Synthesis Of Feedback Control Systems Research Articles

Approximate methods for H-infinity output feedback control

The problem of finding Hm - regulators in the linear output control problem is considered. Sufficient IT -control conditions for closed loop control law depending on the state vector are formulated. Two approaches for approximate synthesis of the output feedback control systems are proposed. The first is associated with finding a pseudo-solution of the linear model of measuring system as well as with its use in control, the second one - with the synthesis of a state observer generating an estimate of the state vector and its application in control. The step by step algorithm is presented. It is shown that both of suggested methods provide the desired quality of transient processes and asymptotic stability in the model example. The approximate methods could be applied in autopilot design problems for aircrafts and rotorcrafts.

Welcome to 2020 and the Future of Control

Welcome to 2020 and the Future of Control

Variational Analytic Programming for Synthesis of Optimal Control for Flying Robot

The paper presents a novel numerical approach for automatic feedback control system synthesis. The controller is supposed to be described by the control function that depends on objects state. The developed variational analytic programming method allows to construct automatically the mathematical expression of the control function and also to adjust the parameters. The method organizes search of the optimal control function over the set of the small variations of the given basic solution. Search efficiency depends on the quality of the chosen basic solution. An example of automatic control system synthesis for flying robot with state constraints is shown.

Computational Fluid Dynamics Assisted Control System Design With Applications to Central Processing Unit Chip Cooling

In this paper, a computational fluid dynamics (CFD) assisted control system design methodology has been described in detail. The entire design and evaluation procedure has been illustrated through a feedback control system synthesis for a central processing unit (CPU) chip cooling system. The design methodology starts with a full-scale CFD simulation of the nonlinear dynamic process to generate the input and output databases of the process. Using this data set, linear dynamic models around specified operating points are obtained using system identification techniques. Based on these models, one can design appropriate control systems to meet the required closed-loop control system specifications. To illustrate the effectiveness of this technique, it has been used to design a controller for a PC chip cooling system. In particular, the coupling issues between ‘real-time’ dynamic controllers with non real-time CFD simulation have been resolved. A physical experimental test bench based on a cooling system of a Pentium III CPU has been constructed. The feedback linear control systems designed by the proposed CFD approach have been evaluated experimentally for six CPU load conditions.

Characteristic transfer function matrix-based linear feedback control system analysis and synthesis

In this article, the concept of control system synthesis via a method using the characteristic transfer function matrix (CTFM), is explained. Then, the formal definition of CTFM and the associated concept of connectivity are presented. Next, CTFM-based control system analysis and synthesis are discussed, together with the derivation of the necessary and sufficient conditions for the realisation of a proper controller. A summary of the design procedure is presented and three design examples are introduced, in order to illustrate this procedure. Finally, the main conclusions to the work are presented.

Robust Controller Synthesis Based on Circle Criterion-Application to Vibration Control Systems-

It is well-known that stability margins (gain and phase margins) are important quantitative indicators for evaluating stability in feedback control system synthesis. However, when we use conventional techniques based on such stability margins, it may be difficult to suppress the vibration from high-order modes of mechanical system. This paper proposes the robust controller synthesis which achieves both the conventional stability margins and the second phase margin which is a quantitative indicator for suppressing the vibration. The basic idea is to synthesize controller such that the Nyquist locus of open-loop transfer function encircles the immediate outer side of the circle which is specified by the conventional stability margins and the second phase margin. This is formulated as modified H∞ mixed sensitivity problem with the weighting constants which are decided by the center and radius of the circle.

A gradient flow approach to on-line robust pole assignment for synthesizing output feedback control systems

Pole assignment is a basic design method for synthesis of feedback control systems. In this paper, a gradient flow approach is presented for robust pole assignment in synthesizing output feedback control systems. The proposed approach is shown to be capable of synthesizing linear output feedback control systems via on-line robust pole assignment. Convergence of the gradient flow can be guaranteed. Moreover, with appropriate design parameters the gradient flow converges exponentially to an optimal solution to the robust pole assignment problem and the closed-loop control system based on the gradient flow is globally exponentially stable. These desired properties make it possible to apply the proposed approach to slowly time-varying linear control systems. Simulation results are shown to demonstrate the effectiveness and advantages of the proposed approach.

A MULTILAYER RECURRENT NEURAL NETWORK FOR REAL-TIME ROBUST POLE ASSIGNMENT IN SYNTHESIZING OUTPUT FEEDBACK CONTROL SYSTEMS

Pole assignment is a basic design method for synthesis of feedback control systems. In this paper, a multilayer recurrent neural network is presented for robust pole assignment in synthesizing output feedback control systems. The proposed recurrent neural network is composed of three layers and is shown to be capable of synthesizing linear output feedback control systems via robust pole assignment in real time. Convergence of the neural network can be guaranteed. Moreover, with appropriate design parameters the neural network converges exponentially to an optimal solution to the robust pole assignment problem and the closed-loop control system based on the neural network is globally exponentially stable. These desired properties make it possible to apply the proposed recurrent neural network to slowly time-varying linear control systems. Simulation results are shown to demonstrate the effectiveness and advantages of the proposed neural network approach.

A multilayer recurrent neural network for on-line synthesis of minimum-norm linear feedback control systems via pole assignment

A multilayer recurrent neural network is proposed for on-line synthesis of minimum-norm linear feedback control systems through pole assignment. The proposed neural network approach uses a four-layer recurrent neural network for the on-line computation of feedback gain matrices with the minimum Frobenius norm and desired closed-loop poles. The proposed recurrent neural network is shown to be capable of synthesizing minimum-norm linear feedback control systems in real time. The operating characteristics of the recurrent neural network and feedback control systems are demonstrated by use of an illustrative example.

