A canard-controlled missile airframe configuration with a twist-and-steer (or polar) control system affords economies in design and kinematic performance but at present does not permit a direct analytical solution for...
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A canard-controlled missile airframe configuration with a twist-and-steer (or polar) control system affords economies in design and kinematic performance but at present does not permit a direct analytical solution for the optimum guidance and roll control autopilot laws. The development of a stable roll loop of adequate bandwidth and response is fundamental in a twist-and-steer missile. Whilst the application of modern control theory has been successfully applied to the design of aileron-constrained time-invariant cases, its extension to the nonlinear case requires further development. Roll loop design is commonly carried out using frequency-domain methods coupled with detailed mathematical modelling and digital simulation. The use of commercially available control system design programs facilitates loop design and sensitivity studies across the operating envelope. Describing function techniques may be used to investigate limit cycle stability etc. The paper discusses the aerodynamics and the computer-aided design.< >
Developing software to control safety-critical applications requires programming abstractions that are unavailable in many of today's programming languages. The Ada programming language was designed to provide sup...
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Developing software to control safety-critical applications requires programming abstractions that are unavailable in many of today's programming languages. The Ada programming language was designed to provide support for such applications within a unified language framework, but it is now commonly accepted that the language has not totally succeeded in achieving all its stated design goals. Ada has successfully addressed many of the software engineering issues associated with the production of large real-time software. It has failed, however, to satisfy applications requiring the use of multiple computers or parallel-intensive computation. Ada is under review. The goal of the revision activity, designated the Ada 9X project, is to provide essential language requirements with minimum negative impact and maximum positive impact on the Ada community. The paper reviews the emerging distribution requirements for Ada 9X.< >
The three principal military high speed data bus standards are Draft Proposal STANAG 3910, SAE AS 4074.1 Linear Token Passing Bus and AS 4074.2 High Speed Ring Bus. There is a significant difference between 3910 and t...
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The three principal military high speed data bus standards are Draft Proposal STANAG 3910, SAE AS 4074.1 Linear Token Passing Bus and AS 4074.2 High Speed Ring Bus. There is a significant difference between 3910 and the SAE standards, in that 3910 makes use of the existing STANAG 3838 (Mil Std. 1553B) to control access to a high speed (20 Mbit/sec) channel. In meeting the needs of time critical systems the only difference between 3910 and 1553B is the message length that can be transmitted within the latency bounds of 1553B. Nevertheless, 3910 has a number of significant advantages for near term and retro-fit applications. In particular, the tried and tested practice of co-siting the data communications control function with the controlling system element can be retained; the way in which communications and systems control is to be achieved with truly general purpose high speed data buses such as those produced by SAE is yet to be resolved.< >
This paper describes a case study in which an assembly planning problem is distributed across a computer network. A distributed robot arm planning system (RAPS) is used to define a solution to the blocks world problem...
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This paper describes a case study in which an assembly planning problem is distributed across a computer network. A distributed robot arm planning system (RAPS) is used to define a solution to the blocks world problem. This problem is concerned with the formation of a plan to enable a robot arm to manipulate arrangements of equally sized cubes situated on a flat table. The simulation work is based on this problem. The paper presents results on two key issues that are relevant to designers of distributed planning systems, namely cooperation frameworks and the efficient exploitation of distributed hardware. Because the components of a distributed planning system rarely have sufficient information or ability to solve the problem as a whole uniquely, the issue of cooperation arises. R.G. Smith and D. Randall (1981) identify two methods of cooperation, the result sharing and the task sharing frameworks. The result-sharing framework describes the cooperation of independent planning components through the communication of partial results. Integration and convergence are achieved by each component's attempt to maintain an internal state consistent with its environment. The demonstration software that implements this framework is coded in the Occam concurrent programming language and is targeted at a network of transputers. RAPS is evaluated using simulation tools.< >
The article describes a multi-level modelling system, MODEL, developed for compartmental modelling of physiological systems. MODEL provides a unified framework for both qualitative and quantitative simulations of beha...
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The article describes a multi-level modelling system, MODEL, developed for compartmental modelling of physiological systems. MODEL provides a unified framework for both qualitative and quantitative simulations of behaviour based on an explicit conceptual representation of the system of interest. The main applications are to problems in metabolism, and to drug kinetics and effects. The authors report the state of development of a multi-level model for glucose-insulin interaction in diabetes.< >
Self-tuning control has been a field of vigorous research interest for many years now and has been accompanied by a plethora of short term applications. In order to extend the period of application of self-tuning cont...
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Self-tuning control has been a field of vigorous research interest for many years now and has been accompanied by a plethora of short term applications. In order to extend the period of application of self-tuning controllers and to establish them as an industrially viable alternative it is necessary to prove their advantage over the resident control system. So often in the past the motivation for application of self-tuning control has not been as a result of a study of the process and its problems, but more of a half-hearted stab at obtaining practical results. This paper attempts to re-state self-tuning controllers as tools which the control engineer will find useful for appropriate long term applications.
This conference proceedings contains 11 papers. The main subjects are unconstrained and constrained optimization methods, integrated system optimization and parameter optimization, optimization of project control usin...
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This conference proceedings contains 11 papers. The main subjects are unconstrained and constrained optimization methods, integrated system optimization and parameter optimization, optimization of project control using heuristic techniques, optimal satellite trajectories, optimal engine performance, and water system optimization.
The author is a member of the Performance Engineering division within British Telecom and the division undertakes performance evaluation on new equipment and services being introduced into BT's network. The author...
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The author is a member of the Performance Engineering division within British Telecom and the division undertakes performance evaluation on new equipment and services being introduced into BT's network. The author's lecture concerns one example of such studies. An important feature of the new equipment is the use of processors to perform realtime control of the equipment and the services provided by the equipment. A control processor typically consists of a number of CPUs, a main memory and a secondary store, all being interconnected by databuses. In its real-time control environment, the processor must have an adequate rate of data transfer between its main memory and secondary store. This is the specific topic of the author's lecture.
The problem of the evaluation of the stability of a nonlinear system can often be converted to one of determining whether limit cycles can exist. Methods for the determination of limit cycles are therefore particularl...
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The problem of the evaluation of the stability of a nonlinear system can often be converted to one of determining whether limit cycles can exist. Methods for the determination of limit cycles are therefore particularly important especially when the available absolute stability methods for nonlinear systems have many limitations. These procedures, which are based on the describing function (DF) or Tsypkin's method, have been incorporated in a set of software programs known as SUNS, Sussex University Nonlinear Software. The aim of this brief review is to outline the pertinent features of the software and to illustrate some of itsapplications for limit cycle determination.
This paper deals with the application of optimal control techniques to improve the boiler efficiency of fossil-fired power stations, by better control of the combustion air flow. This improvement has been made possibl...
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This paper deals with the application of optimal control techniques to improve the boiler efficiency of fossil-fired power stations, by better control of the combustion air flow. This improvement has been made possible by the availability of improved flue gas analysis instrumentation and the use of distributed digital control on power stations. This technique was pioneered in 1974 at Aberthaw A, an oil-fired power station, and, later, installed at Pembroke, a much larger oil-fired station. More recently it has been used at Didcot, a large coal-fired power station.
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