Key Engineering Materials Vol. 613

Abstract: Principles of uncertainty evaluation for measurement processes and capability studies for production processes have been known for several years and are established in many producing enterprises where they ensure capable and controlled processes. The ability to quantify the processes risk is also desirable for a completely different field, for medical surgery. Especially for new and minimally invasive surgery it is very important to estimate and state the risk of the surgical intervention for the individual patient. To achieve this, principles of metrology and production engineering are transferred to the medical domain and are exemplarily applied for minimally invasive surgery at the inner ear. The contribution shows how the individual patients risk can be expressed analogous to the calculation of capability indices (ISO 22514-1) and how the patients risk for this intervention is directly affected by uncertainty contributions along the surgical process chain.

Abstract: The occurrence of thermal drift in industrial computed tomography (CT) systems has been reported as a significant source of error on geometrical evaluations. During CT-scans, heating inside the cabinet and varying environmental conditions may affect the position of the focal spot and distort the manipulator system, leading to relative displacement of X-ray projections and distortions in the reconstructed 3D image. This paper presents an experimental investigation on influence of the thermal effects on dimensional CT measurements. A correction method based on the manipulation of the projections was developed and evaluated. The method consists in repeating the acquisition of first projection at the end of the scan and calculating the displacement vector between these projections. The remaining projections are then corrected proportionally to this displacement. The results showed a significant reduction of the roundness deviation values measured on a precision sphere after the correction.

Abstract: X-ray computed tomography, first conceived to image internal structures of the human body, has become an important metrology technique for material quality control and dimensional quality control. As a material quality control tool, discontinuities, cracks and voids can be detected without physically destroying or damage the sample under analysis. As a dimensional metrology technique, the complete examination in a non-destructive manner of inner and outer geometries of parts and components has become possible. In this paper, material investigation of connecting rods manufactured through both casting and forging processes and dimensional evaluation of intricate geometries found on connecting rods are described and discussed from the metrology point of view.

Abstract: Long-lasting works on the ISO 15530 series can be a proof for complexity of uncertainty evaluation of coordinate measurements for different characteristics defined according to the rules of geometrical product specification (GPS). Even the best known procedures (using the calibrated workpiece and using computer simulation) have not been implemented widely. The authors have elaborated the methodology and the software (EMU-CMMUncertainty^TM) which makes possible evaluation of the measurement uncertainty with less effort. The software has been developed with following assumptions. Uncertainty budget includes influences of particular geometrical errors of the CMM, probing system errors as well as temperature errors. Applied algorithms use type B method according to the rules of GUM. Uncertainty is analysed separately for each characteristic (task-specific approach). Uncertainty of measurement for particular characteristic is calculated with the formula describing the characteristic as a function of differences of coordinates of characteristic points of the workpiece. The paper presents some new details concerning formulation of uncertainty budget. Among others the methodology is presented for estimation of uncertainty component arising from the fact that some characteristic points are not integral features (surface points) but derived features (axes points).

Abstract: Calculations of capability and performance indices are based on measurement results. The uncertainty of the measurement process used to generate capability and performance indices must be estimated before the indices can be meaningful. The actual measurement uncertainty needs to be adequately small.To demonstrate the suitability of measurement processes, were in the industrial production process based on the MSA version 4 (AIAG Measurement System Analysis [) is used.Another procedure is based on the ISO 98-3 ISO; Guide to the Expression of Uncertainty in Measurement (GUM) [. But this is not practical in production. Therefore, the ISO 22514-7 [ was published. This document is in the FDIS (Final Draft ISO) status and will be official until mid-2012 as an ISO Standard. The VDA 5; Measurement Process Capability [ is also based on this new standard

Abstract: Transportation simulations are an important part of today’s decision making process for transport infrastructure and management. While proposed changes are getting more and more complex, tools supporting the decision making process are struggling to keep up. Traditional, flow-based traffic assignment tools are limited in the number of different person groups that can be distinguished and do in most cases not offer fully time-dynamic results. Newer technologies like agent-based simulations overcome those problems. This paper presents a novel traffic simulation scheme capable of modeling chaotic motorway traffic. Different from other lane-based or following-based approaches, the proposed approach models traffic as a large navigational problem in an agent based simulation context. In addition, the approach is efficiently able to handle hard cases like overtaking, behavior at turning and aggressive driving behavior. The simulation was demonstrated at real-time rates using MATSim applied to Cairo Ring Road. It has been described as well how MATSim simulation was extended to incorporate aggressive and careless drivers' behavior.

