In-process calibration of smart structures produced by incremental forming

AbstractSmart load-bearing structures are created by forming integration of functional materials into passive metallic components with target-oriented pre-stress conditions by rotary swaging. Their sensory capability cannot only be used during the utilization but also during the manufacturing phase. Previous works demonstrated how this capability paves the way for efficient monitoring and controlling of the used integration process. In search of an even higher overall efficiency of the manufacturing chain, the subsequent costly calibration step deserves closer attention. Therefore, a cost- and time-efficient approach for the process-integrated calibration of a sensor-integrated structure is proposed in this paper. During the in-process calibration, the acting process forces are measured both in the integrated sensor and in a special-built clamping fixture. The measured data can be transferred into calibration slopes of the sensory structures. A suitable signal processing based on the process characteristics is performed to compensate interference effects on the raw signals. As a result, an accuracy of the calibration better than 2% of the nominal value compared to an offline standardized calibration is achieved with the in-line calibration method. Consequently, efficiency in the manufacturing of sensory structures is further boosted by avoidance of setup or logistical operations.

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CALIBRATION OF THE SR4500 TIME-OF-FLIGHT CAMERA FOR OUTDOOR MOBILE SURVEYING APPLICATIONS: A CASE STUDY

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xli-b5-469-2016 ◽

2016 ◽

Vol XLI-B5 ◽

pp. 469-476

Author(s):

C. Heinkelé ◽

M. Labbé ◽

V. Muzet ◽

P. Charbonnier

Keyword(s):

Time Of Flight ◽

Calibration Method ◽

Internal Calibration ◽

Common Basis ◽

Calibration And Measurement Capabilities ◽

Tof Camera ◽

Calibration Step ◽

Measurement Capabilities ◽

Better Than

3D-cameras based on Time-of-Flight (ToF) technology have recently raised up to a commercial level of development. In this contribution, we investigate the outdoor calibration and measurement capabilities of the SR4500 ToF camera. The proposed calibration method combines up-to-date techniques with robust estimation. First, intrinsic camera parameters are estimated, which allows converting radial distances into orthogonal ones. The latter are then calibrated using successive acquisitions of a plane at different camera positions, measured by tacheometric techniques. This distance calibration step estimates two coefficient matrices for each pixel, using linear regression. Experimental assessments carried out with a 3D laser-cloud after converting all the data in a common basis show that the obtained precision is twice better than with the constructor default calibration, with a full-frame accuracy of about 4 cm. Moreover, estimating the internal calibration in sunny and warm outdoor conditions yields almost the same coefficients as indoors. Finally, a test shows the feasibility of dynamic outdoor acquisitions and measurements.

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CALIBRATION OF THE SR4500 TIME-OF-FLIGHT CAMERA FOR OUTDOOR MOBILE SURVEYING APPLICATIONS: A CASE STUDY

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b5-469-2016 ◽

2016 ◽

Vol XLI-B5 ◽

pp. 469-476 ◽

Cited By ~ 1

Author(s):

C. Heinkelé ◽

M. Labbé ◽

V. Muzet ◽

P. Charbonnier

Keyword(s):

Time Of Flight ◽

Calibration Method ◽

Internal Calibration ◽

Common Basis ◽

Calibration And Measurement Capabilities ◽

Tof Camera ◽

Calibration Step ◽

Measurement Capabilities ◽

Better Than

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Calibration of pneumotachographs using a calibrated syringe

Journal of Applied Physiology ◽

10.1152/japplphysiol.00196.2003 ◽

2003 ◽

Vol 95 (2) ◽

pp. 571-576 ◽

Cited By ~ 14

Author(s):

Yongquan Tang ◽

Martin J. Turner ◽

Johnny S. Yem ◽

A. Barry Baker

Keyword(s):

