Synthesis of a stabilizing control problem for a multimachine power system with phase shifter

A systematic procedure is considered for the synthesis of a stabilizing control method for a multimachine power system with phase shifter, taking into account the velocity governor. A new approach is presented, which uses a coordinate-transformation technique and an optimization technique. The application of this method to a stabilizing control problem for a power system is illustrated by considering a 3-machine power system with phase-shifter control, taking into account an additional control vector for the governing system with one time constant. The synthesized controls are then used to improve the power-system transient stability to a remarkable degree and to restore the power-system transients rapidly to the stable-equilibrium point. Numerical results arc given.     

Antenna stabilizing control system using a strapdown 2-axis Azimuth/Elevation method

A 2-axis antenna-stabilizing-control device that does not need a level sensor was developed. The control incorporates a zero-servo method, which zeros the two gyro outputs by rotating an antenna with both an azimuth motor and an elevation-servo motor. However, a Gimbal lock and unlapping of the cable frequently occur at a high-elevation angle, resulting in large pointing errors. We solved these problems by using the servo-error-correction method and the estimated rewind method.     

Simulation study for automatic generation control of a multi-area power system by ANFIS approach

This paper deals with the application of artificial neural network (ANN) based ANFIS approach to automatic generation control (AGC) of a three unequal area hydrothermal system. The proposed ANFIS controller combines the advantages of fuzzy controller as well as quick response and adaptability nature of ANN. Appropriate generation rate constraints (GRC) have been considered for the thermal and hydro plants. The hydro area is considered with an electric governor and thermal area is considered with reheat turbine. The design objective is to improve the frequency and tie-line power deviations of the interconnected system. 1% step load perturbation has been considered occurring either in any individual area or occurring simultaneously in all the areas. It is a maiden application of ANFIS approach to a three unequal area hydrothermal system with GRC considering perturbation in a single area as well as in all areas. The performance of the ANFIS controller is compared with the results of integral squared error (ISE) criterion based integral controller published previously. Simulation results are presented to show the improved performance of ANFIS controller in comparison with the conventional integral controller. The results indicate that the controllers exhibit better performance. In fact, ANFIS approach satisfies the load frequency control requirements with a reasonable dynamic response.     

A method for designing a stabilizing control for a class of uncertain linear delay systems

We present a simple method for designing stabilizing controllers for linear delay equations containing unmatched uncertainty. The methodology employed is based on differential inequalities rather than on Lyapunov stability theory.     

无线通讯系统功率控制算法及收敛性

利用随机逼近方法研究随机功率控制问题,将功率控制问题转化为寻求一个不确定函数零点的一个随机逼近问题.在承认随机噪声时,证明了所提出的算法在均方差意义下收敛到最优解.     

A method to find a stabilizing control for an accumulation fund with functions of an insurance company

We find financial injections that stabilize a stabilization fund and minimize the performance functional. In particular, we consider a quadratic functional that describes deviations of the capital stock from a certain trajectory.     

A nonholonomic control method for stabilizing an X4-AUV

A nonholonomic control method is considered for stabilizing all attitudes and positions (x, y, or z) of an underactuated X4 autonomous underwater vehicle (AUV) with four thrusters and six degrees of freedom (DOF), in which the positions are stabilized according to the Lyapunov stability theory. A dynamic model is first derived, and then a sequential nonlinear control strategy is implemented for the X4-AUV which is composed of translational and rotational subsystems. A controller for the translational subsystem stabilizes one position out of the x-, y-, and z-coordinates, whereas controllers for the rotational subsystems generate the desired roll, pitch, and yaw angles. Thus, the rotational controllers stabilize all the attitudes of the X4-AUV at the desired (x-, y-, or z-) position of the vehicle. Some numerical simulations are conducted to demonstrate the effectiveness of the proposed controllers.     

Turbine-generator system control for a HTGR power plant

Dual turbine-generator systems offer several operating advantages for large electric power generating plants. In order that these benefits be fully realized, it is necessary that the twin turbine-generator system, including its associated control systems, perform satisfactorily in a variety of normal and energy operating modes. This paper combines nonlinear simulation and linear multivariable systems analysis techniques to investigate system dynamic behavior and governor design. Specific results are reported for load following operation in which one turbine-generator is shut down.     

Geometric synthesis of a hybrid limit cycle for the stabilizing control of a class of nonlinear switched dynamical systems

This paper proposes a new constructive method for synthesizing a hybrid limit cycle for the stabilizing control of a class of switched dynamical systems in R², switching between two discrete modes and without state discontinuity. For each mode, the system is continuous, linear or nonlinear. This method is based on a geometric approach. The first part of this paper demonstrates a necessary and sufficient condition of the existence and stability of a hybrid limit cycle consisting of a sequence of two operating modes in R² which respects the technological constraints (minimum duration between two successive switchings, boundedness of the real valued state variables). It outlines the established method for reaching this hybrid limit cycle from an initial state, and then stabilizing it, taking into account the constraints on the continuous variables. This is then illustrated on a Buck electrical energy converter and a nonlinear switched system in R². The second part of the paper proposes and demonstrates an extension to Rⁿ for a class of systems, which is then illustrated on a nonlinear switched system in R³.     

New delay-dependent stability criteria and stabilizing method for neutral systems

This note concerns delay-dependent robust stability criteria and a design method for stabilizing neutral systems with time-varying structured uncertainties. A new way of deriving such criteria is presented that combines the parameterized model transformation method with a method that takes the relationships between the terms in the Leibniz-Newton formula into account. The relationships are expressed as free weighting matrices obtained by solving linear matrix inequalities. Moreover, the stability criteria are also used to design a stabilizing state-feedback controller. Numerical examples illustrate the effectiveness of the method and the improvement over some existing methods.     

