Baby carriage vibrations cause unpleasant sensations for both the babies and carriage operators. This study analyzed the baby carriage vibration generated by passing over a level difference on a road surface because this situation introduces a large physical burden and significant stress. The purpose of this study is to develop simulation models in order to improve the performances of baby carriages under operating conditions efficiently. Furthermore, experiments were conducted using a real baby carriage to verify the accuracy of the simulation models. We focused on vibrations in the front leg because characteristic vibrations were generated in this part. Baby carriage models, such as the rigid body model (modeled as a rigid body other than the elastic deformation of suspension) and the elastic connection model (modeled the movement of joints around the legs), have been developed. However, the accuracy of these models are insufficient because these are not able to model highfrequency vibrations and the trend in the vibration peaks when the baby carriage passes over the level difference. Additionally, we developed the front leg elastic body model considered the elastic deformation of front legs based on the finite segment method. In the front leg elastic body model, front legs were divided into fifths, which were connected by translational and rotational springs because the time is required for analysis using the general finite element method. This model was able to provide the trend similar to the experimental result. Finally, the vibration reduction design for a baby carriage was considered by using the developed simulation model.
Human movement data can contribute to the quality improvement of industrial and medical products affected by such movement. Such data can be used to improve the quality of industrial products as well as in healthcare applications, such as the development of artificial joints. To develop and design artificial joints with enhance durability, it is necessary to set up standards of durability using human movement data in daily life. The aim of this study is to obtain data that contributes to the improvement in durability of artificial elbow joints. We have developed a wearable device that can measure its self-acceleration, angular velocity, and quaternions to collect human movement data continuously for long-term. Additionally, we collected the arm movement data of 30 participants using the developed device. The participants of this study carried on with their normal lives with the measuring device worn on their wrist. This study calculated the posture of the wrist over time using quaternions and mainly analyzed posture changes. We clarified the characteristics and trends of the movement of bending the elbow in daily human life.
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