This paper presents a novel design of MEMS logic gate that can perform Boolean algebra the same as logic devices that are composed of solid-state transistors. This MEMS logic gate design inherits all the advantages from MEMS switches and thus is expected to have more applications than MEMS switches. One unique feature of this device is that it can perform either NAND gate or NOR gate functions with the same mechanical structure but with different electrical interconnects. In a prototype design, the device is 250 µm long, 100 µm wide and has 1 µm gap. The experimental results show that this device can operate at 10/0 V and achieve the proposed logic functions. The resonant frequency of the device is measured roughly at 30 kHz. Due to no metal-to-metal contact in the current device, the logic functions of the design are verified through observations and video taping.
This paper presents the design, fabrication and calibration of a novel MEMS logic gate that can perform Boolean algebra as well as logic devices composed of solid-state transistors. Unlike existing designs, the proposed design can perform either NAND gate or NOR gate functions using the same mechanical structure, but different electrical interconnects. The proposed design imposes three requirements on the fabrication process: two voltage levels carried on a suspended plate, metal-to-metal contact between shuttle electrodes and fixed electrodes, and a low process temperature (<300 • C). To fulfill these requirements, the residual stress in the fabricated device is substantial which could impair the functionality of the device. Therefore, a novel in situ film stress calibration method is developed to assist the development of the fabrication process. In a prototype design, the fabricated device is 250 μm long, 100 μm wide and of 3.97 μm gap. Experimental results show that the device can operate at 25/−25 V and 100 Hz, and achieve the proposed logic functions. In addition, several properties of this device are experimentally evaluated, including power consumption, on/off resistance, lifetime and resonant frequency.
The capability of landing on previously unvisited areas is a fundamental challenge for an unmanned aerial vehicle (UAV). In this paper, we developed a vision-based motion estimation as an aid to improve landing performance. As an alternative to the common scenarios accompanying by external infrastructures or well-defined marker, the proposed hybrid framework can successfully land on a new area without any prior information about guiding marks. The implementation was based on the optical flow technique associated with a multi-scale strategy to overcome the decreasing field-of-view during the UAV descending. Compared with a commercial Global Positioning System (GPS) through a sequence of flight trials, the vision-aided scheme can effectively minimize the possible sensing error, thus, leading to a more accurate result. Moreover, this work has potential to integrate the fast-growing image learning process and yields more practical versatility for UAV applications in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.