竹原 昭一郎

In the present paper, the motion of a tethered system with large deformation and large displacement is discussed. In general, a tether is a cable or a wire rope, and a tethered system consists of a tether and the equipment attached to the tether. A tethered subsatellite in space is an example of a tethered system. In the present study, a tethered system consisting of a very flexible body (the tether) and a rigid body at one end is considered as the analytical model. A flexible body in planer motion is described using the Absolute Nodal Coordinate Formulation. Using this formulation, the motion of a flexible body with large deformation, rotation and translation can be expressed with the accuracy of rigid body motion. The combination of the flexible body motion and the rigid body motion is performed, and their interaction is discussed.<br>Experiments are performed to investigate the fundamental motion of the tethered system and to evaluate the validity of the numerical formulation. Experiments were conducted using a steel tether and a rubber tether in gravity space. In addition, an experiment of the motion of the tethered system with a rigid body in microgravity space was conducted.

This study is focused on dynamic behavior of a small size tire. A small size tire is used for personal mobility, for example, a bicycle, a wheelchair and so on. We made experiments device for vertical behavior on bump for small size tire. We performed experiments to investigate the vertical behavior on bump for small size tire. We measured the force, the acceleration acting on tire and the vertical displacement of tire.

In this paper, the dynamic characteristics of a small wheel bicycle are discussed. In the dynamic analysis with multibody dynamics, the influence of the head angle on the small wheel bicycle is investigated. With the driving experiment of the small wheel bicycle, straight-ahead stability and upstanding stability are evaluated by the subjects and measured by the experimental apparatuses. The results show the smaller head angle has more stability and the results are corresponding with the simulation results.

In this study, the modeling and formulation for tether motion with time-varying length, large rotation, large displacement and large deformation are proposed. A tether or cable is an important element in lift systems, construction machines for transportation and often is used with a time-varying length. In some cases, these systems are large and the tether has a long length, large deformation and large displacement. The dynamic behavior of a tether in extension and retraction using the proposed method is discussed in this paper. In the passage through resonance, significant tether motions with large rotation and large deformation result. In the analysis of this phenomenon, the transient fluctuations of the motion amplitudes are examined and compared with the corresponding steady state motions. The accuracy and the cost of the calculations are also verified by comparison with the experimental results.