Mehatronički pristup pozicioniranju ultravisokih preciznosti i točnosti

Ultra-high precision mechatronics positioning systems are critical devices in current precision engineering and micro- and nano-systems’ technologies, as they allow repeatability and accuracy in the nanometric domain to be achieved. The doctoral thesis deals thoroughly with nonlinear stochastic frictional effects that limit the performances of ultra-high precision devices based on sliding and rolling elements. The state-of-the-art related to the frictional behavior in the pre-sliding and sliding motion regimes is considered and different friction models are validated. Due to its comprehensiveness and simplicity, the generalized Maxwell-slip (GMS) friction model is adopted to characterize frictional disturbances of a translational axis of an actual multi-degrees-of-freedom point-to-point mechatronics positioning system aimed at handling and positioning of microparts. The parameters of the GMS model are identified via innovative experimental set-ups, separately for the actuator-gearhead assembly and for the linear guideways, and included in the overall MATLAB/SIMULINK model of the used device. With the aim of compensating frictional effects, the modeled responses of the system are compared to experimental results when the system is controlled by means of a conventional proportional-integral-derivative (PID) controller, when the PID controller is complemented with an additional feed-forward model-based friction compensator and, finally, when the system is controlled via a self-tuning adaptive regulator. The adaptive regulator, implemented within the real-time field programmable gate array based control system, is proven to be the most efficient and is hence used in the final repetitive point-to-point positioning tests. Nanometric-range precision and accuracy (better than 250 nm), both in the case of short-range (micrometric) and long-range (millimeter) travels, are achieved. Different sensors, actuators and other design components, along with other control typologies, are experimentally validated in ultra-high precision positioning applications as well.Mehatronički sustavi ultra-visokih (nanometarskih) preciznosti i točnosti pozicioniranja su u današnje vrijeme vrlo važni u preciznom inženjerstvu i tehnologiji mikro- i nano-sustava. U disertaciji se temeljito analiziraju nelinearni stohastički učinci trenja koji vrlo često ograničavaju radna svojstva sustava za precizno pozicioniranje temeljenih na kliznim i valjnim elementima. Analizira se stanje tehnike za pomake pri silama manjim od sile statičkog trenja, kao i u režimu klizanja, te se vrednuju postojeći matematički modeli trenja. U razmatranom slučaju mehatroničkog sustava ultra-visokih preciznosti i točnosti pozicioniranja, namijenjenog montaži i manipulaciji mikrostruktura, trenje koje se javlja kod linearnih jednoosnih pomaka se, zbog jednostavnosti i sveobuhvatnosti toga pristupa, modelira generaliziranim Maxwell-slip (GMS) modelom trenja. Parametri GMS modela se identificiraju na inovativnim eksperimentalnim postavima, i to posebno za pokretački dio analiziranog sustava, koji se sastoji od istosmjernog motora s reduktorom, te posebno za linearni translator. Rezultirajući modeli trenja se zatim integriraju u cjeloviti model sustava implementiran u MATLAB/SIMULINK okruženju. S ciljem minimizacije utjecaja trenja, modelirani odziv sustava uspoređuje se potom s eksperimentalnim rezultatima dobivenim na sustavu reguliranom pomoću često korištenog proporcionalno-integralno-diferencijalnog (PID) regulatora, kada se sustav regulira po načelu unaprijedne veze, te kada se regulira prilagodljivim upravljačkim algoritmom. Regulator s prilagodljivim vođenjem, implementiran unutar stvarno-vremenskog sustava temeljenog na programibilnim logičkim vratima, pokazao se kao najbolje rješenje te se stoga koristi u uzastopnim eksperimentima pozicioniranja iz točke u točku, koji predstavljaju željenu funkcionalnost razmatranog sustava. Postignute su tako nanometarska preciznost i točnost (bolje od 250 nm) i to kako kod kraćih (mikrometarskih), tako i duljih (milimetarskih) pomaka. U završnom se dijelu disertacije eksperimentalno analizira i mogućnost korištenja drugih pokretača, osjetnika i strojnih elemenata kao i različitih upravljačkih pristupa pogodnih za ostvarivanje ultra-visokih preciznosti i točnosti pozicioniranja

