Georg Schitter | Tu Wien (original) (raw)
Papers by Georg Schitter
Bitumen is the binder in the composite material named asphalt concrete. Under cyclic mechanical l... more Bitumen is the binder in the composite material named asphalt concrete. Under cyclic mechanical loading of traffic passing over the pavement, eventually damage will initiate in the pavement, leading to eventual structural failure. This damaging process is accelerated by time dependent change of the mechanical properties of asphalt concrete due to ageing mechanisms like oxidation. Bitumen displays spatial heterogeneity at the micrometer scale, which has been observed by atomic force microscopy (AFM). The mechanical properties of the elliptical, microstructural domains of bitumen are distinct from those of the continuous phase. This introduces stiffness discontinuities in the material, which under mechanical loading will concentrate stresses at the interfaces, and thus the locations where early stages of damage will develop. This work aims at in situ probing of the crack healing of bituminous materials as a function of moderate temperature changes. The bitumen was prepared on a flexib...
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Mechatronics, 2021
This paper proposes a novel self-sensing control concept for resonant MEMS mirrors solely based o... more This paper proposes a novel self-sensing control concept for resonant MEMS mirrors solely based on the comb-drive current generated by the mirror movement and simple circuitry. Phase errors are immediately compensated by asynchronous switching of the driving voltage using the precise zero crossing detection by the steep current gradient. The mirror amplitude is detected based on the time difference between a comparator threshold crossing of the current signal and the zero crossing of the mirror, while it is controlled by the duty cycle of the driving voltage signal. The proper threshold setting is analyzed regarding the obtained sensitivity and uncertainty of the amplitude detection and is verified by measurements. It is found that even for symmetric out-of-plane comb-drives the scanning direction can be determined utilizing the mode coupling phenomenon of a lightweight MEMS mirror design with reinforcement structure. Experiments show that the proposed control concept results in a l...
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2018 IEEE Conference on Control Technology and Applications (CCTA), 2018
This paper presents the utilization of a disturbance observer (DOB) with robust loop shaping filt... more This paper presents the utilization of a disturbance observer (DOB) with robust loop shaping filter to achieve robust stability in presence of significant plant uncertainty. Finite element analysis together with frequency response measurements are used to analyze position dependent plant uncertainty. Three different shaping filter are proposed including elliptic filter and an adaptive notch filter. The different concepts are implemented on a dual axis precision motion platform, which is actuated by direct-drive permanent magnet synchronous motors (PMSMs). Experimental validation is carried out to investigate the performance of the system. Using the proposed robust control, the angular precision is improved by a factor of 2.2 from pmb1.03mumathbfrad\pmb{1.03\ \mu} \mathbf{rad}pmb1.03mumathbfrad to pmb0.46mumathbfrad\pmb{0.46\ \mu}\mathbf{rad}pmb0.46mumathbfrad, and this level of precision is maintained over the entire positioning and velocity range.
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2018 IEEE 23rd International Conference on Emerging Technologies and Factory Automation (ETFA)
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IEEE Transactions on Instrumentation and Measurement
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Optics Express
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IEEE Transactions on Industrial Informatics
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IEEE/ASME Transactions on Mechatronics
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Applied Optics
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Journal of the Optical Society of America A
Confocal chromatic displacement sensors are versatile and precise sensors for measuring the dista... more Confocal chromatic displacement sensors are versatile and precise sensors for measuring the distance to a single point. In order to obtain a 3D measurement device, this paper presents an integrated scanning sensor design that employs a tilting lens mechanism for manipulating the light path of the sensor. The optical implications of the design are analytically modeled and simulated. An experimental setup is constructed to evaluate the system design and to test its performance on a variety of samples. Results show good agreement with the simulations and modeling; with maximal tip/tilt angles of ±2.5∘, the setup is capable of measuring a volume of 1.7×1.7×1mm3 with a lateral resolution of 24.8 µm and an axial resolution of 3 µm.
