Non-contact Measurement Device Research Articles

Research on RBF neural network adaptive control of three-point contactless measuring device for CNC roller grinder

Abstract In order to improve the CNC roll grinder production efficiency, a novel three-point non-contact measurement device is proposed. An adaptive back-stepping control system that combines with a radial basis function neural network (RBFNN) was designed to control the measurement device working position and also to track the periodic reference movement trajectory. In the proposed control system, the RBFNN approximation and tracking ability are used to identify the unknown measuring device dynamic information. Then, the Lyapunov stability theorem is used to derive the adaptive online learning algorithm. All control algorithms are placed in the control chip based on the TMS320F28335 archive. The simulation results show that the proposed control system has a good control effect when applied to the three-point non-contact measuring device in CNC roll grinders.

Geriatric Care Management System Powered by the IoT and Computer Vision Techniques.

The digitalisation of geriatric care refers to the use of emerging technologies to manage and provide person-centered care to the elderly by collecting patients' data electronically and using them to streamline the care process, which improves the overall quality, accuracy, and efficiency of healthcare. In many countries, healthcare providers still rely on the manual measurement of bioparameters, inconsistent monitoring, and paper-based care plans to manage and deliver care to elderly patients. This can lead to a number of problems, including incomplete and inaccurate record-keeping, errors, and delays in identifying and resolving health problems. The purpose of this study is to develop a geriatric care management system that combines signals from various wearable sensors, noncontact measurement devices, and image recognition techniques to monitor and detect changes in the health status of a person. The system relies on deep learning algorithms and the Internet of Things (IoT) to identify the patient and their six most pertinent poses. In addition, the algorithm has been developed to monitor changes in the patient's position over a longer period of time, which could be important for detecting health problems in a timely manner and taking appropriate measures. Finally, based on expert knowledge and a priori rules integrated in a decision tree-based model, the automated final decision on the status of nursing care plan is generated to support nursing staff.

A Real-time Video Measurement System for Quality Control Applications

Quality control is extremely important for manufacturing compatible parts to supply products that meet production requirements. It provides to track and control the stages of the process and minimizes waste by supporting high levels of productivity. Most of the manufacturers prefer a video measurement system (VMS), which offers non-contact high accurate measurement devices, for evaluating machined parts and products. However, due to the advanced technology and low competition the cost of the non-contact measurement devices is high. Besides some facilities and some research laboratories couldn’t reach these high-cost devices. Today, with the help of evolving technology and open-source image processing libraries, it is possible to offer cost-effective and accurate non-contact measurement systems. This study aims to put forward a VMS to measure parts/products in two dimensions with swift and accurate results. The proposed system has an error below 1% and the linear regression coefficient (r2) was found over 0.95. It works in real-time and minimum frequency was found 10 Hz for repetitive measurements, real-time measurement applications. The proposed cost-effective device can be adapted into various quality control applications in industrial manufacturing

0346 Differentiation of Naturalistic Sleep in Chronic Insomnia vs. Healthy Controls Using a Non-Contact Measurement Device

