Pub Date : 2022-07-05DOI: 10.20965/ijat.2022.p0386
Lei Zhou, Jingjie Wu
Precision motion systems are the core of a wide range of manufacturing equipment and scientific instruments, and their motion performance directly determines the quality and speed of the associated manufacturing or metrology processes. Magnetically levitated precision motion systems, where the moving target is supported by magnetic forces and without any mechanical contact, provide advantages of frictionless motion, vacuum compatibility, and contamination-free operation. These features endow the magnetic levitation technology with the capability to deliver excellent overall performance for precision positioning systems. Through decades of research and engineering efforts, significant advances have been made in the actuation, sensing, design, and control of magnetically levitated precision motion systems. This paper provides an introduction to the fundamentals of the feedback control, actuation, and sensing for the magnetic levitation technology, and provides a comprehensive literature review of various magnetically levitated precision positioning systems developed over the past three decades. The final part of this paper identifies several challenges in the design and control of today’s precision motion systems using magnetic levitation and provides an outlook on the possible directions for future research and development.
{"title":"Magnetic Levitation Technology for Precision Motion Systems: A Review and Future Perspectives","authors":"Lei Zhou, Jingjie Wu","doi":"10.20965/ijat.2022.p0386","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0386","url":null,"abstract":"Precision motion systems are the core of a wide range of manufacturing equipment and scientific instruments, and their motion performance directly determines the quality and speed of the associated manufacturing or metrology processes. Magnetically levitated precision motion systems, where the moving target is supported by magnetic forces and without any mechanical contact, provide advantages of frictionless motion, vacuum compatibility, and contamination-free operation. These features endow the magnetic levitation technology with the capability to deliver excellent overall performance for precision positioning systems. Through decades of research and engineering efforts, significant advances have been made in the actuation, sensing, design, and control of magnetically levitated precision motion systems. This paper provides an introduction to the fundamentals of the feedback control, actuation, and sensing for the magnetic levitation technology, and provides a comprehensive literature review of various magnetically levitated precision positioning systems developed over the past three decades. The final part of this paper identifies several challenges in the design and control of today’s precision motion systems using magnetic levitation and provides an outlook on the possible directions for future research and development.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"18 1","pages":"386-402"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74949750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.20965/ijat.2022.p0403
Natanael Lanz, S. Weikert, K. Wegener
This paper presents a novel parametrization strategy for optimal contouring control of flexible feed drives. The aim of the new strategy is to maximize the structural damping of the drive and counteract the deformations of the structure. Using a simplified flexible multibody model, the analytical relationships for the design of velocity and position control gains were derived. This results in a controller bandwidth increase of up to 20% compared to the previous state-of-the-art in parametrization of standard cascaded controllers. Through analytical and numerical calculations, it was demonstrated that such an increase is feasible without a decrease in structural damping if the position and velocity controller gains are both considered. Furthermore, it is shown that the ratio between the position and velocity loop gains influences the quasistatic deformation between the encoder and tool center point (TCP). A formula for the optimal choice of the ratio was derived to compensate for the error. This leads to a new straightforward step-by-step approach for axis controller setting, which is then applied to a test bench and its simulation model. It can be shown that the new parametrization strategy leads to a significant reduction in path error at the TCP. Importantly, the analytical approach should simplify the task of setting up a standard cascaded controller significantly by avoiding time-consuming iterations.
