Papers by Author: Dong Hwan Choi

Abstract: The brake system is very important part of the machine working. The mooring winch brake holds the ship on the harbor. But sometimes it appeared the excessive stress and brake lining would be broken. So it is necessary to change the shape of brake system with improve the durability of brake band. In this research, three models, such as a single brake shoe with a uniform thickness, a dual brake shoe with a uniform thickness, and a dual brake shoe with different thickness, are adopted as analytic model. In order to evaluate the strength of band brake according to the shape of brake shoe, the finite element analysis for three models is carried out by using ANSYS Workbench.

Abstract: The operation error of a robot that occurs inevitably due to the manufacturing tolerance needs to be controlled within a certain range to achieve proper performance of the robot system. The reduction of manufacturing tolerance, however, increases the manufacturing cost in return. Therefore, design engineers try to solve the problem of maximizing the tolerance to reduce the manufacturing cost while minimizing the operation error to satisfy the performance requirement. In the present study, a revolute joint model considering uncertainties due to joint clearance is employed to perform a reliability analysis of the robot manipulator operation. The reliability analysis procedure employs single Monte-Carlo simulation and a statistical relation between the tolerance and the operation error. Significant reduction of computing time can be achieved with the proposed method. The present method is especially effective if sensitivity information is hard to be obtained for the analysis.