This paper presents details in the implementation of an adaptive autopilot unit used for ship course keeping and course changing. The control strategy is based on the scheme of self-tuning regulator (STR) in which the...
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This paper presents details in the implementation of an adaptive autopilot unit used for ship course keeping and course changing. The control strategy is based on the scheme of self-tuning regulator (STR) in which the generalized minimum variance (GMV) control law is combined with an extended least square (ELS) parameter identification technique. A time-varying extended state Kaiman filter (EKF) is designed to estimate the state of the system under disturbances induced by the sea environment and loading conditions. ELS and EKF constitute an adaptive estimator by which both state vector and parameter vector can be estimated properly. A dual microcomputer system using warm standby redundant design is implemented to guarantee the reliability in the control and safety in the steering. The construction principles of hardware and software are discussed. A sophisticated simulation facility is extensively used in the design stage of the autopilot unit. Several sea trials have been performed at “DAQING 232”, a 15000 tdw tanker, the results of which show that the unit reduces the propulsion losses of the ship motion in addition to keeping the course satisfactorily.
A design frame and a set of circuit elements with which generic motor controllers can be implemented are described. A simple proportional-derivative motor controller was embedded in the design frame. Its performance a...
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A design frame and a set of circuit elements with which generic motor controllers can be implemented are described. A simple proportional-derivative motor controller was embedded in the design frame. Its performance advantages over a more traditional controller are described. Also discussed are the merits of biologically inspired systems used in applications related to robotics.< >
The application of sliding mode control to permanent-magnet synchronous motors (DC brushless motors), wound-rotor synchronous motors, and asynchronous motors is presented. A unified approach to the control problem of ...
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The application of sliding mode control to permanent-magnet synchronous motors (DC brushless motors), wound-rotor synchronous motors, and asynchronous motors is presented. A unified approach to the control problem of AC machines reveals that a simple control algorithm which effectively solves the problem can be derived using variable-structure system theory. Selection of the control variable (angular position, speed, acceleration, or torque) leaves the basic control structure unchanged, and even current limiting can easily be included. The theoretical results are verified by experiments. The design procedure and experimental results show that this approach provides good behavior of the system in both transient and steady-state operation.< >
The interpreting and analysis of real time sampled signals is important for improvement of quality of products. This article developed an expert system shell ASESS for interpreting and analyzing the real time signals ...
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The interpreting and analysis of real time sampled signals is important for improvement of quality of products. This article developed an expert system shell ASESS for interpreting and analyzing the real time signals ...
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The interpreting and analysis of real time sampled signals is important for improvement of quality of products. This article developed an expert system shell ASESS for interpreting and analyzing the real time signals based on the analysis-synthesis (A-S) inference technology which frequently used by human expert in considering complex problems. The A-S technology is introduced. In order to meet the need of speed of real time control, in ASESS two measures are taken: 1. Knowledge classification and meta-rules are applied. 2. The system is developed with the combination of three languages: Assembler, Fortran and Prolog. Considering the vagueness in inference of human experts, the fuzzy inference technology are applied. The knowledge base of ASESS can be separated from inference engine and can be edited easily, so the system ASESS can be used effectively in different cases by adding appropriate knowledge in that field.
In this paper we attempt to propose a method for preference degree analysis in multiobjective decisionmaking problems(MDMPs), called the multiple factor analysis method based on a hierarchical analysis model. The conc...
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In this paper we attempt to propose a method for preference degree analysis in multiobjective decisionmaking problems(MDMPs), called the multiple factor analysis method based on a hierarchical analysis model. The concept of preference degree(PD) is first discussed. Here a PD is used as a measurement for describing preference information of decision makers (DMs) to some value of an objective. A hierarchical model for analyzing the preference information is then deduced by defining objective domain of discourse (ODD), fuzzy degree domain of discourse (FDDD), factor domain of discourse (FDD) and sensitivity vector. Furthermore, some methods are explored for analyzing DMs* PDs of objective values according to a single factor and multiple factors, respectively. At last, an example is briefly introduced.
A general formula for the slope and mathematical models of digitized straight-line segments are derived and discussed in detail. The models are parametric and the parameters are calculated uniquely and in closed form ...
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ISBN:
(纸本)0818608781
A general formula for the slope and mathematical models of digitized straight-line segments are derived and discussed in detail. The models are parametric and the parameters are calculated uniquely and in closed form from the slope without the need for recursion or interaction. The modeling is information-preserving and explicitly uses the slope. The models are in a form convenient for plotting, detecting, and recognizing digitized straight-line segments.< >
An on-line scheme to fault detection in adaptive control systems is proposed by introducing Kullbaek Discrimination Information (KDI) as a detection index. When a physical parameter change due to a failure has occurre...
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An on-line scheme to fault detection in adaptive control systems is proposed by introducing Kullbaek Discrimination Information (KDI) as a detection index. When a physical parameter change due to a failure has occurred in a system under adaptive control, the failure effect will hardly be visible in the output performance because of the adaptation mechanism. Such a parameter change is also difficult to detect by monitoring the regulator parameters, which are determined by a recursive identification based on the direct approach. Since the failure effect is reflected as a change in the predictor model used for the adaptive control design, the fault detection leads to a model discrimination problem. It has been shown that the KDI can be used as an effective distortion measure for the model discrimination and the index can be applied in a modified form to detect a fault on-line. Simulation studies on a second order damped oscillatory system have been carried out to demonstrate the efficiency of the method.
On the basis of self-tuning regulators attention is given to theoretical and practical aspects dealing with the application of adaptive control to ship course keeping. In this papar a LQG optimal controller is develop...
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On the basis of self-tuning regulators attention is given to theoretical and practical aspects dealing with the application of adaptive control to ship course keeping. In this papar a LQG optimal controller is developed which avoids the diffioulty of solving Riccati equation on line. An extended state vector Kalman filter is designed to improve its robustness and convergence. Parameters in both the LQG controller and Kalman filter are estimated by rernrsive least square identification so that the scheme has a high degree of adaptability in the time-variant environment. The control strategies are implemented in a microcamputerized adaptive control unit which has been attached to the autopilot on board “YUHONG” and undergone the sea trials. Results of experiment show that self-tuning regulators reduce the propulsion losses in addition to keeping the course satisfactorily.
The paper presents a demographic-economic simulation model DEM-CEM system. Our efforts at building the DEM-CEM system focus on the construction of an age, sex, region, educational attainment level and skill level spec...
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The paper presents a demographic-economic simulation model DEM-CEM system. Our efforts at building the DEM-CEM system focus on the construction of an age, sex, region, educational attainment level and skill level specified, five dimensional population model—DEM. And integrate the DEM to a Computable general equilibrium model (CGE model) of economic development—CEM. The DEM-CEM system relates population dynamics to economic development of a representative developing country. The simulation's major intended output is illustration of different dynamic path of the economy subject to alternative policy choices. The demographic factor as a policy variable reflects both the quantity and the quality change of the population and labor force over time, and influences the national economic development through channels of the formation of human capital, e.g. formal education system, on-the-job training program, health services etc. Simulations constructed under various historical and policy counterfactual hypotheses, are reported. The results were compatible with much of the earlier literature and certain new results offer a useful foundation for furture quantitative work of policy counterfacutal study.
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