{"title":"New Control Parametrization Strategy for Flexible Feed Drives","authors":"Natanael Lanz, S. Weikert, K. Wegener","doi":"10.20965/ijat.2022.p0403","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0403","url":null,"abstract":"This paper presents a novel parametrization strategy for optimal contouring control of flexible feed drives. The aim of the new strategy is to maximize the structural damping of the drive and counteract the deformations of the structure. Using a simplified flexible multibody model, the analytical relationships for the design of velocity and position control gains were derived. This results in a controller bandwidth increase of up to 20% compared to the previous state-of-the-art in parametrization of standard cascaded controllers. Through analytical and numerical calculations, it was demonstrated that such an increase is feasible without a decrease in structural damping if the position and velocity controller gains are both considered. Furthermore, it is shown that the ratio between the position and velocity loop gains influences the quasistatic deformation between the encoder and tool center point (TCP). A formula for the optimal choice of the ratio was derived to compensate for the error. This leads to a new straightforward step-by-step approach for axis controller setting, which is then applied to a test bench and its simulation model. It can be shown that the new parametrization strategy leads to a significant reduction in path error at the TCP. Importantly, the analytical approach should simplify the task of setting up a standard cascaded controller significantly by avoiding time-consuming iterations.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"27 1","pages":"403-420"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76598566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.20965/ijat.2022.p0456
Tomohiro Tanaka, Tomonori Kato, T. Otsubo, Atsuhiro Koyama, T. Yazawa
Air turbine spindles with aerostatic bearings are widely used in ultraprecision machining equipment. Ultraprecision grinding processes using air turbine spindles with aerostatic bearings include constant-pressure dry lapping of nano-polycrystalline diamond (NPD) tools and ultraviolet irradiation polishing of chemical vapor deposition diamond films. In the dry lapping of NPD tools, it is necessary to achieve constant-pressure grinding while flexibly adjusting the contact force between the NPD tool and the truer fixed on the end face of the aerostatic spindle to form a nose bite with a cutting-edge rounding radius, R, of 0.1 nm. However, it is common for operators to manually adjust the cut depth and the air pressure supplied to the aerostatic bearing by relying on the noise and rotation speed during machining. Moreover, aerostatic spindles without a control mechanism, such as active bearings, are widely used because of their low costs and versatility. For several years, the authors have been developing a method to control air bearing stiffness by controlling the bearing supply pressure with high speeds and precision using a high-precision quick response regulator for aerostatic spindles without a control mechanism, such as active bearings. In this study, the compliance control (control of spindle position and stiffness) of aerostatic bearings was investigated using the proposed method, and the effectiveness of the method to ultraprecision grinding applications was demonstrated.
{"title":"Control of Spindle Position and Stiffness of Aerostatic-Bearing-Type Air Turbine Spindle","authors":"Tomohiro Tanaka, Tomonori Kato, T. Otsubo, Atsuhiro Koyama, T. Yazawa","doi":"10.20965/ijat.2022.p0456","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0456","url":null,"abstract":"Air turbine spindles with aerostatic bearings are widely used in ultraprecision machining equipment. Ultraprecision grinding processes using air turbine spindles with aerostatic bearings include constant-pressure dry lapping of nano-polycrystalline diamond (NPD) tools and ultraviolet irradiation polishing of chemical vapor deposition diamond films. In the dry lapping of NPD tools, it is necessary to achieve constant-pressure grinding while flexibly adjusting the contact force between the NPD tool and the truer fixed on the end face of the aerostatic spindle to form a nose bite with a cutting-edge rounding radius, R, of 0.1 nm. However, it is common for operators to manually adjust the cut depth and the air pressure supplied to the aerostatic bearing by relying on the noise and rotation speed during machining. Moreover, aerostatic spindles without a control mechanism, such as active bearings, are widely used because of their low costs and versatility. For several years, the authors have been developing a method to control air bearing stiffness by controlling the bearing supply pressure with high speeds and precision using a high-precision quick response regulator for aerostatic spindles without a control mechanism, such as active bearings. In this study, the compliance control (control of spindle position and stiffness) of aerostatic bearings was investigated using the proposed method, and the effectiveness of the method to ultraprecision grinding applications was demonstrated.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"9 1","pages":"456-463"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73881910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.20965/ijat.2022.p0471
Y. Taoka, Kohei Kawabata, P. Hemthavy, Seungman Choi, Kunio Takahashi, S. Saito
This technical paper demonstrates the influence of the probe-tip surface smoothness of a bipolar electrostatic chuck (ESC) on electrostatic force. ESC, which has a silicon-based beam-array microstructure, aims to pick and place a dielectric object with a curved surface owing to the compliance of its elastically deformable beams. The ESC was fabricated using a lithography technique, specifically deep reactive ion etching (DRIE), to smooth the surface of the beam tip. The surface roughness of the beam tips was observed using a field-emission scanning electron microscope (FE-SEM), and the adhesional force was experimentally evaluated. The results show that by the smoothing process, the adhesional force per unit area is significantly increased compared to the previous study reported by Choi (one of the authors). This suggests that the proposed bipolar ESC device has great potential for use in various industries.
