Showing papers on "Open-loop controller published in 2006"

An MPC/hybrid system approach to traction control

Abstract: This paper describes a hybrid model and a model predictive control (MPC) strategy for solving a traction control problem. The problem is tackled in a systematic way from modeling to control synthesis and implementation. The model is described first in the Hybrid Systems Description Language to obtain a mixed-logical dynamical (MLD) hybrid model of the open-loop system. For the resulting MLD model, we design a receding horizon finite-time optimal controller. The resulting optimal controller is converted to its equivalent piecewise affine form by employing multiparametric programming techniques, and finally experimentally tested on a car prototype. Experiments show that good and robust performance is achieved in a limited development time by avoiding the design of ad hoc supervisory and logical constructs usually required by controllers developed according to standard techniques.

Model Predictive Control Design: New Trends and Tools

Abstract: Model-based design is well recognized in industry as a systematic approach to the development, evaluation, and implementation of feedback controllers. Model predictive control (MPC) is a particular branch of model-based design: a dynamical model of the open-loop process is explicitly used to construct an optimization problem aimed at achieving the prescribed system's performance under specified restrictions on input and output variables. The solution of the optimization problem provides the feedback control action, and can be either computed by embedding a numerical solver in the real-time control code, or pre-computed off-line and evaluated through a lookup table of linear feedback gains. This paper reviews the basic ideas of MPC design, from the traditional linear MPC setup based on quadratic programming to more a advanced explicit and hybrid MPC, and highlights available software tools for the design, evaluation, code generation, and deployment of MPC controllers in real-time hardware platforms

Operation and control of a dynamic voltage restorer using transformer coupled H-bridge converters

Abstract: The dynamic voltage restorer (DVR) as a means of series compensation for mitigating the effect of voltage sags has become established as a preferred approach for improving power quality at sensitive load locations. Meanwhile, the cascaded multilevel type of power converter topology has also become a workhorse topology in high power applications. This paper presents the detailed design of a closed loop regulator to maintain the load voltage within acceptable levels in a DVR using transformer coupled H-bridge converters. The paper presents system operation and controller design approaches, verified using computer simulations, and a laboratory scale experimental prototype.

TS-fuzzy-controlled active power filter for load compensation

Abstract: This paper describes the application of Takagi-Sugeno (TS)-type fuzzy logic controller to a three-phase shunt active power filter for the power-quality improvement and reactive power compensation required by a nonlinear load. The advantage of fuzzy logic control is that it does not require a mathematical model of the system. The application of the Mamdani-type fuzzy logic controller to a three-phase shunt active power filter was investigated earlier but it has the limitation of a larger number of fuzzy sets and rules. Therefore, it needs to optimize a large number of coefficients, which increases the complexity of the controller. On the other hand, TS fuzzy controllers are quite general in that they use arbitrary input fuzzy sets, any type of fuzzy logic, and the general defuzzifier. Moreover, the TS fuzzy controller could be designed by using a lower number of rules and classes. Further, in this paper, the hysteresis current control mode of operation is implemented for pulsewidth-modulation switching signal generation. Computer simulation results show that the dynamic behavior of the TS fuzzy controller is better than the conventional proportional-integral (PI) controller and is found to be more robust to changes in load and other system parameters compared to the conventional PI controller.

A Setup for Active Fault Diagnosis

Abstract: A setup for active fault diagnosis (AFD) of parametric faults in dynamic systems is formulated in this note. It is shown that it is possible to use the same setup for both open loop systems, closed-loop systems based on a nominal feedback controller as well as for closed-loop systems based on a reconfigured feedback controller. This will make the proposed AFD approach very useful in connection with fault tolerant control (FTC). The setup will make it possible to let the fault diagnosis part of the fault tolerant controller remain unchanged after a change in the feedback controller. The setup for AFD is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization of all stabilizing feedback controllers and the dual YJBK parameterization. It is shown that the AFD is based directly on the dual YJBK transfer function matrix. This matrix will be named the fault signature matrix when it is used in connection with AFD