Mehatronički pristup pozicioniranju ultravisokih preciznosti i točnosti

Ultra-high precision mechatronics positioning systems are critical devices in current precision engineering and micro- and nano-systems’ technologies, as they allow repeatability and accuracy in the nanometric domain to be achieved. The doctoral thesis deals thoroughly with nonlinear stochastic frictional effects that limit the performances of ultra-high precision devices based on sliding and rolling elements. The state-of-the-art related to the frictional behavior in the pre-sliding and sliding motion regimes is considered and different friction models are validated. Due to its comprehensiveness and simplicity, the generalized Maxwell-slip (GMS) friction model is adopted to characterize frictional disturbances of a translational axis of an actual multi-degrees-of-freedom point-to-point mechatronics positioning system aimed at handling and positioning of microparts. The parameters of the GMS model are identified via innovative experimental set-ups, separately for the actuator-gearhead assembly and for the linear guideways, and included in the overall MATLAB/SIMULINK model of the used device. With the aim of compensating frictional effects, the modeled responses of the system are compared to experimental results when the system is controlled by means of a conventional proportional-integral-derivative (PID) controller, when the PID controller is complemented with an additional feed-forward model-based friction compensator and, finally, when the system is controlled via a self-tuning adaptive regulator. The adaptive regulator, implemented within the real-time field programmable gate array based control system, is proven to be the most efficient and is hence used in the final repetitive point-to-point positioning tests. Nanometric-range precision and accuracy (better than 250 nm), both in the case of short-range (micrometric) and long-range (millimeter) travels, are achieved. Different sensors, actuators and other design components, along with other control typologies, are experimentally validated in ultra-high precision positioning applications as well.Mehatronički sustavi ultra-visokih (nanometarskih) preciznosti i točnosti pozicioniranja su u današnje vrijeme vrlo važni u preciznom inženjerstvu i tehnologiji mikro- i nano-sustava. U disertaciji se temeljito analiziraju nelinearni stohastički učinci trenja koji vrlo često ograničavaju radna svojstva sustava za precizno pozicioniranje temeljenih na kliznim i valjnim elementima. Analizira se stanje tehnike za pomake pri silama manjim od sile statičkog trenja, kao i u režimu klizanja, te se vrednuju postojeći matematički modeli trenja. U razmatranom slučaju mehatroničkog sustava ultra-visokih preciznosti i točnosti pozicioniranja, namijenjenog montaži i manipulaciji mikrostruktura, trenje koje se javlja kod linearnih jednoosnih pomaka se, zbog jednostavnosti i sveobuhvatnosti toga pristupa, modelira generaliziranim Maxwell-slip (GMS) modelom trenja. Parametri GMS modela se identificiraju na inovativnim eksperimentalnim postavima, i to posebno za pokretački dio analiziranog sustava, koji se sastoji od istosmjernog motora s reduktorom, te posebno za linearni translator. Rezultirajući modeli trenja se zatim integriraju u cjeloviti model sustava implementiran u MATLAB/SIMULINK okruženju. S ciljem minimizacije utjecaja trenja, modelirani odziv sustava uspoređuje se potom s eksperimentalnim rezultatima dobivenim na sustavu reguliranom pomoću često korištenog proporcionalno-integralno-diferencijalnog (PID) regulatora, kada se sustav regulira po načelu unaprijedne veze, te kada se regulira prilagodljivim upravljačkim algoritmom. Regulator s prilagodljivim vođenjem, implementiran unutar stvarno-vremenskog sustava temeljenog na programibilnim logičkim vratima, pokazao se kao najbolje rješenje te se stoga koristi u uzastopnim eksperimentima pozicioniranja iz točke u točku, koji predstavljaju željenu funkcionalnost razmatranog sustava. Postignute su tako nanometarska preciznost i točnost (bolje od 250 nm) i to kako kod kraćih (mikrometarskih), tako i duljih (milimetarskih) pomaka. U završnom se dijelu disertacije eksperimentalno analizira i mogućnost korištenja drugih pokretača, osjetnika i strojnih elemenata kao i različitih upravljačkih pristupa pogodnih za ostvarivanje ultra-visokih preciznosti i točnosti pozicioniranja