Abstract: Solar proton event is one of the important sources of interference, which may cause perturbations of the Sun-earth system in a great contingency. Big levels of proton events can also affect the reliability of carrier laboratory equipment in space station. The safe operation of on-orbit space station may be threatened at sometimes. This paper presents a new method to predict the probability of occurrence and estimate the level of proton events based on grey relational analysis and joint probability density forecast. Firstly, the grey relational analysis is applied to extract the most relevant data sequences from numerous related characteristic quantities which characterize events occurrence. Secondly, the characteristic data sequences are made to be dimensionless and the dimensions are compressed. After the sequences of characteristic factors are recombined, the new independent integrated variables can be generated. Finally, the GM(1,N) prediction model for the present and absent event established. At the same time, the joint probability density method is used to analyse the optimized characteristic factor sequence, the joint probability density model of different levels of proton events corresponding characteristic factors can also be obtained. The combination of the model and setting event level threshold value are obtained, and the joint probability density discriminator is constituted. The level of impending proton event is predicted by utilizing the discriminator. The results show that the event predictive precision rate is prior to 90% by selecting the data of solar proton events occuring in 2012 for model prediction, and the prediction accuracy of events level is superior to 85%.

Abstract: The MICROSCOPE (MicroSatellite à traînée Compensée pour l'Observation du Principe d'Equivalence) project is an orbit-based mission to verify the Weak Equivalent Principle with an uncertainty of 10-15. To achieve this goal two differential accelerometer, each equipped with two high precision test masses (made of PtRh10 and TiAl6V4 in the form of hollow cylinders with four flats at the outer shell and six precision countersinks at each face), are to be launched in Spring 2016 and shall orbit the earth for approx. one and a half year.

Abstract: A system for measuring the rail profiles of a long hydrostatic guideway is proposed and applied to a precision roll lathe. The rail profiles, consisting of rail form errors and a parallelism error, are measured with four capacitive probes placed on the two rail surfaces, and a laser interferometer with angular optics. The form error of each rail is measured using a mixed sequential two-probe method, while the parallelism error between the rails is measured with two opposing capacitive probes. To eliminate the necessity for additional guidance mechanisms, theprobe table is guided by air bearings and the rails being measured. To verify the measurement results, two self-verification techniques are suggested and tested. Firstly, the linear motion errors of the probe table on the two rails are compared, yielding a difference of 0.79 μm in 2σ. Secondly, the sum of the rail form errors is compared with the slope-removed sum of the two capacitive probes used for the parallelism measurement, yielding a difference of 0.81 μm in 2σ. According to the self-verification results, the accuracy of the proposed measurement method is about 1 μm for a rail length of 2,825 mm.

Abstract: Laser beam precision control in ultro-precision manufacturing or other applications is to manipulate the beam pointing, intensity distribution, shape, far field patterns and so on. The method of beam control we used is different from traditional way that with mechanical inertia parts. The Liquid Crystal Spacial Light Modulator (LCSLM) is an electronic controlled, programmable diffractive device, which is able to modulate the phase of incident beam, therefore generate the objective patterns in far field. To establish the relationship between phase distribution of LCSLM and the far field objective function that represents the requirement of application, FFT and improved G-S algorithm are employed. Multi-beam focal point 3D control, beam shaping from Gaussian distribution to square and annular distribution with flat-top are discussed. They were studied in both theoretical and experimental ways. The results are evaluated by using error of root mean square and diffraction efficiency, which are less than 1% and higher than 90%, respectively.