Controller design for an induction generator driven by a variable-speed wind turbine

Abstract: This paper presents the modeling, controller design and a steady-state analysis algorithm for a wind-driven induction generator system. An output feedback linear quadratic controller is designed for the static synchronous compensator (STATCOM) and the variable blade pitch in a wind energy conversion system (WECS) in order to reach the voltage and mechanical power control under both grid-connection and islanding conditions. A two-reference-frame model is proposed to decouple the STATCOM real and reactive power control loops for the output feedback controller. To ensure zero steady-state voltage errors for the output feedback controller, the integrals of load bus voltage deviation and dc-capacitor voltage deviation are employed as the additional state variables. Pole-placement technique is used to determine a proper weighting matrix for the linear quadratic controller such that satisfactory damping characteristics can be achieved for the closed-loop system. Effects of various system disturbances on the dynamic performance have been simulated, and the results reveal that the proposed controller is effective in regulating the load voltage and stabilizing the generator rotating speed for the WECS either connected with or disconnected from the power grid. In addition, proper steady-state operating points for an isolated induction generator can be determined by the proposed steady-state analysis algorithm. Constant output frequency control using the derived steady-state characteristics of the isolated induction generator is then demonstrated in this paper

Switching fuzzy controller design based on switching Lyapunov function for a class of nonlinear systems

Abstract: This paper presents a switching fuzzy controller design for a class of nonlinear systems. A switching fuzzy model is employed to represent the dynamics of a nonlinear system. In our previous papers, we proposed the switching fuzzy model and a switching Lyapunov function and derived stability conditions for open-loop systems. In this paper, we design a switching fuzzy controller. We firstly show that switching fuzzy controller design conditions based on the switching Lyapunov function are given in terms of bilinear matrix inequalities, which is difficult to design the controller numerically. Then, we propose a new controller design approach utilizing an augmented system. By introducing the augmented system which consists of the switching fuzzy model and a stable linear system, the controller design conditions based on the switching Lyapunov function are given in terms of linear matrix inequalities (LMIs). Therefore, we can effectively design the switching fuzzy controller via LMI-based approach. A design example illustrates the utility of this approach. Moreover, we show that the approach proposed in this paper is available in the research area of piecewise linear control.

Implementation of Emotional Controller for Interior Permanent Magnet Synchronous Motor Drive

Abstract: This paper presents for the first time the real-time implementation of an emotional controller for interior permanent magnet synchronous motor (IPMSM) drives. The proposed novel controller is called brain emotional learning based intelligent controller (BELBIC). The utilization of BELBIC is based on emotion processing mechanism in brain, and is essentially an action, which is based on sensory inputs and emotional cues. The emotional learning occurs mainly in the amygdala. The amygdala is mathematically modeled, and the BELBIC controller is introduced. This type of controller is insensitive to noise and variance of the parameters. The controller is successfully implemented in real-time using a digital signal processor board ds1102 for a laboratory 1-hp IPMSM. The results show superior control characteristics especially very fast response, simple implementation and robustness with respect to disturbances and manufacturing imperfections. The proposed method enables the designer to shape the response in accordance with the multiple objectives of choices.

Design and real-time implementation of robust FACTS controller for damping inter-area oscillation

Abstract: An application of a normalized H/sub /spl infin// loop-shaping technique for design and simplification of damping controllers in the liner matrix inequalities (LMI) framework is illustrated in this paper. The solution is sought numerically using LMIs with additional pole-placement constraints. This ensures that the time-domain specifications are met besides robust stabilization. The designed control algorithm is implemented using a rapid prototyping controller. The performance of the controller is validated in real time using a detailed model of the power system implemented using Linux PC-based, multi-processor technology. The coupling between the controller and the power system is through a set of DAC and ADC modules in the analogue domain.

