In this paper, to achieve the goal of aiding the blind and visually impaired (BVI) to read any text not written in Braille, a custom-built, finger-wearable, and electro-tactile based Braille reading system with its Rapid Optical Character Recognition (R-OCR) method is developed. The R-OCR is capable of processing text information in real time using a miniature fish-eye imaging device mounted at the finger-wearable system. This allows real-time translation of printed text to electro-Braille along with natural movement of user's fingertip as if reading any Braille sign or book. An electro-tactile neuro-stimulation feedback mechanism is further proposed and incorporated with the reading system, which facilitates a new opto-electrotactile-feedback-based text line tracking control approach that enables text line following by user's fingertip during reading. Extensive experiments were designed and conducted to test the ability of blindfolded participants to read through and follow the printed text lines based on this optoelectrotactile-feedback method. The experimental results show that as the outcome of the opto-electrotactile-feedback, the users who involved in the feedback loop were able to maintain their fingertips within a$2mm$distance of the text while “reading” through a printed text line. Our work is a significant step to aid the BVI users with a portable means to read any printed texts to Braille through the following and the translation, whether in the digital realm or physically, on any surface.

This paper presents our comparative study on how the flight performances of an in-flight morphing quad-rotor are affected by the morph induced inertia variation. A custom-built in-flight morphing quad-rotor was employed in numerical and experimental tests for the study and analysis. In these tests, the quad-rotor is controlled to follow a predefined path and/or to hover in an environment with the constant wind disturbance. Our numerical results indicate that the morphing-size-down quad-rotor exhibits more agile in flight attributed to the compact volume/size, while the big-size one shows more flight stability in a disturbed and windy environment. Compared to regular scaled aerial vehicles whose volume/size changes follow a weight change proportionally, the numerical results reveal that our morphing quad-rotor that changes its volume with identical mass can acquire more merits towards high flight performances. Experimental validations further prove that through adaptatively transform its size in a complex and constrained environment, the in-flight morphing quad-rotor is not only capable of well performing path following tasks when encountering obstacles on the path or nearby the path, but also enhances the flight performance of withstanding external torques by extending its size so as to increase its moment-of-inertia. In summary, our in-flight morphing quad-rotor can acquire higher flight performances by adaptatively morphing when flying in complex environments.