Transactions of the Institute of Measurement and Control

Linkens, D.A.; Rimmer, S.J.; van den Bosch, P.P.J.

doi: 10.1177/014233128400600201pmid: N/A

muPSI is a block-oriented, continuous system, simulation language implemented on a microcomputer with a Z80 processor, 56K RAM and twin floppy discs. It retains all the facilities of its minicomputer parent language PSI, together with additional features for implementation of computer control schemes, Intermachine communication is feasible via analogue channels and also provides for real-time clock facilities and hand-shake protocol for machine synchronisation. A version is also available which allows for multiprocessor communication via serial RS232 digital linkage. The use of muPSI is illustrated via a stand-alone benchmark problem involving the cardio-vascular system, and a self-tuning computer control example involving naval frigate manoeuvring. The language offers extensive simulation facilities using a desk-top microcomputer system, and should be useful as an educational tool as well as in research and development projects.

Kocache, R.M.A.

doi: 10.1177/014233128400600202pmid: N/A

The paper traces the origins of the relevant developments that have led to the emergence and contributed to the evolution of the solid-electrolyte oxygen sensor. Its main features are discussed in general, and a number of different sensor designs are then critically examined.

Riordan, D.C.; Thompson, S.

doi: 10.1177/014233128400600203pmid: N/A

Smith, A.J.

doi: 10.1177/014233128400600204pmid: N/A

This note describes a simple method for solving distributed heat exchanger models while preserving their distributed nature. The method is illustrated for the case of parallel flow exchangers, and a comparison of analytic and numerical results is given for a simplified case.

Buchanan, G.; Whittington, H.W.

doi: 10.1177/014233128400600205pmid: N/A

The feasibility of large, unmanned, offshore wind and wave energy convertors will be greatly enhanced by the availability of highly reliable electronic systems to provide on-board control and condition monitoring systems. However, there is a danger that the extreme environmental conditions found offshore will adversely affect the reliability of electronic systems.This paper quantifies the reduction in reliability to be expected due to the offshore environment and also compares the environmental effect with all other known factors which can reduce the reliability of electronic components and systems.It is concluded that, important as the environmental factor is, its effect can be swamped by other factors such as equipment temperature and packaging technique. The design of reliable electronic systems for use offshore is possible without incurring military-type costs by following a few basic design rules. Ideally, offshore systems should be designed from the component level up, following these rules, rather than by simply sealing 'onshore systems' in watertight boxes.

Mottram, R.C.; Mohammad, W.A.

doi: 10.1177/014233128400600206pmid: N/A

The accuracy of most flowmeters is seriously affected by pulsations, and these must be damped before reliable measurements can be achieved. Damping criteria based on the Hodgson Number have been used for many years in flow measurements made with differential pressure-type flow meters. The objects of this paper are to demonstrate the validity of such criteria in gas flows and to specify their frequency limits.A damping criterion derived from a theoretical analysis applicable to any pulsation waveform is presented. Results of experimental tests carried out with both piston- and siren-type devices, producing pulsations of sinusoidal and non-sinusoidal waveforms in the frequency range of 5-500 Hz, are shown. The results verify that the damping criterion is valid on the Surrey University air flow rig at various pulsation amplitudes and damping volumes at frequencies below 50 Hz.It is suggested that these results are applicable to any gas flow system provided the limiting frequency is such that:(i) The dimensions of the damping chamber are not greater than one-tenth of the pulsation wavelength.(ii) The length of pipe between damping tank and flowmeter should not exceed one-fifth of the pulsation wavelength.

Landers, P.

doi: 10.1177/014233128400600207pmid: N/A

Complementary filtering theory is used to explain the behaviour of three mammalian reflexes, all concerned with the measurement of head angular movement and with reflex control of eye movements. A short explanation of complementary filtering theory is followed by a discussion of the vestibulo-ocular reflex. Experimental results are presented, indicating the frequency response of this system and a transfer function is derived. The optokinetic reflex is then described, and results of further experiments are used to obtain a transfer function for these two reflexes combined. A transfer function is then obtained for the optokinetic reflex alone. This is compared with that obtained for the vestibulo-ocular reflex, and the two are found to be consistent with complementary filtering theory. This theory is then used to predict the dynamics of the cervico-ocular reflex, and these predictions are compared with the experimental results of others. Complementary filtering theory is found to conform well with all the experimental results described, and it is therefore claimed that the three reflexes combined may be regarded as a complementary filter.