Tuna Balkan

Bio: Tuna Balkan is an academic researcher from Middle East Technical University. The author has contributed to research in topics: Kinematics & Inverse kinematics. The author has an hindex of 15, co-authored 39 publications receiving 1017 citations.

An electromagnetic micro power generator for wideband environmental vibrations

Abstract: This paper presents a wideband electromagnetic vibration-to-electrical micro power generator. The micro generator is capable of generating steady power over a predetermined frequency range. Power is generated by means of the relative motion between a magnet and coils fabricated over resonating cantilevers through electromagnetic induction. The reported generator covers a wide band of external vibration frequency by implementing a number of serially connected cantilevers in different lengths resulting in an array of cantilevers with varying natural frequencies. The device generates 0.4 μW of continuous power with 10 mV voltage in an external vibration frequency range of 4.2–5 kHz, covering a band of 800 Hz.

An Electromagnetic Micro Power Generator for Low Frequency Environmental Vibrations based on the Frequency Up-Conversion Technique

Abstract: This paper presents a microelectromechanical-system-based electromagnetic vibration-to-electrical power generator that can harvest energy from low-frequency external vibrations. The efficiency of vibration-based harvesters is proportional to excitation frequency, so the proposed generator is designed to convert low-frequency environmental vibrations to a higher frequency by employing the frequency upconversion (FupC) technique. It has been shown that the generator can effectively harvest energy from environmental vibrations of 70-150 Hz and generates 0.57-mV voltage with 0.25-nW power from a single cantilever by upconverting the input vibration frequency of 95 Hz-2 kHz. The fabricated generator size is 8.5×7×2.5 mm3, and a total of 20 serially connected cantilevers have been used to multiply the generated voltage and power. The generator demonstrated in this paper is designed for the proof of concept, and the power and voltage levels can further be increased by increasing the number of cantilevers or coil turns. The performance of the generator is also compared with that of a same sized custom-made traditional magnet-coil-type generator and with that of a traditional generator from the literature to prove its effectiveness.

Process modeling, simulation, and paint thickness measurement for robotic spray painting

Abstract: An algorithm and a computer program are developed for modeling of the spray painting process, simulation of robotic spray painting, and off-line programming of industrial robots for painting of curved surfaces. The computer program enables the user to determine the painting strategies, parameters, and paths which will give the desired paint thickness. Surface models of the parts that are to be painted are obtained by using a computer-assisted design (CAS) software. Models of relatively simple surfaces are formed by using the surface generation tools of the CAD software. For parts with more complex surfaces, point data related to the part is collected by using a laser scanner, and this data is used to form the CAD model of the part surface. The surface is then divided into small triangular elements and centroid coordinates, and unit normals of the elements are determined. Surface data together with the spray distance, painting velocity, and paint flow rate flux are used for simulation of the process and paint thickness analysis. Paint flow rate flux is determined experimentally by using different spray gun settings and painting parameters. During the experiments flat surfaces are painted by using a single painting stroke of the gun. Then, paint thickness measurements are made on the surfaces. It is observed that besides the technical specifications of the spray gun, air and paint nozzles, and paint needle, basic settings like paint tank pressure, spray air pressure, and gun needle-valve position affect paint cone angle and paint flow rate, which finally characterize the spray painting process. For that reason, settings and parameters should be changed and the painting process should be simulated until an acceptable paint thickness distribution is obtained for the part that is going to be painted. The robot program is then generated in the robot's programming language. Paint thickness distribution on the painted surface is determined by measuring the thicknesses using the robot and the CAD model of the part surface. The thicknesses are measured at the centroids of the surface elements. A measurement probe of the coating thickness measurement gauge is attached to the wrist of the robot by using a feedback/safety adapter designed and manufactured for this purpose. © 2000 John Wiley & Sons, Inc.

