This paper presents a new approach to verifying properties of computercontrolsystems with periodic sampling when the control programs include both continuous-variable computations and discrete-state transitions (mod...
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ISBN:
(纸本)078037388X
This paper presents a new approach to verifying properties of computercontrolsystems with periodic sampling when the control programs include both continuous-variable computations and discrete-state transitions (mode switching). We focus on the novel aspects of the approach, which are (1) a formal model for hybrid systems with continuous-time and discretetime behaviors and (2) a method for computing conservative approximations to the sets of reachable states. The formal model and computational routines are incorporated into CheckMate, a MATLAB-based tool for verification of properties of hybrid dynamic systems. This tool is being applied to the verification of embedded controllers in automotive engines.
Explicit piecewise linear state feedback solutions to the constrained linear model predictive control problem has recently been characterized and computed numerically using multiparametric quadratic programming. The p...
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ISBN:
(纸本)078037388X
Explicit piecewise linear state feedback solutions to the constrained linear model predictive control problem has recently been characterized and computed numerically using multiparametric quadratic programming. The piecewise linear state feedback is defined on a polyhedral partitioning of the state space, which may be quite complex. Here we suggest an approximate multi-parametric quadratic programming approach, which has the advantages that the partition is structured as a binary search tree. This leads to real-time computation of the piecewise linear state feedback with a computational complexity that is logarithmic with respect to the number of regions in the partition. The algorithm is based on heuristic rules that are used to partition the state space and estimate the approximation error.
Modem aircraft include a variety of automatic controlsystems that aid the flight in navigation, flight management, and augmenting the stability characteristics of the airplane. Typical controlsystems development inv...
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ISBN:
(纸本)078037388X
Modem aircraft include a variety of automatic controlsystems that aid the flight in navigation, flight management, and augmenting the stability characteristics of the airplane. Typical controlsystems development involves multiple requirements or objectives. On the other hand, the increasing level of complexity and sophistication of aircraft systems leads to a hierarchical architecture that the overall system consists of many distributed components and subsystems. It brings a even more challenging task to consider the multi-objective design and integrated control together. Previous work has been conducted to propose a uniform framework and design approach where control integration strategy and multiple objectives can be addressed simultaneously, however, the complexity of designed controller may not lead to a practically sound solution. In this paper, we present the investigation of reducing the order of the controller using the model reduction techniques. A numerical pitch/speed autopilot is further applied to illustrate the effectiveness of controller order reduction.
This paper discusses three different multiobjective control schemes, which are multiobjective PID control, multiobjective critical control and multiobjective eigen-structure assignment. The multiobjective PID control ...
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ISBN:
(纸本)078037388X
This paper discusses three different multiobjective control schemes, which are multiobjective PID control, multiobjective critical control and multiobjective eigen-structure assignment. The multiobjective PID control considers a set of frequency-domain performance requirements, such as gain margin, phase margin, crossover frequency and steady-state error. The multiobjective critical control addresses the robust controldesign of multivariable critical systems with external and internal uncertainties. The design problem formulated as a set of objectives includes the output performance criteria in the time domain and the robust performance criterion in the frequency domain. The multiobjective eigenstructure assignment studies robust eigenstructure assignment with multiobjective criteria for multivariable controlsystems. Various performance functions in the objectives that are taken into account are individual eigenvalue sensitivity functions and the system robustness functions. Based on those above performance functions, the performance criteria for each multiobjective scheme are expressed by a set of inequalities. The paper introduces various optimisation techniques to make full use of the freedom provided by PID, critical control and eigenstructure assignment to formulate the controller design of satisfying the system performance criteria.
The aim of this project is to exploit artificial intelligence research outcomes to provide a multifaceted support for users of modeling and simulation techniques, reducing thus the time required to learn the technique...
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This paper describes a tool to aid in the analysis and design of combined sewer networks. Complex drainage systems include actuators, like flow-diversion gates and detention tanks, which should be optimally controlled...