Abstract Introduction Individuals with insomnia report poor sleep quality and non-restorative sleep, and often exhibit irregular sleep patterns over time. First night effects and logistical challenges make it difficult to accurately measure these sleep characteristics in the laboratory. Also, sensitivity to sleep disruption from obtrusive devices confounds sleep measurements in people with insomnia in their naturalistic setting. Non-contact devices (NCDs) may address these issues and enable ecologically valid, longitudinal and unobtrusive characterization of sleep in individuals with insomnia. We present results from a NCD, previously validated against polysomnography, – SleepScore Max (SleepScore Labs) – assessing the sleep of individuals with chronic insomnia, compared to healthy sleeper controls, in their home setting. Methods A total of 112 individuals participated in an at-home sleep monitoring study including 83 with chronic insomnia (ages 19-65, 58 females) and 29 healthy sleeper controls (ages 19-54, 21 females). Enrollment criteria included being 18-65 years of age and, for the insomnia group, meeting International Classification of Sleep Disorders (3rd edition; ICSD-3) criteria for chronic insomnia with no other clinically relevant condition contributing to sleep disturbance. Participants used the NCD to record their sleep periods each night for 8 weeks. Sleep measurements were analyzed for group differences in both means (characterizing sleep overall) and within-subject standard deviations (characterizing night-to-night sleep variability), using mixed-effects regression controlling for systematic between-subject differences. Results On average, individuals with chronic insomnia exhibited increased total wake time, wake after sleep onset, and decreased sleep efficiency relative to healthy sleeper controls (F>6.8, p<0.01). Additionally, they demonstrated greater night-to-night variability in time in bed, total sleep time, sleep latency, total wake time, wakefulness after sleep onset, sleep interruptions, sleep efficiency, and light and deep sleep (F>4.4, p<0.05). Conclusion In our sample of individuals with chronic insomnia, a NCD naturalistically detected differences from healthy sleeper controls in multiple sleep parameters, both on average and in terms of night-to-night variability. Capturing night-to-night variability in the home setting adds an important dimension to our understanding of poor sleep and provides a more comprehensive, ecologically valid characterization of chronic insomnia as experienced in daily life. Support (If Any) NIH grant KL2TR002317; research devices provided by SleepScore Labs

Rancang Bangun Pengukur Detak Jantung Non Kontak Menggunakan Pencitraan Termal untuk Robot Security

In pandemic conditions such as COVID-19, the measurement of vital signs such as body temperature and heart rate becomes the basis for conducting health screenings. To reduce physical contact and potential hazards, this measurement process can be carried out non-contact. The non-contact measurements carried out in this study used a thermal imaging approach. To reduce the potential danger of transmission, this non-contact measurement device is applied to a security robot. The non-contact measurement method using thermal imaging is done by processing a thermal image on the forehead area. Changes in temperature in the forehead area are then entered into a bandpass filter with a frequency of 0.75 Hz to 3 Hz, which is the frequency range of the human heartbeat under normal circumstances. Calculating heart rate is carried out with two approaches, namely peak to peak interval and fast Fourier transform. Based on the peak-to-peak interval approach, the accuracy is 89.24%, with a standard deviation of 5.6. Meanwhile, with the dominant frequency detection approach using the fast Fourier transform, the accuracy value is slightly better, at 91.84%, with a standard deviation of 4.81.

A robust and efficient calibration method for spot laser probe on CMM

Among all the non-contact measurement devices, the spot laser probe achieves a good balance between accuracy and efficiency. When the laser probe is applied to three-dimensional (3-D) measurement, the laser beam direction is essential to transform the probe indication from 1-D distance information into a 3-D vector representing differences in space coordinates. In this article, a calibration method is proposed for the laser probe mounted on the coordinate measuring machine (CMM). During the calibration procedure, the CMM moves along the user-planned path and hundreds of points are scanned in a few seconds. In order to get an accurate laser beam direction estimate, we refine the original inaccurate direction, which is specified by the mechanical structure of the probe fixture, by mapping the scanned points into a sphere. The simulation and experiment manifest that the proposed method is superior to the existing methods and meets the requirement of the micron-level measurement.

Optimization of the GPU-based data evaluation for the low coherence interferometry

Abstract Optical interferometers as non-contact measurement devices are very desirable for the measurement of surface roughness and topography. Compared to phase shifting interferometers (PSIs) with a limited measurement range and a scan step of maximum λ/4, the optical interferometers like low coherence interferometers (LCIs) evaluating the degree of fringe coherence allow a larger vertical measurement range. Their vertical measurement range is only limited by the scan length allowed by the linear piezo stage and the coherence length of the light source. To evaluate the obtained data for a large range, the common LCIs require much computation time. To overcome this drawback, we present an evaluation algorithm based on the Hilbert-Transform and curve fitting (Levenberg–Marquardt algorithm) using Compute Unified Device Architecture (CUDA) technology, which allows parallel and independent data evaluation on General Purpose Graphics Processing Unit (GPGPU). Firstly, the evaluation algorithm is implemented and tested on an in-house developed LCI, which is based on Michelson configurations. Furthermore, we focus on the performance optimization of the GPU-based program using the different approaches to further achieve efficient and accurate massive parallel computing. Finally, the performance comparison for evaluating measurement data using different approaches is discussed in this paper.