An electromagnetic micro energy harvester based on an array of parylene cantilevers

Abstract: This paper presents the design, optimization and implementation of an electromagnetic type vibration-to-electrical micro energy harvester. The proposed harvester implements a new design employing array of parylene cantilevers on which planar gold coils are fabricated. The micro harvester generates voltage by virtue of the relative motion between the coils and a stationary magnet. The coils are connected electrically in series to sum up the voltage output from individual cantilevers. The number of cantilevers can be adjusted to improve the generated power without significantly increasing the overall device volume. Another forthcoming feature of this study is the investigation of the phase-shift phenomenon, which is the effect of natural frequency mismatches between the cantilevers due to fabrication related nonuniformities. A detailed mathematical modeling and optimization of the design for various cases, together with the phase and frequency shifts between the cantilevers, are carried out. The proposed harvester is implemented on a microscale and mathematical modeling is verified through extensive tests. The fabricated device occupies a volume of 9.5 × 8 × 6 mm3. A single cantilever of this device can generate a maximum voltage and power of 0.67 mV and 56 pW, respectively, at a vibration frequency of 3.4 kHz. These values can be improved considerably by increasing the coil turns and natural frequency of the cantilevers. However, our test results show that any mismatch between the series cantilevers results in significant degradation of the overall output.

A Wideband Electromagnetic Micro Power Generator for Wireless Microsystems

Abstract: This paper presents a wideband electromagnetic (EM) vibration-to-electrical power generator which can efficiently scavenge energy and generate steady power over a predetermined frequency range. Power is generated by means of electromagnetic induction using a magnet and coils on top of resonating cantilever beams. The reported generator covers a wide band of external vibration frequency by implementing a number of serially connected cantilevers in different lengths. The device generates 0.5 muW continuous power with 20 mV voltage between 3.3 and 3.6 kHz of external vibration.

Toward large-scale energy harvesting by a nanoparticle-enhanced triboelectric nanogenerator.

Abstract: This article describes a simple, cost-effective, and scalable approach to fabricate a triboelectric nanogenerator (NG) with ultrahigh electric output. Triggered by commonly available ambient mechanical energy such as human footfalls, a NG with size smaller than a human palm can generate maximum short-circuit current of 2 mA, delivering instantaneous power output of 1.2 W to external load. The power output corresponds to an area power density of 313 W/m2 and a volume power density of 54 268 W/m3 at an open-circuit voltage of ∼1200 V. An energy conversion efficiency of 14.9% has been achieved. The power was capable of instantaneously lighting up as many as 600 multicolor commercial LED bulbs. The record high power output for the NG is attributed to optimized structure, proper materials selection and nanoscale surface modification. This work demonstrated the practicability of using NG to harvest large-scale mechanical energy, such as footsteps, rolling wheels, wind power, and ocean waves.

Freestanding triboelectric-layer-based nanogenerators for harvesting energy from a moving object or human motion in contact and non-contact modes.

Abstract: For versatile mechanical energy harvesting from arbitrary moving objects such as humans, a new mode of triboelectric nanogenerator is developed based on the sliding of a freestanding triboelectric-layer between two stationary electrodes on the same plane. With two electrodes alternatively approached by the tribo-charges on the sliding layer, electricity is effectively generated due to electrostatic induction. A unique feature of this nanogenerator is that it can operate in non-contact sliding mode, which greatly increases the lifetime and the efficiency of such devices.

Toward Broadband Vibration-based Energy Harvesting

Abstract: The dramatic reduction in power consumption of current integrated circuits has evoked great research interests in harvesting ambient energy, such as vibrations, as a potential power supply for electronic devices to avoid battery replacement. Currently, most vibration-based energy harvesters are designed as linear resonators to achieve optimal performance by matching their resonance frequencies with the ambient excitation frequencies a priori. However, a slight shift of the excitation frequency will cause a dramatic reduction in performance. Unfortunately, in the vast majority of practical cases, the ambient vibrations are frequency-varying or totally random with energy distributed over a wide frequency spectrum. Hence, developing techniques to increase the bandwidth of vibration-based energy harvesters has become the next important problem in energy harvesting. This article reviews the advances made in the past few years on this issue. The broadband vibration-based energy harvesting solutions, covering re...

Energy Harvesting for Autonomous Wireless Sensor Networks

Abstract: Wireless sensor nodes (WSNs) are employed today in many different application areas, ranging from health and lifestyle to automotive, smart building, predictive maintenance (e.g., of machines and infrastructure), and active RFID tags. Currently these devices have limited lifetimes, however, since they require significant operating power. The typical power requirements of some current portable devices, including a body sensor network, are shown in Figure 1.