A Single Synchronous Frame Hybrid (SSFH) Multifrequency Controller for Power Active Filters

Abstract: Conventional integration-based controllers, such as the multisynchronous PI and the multiresonant controllers, are well adapted for multifrequency-current-control applications. The first controller involves multiple reference frames, while the second one operates in a static frame using multiple resonant regulators. This paper presents a hybrid type of controller, called a single synchronous frame hybrid (SSFH) controller, which combines both features: It operates in an SSF mixing conventional PI and resonant controllers. A detailed design criterion for the SSFH controller is presented based on a frequency-response approach. Digital-implementation aspects (such as computation delays) and the phase margin of the system are taken into consideration during the design process. The SSFH and the multiresonant controllers are compared considering various criteria such as the computational load and the performances in terms of transient and steady-state response. It is concluded that the SSFH controller is a very interesting and execution time-saving structure for heavily distorted multifrequency applications, which is especially adapted for balanced or slightly unbalanced cases

Predictive Control for Dynamic Resource Allocation in Enterprise Data Centers

Abstract: It is challenging to reduce resource over-provisioning for enterprise applications while maintaining service level objectives (SLOs) due to their time-varying and stochastic workloads. In this paper, we study the effect of prediction on dynamic resource allocation to virtualized servers running enterprise applications. We present predictive controllers using three different prediction algorithms based on a standard auto-regressive (AR) model, a combined ANOVA-AR model, as well as a multi-pulse (MP) model. We compare the properties of the predictive controllers with an adaptive integral (I) controller designed in our earlier work on controlling relative utilization of resource containers. The controllers are evaluated in a hypothetical virtual server environment where we use the CPU utilization traces collected on 36 servers in an enterprise data center. Since these traces were collected in an open-loop environment, we use a simple queuing algorithm to simulate the closed-loop CPU usage under dynamic control of CPU allocation. We also study the controllers by emulating the utilization traces on a test bed where a Web server was hosted inside a Xen virtual machine. We compare the results of these controllers from all the servers and find that the MP-based predictive controller performed slightly better statistically than the other two predictive controllers. The ANOVA-AR-based approach is highly sensitive to the existence of periodic patterns in the trace, while the other three methods are not. In addition, all the three predictive schemes performed significantly better when the prediction error was accounted for using a feedback mechanism. The MP-based method also demonstrated an interesting self-learning behavior

TS-fuzzy controlled active power filter for load compensation

Abstract: Summary form only given. The paper describes the application of Takagi-Sugeno (TS) type fuzzy logic controller to three-phase shunt active power filter (APF) for the power quality improvement and reactive power compensation required by a non-linear load. The advantage of fuzzy logic control is that it does not require a mathematical model of the system. The application of Mamdani type fuzzy logic controller to three-phase shunt active power filter have been investigated earlier but it has the limitation of more number of fuzzy sets and rules. Therefore, it needs to optimize large number of coefficients, which increases the complexity of the controller. On the other hand, TS fuzzy controllers are quite general in that they use arbitrary input fuzzy sets, any type of fuzzy logic, and the general defuzzifier. Moreover, TS fuzzy controller could be designed by using less number of rules and classes. Further, in this paper hysteresis current control mode of operation is implemented for PWM switching signal generation. Computer simulation results show that the dynamic behavior of TS fuzzy controller is better than the conventional Pl controller and is found to be more robust to changes in load and other system parameters compared to the conventional Pl controller.

Module and controller operation for industrial control systems

Abstract: A controller and module for an industrial automation system is provided. A logical module employs resources and logic to expose functionality of the module while providing generic interfaces to external components of the module. A controller is operable with the logical module to provide interactions with components that are at, above, or below a layer associated with the controller.

