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In this paper, collision-free guidance control of multiple small unmanned aerial vehicles (SUAVs) is designed. Collision avoidance of the SUAVs should be considered in the control system design for safe operation. Therefore, a guidance control system using a distributed model predictive control (DMPC) is proposed to realize the collision avoidance. A constraint for the relative position vector between the each UAV is considered in the design for efficient avoidance. Small multi-rotor helicopter is considered as controlled object, and the guidance control system is designed by using the translational model of the helicopter. DMPC is designed with three constraints, an input constraint, a state constraint, and a relative position vector constraint. An input constraint and a state constraint realize collision avoidance in input within the constant limits. If the moving path of the one helicopter is significantly affected by the moving path of other helicopter, the relative position vector constraint makes the helicopters exchange their relative position each other. By using these constraints, smooth collision avoidance is realized. The numerical simulation and flight experiment is conducted to verify the effectiveness of designed control system.

Since linear fracture mechanics was proposed by Irwin in 1957, its usefulness has been recognized widely. However, there is no detailed discussion about the range of applicability of linear fracture mechanics (Linear Crack Mechanics). Originally, linear fracture mechanics should be called linear crack mechanics. Recently, non-linear crack mechanics was proposed by one of the authors and its usefulness was confirmed though the analysis on the limited numbers of geometrical conditions. Considering these facts, first the effectiveness of non-linear crack mechanics is confirmed by FEM analysis on a wide range of geometrical conditions. Then, the effective range of linear fracture mechanics is discussed based on non-linear crack mechanics, taking as examples the cases of a strip with a center crack and a strip with two edge cracks under tension.

FEM is a very powerful method for stress analysis. However, it is still not necessarily easy to obtain the highly accurate values of stress intensity factors or stress concentration factors by FEM. Recently, authors have proposed the non-linear crack mechanics which use the values of strain at a crack tip. In this paper, a method for calculating the highly accurate values of K1 or Kt by FEM is proposed, based on the usefulness of the stress values at a crack tip or a notch root obtained by FEM.

This paper analyzes the contact pressure distribution and the elastic deformation of a blanket in offset printing due to a contact force of the impression (or plate) cylinder with the blanket cylinder, considering anisotropic properties and the laminated construction of the blanket. The two dimensional elastic theory is applied to solve the contact problem of the blanket and the numerical solution provides details of the contact pressure distribution, the deformation of the blanket surface, and the contact width of the blanket with the impression (or plate) cylinder. Influences of Young's moduli and thickness of each layer of the blanket on the contact pressure distribution and the deformation of the blanket surface, are examined by the theory in detail. To prove the validity of the theory, experiments are carried out using the device developed to measure the contact pressure distribution and the deformation of the blanket. The calculated results are in good agreement with those of experiment.

A basic theory of the space belt mechanism that changes coin attitude from horizontal to vertical is proposed. The coin is transferred along the space curve line of the belt being pressed tightly against the curved surface of the solid guide block. The differenitial equations governing the space belt curve were derived for an arbitrary given guide block surface with arbitrary inlet and outlet positions of the coin. Theoretical analysis proved that the component of inertia force of the belt perpendicalar to the belt surface and parallel to the block surface was zero. The theoretical results and those of corresponding experiment for the bending/twisting ruled surface were compared and confirmed the validity of the theory. The analytical method to examine the separation of the belt from the guide surface was also proposed.