For a build-up type modular tool system used for boring, a boring bar is constructed by combining basic parts such as a shank (or basic holder), accessories, boring head, tip holder, and cutting edge to match the shape and properties of work. The individual basic parts, however, are of such diverse kinds that they provide a vast number of combinations. For this reason, a considerable length of time is required for selection of an optimum combination of basic parts, and this considerably reduces the intrinsic value of the build-up system requiring less time in fine adjustment of cutting edge and tool wear correction. This paper discusses an expert system developed for higher accuracy and speed in selection of an optimum combination of basic parts for a modular boring tool system. We have only to specify the shape of work, its material quality, etc. in the conversational mode. The expert system will then select an optimum combination of basic parts, and will output the result of selection, cutting rate, feed rate and other boring conditions in a short time.
Pinto et al. (1983) have treated an assembly line balancing with processing alternatives where the choice of manufacturing alternatives and the assignments of work elements are simultaneously determined. Their model, however, is based on the partially-automated assembly line and the processing alternatives can be applied only to the specific work elements. This paper treats a line balancing problem with fully automated and flexible assembly machines to be installed in each station. Some stations, have a decision plan on the choice of the alternative machine with a higher cost but a higher performance. The assignment of work elements and the decisions on the use of alternative machine are simultaneously determined to maximize the profit per unit of time yielded by the line. An algorithm to maximize the profit per unit of time is proposed through the Branch and Bound method.
In recent years, H∞ control design has been vigorosly studied, and some design schemes have been established. However, the solution of H∞ control problems is, in general, not uniquely determined, and there are some freedom in the choice of the solution. Therefore, there arises a problem how to determine the free parameters to improve the closed loop properties. Especially. pole placement of closed loop system is the most important one, because it is not easy to express by H∞ norm. In this paper, we treat this problem in the context of the robust control system, whose H∞ norm of the complementary sensitivity function is minimized by state feedback control. At first, we consider asymptotical pole placement of a closed loop system using central solution, which is obtained by setting free parameters to zero. As a result, it is shown that some poles of this system are close to imaginary axis, when H∞ norm of the complementary sensitivity function is minimized. Next, we investigate the design of a robust control system whose poles are located at desired places, and show that it is possible to set almost all poles of closed loop system freely, if only we make one pole close to -∞. Therefore, it is made clear that there remains much freedom in the selection of robust controller.
A procedure is proposed which can subjectively estimate the relative occurrence probability of each fundamental event in fault tree by applying a pairwise comparison method. The proposed procedure could be applied to calculate the subjective criticality importance for the fundamental event. Consequently, it is possible to estimate the effect of the variation in the occurrence probability of each fundamental event on the variation in occurrence probability of top event, even if some of probability data for fundamental event should be lacking.
As a new control method for systems with unknown dynamics, the Time Delay Controller (TDC) has been proposed. The TDC has the characteristics of both simple control algorithms and quick response, and its validity has experimentally been shown for robot manipulators and heat pump systems. This paper discusses design aspect of the TDC for single-input-single-output linear systems. Under the assumption that a small time delay is implemented by a shift operator in discrete time domain, stability and model following property is analyzed. Based on the analysis, a guideline is given for the choice of the two major design parameters, which are a time delay and an estimated value of a control coefficient. Finally, the proposed guideline's usefulness is evaluated by simulation for second order systems.