High-precision Work Research Articles

Scientific preparation for JRT: Wind pressure prediction model for large radio telescope based on real data from multi-sensors

Jingdong 120-meter radio telescope (JRT) is poised to become the world's largest single-aperture fully steerable medium-low frequency radio telescope. However, like other large-aperture radio telescopes, the JRT is vulnerable to wind loads, which can cause structural deformation and pointing errors. Addressing this challenge requires the ability to predict dynamic winds in real-time. This study developed a wind pressure preprocessing and prediction model using sensor data collected from the Kunming 40-meter radio telescope (KRT), enabling real-time prediction of wind pressure on the telescope. The model employs adaptive noise and Variational Mode Decomposition (VMD) techniques to eliminate random noise from the original wind pressure data. Subsequently, wind pressure predictions are made using a Bidirectional Long Short-term Memory (BiLSTM) model. By conducting predictions under various stabilization conditions and conducting a thorough analysis of measurement data from five sensors, the study has achieved impressive results in predicting wind pressure on the KRT reflector surface. The proposed model demonstrates the lowest MAE, RMSE, and MAPE, while achieving the highest R2 across various data sets. Where the average R2 of the proposed model is 0.9392 at 45° pitch angle attitude and the RMSE, MAE and MAPE values are 1.4923, 1.2377 and 1.82% respectively. This model helps wind load monitoring of real-time wind pressure monitoring of the telescope surface, to study the effects of wind load on pointing accuracy. By adjusting the control parameters to reduce wind load interference, to ensure the high-precision work of a large radio telescope, such as JRT.

STUDY ON THE PREPARATION OF TECHNICAL DOCUMENTATION NECESSARY FOR THE REHABILITATION AND MODERNIZATION OF ROAD INFRASTRUCTURE IN THE AGRITOURISTIC AREA, GIUBEGA-BĂILEȘTI

The purpose of the study is to carry out a complex and high-precision work necessary for the realization of the first phase of the execution project, after which, based on all the drawn and written parts existing in the project, to carry out the field application of the construction works of the road, as well as control and reception works. The technical documentation produced had to meet all the technical standards of precision and quality imposed by the standards in force, that is why the most modern devices and existing work methods were used for the topographic surveys, which led to obtaining a high economic efficiency. The preparation of the location and delimitation plan of the studied road was made from the absolute coordinates of the support points and details, calculated on the basis of the elevations carried out on the ground, with the help of a high-performance program, which allowed the representation with great ease and accuracy, on a large scale 1: 500, of all the details existing on the land. Based on the completed technical documentation, the file was submitted to OCPI-Dolj, it was approved and entered in the Land Registry. Also, the execution project was carried out and the actual plotting on the ground of the road rehabilitation and modernization works, which will contribute substantially to increasing the safety and accessibility of all tourist reception structures.

REMOTE CONTROL SYSTEM OF STEPPER MOTOR BASED ON THE ESP32 DEVELOPER BOARD

The stepper motor is a unit of a control system to achieve the goal of convenient use and precise control, which greatly facilitates our life and improves the level of the modern high-tech industry. In particular, multiple stepper motors may be joined in a system and work together with a remote-control program, which greatly improves the flexibility and applicability of the equipment. In real life, multiple stepper motors are used together more often. For example, a 3D printer, using three stepping motors at the same time, the x-axis, the y-axis, and the z-axis, can determine the left side of the space and accurately print the 3D three-dimensional object we need. By adding a remote-control system, we can control the movement of the motor in real time and can replace humans to complete complex and high-precision work. For example, endoscopes are often used in medicine, when the endoscope needs to make micro adjustments in position, we can use remote control to make real-time adjustments. The project of using ESP32 to control multiple stepper motors and uses python language to write programs based on microPython firmware to realize remote control of multiple stepper motors is introduced. The speed and direction of the stepper motor can be adjusted and controlled by pulse signals. The clock system of ESP32 can generate pulse signal PWM, ESP32 comes with a WiFi module, which can support remote control. The speed of the stepper motor can be adjusted by adjusting the duty cycle of the PWM by the program. Combined with ESP32 products, the performance of this designed product can be stable and reliable. The clock system of ESP32 has multiple timers and with their use with the interrupt system, multiple stepper motors can be efficiently controlled simultaneously. And the WiFi module of ESP32 can realize remote control easily and conveniently. According to the principle of the stepping motor, the half-step control, and full-step control are realized. Additionally, a micro step mode with PWM signal with cosine function is designed to control the stepper motor. A user-friendly web application has been developed to control the system of four motors, allowing you to remotely control a four-engine system in a simple and convenient way

