Robust shape control in a sendzimir cold-rolling steel mill

The shape control problem for a Sendzimir 20-roll cold rolling steel mill is characterised by operation over a wide range of conditions arising from roll changes, changes in rolling schedules and changes in material gauge, width and hardness. Previous approaches to the problem suggest storing a large number of precompensator matrices to cater for the full range of operating conditions. This paper, on the other hand, attempts to synthesise a controller which is optimally robust to changes in the conditions associated with the rolling cluster, resulting in a reduced storage requirement for the controlling computer. The performance of the robust controller is evaluated via nonlinear simulation

Practical Challenges in Harvesting Wave Energy

This paper examines the challenges of efficiently harnessing wave energy. A variety of energy conversion device types is reviewed and a generic heaving buoy device selected for detailed examination. A number of modelling and control challenges are detailed and a hierarchical control structure is indicated. Both potable water production and electricity generation are included as possible uses of such devices and each presents separate control challenges

Diagonalisation of a class of multivariable system via an actuator linearisation technique

Many multivariable (systems with many inputs/outputs) industrial processes can, to a good degree of approximation, be modelled by a transfer function matrix, where all of the interaction occurs in a matrix of constant coefficients. This reflects the fact that the dynamics of the section in which the interaction occurs are very fast compared with the other dynamics in the system. Examples of such systems include steel rolling mills and boiler systems. Such multivariable systems are relatively easy to design controllers for, since the system may be diagonalised by an inverse of the constant gain matrix, followed by suitable single-loop dynamic compensation. However, this approach depends on the linearity of the dynamical elements in the system. Such a condition is voilated by the presence of non-linear actuators, which are a feature of many industrial systems. The presence of such actuators within a multivariable control system as described above can cause very significant interaction problems, with associated degradation in performance, particularly during transients. This paper describes a straightforward technique, which is effective in linearising typical non-linear industrial actuators, allowing diagonalisation to be effectively achieved at all frequencies. The technique relies on a simple describing function analysis and manifests itself as a time-varying linearising precompensator for each non-linear actuator. A simple example is used to demonstrate the effectiveness of the method and it is then shown in application with multivariable boiler and steel mill models

Electronic engineering education - an Irish perspective

This paper describes the current approach to electronic engineering education in the School of Electronic Engineering at Dublin City University. Since the first student intake in 1979, the University has developed a range of programs to suit the needs of Irish industry, from the B.Eng degree (with single subject certification) to masters and doctoral programs with research and coursework options. In addition, the School of Electronic Engineering is committed to providing Continuing Engineering Education (CEE) which, for the most part, is integrated with the full time taught courses. Some attention is paid to the industrial training component in the undergraduate program which has been a controversial issue in Irish universities. In addition, the position of graduates within the EC is examined

Comparison of Ceramic Waste forms Produced by hot Uniaxial Pressing and by Cold Pressing and Sintering

Synroc C waste form specimens prepared using the Australian-developed technology are uniaxially pressed in stainless steel bellows at 1200{degrees}C and 20MPa. This produces a material with high chemical and physical durability and with the radioactivity enclosed inside both the waste form and the bellows. An alternative method of producing the ceramic product is to use cold pressing of pellets followed by reactive sintering to provide densification and mineralization. Depending on the scale of waste form preparation required and on the activity level and nature of the waste streams, the cold press and sinter method may have advantages. To evaluate the effects of production method on waste form characteristics, especially resistance to dissolution or leaching of waste elements, we have prepared two simulated waste samples for evaluation. Both samples were prepared from liquid precursor materials (alkoxides, nitrates, and colloidal silica) and then doped with waste elements. The precursor material in each case corresponded to a basic phase assemblage of 60% zirconolite, 15% nepheline, 10% spinel, 10% perovskite, and 5% rutile. One sample was doped with 25% by weight of U; the other with 10% by weight each of U and Gd. Each sample was calcined at 750{degrees}C for 1 hr. in a 3.5% H{sub 2} in N{sub 2} atmosphere. Then one portion of each sample was hot pressed at temperatures ranging from 1120 to 1250{degrees}C and 20MPa pressure in steel bellows. A separate portion of each sample was formed into pellets, cold pressed, and sintered in various atmospheres at 1200{degrees}C to produce final products about 2/3 cm in diameter. Samples were then examined to determine density of the product, grain sizes of the phases, phase assemblage, and the location of the U and Gd in the final phases. Density data indicate that sintering gives good results provided that the samples are held at 200{degrees}C for long enough to allow trapped gases to escape

Electronic engineering education - an Irish perspective

This paper describes the current approach to electronic engineering education in the School of Electronic Engineering at Dublin City University. Since the first student intake in 1979, the University has developed a range of programs to suit the needs of Irish industry, from the B.Eng degree (with single subject certification) to masters and doctoral programs with research and coursework options. In addition, the School of Electronic Engineering is committed to providing Continuing Engineering Education (CEE) which, for the most part, is integrated with the full time taught courses. Some attention is paid to the industrial training component in the undergraduate program which has been a controversial issue in Irish universities. In addition, the position of graduates within the EC is examined

Control techniques for ocean energy applications.

Control systems, despite often being `invisibly' incorporated within products, devices and vehicles, are ubiquitous. They are prevalent within the automotive and aerospace industries and form part of the vanguard of technologies in in- creasing performance, improving fuel economy and increasing safety. One of the most appealing aspects of incorporating control technology in many systems is that the addition of extra control functionality can usually be achieved merely through the addition of extra software code though, in many cases, additional sensors and actuators may be required. This relatively simple implementation modality masks both the capability of control systems and the high level of engineering underpinning the devel- opment of a suitable control algorithm. For example, many high-performance model-based control design methods require an accurate mathematical model of the system to be controlled and a significant number of man-hours can be absorbed in modelling. Nevertheless, there is usually a good case to be made for the incorporation of control technology to improve the performance (both technical and economic), reliability and safety of a system. In this chapter, we will examine the role that control engineering can play in making ocean energy technology more competitive

Making Lectures Come Alive With a Data Projector

The relatively recent advent of widely available data projectors, coupled with the availability of CAD packages for control systems with graphical input/output facilities provides a mechanism for transforming lectures into shows where students can see control systems come alive. Experiences over a range of control systems courses at Dublin City University (DCU) have been positive, where a data projector has been used over a trial period of eighteen months