Development of Self-Maintenance Photocopiers

Yoshiki Shimomura and Sadao Tanigawa, Mita Industrial Co., Ltd., Japan; Yasushi Umeda and Tetsuo Tomiyama, The University of Tokyo

The traditional reliability design methods are imperfect, because the designed systems aim at less faults but once a fault happens they may hard- fail. To solve this problem, we propose the con- cepts of self-maintenance machine (SMM) that can maintain its functions flexibly even though faults happen. In order to achieve capabilities of diagnosing and repair planning, a model based approach that employs qualitative physics is proposed. Regarding repair executing capability, control type repair strategy is proposed. A prototype of the self-maintenance machine is devel- oped and it succeeded to maintain its functions as far as its structure does not change. This prototype, however, revealed the following problems that may arise when applied to a commercial product as embedded software. The problems include; (1)performance of the reasoning system, (2)the system size, (3)effects of environmental changes, and (4) roughness of qualitative repair operations. In order to solve these problems, we propose a new reasoning method based on vir- tuul cases and fuzzy qualitative values. This is a methodology of knowledge compilation that gives better reasoning performance and can deal with real world applications like the self-maintenance machine. By using this method, we finally developed a commercial photocopier that has self-maintenability and is more robust against faults. The commercial version has been supplied world-wide as a product of Mita Industrial Co., Ltd., since April, 1994.

This page is copyrighted by AAAI. All rights reserved. Your use of this site constitutes acceptance of all of AAAI's terms and conditions and privacy policy.