Special Issue on Flexible Force Control and Process-Adaptive Production Systems
Professor, Dr.-Eng.Graduate School of Science and Technology Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan
In the recent assembly lines, the frequency of changing processes has been increasing in line with high mix production, but because these changes are carried out by operator, the burden of changing processes has increased as well. This situation has arisen because of the fact that since the robots being used at present automatic assembly lines are based on a simple teaching and playing back method, human workers must renew instructions for each act of changing a work object and also that dedicated machines are necessary due to the inability of making precision assembly,thereby inviting declines in total operational rates and increases in cost. These facts are limiting the use of robot based automation itself and are one of the important factors for the declining international competitive power. Under these circumstances, with the aim of constructing sophisticated production systems that are capable of dealing with process changes automatically without the use of human labor, a project called “Research & Development of Process Adaptive Flexible Robots”was proposed and was adopted to the Regional Consortium Research and Development Enterprise supported by the Ministry of Economy, Trade and Industry and by the New Energy and Industrial Technology Development Organization, and was adopted. The research period was to be 3 years from the fiscal year 1997 to the fiscal year 1999, and the total research fund was to be 360 million yen. In more specific terms, an engine assembly line and a semiconductor testing process were chosen as research subjects; and developmental research was carried out for elemental techniques that are necessary for the flexible execution of tasks such as piston insertion causing no damage to walls even with a minute clearance, or IC chip insertion causing no plastic deformation even with positional dislocation, though these tasks must be carried out when works change in type, size, etc.; and the researchers started the work of developing system integration technology that would achieve these task objectives in the optimal manner. Attention was focused rather on “force control” of which humans make skillful use than on developmental work based on the conventional position control technology, and development objectives were set not only to achieve a breakthrough for putting force control technology into practice by way of the integration of flexible force control and high aprecision position control and also by way of controlling the vibrations of complex machine systems, but also to demonstrate the research results by means of two prototypes of a flexible robot for assembly lines and an inserter for IC chip testing. The present special issue is a collection of results achieved by the participating research organization in the present research and development work, and it will be a great pleasure for its editors if this issue contribute seven a little. toward the future practical use of force control. Finally, sincere appreciation is expressed to the Ministry of Economy, Trade and Industry and the New Energy and Industrial Technology Development Organization for providing an opportunity for carrying out this research and development work, as well as to all the organizations for their participation in the project.
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