Control Input Energy Research Articles

On the effect of additional input channels on the achievable performance of discrete-time control systems

This paper deals with the quantification of performance bounds in multiple-input multiple-output (MIMO) control systems when energy-constrained input channels are added to the plant. We focus on stable, discrete-time, linear time-invariant (LTI), and right-invertible MIMO systems. The performance is quantified using the 2-norm and assuming step references, whilst the control input energy constraint is on the increments of the additional input signals. Our main result is a closed form expression that quantifies the improvement in performance that results as a consequence of the additional input channels.

Study on Control Input Energy Efficiency of Fractional Order Control Systems

Control input energy efficiency is an important issue which should be considered in designing any control system. Due to the importance of this subject, in the present paper fractional order control systems are studied in the viewpoint of control input energy efficiency. In this study, the divergent terms of the control input energy function of fractional order control systems are obtained. It is shown that these terms have a significant role in the amount of the energy injected to the plant by the controller. Finally, two examples are provided to demonstrate the usefulness of the presented results in the paper.

Optimal Tracking Performance Limitation of Networked Control Systems With Limited Bandwidth and Additive Colored White Gaussian Noise

This paper studies optimal tracking performance issues for multi-input-multi-output linear time-invariant systems under networked control with limited bandwidth and additive colored white Gaussian noise channel. The tracking performance is measured by control input energy and the energy of the error signal between the output of the system and the reference signal with respect to a Brownian motion random process. This paper focuses on two kinds of network parameters, the basic network parameter-bandwidth and the additive colored white Gaussian noise, and studies the tracking performance limitation problem. The best attainable tracking performance is obtained, and the impact of limited bandwidth and additive colored white Gaussian noise of the communication channel on the attainable tracking performance is revealed. It is shown that the optimal tracking performance depends on nonminimum phase zeros, gain at all frequencies and their directions unitary vector of the given plant, as well as the limited bandwidth and additive colored white Gaussian noise of the communication channel. The simulation results are finally given to illustrate the theoretical results.

Study on Adaptive Control of Restrained Cantilever Pipe Conveying Fluid

The cantilever fluid conveying pipe which restrained by linear spring and cubic nonlinear spring at its free end was studied. Firstly, the model reference adaptive control system with parallel structural style was designed for the restrained cantilever pipe based on Lyapunov theory of stability. Then the vibration of the pipe system was under positive controlled making use of this adaptive control scheme. Lastly, the numerical simulating method was used to verify the effectivity of this control method and the influence of system parameters on control performance and control input energy were also investigated. The simulation results showed that the control effect of the control system was extremely distinct. In addition, the larger the Lyapunov function state feedback declinational gains were, the better the control effect had, and the shorter the required time that the controlled system entirely settled down needed. With the position of piezoelectric actuator moved to the pipe free end the required time that the controller entirely settled down would become longer and longer. Moreover, the effect of the length of piezoelectric actuator on the controlled system was relatively complicated, the required time that fluid conveying pipe system settled down and the control energy took on complicated variation regularities.

Minimum entropy based run-to-run control for semiconductor processes with uncertain metrology delay

A novel run-to-run control methodology for semiconductor processes with uncertain metrology delay which is developed by combining the minimum error entropy and the optimal control strategy is presented. In most semiconductor processes, the product quality data from the previous run are not often available before the start of the next run. Thus, the corrective step is often delayed by one batch or more, and the duration of the delay is uncertain with stochastic characteristics. Coupled with inaccurate process models, the delay may lead to significant variations of the process outputs even with the use of exponentially weighted moving average (EWMA) controllers. This paper proposes a new method of handling the uncertain metrology delay from a probability viewpoint. The fundamentals of the run-to-run control systems are first reexamined, and then an innovative performance index is given by incorporating the entropy (or information potential) and the mean value of tracking error with constraints on control input energy. The probability density function (PDF) based optimal control algorithm is proposed for processes where the disturbance and delay are non-Gaussian and the stability of the algorithm is analyzed. In addition, the methodology of the proposed control strategy is extended to include recursive PDF estimation and on-line real time implementation. The paper also includes a simulation example of minimum entropy control of a tungsten chemical-vapor deposition process to illustrate the methodology. Furthermore, comparisons between the conventional EWMA method and the proposed method are done to show the advantages of our newly proposed method.

Fuzzy control with input energy and state variance constraints for perturbed ship steering systems

In this paper, a fuzzy controller design problem is considered for nonlinear perturbed ship steering systems. The nonlinear perturbed ship steering system is transformed into a Takagi-Sugeno (T-S) fuzzy model, which has similar dynamics to the original nonlinear system. By using linear feedback controller design technology, a nonlinear fuzzy controller is developed for the perturbed T-S type ship steering model. Building on the nonlinear fuzzy controller, a number of most important performance constraints in fuzzy control systems are addressed. These include stability conditions, minimum control input energy, and individual state variance constraints. Finally, a numerical simulation is given to show the effects of the proposed fuzzy control methodology.