{"title":"Development of Bipolar Electrostatic Chuck with a Beam-Array Assembly Fabricated by Lithography","authors":"Y. Taoka, Kohei Kawabata, P. Hemthavy, Seungman Choi, Kunio Takahashi, S. Saito","doi":"10.20965/ijat.2022.p0471","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0471","url":null,"abstract":"This technical paper demonstrates the influence of the probe-tip surface smoothness of a bipolar electrostatic chuck (ESC) on electrostatic force. ESC, which has a silicon-based beam-array microstructure, aims to pick and place a dielectric object with a curved surface owing to the compliance of its elastically deformable beams. The ESC was fabricated using a lithography technique, specifically deep reactive ion etching (DRIE), to smooth the surface of the beam tip. The surface roughness of the beam tips was observed using a field-emission scanning electron microscope (FE-SEM), and the adhesional force was experimentally evaluated. The results show that by the smoothing process, the adhesional force per unit area is significantly increased compared to the previous study reported by Choi (one of the authors). This suggests that the proposed bipolar ESC device has great potential for use in various industries.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"24 1","pages":"471-477"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74322148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.20965/ijat.2022.p0427
Yasukazu Sato, Takeyoshi Shimbori
The use of pneumatics has led to the development of a linear actuator that incorporates pressure-resistant metal bellows. This pressure-resistant bellows device is airtight and capable of considerable expansion. Conventional bellows devices are susceptible to bending stresses at the folds because high air pressure tends to crush the curvature of the bellows there. Therefore, their application only uses a 0.1 MPa difference in inner/outer pressure. The pressure-resistance of the bellows device is improved by the installation of viscoelastic rings in its folds, rings which reduce the bending stress caused by the high air pressure at the thin-walled inner folds. As a result, the pressure resistance is increased by 0.7 MPa. This paper uses a theoretical formulation and a finite element analysis approach in reporting the improvement in pressure resistance made by the installation of the viscoelastic rings. Furthermore, the actuator with pressure-resistant, thin-walled metal bellows is used to control the posture and damping force of a vehicle’s active suspension.
{"title":"Pneumatically-Controlled Linear Actuator Using Pressure-Resistant, Thin-Walled Metal Bellows and its Application","authors":"Yasukazu Sato, Takeyoshi Shimbori","doi":"10.20965/ijat.2022.p0427","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0427","url":null,"abstract":"The use of pneumatics has led to the development of a linear actuator that incorporates pressure-resistant metal bellows. This pressure-resistant bellows device is airtight and capable of considerable expansion. Conventional bellows devices are susceptible to bending stresses at the folds because high air pressure tends to crush the curvature of the bellows there. Therefore, their application only uses a 0.1 MPa difference in inner/outer pressure. The pressure-resistance of the bellows device is improved by the installation of viscoelastic rings in its folds, rings which reduce the bending stress caused by the high air pressure at the thin-walled inner folds. As a result, the pressure resistance is increased by 0.7 MPa. This paper uses a theoretical formulation and a finite element analysis approach in reporting the improvement in pressure resistance made by the installation of the viscoelastic rings. Furthermore, the actuator with pressure-resistant, thin-walled metal bellows is used to control the posture and damping force of a vehicle’s active suspension.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"33 1","pages":"427-435"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83732235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.20965/ijat.2022.p0489
Kosuke Uchiyama, H. Murakami, A. Katsuki, T. Sajima
This paper presents a system for measuring nanoscale sidewall features using an L-shaped stylus with a sharp tip. By sharpening the tip of the stylus to the nanometer scale, it is possible to measure nanoscale sidewall features. The stylus shaft is deflected when the sharpened stylus tip contacts the measured surface, and this deflection is measured optically. In this study, we develop the fabrication method of an L-shaped sharpened stylus 20 μm in diameter and 4 mm in length by etching, CO2 laser processing, and bonding. Then, the measurement accuracy and repeatability are examined by measuring V-grooves with nanoscale features. The results clarify that the pitch is approximately 0.3 μm, which is almost the same as the value measured using the photographic image, but the depths measured by the styli fabricated by CO2 laser processing and bonding are approximately 0.15 and 0.07 μm, respectively. The depth measured by the stylus fabricated by bonding is smaller than that measured from the image (approximately 0.16 μm), presumably because of the morphological filter. The maximum repeatability errors for 10 measurements using the styli fabricated by CO2 laser processing and bonding are within ±0.056 and ±0.022 μm in scanning mode, respectively. It is also confirmed that the stylus tip exhibits minimal wear even after 500 measurements.
