The Experts below are selected from a list of 2142 Experts worldwide ranked by ideXlab platform
Shinichi Hirai - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Microparts Dynamics Fed Along on an Asymmetric Fabricated Surface with Horizontal and Symmetric Vibrations
2015Co-Authors: Atsushi Mitani, Shinichi HiraiAbstract:Devices to feed along Microparts, such as ceramic chip capacitors and resistors, have become more common, due to their use in sorting, inspecting, and shipping mass produced Microparts. In Microparts feeding, to feed along Microparts in one direction, the driving force applied to each Micropart must vary according to the direction of motion of th
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Feed and align Microparts on symmetrically vibrating saw-tooth surface
Proceeding of the 11th World Congress on Intelligent Control and Automation, 2014Co-Authors: Atsushi Mitani, Thien Xuan, Shinichi HiraiAbstract:This paper proposed a model to simulate Microparts feeding and an alignment method to conduct Microparts following a desired path. On the model aspect, we considered the effect of surrounding fluid the feeding velocity. The attained results show that the model with fluid drag predicted well the behavior and magnitude of the feeding velocity in comparison with experiment data, while the model without fluid drag overestimated the feeding velocity. It implied that fluid plays an important role in the motion of the sub-millimeter Microparts. In addition, a simple method to align Microparts following a desired path on symmetrical vibrating surface was proposed.
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Effect of geometry parameters of saw-tooth surface on the feeding velocity of Microparts
IEEJ Transactions on Electrical and Electronic Engineering, 2013Co-Authors: Thien Xuan Dinh, Atsushi Mitani, Shinichi HiraiAbstract:In this paper, we study experimentally the effect of the geometry parameters of a saw-tooth surface and a Micropart on the motion of the Micropart. The experiments are performed for a range of the saw-tooth pitch p, Micropart length l, and exciting frequency f applied to the surface. By the use of particle tracking velocimetry method, we obtain the time-dependent velocity and then the ensemble-averaged velocity of the Microparts. The results show that the velocity of the Micropart increases up to a certain value of pf and then decreases with increasing pf. The widths of the profiles are similar for the same value of the relative scale l/p but the peaks of the profiles are slightly larger and the profiles are shifted leftward for larger pitches of the saw-tooth surface. It implies that the motion of the Micropart depends more on the characteristic surface velocity pf than on the relative scale l/p and that a larger pitch of the sawtooth creates a larger asymmetric force on the Micropart. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
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AIM - Improvement of sawtooth shape generated by anisotropic etching process of single-crystal silicon for Microparts feeding using horizontal and symmetric vibrations
2013 IEEE ASME International Conference on Advanced Intelligent Mechatronics, 2013Co-Authors: Atsushi Mitani, Yasutaka Matsuo, Shinichi HiraiAbstract:Etching process is a fabrication technology to generate a pattern on a single crystal silicon wafer. The etching process can generate stable and precise periodic pattern on the silicon wafer with a pitch of smaller than 100 μm order according to the etching mask on the surface and characteristics of surface plane orientation. Using a silicon wafer with a plain orientation of [221], an asymmetric periodic structure is generated on its surface because the etching speed is different between forward and backward of the crystal face. We previously showed that Microparts can be fed along an asymmetric microfabricated surface using simple planar symmetric vibrations. Microparts move in one direction because they adhere to the microfabricated surface asymmetrically. We developed sawtoothed surfaces with an elevation angle of 20 deg and various pitches of from 10 to 100 micrometer on the surface of silicon wafer material using a dicing saw with a bevel type blade. Then we found fabrication errors and cracks on the top of teeth, and they caused contact probability among fed Microparts and feeder surfaces, which affected the feeding stability of Microparts. In the present work, we applied the asymmetry etched surface of the [221] oriented single crystal silicon wafer to develop higher accurate and uniform asymmetric fabricated surfaces. The section geometry, the tribology characteristics, and the feeding stability were evaluated among four types of the asymmetry etched silicon wafer pieces we developed in this work. We finally evaluated the stability of Micropart feeding on each surface by the particle tracking velocimetry (PTV) method.
