A new guidance law is developed for governing the flight of hypersonic vehicles. The guidance law is given in analytical form and can effectively track flight path angle and heading angle commands, determining the pro...
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A new guidance law is developed for governing the flight of hypersonic vehicles. The guidance law is given in analytical form and can effectively track flight path angle and heading angle commands, determining the proper angle of attack and bank angle to send to an attitude autopilot. The flight path angle commands can be selected either from experience or using optimization tools in permission planning. The heading angle commands can be determined using waypoint steering.
Two novel and efficient approaches to analyze the stability robustness at the interface between source and loads of a direct current (dc) distributed power system subject to loads that are turned on/off arbitrarily an...
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Two novel and efficient approaches to analyze the stability robustness at the interface between source and loads of a direct current (dc) distributed power system subject to loads that are turned on/off arbitrarily and operating at heavy/light power modes are presented. The first is a rule based algorithm using the Nyquist stability criterion. The second is based on the multivariable stability margin theory. Each of these two approaches provide a different perspective of the dynamic behavior of the system. The first provides classical gain and phase margin. The second addresses the robustness of the system under simultaneous variations in the loadings. Analysis of the stability of the Flight 5A configuration of the International Space Station Electrical Power system (ISS EPS) using the Nyquist criterion is presented.
One significant problem with neural control is that of credit assignment, that is, how should errors in the plant output be used to modify the controller, since the plant is interposed between the controller output an...
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One significant problem with neural control is that of credit assignment, that is, how should errors in the plant output be used to modify the controller, since the plant is interposed between the controller output and the `scored' output. While the controller takes as inputs, the plant outputs, then we can propagate forward the error through the controller network, and then we update its weights. This is the basic principle of the FeedForward Error Propagation (FEP) learning algorithm developed in this paper. This new algorithm does not need a second network (e.g. a critic network or a forward model) to train the controller. This avoid the extra network uncertainty and greatly simplifies the computation complexity and, thus, makes it suitable for on line learning. Here, the FEP algorithm is used to design a direct self-learning controlsystem for the inverted pendulum, and its performance is compared with that of backpropagation based self-learning control.
In the field of vehicle control, conventional cruise controlsystems have been available on the market for many years. During the last years, modern cars include more and more electronic systems. These systems are oft...
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In the field of vehicle control, conventional cruise controlsystems have been available on the market for many years. During the last years, modern cars include more and more electronic systems. These systems are often governed by a computer or a network of computers programmed with powerful software. One of those new services is Adaptive Cruise control (ACC) (or Autonomous Intelligent Cruise control (AICC)), which extends the conventional cruise controlsystem to include automated car following when the preceding car is driving at a lower speed than the desired set-speed. The focus of ACC has mainly been directed towards high-speed highway application, but to improve the comfort to the driver also low-speed situations must be considered. This paper presents an ACC system that is capable of car following in low-speed situations, e.g. in suburban areas, as well as in high-speed situations. The system is implemented in a test car and the result is evaluated.
Model Predictive control technology which evaluates `production costs' is being watched in the field of process-control. Now we have developed the control package for the advanced control of chemical processes, an...
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Model Predictive control technology which evaluates `production costs' is being watched in the field of process-control. Now we have developed the control package for the advanced control of chemical processes, and at the same time we developed an identification tool for making predictive process models. Current tools have problems such as, we can't make high-precision models without efficient identification techniques, and it is not effective for specialized cases of chemical processes. So we developed the identification tool by constructing a GUI and reducing the need for the engineering support by constructing new functions which are for chemical processes cases.
In chemical batch control applications the specification of how to produce a batch is called a recipe. When several recipes execute concurrently within a plant there is a possibility for circular wait between recipes ...
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In chemical batch control applications the specification of how to produce a batch is called a recipe. When several recipes execute concurrently within a plant there is a possibility for circular wait between recipes utilizing shared resources. A circular wait might lead to the loss of an entire batch;this is costly and should therefore be avoided. This work describes the implementation of a discrete-event supervisor aimed to prevent a batch processing system from running into circular waits by restricting resource allocations. The supervisor interacts with SattLine, a commercial controlsystem for flexible production systems, which in turn executes the batch recipes. The supervisor consists of two parts, (1) generation of a circular wait free specification, and (2) an execution part that restricts the behavior of the controlsystem such that the specification is fulfilled.
This paper presents the servo control for an unstable-wheeled system by using disturbance torque observer compensation and a controller designed by convex optimization. We consider that unstable behavior of the mono-w...
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This paper presents the servo control for an unstable-wheeled system by using disturbance torque observer compensation and a controller designed by convex optimization. We consider that unstable behavior of the mono-wheeled system because of one supported point body is caused by the virtual disturbance torque. For this purpose, this paper firstly proposes a design method of disturbance observer in feedback loop for such virtual disturbance torque. In the proposed disturbance observer, ordinary 2nd-order low pass filter for noise attenuation is insufficient to stabilize the whole wheeled system, so a more high order filter is designed by the H∞ loop shaping method from the view point of robust stability. Secondly, the servo controller for the closed loop system including such a disturbance observer is designed by the convex optimization algorithm in order to achieve multiple control specifications simultaneously. The validity of this controlsystem is demonstrated through experiments.
We propose an optimized model of coronary circulation for evaluating patho-physiological hemodynamical changes in the intra myocardial blood flow. The model consisted of an equivalent electrical circuit comprised of e...
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We propose an optimized model of coronary circulation for evaluating patho-physiological hemodynamical changes in the intra myocardial blood flow. The model consisted of an equivalent electrical circuit comprised of epicardial, sub epicardial, the middle layer and the sub endocardial regions. The cost function consisted of squares of the temporal and static changes in perfusion pressures, intra myocardial arterial and venous flow rates and control inputs. We could simulate reported experimental data for coronary arterial and venous flows.
The purpose of this paper is to present a new approach of design of an RST cascaded predictive structure to control rotor position, speed and rotor flux amplitude of an induction machine. The proposed cascaded version...
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The purpose of this paper is to present a new approach of design of an RST cascaded predictive structure to control rotor position, speed and rotor flux amplitude of an induction machine. The proposed cascaded version introduces in the structure of the inner and external loop a new formulation of the reference signals, which enables to track flux and position/speed nominal profiles, satisfying motor constraints. The corresponding cascaded generalized predictive control law with single reference control (CGPC/SRC) is coupled with the nonlinear input-output linearizing control properties. The global control law is also presented with a flux observer and the simulation results obtained in the case of nominal and mismatched parameters on the complete nonlinear model are discussed.
A signal flow graph grammar has been developed that generates signal flow graphs by means of subgraph rewriting. It includes some context-sensitive productions and is very concise. An attribute signal flow graph gramm...
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A signal flow graph grammar has been developed that generates signal flow graphs by means of subgraph rewriting. It includes some context-sensitive productions and is very concise. An attribute signal flow graph grammar has also been formalized as an extended grammar of the signal flow graph grammar, in order to formally define and evaluate a variety of information accompanying signal flow graphs. As a specific example of the attribute signal flow graph grammar, we formalized the attributes and semantic rules to extract the relationships of the signals running in signal flow graphs. A parser-evaluator that we have implemented on the basis of the formalized grammar evaluates the attribute values while it parses a diagram in a bottom-up parallel manner. This attribute signal flow graph grammar is expected to become the theoretical and practical foundation for supporting computerized system analysis and design by using signal flow graphs.
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