Dasymetry Dash Flood (DDF). A method for population mapping and flood exposure assessment in touristic cities

Population disaggregation methods are a land management tool that is necessary to robustly assess the exposure of populations to natural hazards. The aim of these methods is to translate population values from large spatial units to smaller spatial units. Due to their improvement, the accuracy in quantifying the population exposed to natural hazards has increased significantly in recent years. However, in the case of floods, where the actual exposure to the hazard depends on the height of the buildings, there is a methodological deficiency with regard to reaching the necessary level of detail. This is a methodological challenge that is exacerbated in urban areas specialising in tourism, where there are a large number of dwellings dedicated to the housing of tourists. In this paper we propose a 3D cartographic dasymetry (DDF) method that, based on cadastral information and the population and housing census, manages to solve these problems of flood hazard exposure assessment reasonably well. For validation, the results are compared with three widely used 2D methods. Our work shows that the proposed method offers better outputs for use in high-precision work; but also, when such detail is not necessary, more basic methods achieve results with only marginal differences.

Design and Analysis of Robotic Arm for Serving Material in Automotive Industry

The Robotic arm plays an important role in industries for performing tasks which are dangerous for humans, high precision work and carrying heavy load. This work is related to design and analysis of a robotic arm that might be used for pick and place operations for carrying heavy weight. Solidworks was used for model. ANSYS software was used to simulate the CAD models of structures, electronics, or machine components for analysing strength, elasticity, toughness, and temperature distribution. Importing a CAD model into the ANSYS software helps in examining a robotic arm under loading condition. After the completion of the design, the stress variation and deformation of the robotic arm by using different materials and under provided loading condition were obtained.

Singular Configuration Analysis and Singularity Avoidance with Application in an Intelligent Robotic Manipulator

Recently, robotic sensor systems have gained more attention annually in complex system sense strategies. The robotic sensors sense the information from itself and the environment, and fuse information for the use of perception, decision, planning, and control. As an important supplement to traditional industrial robots, co-bots (short for co-working robots) play an increasingly vital role in helping small and medium-sized enterprises realize intelligent manufacturing. They have high flexibility and safety so that they can assist humans to complete highly repetitive and high-precision work. In order to maintain robot safe operation in the increasing complex working environment and human–computer intelligent interactive control, this paper is concerned with the problem of applicant accuracy analysis and singularity avoidance for co-bots. Based on the dynamic model with load and torque sensors, which is used to detect the external force at the end of the robot, this paper systematically analyzes the causes of singularity phenomenon in the robot motion control. The inverse solution is obtained by analytical method and numerical method, respectively. In order to ensure the smooth and safe operation in the whole workspace, it is necessary for a robot to avoid singularity. Singularity avoidance schemes are utilized for different control tasks, including point-to-point control and continuous path control. Corresponding simulation experiments are designed to verify the effectiveness of different evasion schemes, in which the advantages and disadvantages are compared and analyzed.

2D LiDAR based object detection and tracking on a moving vehicle

Environment perception is an important capability for fully autonomous operation of agricultural machinery. High-precision work requires perception systems that are able to locate objects with high and specified accuracy. In this paper, we present an object detection and tracking system in a global coordinate frame based on 2D LiDAR data and RTK-GNSS positioning. The LiDARs and the RTK-GNSS device are installed on a tractor that is moving while the data is recorded. The final mapping result is compared to an RTK-GNSS based ground truth measurement of the object positions. For a test setup with four objects on a clover field, the average object positioning accuracy of the LiDAR system was determined to be 0.135 m (CEP50) and the worst case accuracy was 0.178m (CEP50). The preliminary results from this study can be used as a basis for determining requirements for safety margins when using this system for autonomous driving.

