Hemanshu Pota

... Actually, it frequently occurs that Gless's function offers better results for stability judgment under a system disturbance such as faults on transmission lines. The other is to simplify determination of the desired coefficients. ... [P(x,x)]Tdx Jo = r [F(X))Tdx Jo (7) ...

This paper presents a streamlined approach to future Precision Autonomous Farming (PAF). It focuses on the preferred specification of the farming systems including the farming system layout, sensing systems and actuation units such as tractor-implement combinations. The authors propose the development of the Precision Farming Data Set (PFDS) which is formed off-line before the commencement of the crop cultivation and

Abstract Proposes a special type of colocated feedback controllers for flexible structures. The controllers are a parallel combination of high-Q resonant circuits. Each resonant circuit is tuned to a pole (or the resonant frequency) of the flexible structure. Experimental results ...

ABSTRACT Traditional distribution networks were not originally designed to accommodate power generation facilities. The installation of distributed generation (DG) units with significant capacity in these passive networks can cause reverse power flows which will result in some conflicts with the operation of the existing protection system. In this context, utilities around the world have started establishing requirements to ensure safe and reliable interconnection of generators in low- and mediumvoltage networks. Grid interconnection is presently one of the most important issues involving DG. This paper presents a critical review of the requirements adopted by distribution companies in selected countries such as the USA, the UK, Germany and Australia to facilitate the connection of DG. Critical issues such as voltage regulation, islanding operation, dynamic interactions among DG and loads are discussed to identify a few points where attention is still needed to improve the reliability of distribution systems.

This paper presents a novel compensation method for the coupled fuselage-rotor mode of a Rotary wing Unmanned Aerial Vehicle (RUAV). The presence of stabilizer bar limits the performance of attitude control of an RUAV. In this paper, a positive position feedback (PPF) is introduced to increase the sta- bility margins and allow higher control bandwidth. The identified model is used

This paper addresses the problem of designing an output feedback decentralized control of intercon- nected power systems under large changes in real and reactive loads that cause large structural changes in the system model. The controller uses only the speed of the generator as its input. On load tap changers are also incorporated in the model and in the controller design. The design is carried out within a large-scale Markov jump parameter systems framework. This has allowed for a robust guaranteed performance con- troller to be designed. Simulations were carried out to eval uate the performance of the designed controller and to compare it with state feedback controllers.

ABSTRACT There are several advantages of using linear differential inclusions (LDIs) to describe nonlinear systems and other types of complex systems (such as, systems with time-varying uncertainties and/or saturation). From the control point of view, for example, it may be easier to design a controller for a nonlinear system by using a linear description of it in the form of an LDI (instead of using the nonlinear equations for the same purpose). With this premise, we focus on modeling of a class of nonlinear systems via a norm-bounded LDI (NLDI) model. One of the main contributions of the proposed modeling approach is the use of the mean-value theorem to represent the nonlinear system by a linear parameter-varying (LPV) model, which is then mapped into a polytopic LDI (PLDI) within the region of interest. To avoid the combinatorial problem that is inherent of polytopic models for medium- and large-sized systems, the PLDI is transformed into an NLDI, and the whole process is carried out ensuring that all trajectories of the underlying nonlinear system are also trajectories of the resulting NLDI within the operating region of interest. Furthermore, it is also possible to choose a particular structure for the NLDI parameters to reduce the conservatism in the representation of the nonlinear system by the NLDI model, and this feature is also one of the main contributions of this paper. A numerical example is presented at the end of this paper to demonstrate the effectiveness of this approach.

ABSTRACT This paper presents the design and implementation of a multi-variable double resonant controller with a multivariable integral controller on the piezoelectric tube scanner (PTS) of an atomic force microscope (AFM) to damp the resonant mode of the scanner, reduce the cross coupling between the axes of the scanner, increase the bandwidth of the overall closed-loop system, and improve the high speed imaging performance of the AFM. The lateral and longitudinal positioning system of the PTS is treated as a multi-input multi-output system and the system is identified by using the measured open-loop data. The controller parameters are obtained by minimizing the H2 norm of the difference between the desired and the actual closed-loop transfer function and the performance improvement achieved by the proposed controller is shown by comparing the scanned images obtained by implementing the proposed controller and the built-in proportional-integral (PI) controller of the AFM.