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Evaluation of feeder surface materials for Microparts feeding using an asymmetric fabricated surface with symmetric vibrations
2011 IEEE International Conference on Mechatronics, 2011Co-Authors: Atsushi Mitani, Shinichi HiraiAbstract:We have previously shown that Microparts can be fed along an asymmetric microfabricated surface using simple planar symmetric vibrations. Microparts move forward because they adhere to the microfabricated surface asymmetrically. We have also described the effects of sawtoothed surfaces on the movement of submillimeter Microparts; for example, 0603 (size, 0.6 × 0.6 × 0.3 mm; weight, 0.3 mg) and 0402 (size,0.4 × 0.2 × 0.2 mm; weight, 0.1 mg) capacitors. In the present work, we studied the effects of feeder materials on the feeding of single layer chip capacitors (size, 0.25 × 0.25 × 0.35 mm; weight, 0.06 mg), We found that the motion of submillimeter Microparts was affected not only by inertia but also by adhesion due to electrostatic, van der Waal's, and intermolecular forces, and to surface tension. These effects are dependent on the two materials that are in contact with each other. The four materials selected for feeder surfaces were microfabricated so that periodic sawtooth structures were present on their surfaces. Asymmetry catacteristics of their surfaces were evaluated by the differences in profiles of the two inclined surfaces, and also by the friction angle of Microparts in both the forward and the backward directions. We then assessed Micropart feeding using these surfaces, as well as the relationship between feeding velocity and vibration frequency. By comparing the feeding velocity on each feeder surface, we assessed the effects of feeder surface materials on the feeding of Microparts.
Atsushi Mitani - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Microparts Dynamics Fed Along on an Asymmetric Fabricated Surface with Horizontal and Symmetric Vibrations
2015Co-Authors: Atsushi Mitani, Shinichi HiraiAbstract:Devices to feed along Microparts, such as ceramic chip capacitors and resistors, have become more common, due to their use in sorting, inspecting, and shipping mass produced Microparts. In Microparts feeding, to feed along Microparts in one direction, the driving force applied to each Micropart must vary according to the direction of motion of th
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Feed and align Microparts on symmetrically vibrating saw-tooth surface
Proceeding of the 11th World Congress on Intelligent Control and Automation, 2014Co-Authors: Atsushi Mitani, Thien Xuan, Shinichi HiraiAbstract:This paper proposed a model to simulate Microparts feeding and an alignment method to conduct Microparts following a desired path. On the model aspect, we considered the effect of surrounding fluid the feeding velocity. The attained results show that the model with fluid drag predicted well the behavior and magnitude of the feeding velocity in comparison with experiment data, while the model without fluid drag overestimated the feeding velocity. It implied that fluid plays an important role in the motion of the sub-millimeter Microparts. In addition, a simple method to align Microparts following a desired path on symmetrical vibrating surface was proposed.
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Effect of geometry parameters of saw-tooth surface on the feeding velocity of Microparts
IEEJ Transactions on Electrical and Electronic Engineering, 2013Co-Authors: Thien Xuan Dinh, Atsushi Mitani, Shinichi HiraiAbstract:In this paper, we study experimentally the effect of the geometry parameters of a saw-tooth surface and a Micropart on the motion of the Micropart. The experiments are performed for a range of the saw-tooth pitch p, Micropart length l, and exciting frequency f applied to the surface. By the use of particle tracking velocimetry method, we obtain the time-dependent velocity and then the ensemble-averaged velocity of the Microparts. The results show that the velocity of the Micropart increases up to a certain value of pf and then decreases with increasing pf. The widths of the profiles are similar for the same value of the relative scale l/p but the peaks of the profiles are slightly larger and the profiles are shifted leftward for larger pitches of the saw-tooth surface. It implies that the motion of the Micropart depends more on the characteristic surface velocity pf than on the relative scale l/p and that a larger pitch of the sawtooth creates a larger asymmetric force on the Micropart. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
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AIM - Improvement of sawtooth shape generated by anisotropic etching process of single-crystal silicon for Microparts feeding using horizontal and symmetric vibrations
2013 IEEE ASME International Conference on Advanced Intelligent Mechatronics, 2013Co-Authors: Atsushi Mitani, Yasutaka Matsuo, Shinichi HiraiAbstract:Etching process is a fabrication technology to generate a pattern on a single crystal silicon wafer. The etching process can generate stable and precise periodic pattern on the silicon wafer with a pitch of smaller than 100 μm order according to the etching mask on the surface and characteristics of surface plane orientation. Using a silicon wafer with a plain orientation of [221], an asymmetric periodic structure is generated on its surface because the etching speed is different between forward and backward of the crystal face. We previously showed that Microparts can be fed along an asymmetric microfabricated surface using simple planar symmetric vibrations. Microparts move in one direction because they adhere to the microfabricated surface asymmetrically. We developed sawtoothed surfaces with an elevation angle of 20 deg and various pitches of from 10 to 100 micrometer on the surface of silicon wafer material using a dicing saw with a bevel type blade. Then we found fabrication errors and cracks on the top of teeth, and they caused contact probability among fed Microparts and feeder surfaces, which affected the feeding stability of Microparts. In the present work, we applied the asymmetry etched surface of the [221] oriented single crystal silicon wafer to develop higher accurate and uniform asymmetric fabricated surfaces. The section geometry, the tribology characteristics, and the feeding stability were evaluated among four types of the asymmetry etched silicon wafer pieces we developed in this work. We finally evaluated the stability of Micropart feeding on each surface by the particle tracking velocimetry (PTV) method.