Synopsis of the Speed Control Methods of Electric Drives with BLDC Motor

The use of BLDC motor has had rapid growth in various applications, in all areas of use of electromechanical systems. This has come as a result of not only the advantages, that have the BLDC motor compared to other types of electric machines of alternating and direct current, but also the possibility of using all control methods to ensure safe and high-precision work, which have given it a very large advantage in adapting it to perform a variety of tasks. Electronic control of BLDC motor gives it the advantage of being suitable for control schemes, starting with the ones with sensors, to determine the position of the rotor, to sensorless methods, from traditional control methods PI, PID and up to advanced and intelligent control methods, or in the production of controllers as integrated circuits, for specific commercial purposes. This advantage makes possible for the motor to be selected for different functions, be flexible and adaptable. BLDC motor control can be accomplished with or without sensor methods. The advantage of sensorless control methods is the realization of the required quality indicators at the lowest cost. But the disadvantage of BLDC control methods without sensors is that it needs a control algorithm and more complex electronic circuits. The purpose of this paper is to examine the different methods of BLDC motor control with sensor and without sensor, to point out the advantages and disadvantages of each, as well as to recommend the field of application of each of these methods. Based on the literature review all of these control methods for electrical transmissions with BLDC motor, will be briefly reviewed in this paper.

Implementasi Pengendalian Robot Mobil Pencari Target Dan Penghindar Rintangan

Robots are useful to help humans in performing jobs that require high precision, substantial labor, repetitive and dirty work, and high-risk or dangerous jobs. Those are the high-risk human jobs that a robot can do. Wheeled robots have the ability to go to the targeted position. Proportional control is used to control the movement of robots. In addition, the robot will also be equipped with PI control method to adjust the actual wheel speed of the robot. The block diagram of the obstacle-driven avoider robot consists of push button, rotary encoder, ultrasonic sensor, Atmega, IC L298D, DC Motor and Light. The results of the obstacle-driven avoider robot, wheeled robots have the ability to run in accordance with the desired black line. Proportional control is used to control the movement of robots. In addition, the robot will also be equipped with ultrasonic sensors to set the robot in avoiding obstacles. Based on the results of testing and analysis that have done, it is suggested that there is tool that can be provided to develop a more sophisticated technology like adding sensors or more features.

Abstracts from the 131st Meeting of the Tennessee Academy of Science November 2021

Adam Holley grew up in Raleigh, North Carolina, but attended college in Pennsylvania, where he earned a B.S. in physics and mathematics from Haverford College. Uncertain about whether theoretical or experimental physics was right for him, he temporized by teaching high school physics in New York City, where he had the good fortune to collaborate on the development and teaching of a three-year research course for high school students. That experience ultimately helped him decide to become an experimentalist. This he did at North Carolina State University, joining a group of scientists developing the United States' first ultracold neutron (UCN) source at Los Alamos National Lab. He earned his Ph.D. as part of the associated UCNA experiment that for the first time used UCN to measure the neutron beta decay asymmetry. During his subsequent postdoc at Indiana University, Dr. Holley got involved in another beta decay experiment called UCNτ. He continued his involvement with that effort when he joined the faculty at Tennessee Tech, where he leverages unique aspects of UCN physics to involve undergraduates in the work. The Tortoise and the Hare: A Race for Answers to Big Questions about the Universe The production of energetic exotic particles has long been a primary method for discovering the rules that underlie what we observe about the universe. There are, however, a number of gaps in this understanding, which the study of more familiar systems, such as neutrons, atoms, or molecules, can help elucidate. As the overall precision of these experimental efforts increases, there are a growing number of tantalizing anomalies, any of which could point the way to a shift in our understanding of how the universe formed, what makes it up, and whether ours is the only universe or is one of many universes. The race to discover new fundamental physical behavior currently features a diverse array of high-precision approaches, spanning an enormous range of energies. “Ultracold” neutrons (UCN), with twenty orders of magnitude smaller energies than particles produced at the Large Hadron Collider, provide one example of how low-energy measurements can facilitate the requirement for high precision. A classic example of a UCN-based experiment is determination of the free neutron lifetime, an empirical observable involved in a number of potentially interesting anomalies. An experiment called UCNτ that operates at Los Alamos National Laboratory has set the standard for precise determinations of this quantity. Using UCNτ as an example of the physics, engineering, and computational challenges high-precision work entails, this talk will describe the ongoing race to answer some long-standing questions about the universe.