{"title":"Development of a Sharp-Tipped L-Shaped Stylus for Measurement of Nanoscale Sidewall Features","authors":"Kosuke Uchiyama, H. Murakami, A. Katsuki, T. Sajima","doi":"10.20965/ijat.2022.p0489","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0489","url":null,"abstract":"This paper presents a system for measuring nanoscale sidewall features using an L-shaped stylus with a sharp tip. By sharpening the tip of the stylus to the nanometer scale, it is possible to measure nanoscale sidewall features. The stylus shaft is deflected when the sharpened stylus tip contacts the measured surface, and this deflection is measured optically. In this study, we develop the fabrication method of an L-shaped sharpened stylus 20 μm in diameter and 4 mm in length by etching, CO2 laser processing, and bonding. Then, the measurement accuracy and repeatability are examined by measuring V-grooves with nanoscale features. The results clarify that the pitch is approximately 0.3 μm, which is almost the same as the value measured using the photographic image, but the depths measured by the styli fabricated by CO2 laser processing and bonding are approximately 0.15 and 0.07 μm, respectively. The depth measured by the stylus fabricated by bonding is smaller than that measured from the image (approximately 0.16 μm), presumably because of the morphological filter. The maximum repeatability errors for 10 measurements using the styli fabricated by CO2 laser processing and bonding are within ±0.056 and ±0.022 μm in scanning mode, respectively. It is also confirmed that the stylus tip exhibits minimal wear even after 500 measurements.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"34 1","pages":"489-496"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81110928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-05DOI: 10.1299/jsmemecj.2021.s117-02
Yutaka Tanaka, Ryuta X. Suzuki, K. Edamura, S. Yokota
Gripping and holding mechanism of automated systems in manufacturing and distribution industries are required to flexibly accommodate various product shapes. In recent years, the gripping and holding mechanisms using jamming transition have been attracting attention because they can grasp objects of various shapes. The jamming gripping mechanism generally requires a mechanical vacuum pump to adjust the internal pressure of the gripping part, and it is difficult to miniaturize the system. An electro-conjugate fluid (ECF), a type of functional fluid, can generate a strong jet flow by applying a high DC voltage between the positive and negative electrodes. The ECF jet flow has a great potential to realize micro fluid power sources. In this paper, we proposed and prototyped a new type of small gripping and holding mechanism that uses the jet flow generated by the ECF and the jamming of granular material. A prototyped micro gripper had an outer diameter of 14 mm, a total length of 40 mm, and a tip diameter of 10 mm for gripping. A mathematical model of the micro gripper was derived by deformation of an elastic membrane and volume and pressure changes. It was verified by the mathematical model that the supplied pressure of the ECF hydraulic power source was large enough to realize gripping performance of the prototyped jamming gripper. The performance of the prototype micro gripper was numerically and experimentally evaluated the mathematical model. It was experimentally clarified that a maximum holding force of the prototyped jamming gripper was shown under the condition that filling rate of granular material was 50%. It was also clarified that the micro gripper with a built-in vacuum pump using the ECF hydraulic power source had a gripping force of up to 93 mN at an applied DC voltage of 4 kV.
{"title":"Design and Fabrication of Micro Gripper Using Functional Fluid Power","authors":"Yutaka Tanaka, Ryuta X. Suzuki, K. Edamura, S. Yokota","doi":"10.1299/jsmemecj.2021.s117-02","DOIUrl":"https://doi.org/10.1299/jsmemecj.2021.s117-02","url":null,"abstract":"Gripping and holding mechanism of automated systems in manufacturing and distribution industries are required to flexibly accommodate various product shapes. In recent years, the gripping and holding mechanisms using jamming transition have been attracting attention because they can grasp objects of various shapes. The jamming gripping mechanism generally requires a mechanical vacuum pump to adjust the internal pressure of the gripping part, and it is difficult to miniaturize the system. An electro-conjugate fluid (ECF), a type of functional fluid, can generate a strong jet flow by applying a high DC voltage between the positive and negative electrodes. The ECF jet flow has a great potential to realize micro fluid power sources. In this paper, we proposed and prototyped a new type of small gripping and holding mechanism that uses the jet flow generated by the ECF and the jamming of granular material. A prototyped micro gripper had an outer diameter of 14 mm, a total length of 40 mm, and a tip diameter of 10 mm for gripping. A mathematical model of the micro gripper was derived by deformation of an elastic membrane and volume and pressure changes. It was verified by the mathematical model that the supplied pressure of the ECF hydraulic power source was large enough to realize gripping performance of the prototyped jamming gripper. The performance of the prototype micro gripper was numerically and experimentally evaluated the mathematical model. It was experimentally clarified that a maximum holding force of the prototyped jamming gripper was shown under the condition that filling rate of granular material was 50%. It was also clarified that the micro gripper with a built-in vacuum pump using the ECF hydraulic power source had a gripping force of up to 93 mN at an applied DC voltage of 4 kV.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"75 1","pages":"448-455"},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88287693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-05DOI: 10.20965/ijat.2022.p0367
M. Yamashita, Haruki Saito, M. Nikawa
