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1
Content available remote Influence of modulation frequency on the synthesis of thin films in pulsed magnetron sputtering processes
Strzelecki G. W., Nowakowska-Langier K., Chodun R., Okrasa S., Wicher B., Zdunek K.
Materials Science Poland
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2018
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Vol. 36, No. 4
697--703
EN
The research on the influence of modulation frequency on the properties of films synthesized using a unique pulsed power supply combined with a standard unbalanced circular magnetron was conducted in the process of pulsed magnetron sputtering (PMS). It was shown that by using different levels of modulation, the composition of plasma (measured by optical emission spectroscopy, OES) as well as film growth rate and morphology (observed with scanning electron microscope, SEM), can be changed. The impact of modulation is related to the used materials and gases and can vary significantly. It was concluded that modulation frequency can greatly influence the synthesis of materials and can be used as an additional parameter in PMS. Specific relations between modulation frequency and synthesized material require further investigation.
2
Content available Konstrukcja i sterowanie trójkołowego roweru elektrycznego bez przekładni mechanicznej
Brock S., Fabiański B., Wicher B., Zawirski K.
Maszyny Elektryczne : zeszyty problemowe
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2018
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Nr 2 (118)
185--190
PL
W pracy przedstawiono konstrukcję prototypu oryginalnego trójkołowego pojazdu napędzanego pedałami ze wspomaganiem elektrycznym, bez sprzężenia mechanicznego korby pedałów z kołami. Każde z kół pojazdu jest napędzane przez bezszczotkowy silnik elektryczny (BLDC). Pedały napędzają generator, który ładuje baterię akumulatorów. Zaprojektowany został układ dystrybucji energii, zapewniający bezpieczne zachowanie się napędów pojazdu w warunkach awaryjnych. Zaprojektowane i zbudowane zostały centralny układ sterowania oraz dedykowane przekształtniki energoelektroniczne, a całość komunikacji odbywa się z wykorzystaniem protokołu CAN-open. Jako jednostkę sterującą zastosowano układ STM32F407, który pełni rolę sterownika we wszystkich podsystemach pojazdu. Prędkość pojazdu jest proporcjonalna, z nastawianym współczynnikiem, do prędkości pedałowania, natomiast moc dostarczana do silników poszczególnych kół jest odpowiednio większa od mocy generowanej przez rowerzystę. Dużą uwagę zwrócono na ergonomiczne właściwości układu napędowego, dopasowując charakterystykę momentu oporowego generatora do naturalnej charakterystyki pedałowania. W ten sposób układ napędowy zachowuje się analogicznie do klasycznego roweru mechanicznego.
EN
The paper presents the construction of a prototype of an original three-wheeled electrically powered vehicle. The vehicle is driven by pedals without mechanical coupling of the crank handle with the wheels. Each of the vehicles wheels is driven by a brushless electric motor (BLDC). The pedals drive a generat or that charges the battery. The power distribution system has been designed to ensure the safe behaviour of the vehicle's drives under emergency conditions. The central control system and dedicated power electronic converters have been designed and built, and all communicationis performed using the CAN-open protocol. STM32F407 is used as the control unit for all subsystems. Thespeed of the vehicle is proportional to the pedalling speed, with a variable factor, and the power supplied to the motors of the individual wheels is correspondingly higher than the cycling power. Considerable attention was paid to the ergonomic characteristics of the drive unit, adjusting the torque characteristics of the generator to the natural characteristics of the pedal system. In this way, the drive system behaves similarly to a classic mechanical bike.
3
Content available Structure and Electrical Resistivity Dependence of Molybdenum Thin Films Deposited by DC Modulated Pulsed Magnetron Sputtering
Wicher B., Chodun R., Nowakowska-Langier K., Okrasa S., Król K., Minikayev R., Strzelecki G., Zdunek K.