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Evaluation of feeder surface materials for Microparts feeding using an asymmetric fabricated surface with symmetric vibrations
2011 IEEE International Conference on Mechatronics, 2011Co-Authors: Atsushi Mitani, Shinichi HiraiAbstract:We have previously shown that Microparts can be fed along an asymmetric microfabricated surface using simple planar symmetric vibrations. Microparts move forward because they adhere to the microfabricated surface asymmetrically. We have also described the effects of sawtoothed surfaces on the movement of submillimeter Microparts; for example, 0603 (size, 0.6 × 0.6 × 0.3 mm; weight, 0.3 mg) and 0402 (size,0.4 × 0.2 × 0.2 mm; weight, 0.1 mg) capacitors. In the present work, we studied the effects of feeder materials on the feeding of single layer chip capacitors (size, 0.25 × 0.25 × 0.35 mm; weight, 0.06 mg), We found that the motion of submillimeter Microparts was affected not only by inertia but also by adhesion due to electrostatic, van der Waal's, and intermolecular forces, and to surface tension. These effects are dependent on the two materials that are in contact with each other. The four materials selected for feeder surfaces were microfabricated so that periodic sawtooth structures were present on their surfaces. Asymmetry catacteristics of their surfaces were evaluated by the differences in profiles of the two inclined surfaces, and also by the friction angle of Microparts in both the forward and the backward directions. We then assessed Micropart feeding using these surfaces, as well as the relationship between feeding velocity and vibration frequency. By comparing the feeding velocity on each feeder surface, we assessed the effects of feeder surface materials on the feeding of Microparts.
Philippe Lutz - One of the best experts on this subject based on the ideXlab platform.
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Sliding Mode Impedance Controlled Smart Fingered Microgripper for Automated Grasp and Release Tasks at the Microscale
2018Co-Authors: Bilal Komati, Cédric Clévy, Philippe LutzAbstract:The grasp and release of objects have been widely studied in robotics. At the microscale, this problem becomes more difficult due to the microscale specificities which are notably manifested by the high dynamics of microsystems, their small inertia, their fragility, the predominance of surface forces and the high complexity of integrating adapted sensors.In this paper, the problem of the grasp/release task is considered at the microscale. A new nonlinear controller design based on Sliding Mode Impedance Control (SMIC) is proposed to automate the grasp/release of the Micropart. The proposed controller controls dexterously the dynamic interaction between the microgripper and the Micropart and forces the system to follow the desired dynamic relation (impedance). To perform the grasp/release task, a new smart-fingered-microgripper is designed. The microgripper is composed of an active finger with integrated force sensor and a passive finger.The grasp/release of a Micropart of size 50 µm $$ \times $$ 350 µm $$ \times $$ 2 mm is tested in experiments using the control scheme and the developed microgripper. The microgripper design and the control scheme tested show their effectiveness for the grasp/release at the microscale.
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High Bandwidth Microgripper with Integrated Force Sensors and Position Estimation for the Grasp of Multi-stiffness Microcomponents.
IEEE ASME Transactions on Mechatronics, 2016Co-Authors: Bilal Komati, Cédric Clévy, Philippe LutzAbstract:At the microscale, small inertia and high dynamics of Microparts increase the complexity of grasping, releasing and positioning tasks. The difficulty increases especially because the position, the dimensions and the stiffness of the Micropart are unknown. In this paper, the use of a microgripper with integrated sensorized end-effectors with high dynamic capabilities is proposed to perform stable and accurate grasps of multistiffness microcomponents. A dynamic nonlinear force/position model of the complete microgripper while manipulating a microcomponent is developed. The model takes into consideration not only free motion and constrained motion, but also, contact transitions which is a key issue at the microscale due to the predominance of surface forces. It enables to estimate the position of the microgripper’s end-effectors, the contact position of the microcomponent and the force applied on the microcomponent. Using the proposed microgripper and its model, both of the gripping forces are measured and the position of each of the microgripper’s endeffectors is estimated. This enables to perform a stable grasp of the Micropart by providing force and position feedback. Moreover, using the developed microgripper and its model, the characterization of the microcomponent can be performed by estimating its dimensions and its stiffness.
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Automated Micro-assembly tasks based on hybrid Force/position Control.