Several types of multiple straight convex shapes were formed on a thin aluminum sheet with a grooved die using impulsive water pressure. The maximum pressure was 160 MPa in the high-speed forming, wherein a drop hammer testing machine was used, whereas it was 100 MPa in the low-speed forming because of the limitations of the press machine. The effects of the forming speed, cross-sectional shape, and pitch of the grooves on the deformation behavior were investigated. The increase in the impulsive water pressure was found to be affected significantly by the compressibility of water. The symmetricity of the convex shape in the cross-section decreased at both ends for a smaller pitch because of the imbalance of the material flow at both peripheries of the groove. The concave surface profile of the pressure side was more rounded in the high-speed forming than that in the low-speed forming when semicircular and rectangular grooved dies were used. This may be attributed to the fact that the plastic deformation becomes more uniform owing to the positive strain rate sensitivity of the test material. In the forming with rectangular grooves, fracture occurred under the low- and high-speed conditions, wherein the maximum pressure was set to 100 MPa. However, the material did not fracture during high-speed forming with a pressure of 160 MPa, where the convex shape was higher and the material contacted the bottom of the groove. This behavior may be because the dislocation density of the material did not increase rapidly owing to the strain rate being maintained high until the material suddenly stopped deforming in the latter condition. In forming with a trapezoidal grooved die, the formed profiles were considerably similar under all conditions because the strain was considerably smaller than that with the other grooves.
{"title":"Forming of Multiple Straight Convex Shapes on Aluminum Sheet Using Impulsive Water Pressure","authors":"M. Yamashita, Haruki Saito, M. Nikawa","doi":"10.20965/ijat.2022.p0367","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0367","url":null,"abstract":"Several types of multiple straight convex shapes were formed on a thin aluminum sheet with a grooved die using impulsive water pressure. The maximum pressure was 160 MPa in the high-speed forming, wherein a drop hammer testing machine was used, whereas it was 100 MPa in the low-speed forming because of the limitations of the press machine. The effects of the forming speed, cross-sectional shape, and pitch of the grooves on the deformation behavior were investigated. The increase in the impulsive water pressure was found to be affected significantly by the compressibility of water. The symmetricity of the convex shape in the cross-section decreased at both ends for a smaller pitch because of the imbalance of the material flow at both peripheries of the groove. The concave surface profile of the pressure side was more rounded in the high-speed forming than that in the low-speed forming when semicircular and rectangular grooved dies were used. This may be attributed to the fact that the plastic deformation becomes more uniform owing to the positive strain rate sensitivity of the test material. In the forming with rectangular grooves, fracture occurred under the low- and high-speed conditions, wherein the maximum pressure was set to 100 MPa. However, the material did not fracture during high-speed forming with a pressure of 160 MPa, where the convex shape was higher and the material contacted the bottom of the groove. This behavior may be because the dislocation density of the material did not increase rapidly owing to the strain rate being maintained high until the material suddenly stopped deforming in the latter condition. In forming with a trapezoidal grooved die, the formed profiles were considerably similar under all conditions because the strain was considerably smaller than that with the other grooves.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"92 1","pages":"367-373"},"PeriodicalIF":0.0,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75633039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-05DOI: 10.20965/ijat.2022.p0296
S. Salama, T. Kaihara, N. Fujii, D. Kokuryo
The goal of the Fourth Industrial Revolution is to develop smart factories that ensure flexibility and adaptability in complex production environments, without human intervention. Smart factories are based on three main pillars: integration through digitalization, employment of flexible structures, and the use of artificial intelligence (AI) methods. Genetic programming (GP) is one of the most promising AI approaches used in the automated design of production-scheduling rules. However, promoting diversity and controlling the bloating effect are major challenges to the success of GP algorithms in developing production-scheduling rules that deliver high-quality solutions. Therefore, we introduced a multi-objective technique to increase the diversity among GP individuals while considering the program length as an objective to avoid the bloating effect. The proposed approach employs a new diversity metric to measure the distance between GP individuals and the best rule in the current generation. Subsequently, the non-dominated sorting genetic algorithm II (NSGA-II) was used to select individuals based on three objectives: solution quality, similarity value, and program length. To assess the effectiveness of the proposed approach, we compare the two versions with three GP methods in the literature in terms of automatically generating dispatching rules on 10 benchmark instances of the job-shop scheduling problem. The experimental results show that the proposed distance measure enhances the phenotypic diversity of individuals, resulting in improved fitness values without the need for additional fitness assessments. In addition, the integration of NSGA-II with the GP algorithm facilitates the evolution of superior job shop dispatching rules with high diversity and shorter lengths under the makespan and mean tardiness objectives.
