Lure fishing and fly-fishing have been positioned as sports deliberately different from the traditional Japanese fishing-style. In the case of fly-fishing, casting is the element which anglers must master to cast a fly, done so by using the weight of a line. This study uses experimental and computational analysis to investigate the dynamic behavior of a fly line. Fly-fishing is constituted by various elements, but the importance that casting holds is extremely large. Flying speed, the casting process, and the loop shape of the line while in flight are important for the proper presentation of flies. Moreover, the shape of a fly line is also important for a long cast or controlled cast. Therefore, the most suitable casting method will be clarified from the viewpoint of sports engineering and human dynamics. There are some types of casting techniques, overhead cast, side cast, false cast (forward cast and back cast), double haul cast and roll cast. Fly casting has an aspect that is one of the means to place lightweight objects in places that are difficult for humans to reach using flexible strings. The lightweight objects are expected to be applied to transport in a wide range of spaces by constructing a casting system. Therefore, this study focuses on the constructing a casting system with reference to fly casting. In the past studies, fly casting was not applied to transport. Only the flight shape of the line was focused on. In this study, a two-link casting system that reproduces the movements of the human forearm and wrist is created. The possibility of that the system can transport lightweight objects in forward casting would be shown.
It is known that chatter marks are formed on the machined surface when chatter vibration occurs during cutting. This paper proposes a method for inverse analysis of the frequency and phase difference of chatter vibration during cutting based on the periodicity of the chatter mark on circular machined surface analyzed by the two-dimensional discrete Fourier transform. The chatter mark on the circular machined surface was reconstructed on the image by projecting multiple images taken by a digital camera of the machined surface onto the circular machined surface on the computer, based on the camera calibration using the accurate table feed of the machine tool. The chatter vibration information, which was obtained by the proposed method based on the two-dimensional discrete Fourier transform of this reconstructed chatter mark image, was compared with the information analyzed from the tool displacement during cutting. As a result, the proposed process is found to be effective as an inverse analysis method to estimate the chatter vibration when end milling the curved surface.