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In-spite of a number of in-depth investigations regarding the impact of clones in the maintenance phase there is no concrete answer to the long lived research question, “Does the presence of code clones increase maintenance effort?”. Existing studies have measured different change related metrics for cloned and non-cloned regions, however, no study calculates the maintenance effort spent for these...
A robust nonlinear adaptive controller design for unmanned autonomous vehicles (UAVs) for controlling the hovering flight is presented. The controller is premeditated recursively based on the control Lyapunov theory where the mass of the UAV in the model is considered as anonymous parameter. To illustrate the forcefulness property of the designed controller, the effects of external disturbances are...
A new direct power control (DPC) approach for a voltage source inverter (VSI) based three-phase grid-connected solar photovoltaic (PV) system is proposed in this paper. The proposed DPC is designed using the nonlinear backstepping control scheme based on the power dynamics rather than the conventional dp current dynamics. As a result, the inner current control loop is eradicated in this paper which...
This work presents a Simulink-based model of a photovoltaic (PV) system using a single-diode and two-diode model of solar cell. A comparison between the two-diode and single-diode model of PV cell has been illustrated. In addition, the output of series-parallel connection of PV cells has been examined. In the model, series and shunt resistances are calculated by an efficient iteration method based...
This paper presents a nonlinear control scheme to regulate the dc-link voltage for extracting the maximum power from PV system and the current to control the amount of injected power into the grid. The controller is designed using an adaptive backstepping technique by considering the parameters of the system as totally unknown. The control of power injection into the grid requires the regulation of...
In modern power electronic systems, DC-DC converter is one of the main controlled power sources for driving DC systems. But the inherent nonlinear and time-varying characteristics often result in some difficulties mostly related to the control issue. This paper presents a robust nonlinear adaptive controller design with a recursive methodology based on the pulse width modulation (PWM) to drive a DC-DC...
DC-DC power converters based on switched capacitor circuits are widely used to realize different power supply domains in SOC chips. They can be classified as Analog Mixed Signal circuits. Current approaches to their verification is primarily based on simulating their transistor level netlist in circuit simulators. In this paper an approach to formally verify them using simulation traces is proposed,...
A formal mathematical model of an Adaptive Cruise Controller (ACC)in SpaceEx is presented with a view to formally verify it to ensure its safety critical behavior. SpaceEx (an academic open source tool) is a hybrid systems modeling and verification platform which employs efficient implementation of reachability and safety verification algorithms which are scalable under certain assumptions, to circumvent...
A robust adaptive backstepping technique is proposed in this paper to solve the speed-tracking problem of a series DC motor for improving transient response. The parameters of DC motor are considered as unknown and the external disturbances are incorporated into the dynamical model. The proposed controller is designed in such a way that it is adaptive to the unknown parameters of series DC motor and...
Major Prerequisite to overcome the problem due to the insulation breakdown in High Voltage (HV) power apparatus is the efficient diagnosis of partial discharge (PD). Many different methods have been proposed by researchers for detection and measurement of PDs in past, based on different outcomes of PD such as Chemical, Acoustic, Electrical, Optical and Electromagnetic (EM) wave radiation. Among these,...
This paper presents a nonlinear control scheme to control the attitude of a small-scale rotary wing unmanned aerial vehicle (RUAV) in the presence of external disturbances. The proposed attitude controller is designed in such a way that it is robust to external disturbances. To prove the convergence of the attitude tacking error to zero, i.e., the actual attitude of the closed-loop system to reference...
Rural Distribution Systems (RDSs) are expanding abruptly day by day. With this continuous expansion, the distribution loss is increasing deliberately as a coherent parameter. Constructing single phase HT (high tension) line, it becomes more alarming with respect to loss as well as system management. This paper highlights the advantages of three phase tap lines for the reduction in line loss compared...
In this paper, a nonlinear backstepping controller is designed for three-phase grid-connected solar photovoltaic (PV) systems to share active and reactive power. A cascaded control structure is considered for the purpose of sharing appropriate amount of power. In this cascaded control structure, the dc-link voltage controller is designed for balancing the power flow within the system and the current...
This paper presents a nonlinear adaptive excitation control scheme to enhance the dynamic stability of multimachine power systems. The proposed controller is designed based on the adaptive backstepping technique where the mechanical power input to the generators and the damping coefficient of each generator are considered as unknown. These unknown quantities are estimated through the adaption laws...
This paper presents the performance study of a speed sensor-less control of grid connected DFIG based variable speed Wind Energy Conversion System (WECS). A new phase locked loop (PLL) based slip speed estimator using rotor current is proposed for speed sensor-less stator field oriented vector control operation of rotor side converter (RSC) to ensure decoupled control of stator active and reactive...
In this paper two types of sliding mode control (SMC): normal sliding mode control (normal-SMC) and Quasi sliding mode control (Quasi-SMC) are used in controlling single-link rotational base flexible manipulator for three different payloads. The dynamic equations of the system are done by using Lumped parameter method. Quasi-SMC is used for chattering elimination which is present in the case of normal-SMC...
This paper presents a comparative study of two control approaches; fuzzy proportional derivative control (PD) and sliding mode control (SMC) for a two degree of freedom (2-DOF) robot manipulator. It presents the implementation of both model based and model free based control. SimMechanics is used for modelling of the robot which requires a little knowledge regarding the dynamics of the system. A robust...
A comparative analysis on chattering based on Sliding Mode Controller (SMC) techniques for a single link flexible manipulator is presented in this paper. The proposed controller techniques include i) normal-SMC ii) Quasi-SMC iii) Asymptotic-SMC. These controllers are used in controlling the tip position as well as the tip deflection of the system. Lyapunov stability theory is used to achieve the stability...
Steam-valving and excitation systems play an important role to maintain the transient stability of power systems with synchronous generators when power systems are subjected to large disturbances and sudden load changes. This paper presents a nonlinear adaptive backstepping approach for controlling excitation and steam-valving systems of synchronous generators. In this paper, the proposed excitation...
A mathematical model based on macroscopic heat balance for surface ablation phenomenon and analytical temperature profile below the vapor cavity, has been developed to estimate the average effective spot diameter and predict depth of bead penetration as a function of the processing parameters during electron beam welding of AISI 304 stainless steel. The average beam spot diameter on the work piece...
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