School of Aerospace, Transport and Manufacturing (SATM)

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Open Access
The influence of air and liquid properties on airblast atomization
(Cranfield University, 1974-09-01) Rizkalla, A. A.; Lefebvre, A. H.
This thesis reports the results of a detailed programme of research on airblast atomization carried out using a specially designed atomizer in which the liquid is first spread into a thin sheet and then exposed on both sides to high velocity air. The primary aim of the investigation was to examine the influence of air and liquid properties on atomization quality. The work was divided into four main phases:- (1) The first phase was confined to the effects of liquid properties, namely viscosity, surface tension and density on mean drop size. Special liquids were produced to study the separate effect of each property on atomization quality. They presented a range of values of viscosity from 1.0 to 124 centipoise, while surface tension and density were varied between 26 and 73.5 dynes/cm and 0.8 and 1.8 gm/cm3 respectively. Atomizing air velocities covered the range of practical interest to the designers of continuous combustion systems and varied between 60 and 125 m/sec.(2) To obtain experimental data on the influence of air properties, notably air density, on mean drop size, the air temperature was varied between 23 and 151°C at atmospheric pressure in one series of experiments, while a separate study on the effect of air pressure on atomization quality was undertaken, where tests were conducted at constant levels of air velocity and temperature, using a range of liquid flows from 5 to 30 gm/sec, at various levels of air pressure between 1 and 8.5 atm. (3) In order to provide a comprehensive picture of airb1ast atomizer performance over a wide range of conditions the separate effects of varying air velocity, liquid flow rate, and hence atomizing air/liquid mass ratio on SMD were examined. This study enabled a better understanding of the effects of changes in operation on the atomizer's performance. (4) In all three phases above, velotities of both inner and outer atomizing air streams were kept equal. This last phase was aimed at studying the effect of varying the velocity between the inner and outer air streams. Best atomization quality was achieved when 65% of the total atomizing air was flowing through the outer stream. A detailed description of the light-scattering technique for drop size measurement is included. A discussion on the importance of the results obtained and their direct relevance to the design of airblast atomizers is given. A dimensional analysis and inspection of all the data obtained on the effects of air and liquid properties on atomization quality showed that over the following range of conditions: Liquid viscosity 1.0 to 44 centipoise Liquid surface tension 26 to 73.5 dynes/cm Liquid density 0.78 to 1.5 gm/cm³ Air velocity 70 to 125 m/sec Air temperature 20 to 151 °c Air pressure 1.0 to 8.5 kgf/cm² . Air/liquid ratio 2 to 6 Cont..........
Open Access
The design development and evaluation of an active control aircraft model wind tunnel facility.
(1982-09) Malik, I.A.; Cook, M. V.
Recent progress in the field of Active Controls Technology(ACT) has resulted in increased interest in dynamic wind tunnel testing for basic research. The present work reports the findings of a three year research and development programme to build a dynamic wind tunnel testing facility. The task included the design and construction of a controllable dynamically scaled aircraft model, a suspension system to give the model four degrees of freedom, and an electronic control unit to interface with the model for operating the primary controls, for stability augmentation and for providing output signals for measurement purposes. The dynamic characteristics of the model have been recorded for some simulated representative flight conditions and are compared with theoretical predictions and the expected characteristics derived from full size aircraft data. The use of various stability augmentation functions has also been investigated to assess the usefulness of the electronic control unit as a means for providing stability augmentation. The results show the system to have considerable potential as an ACT Simulator. Modifications are suggested for further development of the facility to achieve a higher degree of accuracy and versatility.
Open Access
Theory and practice of a horizontal-axis flexible sail type wind-turbine behaviour.
(1988) Arithoppah, Sateeam; Probert, S. D.
A sail of 0.3m x 0.28m, with 1% slack, was placed in the test section of a wind tunnel. Both surface visualization and pressure distribution tests were undertaken with the sail at various angles of attack, oc , relative to the wind, for a constant wind speed of 5 m/s. As O the angle of incidence was increased from 2.5 , it was found that the flow round the sail behaved in a smooth manner until oc reached 15° . Beyond 15° , flow separation became dominant and for higher angles of attack (i.e. oc >25°) the sail flapped violently. It was also found that the lift increased linearly with oc and the sail stalled at an angle of incidence of oc =15° . At zero angle of attack the lift was found to be negative. The performance of a fully-augmented flexible sail-type wind turbine has been investigated. The augmentation devices (i.e. centre-body and tip-fins) used resulted in an increase of about 60% over the unaugmented wind turbine. Tests were carried out so as to determine the pumping characteristics of the wind turbine when it was coupled to a commercially-available peristaltic pump. Aerodynamic characteristics of the interacting sails, together with the effectivenesses of the above mentioned augmenting devices, were investigated using a flow-visualization technique and this was done at the optimal operating wind-speed of 5 m/s. Tests on the wind-turbine/pump combination show that the cut-in and cut-out wind speeds for the pump to function were 3.71 and 11 m/s respectively.
