Feed-forward Line Research Articles

Two Degrees of Freedom in the Control of a DC-DC Boost Converter, Fuzzy Identified Explicit Model in Feed-forward Line

We present a novel approach to the fuzzy control of a DC-DC Boost Converter. Using heuristic partitioning of the main control parameters and focusing on global knowledge of the open-loop, stable sy...

FTL with feed-forward optimal design by discrete event production simulator with GA

This article formulates a new optimal design problem of a flexible transfer line with feed-forward lines (FTL-FF). The machine tools and the buffer size are included to find the optimal design of the FTL-FF that achieves a greater production rate of the FTL-FF. Machine tools with different performances are selected from a list of products available in the market. To solve this problem, a discrete event production simulator (DEPS) in conjunction with genetic algorithm (GA) is proposed. The GA methodology is based on a technique that is called multi-group arrangement method (MGAM) which arranges the genes in individuals. Numerical examples ascertained that after a number of operations based on the combination of DEPS and GA, the nearest optimal design of FTL-FF is found.

Overlapping Decomposition: A System-Theoretic Method for Modeling and Analysis of Complex Manufacturing Systems

A system-theoretic method, referred to as overlapping decomposition, is presented to evaluate the performance of a complex manufacturing system with assembly, parallel, rework, feedforward, and scrap operations. The idea of the method is to decompose the complex system into a set of serial production lines, with the first or last machines of each serial line overlapped with another line, and to modify the parameters of overlapping machines to accommodate the effects of machines and buffers in other lines. Iterative procedures are introduced to estimate the system production rate. The convergence of the procedures and the uniqueness of the solutions are proved analytically and the accuracy of the estimates is evaluated numerically. Note to practitioners - Many large volume manufacturing systems consist of complex operations, for instance, assembly, disassembly, rework loop, parallel lines, feedforward lines, scrap, etc. Development of a performance evaluation method to provide fast and accurate analysis of system throughput is important for design and continuous improvements. This paper introduces a system-theoretic method, referred to as, overlapping decomposition, to analyze the performance of such complex manufacturing systems. The complex system is decomposed into overlapped serial production lines and modifications are introduced to accommodate the coupling effects among all these lines. From the theoretical point of view, this paper presents the proofs of the convergence of recursive procedures and the uniqueness of solution. From the application point of view, the method has obtained good results in solving practical problems on the factory floor.

Antiparallel Control Logic

This paper proposes a method, termed antiparallel control logic, for the control and efficient utilization of computer networks that exhibit substantial propagation delays on the lines interconnecting the logical elements, as well as in the elements themselves. The discussion encompasses the basic behavior of antiparallel stages that realize this method of control, including their logical realization and their extension to other useful network logic structures. In a strictly feedforward line, where the stored data are indexed forward by control pulses moving in a direction away from the data source, the existence of time variations in the delays of successive stages implies a nonzero probability that two successive control pulses will eventually appear at the inputs to a given stage so closely spaced that the basic reaction time of the stage is violated. The result is a failure of the transfer mechanism and a consequent loss of information. If feedback control is provided such that control pulses move in a direction opposite to the flow of information, that is, if the control and information flows are antiparallel, then the failure of the transfer mechanism does not cause an overlap in the information stored on the line, but rather leaves a void, or hole, which does not imply necessary information loss nor physically unrealizable storage requirements on the individual stages.