The Inmos transputer has stimulated significant interest in parallel processing for control. It offers real-time implementation of complex algorithms at a reasonable cost but if parallel architectures are to be fully ...
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The Inmos transputer has stimulated significant interest in parallel processing for control. It offers real-time implementation of complex algorithms at a reasonable cost but if parallel architectures are to be fully exploited it is essential that systematic mapping procedures emerge from the application specific solutions presently under consideration. The paper proposes two different mapping procedures. One relies on a fine-grained systolic array description of computation and is applied to transputer realisation of discrete Kalman filters for state feedback control of a simple missile engagement. The other uses an analogue computer flow diagram to produce a real-time simulation of a bank-to-turn missile. In each case practical results have been obtained.< >
The CEGB has devised a distributed computer installation consisting of a host machine and three target machines. One target controls five real and simulated plant systems via a suitable interface. The five plants have...
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The CEGB has devised a distributed computer installation consisting of a host machine and three target machines. One target controls five real and simulated plant systems via a suitable interface. The five plants have been selected to demonstrate different aspects of control such as three-element, cascade and ratio. The plant was designed as scaled down versions of boiler drums, temperature controllers, pressure systems, etc., and has been constructed as working engineeringsystems using hardware such as motors, valves, water tanks and pipework. Each physical plant system may be controlled by a target computer running CUTLASS software schemes. In order to give more of the CEGB trainee engineers hands on experience of real-time control using CUTLASS, the development of a low cost version of the power plant simulator was proposed. The low cost simulator is able to simulate any of the original sections of plant, or several sections simultaneously by using a dedicated microprocessor.< >
The authors believe that there is considerable scope for the exploitation of rule-based control methods in industry and the paper describes their initial attempts at getting to grips with the ideas. The implementation...
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The authors believe that there is considerable scope for the exploitation of rule-based control methods in industry and the paper describes their initial attempts at getting to grips with the ideas. The implementation of rule-based controlalgorithms is considered for two very different types of process. The first involves the use of the 'ball and beam' apparatus which has been studied previously by a number of authors (Wellstead et al. (1978), Rees and White (1984)). The second project deals with the digital control of a marine diesel engine speed. In both cases, the control performance of a linguistic algorithm is compared to more traditional controller designs based on PID, modified deadbeat and state feedback methods.< >
In controlengineering it is now evident that the availability and propagation of computer aided controlsystems design (CACSD) software has had two profound effects: it has helped in the understanding and the teachin...
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In controlengineering it is now evident that the availability and propagation of computer aided controlsystems design (CACSD) software has had two profound effects: it has helped in the understanding and the teaching of the subject, and it has led to the rapid spread of new techniques. The author paints a picture of the hardware and software tools that will become available to control engineers over the next decade, based on what is available today. It is safe to predict that equipment will get faster, cheaper and bigger. It is also safe to predict that the production of CACSD software and its use will get easier and quicker as the software tools are developed. What is distressing however is that the software foundations for these tools were laid ten years ago or more. For example, the popular icon based interfaces of today were conceived as part of the Dynabook project at Xerox, which began in 1960. To take a more exciting (and risky) prediction, look to the development of object oriented hardware to support directly the software concepts that have now been around for a decade and which offer the most hope for the development of software in the future.< >
The applications of two-armed robots is discussed and a review carried out of the main control methods. The teleoperation of robotic systems is then discussed and the need for good operator visualisation coupled with ...
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The applications of two-armed robots is discussed and a review carried out of the main control methods. The teleoperation of robotic systems is then discussed and the need for good operator visualisation coupled with minimum work load was identified as the key to system efficiency. The collision problem is discussed and the method of detecting and avoiding collisions are presented. The authors also identify the need for a real-time collision avoidance system suitable for two co-operating teleoperated arms, and develop a kinematics based modelling scheme which could be used for collision detection and avoidance.< >
A technique for automatically determining the structure of linear discrete-time models from real data is briefly illustrated. For pole-placement control system design, as shown in an example, it is essential that near...
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A technique for automatically determining the structure of linear discrete-time models from real data is briefly illustrated. For pole-placement control system design, as shown in an example, it is essential that near, or exact, pole-zero cancellations should not occur within the model. It has been found that the Young's information criterion (YIC) statistic has consistently identified model structures that are free from such cancellations, and that subsequently result in good control system performance. Naturally, some control system design algorithms, for example predictive controllers, are insensitive to overparameterised models; however the YIC statistic is still useful, as it normally indicates the simplest model structure, which should result in minimum complexity controllers being designed.< >
A process continuously produces data about the state of its variables. Knowledge about the process is embodied in these data. If data representing stable and recovery states are selectively used to induce and refine r...
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A process continuously produces data about the state of its variables. Knowledge about the process is embodied in these data. If data representing stable and recovery states are selectively used to induce and refine rules, these rules will contain the best knowledge of the operators and also knowledge intrinsically contained in the mathematical model of the process control computer. A system is presented which acquires knowledge about an industrial process in the form of rules about how monitored variables can be related to controlled variables to produce stability in dependent variables. The system uses a genetic rule induction algorithm on data specifically selected to contain knowledge about the setting of controlled variables.< >
The variety of methods available to the engineer to control traffic movements in a town or city, includes traffic signal control, which can be implemented as isolated junctions, or in coordinated groups, or over the e...
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The variety of methods available to the engineer to control traffic movements in a town or city, includes traffic signal control, which can be implemented as isolated junctions, or in coordinated groups, or over the entire network, using either vehicle actuated, fixed-time or demand responsive control. It is the 'experts' who, knowing the capabilities and the limitations of the different systems available, establish the correct balance in the application of the various control strategies to a particular town or city. To cater for congestion in an urban network a fourth generation expert system of control is believed necessary. Such a system will be based on automatic incident detection, continuous monitoring of traffic data online, and definition of remedial strategies offline for the implementation of route guidance. The hardware and computer technology exist to make a start on developing an expert system but the data management framework and algorithms to translate the raw occupancy data into effective control strategies using route guidance are not fully researched. The paper presents the results of research which provides some of the foundations for the building of an expert system, and proposes a way forward in achieving a fourth generation of control.< >
A controller for end-effector forces must be powerful enough to handle hybrid position/force controlalgorithms and inverse dynamics, as well as a six axis multi-variable inner-loop controller. It must have the capabi...
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A controller for end-effector forces must be powerful enough to handle hybrid position/force controlalgorithms and inverse dynamics, as well as a six axis multi-variable inner-loop controller. It must have the capability to acquire data from up to twenty-one sensors and output to six actuators. It must allow flexible inter-process communications as well as providing a simple interface between the various levels of control. A fast software development environment is desirable and floating point arithmetic greatly eases data overflow and scaling problems. The author has developed a transputer based real-time controller and measurements show that it should fulfil the computational requirements for force control of an industrial robot. A pipeline architecture has been chosen for data distribution, and show to introduce a negligible delay compared to the sampling period. Reliance on commercially available analogue interface hardware has proved to be a problem, but simple boards can be built to overcome this limitation.< >
The design of continuous-time self-tuning controllers based on the notion of an emulator is introduced. A number of standard algorithms - including model-reference, pole-placement and predictive - are unified within t...
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The design of continuous-time self-tuning controllers based on the notion of an emulator is introduced. A number of standard algorithms - including model-reference, pole-placement and predictive - are unified within this setting and some new algorithms derived. The aim is to place self-tuning control within a conventional controlengineering setting. It is argued that, by basing self-tuning control on controlengineering principles and practice, robust adaptive control schemes will naturally arise. The need to use non-adaptive control weighting to detune the algorithms at high frequency is emphasised.
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