Archives of Metallurgy and Materials
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2018
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Vol. 63, iss. 3
1339--1344
EN
This work reports the results of a study of Mo thin films synthesis by DC Pulsed Magnetron Sputtering method (PMS), operating at pulse main frequency of 100 kHz and modulated by the additional modulation frequency, driving in the range of 5-1000 Hz (modulated Pulse Magnetron Sputtering – mPMS). We have studied the influence of mPMS on plasma chemical reactions and mechanisms of layer growth using optical emission spectroscopy technique. Our experiment showed strong influence of mPMS method, on the morphology (scanning electron microscopy), phase composition (X-ray diffractometry) and electric properties (4-point probes method) of nanocrystalline and amorphous Mo films. From the utilitarian point of view, low value of resistivity – 43,2 μΩcm of synthesized Mo films predestines them as back contacts for thin solar cells CIGS. Our results revealed that additional modulation frequency should be considered as an important factor for optimization of films synthesis by means of PMS-based methods.
4
Content available remote Multi-sided metallization of textile fibres by using magnetron system with grounded cathode
Chodun R., Wicher B., Skowroński Ł., Nowakowska-Langier K., Okrasa S., Grabowski A., Minikayev R., Zdunek K.
Materials Science Poland
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2017
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Vol. 35, No. 3
639--646
EN
The synthesis of coatings on textiles fibers enables functionalization of their properties e.g.: changing the reaction on IR radiation. In our experiment, a magnetron with a grounded cathode and positively biased anode was used as a source of plasma. A ring anode was positioned at 8 cm distance from the cathode. Samples of glass and cotton textile were placed at the plane of the anode. Ti and TiN coatings were deposited by sputtering of titanium target in Ar or Ar+ N2 atmosphere. SEM studies showed that, using the magnetron system described above, the textile fibers were covered by the 2 μm to 3 μm thick coatings. Unexpectedly, the coatings were deposited at both sides of the samples: the front side was exposed to glow discharge plasma and the backside was completely shaded from the plasma. IR optical investigation exhibited significant change in reflectance and transmittance of the coated textiles. The using of standard magnetron system (grounded anode and cathode at negative potential) resulted in a coating deposition at the textile side exposed to the plasma action only. We believe that the multi-sided deposition of coatings observed during the process run with magnetron with grounded cathode is a result of an ambipolar diffusion mechanism in the anodic potential drop region.
5
Content available The system of streaming and analysis of signals from MEMS accelerometers
Fabiański B., Nowopolski K., Wicher B.
Poznan University of Technology Academic Journals. Electrical Engineering
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2016
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No. 87
301--312
EN
In the article, a dedicated testing environment for MEMS acceleration sensors is shown. The system is able to collect data from multiple devices with different physical interfaces, send them through parallel streaming, archive, and analyze it. The architecture and operational algorithms of individual components, such as complex synchronization methods in the data streaming process is described. This data streaming is finally realized by Ethernet interface which becomes a bridge between the PC system running the dedicated application and the sensor board. In the last section of the article, quality indicators of acceleration sensors signals are presented. These indicators indicate primarily a useful signal to noise ratio with respect to the measurement resolution.
6
Content available Selected algorithms of MEMS accelerometers signal processing in burglary detector application
Fabiański B., Nowopolski K., Wicher B.
Poznan University of Technology Academic Journals. Electrical Engineering
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2016
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No. 87
267--278
EN
In the paper, implementations and results of operation of artificial neural network applied as a burglary classifier are presented in comparison to solution with a direct digital signal processing (DSP) approach. The neural network operates in a mobile access control device, that may be easily attached to a door. The device is an integrated system, equipped with several sensors based on microelectromechanical systems (MEMS) technology. Due to limited effectiveness of simple, conditional logic algorithms on acquired signal samples, a more sophisticated approaches are investigated. Data acquisition during imitation of various burglary scenarios and further processing of the recorded signals are described in the paper. Selection of the neural network structure and pre-processing methods of sensor signals are presented as well. The direct DSP algorithm based on the application of the properties of application phenomena is shown in the same way. Finally, results of selected algorithms implementation in a low-power 32-bit microcontroller system are presented. Limitation of the platform responsiveness in the real-time conditions and comparison of used classification methods are discussed in the paper conclusions.
7
Content available Control system in electric tricycle focused on high dynamics of pedals load torque response
Fabiański B., Wicher B.
