Strip tracking measurement and control in hot strip rolling

It is well known that poor strip tracking can lead to reducedproduct quality but also to mill delays. The resultingcosts for internal rejects, customer complaints and yieldlosses have historically been significant. Moreover, the severityof these issues increases dramatically when stripsbecome wider, thinner and harder. Ultimately the rollingprocess becomes completely unstable. Hence, to reducecost of poor quality for the current product mix as well asto enable product development it is vital that strip trackingis improved.Most strip tracking issues arise at the head or the tail ofthe strip. In the rougher mill the main issue is head camber,a shape defect of the bar where the head is curved. Aclear example of this shape is shown in Fig 1. Large headcamber of the transfer bar may result in further problemsdownstream in the finishing mill and should ideally thus beprevented.Another notorious problem closely related to strip trackingis tail pinching in the finishing mill. This is a phenomenonwhere the tail of the strip suddenly moves sideward’s andgets damaged right after it has left the previous stand. AnPoor strip tracking is one of the notorious problems threatening process stability in a hot strip mill. Theseissues often lead to tail pinching and in the worst cases even to cobbles. The main pillars of the strategy setout to tackle these issues for the Hot Strip Mills in IJmuiden are rougher mill camber control and finishing millstrip steering and tail control. For such applications, a camera based measurement system has been developedin-house that is simple, cost-effective and yet both accurate and robust. Moreover, as we show in this paper,the system has proven its merits both as a finishing mill interstand centerline deviation measurement aswell as a rougher mill camber measurement. In the latter application the measurement data can be used forautomatic levelling in the rougher mill. The results of production tests presented in this paper demonstrate thatthe camber measurement in combination with a basic rougher mill tilt set-up model is sufficient to reduce thetransfer bar camber significantly

Strip tracking in hot strip mills

In the finishing mill, steel strip is rolled from thick slabs through pairs of rollers housed in a continuous train of seven roll stands. As the strip is rolled, unwanted lateral movement, known as strip tracking, can cause the strip to collide with the edge of the mill. Strip tracking control is currently a manual operation, relying on the skill of the operators. When tracking is observed, the stand tilt is adjusted asymmetrically, causing a camber in the strip, steering it towards the centreline. Tracking control can be automated if a reliable measurement of position is available. A vision-based system was developed to measure strip position. Cooling water, steam, high temperatures and electrical noise create a hazardous environment for electronic equipment and hamper image analysis. Hardware was specified to protect all equipment against the environment. A novel image analysis method combining predictive elements, filtering and Bezier curve fitting was created to allow measurements to be made with large amounts of cooling water obscuring the strip edges. The measurement system was designed to integrate with the existing mill systems, using the OPC protocol for communication. The system was created as a development system with only two cameras included, but allowed for additional cameras to be easily added and automatically detected. The results of the system showed that the image analysis techniques were effective, providing an estimated final resolution of 3.5mm/pixel, with measurements ±2mm within 60% confidence. Hardware performance provided good protection of the equipment against the environment but poor quality installation limited overall system performance. A computer model was developed to simulate tracking behaviour in the mill with non-linear variations of strip properties across the strip. The model was not completed to a satisfactory standard capable of producing useful results but the theories described could be developed further.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Strip tracking in hot strip mills

In the finishing mill, steel strip is rolled from thick slabs through pairs of rollers housed in a continuous train of seven roll stands. As the strip is rolled, unwanted lateral movement, known as strip tracking, can cause the strip to collide with the edge of the mill. Strip tracking control is currently a manual operation, relying on the skill of the operators. When tracking is observed, the stand tilt is adjusted asymmetrically, causing a camber in the strip, steering it towards the centreline. Tracking control can be automated if a reliable measurement of position is available. A vision-based system was developed to measure strip position. Cooling water, steam, high temperatures and electrical noise create a hazardous environment for electronic equipment and hamper image analysis. Hardware was specified to protect all equipment against the environment. A novel image analysis method combining predictive elements, filtering and Bezier curve fitting was created to allow measurements to be made with large amounts of cooling water obscuring the strip edges. The measurement system was designed to integrate with the existing mill systems, using the OPC protocol for communication. The system was created as a development system with only two cameras included, but allowed for additional cameras to be easily added and automatically detected. The results of the system showed that the image analysis techniques were effective, providing an estimated final resolution of 3.5mm/pixel, with measurements ±2mm within 60% confidence. Hardware performance provided good protection of the equipment against the environment but poor quality installation limited overall system performance. A computer model was developed to simulate tracking behaviour in the mill with non-linear variations of strip properties across the strip. The model was not completed to a satisfactory standard capable of producing useful results but the theories described could be developed further