Optimizirani NP i PP filtri drugog i četvrtog reda

In this paper general second-order low-pass and band-pass filter sections are presented. The voltage noise spectral density and Schoeffler sensitivity are calculated for the simple design procedure and for three different types of optimization. The optimization procedure is also done for the forth-order low-pass and band-pass filter. The resulting low noise and sensitivity is investigated using the RMS noise voltage and multi-parameter sensitivity measure. The optimization gives lower noise and lower sensitivity filters. All analyzes are performed using Matlab and Spice programming tools.U radu su prikazane opće filtarske sekcije drugog i četvrtog reda. Izračunati su spektralna gustoća napona šuma i Schoefflerova osjetljivost i to za jednostavan proračun te za tri različita tipa optimizacije. Optimizacija je takođ er provedena za nisko propusni i pojasno propusni filtar četvrtog reda. Dobiveni niski šum kao i osjetljivost ispitani su računanjem efektivne vrijednosti napona šuma i više-parametarske mjere osjetljivosti. Rezultati optimizacije daju filtre koji imaju manji šum k ao i osjetljivost. Svi su proračuni izvedeni korištenjem programskih alata Matlab i Spice

Friction compensation in ultrahigh-precision positioning

Ultrahigh -precision positioning devices are essential in precision engineering and microsystems’ technologies. As they need to allow sub- micrometric or even nanometric displacements, their nonlinear frictional behaviour, induced by a number of sliding and rolling components, has to be efficiently compensated for. If a model-based approach is followed, suitable modelling of such disturbances, which is generally performed using state-of the art friction models, has to be performed. An overview of different compensation and control algorithms applied to ultrahigh-precision positioning systems is hence given in this work

Model šake s međuovisnim zglobovima za primjenu u rehabilitacijskoj robotici

Aim: This work presents a method for developing a simplified but efficient model of the complex human hand kinematics with the aim of its implementation in rehabilitation robotics. Material and methods: The approach incorporates modularity by simplifying the available model comprising 24 degrees of freedom (DOFs) to 9 DOFs, with the introduction of additional joint coupling parameters specific to different grasp types. The effect of dependent joints to the ranges-of-motion (ROMs) of the model is investigated and compared to the anatomical one. The index, middle, ring and little finger solutions to forward and inverse kinematics problems are then acquired. The implementation of the model, based on the median male bones dimensions, is made available in the open-source Robot Operating System (ROS) framework. Results: By including additional four inclination angles per finger, the devised kinematic hand model encompasses also finger curvatures, resulting in significant positioning accuracy improvements compared to the conventional model. The used 3D spatial position improvement metrics are the mean absolute (MAE) and mean relative errors (MRE). The dependent joint position MAEs range from 0.22 to 0.34 cm, while MREs range from 2.8 and 3.5 %, whereas the highest absolute and relative errors during fingertip positioning can reach 0.5 cm and 10.5 %, respectively. Conclusion: The performed investigation allowed establishing that by modelling finger curvature and assuring the adaptability of the model to a variety of human hands and rehabilitation modalities through joint dependency, represents the best approach towards a relatively simple and applicable rehabilitation model with functional human-like hand movements.Cilj: U radu se prezentira metoda za razvoj pojednostavljenog ali učinkovitog kinematičkog modela ljudske ruke koji će se implementirati u rehabilitacijskoj robotici. Materijali i metode: Pristup se temelji na pojednostavljenju postojećeg modela koji ima 24 stupnja slobode gibanja (DOF) na 9 DOF-a, uz uvođenje dodatnih konstrukcijskih parametara, specifičnih za različite vrste hvata. Nakon što je istražen utjecaj ovisnih zglobova na raspon pokreta (ROM) modela, te je isti uspoređen s anatomskim modelom, dobivena su rješenja problema inverzne i direktne kinematike kažiprsta, srednjeg prsta, prstenjaka i malog prsta. Implementacija modela, temeljena na dimenzijama muških kostiju koje odgovaraju medijanu muške populacije, ostvarena je pomoću programskog okruženja otvorenog koda Robot Operating System (ROS). Rezultati: Uzimanjem u obzir četiriju dodatnih kutova nagiba po prstu, razvijeni model ruke obuhvaća i zakrivljenost prstiju, što omogućuje povećanje točnosti pozicioniranja u usporedbi s konvencionalnim modelom. Kao mjerila za utvrđivanje povećanja točnosti prostornog pozicioniranja, korištene su srednja apsolutna greška (MAE) i srednja relativna greška (MRE). MAE se, ovisno o položaju zgloba, kreće od 0,22 do 0,34 cm, dok se MRE kreće od 2,8 do 3,5 %. Najveće apsolutne i relativne greške tijekom pozicioniranja vrha prsta mogu, pak, doseći 0,5 cm, odnosno 10,5 %. Zaključak: Zaključuje se da modeliranje zakrivljenosti prsta i osiguranje prilagodljivosti modela različitim pacijentima i rehabilitacijskim modalitetima kroz međuovisnost zglobova, predstavlja najbolji pristup dobivanju relativno jednostavnog, primjenjivog i funkcionalnog modela šake