A lagrange approach to set-theoretic control synthesis

A Lagrange approach to solving the nonlinear constrained optimization problem arising in the set-theoretic control problem is described. By introducing matrix Lagrange multipliers, the problem is reduced to that of solving a set of nonlinear simultaneous matrix equations, one of which is the familiar matrix Riccati equation frequently encountered in linear-quadratic control theory. The structural similarities and differences between set-theoretic and linear-quadratic control methods are identified. The results obtained from the set-theoretic control approach are compared with those obtained from the linear-quadratic control approach.     

A numerical method for network operator for synthesis of a control system with uncertain initial values

The problem of synthesis of a control system in which the control is found as a function of coordinates of the state space is considered. It is shown that the solution of the synthesis problem for one given initial state may not provide conservation of the optimal value of the functional under variation of the initial state. A problem of control synthesis is formulated, in which it is necessary to find an optimal control for initial values belonging to a given region. It is proved that if the region of initial values is discrete and contains a finite number of points, then a solution to this synthesis problem exists. To solve the synthesis problem, a constructive computational method is proposed, based on the network operator. An example of solving an applied control synthesis problem is presented.     

Robust observer-based fuzzy control for variable speed wind power system: LMI approach

In this paper, the output-feedback control for stabilizing the uncertain nonlinear system is proposed. For achieving the robust stability, we deal with the parametric uncertainties of the concerned system which is based on the Takagi-Sugeno (T-S) fuzzy model. Also, we derive the observer-based models preserving the property and structure of the uncertainties. The sufficient conditions for output feedback stabilizing controller designs are given in terms of solutions to a set of linear matrix inequalities (LMIs). The simulation results for variable speed wind power (VSWP) system are demonstrated to visualize the feasibility of the proposed method.     

A reward allocation method for reinforcement learning in stabilizing control tasks

Reinforcement learning is an area of machine learning that does not require detailed teaching signals by a human, which is expected to be applied to real robots. In its application to real robots, the learning processes are required to be finished in a short learning period of time. A reinforcement learning method of model-free type has fast convergence speeds in the tasks such as Sutton’s maze problem that aims to reach the target state in a minimum time. However, these methods are difficult to learn task to keep a stable state as long as possible. In this study, we improve the reward allocation method for the stabilizing control tasks. In stabilizing control tasks, we use the Semi-Markov decision process as an environment model. The validity of our method is demonstrated through simulation for stabilizing control of an inverted pendulum.     

A passivity approach to game-theoretic CDMA power control

This paper follows a game-theoretical formulation of the CDMA power control problem and develops new decentralized control algorithms that globally stabilize the desired Nash equilibrium. The novel approach is to exploit the passivity properties of the feedback loop comprising the mobiles and the base station. We first reveal an inherent passivity property in an existing gradient-type algorithm, and prove stability from the Passivity Theorem. We then exploit this passivity property to develop two new designs. In the first design, we extend the base station algorithm with Zames-Falb multipliers which preserve its passivity properties. In the second design, we broaden the mobile power update laws with more general, dynamic, passive controllers. These new designs may be exploited to enhance robustness and performance, as illustrated with a realistic simulation study. We then proceed to show robustness of these algorithms against time-varying channel gains.     

A new computational approach to stability analysis and synthesis of linguistic fuzzy control system

In this paper, stability analysis and synthesis of the type-II (Singleton-type) linguistic fuzzy control system are addressed. First, stability theorems are given for both continuous-time case and discrete-time case and they are recast in the formulation of bilinear matrix inequalities (BMIs). Continuous and discrete iterative linear matrix inequality methods are presented to obtain the feasible solution for the stability conditions represented as the BMI. The interesting feature of this paper is that the suggested method can be applied not only to the stability analysis but also to the controller synthesis. When it is applied to the synthesis of the type-II fuzzy logic controller, the resulting one can theoretically guarantee the stability of the closed-loop system. Finally, the effectiveness of the suggested method is illustrated via computer simulation.     

一电厂热工控制DCS系统设计

以西山孝义金岩公司自备电厂为背景,主要结合循环流化床锅炉机组的运行特点和控制特性,对其热工系统运用集散控制方式进行控制,并采用浙大中控的WebFiled JX-300X系统对单元机组的热工控制系统做了初步的整体设计.     

New approach to robust model reference adaptive control for a class of plants

Motivated by recent advances in designing robust adaptive controllers and in dealing with uncertain dynamical systems, a new model reference adaptive control which is robust to a class of unmodelled dynamics and bounded output disturbances in the case of relative degree one is presented. The implementation of the controllers includes a switching mechanism which plays a crucially important role in functions of stabilizing as well as tracking. It is shown that global stability of the overall system is achieved under no assumption of persistency of excitation, and tracking errors will converge to a residual set whose size can be directly related to the size of unmodelled dynamics and of output disturbances explicitly. In the ideal case, the residual set degenerates to a single null point and convergence can be achieved in finite time without any requirement of persistency of excitation.     

A homotopy approach for nonlinear control synthesis

In this paper, the authors propose a control method for nonlinear systems which relies on the homotopy method for solving nonlinear equations and tangent linearized control systems. They present a mathematically rigorous treatment of the theoretical foundations, including a constructive proof of the exponential error decay for the controlled system which contains an explicit control design instruction. For illustration, this design instruction is applied to an example system. The behavior of the controlled system is examined by numerical simulations. To demonstrate the advantages and drawbacks of the proposed method they include a short comparison with two usual nonlinear control techniques by means of the considered example system