第四次工业革命的目标是开发智能工厂，确保在复杂的生产环境中具有灵活性和适应性，而无需人为干预。智能工厂基于三个主要支柱:数字化集成，灵活结构的使用以及人工智能(AI)方法的使用。遗传规划(GP)是用于生产调度规则自动化设计的最有前途的人工智能方法之一。然而，促进多样性和控制膨胀效应是GP算法在制定高质量解决方案的生产调度规则方面取得成功的主要挑战。因此，我们引入了一种多目标技术，以增加GP个体之间的多样性，同时考虑程序长度作为目标，以避免腹胀效应。该方法采用一种新的多样性度量来衡量GP个体与当前代最佳规则之间的距离。随后，采用非支配排序遗传算法II (non- dominant sorting genetic algorithm II, NSGA-II)，根据解质量、相似度值和程序长度三个目标进行个体选择。为了评估所提出方法的有效性，我们将这两个版本与文献中的三种GP方法在10个作业车间调度问题基准实例上自动生成调度规则方面进行了比较。实验结果表明，所提出的距离度量增强了个体的表型多样性，从而在不需要额外适应度评估的情况下提高了适应度值。此外，将NSGA-II与GP算法相结合，有利于在最大完工时间和平均延迟目标下演化出多样性高、长度短的优作业车间调度规则。
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Pub Date : 2022-05-05DOI: 10.20965/ijat.2022.p0329
A. Iqbal, N. S. Mian, A. Longstaff, S. Fletcher
The recent development of low-cost accelerometers, driven by the Industrial Internet of Things (IIoT) revolution, provides an opportunity for their application in precision manufacturing. Sensor data is often of the highest consideration in any precision machining process. While high-cost vibration sensors have traditionally been employed for vibration measurements in industrial manufacturing, the measurement uncertainty affecting the accuracy of low-cost vibration sensors has not been explored and requires performance evaluation. This research focuses on the characterization of measurements from low-cost tri-axial micro electro-mechanical systems (MEMS) accelerometers in terms of identifying the parameters that induce uncertainties in measured data. Static and dynamic calibration was conducted on a calibration test bench using a range of frequencies while establishing traceability according to the ISO 16063 series and the IEEE-STD-1293-2018 standards. Moreover, comparison tests were performed by installing the sensors on machine tools for reliability evaluation in terms of digital transmission of recorded data. Both tests further established the relationship between the baseline errors originating from the sensors and their influence on the data obtained during the dynamic performance profile of the machine tools. The outcomes of this research will foresee the viability offered by such low-cost sensors in metrological applications enabling Industry 4.0.
{"title":"Performance Evaluation of Low-Cost Vibration Sensors in Industrial IoT Applications","authors":"A. Iqbal, N. S. Mian, A. Longstaff, S. Fletcher","doi":"10.20965/ijat.2022.p0329","DOIUrl":"https://doi.org/10.20965/ijat.2022.p0329","url":null,"abstract":"The recent development of low-cost accelerometers, driven by the Industrial Internet of Things (IIoT) revolution, provides an opportunity for their application in precision manufacturing. Sensor data is often of the highest consideration in any precision machining process. While high-cost vibration sensors have traditionally been employed for vibration measurements in industrial manufacturing, the measurement uncertainty affecting the accuracy of low-cost vibration sensors has not been explored and requires performance evaluation. This research focuses on the characterization of measurements from low-cost tri-axial micro electro-mechanical systems (MEMS) accelerometers in terms of identifying the parameters that induce uncertainties in measured data. Static and dynamic calibration was conducted on a calibration test bench using a range of frequencies while establishing traceability according to the ISO 16063 series and the IEEE-STD-1293-2018 standards. Moreover, comparison tests were performed by installing the sensors on machine tools for reliability evaluation in terms of digital transmission of recorded data. Both tests further established the relationship between the baseline errors originating from the sensors and their influence on the data obtained during the dynamic performance profile of the machine tools. The outcomes of this research will foresee the viability offered by such low-cost sensors in metrological applications enabling Industry 4.0.","PeriodicalId":13583,"journal":{"name":"Int. J. Autom. Technol.","volume":"14 1","pages":"329-339"},"PeriodicalIF":0.0,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81982458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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