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IFAC-PapersOnLine
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Abstract This paper proposes a sample-tracking vibration isolator based on hybrid reluctance actu... more Abstract This paper proposes a sample-tracking vibration isolator based on hybrid reluctance actuators to bring a vibration sensitive instrument toward inline metrology. The hybrid reluctance actuators vertically move the platform to mount the instrument and maintain its position with respect to the target sample, rejecting floor vibrations. For compensating crosstalk motions due to manufacturing and assembly tolerances, the actuator forces are balanced, demonstrating a reduction by a factor of about 10 for frequencies below 70 Hz. In order to regulate the moving platform motion, a feedback controller is designed achieving a closed-loop bandwidth of 260 Hz. Experiments reveal that the proposed vibration isolator reduces the vibrations (RMS value) from 37.5nm to 1.6 nm and consequently realizes nanometer positioning resolution in a vibrational environment. These experiments successfully demonstrate the effectiveness of the proposed vibration isolator and the capability of the hybrid reluctance actuators to handle floor vibrations.
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IFAC-PapersOnLine
Abstract In hybrid reluctance actuators for high precision motion control, the magnetic hysteresi... more Abstract In hybrid reluctance actuators for high precision motion control, the magnetic hysteresis in the ferromagnetic stator and mover usually affects the precision. Therefore, this paper proposes magnetic flux estimation and control to compensate for the hysteresis. To measure the magnetic flux at various frequencies, the output signal of a search coil is combined with that of the current monitor of the employed current amplifier in a magnetic flux estimator. Finally, a magnetic flux controller is designed and implemented. For evaluation of the hysteresis compensation, the performance of the hybrid reluctance actuator is compared with both flux and current control. Experimental results show that flux control successfully compensates for some of the nonlinearities of the hybrid reluctance actuator, as the hysteresis is reduced by up to a factor 8.2 and the phase lag of the mover position is reduced by up to 6 deg in comparison with the case of current control.
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e & i Elektrotechnik und Informationstechnik
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IEEJ Journal of Industry Applications
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IEEE/ASME Transactions on Mechatronics
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IEEJ Journal of Industry Applications
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IEEJ Journal of Industry Applications
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Bitumen is the binder in the composite material named asphalt concrete. Under cyclic mechanical l... more Bitumen is the binder in the composite material named asphalt concrete. Under cyclic mechanical loading of traffic passing over the pavement, eventually damage will initiate in the pavement, leading to eventual structural failure. This damaging process is accelerated by time dependent change of the mechanical properties of asphalt concrete due to ageing mechanisms like oxidation. Bitumen displays spatial heterogeneity at the micrometer scale, which has been observed by atomic force microscopy (AFM). The mechanical properties of the elliptical, microstructural domains of bitumen are distinct from those of the continuous phase. This introduces stiffness discontinuities in the material, which under mechanical loading will concentrate stresses at the interfaces, and thus the locations where early stages of damage will develop. This work aims at in situ probing of the crack healing of bituminous materials as a function of moderate temperature changes. The bitumen was prepared on a flexib...
Bookmarks Related papers MentionsView impact
Mechatronics, 2021
This paper proposes a novel self-sensing control concept for resonant MEMS mirrors solely based o... more This paper proposes a novel self-sensing control concept for resonant MEMS mirrors solely based on the comb-drive current generated by the mirror movement and simple circuitry. Phase errors are immediately compensated by asynchronous switching of the driving voltage using the precise zero crossing detection by the steep current gradient. The mirror amplitude is detected based on the time difference between a comparator threshold crossing of the current signal and the zero crossing of the mirror, while it is controlled by the duty cycle of the driving voltage signal. The proper threshold setting is analyzed regarding the obtained sensitivity and uncertainty of the amplitude detection and is verified by measurements. It is found that even for symmetric out-of-plane comb-drives the scanning direction can be determined utilizing the mode coupling phenomenon of a lightweight MEMS mirror design with reinforcement structure. Experiments show that the proposed control concept results in a l...