Ability of RTK-Based GPS Measurement Method in High Accuracy Work in Geomatics Study

Abstract: Insfrastructure development require significant changes and transformation in Geomatics field for the upcoming decade. The use of new technology in Geomatics and surveying is essential and can be leveraged in many survey application that will help on building the nation towards a sustainable future. In the last 5 years, GNSS technology has been widely used and practiced to replace total station for survey work. Main factors that contributes to this busniness changes are the availability of much cheaper equipment with good technical capability in the market that helps surveyor to perform their work faster and more efficient. Global navigation satellite system services for accurate positioning has also rapidly increased and provide many option and solution for industry player or surveyor to choose. Combination of multiple global navigation satellite system providers such as GPS, GALILEO,GLONASS and BeiDOU has developed good satellite networks and increased numbers of available satellites for observation that improve absolute position accuracy. CHC i70 is among the best selling GNSS model on the market right now. The receiver can receive signal from GPS,GALILEO,GLONASS and BeiDOU simultaneously. This study will outline and focus on the capability of the RTK-Based method ( 30 second to 1 minute observation period) using CHC i70 instrument in high-precision measurement work. The research was done using the GPS calibration test site at Politeknik Sultan Haji Ahmad Shah (POLISAS) and was also practiced in the actual work for establishment of Temporary Bench Mark (TBM) along Jalan Melor to Ketereh, Kelantan. The result of the study found that RTK-Based method can meet the precision work that is permitted under 2cm accuracy. Studies show that the method of using RTK- Based is suitable for high precision work and improve the measurement time and work duration at field.
 
 Keywords : Beidou, Chc and RTK-Based GPS and PDOP

ОПРЕДЕЛЕНИЕ ОПТИМАЛЬНЫХ ПАРАМЕТРОВ ДЛЯ ВЫЧИСЛЕНИЯ ПОПРАВОК ЗА РЕЛЬЕФ НА ОСНОВЕ ЦИФРОВЫХ МОДЕЛЕЙ РЕЛЬЕФА МЕСТНОСТИ (НА ПРИМЕРЕ ВОСТОЧНОГО ЗАБАЙКАЛЬЯ)

The study of corrections for the influence of terrain is a very popular and significant procedure in the production of high-precision gravimetric work. The results of such studies allow us to determine the optimal parameters for calculating terrain corrections, which helps to reduce the error in calculating the anomaly of the force of gravity in the Buge reduction and, accordingly, leads to an increase in the quality of the interpreted material. Therefore, the improvement of the methodology for calculating corrections for terrain is of particular interest for gravity exploration today and is a very relevant direction in high-precision surveying. Thus, in this article, the purpose of the study is to determine the optimal parameters for calculating terrain corrections for during high-precision gravimetric surveying. The degree of elaboration of the study indicates a number of unresolved issues, which are to some extent disclosed by the authors as a result of calculations and analysis of digital grids, graphs and other data involved in calculating terraincorrections. The article discusses the actual materials and methods for determining corrections for the influence of terrain, obtained during the production of high-precision field gravimetric work on one of the objects of the Trans-baikal Territory. In the course of the study, the results of determining the terraincorrections are presented, comparisons of the corrections in different zones are made, their quantitative indicators are analyzed, and statistics are provided. With the help of mathematical modeling, matrices (grids) of calculated parameters are constructed. The results of the study are clearly demonstrated in the diagrams and in the final tables, which indicates the reliability of the study performed. On the basis of the conducted research, conclusions are drawn and recommendations are made for the method of calculating corrections for the influence of terrain

Factors to be considered in establishing a scanning laboratory for testing the accuracy of terrestrial laser scanning technologies

Laser scanning is a 21st century mapping technique that is used to generate high density point cloud data in three dimensions (3D). The 3D scans can be used for surveying, mapping and monitoring of rock mass movement in mining. For high precision and reliable work, the instrument must be used correctly, regularly calibrated and checked to ensure that it constantly performs according to manufacturer's specifications. In this study, a Leica Total Station TCR 1201+ and a Trimble S6 Total Station were used to establish accurate coordinates for a control beacon and scanning targets. Thereafter, the scanning of the targets was carried out using a FARO Focus XD 130 terrestrial laser scanner. A comparison was conducted using the coordinates from the terrestrial laser scanner and total station to examine the point accuracy of the FARO scanner. The result from the comparison between the laser scanners coordinates and the total station coordinates showed that the FARO Focus is capable of producing accurate point cloud data that can be used for the purpose of monitoring underground rock mass movements. Lessons learnt during the development of the short-range scanning laboratory are summarised as factors to be considered when establishing such a laboratory. These include, operator knowledge, skill and work flow, robust target design, scanning geometry, full target visibility during scanning, calibration of instruments, laser scanner field of view and application of systematic error propagation during measurements.