Open Access
Fluid flow and heat transfer around mechanical seals.
(1990) Barnes, N. D.; Sanderson, M. L.
Mechanical seals are used extensively on rotary applications where the sealed fluid is under pressure. They may rightly be considered to be generally reliable and trouble free, many giving lives of over 3 years. However, a significant number, particularly on arduous and often critical duties, exhibit apparently random mid-life failure characteristics which cannot be easily explained. Of these "random" failures, the largest proportion appear to be attributable to overheating due to loss of the vital interface fluid film. The mechanism of interface film loss depends on a large number of interrelated variables and a substantial amount of work has been carried out over many years to attempt to alleviate the problem. Little work however has been reported on the nature of the fluid flow around the seal; this is determined by seal chamber geometry and affects the removal of potentially deleterious heat, vapour or gases, and solids. At present, many seals are required to run in "stuffing boxes" - cavities designed for soft packing rather than mechanical seals. The aim of this project has been to study the flow behaviour in these stuffing boxes and a number of novel chamber designs. The techniques involved using transparent housings and direct measurements of convective heat transfer coefficients. Significant improvements over existing designs were achieved using a housing flared at 45° away from the seal and this design forms the basis of recommendations for improved seal systems. This design was tested under simulated field conditions described in a Design Study and Case Study and found to be successful. The recommendations are backed up by a mathematical model of turbulence viscosity which seeks to explain some of the complex structured flows observed. A corollary to the thesis explains how the results of this work will form a major input to improved international standards.
Open Access
Efficient fracture mechanics programming system for linear and non-linear problems using finite-element and boundary-element methods
(1990-06) Al-Edani, Ameen Ahmed Nassar; El-Zafrany, A. M.
An attempt has been made, in this work, to design an efficient, linear—elastic and elasto-plastic, fracture mechanics package based upon finite and boundary element methods. The package contains many useful facilities such as, pre- and post-processors, different types of loading including inertial and thermal loading, and different types of finite and boundary elements. New crack-tip elements, and efficient algorithms for the analysis of J-integrals, have been derived. Elasto-plastic boundary element programs with different types of loading, and using a new subregion facility have also been developed. The package was employed for fracture mechanics analysis of some case studies with elastic, thermo-elastic, and elasto-plastic conditions, and with one and two modes of fracture. The results have proved that the package is very reliable and controllable, and new facilities and techniques, developed in this work, can provide useful tools for fracture mechanics analysis.
Open Access
Fluid driven rotary atomiser for controlled droplet application of herbicides.
(1991-04) Craig, I. P. S.; Parkin, C. S.
Handheld electrically driven spinning disc atomisers are capable of applying pesticides more efficiently than with hydraulic nozzles, because the narrower droplet spectra they produce leads to reduced drift and wastage of chemical. Despite these savings however, farmers are frequently reluctant to use such methods because of poor reliability, and high maintenance costs of the electrical drive systems. This research has therefore examined an alternative drive system using a jet of the pesticide fluid to power the atomiser. Experiments have been carried out to increase understanding of the processes involved, with the aim of producing an optimum design suitable for mounting to a knapsack sprayer. The fluid drive mechanism is comparable to that of a Pelton Wheel; driving torque arises from a change in momentum of a fluid jet as it strikes the inside of a cup causing it to rotate. The fluid is emitted from grooves and teeth to form ligaments which produce uniform droplets. Peripheral distribution of fluid is made uniform by a series of slotted weirs on the inside wall of the cup. Form and size of various components including the nozzle, bearing, cup and atomising disc have been investigated. The requirement for low flowrate necessitates the use of a small nozzle with filter. Supply pressure available from hand- pressurised knapsack sprayers is also restricted. Available input energy is therefore limited, requiring that all the processes leading up to atomisation are as efficient as possible. Rotational speed is a function of jet velocity, mass flowrate, inner and outer cup radius, and bearing frictional torque. A simple computer model has been developed to predict the effects of changing these parameters. Radial exit velocity of the fluid has been derived from a consideration of the viscous forces to which thin fluid layers are subject during centrifugal acceleration upon rotating surfaces. This has enabled undisturbed ligament radius to be calculated, and has therefore provided a satisfactory method for the prediction of dropsize. Spectral and deposit characteristics are satisfactory for CDA herbicide application with water based formulations, although antifoam agent is required for formulations containing surfactant. Typical average droplet size for an operating pressure of 3 bar is 250μm, and optimum swath width is 1.2m for an intended application rate of 30 to 40 litres per hectare.