Diophantine equations in control—A survey

This survey is also a tutorial whose aim is to explain the role of diophantine equations in the synthesis of feedback control systems. These are linear equations in a ring and result from a fractional representation of the systems involved. The cornerstone of the exposition is a simple parametrization of all stabilizing controllers for a given plant. One can then choose, in principle, the best controllers for various applications. These ideas evolved from early attempts to use polynomial equations in the design of discrete-time linear systems. By now they have been extended to continuous-time, infinite-dimensional, time-varying and non-linear systems.

Design of a total energy control autopilot using constrained parameter optimization

The application of a multivariable control design method based on constrained parameter optimization to the design of a multiloop aircraft flight control system is described. Specifically, the design method is applied to the direct synthesis of a multivariable inner-loop feedback control system based on total energy control principles. The design procedure offers a structured approach for the determination of a set of controller gains that meet design specifications in closed-loop stability, command tracking performance, disturbance rejection, and limits on control activities. The presented approach may be applied to a broader class of multiloop flight control systems. Direct tradeoffs between many real design goals are rendered systematic by this method following proper formulation of the design objectives and constraints. Performance characteristics of the optimized design have been improved over the current autopilot design on the B737-100 Transport Systems Research Vehicle at the landing approach and cruise conditions, particularly in the areas of closed-loop damping and control activity in the presence of turbulence.

Synthesis of feedback control systems with large plant uncertainty and time-varying gain

A practical design method for feedback systems with large plant uncertainty and time-varying gain is presented. By combining quantitative feedback theory and the circle criterion, the design method assures the stability of the system and improves the performance of the system when the time-varying gain exists.

Vibration control of vehicle using the suboptimal output control with frequency-shaped cost functional.

The theory of linear suboptimal output feedback control with a frequency-shaped cost functional is applied to the vibration control of a vehicle model subjected to the input of the roughness of road surface. The feedback control gain is obtained with respect to a quadratic cost functional whose weighting matrices are functions of frequency. In the control using a frequency-shaped cost functional, the vibration frequency components can be reduced over specific bands of frequencies. Janeway and ISO human response curves with respect to acceleration are used to examine the vibration characteristics of a controlled vehicle model. The theory of the suboptimal control problem subjected to control structure constraints is applied to the synthesis of the output feedback control system. The theoretical and simulated results of the suboptimal output feedback control with a frequency-shaped cost functional are compared with those of the optimal control without a frequency-shaped cost functional and with state estimation using a Kalman filter.

An Optimal output feedback control method and application to a motor‐generator system

AbstractA multi‐input/multi‐output feedback control system synthesis method with output feedback structure is proposed on the basis of an improved optimal regulator theory. The method is applied to a DC motor/AC generator system. The effectiveness of the method is demonstrated by simulation and experimental studies. An input‐output relation is derived through the observable canonical form of the state equations of the controlled object, and an improved optimal regulator theory is applied to the relation. The controller consists of proportional actions, integral actions, difference actions and compensating actions for input delay times. The (l — 1) th‐order difference actions are included in the controller for the controlled object in which an lth‐order output subsystem is included. On the other hand, the (n — 1) th‐order difference actions are included in the previous method for the same controlled object. In order to consider the transient response of the designed control system, the relations between the weighting factors in the defined performance index and the transient response are studied by simulation and experiment. Satisfactory responses for a two‐input/two‐output system are obtained in our experiments.

Efficiency-Optimized Speed Control System with Feed-Forward Compensation

A partial-state and an output feedback control system synthesis method with feed-forward compensation, which doesn't make use of the state observer procedure, are proposed. These are applied to an efficiency-optimized speed control system of a dc motor system. This leads to a decrease in the number of current detectors of the motor system and the channel of the A/D converter. Although they are useful in practice, these control systems are, to some extent, susceptible to noise due to the inclusion of high-order difference actions in the controller. It is inevitable that the transient response becomes slow if the weighting factors in the performance index are chosen so that the influence of noise is decreased. The feed-forward compensation is useful for improvement on the transient response of the control system. But, the feed-forward compensation method for the partial-state or the output feedback control system has not been proposed until now. In this paper, the feed-forward compensation method, which can be applied to all the control systems, is proposed and the effectiveness is examined experimentally. Also, the influence of noise for each control system and the improvement of the efficiency are investigated experimentally.

予見フィードフォワード補償を含む部分状態フィードバック制御系構成法

予見フィードフォワード補償を含む部分状態フィードバック制御系構成法

フィードフォワード補償を含む部分状態フィードバック制御系構成

フィードフォワード補償を含む部分状態フィードバック制御系構成

Output feedback control system synthesis method based on improved optimal regulator theory and its application

A new output feedback control system synthesis method for multiinput and multioutput systems is proposed. The control system consists of difference actions as well as proportional actions, integral actions, and compensating actions for input delay times while only proportional, integral, and compensating actions are included in the full state feedback control system. Simulational and experimental studies for both systems are carried out.

A design method for linear state feedback systems possessing integrity based on a solution of a Riccati-type equation

This paper is concerned with the synthesis of a state feedback control system which possesses both integrity and good responses. System integrity in multivariable control systems is defined as the property that the overall closed-loop system remains asymptotically stable in the presence of a failure in the feedback loop. A state feedback control law which retains asymptotic stability against arbitrary actuator failure is derived using a positive semidefinite solution of a type of matrix quadratic equation, and some properties of the closed-loop system are considered. Moreover, a design procedure by which the closed-loop system has the desired dynamical characteristics while maintaining integrity is proposed, and the effectiveness of the procedure is demonstrated with a numerical example.

Output Feedback Control System Synthesis Method and its Application to Multivariable System

Output Feedback Control System Synthesis Method and its Application to Multivariable System