidance. The scope of the research is defined by two main objectives viz. developing complete mathematical model of a surface vessel by analyzing hydrodynamic forces and main other effects arising when manoeuvring in the ocean, and design online-learning adaptive controller for path tracking and speed control using real control inputs; propeller thrust and steering angle. The vessel moves in a hydrodynamic environment where many uncertainties, non-linear and non-predictive behaviours always appear. The ocean vehicle is modelled mathematically using first principles and derivations wherever possible. In this work, the problem of control with guaranteed sway and yaw stability for automated surface vessel operation is addressed with special emphasis on speed control. A control scheme to solve this problem without simplifying the dynamics is proposed and extensively studied using formative mathematical analyses and simulations. The main academic motivation of this research was to study and synthesis the power of artificial intelligence techniques in controlling of non-linear dynamical systems with online-learning and adaptive capabilities. A model-based neural network adaptive controller is developed blending a self adaptive neural network module and a classical Proportional plus Derivative (PD)-like control to obtain optimum control performance by complementing each other. The adaptive neural module counteracts for inherent model discrepancies, strong nonlinearities and coupling effects.