2010Co-Authors: Kanty Rabenorosoa, Cédric Clévy, Philippe LutzAbstract:Full automated micro-assembly is an ongoing challenge for researchers. The use of force control constitutes a suitable approach to achieve automated micro-assembly. It takes into account microscale specificities like pull off forces, measurement resolution... The integration of force sensors in micro-assembly station is discussed. An experimental setup is proposed to achieve automated guiding tasks of 2mm x 50 μm x 50 μm Microparts. It is based on two-sensing-finger microgripper of 2 mN force range. Interaction forces are modeled and used to establish suitable strategy for guiding according to stability conditions and response time. Control scheme which combines force and position control is proposed and its integration to dSPACE board for real time control is achieved. Automated guiding task is performed with dynamic rejection of perturbation within 35 ms and a ramp tracking with a contact force of 20 μN between the rail side and the Micropart is obtained.
Bilal Komati - One of the best experts on this subject based on the ideXlab platform.
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Sliding Mode Impedance Controlled Smart Fingered Microgripper for Automated Grasp and Release Tasks at the Microscale
2018Co-Authors: Bilal Komati, Cédric Clévy, Philippe LutzAbstract:The grasp and release of objects have been widely studied in robotics. At the microscale, this problem becomes more difficult due to the microscale specificities which are notably manifested by the high dynamics of microsystems, their small inertia, their fragility, the predominance of surface forces and the high complexity of integrating adapted sensors.In this paper, the problem of the grasp/release task is considered at the microscale. A new nonlinear controller design based on Sliding Mode Impedance Control (SMIC) is proposed to automate the grasp/release of the Micropart. The proposed controller controls dexterously the dynamic interaction between the microgripper and the Micropart and forces the system to follow the desired dynamic relation (impedance). To perform the grasp/release task, a new smart-fingered-microgripper is designed. The microgripper is composed of an active finger with integrated force sensor and a passive finger.The grasp/release of a Micropart of size 50 µm $$ \times $$ 350 µm $$ \times $$ 2 mm is tested in experiments using the control scheme and the developed microgripper. The microgripper design and the control scheme tested show their effectiveness for the grasp/release at the microscale.
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High Bandwidth Microgripper with Integrated Force Sensors and Position Estimation for the Grasp of Multi-stiffness Microcomponents.
IEEE ASME Transactions on Mechatronics, 2016Co-Authors: Bilal Komati, Cédric Clévy, Philippe LutzAbstract:At the microscale, small inertia and high dynamics of Microparts increase the complexity of grasping, releasing and positioning tasks. The difficulty increases especially because the position, the dimensions and the stiffness of the Micropart are unknown. In this paper, the use of a microgripper with integrated sensorized end-effectors with high dynamic capabilities is proposed to perform stable and accurate grasps of multistiffness microcomponents. A dynamic nonlinear force/position model of the complete microgripper while manipulating a microcomponent is developed. The model takes into consideration not only free motion and constrained motion, but also, contact transitions which is a key issue at the microscale due to the predominance of surface forces. It enables to estimate the position of the microgripper’s end-effectors, the contact position of the microcomponent and the force applied on the microcomponent. Using the proposed microgripper and its model, both of the gripping forces are measured and the position of each of the microgripper’s endeffectors is estimated. This enables to perform a stable grasp of the Micropart by providing force and position feedback. Moreover, using the developed microgripper and its model, the characterization of the microcomponent can be performed by estimating its dimensions and its stiffness.
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Automated Guiding Task of a Flexible Micropart Using a Two-Sensing-Fingers Microgripper
2013Co-Authors: Bilal Komati, Kanty RabenorosoaAbstract:Abstract—This paper studies automated tasks based on hybrid force/position control of a flexible object at the microscale. A guiding task of a flexible Micropart is the case of the study and is achieved by a two-sensing-finger microgripper. An experimental model of the behavior of the microgripper is given and the interaction forces are studied. Based on grasp stability, a guiding strategy taking into account the pull off forces is proposed. A specific control strategy using an external hybrid force/position control and taking into account microscale specificities is proposed. The experimental results of automated guiding task are presented. Note to Practitioners — This article’s motivation is the need of very precise positioning in micromanipulation and microassembly tasks. The guiding tasks are a part of the microassembly process. Such guiding tasks are rarely automated. This is mainly due to the fact that automation in the microworld is a new issue and the literature only concerns the local control of microactuators and microrobots for the moment. Hybrid force/position control is a promising approach to achieve an automated guiding task of the Micropart. To detect the contact between the Micropart and the rail, a two-sensing-finger microgripper is used. The controller aims to release the contact and to continue going forward within the guiding axis. The proposed controller is very accurate, with high speed (low rejection time) and easy to implement. It is noticed that the proposed control scheme can also be applied to other microassembly tasks (pick-and-place, insertion, etc). Index Terms—Microassembly, hybrid force/position control, automated task, flexible Micropart, compliant Micropart, two-sensing-finger, microgripper, gripping force, lateral contact, mi-crorobot control, microrobotics
Akira Shimokohbe - One of the best experts on this subject based on the ideXlab platform.
