Mahmud Hasan Saikot

Perching has recently emerged as a key capability in aerial robotics, enabling substantial gains in energy efficiency and operational endurance for long-duration missions. In this work, we present a multifunctional perching mechanism capable of both branch and surface perching. For branch perching, the mechanism uses four simultaneously-actuated claws to grasp branches with diameters up to 35 mm. For surface perching, it leverages a bistable mechanism with five suction cups, allowing perching onto flat smooth surfaces with large orientation misalignment (with surface tilt angles of up to $\mathbf{80}^\circ$). The mechanism is fabricated using a combination of multimaterial 3D printing and silicone molding, resulting in a lightweight prototype with a mass of 32g. Experimental results show that the proposed design achieves $\bm{6.4\times }$ adhesion success compared to a bistable mechanism with a single suction cup. Furthermore, real-world perching experiments onto cars and tree branches demonstrate the effectiveness of the mechanism in different environments, highlighting its potential for energy-efficient and adaptable aerial robotic operations.

The present study explores the effect of using two porous deflectors on the performance of the Savonius wind turbine compared to only one porous deflector. The numerical simulation is performed to solve the unsteady Navier-Stokes equations using the SST k-

Braille is one of the most popular mediums of education for the blind. However, learning braille requires trainers and a lot of practice. Additionally, different individuals have different levels of tactile sensitivity at their fingertips. The tactile components get often overlooked in most braille learning devices and related studies. Our solution is a single cell refreshable braille display with six custom-made electromechanical flapper actuators. It incorporates speech functionalities to facilitate self-learning and independent operation. The cell size can be adjusted according to the learners preference by moving the actuators. The device can provide standard braille cell dimensions and elevation as well. It is designed to help learners with different tactile perceptions improve themselves through practice and adapt to standard size braille. The operational conditions and force analysis of the braille dots were performed. Two tests were also performed with two different cell sizes to evaluate the device with several blind students. The device is very affordable and easy to maintain. It can also be used to teach braille to the sighted.