Masanori Igoshi

Generation of Mechanical Assembly Sequences Considering Different Evaluation Viewpoints

We consider a new approach toward the generation of mechanical assembly sequences with computers. We propose an algorithm to generate the precedence constraints between parts considering the geometric interference during assembly. The precedence constraints are represented by an adjacency matrix. The number of assembly sequences can be estimated by a simple matrix manipulation without actually generating them. This allows designers or process planners to interactively reduce the number of sequences by regarding a subset of parts as a group, and considering other evaluation viewpoints. After the number of the sequences is reduced sufficiently, all feasible assembly sequences are generated based on the evaluation viewpoints selected by designers without a large amount of computation. An example demonstrates the practical efficiency of the proposed method.

Maintenance Support System Equipped with Monitoring Function

Computer support for maintenance workers is discussed. First, the difference between manufacturing work and maintenance work is considered, and the functional requirements of a computer support system are discussed. In order to meet these requirements, a work support system equipped with a monitoring function is proposed. The system is structured with three-layered subsumption architecture. As an application of the proposed system, a safety management system is introduced. Through developing the system, suitable computer models for realizing the support system are introduced and the advantage of the monitoring function is shown.

Simulation of Reflection Image Created by Infrared Light in Smoke-filled Environment.

In this study, in order to investigate visibility in a smoke-filled environment like a firefight scene, a simulation system was constructed using a transmission model and a reflection model based on experimental data. Scattering and absorption of smoke layers as functions of wavelength and smoke characteristics are derived from analyzing transmission of smoke with Mie-theory. Reflections of object surface are obtained by applied experimental data to Sparrows reflection model. With a result from the simulation, it shows good correspondence with real image, and scattering, absorption and reflection effect was clarified in visible and infrared image in a smoke-filled environment.

Testing the Stability of Subassemblies Using Geometric Model for Mechanical Assembly Planning.

Several criteria are required to reduce the number of feasible mechanical assembly sequences that are generated by a computer. One of them is the stability of subassemblies under gravity, since machines are generally assembled with as few supporting tools as possible. This paper presents a testing method of the stability of subassemblies using a 2-D geometric model. First, we introduce an assumption with respect to the pressure distribution over the line of contact between two parts. Based on this assumption, we model the forces by which parts act upon each other. An algorithm for deciding whether any part will fall using techniques of mathematical programming, is proposed. The computational results are shown in examples.