Kinetic Energy Harvesting for Wearable Medical Sensors

The process of collecting low-level kinetic energy, which is present in all moving systems, by using energy harvesting principles, is of particular interest in wearable technology, especially in ultra-low power devices for medical applications. In fact, the replacement of batteries with innovative piezoelectric energy harvesting devices can result in mass and size reduction, favoring the miniaturization of wearable devices, as well as drastically increasing their autonomy. The aim of this work is to assess the power requirements of wearable sensors for medical applications, and address the intrinsic problem of piezoelectric kinetic energy harvesting devices that can be used to power them; namely, the narrow area of optimal operation around the eigenfrequencies of a specific device. This is achieved by using complex numerical models comprising modal, harmonic and transient analyses. In order to overcome the random nature of excitations generated by human motion, novel excitation modalities are investigated with the goal of increasing the specific power outputs. A solution embracing an optimized harvester geometry and relying on an excitation mechanism suitable for wearable medical sensors is hence proposed. The electrical circuitry required for efficient energy management is considered as well.publishedVersionPeer reviewe

Mjerenje i analiza vibracija energetskih transformatora s ciljem smanjenja buke

Karakterizacija dinamičkog odziva je ključna pri analizi buke energetskih transformatora te određivanju mjera za minimizaciju buke. Nastajanje buke je uvjetovano međudjelovanjem uzbude jezgre i namotaja te prijenosom uzbude fluidom za hlađenje do oplate. Taj kompleksni mehanizam može se analizirati jedino naprednim numeričkim modelima temeljenim na mjerenjima. U ovom se radu, kao izvanredan primjer prijenosa znanja, opisuje napredna vremenska i frekvencijska analiza vibracijskih učinaka temeljena na pažljivom planiranju eksperimenata DoE metodama te opsežnim eksperimentalnim mjerenjima dinamičkog odziva oplate energetskog transformatora tvrtke Končar D&ST d.d. provedenima koristeći beskontaktnu lasersku Doppler interferometrijsku metodu. Provedena analiza stvara preduvjete za razvoj modela koji će omogućiti unapređenje konstrukcije analiziranih kompleksnih sustava s ciljem smanjenja buke te daljnjeg zadovoljavanja sve strožih međunarodnih normi za energetske transformatore

