A logarithmic profile is essentially optimal crowning geometry for rolling machine elements such as bearing rollers and raceways. Although some design methods of the profile have been proposed, they do not refer to the tolerance of the geometry required in engineering applications and in production. This paper shows how to define the tolerance range associated with the optimum roller profile, previously suggested by one of the authors. The overall tolerance is reasonably defined by giving the reduced amount of roller radius at three points so that the von Mises equivalent stress will not exceed a specified limit, where the point locations are not measured from the roller end but from the intersection of the crowning and the chamfer. For the purpose of design usefulness, the tolerance expression is offered in dimensionless form.

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This paper deals with position-based 6-DoF visual servoing. With a common sense of feedback control, we stress that improvement of the dynamics of the sensing unit is important for a stable visual servoing. We propose a method to improve dynamics in visual recognition, with compensating the fictional motion of the target in the camera images based on kinematics of the manipulator, by extracting the real motion of the target. We named it as hand-eye motion feedforword (MFF) method. The enhanced dynamics of recognition gave further stability and precision to the total visual servoing system, evaluated by full 6-DoF servoing experiment using 7-link manipulator. The convergence time in step response was about 10[s] and precise visual servoing to a moving target object has been achieved.

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As the track density of hard disk drives is increased, ways to suppress flow-induced vibration such as vibration of the disk and arm, are needed. For practical application, such countermeasures should not increase power consumption. We have developed a “window spoiler” with wings, each having a large hole and the same outer dimensions as an original spoiler. In experiments, the window and metamorphosed two-parallel-beam spoilers more effectively decreased the average downstream flow velocity than the original spoiler without holes thereby reducing the disk flutter by 8-10 %. This effect was due to increased drag occurring when there was sufficient distance between the two beams in a tandem arrangement.

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The shape of a nozzle for high-quality printing was optimized by using a standard, robust design method, and a method for fabricating the optimized nozzle was established. Several fabrication methods were tested, and the best fabrication method, which consists of three drilling steps and a punching step, was selected in terms of productivity, cost, and manufacturing accuracy. As for the shape-optimization process, eight parameters defining the shape of the nozzle were selected, and their influence on the stability of the driving voltage of the ink was evaluated. It was found that the length of the straight-line part in the exit part of the nozzle (defined as the “straight length” of the nozzle) is the most influential of the parameters. After this evaluation, to find the optimum fabrication condition a nozzle was fabricated by drilling and punching under various conditions. Under the optimum condition, it is possible to fabricate a nozzle with accuracy in diameter of 1 µm or less. According to the results of accelerated wear-out tests, it is forecast that the new nozzle can be used for more than 50,000 hours and meet its target usage lifetime.

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This work presents an approach for structural synthesis of ancient drawings which are illustrated uncleanly and with uncertain joints. Based on the structural analysis of the mechanism, the characteristics and design constrains of the drawings with uncertain joints are concluded. Then, according to the concepts of generalization and specialization subject to the concluded design constrains, all feasible structures of mechanism are reconstructed that meet the technological standards of the subjects’ time period. Three examples in book Tain Gong Kai Wu are provided to illustrate the proposed approach. And, this provides a logical foundation to deal with the issue for the ancient drawings with uncertain joints.

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The present paper considers optimization of lens adjustment in semiconductor lithography equipment. For improving productivity, the laser irradiation power of recent semiconductor lithography equipment has been boosted, which causes significant aberration due to heating during exposure. The aberration of the equipment must be measured or estimated in order to adjust the positions and orientations of the lenses. Since this adjustment is performed sequentially during exposure, the optimization problem to obtain optimal lens adjustment should be solved within a time as short as 100 ms. Although the problem of calculating the optimal lens adjustment can be naturally formulated as a convex minimization problem, in such a formulation the objective function is convex but includes several nondifferentiable points. Hence, optimization methods based on derivatives cannot be applied. Other approaches using derivative-free optimization or meta-heuristic methods cannot guarantee that the obtained solutions are truly optimal. Therefore, we formulate the optimization problem as quadratically constrained and second-order cone programming problems, which can be handled by solvers using an interior point method. Using the proposed formulations, computational experiments demonstrate that the optimal lens adjustment is obtained in a practical computational time, which is much less than 100 ms.

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