Department of Precision Mechanics

The proposed anthropocentric manufacturing system (AMS) scheduling method consists of a pre-process and a post-process. The pre-process is an estimation of the degree of job and technicians' characteristics in one lot of jobbing by a leader, using a skill-based manufacturing thought model. The post-process consists of skill level evaluation algorithm and GA algorithm. The estimated results are valuated to be technician's skill level on each job, using skill level evaluation algorithm; and GA initial populations construct the chromosomes by randomly selection high skill level technicians and their operable machines. An example of one lot of special parts is used for scheduling by this proposed method. The best result performs a maximum total skill level index (TSI) and a total earliness index (TEI); and a minimum man-hour index (MHI). The simulation results also ensure that the algorithm can solve the scheduling problems by limiting approximately 40% of manufacturing cell resources.

This paper describes the concept and functions of multilevel supervisory systems aimed at a more efficient operation of advanced flexible manufacturing systems. A supervisory system consists of a control system, an adaptation system, a process monitoring system and a machine failure diagnosis system. Thus supervisory systems assure the control of machining accuracy, the detection of human errors and tool breakage, and the identification of machine failures. This paper presents some successful results of the implementation of these subsystems.

This paper describes the general concept and the framework of a product model for design and manufacturing preparation. Machining preparation, such as process and operation planning, generation of NC cutter path, and geometrical and physical simulation of the machining operation, made by utilizing information stored in the preceding stages, are implemented at each stage. Finally the use of information is shown in a product model for off-line programming of robots and for geometric and physical simulation of robot operation.

This study proposes an anthropocentric manufacturing system (AMS) scheduling method and also examines the optimum pattern for skill-based scheduling based on leader decision, using three scheduling patterns. These are: (i) fixed machine type, (ii) invariable machine type, machine model and machining method for some jobs, and (iii) constant machining method. The scheduling process was divided into three stages, including the application of a thought model to help leaders determine the degree of match between the job and the technicians' characteristics, and the evaluation of the technician's skill levels for each job in relation to the job characteristics. Using scheduling performance indexes, evaluation by a total earliness index (TEI), a total skill level index (TSI), and a man-hour index (MHI) the analysis shows that the scheduling pattern (iii) was the best pattern for this proposed scheduling method because at a constant value of TEI and MHI, the TSI was highest when compared with the two other patterns. With this method, the leader needs to only determine the machining method as selections of suitable machine types and machine models for each job and technician will be decided by the GA mechanism.

Replacement of parts is a crucial task for the reuse of parts. In this paper, functions of part agent we are developing that support the reuse are described. A part agent manages life cycle of a part using a network agent and an RFID tag attached on the part and generates advices for the user on the maintenance of the part in order to promote the reuse. Part agent we are developing to support the replacement has the following functions. First function is to detect deterioration of the part from its sensory data. As an example, simple 3dof manipulator is developed with modularized link structure. Part agent is assigned for each module and generates advice on its replacement. Second function is to calculate the possibility of failures of part based on causal relation among user operations and detected events. Third function is to support users to disassemble used parts. Part agent generates disassembly procedure of the part and shows it to the user using augmented reality technique. In this paper, the planned scheme for part agent to support reuse of part with these functions is described and preliminary result of the development is shown.

Because the cost of performance testing using actual products is expensive, manufacturers use lower-cost computer-aided design simulations for this function. In this paper, we propose using hexahedral meshes, which are more accurate than tetrahedral meshes, for finite element analysis. We propose automatic hexahedral mesh generation with sharp features to precisely represent the corresponding features of a target shape. Our hexahedral mesh is generated using a voxel-based algorithm. In our previous works, we fit the surface of the voxels to the target surface using Laplacian energy minimization. We used normal vectors in the fitting to preserve sharp features. However, this method could not represent concave sharp features precisely. In this proposal, we improve our previous Laplacian energy minimization by adding a term that depends on multi-normal vectors instead of using normal vectors. Furthermore, we accentuate a convex/concave surface subset to represent concave sharp features.

Mass production and mass GQnsumption brings environmental problems and an exhaustion of resources ． Reuse of the product parts is a solution to shift frem the current society with mass production ／ consumption toward a sustainable recycling society ． However ， most consumers are abEe te neither find appropriate replacement parts from the market nor to provide the rnarket with the parts thcy do not require any more due to the lack of detaired knowledge ofthe product ， In order to solve this problem ， we are developing a part agent system with the 負lnctions to provide advices to consumers on when and which part ofthe product shouid be exchanged and on which part is appropriate fbr its rep 亘 acement ． In this report ， a function developed for the negotiation among part agents is described when two or more part agents looking for replacement parts want a samc part ．