Cal Poly Supermileage Steering System

The following report outlines the full design process that the senior project team went through to develop a steering system for the 2018 Cal Poly Supermileage vehicle from the development to the manufacturing and testing of the senior project steering system. The team was successful in reducing the weight of the steering system from 12.64 to 5.85 pounds while remaining within the cost budget provided for the Cal Poly Supermileage team. The new steering system initially failed drop testing which resulted in the uprights pulling out of the bottom carbon supports. This failure was repaired with a small redesign to the steering system and retested. Testing shows that the steering system will be strong and stiff enough for proper implementation into the 2018 Supermileage vehicle. Learnings from this report will provide the club with valuable information and a prototype steering system to use as a platform to improve and implement in their 2018 competition vehicle

. Разработка цифровых алгоритмов управления приводами мехатронной системы реверсивной кле-ти толстолистового прокатного стана

Expanding the plate mill product range implies the improvement of control algorithms for the mechatronics control system drives of the reversing stands. The most important objectives include increasing the accuracy of geometric dimensioning and tolerancing, as well as improving the profile and surface flatness of rolled pro­ducts. The structure explaining the automatic ROLL-GAP CONTROL concept is provided, which allows controlling the thickness and gap between SMS-Demag AG rolls. This concept is implemented in the '5000' mill stand of Magnitogorsk Iron and Steel Works. The structural diagram of the automatic gauge control system (AGS) is presented. The functional diagram of the hydraulic gap control (HGC) system is presented, which includes a fast proportional control channel and a relatively slow integral position control channel. The principle of automatic thickness control is discussed, implemented in the automatic gauge control (AGC) system of the mill stand TCS controller. The diagram and dependences are prepared for the calculation of the nonlinear thickness controller parameters. The functions of the RAC regulator are described, intended for compensation of the tensile difference (gap spacing) at the mill stand sides. The dynamic impact compensation system functions are considered. The removal of the roll bending and deformation control signals is substantiated. The disadvantages of AGC are noted for sheets with a thickness below 10 mm. The most dangerous case is the tearing of metal fragments from the rear sheet side caused by the incorrect operation of the gauge control system. A method for hydraulic gap control is proposed based on the fast increase of the roll gap in the rear part of the rolled sheet during the last passage when rolling thin sheets. The results of experimental studies made on the '5000' mill are presented. The efficiency of the proposed control method has been confirmed. The oscillograms of signals are presented characterizing thickness variations. HGC and AGC systems with the proposed adjustments are proven to provide high-accuracy hydraulic position control and thickness control along the sheet length and width.При расширении сортамента продукции толстолистовых прокатных станов приобретает актуальность проблема совершенствования алгоритмов управления приводами мехатронной системы реверсивной клети. Важнейшими задачами являются повышение точности геометрических размеров, а также улучшение профиля и планшетности проката. Представлена структура, поясняющая концепцию ROLL-GAP CONTROLL автоматического регулирования толщины и зазора валков фирмы SMS-Demag AG. Данная концепция реализована на стане 5000 Магнитогорского металлургического комбината. Приведена структурная схема системы расчета и автоматического регулирования толщины (САРТ). Рассмотрена функциональная схема системы регулирования положения гидравлических нажимных устройств Hydraulic Gap Control (HGC), включающая быстродействующий канал пропорционального регулирования и относительно медленный канал интегрального регулирования положения. Рассмотрен принцип автоматического регулирования толщины, реализованный в ресурсе системы Automatic Gap Control (AGC) контроллера TCS клети. Представлены схема и зависимости для вычисления коэффициентов нелинейного регулятора толщины. Отмечены функции RAC-регулятора, предназначенного для компенсации разницы растяжений (перекоса) зазора по сторонам клети. Рассмотрены функции системы динамической компенсации возмущающих воздействий. Обосновано исключение сигналов коррекции противоизгиба и деформации валков. Отмечены недостатки САРТ при прокатке листов толщиной менее 10 мм. Наболее опасным является отрыв фрагментов металла от хвостовой части, вызванный некорректной работой системы задания толщины. Предложен способ управления гидравлическими нажимными устройствами, суть которого заключается в быстродействующем увеличении межвалкового зазора на «хвосте» раската в последнем проходе при прокатке тонких листов. Представлены результаты экспериментальных исследований, выполненных на стане 5000. Подтверждена техническая эффективность внедрения предложенного способа управления. Рассмотрены осциллограммы сигналов, характеризующих разнотолщинность. Доказано, что при предложенных настройках систем HGC и AGC обеспечивается высокая точность регулирования положения нажимных устройств и толщины по длине и ширине листа