Open Access
Natural co-ordinates and high speed flows, a numerical method for reactive gases
(1992) Dawes, A. S.; Clarke, J. F.
A new high resolution, space marching, numerical method, based on operator splitting, for high speed, steady, planar two dimensional, Inviscid, chemically reacting (real gas) flow fields as described. A simple model for chemical non-equilibrium was used based on Lighthill's ideal dissociating gas model for diatomic Oxygen. The method is formulated within the natural co-ordinate space consisting of streamlines and their normals. Boundaries are treated exactly and the variation of the chemistry shown to be along the streamline co-ordinate. Operator splitting is used to split the full problem up into two consisting of the wave and chemical contributions. We use the Riemann problem based Random Choice Method (RCM) for solving the homogeneous Euler equations with frozen initial data for the wave contribution. The definition of the Riemann problem for the natural co-ordinate space is described. The RCM does not suffer from numerical smearing or spurious oscillations like other methods and this will be a positive advantage for chemical non-equilibrium due to the sudden rise in temperature across a shock wave. The flow field changes due to the chemical non-equilibrium are included by solving numerically a system of stiff ordinary differential equations. This was done using the stiff solver LSODE. The algorithm is first validated for inert flow fields. This is done by making comparisons between theoretical and experimental results for several classic high speed configurations. The method is then validated for chemical non-equilibrium by making comparisons with results from other numerical methods. Finally, the qualitative effect of these real gas effects on the aerodynamic characteristics of s simple re-entry profile (modelling the Space Shuttle) was investigated.
Open Access
Fault diagnosis of distributed systems : analysis, simulation and performance measurement.
(1992-01) Mohammed, Thabit Sultan; Andrew, R.
Fault diagnosis forms an essential component in the design of highly reliable distributed computing systems. Early models for diagnosis require a global observer, whereas the diagnosis is shared between the systems nodes in later models. These models are reviewed and their different diagnosability properties reconciled. The design of improved fault diagnosis algorithms for systems without a global observer provides the main motivation for the thesis. The modified algorithm SELF3 [Hoss88] is taken as a starting point. A number of communication architectures used in distributed systems are reviewed. The properties of diagnosis algorithms depend strongly on the testing graph. A general class of testing graphs, designated as H-graphs, (which are a generalization of Dꞩṭ graphs introduced in [Prep67]), are investigated and their diagnostic properties determined. A software simulator for distributed systems has been written as the main investigative tool for diagnosis algorithms. The design and structure of the simulator are described. The diagnosis process is measured in terms of diagnostic time and number of messages produced, and the factors upon which these quantities depend are identified. The results of simulation of a number of systems are given under various fault conditions. A modified way of routing diagnosis messages, which, especially in large system s, results in a reduction in both the number of diagnosis messages and the time required to perform diagnosis, is presented. The thesis also contains a number of specific recommendations for improving existing self-diagnosis algorithms.
Open Access
The feasibility of liberalisation or deregulation of air transport in the GCC
(1992-05) Al-Suliaman, Saed; Hofton, A. N.