Mjerenje i analiza vibracija energetskih transformatora s ciljem smanjenja buke

Karakterizacija dinamičkog odziva je ključna pri analizi buke energetskih transformatora te određivanju mjera za minimizaciju buke. Nastajanje buke je uvjetovano međudjelovanjem uzbude jezgre i namotaja te prijenosom uzbude fluidom za hlađenje do oplate. Taj kompleksni mehanizam može se analizirati jedino naprednim numeričkim modelima temeljenim na mjerenjima. U ovom se radu, kao izvanredan primjer prijenosa znanja, opisuje napredna vremenska i frekvencijska analiza vibracijskih učinaka temeljena na pažljivom planiranju eksperimenata DoE metodama te opsežnim eksperimentalnim mjerenjima dinamičkog odziva oplate energetskog transformatora tvrtke Končar D&ST d.d. provedenima koristeći beskontaktnu lasersku Doppler interferometrijsku metodu. Provedena analiza stvara preduvjete za razvoj modela koji će omogućiti unapređenje konstrukcije analiziranih kompleksnih sustava s ciljem smanjenja buke te daljnjeg zadovoljavanja sve strožih međunarodnih normi za energetske transformatore

Energy harvesting technologies for structural health monitoring of airplane components - a review

With the aim of increasing the efficiency of maintenance and fuel usage in airplanes, structural health monitoring (SHM) of critical composite structures is increasingly expected and required. The optimized usage of this concept is subject of intensive work in the framework of the EU COST Action CA18203 "Optimising Design for Inspection" (ODIN). In this context, a thorough review of a broad range of energy harvesting (EH) technologies to be potentially used as power sources for the acoustic emission and guided wave propagation sensors of the considered SHM systems, as well as for the respective data elaboration and wireless communication modules, is provided in this work. EH devices based on the usage of kinetic energy, thermal gradients, solar radiation, airflow, and other viable energy sources, proposed so far in the literature, are thus described with a critical review of the respective specific power levels, of their potential placement on airplanes, as well as the consequently necessary power management architectures. The guidelines provided for the selection of the most appropriate EH and power management technologies create the preconditions to develop a new class of autonomous sensor nodes for the in-process, non-destructive SHM of airplane components.The work of S. Zelenika, P. Gljušcic, E. Kamenar and Ž. Vrcan is partly enabled by using the equipment funded via the EU European Regional Development Fund (ERDF) project no. RC.2.2.06-0001: “Research Infrastructure for Campus-based Laboratories at the University of Rijeka (RISK)” and partly supported by the University of Rijeka, Croatia, project uniri-tehnic-18-32 „Advanced mechatronics devices for smart technological solutions“. Z. Hadas, P. Tofel and O. Ševecek acknowledge the support provided via the Czech Science Foundation project GA19-17457S „Manufacturing and analysis of flexible piezoelectric layers for smart engineering”. J. Hlinka, F. Ksica and O. Rubes gratefully acknowledge the financial support provided by the ESIF, EU Operational Programme Research, Development and Education within the research project Center of Advanced Aerospace Technology (Reg. No.: CZ.02.1.01/0.0/0.0/16_019/0000826) at the Faculty of Mechanical Engineering, Brno University of Technology. V. Pakrashi would like to acknowledge UCD Energy Institute, Marine and Renewable Energy Ireland (MaREI) centre Ireland, Strengthening Infrastructure Risk Assessment in the Atlantic Area (SIRMA) Grant No. EAPA\826/2018, EU INTERREG Atlantic Area and Aquaculture Operations with Reliable Flexible Shielding Technologies for Prevention of Infestation in Offshore and Coastal Areas (FLEXAQUA), MarTera Era-Net cofund PBA/BIO/18/02 projects. The work of J.P.B. Silva is partially supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/FIS/04650/2020. M. Mrlik gratefully acknowledges the support of the Ministry of Education, Youth and Sports of the Czech Republic-DKRVO (RP/CPS/2020/003