Experimental investigation on correlation of corona‐induced vibration and audible noise from DC conductor

In this study, the corona-induced vibration and audible noise (AN) on stranded conductor from positive and negative corona discharges were measured and analysed. The experiments were conducted in a semi-anechoic chamber to reduce the inferences from environment. For the measurement of vibration, the conductor was kept in dry condition without water drops on the conductor, which is different from previous investigations and can reveal the contributions of corona-generated space charges on the corona-induced vibration. Besides, the measurement of vibration on the conductor was performed by using a laser vibrometer which was a non-contact measurement device for measuring the vibration velocity. Furthermore, waveforms of corona-induced vibration and AN were measured simultaneously to analyse the correlation between them. The time and frequency domains characteristics of the vibration velocity and AN from negative and positive corona discharge are carefully analysed and no correlated relationship in time and frequency domains can be found in the two corona effects. It can be concluded that disturbance of air molecules caused by the vibration of conductor does not contribute the corona-generated AN.

An investigation of highly accurate and precise robotic hole measurements using non-contact devices

Industrial robots arms are widely used in manufacturing industry because of their support for automation. However, in metrology, robots have had limited application due to their insufficient accuracy. Even using error compensation and calibration methods, robots are not effective for micrometre (μ m) level metrology. Non-contact measurement devices can potentially enable the use of robots for highly accurate metrology. However, the use of such devices on robots has not been investigated. The research work reported in this paper explores the use of different non-contact measurement devices on an industrial robot. The aim is to experimentally investigate the effects of robot movements on the accuracy and precision of measurements. The focus has been on assessing the ability to accurately measure various geometric and surface parameters of holes despite the inherent inaccuracies of industrial robot. This involves the measurement of diameter, roundness and surface roughness. The study also includes scanning of holes for measuring internal features such as start and end point of a taper. Two different non-contact measurement devices based on different technologies are investigated. Furthermore, effects of eccentricity, vibrations and thermal variations are also assessed. The research contributes towards the use of robots for highly accurate and precise robotic metrology.

Efficient measurement of aero-engine blade considering uncertainties in adaptive machining

Blade geometry plays an extremely important role in the aerodynamic performance of aero-engine. However, in the adaptive machining process of a near-net-shape blade, it is important for an application engineer to reconstruct an actual profile with high-precision measurement data in a short time. This paper presents an efficient measurement to meet the requirement for digital information in the adaptive machining, which is also intimately associated with the previous work in reconstruction (Zhang et al. in Int J Adv Manuf Technol 2015:1–16, 2015). Comparing with conventional measurement, the proposed method can not only improve the utilization of measurement data from multi-sensor system but also consider the uncertainties of measurement and localization in data merging. Concretely speaking, the low-precision data from non-contact measurement device is used for establishing possible substitute models. The modified Bayesian information (Modi_BIC) criterion based on Bayesian statistics is introduced as the principle to select the model structure. In order to reduce misalignment errors of the selected substitute model, the statistical analysis of Fisher information matrix is applied to determine registration points. Based on this, the uncertainties can be given in the form of variation boundaries. Comparisons with the specified tolerance band determine a set of re-measured points by using a contact measurement device. The high-precision data can be merged with the selected substitute model by means of free form deformation (FFD) technique. The final measurement data is provided in the form of skinning surface that is consistent to the reverse modeling methodology of aero-engine blade. Moreover, some practical examples are given to demonstrate the effectiveness and superiority of the proposed method.