Many nations worldwide have been influenced by the experience of the USA in airline deregulation and have begun to consider the reform of their own governmental regulations. However, airline deregulation has both advantages and disadvantages for consumers, individual airlines, shareholders, the airline industry and governments. Western Europe has been under pressure to relax its regulations and introduce a liberalisation process. This pressure came partly from the outside as a result of the USA experience and the challenge from low cost Asian carriers. However, pressure also came from the inside from the European Commission and consumer organisations. In May 1981, the Gulf Cooperation Council (GCC) was established between Saudia Arabia, Qatar, U.A.E., Kuwait, Bahrain and Oman. One of the ways to achieve the GCC’s goal of confederation is through economic integration, which means the establishment of a Gulf Common Market. The main objective of this thesis is to research the feasibility of airline liberalisation in the GCC, taking into consideration the US experience and the European expectation in this particular field. To accomplish that objective, this thesis is divided into three parts. The first part analyses and studies the GCC air transport market, the development and impact of the US Airline Deregulation Act and the European liberalisation process. The second part develops a feasibility model for air transport liberalisation in the GCC. This model involves modelling demand for domestic GCC scheduled air services, fleet planning and aircraft selection, financial analysis and the possibility of a new GCC network. Finally, the third part sets out the conclusions from this theoretically based feasibility study of air transport liberalisation in the GCC, the main findings of the thesis and lessons that were learned from the USA and Europe. Its principal conclusion that liberalisation is both feasible and desirable is backed up with an outline of a possible first step that could be adopted for introducing an airline liberalisation process to the GCC market. This process starts by liberating intra-GCC services using aircraft of less than 70 seats capacity. On a practical level, the thesis also recommends that the Air Transport Section of the GCC Department of Transportation should co-ordinate changes to GCC institutions and infrastructure and should propose further changes to regulation as the liberalisation process moves ahead. It recommends that the Air Transport Section should use developments of this model to evaluate additional changes to the framework of regulation.
Open Access
Performance in sampled data systems
(IEEE, 1992-05-01) Whidborne, James F.
A performance index for control systems has been defined as the supremum of the absolute error that occurs over all time and all inputs. The input to the system is known only to the extent that it belongs to a known function space. The paper shows how this performance index is determined for certain sampled data systems with an input space characterised only by a bound on the derivative of the input. An example of a design using this performance index is given.
Open Access
Objective on line assessment of the performance of flux cored wires by real time computer based monitoring
(1993-04) Chawla, Kawalprit Singh; Norrish, J.
The aim of this research was to devise an innovative technique to obtain an objective assessment of the quality performance of tubular cored wires by sensing and measuring the signals available during welding. The work comprised: Identification of the parameters to assess. A study of the different monitoring techniques. Design of specific quality evaluation methods. The production of a system which allowed a quality index of welding performance to be obtained. Initially, the arc voltage, arc current, wire feed rate, arc light and arc sound signals were identified as possible sources of useful information. After a useful technique was accepted, the non-useful techniques were abandoned and a quality measuring instrument was built. The work involved development of statistical analysis techniques, Fast Fourier Transforms and mathematical modelling. A new approach to process modelling was devised which provided an objective and very flexible method of assessing, comparing and developing welding consumables. The final system was evaluated against conventional subjective assessment techniques and very good correlation was obtained.
Open Access
EMS control system design for a Maglev vehicle - a critical system
(Elsevier, 1993-09-01) Whidborne, James F.
For the effective operation of a magnetically levitated (maglev) vehicle using electro-magnetic suspension, it is necessary that the airgap between the guideway and the levitating magnets is maintained. Such systems, where the output is required to remain strictly within bounds, are known as critical systems. This paper describes the design of the suspension system for a high-speed maglev vehicle which ensures that the airgap is maintained.
Open Access
A study of receptivity and technology transfer in small engineering companies.
(1993-10) Anstey, Mike; Seaton, R. A. F.
This thesis addresses the problem of facilitating technology transfer to SMEs (Small and Medium Enterprises). The research sets out to explore the existing body of knowledge relating to the problem, and then by means of field research to seek pointers towards solutions. The thesis builds on earlier research which identified weaknesses in the activities of information centred technology transfer intermediaries and called for a more interactive and consumer centred approach. The research is particularly concerned with the concept of the ’Receptivity’ of SMEs to the technology transfer process. The concept of ’Receptivity’ is examined in the context of a wider conceptual framework. The field research explores the problems and plans of a small sample of engineering companies in Luton as perceived by the owners or managing directors of the SMEs. The field research then seeks to establish how the same group perceive solutions to the identified problems and requirements to achieve identified plans. The research suggests that the SMEs in the sample did not perceive the acquisition of technology as a problem nor did they perceive technology as a solution to their problems, or as a means to achieve their plans. Conclusions are drawn and implications discussed.