Robust PID control using generalized KYP synthesis: direct open-loop shaping in multiple frequency ranges

Abstract: In this paper, a method for designing PID controllers to meet multiple frequency-domain inequalities (FDI) specifications on the open-loop transfer function in finite and semi-infinite frequency ranges is presented. The method, which is based on the generalized Kalman-Yakubovich-Popov (GKYP) lemma, enables direct loop shaping through LMI optimization without frequency gridding or weights. The resulting synthesis condition is nonconservative; its infeasibility implies that no PID controller exists to meet the specifications. The design method extends to systems with parametric uncertainties using Lyapunov function, which depends on the parameter in a linear fractional manner. The robust PID control design is also reduced to an LMI optimization problem, albeit with potential conservatism. The effectiveness of the GKYP synthesis has been demonstrated through several numerical examples. In addition to PID control design, robust GKYP synthesis applies to open-loop shaping and filtering problems, where the poles of the controller or filter are fixed.

Method and apparatus for a redundancy approach in a processor based controller design

Abstract: A system (20) for handling data of a process with a primary controller (30) and a redundant controller (40). The primary controller (30) includes a primary processor that is operable to perform tracking data tasks by using a low speed bus to cooperate with a tracker controller (32) for storage of tracking data in a tracker memory. The primary processor is further operable to perform other tasks by using a high speed bus in cooperation with a primary memory (32). The second bus (37) has an operating rate considerably higher (for example, a factor of two or more) than that of the first bus (38).

System and method for heat pump oriented zone control

Abstract: A system and method to control environmental parameters of pre-defined zones within an environment using an electronic controller are disclosed. The system includes a non-proprietary electronic controller which enables a weighting value to be assigned to each zone within the environment. The electronic controller also detects any zone service calls from sensor devices associated with each of the zones and determines a cumulative weighting value in response to the detected zone service calls. The electronic controller selects an equipment staging combination from at least two possible equipment staging combinations in response to thermal capacity, and an air handler stage is selected in response to at least the cumulative zone weighting value.

A Parametric Lyapunov Equation Approach to the Design of Low Gain Feedback

Abstract: Low gain feedback has found several applications in constrained control systems, robust control and nonlinear control Low gain feedback refers to a family of stabilizing state feedback gains that are parameterized in a scalar and go to zero as the scalar decreases to zero Such feedback gains can be constructed either by an eigenstructure assignment algorithm or through the solution of a parametric algebraic Riccati equation (ARE) The eigenstructure assignment approach leads to feedback gains in the form of a matrix polynomial in the parameter, while the ARE approach requires the solution of an ARE for each value of the parameter This paper proposes an alternative approach to low gain feedback design based on the solution of a parametric Lyapunov equation Such an approach possesses the advantages of both the eigenstructure assignment approach and the ARE based approach It also avoids the possible numerical stiffness in solving a parametric ARE and the structural decomposition of the open loop system that is required by the eigenstructure assignment approach

Robust stability analysis of voltage and current control for distributed generation systems

Abstract: This paper analyzes the robust stability of a voltage and current control solution for a stand-alone distributed generation (DG) unit using the structured singular value or /spl mu/-framework-based method. The voltage and current control solution consists of a discrete-time sliding mode current controller and a perfect robust servomechanism problem voltage controller, which has been shown effective in transient response and harmonic minimization in previous study without considering parametric uncertainty. The stability robustness of the system and its transient performance are investigated under various tuning parameters of the controller. The analysis results presented in this paper demonstrate that the controller parameters can be tuned and verified to satisfy a certain transient performance requirement and at the same time guarantee robust stability under system parameter uncertainties and load variations.

Miniature surveillance robot

Abstract: A robotic system has a drive chassis having a drive motor and a drive element attached to the first drive motor, Additionally, a motor controller system provides drive signals to the first drive motor. A logic controller provides control signals to the motor controller. A network system is provided for communicating with the logic controller. At least one peripheral element communicates with the network system. There is additionally provided a wireless arrangement for communicating wirelessly with the network system.