Modeling and Analysis of Articulated Robotic Arm for Material Handling Applications

The Articulated Robotic Arm is gaining huge importance in industries due to its high precision work and ease in carrying out heavy tasks. This paper is related with the modeling and analysis of an articulated robotic arm which can be utilized for material handling tasks. For designing and simulation of the articulated robotic arm with material handling gripper SOLIDWORKS® software is used. In the process of modeling, an analysis such as the study of the finite element method would be very helpful in the early stage of design. The result of the analysis will show the strength and weakness of the design. The finite element analysis was carried out using ANSYS® software workbench to study the model of a robotic arm with different materials and various loading conditions. The results of the analysis are reviewed for selecting the best material and also approving good feasibility of the articulated robotic arm.

A Robust Blade Design Method based on Non-Intrusive Polynomial Chaos Considering Profile Error

To weaken the influence of profile error on compressor aerodynamic performance, especially on pressure ratio and efficiency, a robust design method considering profile error is built to improve the robustness of aerodynamic performance of the blade. The characteristics of profile error are random and small-scaled, which means that to evaluate the influence of profile error on blade aerodynamic performance is a time-intensive and high-precision work. For this reason, non-intrusive polynomial chaos (NIPC) and Kriging surrogate model are introduced in this robust design method to improve the efficiency of uncertainty quantification (UQ) and ensure the evaluate accuracy. The profile error satisfies the Gaussian distribution, and NIPC is carried out to do uncertainty quantification since it has advantages in prediction accuracy and efficiency to get statistical behavior of random profile error. In the integrand points of NIPC, several surrogate models are established based on Latin hypercube sampling (LHS) + Kriging, which further reduces the costs of optimization design by replacing calling computational fluid dynamic (CFD) repeatedly. The results show that this robust design method can significantly improve the performance robustness in shorter time (40 times faster) without losing accuracy, which is meaningful in engineering application to reduce manufacturing cost in the premise of ensuring the aerodynamic performance. Mechanism analysis of the robustness improvement samples carried out in current work can help find out the key parameter dominating the robustness under the disturbance of profile error, which is meaningful to further improvement of compressor robustness.

Gamma-ray branching ratios in the decay of 49Cr

The $\gamma$ -decay branching ratios of 49V have been studied in the $\beta$ /EC decay of 49Cr. The $\gamma$ -ray spectrum has been measured with a 70% relative efficiency co-axial germanium detector calibrated in efficiency with a precision of about 0.5%. The primary result is the measurement of the relative branching ratios of the three main $\gamma$ rays in the decay of 49Cr. Large discrepancies were found with a previous experimental work. The 49Cr sample was produced by proton impact on a ZrO2 target and collected at the ISOLDE facility of CERN and enabled us to re-evaluate the decay scheme of 49Cr. The new data allow the use of this nucleus for future high-precision calibration work.

Optimization of process parameters for surface roughness of Inconel 625 in Wire EDM by using Taguchi method

WEDM is the widely adopted non convectional machining process which is mainly used for machining very hard and tough material like super alloys. Application of WEDM is mostly found in aerospace, die making etc. industries due to high accuracy and precision work. Inconel is mainly a super alloy which is mixture of nickel and chromium, which is very high melting point and strength. Due to these properties Inconel is mainly machined by WEDM. In this paper attempt was made to optimize the different process parameters like pulse on time, pulse off time and peak current for the surface roughness. Taguchi L9 orthogonal array along with ANOVA is used for optimize the different parameters so that minimum surface roughness obtained. From the experiment results found that pulse on time is the most significant factor (contributing 92.35 %) and peak current is an insignificant factor. At the end, confirmation test have conducted to verify the results. Keyword: WEDM, Inconel 625, Taguchi method, ANOVA, Optimization