Theory and practice of a horizontal-axis flexible sail type wind-turbine behaviour.

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

Examination of the factors affecting quality on continuous annealing processing lines.

The Continuous Annealing Processing Line (CAPL) of the Corus Strip Products UK integrated works in South Wales, United Kingdom, is one of the most modern lines of its type in the world. It produces thin and wide carbon strip steels of the highest quality in terms of metallurgical consistency, surface quality and dimensional tolerances. Tensioned strip can travel at a velocity of up to 600m/min at temperatures in excess of 750°C. The yield point of the strip is naturally reduced at these annealing temperatures; therefore the contact interaction that develops between the transport roll and the strip steel it is transporting is critical. The primary focus of research is on maintaining the elasticity of the strip steel as it passes through the furnace section of the continuous annealing processing line. In particular focusing on the heating and adjacent soaking sections of the CAPL, where the temperatures are at their highest. The thesis is concerned with the roll-strip interaction and its many different parameters - roll geometry, strip dimensions, strip tension and strip temperature. Research concentrated on the initial contact plane, where the strip first comes into contact with the transport roll. Results indicate that the strip's elastic stress- state is most affected by the fillet that circumnavigates the transport roll, especially where the fillet intersects the initial contact plane. The parameters chosen took into consideration the future operational commitments of the CAPL, because continual demand is always increasing the threshold. To perform the task assigned the author made use of extensive computational finite element method models. A second aspect of the research was to consider acceptable temperature differentials between the transport roll and the strip steel at initial contact. The strip has a low yield stress at its annealing temperature, thus an excessively high temperature differential will create a buckle risk. Therefore, an experimental programme was developed in conjunction with industrial partners Stein Heurtey to investigate acceptable temperature differentials for initial contact conditions

DESIGN AND FLIGHT TESTING OF A WARPING WING FOR AUTONOMOUS FLIGHT CONTROL

Inflatable-wing Unmanned Aerial Vehicles (UAVs) have the ability to be packed in a fraction of their deployed volume. This makes them ideal for many deployable UAV designs, but inflatable wings can be flexible and don’t have conventional control surfaces. This thesis will investigate the use of wing warping as a means of autonomous control for inflatable wings. Due to complexities associated with manufacturing inflatable structures a new method of rapid prototyping deformable wings is used in place of inflatables to decrease cost and design-cycle time. A UAV testbed was developed and integrated with the warping wings and flown in a series of flight tests. The warping wing flew both under manual control and autopilot stabilization

Active control of underwater propulsor using shape memory alloys

The development of a leading edge propeller blade reconfiguration system using Shape Memory Allow (SMA) muscles is presented. This work describes the design and testing of a leading edge flap, which is used to alter the local camber of a propeller blade. The leading edge flap is deflected by SMA wires housed in the blade and maintained in a fixed position with a shaft locking and releasing mechanism. A locking and releasing mechanism is utilized so that constant actuation of the SMAs is not required to maintain leading edge deflection. The profile at 70% span of the propeller blade was used to create a two-dimensional blade for leading edge flap design implementation and load testing. Deflection of up to five degrees was obtained with the final design of the leading edge flap and locking and releasing mechanism. The SMA muscles used to deflect the leading edge were actuated electronically through resistive heating and were controlled by a proportional/integral gain control algorithm with closed-loop feedback from a linear displacement sensor within the blade. With the final design of the leading edge flap and locking and releasing mechanism, a preliminary design for a three-dimensional propeller was created