Hideyuki Ohtaki

Poisson's Ratio and Elastic Modulus of Honeycombs for a Large Deflection Model

We have developed a theoretical model for predicting the in-plane mechanical properties of honeycombs based on the large deflection of the inclined and vertical members of the honeycomb cells. We have used the large deflection approach for a segment including honeycomb cells. Then we derive expressions for Elastic modulus and Poissons ratios in two orthogonal directions, and the shear modulus of honeycombs. Elastic modulus, Poissons ratios and the shear modulus of honeycombs are expressed using incomplete elliptic integrals. The results show that these mechanical properties are no longer constant at large deflections but vary significantly with the strain

The Stress Distribution of an Ellipsoidal Gear.

The higher accuracy and better quality are required on the gear drives ; Its necessary to study the strength and profile of ellipsoidal gear which is predicted to be used widely in the future. However the stress distribution and deformation of the gears teeth when a load is applied to the boundary have not been extensively analyzed. In this study, the stress distribution and deformation of an ellipsoidal gears teeth is analyzed using a complex stress function. This method makes it possible to obtain any ellipsoidal gears profile using a mapping function and to analyze the stress distribution and deformation correctly and easily using above mentioned stress function.

Movement Control of a Small Jumping Machine.

We have developed a small jumping machine. For such machines, it is difficult to control the direction and velocity of motion by using conventional control devices, since there is not sufficient space to install them. Therefore we must develop another suitable control method. In this report, we investigate the following and movement control method of a small jumping target and elucidate its performance by analyzing graphical data extracted using a CCD camera. We propose a method of creating a virtual eye on the computer display, with which to follow a target. Moreover, we propose a controling method of jumping direction and velocity.

Structures Which Support the Parabolic Structural Surface.

Structures which can be modified to make fine adjustments to arbitrary structural surfaces have been investigated in the construction of space structures. Considering the geometrical configuration of these structures, the. same concept might be applied to structures such as those which are used in collecting sunlight. In this paper, we describe a designing method by which to build to build structures that can be extended and adapted to a parabolic structural surface.

Analysis of Dynamic Behaviour for a Lead Screw-Type Positioning System Using Linear Graph Theory. Transient Response Analysis of Feedback Control System and Reduction of Positioning Time.

Recently, the fine positioning system has been used in the mechanical industry, and has required the improvement of positioning accuracy, reduction of positioning time, increase of carrying capacity and so on. However, the existing control method for the positioning stage may cause delay of phase response or residual vibration when disturbance or overweight acts on the system or stage drives at high speed. In order to obtain the optimum control inputs, it is necessary to grasp the dynamic behaviour of the system precisely. First, this paper deals with the transient response of the positioning stage using the linear graph theory reported in the previous papers. The simulated results of transient response of the positioning stage are compared with the experimental ones, and they are found to be in good agreement. Next, a procedure which can reduce the settling time of positioning is proposed by utilizing this method. As a result, this procedure was able to reduce the settling time by 55%, as compared with only proportional control.

Analysis of dynamic behaviour for power transmission mechanism using linear graph theory

The importance of system design in the field of mechanical engineering has been increasingly recognized, but suitable and useful methods for machine design are not yet established. The authors derive easy and useful designing methods for each machine element. They derived a new designing method by linear graph theory and analyzed the results of the dynamic behavior of a power transmission mechanism as an example. The mechanisms which are subject to restrictions of high accuracy and high performance must be designed by considering the characteristic of each machine element. This report deals with a more general power transmission mechanism containing a motor, bearing, and support, and analyzes the results of dynamic behavior. Provided that the analytical model and system graph as in this report are prepared for the mechanism, the performance of the mechanism is easily grasped by this method.