Calibration Method ◽

Linear Range ◽

Data Sets ◽

Constant Flow ◽

Calibration Constant ◽

Third Order ◽

Polynomial Coefficients ◽

Calibration Curves ◽

Order Polynomial ◽

Better Than

Pneumotachograph require frequent calibration. Constant-flow methods allow polynomial calibration curves to be derived but are time consuming. The iterative syringe stroke technique is moderately efficient but results in discontinuous conductance arrays. This study investigated the derivation of first-, second-, and third-order polynomial calibration curves from 6 to 50 strokes of a calibration syringe. We used multiple linear regression to derive first-, second-, and third-order polynomial coefficients from two sets of 6–50 syringe strokes. In part A, peak flows did not exceed the specified linear range of the pneumotachograph, whereas flows in part B peaked at 160% of the maximum linear range. Conductance arrays were derived from the same data sets by using a published algorithm. Volume errors of the calibration strokes and of separate sets of 70 validation strokes ( part A) and 140 validation strokes ( part B) were calculated by using the polynomials and conductance arrays. Second- and third-order polynomials derived from 10 calibration strokes achieved volume variability equal to or better than conductance arrays derived from 50 strokes. We found that evaluation of conductance arrays using the calibration syringe strokes yields falsely low volume variances. We conclude that accurate polynomial curves can be derived from as few as 10 syringe strokes, and the new polynomial calibration method is substantially more time efficient than previously published conductance methods.

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Formation Of Two-Dimensional Photonic Crystals With Cavities Arrays In Silicon

Siberian Journal of Physics ◽

10.54362/1818-7919-2016-11-1-88-93 ◽

2016 ◽

Vol 11 (1) ◽

pp. 88-93

Author(s):

Dmitriy Utkin ◽

Aleksandr Shklyaev ◽

Fedor Dultsev ◽

Aleksandr Latyshev

Keyword(s):

Electron Beam ◽

Photonic Crystals ◽

Electron Beam Lithography ◽

Spatial Distributions ◽

Two Dimensional ◽

Interference Effects ◽

Technological Parameters ◽

Beam Interaction ◽

Cavity Array ◽

Better Than

Specific aspects of finely focused electron beam interaction with the PMMA-950K resist for the fabrication of closely spaced holes having inhomogeneous spatial distributions are studied. The technological parameters for the creation of two-dimensional photonic crystals with microcavities (missing holes) arrays, which allow obtaining the lateral sizes of the structure within the accuracy better than 2 %, in silicon using electron-beam lithography are determined. Such holes fabrication accuracy is thought to be sufficient to study the interference effects of cavity array radiation in twodimensional photonic crystals.

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Charuco Board-Based Omnidirectional Camera Calibration Method

Electronics ◽

10.3390/electronics7120421 ◽

2018 ◽

Vol 7 (12) ◽

pp. 421 ◽

Cited By ~ 11

Author(s):

Gwon An ◽

Siyeong Lee ◽

Min-Woo Seo ◽

Kugjin Yun ◽

Won-Sik Cheong ◽

...

Keyword(s):

Camera Calibration ◽

Mean Absolute Error ◽

Three Dimensional ◽

Absolute Error ◽

Calibration Method ◽

Feature Points ◽

Omnidirectional Camera ◽

Reprojection Error ◽

Conventional Methods ◽

Better Than

In this paper, we propose a Charuco board-based omnidirectional camera calibration method to solve the problem of conventional methods requiring overly complicated calibration procedures. Specifically, the proposed method can easily and precisely provide two-dimensional and three-dimensional coordinates of patterned feature points by arranging the omnidirectional camera in the Charuco board-based cube structure. Then, using the coordinate information of the feature points, an intrinsic calibration of each camera constituting the omnidirectional camera can be performed by estimating the perspective projection matrix. Furthermore, without an additional calibration structure, an extrinsic calibration of each camera can be performed, even though only part of the calibration structure is included in the captured image. Compared to conventional methods, the proposed method exhibits increased reliability, because it does not require additional adjustments to the mirror angle or the positions of several pattern boards. Moreover, the proposed method calibrates independently, regardless of the number of cameras comprising the omnidirectional camera or the camera rig structure. In the experimental results, for the intrinsic parameters, the proposed method yielded an average reprojection error of 0.37 pixels, which was better than that of conventional methods. For the extrinsic parameters, the proposed method had a mean absolute error of 0.90° for rotation displacement and a mean absolute error of 1.32 mm for translation displacement.