An Intelligent Hybrid Fuzzy Pid Controller

Abstract: In this study, a design methodology is introduced that blends the classical PID and the fuzzy controllers in an intelligent way and thus a new intelligent hybrid controller has been achieved. Basically, in this design methodology, the classical PID and fuzzy controller have been combined by a blending mechanism that depends on a certain function of actuating error. Moreover, an intelligent switching scheme is induced on the blending mechanism that makes a decision upon the priority of the two controller parts; namely, the classical PID and the fuzzy constituents. The simulations done on various processes using the new hybrid fuzzy PID controller provides ‘better’ system responses in terms of transient and steady-state performances when compared to the pure classical PID or the pure fuzzy controller applications. The controller parameters are all tuned by the aid of genetic search algorithm.

Intelligent Control of an Autonomous Mobile Robot using Type-2 Fuzzy Logic.

Abstract: We develop a tracking controller for the dynamic model of unicycle mobile robot by integrating a kinematic controller and a torque controller based on Fuzzy Logic Theory. Computer simulations are presented confirming the performance of the tracking controller and its application to different navigation problems.

Adaptive Critic Design Based Neuro-Fuzzy Controller for a Static Compensator in a Multimachine Power System

Abstract: This paper presents a novel nonlinear optimal controller for a static compensator (STATCOM) connected to a power system, using artificial neural networks and fuzzy logic. The action dependent heuristic dynamic programming, a member of the adaptive Critic designs family, is used for the design of the STATCOM neuro-fuzzy controller. This neuro-fuzzy controller provides optimal control based on reinforcement learning and approximate dynamic programming. Using a proportional-integrator approach the proposed controller is capable of dealing with actual rather than deviation signals. The STATCOM is connected to a multimachine power system. Two multimachine systems are considered in this study: a 10-bus system and a 45-bus network (a section of the Brazilian power system). Simulation results are provided to show that the proposed controller outperforms a conventional PI controller in large scale faults as well as small disturbances

Control software updating technique for a network apparatus

Abstract: A network apparatus has first and second controllers that are coupled via communication channel, and is coupled to a network by the first controller. In order to update the firmware of this first controller, the first controller obtains update data for updating via the network and transfers the obtained data to the second controller. The second controller stores the update data transferred from the first controller in a storage device incorporated in the second controller. After the entirety of the update data has been stored in the storage device by the second controller, the second controller transfers the update data to the first controller. The first controller updates the firmware for the first controller using the update data transferred from the second controller.

Design of a fuzzy model predictive power controller for pressurized water reactors

Abstract: In this paper, a fuzzy model predictive control method is applied to design an automatic controller for thermal power control in pressurized water reactors. The future reactor power is predicted by using the fuzzy model identified by a subtractive clustering method of a fast and robust algorithm. The objectives of the proposed fuzzy model predictive controller are to minimize both the difference between the predicted reactor power and the desired one, and the variation of the control rod positions. Also, the objectives are subject to maximum and minimum control rod positions and maximum control rod speed. The genetic algorithm that is useful to accomplish multiple objectives is used to optimize the fuzzy model predictive controller. A three-dimensional nuclear reactor analysis code is used to verify the proposed controller for a nuclear reactor. From results of numerical simulation to check the performance of the proposed controller at the 5%/min ramp increase or decrease of a desired load and its 10% step increase or decrease which are design requirements, it was found that the nuclear power level controlled by the proposed fuzzy model predictive controller could track the desired power level very well.

Method and apparatus to sense and establish operation mode for an hvac control

Abstract: A method for configuring a controller for an HVAC system. The method comprises providing a closed loop refrigerant system and a control system to control the closed loop refrigerant system. The control system comprises a controller, an input device, and a processor including a signal sensing circuit. The input device is activated to provide one or more signals to the controller to control the components of the closed loop refrigerant system. One or more signals are sensed with the signal sensing circuit to determine whether signals are present between the input device and the controller. The signals are processed with the processor to determine what type of closed loop refrigerant system is present. The controller is then configured to control the type of system determined by the processor.