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ISBN:
(纸本)078037388X
This paper describes a tool to aid in the analysis and design of combined sewer networks. Complex drainage systems include actuators, like flow-diversion gates and detention tanks, which should be optimally controlled in order to minimize flooding and combined sewer overflow (CSO), through these optimisations volume to waste water treatment plants (WWTP) is maximised. CORAL is a tool able to model a combined sewer network, simulate rain events, calculate actuators optimal policies reproduce past rain events and calculate different balances for all model elements.
The performance requirements stated in project specifications often comprise conflicting objectives. These objectives may further be a complex mix of steady state and dynamic performance. control devices such as solen...
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ISBN:
(纸本)078037388X
The performance requirements stated in project specifications often comprise conflicting objectives. These objectives may further be a complex mix of steady state and dynamic performance. control devices such as solenoid actuators are often chosen purely on steady state force characteristics, due to the difficulty of appraising the conflicting and generally non-linear nature of the performance objectives. This can have ramifications in terms not only of the actuator performance, but also in the overall controllability of the system when closed-loop control is implemented. An example automotive application examining the multi objective controllability of electronically actuated valves is presented. Multi Objective Evolutionary techniques are utilised to derive the optimal force-displacement characteristics and also dynamic characteristics of the desired actuator under the constraint of design performance criteria. The selected actuator is then assessed for its controllability and dynamic performance.
Multi-objective optimisation is a proven, well-known parameter tuning technique in controldesign. It is especially suited to solve complex, multi-disciplinary design problems. This paper describes a software environm...
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ISBN:
(纸本)078037388X
Multi-objective optimisation is a proven, well-known parameter tuning technique in controldesign. It is especially suited to solve complex, multi-disciplinary design problems. This paper describes a software environment, called MOPS (Multi-Objective Parameter Synthesis), which supports the control engineer in setting up his design problem as a properly formulated multi-objective optimisation task. To this end, MOPS offers a basic controlsystem criteria library, a generic multi-model structure for multi-disciplinary problems and a generic multi-case structure for robust control law design, as well as visualisation tools for monitoring the design progress. Several additional features for dealing with a large amount of parameters and criteria, distributed computation for time consuming computations and the use of external simulation and analysis servers are also provided. MOPS also supports parameter estimation in identification problems and optimisation based design assessment for robustness. The user is provided with a clear application program interface and a graphical user interface bo implemented in MATLAB. To solve the underlying optimisation problem different powerful optimisation procedures are available.
In this paper, we propose a new algorithmic solution for the simultaneous stabilisation by decentralised static output feedback problem. The addressed problem is considered in its equivalent formulation as a feasibili...
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ISBN:
(纸本)078037388X
In this paper, we propose a new algorithmic solution for the simultaneous stabilisation by decentralised static output feedback problem. The addressed problem is considered in its equivalent formulation as a feasibility one involving Bilinear Matrix Inequalities (BMI, for short), which is well known to be very hard to solve. The procedure we describe generates solutions to the original problem by solving a sequence of auxiliary quadratic problem where each one of which is solved by standard methods. As our numerical procedure tends to place some eigenvalues near to the jomega - axis, we have included an additional constraint related to pole placement in order to avoid this identified undesirable feature. At the end, some potentialities of our scheme are illustrated through two numerical examples.
In this paper we used the Linear Fractional Representation (LFR) toolbox for the numeric generation of an LFT model. The LFT model was used for structural aircraft analysis in order to determine the onset of flutter. ...
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ISBN:
(纸本)078037388X
In this paper we used the Linear Fractional Representation (LFR) toolbox for the numeric generation of an LFT model. The LFT model was used for structural aircraft analysis in order to determine the onset of flutter. The equation of motion for structural aircraft response is first parametrised in terms of Mach number to obtain matched flutter solutions. From this parametrisation, LFT models for flutter analysis were analytically and numerically generated. The flutter analysis results of the LFT models is compared with flight test results. Finally, an LFT model is generated with perturbations in Mach number, mass, damping and stiffness for robust flutter analysis. The results from this analysis are compared with flight test data and correlate better than unperturbed nominal model analysis.
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