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Experimental Study of Failure Modes and Scaling Effects in Micro-Incremental Forming

Journal of Micro and Nano-Manufacturing ◽

10.1115/1.4025098 ◽

2013 ◽

Vol 1 (3) ◽

Cited By ~ 7

Author(s):

Michael Beltran ◽

Rajiv Malhotra ◽

A. J. Nelson ◽

Anirban Bhattacharya ◽

N. V. Reddy ◽

...

Keyword(s):

Failure Modes ◽

Incremental Forming ◽

Three Dimensional ◽

Forming Limit ◽

Scaling Effects ◽

Forming Process ◽

Material Microstructure ◽

Buckling Mode ◽

Ideal Candidate ◽

Process Characteristics

Incremental forming (IF) is a relatively new technique that uses a simple hemispherical ended tool moving along a predefined three-dimensional toolpath to deform a sheet of metal into the desired shape. The greater process flexibility and higher formability in IF have resulted in greater academic and industrial interest in this process as it can successfully produce ultrathin parts beyond the forming limit seen in conventional stamping and the process does not require any geometry-specific tooling. Another emerging paradigm in manufacturing has been the increasing application of forming in micromanufacturing. The above stated process characteristics of IF make it an ideal candidate for being incorporated into the micromanufacturing paradigm. This work investigates micro-IF to examine how forces and occurrence of sheet failure change when the geometric dimensions of incremental forming are scaled down. The development of a highly repeatable micro-IF experimental setup is described and experiments are performed to show that a previously unknown buckling mode of deformation exists in micro-incremental forming, that is linked to the material microstructure. The analysis provides guidelines for the design and understanding of the micro-incremental forming process.

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Forecasting of an extreme flood in mountainous area of North China based on WRF-Hydro with distributing parameters

10.5194/egusphere-egu2020-21037 ◽

2020 ◽

Author(s):

Wei Wang ◽

JIa Liu ◽

Chuanzhe Li ◽

Qingtai Qiu ◽

Yuchen Liu

Keyword(s):

Extreme Event ◽

Forecast Accuracy ◽

Northern China ◽

Calibration Method ◽

Mountainous Area ◽

Coupling System ◽

Extreme Flood ◽

Spatio Temporal ◽

Merging Method ◽

Better Than

The flood events in the mountainous area of northern China has the characteristics of high intensity and strong sudden occurrence, and atmospheric-hydrological coupling system can improve the forecast accuracy and prolong the lead time. This paper discusses the simulations of the enhanced WRF-Hydro model on a historical flood that occurrs in a mesoscale catchment of Taihang mountain on July 21, 2012. Firstly, the precipitation accuracy of WRF, WRF data assimilation, co-kriging merging method of radar QPE data are as three different input sources for WRF-Hydro. The results show that the rainfall of merging QPE can achieve better simulations in time and space. In addition, the rainfall of WRF assimilation data is obviously better than that of WRF, but still underestimates the rainfall values. The extreme event rainstorm mainly proceeds&#160;in 5 hours, and for the assimilation data, the spatio-temporal simulations of the rainfall data in the first 2 hours are slightly poor. Hence we compare the combination of the first few hours to use the merging QPE and following by assimilation precipitation as the model input. In addition, according to the parameters of the WRF-Hydro model, a gridding parameter calibration method based on topographic index is constructed.

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CALIBRATION STUDY OF A TRIMBLE ACx4 SYSTEM FOR DIRECT GEOREFERENCING MAPPING APPLICATIONS

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-iv-1-45-2018 ◽

2018 ◽

Vol IV-1 ◽

pp. 45-52

Author(s):

L. E. Filho ◽

E. A. Mitishita

Keyword(s):