Bookmarks Related papers MentionsView impact
2018 IEEE Conference on Control Technology and Applications (CCTA), 2018
This paper presents the utilization of a disturbance observer (DOB) with robust loop shaping filt... more This paper presents the utilization of a disturbance observer (DOB) with robust loop shaping filter to achieve robust stability in presence of significant plant uncertainty. Finite element analysis together with frequency response measurements are used to analyze position dependent plant uncertainty. Three different shaping filter are proposed including elliptic filter and an adaptive notch filter. The different concepts are implemented on a dual axis precision motion platform, which is actuated by direct-drive permanent magnet synchronous motors (PMSMs). Experimental validation is carried out to investigate the performance of the system. Using the proposed robust control, the angular precision is improved by a factor of 2.2 from pmb1.03mumathbfrad\pmb{1.03\ \mu} \mathbf{rad}pmb1.03mumathbfrad to pmb0.46mumathbfrad\pmb{0.46\ \mu}\mathbf{rad}pmb0.46mumathbfrad, and this level of precision is maintained over the entire positioning and velocity range.
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2018 IEEE 23rd International Conference on Emerging Technologies and Factory Automation (ETFA)
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IEEE Transactions on Instrumentation and Measurement
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Optics Express
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IEEE Transactions on Industrial Informatics
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IEEE/ASME Transactions on Mechatronics
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Applied Optics
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Journal of the Optical Society of America A
Confocal chromatic displacement sensors are versatile and precise sensors for measuring the dista... more Confocal chromatic displacement sensors are versatile and precise sensors for measuring the distance to a single point. In order to obtain a 3D measurement device, this paper presents an integrated scanning sensor design that employs a tilting lens mechanism for manipulating the light path of the sensor. The optical implications of the design are analytically modeled and simulated. An experimental setup is constructed to evaluate the system design and to test its performance on a variety of samples. Results show good agreement with the simulations and modeling; with maximal tip/tilt angles of ±2.5∘, the setup is capable of measuring a volume of 1.7×1.7×1mm3 with a lateral resolution of 24.8 µm and an axial resolution of 3 µm.
Bookmarks Related papers MentionsView impact
IFAC-PapersOnLine
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IFAC-PapersOnLine
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IFAC-PapersOnLine
Abstract This paper proposes a sample-tracking vibration isolator based on hybrid reluctance actu... more Abstract This paper proposes a sample-tracking vibration isolator based on hybrid reluctance actuators to bring a vibration sensitive instrument toward inline metrology. The hybrid reluctance actuators vertically move the platform to mount the instrument and maintain its position with respect to the target sample, rejecting floor vibrations. For compensating crosstalk motions due to manufacturing and assembly tolerances, the actuator forces are balanced, demonstrating a reduction by a factor of about 10 for frequencies below 70 Hz. In order to regulate the moving platform motion, a feedback controller is designed achieving a closed-loop bandwidth of 260 Hz. Experiments reveal that the proposed vibration isolator reduces the vibrations (RMS value) from 37.5nm to 1.6 nm and consequently realizes nanometer positioning resolution in a vibrational environment. These experiments successfully demonstrate the effectiveness of the proposed vibration isolator and the capability of the hybrid reluctance actuators to handle floor vibrations.
Bookmarks Related papers MentionsView impact
IFAC-PapersOnLine
Abstract In hybrid reluctance actuators for high precision motion control, the magnetic hysteresi... more Abstract In hybrid reluctance actuators for high precision motion control, the magnetic hysteresis in the ferromagnetic stator and mover usually affects the precision. Therefore, this paper proposes magnetic flux estimation and control to compensate for the hysteresis. To measure the magnetic flux at various frequencies, the output signal of a search coil is combined with that of the current monitor of the employed current amplifier in a magnetic flux estimator. Finally, a magnetic flux controller is designed and implemented. For evaluation of the hysteresis compensation, the performance of the hybrid reluctance actuator is compared with both flux and current control. Experimental results show that flux control successfully compensates for some of the nonlinearities of the hybrid reluctance actuator, as the hysteresis is reduced by up to a factor 8.2 and the phase lag of the mover position is reduced by up to 6 deg in comparison with the case of current control.
Bookmarks Related papers MentionsView impact
e & i Elektrotechnik und Informationstechnik
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IEEJ Journal of Industry Applications
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IEEE/ASME Transactions on Mechatronics
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IEEJ Journal of Industry Applications
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IEEJ Journal of Industry Applications
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IEEJ Journal of Industry Applications
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