Overconfidence in photometric redshift estimation

We describe a new test of photometric redshift performance given a spectroscopic redshift sample. This test complements the traditional comparison of redshift {\it differences} by testing whether the probability density functions $p(z)$ have the correct {\it width}. We test two photometric redshift codes, BPZ and EAZY, on each of two data sets and find that BPZ is consistently overconfident (the $p(z)$ are too narrow) while EAZY produces approximately the correct level of confidence. We show that this is because EAZY models the uncertainty in its spectral energy distribution templates, and that post-hoc smoothing of the BPZ $p(z)$ provides a reasonable substitute for detailed modeling of template uncertainties. Either remedy still leaves a small surplus of galaxies with spectroscopic redshift very far from the peaks. Thus, better modeling of low-probability tails will be needed for high-precision work such as dark energy constraints with the Large Synoptic Survey Telescope and other large surveys.

Analysis of the Production of Ribbons of Copper-Phosphorus Solder by the Lateral Flow of a Melt onto a Rotating Roller Mold

Copper-phosphorus solders in the form of ribbons with a phosphorus content of 5–8%, thickness of 0.2–1 mm, and width of 10–20 mm are widely used to secure windings and contacts in electrical machinery. Certain alloys which are based on the copper–phosphorus system and contain a nickel addition are made in the form of ribbons that are in the amorphous state and are less than 100 μm thick. They are used to solder copper alloys in high-precision assembly work. Since the processing properties of copper-phosphorus solders are usually equivalent to those of solders that contain silver, they are used in place of silver-bearing solders as long as the finished joints have the required service characteristics. One serious drawback of copper-phosphorus solders is the difficulty in shaping them, which is due to the presence of brittle copper phosphide in the structure (this phosphide can account for up to 50% of the volume of the solder in some cases). Some factories fill their own needs for solder by turning heated cylindrical ingots on a lathe to make chip-shaped ribbons thinner than 1 mm. Such a technology is obviously unsuited for industrial use. Thus, in international practice copper-phosphorus alloys are made either by hot deformation or by casting a melt on a rotating mold. To more thoroughly investigate copper-phosphorus solders and the entire process of making them by feeding a melt laterally onto a rotating roller mold, tests were performed with the use of different speeds of rotation of the mold. The speed of the mold affects the geometric parameters and structure of ribbons based on alloy PMF7. The results of the tests are reported in this article.

A Quantitative Assessment of Low Back Pain in Dentistry

Previous research has shown that work related musculoskeletal disorders (WMSDs) caused by overexertion, awkward postures and repetitive motion are common among dental professionals. Literature suggests that the prevalence of general musculoskeletal discomfort ranges between 64 and 93 percent. Combined with a flexed cervical spine, dentists may experience the demands of high precision work and sustained static loading in the back, neck and shoulders. The primary means of assessing these disorders in dentistry has been through empirical studies using self-reporting and non-quantitative observational studies. This research provides a quantitative means of assessing mechanical/physical risk indicators of low back pain (LBP) in dentistry. A motion tracking system was employed to quantify posture variations of twelve professional dentists as four specific dental procedures (cavity preparation, tooth extraction, mirror check, and application and removal of a dental dam clamps) were performed using a patient simulator in a laboratory controlled environment. Four independent variables (IVs were general posture, precision, line of vision, and grip type. The dependent variables (DVs) were three lumbar spine intervertebral ranges of motion (ROM) - flexion, lateral flexion and axial rotation. Eight of 32 trials were analyzed. Four ranges of motion limits were assessed – the action limit (AL), maximal permissible limit (MPL), safe working range/zone (SWZ) limit, and risk of injury (ROI) limit. The focus is on the results of the seated/standing posture for the assessed four ROM limits. The MANOVA showed there were no significant 2, 3 or 4-way interactions and that only the precision variable was statistically significant (p < 0.05). When task were performed in seated and standing postures, lateral flexion and axial rotation ROM limits for risk of injury were consistently exceeded. Data were analyzed to present biomechanical evaluation of abnormal lumbar ranges of motion believed to be associated with increased risk of LBP, and provides insight into understanding causes and prevention of WMSDs particularly among dental professionals.