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The design of a decentralized control scheme is presented which is capable of counteracting voltage variations and offering the ancillary service of voltage regulation to the Distribution Network (DN) by acting on reactive and active power injections of Distributed Energy Resources (DERs). The design is based on a complete dynamic Multi-Input Multi-Output (MIMO) model of the distribution system with different types of DERs interfaced to the DN by inverters. Each DER is equipped with a state–feedback controller and two standard regulators of type PI and I, which realize the dynamic voltage adjustment, ensure null regulation error of voltage and active power at the Point of Common Coupling (PCC) and guarantee robust stability. This control objective is achieved without communication links among the local controllers and in presence of parameters uncertainty affecting the MIMO model. Finally, the proposed approach is validated by dynamic simulations on the IEEE 123 node test feeder with 15 additional DERs of three different types in presence of different scenarios of the distribution system, inaccuracy of the DN line parameters and voltage sags. [ABSTRACT FROM AUTHOR]

Distributed generation, which is installed to exploit renewable energy sources, can also be used as a reactive power resource and contribute to tackle the voltage regulation problem in smart distribution grids. Adopting a decentralized approach with off-line coordination, the paper proposes an optimal set-point design for the voltage/reactive power control scheme of distributed generation. The objective is to improve the voltage profile along the feeders of a distribution system. Using only local measurements, the actual operating conditions of the feeder are firstly estimated; then, the set-point is evaluated by solving an optimal voltage profile problem. The off-line coordination avoids any modification to the architecture of existing control systems and requires communication only in the case of significant changes of the distribution system topology. The results of numerical simulations are presented for MV feeders with wind and photovoltaic generations. A comparison with standard control schemes is reported, as well as considerations about the off-line coordination among the distributed generations and the tap-changer of the HV/MV transformer. [ABSTRACT FROM PUBLISHER]

This paper presents the adaptive design of an automatic voltage regulator (AVR) control scheme for synchronous generators that is capable of providing satisfactory voltage control performance in the presence of unknown variations of the power system operating conditions. The design is articulated in four steps: voltage and current phasor estimation, estimation of the parameters of the Thevenin equivalent circuit adopted to rep- resent the power system response using a steady-state model, determination of the sampled-data transfer function of the system, and AVR design developed according to discrete-time techniques. A suitable procedure is described to derive the sampled-data transfer function of the system starting from models of the power system, synchronous generator, and exciter. The obtained transfer function depends on the estimated parameters yielded by a recursive least-squares algorithm subject to constraints deriving from the Thevenin circuit. The AVR design is based on the pole-assignment technique while the phasors estimation is performed by two Kalman filters. Finally, the results of accurate numerical simulations conducted for a test network are reported, comparing the performance of the proposed adaptive control scheme to the one of a PID controller with fixed parameters. [ABSTRACT FROM AUTHOR]

One important problem in autonomous robot navigation is the effective following of an unknown path traced in the environment in compliance with the kinematic limits of the vehicle, i.e., bounded linear and angular velocities and accelerations. In this case, the motion planning must be implemented in real-time and must be robust with respect to the geometric characteristics of the unknown path, namely curvature and sharpness. To achieve good tracking capability, this paper proposes a path following approach based on a fuzzy-logic set of rules which emulates the human driving behavior. The input to the fuzzy system is represented by approximate information concerning the next bend ahead the vehicle; the corresponding output is the cruise velocity that the vehicle needs to attain in order to safely drive on the path. To validate the proposed algorithm two completely different experiments have been run: in the first experiment, the vehicle has to perform a lane-following task acquiring lane information in real-time using an onboard camera; in the second, the motion of the vehicle is obtained assigning in real-time a given time law. The obtained results show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

For a mobile robot, odometry calibration consists of the identification of a set of kinematic parameters that allow reconstructing the yes hide's absolute position and orientation starting from the wheels' encoder measurements. This paper develops a systematic method for odometry calibration of differential-drive mobile robots. As a first step, the kinematic equations are written so as to underline linearity in a suitable set of unknown parameters; thus, the least-squares method can be applied to estimate them. A major advantage of the adopted formulation is that it provides a quantitative measure of the optimality of a test motion; this can be exploited to drive guidelines on the choice of the test trajectories and to evaluate accuracy of a solution. The proposed technique has been experimentally validated on two different mobile robots and, in one case, compared with other existing approaches; the obtained results confirm the effectiveness of the proposed calibration method. [ABSTRACT FROM AUTHOR]

Presents a systematic approach to self-tuning regulator design for nodal voltage waveform control in electrical power systems by means of shunt power electronic devices. Use of Kalman filtering technique to estimate the voltage and current phasors at fundamental and harmonic frequencies; On-line parameter identification of the Thevenin equivalent circuits that represent the electrical power system at each phasor frequency.

Proposes an approach to the design of control laws for underwater vehicles that takes into account the hydrodynamic effects affecting the tracking performance. Representation of attitude errors through quaternions; Stability of the designed control law through Lyapunov-based argument.

The presence of joint velocity and acceleration limits must be taken into account by the inverse kinematics of robot manipulators, so as to avoid incorrect task execution when these are violated. To solve this problem, a novel algorithmic approach to kinematic control is presented in this paper, which guarantees that the joint variables do not overtake their limits. The proposed technique is based on a new second-order inverse kinematics algorithm, which enables the handling of velocity and acceleration constraints while tracking the desired end-effector path. The goal is achieved by suitably slowing down the task-space trajectory via a time warp when joints limits are encountered. The proposed method is designed for on-line applications, i.e., the desired trajectory is not known in advance, and requires a light computational burden. The application of the proposed approach is finally illustrated in experiments implemented on a six-degree-of-freedom industrial robot manipulator. [ABSTRACT FROM AUTHOR]

Proposes a constrained least squares methods for on-line parameter identification of power system steady-state equivalent circuits. Determination of both equivalent impedances and ambient voltage harmonics by the proposed on-line identification procedure; Fundamental and harmonic frequencies of Tehevenin equivalent circuit parameters.