Continuous Fuzzy Controller Design Subject to Minimizing Control Input Energy with Output Variance Constraints

This paper presents the stability synthesis subject to minimum control input energy and output variance constraints for a class of nonlinear systems, which is modeled by the Takagi–Sugeno (T–S) fuzzy model. For this T–S type fuzzy model, the proposed fuzzy controller design approach not only ensures the stability of the closed-loop system, but also minimizes the control input energy with output variance constraints. The proposed method uses linear matrix inequality technique to find the common positive definite covariance matrix and feedback gains for each rule of the T–S fuzzy models. Finally, the proposed model-based fuzzy control method is used to deal with the control problem of the translational oscillation with a rotational proof mass actuator (TORA) system.

Discussion on: “Continuous Fuzzy Controller Design Subject to Minimizing Control Input Energy with Output Variance Constraints”

Discussion on: “Continuous Fuzzy Controller Design Subject to Minimizing Control Input Energy with Output Variance Constraints”

Robust decentralized control of HVAC systems using [formula omitted]-performance measures

In this paper, we present the results of a study on the use of H ∞ constraints in an optimization technique for the design of robust decentralized output feedback control of a heating, ventilation and air conditioning (HVAC) system. Robust stability and performance specifications are used to achieve temperature control in multi-zone HVAC system in the presence of disturbances and model uncertainties and under constraints on control input energy. The resulting fixed-gain decentralized output feedback controller, which is based on a linear model, is then implemented via simulation on a full bilinear model of the HVAC system. Comparison of these results with those based on “constrained” linear-quadratic optimal regulator design show significantly superior performance of the H ∞ -based design.

Dissipator Placement Design for Truss Structures via Balancing Theory

Application of a balancing theory to the placement of energy dissipators for truss structures is discussed. To apply the balancing theory, theequation of motion for a slightly damped trussstructure is transformed into modal state-spacerepresentation, which is almost invariant under balanced realization. The ratio of future output energy to pass control input energy under state-space representation is chosen as the placement index to design the best placement of energy dissipators. Two types of placement indices are proposed: one is for a e xed initial condition, and the other is for worst-case design, i.e., considering all possible initial conditions. Various cone gurations with different dissipator placements are designed based on the placement indices. Numerical results show that these placement indices can be used as a good design criterion for the placement of linear-friction dissipators for truss structures with a global property.

Actuator and Exciter Placement for Flexible Structures

Systematic approaches to select the optimal candidate sets for actuator and exciter placement are developed. The performance of control and system identiŽ cation for  exible structures depends strongly on the locations of actuators and exciters. The proposed methods of optimal actuator and exciter placement rely on quantitative measures of modal degree of controllability and modal degree of excitability, respectively. Whereas modal degree of controllability is related to the minimum control input energy needed to regulate the system from initial modal disturbances, modal degree of excitability is related to the steady-state energy stored in each mode when white noise is applied to excite the system. The modal degrees of controllability and excitability offer the control system designer tools that allow the ranking of the effectiveness of a speciŽ c distribution of actuators and exciters and, hence, the choice of their locations on a rational basis. The effectiveness of the proposed measures is demonstrated by both computer simulation and an experiment.

Ｙ‐Ｂａ‐Ｃｕ‐Ｏ超電導体を利用した浮上型リニアアクチュエータの基礎研究

Fundamental characteristics of levitation-type linear actuators using Y-Ba-Cu-O high-Tc superconductors are studied theoretically and experimentally. Two types of actuators, both with the levitation using the Meissner effect (Meissner levitation), are studied. They are (1) driven by the force produced by the Meissner effect (Meissner driving), and (2) driven by the Lorentz force (Lorentz driving), respectively. The Meissner levitation has such an advantage that stable levitation is achieved without any control or external input energy except cooling. The magnetic flux distribution and the driving mode of the actuator with the proposed Meissner driving are analyzed numerically. Its operational features are compared with those of several other driving methods, namely, the Lorentz driving and the electrostatic driving. In experiments, the actuator with the Meissner levitation and the Meissner driving is fabricated using Y-Ba-Cu-O superconductors. The levitating force and the driving force are observed to be 200 and 25mgf, respectively. It is found that the magnetic penetration of the superconductors degrades the both forces and the driving of the slider is not succeeded. The actuator with the Meissner levitation and the Lorentz driving is also fabricated. It is found that this actuator has sufficient forces to drive the light slider. The levitating force and the driving force are found to be 10 and 3mgf, respectively. The acceleration of the slider is measured to be 3.5m/s2.