On-line gap measurement techniques for steel mill non-contacting conveyance system, which can supply accurate, rapid and high-sampling rate gap measurements, have been proposed. To realize the entire process, by considering the operational environment in a steel mill and combining with those available system dimension measurement instruments, an image-based scheme with proper image processing and parameter calibration process has been developed. The possible sources that affect the air-gap detection accuracies have also been thoroughly investigated, and a comprehensive measurement database and a recursive modification technique have been successfully established. In order to achieve stable control for site implementation, an integrated optical inspection system which combined with the high-speed rate line-scan camera has been designed. From the experimental results, the proposed system can both provide accurate gap values at the static state, and offer stable control operations at the dynamic state. It is believed that the proposed scheme provide innovated guidance for the related conveyance applications in the steel mill.

The objective of this thesis is to report the concept of driving a non-contacting steel plate conveyance system with a DSP-based closed-loop control structure. The lift force of the system is first estimated from the magnetic equivalent circuit (MEC) analysis, and the estimation results have been verified through three-dimensional finite element analysis (3-D FEA). Based on the force calculations and the fuzzy control theory, a closed-loop control structure has been designed. Through accurate signal detections, a real-time lift force control of the conveyance system can be realized. Finally, by feeding AC sources with DC bias to the stator windings of the motor, the lift and propulsive forces can be supplied to the steel plate simultaneously.

Based on the design concepts of linear induction motors, a non-contacting steel plate conveyance system for steel mill application has been constructed. To reduce the noise and friction from conventional roller conveyance system, the designed system is aimed to simultaneously provide adequate lift, propulsive, and guide forces to the steel plate. At first, the preliminary understandings of the characteristics of lift force have been gained through the simple magnetic circuit analyses, and together with other mechanical concepts develop the laboratory prototype. Then, through three-dimensional finite element analyses and state model developments, the system¡¦s static and quasi-dynamic/dynamic operational characteristics are investigated. Finally, the validity of this system has been verified by experimental measurement. Thus, the analyses and results of the experiment clearly show that the designed non-contacting steel plate conveyance system is certainly feasible.

A non-contacting steel plate conveyance system based on the linear induction motor scheme, which can provide lift and propulsive forces simultaneously, is proposed. It has the features of high power density, direct drive, simple mechanical structure, and being able to reduce the operation noise. A magnetic equivalent circuit method and electromagnetic theory incorporating with 3-D finite element analysis are involved to investigate the static and quasi-dynamic properties and confirm the electrical and mechanical designs. To realize the dynamic behavior and develop the closed-loop control, a proper stationary reference frame transformation of the system voltage equations is also introduced. By considering the practical operational environment, a fuzzy-based control structure integrated with remote optical measurement system has been established and implemented by a DSP-based controller combined with required peripheral circuits. The experimental results show the applicability of such control strategies. With the systematic procedures for design, analysis, and control provided in this dissertation, implementation feasibility of the proposed system can be conveniently demonstrated.