Size Effects on Mechanical Properties of Copper Thin Sheet in Uniaxial Tensile Tests

Microforming offers a reliable method for mass production of micro parts with low cost and high precision. However, to form micro parts is more difficult than macro parts because of size effects. Uniaxial tensile tests are carried out to study the size effects on mechanical properties of copper C1100 thin sheet at room temperature on a universal testing machine. The materials are thermally treated at 873 K for 12 h in nitrogen atmosphere, and the specimens with thickness varying from 0.32 mm to 0.04 mm are manufactured by slow feeding wire cutting with initial gauge widths of 8, 4, 2, and 1 mm. In addition, a non-contact measurement device is developed to reduce the error of the contact measurement method. The results show that the size effects on mechanical property are obvious. The flow stress and elongation decrease dramatically with the decreasing specimen size. The reason for this phenomenon is also discussed by scanning electron microscope (SEM) observation and theoretical analysis. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.5958

Non-Contact Measurement Device Based on Ultrasonic Technology

In the light of application requirements for non-contact measurement, this paper puts forward a non-contact measuring device. It generates the ultrasonic through electrical way with SCM detecting echo, the timer detecting ultrasonic transmitting and receiving time difference. Then it carries out the non-contact measurement of distance, and displays on LCD. The device can be used in many aspects, such as alarm, data monitoring, etc

An accurate loading experimental measurement device for superplastic free bulging

Superplastic alloy has very strong structure sensitivity. Superplastic bulging with a die of the plate is related not only to stress state but also closely to loading paths. It is an important basis for bulging forming with a die to study deformation law and experimental apparatus for superplastic free bulging, because the boundary of test piece is fixed and friction is insignificant for free bulging. In the paper, a pure high-pressure argon gas source is used as the loading media after it is heated by the heating system outside the furnace, which improves the heating efficiency and temperature uniformity of the test piece. The photoelectric non-contact measurement device can avoid negative influence on the additional stress and uneven temperature at the peak of bulging part caused by push rod in the contact measurement. The temperature and pressure of the test piece in cylindrical insulation furnace with blank holder give feedback control to improve the control precision. In loading gas channels, the pressure is adjusted by accurately measuring and controlling the rotation angle of the stepping motor, and is loaded by an electromagnetic valve. It significantly increases the response characteristics of the control pressure. This paper also introduces steps and methods to realize several typical loading paths, such as constant pressure, jump pressure and additional back & differential pressure loading. These provide a new way to measure the strain rate sensitivity index m value and improve the deformation speed of superplastic free bulging.

Measuring external profiles of porous objects using CMM

Coordinate measuring machine (CMM) has been extensively used in surface measurement and inspection. CMM produces more accurate and reliable results compared with non-contact measurement devices, since CMM measures target surfaces in a tactile way and is not affected by surface reflection quality. However, when there is porosity on the outside surfaces, CMM measurement will have errors because part of the probing stylus will come into the porosity spaces. This paper presents a method of using CMM to measure external profiles of objects with external porosity spaces. The center of a CMM probing stylus will be compensated to avoid porosity spaces and located above external surface areas along surface normal directions. Such a probing strategy can be implemented in both computer-aided design (CAD)-guided mode and non-CAD-guided mode. When the CAD model is available, the probing styli are guided to approach the surface along its normal directions successively to identify and avoid porosity spaces. When the CAD model is unavailable, surface normal directions will be estimated first and then adjusted. The presented method is able to avoid porosity spaces in CMM measurement regardless of the availability of CAD models.

Evaluation of a CCD-based facial measurement system

This paper describes the configuration and evaluation of a CCD-based biostereometric system at the Department of Orthodontics, Kings College Dental Hospital, London. The system has been designed to allow rapid and accurate measurement of facial soft-tissue shape with a minimum of traditional photogrammetric training. This has been achieved by automatic camera calibration and stereo matching, performed on a Sun Microsystem 3/160 workstation. In summary, the characteristics of the system are: (a) non-contract three-dimensional (3D) measurement of soft-tissue; (b) de-skilled, requiring little or no photogrammetric training; (c) rapid data acquisition, combined with slower off-line processing; (d) processing of resulting 3D surface information to yield cross-sections; (e) surface measurement accurate to within 0.5 mm. Accuracy assessment was performed using a manual electromechanical non-contact measurement device with precision exceeding the requirement of the biostereometric system.