Mehatronički pristup pozicioniranju ultravisokih preciznosti i točnosti

Ultra-high precision mechatronics positioning systems are critical devices in current precision engineering and micro- and nano-systems’ technologies, as they allow repeatability and accuracy in the nanometric domain to be achieved. The doctoral thesis deals thoroughly with nonlinear stochastic frictional effects that limit the performances of ultra-high precision devices based on sliding and rolling elements. The state-of-the-art related to the frictional behavior in the pre-sliding and sliding motion regimes is considered and different friction models are validated. Due to its comprehensiveness and simplicity, the generalized Maxwell-slip (GMS) friction model is adopted to characterize frictional disturbances of a translational axis of an actual multi-degrees-of-freedom point-to-point mechatronics positioning system aimed at handling and positioning of microparts. The parameters of the GMS model are identified via innovative experimental set-ups, separately for the actuator-gearhead assembly and for the linear guideways, and included in the overall MATLAB/SIMULINK model of the used device. With the aim of compensating frictional effects, the modeled responses of the system are compared to experimental results when the system is controlled by means of a conventional proportional-integral-derivative (PID) controller, when the PID controller is complemented with an additional feed-forward model-based friction compensator and, finally, when the system is controlled via a self-tuning adaptive regulator. The adaptive regulator, implemented within the real-time field programmable gate array based control system, is proven to be the most efficient and is hence used in the final repetitive point-to-point positioning tests. Nanometric-range precision and accuracy (better than 250 nm), both in the case of short-range (micrometric) and long-range (millimeter) travels, are achieved. Different sensors, actuators and other design components, along with other control typologies, are experimentally validated in ultra-high precision positioning applications as well.Mehatronički sustavi ultra-visokih (nanometarskih) preciznosti i točnosti pozicioniranja su u današnje vrijeme vrlo važni u preciznom inženjerstvu i tehnologiji mikro- i nano-sustava. U disertaciji se temeljito analiziraju nelinearni stohastički učinci trenja koji vrlo često ograničavaju radna svojstva sustava za precizno pozicioniranje temeljenih na kliznim i valjnim elementima. Analizira se stanje tehnike za pomake pri silama manjim od sile statičkog trenja, kao i u režimu klizanja, te se vrednuju postojeći matematički modeli trenja. U razmatranom slučaju mehatroničkog sustava ultra-visokih preciznosti i točnosti pozicioniranja, namijenjenog montaži i manipulaciji mikrostruktura, trenje koje se javlja kod linearnih jednoosnih pomaka se, zbog jednostavnosti i sveobuhvatnosti toga pristupa, modelira generaliziranim Maxwell-slip (GMS) modelom trenja. Parametri GMS modela se identificiraju na inovativnim eksperimentalnim postavima, i to posebno za pokretački dio analiziranog sustava, koji se sastoji od istosmjernog motora s reduktorom, te posebno za linearni translator. Rezultirajući modeli trenja se zatim integriraju u cjeloviti model sustava implementiran u MATLAB/SIMULINK okruženju. S ciljem minimizacije utjecaja trenja, modelirani odziv sustava uspoređuje se potom s eksperimentalnim rezultatima dobivenim na sustavu reguliranom pomoću često korištenog proporcionalno-integralno-diferencijalnog (PID) regulatora, kada se sustav regulira po načelu unaprijedne veze, te kada se regulira prilagodljivim upravljačkim algoritmom. Regulator s prilagodljivim vođenjem, implementiran unutar stvarno-vremenskog sustava temeljenog na programibilnim logičkim vratima, pokazao se kao najbolje rješenje te se stoga koristi u uzastopnim eksperimentima pozicioniranja iz točke u točku, koji predstavljaju željenu funkcionalnost razmatranog sustava. Postignute su tako nanometarska preciznost i točnost (bolje od 250 nm) i to kako kod kraćih (mikrometarskih), tako i duljih (milimetarskih) pomaka. U završnom se dijelu disertacije eksperimentalno analizira i mogućnost korištenja drugih pokretača, osjetnika i strojnih elemenata kao i različitih upravljačkih pristupa pogodnih za ostvarivanje ultra-visokih preciznosti i točnosti pozicioniranja