This paper describes the design, fabrication, characterization, and satellite integration of a miniaturized two axis sun sensor which has been used in the attitude control system of the Spanish nano-satellite NANOSAT-1B. This device is made of four silicon photodiodes monolithically integrated in a crystalline silicon substrate, protected by a transparent cover glass assembled on the same silicon die against space radiation damage. The sensor fabrication combines standard silicon processing technology with a high performance solar cell fabrication process. The sensor, including electronics and mechanical and electrical interfacing with the satellite, has a small size (3 cm × 3 cm) and low weight (24 gr.), with a sun field-of-view greater than ±60° with an angle accuracy better than 0.15°. Three of these sensors have already been integrated in the NANOSAT-1B platform that has been successfully launched in July 2009.
1 January 1996 in IEEE Transactions on Signal Processing
Use of advanced communication technologies, highly integrated control, and programming platforms drastically increases the performance of industrial control systems. That is the case of Motronic, where the synergistic collaboration between industry and academia has led to an advanced distributed network control system. To be commercially successful, it needs to have a low cost and to be robust, even if this requirement implies that it is a custom design and not based on previously existing commercial solutions. Use of standards and off-the-shelf products lower development costs, but usually raise production costs. In this paper, we show that, in certain applications, design of a new system from scratch is more advantageous. This system comprises a set of dynamically reconfigurable local controller nodes, a graphical programming environment, a remote supervision and control system, and a fault-tolerant fiber optical network. TCP/IP connectivity is provided by the use of a local gateway. Motronic is currently being applied in the integrated control of large production plants and in energy and power management industries.
Among the different pulse codification techniques, stochastic pulse codification has its own arithmetic based on the similarity between Boolean algebra and statistical algebra. Summation and multiplication are the two basic arithmetic operations treated in depth in the literature. In this paper we present two digital stochastic circuits that extend traditional stochastic algebra: a division circuit and a square-root circuit, and the interfaces between the analog and stochastic domain. As a result, we are able to process analog input signals with a simple and complete processing system. These circuits can be implemented in low-cost and low-power digital programmable devices.
24 February 2012 in IEEE Transactions on Industrial Electronics
This paper describes the design, fabrication, simulation, and experimental results of an improved miniaturized two-axis sun sensor for industrial applications, created by adapting a technology used previously in satellite applications. The sensor for each axis is composed of six photodiodes integrated in a crystalline-silicon substrate and a layer of cover glass, which is used to protect the silicon and to hold the windows. The high precision is obtained by the subdivision of the field of view, which is ±60°, with a resolution of 0.1°. Each region is controlled by an independent high-precision solar sensor. The sensor can be used for sun-tracking applications in a photovoltaic system, heliostat concentration plants, and lighting applications.
This paper describes the fabrication opportunities that Printed Circuit Boards (PCBs) offer for electronic and biomedical engineering. Historically, PCB substrates have been used to support the components of the electronic devices, linking them using copper lines, and providing input and output pads to connect the rest of the system. In addition, this kind of substrate is an emerging material for biomedical engineering thanks to its many interesting characteristics, such as its commercial availability at a low cost with very good tolerance and versatility, due to its multilayer characteristics; that is, the possibility of using several metals and substrate layers. The alternative uses of copper, gold, Flame Retardant 4 (FR4) and silver layers, together with the use of vias, solder masks and a rigid and flexible substrate, are noted. Among other uses, these characteristics have been using to develop many sensors, biosensors and actuators, and PCB-based lab-on chips; for example, deoxyribonucleic acid (DNA) amplification devices for Polymerase Chain Reaction (PCR). In addition, several applications of these devices are going to be noted in this paper, and two tables summarizing the layers’ functions are included in the discussion: the first one for metallic layers, and the second one for the vias, solder mask, flexible and rigid substrate functions.