Open Access
Hydrogen concentration measurements using a gel-filled electrochemical probe
(Cranfield University, 1993-12) Allcock, Bryan W.; Robinson, M. J.;
A novel gel-filled electrochemical hydrogen probe was developed and used to measure hydrogen concentrations in carbon-manganese steels. The results were compared with those from an electrochemical permeation technique and a volumetric method. The probe was used to determine the distribution of hydrogen in 5mm steel plates cathodically charged on one side to represent the wall of a pipe or pressure vessel used in hydrogen service. The concentration measurements obtained by the three techniques were in good agreement with each other and with those predicted from diffusion equations and this permitted the precise boundary conditions on the charged metal surface to be determined. Surface reaction kinetics were investigated to model the hydrogen distribution and these were solved using solutions to Fick's diffusion equations. After long charging times the hydrogen concentration on the efflux surface of the plate approached that on the influx side, indicating that an almost uniform hydrogen distribution had been established. Rather than rapid loss of hydrogen from the free surface, as had been assumed previously, it was clear that there was a large resistance to hydrogen transport across the metal/air interface. Microstructural damage was examined both optically and using the scanning electron microscope. Separate investigations were carried out to help understand the effect that reversible and irreversible trapping had on the diffusion of hydrogen through the steel.
Open Access
Investigation into fusion boundary carbon diffusion in 1/2Cr1/2Mo/1/4V weldments
(1994) Smith, P. A.
The steam lines in the majority of power stations operating in the UK were fabricated from kCrkMokV steam pipe material joined using 2CrMo weld metal. Throughout the life of these systems, which operate typically at 565°C and 165bar, weldment cracking problems have been encountered. Many of these problems are well understood and are managed effectively. In recent years a creep cracking mechanism in the heat affected zone adjacent to the fusion boundary has been identified, referred to as Type IIIa cracking. This project has identified significant carbon migration across the fusion boundary of these weldments, from the lower alloyed kCrkMokV to the more highly alloyed 2CrMo weld metal. Carbon diffusion has been identified as occurring during the welding cycle, however the majority of carbon diffusion occurs during post weld heat treatment and particularly during service exposure. Carbon migration results in marked reduction in carbon content in the heat affected zone adjacent to the fusion boundary with a corresponding band of enhanced carbon content in the weld metal adjacent to the fusion boundary. The width of these areas increase with time at temperature. Micro hardness measurements have confirmed a reduction in the hardness of the heat affected zone region as a result of carbon diffusion. Hardness measurements have also pointed to a step change in hardness across the fusion boundary. This may result in a corresponding step change in creep properties. It is suggested that this mismatch in creep properties, coupled with a predominantly fine grained microstructure at the fusion boundary, can result in the fusion boundary heat affected zone region being the weakest region of the weldment.
Open Access
The design and analysis of a reconfigurable flight control system for advanced civil aircraft
(1994-04) Oliva, A. P.; Cook, M. V.
This work is concerned with the design of a pitch-rate-command-attitude-hold command and stability augmentation system in order that the augmented aircraft meets the Gibson dropback criterion, the Gibson phase-rate criterion and MIL-F-8785C requirements. The work shows two methods of design, pole-placement and optimal control, and discusses the design procedures, the advantages and disadvantages of each method. The work is also concerned with the redundancy aspect of the control law design, and so not only a sensor based design bu also an observer-based design are investigated. In order to design the observer-based control law. a Doyle-Stein observer was implemented. Two methods showing how to design the observer are discussed and presented, and the special characteristics of this kind of observer are also considered. The performance of the observer-based control law was compared with that of the sensor-based control law. The failure transients and characteristics of the control law are also studied and presented. Finally an evaluation of the control law was carried out with a non-linear model of the B-747 aircraft, and a simple altitude-hold autopilot was designed to work together with the stability augmentation control law.
Open Access
Robust controller design using h-infinity loop-shaping and the method of inequalities
(IEEE, 1994-12-01) Whidborne, James F.; Postlethwaite, I.; Gu, Da-Wei
A new approach to robust controller design is proposed. By using plant-weighting functions as the design parameters, the approach combines the method of inequalities with robust stabilization of normalized coprime factor descriptions of the weighted plant to design explicitly for closed-loop performance and stability robustness. A procedure for the design of robust two degree-of-freedom controllers is presented and is illustrated on a high-purity distillation column example
Open Access
Reliability analysis for subsea pipeline cathodic protection systems /
(Cranfield University, 1996-10) Trille, Christophe; Strutt, J. E.
