Yoshihiro Sakamoto

Synthesis of Multiple DOF Parallel Mechanism Satisfying Maximum Working Space.

In the present paper, a space-arrangement system of structural element for multiple degree-of freedom parallel mechanisms with consideration of mutual interferences among structural elements such as links and pairs is investigated. In order to determine optimum profiles of links which satisfy the maximum working space of the end effector, a rotary plane which is arbitrary fixed on one of the moving link in the mechansim is introduced, and rdative loci of intersection points of the other moving links with the plane are analyzed. Moreover, conditions to determine link arrangements avoiding mutual interferences of moving links are formulated. Applying the above-mentioned system, a spatial six-DOF parallel mechanism with consideration of interferences among moving links is synthesized as a practical example.

Synthesis of Conveying Machine Satisfying Minimum Number of Layers

In the design of a planar conveying machine, individual links must be arranged separately on parallel planes, which are called layers in this paper, to avoid mutual interference among moving links during a cycle of motion. In the present study regarding a planar 6-link conveying machine, conditions which determine the minimum number of layers required for constructing the conveying machine are formulated. Moreover, in order to determine the optimum profiles of links which satisfy the minimum number of layers to avoid mutual interference among moving links, relative loci of pairing points and positions of links on the same layer during a cycle of motion are analyzed. Based on the results of analysis the planar 6-link conveying machine satisfying minimum number of layers is synthesized.

Study on Type of Layer Arrangements of Planar Eight-Bar Mechanisms Satisfying Minimum Number of Layers.

In designing planar mechanisms, individual links constructing the mechanisms must be arranged separately on parallel planes to avoid mutual interference during a cycle of motion and the mechanisms have to be constructed in the smallest space possible. In this paper, as for planar eight-bar crank mechanisms with only revolute pairs, the layer arrangement with the minimum number of layers is determined taking the conditions of construction of mechanisms and the full rotation of pairs into consideration. Furthermore, the above-mentioned numbers are applied to classify the types of the eight-bar crank mechanisms which reveal the locations of moving planes of the links and pairs.

A synthesis of spatial mechanism with minimum moving space

In the present paper, a link-arrangement system for spatial mechanisms with consideration of mutual interferences among moving links is investigated. In order to determine optimum profiles of links which satisfy the minimum moving space of the mechanisms, a rotary plane which arbitrary fixed on one of the moving link in the mechanism is introduced, and relative loci of pairing points and positions of links with this plane are analyzed. Moreover, conditions to determine link arrangements avoiding mutual interferences of moving links are formulated. Based on the above analytical results, a link-arrangement system is constructed which obtains the optimum profiles and arrangements of links of spatial mechanisms. Applying the system, a spatial 4-bar mechanism is synthesized as a practical example.

A study on the balancing of the fluctuating input torque in the planar multi-link materials handling mechanisms.

In this paper, a dynamic analysis on the balancing of the fluctuating input torque in a planar multi-link conveying machine is carried out, as a practical example of an automatic conveying machine which generates an L-path. Namely a planar 12-link conveying machine is proposed, which is made by joining a slider-crank mechanism to the input link of the 9-link mechanism, for the purpose of neglecting the influences of the inertia force in the links. Moreover, optimum distributed masses and moments of inertia of the plural oscillating links are determined so as to reduce the fluctuation of the torque affecting input link. Based on the above analytical results, the dynamic characteristics of the machine are investigated theoretically and experimentally. As a result, it has been obvious that the maximum magnitudes of the torque affecting the input link reduce up to approximately one third the level of that which was measured at a state of unbalance. At the same time, the positioning accuracy of the machine hand at the edge points of the path can be greatly improved.