Dynamic Analysis of the Locomotion Mechanism in Foxtail Robots: Frictional Anisotropy and Bristle Diversity.

This study investigated the locomotion mechanism of foxtail robots, focusing on the frictional anisotropy of tilted bristles under the same friction coefficient and propulsion strategy using bristle diversity. Through dynamic analysis and simulations, we confirmed the frictional anisotropy of tilted bristles and elucidated the role of bristle diversity in generating propulsive force. The interaction between contact nonuniformity and frictional anisotropy was identified as the core principle enabling foxtail locomotion. Simulations of foxtail robots with multiple bristles demonstrated that variations in bristle length, angle, and deformation contribute to propulsive force generation and environmental adaptability. In addition, this study analyzed the influence of major design parameters on frictional anisotropy, highlighting the critical roles of body height, bristle length, stiffness, reference angle, and friction coefficient. The proposed guidelines for designing foxtail robots emphasize securing bristle nonuniformity and inducing contact nonuniformity. The simulation framework presented enables the quantitative prediction and optimization of foxtail robot performance. This research provides valuable insights into foxtail robot locomotion and lays a foundation for the development of efficient and adaptive next-generation robots for diverse environments.

Speckle noise reduction for digital holographic images using multi-scale convolutional neural networks.

In this Letter, we propose a fast speckle noise reduction method with only a single reconstructed image based on convolutional neural networks. The proposed network has multi-sized kernels that can capture the speckle noise component effectively from digital holographic images. For robust noise reduction performance, the network is trained with a large noisy image dataset that has object-dependent noise and a wide range of noise levels. The experimental results show the fast, robust, and outstanding speckle noise reduction performance of the proposed approach.

Increasing the storage density of a page-based holographic data storage system by image upscaling using the PSF of the Nyquist aperture.

We introduce an image upscaling method that reduces bit errors caused by Nyquist apertures. Nyquist apertures used for higher storage densities generate optical aberrations and degrade the quality of the image that is recorded on the medium. Here, to correct the bit errors caused by the Nyquist aperture, an image upscaling method is used to restore the degraded image in the enhanced spatial frequency domain using its point spread function (PSF) as a restoration filter. The proposed method reduces the bit error rate (BER) significantly and hence allows higher storage densities.

Walking and sit-to-stand support system for elderly and disabled.

Walking and sit-to-stand support system, the smart mobile walker, is being developed to help elderly and disabled to live an independent daily life. It comprises almost omnidirectional driving mechanism, sit-to-stand support mechanism, and motion compliance module to control the system. The development and evaluation of basic motion compliance algorithm shows that the algorithm for extraction of user intention from the interaction of the operator and the system determines performance of the system. The required parameters and performance index for improving sit-to-stand function are evaluated by the analysis of force reflection between the operator and the system. Finally, future research topics to improve the performance are addressed.

Kinematic analysis of sit-to-stand assistive device for the elderly and disabled.

This paper introduces a robotic walking and sit-to-stand support system, Smart Mobile Walker(SMW), and presents kinematic analysis of the system. For supporting person's sit-to-stand movement, the motion of SMW is modeled by the analysis of kinematics. The results of analysis are used for simulations and its feasibility is investigated by simulations. The feasibility shows our analysis of kinematics can be applied as a base of making optimal motion trajectory for helping sit-to-stand.