Subsea pipelines, as the main transportation means for oil and gas produced offshore, are a key element of the production system. Cathodic protection systems (CPS) are used in combination with surface coatings to protect the pipeline from external corrosion. Although cases of pipeline failure due to external corrosion remain rare, such failures can have catastrophic effects in terms of human lives, environment degradation and financial losses. The offshore industry was led to the use of risk analysis techniques subsequent to major disasters, such as Piper Alpha and Alexander Kjelland. These accidents made the development and use of risk analysis techniques of highly significant interest, and reliability analysis is presently becoming a more important management tool in that field for determining reliability of components such as pipelines, subsea valves and offshore structures. This research is based on an analysis of subsea pipeline cathodic protection systems and on a model of the electrochemical potentials at the pipeline surface. This potential model uses finite element modelling techniques, and integrates probabilistic modules for taking into account uncertainties on input parameters. Uncertainties are used to calculate standard deviations on the potential values. Based on the potentials and potential variances obtained, several parameters characteristic of the cathodic protection system reliability, such as probability of failure and time to failure, are calculated. The model developed proved suitable for simulating any pipeline, under any environmental and operational conditions. It was used as a reliability prediction tool, and to assess the effects of some parameters on the cathodic protection system reliability.
Open Access
Downhole manipulation systems for abrasive jet cutting on oil wells.
(1997-08) Aldridge, Antony; Allwood, R. L.
This project investigates the possibility of using abrasive water jets for cutting operations inside oil wells and presents the associated procedures and tools required. Through-tubing window cutting was identified as an application of particular interest to the oil industry. This involves cutting a hole in the well casing, below the production tubing, so that a new well can be directionally drilled through it and into the producing formation. The study showed that through-tubing window cutting is a feasible application for abrasive water jets. The main findings are: • a 2.5 m by 0.1 m window can be cut in 10 mm thick casing in approximately 12 hours. This assumes that the window is 3000 m from the surface and that a surface pressure of 595 bar is used. • a manipulator has been designed in detail, based on a pressure balanced cylinder, which can move the nozzle smoothly and accurately over the complete surface area of the window. The maximum outer diameter is 53 mm and it would be deployed on VA” coiled tubing. Test rigs have confirmed the operation of critical components of the design. • several aspects of the design still need to be tested. A prototype manipulator should be built to demonstrate that it can repeatedly cut the same size of window and operate continuously for over 20 hours. • the pressure balanced design principle is applicable to any abrasive water jet cutting manipulator in which the nozzle is perpendicular to the direction of the well. Two examples are perforation of short sections of casing and cutting around the circumference of the production tubing for removal. • a specially designed cutting fluid with appropriate polymer additives must be used to give excellent solids carrying properties and low pressure loss. Their effect on cutting performance and hole cleaning efficiency needs to be tested.
Open Access
Learning control of automotive active suspension systems
(1997-09) Watanabe, Yukio; Sharp, Robin S.
This thesis considers the neural network learning control of a variable-geometry automotive active suspension system which combines most of the benefits of active suspension systems with low energy consumption. Firstly, neural networks are applied to the control of various simplified automotive active suspensions, in order to understand how a neural network controller can be integrated with a physical dynamic system model. In each case considered, the controlled system has a defined objective and the minimisation of a cost function. The neural network is set up in a learning structure, such that it systematically improves the system performance via repeated trials and modifications of parameters. The learning efficiency is demonstrated by the given system performance in agreement with prior results for both linear and non-linear systems. The above simulation results are generated by MATLAB and the Neural Network Toolbox. Secondly, a half-car model, having one axle and an actuator on each side, is developed via the computer language, AUTOSIM. Each actuator varies the ratio of the spring/damper unit length change to wheel displacement in order to control each wheel rate. The neural network controller is joined with the half-car model and learns to reduce the defined cost function containing a weighted sum of the squares of the body height change, body roll and actuator displacements. The performances of the neurocontrolled system are compared with those of passive and proportional-plusdifferential controlled systems under various conditions. These involve various levels of lateral force inputs and vehicle body weight changes. Finally, energy consumption of the variable-geometry system, with either the neurocontrol or proportional-plus-differential control, is analysed using an actuator model via the computer simulation package, SIMULINK. The simulation results are compared with those of other actively-controlled suspension systems taken from the literature.