Large Scale ◽

Calibration Method ◽

Relative Orientation ◽

Aerial Images ◽

Synthetic Image ◽

Integrated Sensor ◽

Full Field ◽

System Calibration ◽

Simultaneous Acquisition ◽

Sensor Orientation

Abstract. The Trimble Aerial Camera x4 (i.e., TACx4) is a photogrammetric multi-head system manufactured by Trimble Inc.&copy; in 2010. It has four cameras mounted together in the main structure allowing the simultaneous acquisition to generate a single synthetic image with much larger ground coverage. In addition, the cameras are also integrated with a GNSS/INS to perform “Direct” or “Integrated” Sensor Orientation. The main condition to obtain photogrammetric mapping products with high accuracy using a direct sensor orientation procedure is to execute a step known as “geometric system calibration”. In general, the photogrammetric multi-head system manufacturers perform this step using laboratory methods to obtain the parameters of cameras interior and relative orientation. Accurate mounting parameters (lever arms and “boresight misalignments”) are fundamental requirements to generate the synthetic image when georeferencing of images is applied. This paper shows a “full field” calibration method to perform the geometric system calibration of the TACx4 system and its evaluation for direct sensor orientation mapping applications. The developed method involves two steps using only aerial images: (1) estimation of the cameras interior and relative orientation parameters to generate the synthetic image and (2) estimation of the synthetic image interior orientation and the mounting parameters between the synthetic image and GNSS/INS reference systems using two different methods. The obtained results in the conventional photogrammetric project show that the proposed method allows performing the geometric system calibration of the TACx4 system achieving around 50cm (5 pixels) in horizontal and vertical accuracies. The obtained results can be used for large-scale mapping requirements using direct sensor orientation according to Brazilian accuracy standards.

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Adaption of Functional Ceramic Materials for the Laser Sintering Process in Integrated Sensor Applications

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/2016cicmt-ta14 ◽

2016 ◽

Vol 2016 (CICMT) ◽

pp. 000011-000017

Author(s):

Rena Gradmann ◽

Thomas Seuthe ◽

Christian Vedder ◽

Markus Eberstein ◽

Uwe Partsch

Keyword(s):

Functional Materials ◽

Ceramic Materials ◽

Laser Sintering ◽

Temperature Sensitive ◽

Integrated Sensor ◽

Sensor Applications ◽

Material Optimization ◽

Furnace Sintering ◽

Application Requirements ◽

Functional Ceramic

Abstract The ceramic thick-film technology allows the build-up of miniaturised and robust integrated multilayer-circuits and sensors by means of sequential screen-printing and firing of different functional materials. However, the manufacturing of integrated electronics does not succeed if the components are temperature sensitive or too large for the process in a sintering furnace. At present, large components like wind power rotors, axles or roller bearings are monitored by vulnerable hybrid sensor systems. In order to implement the advantages of integrated devices, like the direct surface contact and the high thermomechanical stability, functional ceramic-based materials are adapted or newly developed to accommodate the needs of laser sintering techniques of printed sensor layers on structural components. In a first approach, screen printed thick films on steel components are investigated. The defect-free densification of functional layers crucially depends on the particular material composition in combination with adapted laser treatment. A first generation of functional layers is presented, comprising isolating, conductive, and resistive electrical materials. The films are tested in demonstrator setups and show functional properties comparable to those of the furnace sintering technology. Future aspects of material optimization and the adaption to specific application requirements will be discussed.

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Incremental Forming: An Innovative Process for Small Batch Production

Materials Science Forum ◽

10.4028/www.scientific.net/msf.729.85 ◽

2012 ◽

Vol 729 ◽

pp. 85-90 ◽

Cited By ~ 1

Author(s):

Miklos Tisza ◽

Péter Zoltán Kovács ◽

Zsolt Lukács

Keyword(s):

Sheet Metal ◽

Sheet Metal Forming ◽

Metal Forming ◽

Incremental Forming ◽

Main Process ◽

Batch Production ◽

General Overview ◽

Process Characteristics ◽

Innovative Process ◽

Incremental Sheet Metal Forming

The need for flexible forming processes is of utmost importance in the recent years. Therefore, it is very important to develop new innovative technologies and processes. This is particularly valid for small batch and prototype production. Incremental sheet metal forming may be regarded as one of the promising developments for these purposes. In this paper, first a general overview of main process characteristics of the incremental sheet metal forming will be given. Then some recent results of a joint Eureka project launched by two universities and two SME companies in Hungary and Slovenia will be presented.

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