ABSTRACT This paper presents the design and implementation of a multi-variable combined resonant and integral resonant controller for the piezoelectric tube scanner (PTS) of an atomic force microscope (AFM) to damp the resonant mode of the scanner, reduce the cross coupling effect between the axes of the scanner, increase the bandwidth of the overall closed-loop system, and improve the high speed imaging performance of the AFM. The lateral and longitudinal positioning system of the PTS is treated as a two-input two-output system and the system is identified using measured open-loop data. The value of each parameter of the proposed controller is determined by minimizing H2 norm of the difference between the desired and the actual closed-loop transfer function. The performance improvement achieved by the proposed controller is presented by comparing scanned images obtained by implementing the proposed controller and the built-in proportional-integral (PI) controller of the AFM.

ABSTRACT This paper presents a design of a controller using two velocity feedback controllers (VFCs) and an integral controller for a piezoelectric tube scanner (PTS) of an atomic force microscope (AFM) to improve the high speed imaging performance of the AFM by damping the first resonant mode of the PTS and increasing the bandwidth of the closed-loop system. The design of VFC to damp the first resonant mode of the PTS is based on a mixed negative-imaginary and small-gain approach. The X- and Y-axis dynamics of the PTS are treated as two independent single-input singleoutput systems and the systems are identified from measured open-loop data. The performance improvement achieved by the proposed controller is presented by comparing the scanned images obtained by implementing the proposed controller and the built-in proportional-integral (PI) controller of the AFM.

Lack of good design tools have made designing, modeling, and control of long reach, light weight, ultrahigh-speed robotic structures extremely difficult. This paper describes a research effort towards development of a comprehensive design tool to study the dynamic behavior of flexible robotic structures. The graphical simulation and animation environment presented will help researchers to design and evaluate alternate geometries and

In this paper, we address the design of an autopilot for autonomous landing of a helicopter on a rocking ship, due to rough sea. A tether is used for landing and securing a helicopter to the deck of the ship in rough weather. A detailed nonlinear dynamic model for the helicopter is used. This model is underactuated, where the rotational

This paper investigates small-signal stability of a distribution system with distributed generator and induction motor load, as a dynamic element. The analysis is carried out over a distribution test system with different types of induction motor loads. The system is linearised by the perturbation method. Eigenvalues and participation factors are calculated to see the modal interaction of the system. The study indicates that load voltage dynamics significantly influence the damping of a newly identified voltage mode. This mode has frequency of oscillation between the electromechanical and subsynchronous oscillation of power systems. To justify the validity of the modal analysis time domain simulation is also carried out. Finally, significant parameters of the system that affect the damping and frequency of the oscillation are identified.

ABSTRACT This paper presents the design and implementation of a resonant controller for the piezoelectric tube scanner (PTS) of an atomic force microscope (AFM) to damp the first resonant mode. The dynamics of the PTS is identified by using the measured data and the “mixed” negative-imaginary and small-gain approach is used to establish the internal stability of the interconnected systems. The experimental results demonstrate the performance improvement achieved by the proposed controller.

The use of doubly fed induction generators (DFIGs) in large wind energy conversion systems (WECS) has significantly increased during the last few years. The DFIG is interfaced to the AC network through a grid side voltage source converter (GSC) and a rotor side voltage source converter (RSC) to enable the variable speed operation of the wind turbine. Moreover, it provides reactive power support to the AC grid during disturbances. The sensitivity of DFIGs to external faults has motivated researchers to investigate the impact of various grid disturbances, such as voltage sag and short circuit faults, on the low voltage ride through (LVRT) capability of DFIGs. However, no attempts have been made to investigate the impact of converter internal faults on the LVRT of the DFIG-based WECS. In this paper, the impact of a fire-through fault when it occurs in the RSC on the DC-capacitor voltage, rotor current, and the LVRT capability of the DFIG is investigated. A STATCOM controller to mitigat...

ABSTRACT This paper proposed a novel multi-input multi-output (MIMO) linear zero dynamic controller (LZDC) for a three-phase grid-connected photovoltaic (PV) system. The relative degree is investigated through the concept of Lie derivative to execute the LZDC for three phase grid connected PV system. To implement the control theory, system stability is checked by the LZDC scheme. The linear zero dynamic control law is obtained to control the injected power into the grid through the system's inverter. Finally, the simulation results are presented to show the performance of MIMO LZDC scheme with weather disturbances such as 10%, 20%, and 30% sunshade on the PV strings and also proved that the system operated at the unity power factor.