Poznan University of Technology Academic Journals. Electrical Engineering
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2016
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No. 85
233--244
EN
In the article two different control system structures of electric driven tricycle are presented. The very specific feature of the vehicle is that it works with "pedaling by wire". It means, that there is no mechanical coupling between pedals and any of driven wheels. This structure gives an advantage of achieving wide range of the correlation between the pedals load torque and speed and the driven wheels electromagnetic torque and speed. The challenge is to provide a natural pedaling feels for the rider. Two different approaches for control system signal flow are compared for natural pedaling feel for cyclist. The system architecture bases on CAN network distributed control that links three independent wheel drives, dedicated HMI panel, generator inverter and centralized supervisory board. The modelling methods are presented in the paper with an appropriate analytical base. Simulation results of presented control structures follows experimental ones taken from the electric tricycle.
8
Content available The system of MEMS sensors data streaming and signal quality analysis
Fabiański B., Nowopolski K., Wicher B.
Computer Applications in Electrical Engineering
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2016
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Vol. 14
328--339
EN
In the article, a dedicated testing environment for MEMS sensors is presented. The system serve real–time measurements from several, different interfaced sensors, what gives opportunity to collect the data and – furthermore – its off–line analysis. To complete the main challenge what is MEMS ICs integration in one platform, a special hardware layer is applied together with operational algorithms. Two low–level boards are connected to the embedded server by RS–485 lines. This data server translates RS–485 signals and communicates with dedicated PC program by an Ethernet interface. Such a solution made possible to parallel streaming, archive, and analyze of data in a convenient way. The architecture and operational algorithms of individual components, such as complex synchronization methods in the data streaming process is described. Proper system design is verified by presenting selected signal waveforms grabbed in an experimental tests. In the end introduced two signal quality indicators resulting in comparison of different MEMS ICs. Summary table of computed indicators is shown with its analysis.
9
Content available Burglary detection based on accelometric data using selected signal processing algorithms
Fabiański B., Nowopolski K., Wicher B.
Computer Applications in Electrical Engineering
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2016
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Vol. 14
313--327
EN
The paper presents two approaches to the problem of burglary detection. The first one utilizes direct signal processing, while the other – artificial neural network (ANN). Both algorithms are compared in real operating conditions. The implementation of the algorithms was performed in a portable, battery operating devices that can be easily attached to the door. For direct comparison, two identical devices including several MEMS accelerometers and 32 bit microcontroller have been used – each with one algorithm implemented. The goal of using artificial neural network algorithm was to improve the performance of the burglary detection system in comparison to classical direct signal processing. The structure of ANN and required pre – processing of the input data, is presented and discussed as well. The article also describes the research system required to collecting the data for ANN training and to directly compare both algorithms. Finally, the results of behavior of the classification methods in real actual conditions is discussed.
10
Content available remote Napęd elektryczny i sterowanie trójkołowego roweru bez przekładni mechanicznej
Bielak C., Fabiański B., Janiszewski D., Nowopolski K., Siembab K., Wicher B., Zawirski K.
Przegląd Elektrotechniczny
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2014
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R. 90, nr 6
17--22
PL
W referacie omówiono koncepcję pojazdu napędzanego pedałami (roweru) ze wspomaganiem elektrycznym. Każde z trzech kół pojazdu napędzane jest silnikiem elektrycznym (BLDC) sterowanym przez centralny układ rozdziału mocy. Prędkość ruchu pojazdu oraz moc podawana na silniki są proporcjonalne (z nastawianym przełożeniem) odpowiednio do prędkości i mocy pedałowania. Bateria akumulatorów ładowana jest poprzez napędzaną pedałami prądnicę. Opis i analiza wybranych układów pojazdu udokumentowane są wynikami badań prototypu.
EN
In this paper the idea of an electrically aided pedal-driven vehicle (bicycle) is described. Each of three wheels of the vehicle is driven by electric motor (BLDC) controlled by the central system of power distribution. Velocity of the vehicle and motors power are proportional (with adjustable ratio) to pedaling speed and power respectively. The battery pack is charged by the pedal-driven generator. Description and analysis of the vehicle subsystems are documented with the prototype research results.
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