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self alignment of Microparts using liquid surface tension behavior of Micropart and alignment characteristics
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2003Co-Authors: Kaiji Sato, Kentaro Ito, Seiichi Hata, Akira ShimokohbeAbstract:Abstract The purpose of this research is to establish a self-alignment technique for Microparts assembly using liquid surface tension. The factors that influence alignment performance are examined and ways of performance improvement are discussed experimentally and theoretically. First, the relationship between the alignment accuracy and the behavior of the Micropart and the water droplet is examined in the alignments with six different water droplet volumes. The experimental results show that the volume influences the alignment accuracy and the behavior. Next, the relationship between restoring force induced theoretically and the experimental alignment accuracy is discussed. Then, the effect of pattern change of the boundary between different wettability areas on the alignment accuracy is examined experimentally. In the experiments, the Micropart with the hexagonal boundary pattern demonstrates smaller alignment error than those with the square, triangular, cross and star patterns.
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Self-alignment of Microparts using liquid surface tension—behavior of Micropart and alignment characteristics
Precision Engineering, 2003Co-Authors: Kaiji Sato, Kentaro Ito, Seiichi Hata, Akira ShimokohbeAbstract:Abstract The purpose of this research is to establish a self-alignment technique for Microparts assembly using liquid surface tension. The factors that influence alignment performance are examined and ways of performance improvement are discussed experimentally and theoretically. First, the relationship between the alignment accuracy and the behavior of the Micropart and the water droplet is examined in the alignments with six different water droplet volumes. The experimental results show that the volume influences the alignment accuracy and the behavior. Next, the relationship between restoring force induced theoretically and the experimental alignment accuracy is discussed. Then, the effect of pattern change of the boundary between different wettability areas on the alignment accuracy is examined experimentally. In the experiments, the Micropart with the hexagonal boundary pattern demonstrates smaller alignment error than those with the square, triangular, cross and star patterns.
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Principle and Characteristics of Microparts Self-alignment using Liquid Surface Tension.
Journal of the Japan Society for Precision Engineering, 2000Co-Authors: Kaiji Sato, Seiichi Hata, Tomonori Seki, Akira ShimokohbeAbstract:This paper describes the self-alignment principle and characteristics using liquid surface tension for the assembly of Microparts. In the principle, the attractive force caused by liquid surface tension is used and servomechnanisms which are too large to align Microparts are not required. The surface of each Micropart is divided into two kinds of areas: the wettability of one area is higher than that of the other. Using the Microparts, the self-alignment is realized as follows: (1) first, a drop of liquid is put on high wettablity surface area of the first part, (2) next, the second part is put on the first one, (3) and then the second part is moved by the surface tension of the liquid so that the wettability area pattern of the first part overlaps with that of the second one, (4) finally, the alignment is accomplished. In this paper, water is used as the liquid. The effects of the water volume change, the position and angle changes of the second part before the alignment on the alignment accuracy are examined experimentally. The experimental results prove that the average of the final alignment errors becomes less than 10μm even if an initial alignment error is 100μm.
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Self-alignment for Microparts assembly using water surface tension
Device and Process Technologies for MEMS and Microelectronics, 1999Co-Authors: Kaiji Sato, Seiichi Hata, Akira ShimokohbeAbstract:Alignment of Microparts is a very important task in the assembly of microsystems. In conventional alignment, servomechanisms are used. However, in general, the servomechanisms are not only too large to align Microparts but also complex and expensive. For overcoming these problems, a self-alignment method using liquid surface tension is proposed in this paper. The surface of the used Microparts is divided into two kinds of areas: the wettability of one area is higher than that of the other. Using the Microparts, the self-alignment is realized as follows: (1) a droplet of liquid is put on high wettability surface area of the first part, (2) the second part is put on the first one, (3) the second part is moved by the surface tension of the liquid so that the wettability area pattern of the first part overlaps with that of the second one and the alignment is accomplished. In this paper, the self-alignment characteristics using water as the liquid is examined experimentally. The experiment results prove the average of the final alignment errors becomes less than 10micrometers even if an initial alignment error is 100micrometers .© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.