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Unknown Surface Modeling Method Based on High-precision CMM
Yue Ping Chen,
Yi Chang Lu
Issue:
Volume 9, Issue 1, February 2021
Pages:
1-5
Received:
30 December 2020
Accepted:
12 January 2021
Published:
22 January 2021
Abstract: Reverse engineering is typically applied to solve the CAD model of unknown parts. As modern industry requirements on the accuracy of complex surfaces increase, setting up the high-precision CAD modeling of unknown complex surface parts through reverse engineering becomes an interesting research topic. Here, we present a method that combines manual measurement and automatic measurement with a high-precision coordinate measuring machine (CMM) to measure unknown complex-surface to obtain CAD model. In this study, the unknown complex-surface was fixed on the CMM worktable, and cancelling the probe compensation function of PC-DMIS before measurement. Then, 490 measuring points were obtained by manually moving the probe with a diameter of 5mm to measure surface. The measured points generated the CAD model, the CAD model was offset a probe radius, and determined the rough contours of the surface. This CAD model was automatically measured in a CMM, and the function of the “automatic measurement model” was iterated to obtain a high-accuracy CAD model. Each measurement was arranged with 20×20 measuring points. The accuracy of the CAD model obtained by each iterative measurement would be improved, and finally a high-precision CAD model was obtained. After 7 iterations, the final accuracy of the unknown surface CAD model was as high as 0.004 mm as compared to that of the actual part.
Abstract: Reverse engineering is typically applied to solve the CAD model of unknown parts. As modern industry requirements on the accuracy of complex surfaces increase, setting up the high-precision CAD modeling of unknown complex surface parts through reverse engineering becomes an interesting research topic. Here, we present a method that combines manual ...
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Application and Analysis of Random Forest Algorithm for Estimating Lawn Grass Lengths in Robotic Lawn Mower
Kazuki Zushida,
Zhang Haohao,
Hideaki Shimamura,
Kazuhiro Motegi,
Yoichi Shiraishi
Issue:
Volume 9, Issue 1, February 2021
Pages:
6-14
Received:
14 January 2021
Accepted:
21 January 2021
Published:
23 February 2021
Abstract: This paper states an estimation method for lawn grass lengths or ground conditions based on random forest algorithm from the observation data obtained by fusion of sensors. This estimation relates to Digital Twin and Virtual Twin of Hybrid Twin approach for the autonomous driving of robotic lawn mowers. The robotic lawn mowers are becoming popular with the advent of efficient sensors and embedded systems and we are now developing a practical autonomous driving and its group control algorithm for large lawn grass areas. However, one of the important functions of robotic lawn mower, that is, the length of lawn grasses or such ground conditions as dirt, gravel, or concrete, etc., are not recognized precisely with the current robotic lawn mower. As a result, the motor for cutting lawn grasses is running with constant rotation speed from the beginning to the end of operation of robotic lawn mower. This leads to the waste of battery and gives a large drawback for the control of robotic lawn mower. In order to precisely control the rotation speed of motor and save the battery, the lawn grass lengths and ground conditions are estimated by using the effective sensor data. The application of random forest algorithm to the fusion of sensors on a commercial robotic lawn mower attained more than 90% correct estimation ratio in several experiments on actual lawn grass areas. Now, the suggested algorithm and the fusion of sensors are evaluated against wide range of lawn and grounds.
Abstract: This paper states an estimation method for lawn grass lengths or ground conditions based on random forest algorithm from the observation data obtained by fusion of sensors. This estimation relates to Digital Twin and Virtual Twin of Hybrid Twin approach for the autonomous driving of robotic lawn mowers. The robotic lawn mowers are becoming popular ...
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Thermal Performance of MED-TVC Pilot at 95°C Elevated Temperature with Acid-anti-scalant Blend Treatment
Osman Hamed,
Amr Mohamed Mahmoud,
Khalid Bamardouf,
Ahmad Al Ghamdi,
Ali Al-Hamzah
Issue:
Volume 9, Issue 1, February 2021
Pages:
15-18
Received:
1 February 2021
Accepted:
9 February 2021
Published:
23 February 2021
Abstract: Enhancing the efficiency of desalination plants and economics of desalinated water are the major goal to researchers. In desalination industry; Multi Effect Desalination (MED) has an economic potential which proves its maturity among different desalination technologies. Large MED plants were built and operated with satisfactory performance in the last decade. They have been operated at low temperature compared to MSF and competitive operation efficiency. The Desalination Technology Research Institute (DTRI) which belongs to the Saline Water Conversion Corporation (SWCC) of Saudi Arabia has tested MED pilot plant with hybrid acid and anti-scalant treatment to control the scale. The test was conducted under 95 °C compared to 65 TBT which the current commercial standard operational temperature and previously tested 85 TBT within DTRI-SWCC pilot plant. Increase in the TBT would allow to increase the number of effects which lead to more system efficiency (the performance ratio) and then reduce fuel consumption which reflected in water unit cost of the desalinated water. The results showed that the thermal performance including fouling factor and performance ratio was constant and have very minor degradation during the test. The good thermal performance was confirmed by the post-operation visual inspection, which revealed that the heat transfer tubes were maintained in a clean condition after testing.
Abstract: Enhancing the efficiency of desalination plants and economics of desalinated water are the major goal to researchers. In desalination industry; Multi Effect Desalination (MED) has an economic potential which proves its maturity among different desalination technologies. Large MED plants were built and operated with satisfactory performance in the l...
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A Test Method for Helicopter Landing Gear Load
Issue:
Volume 9, Issue 1, February 2021
Pages:
19-24
Received:
18 January 2021
Published:
4 March 2021
Abstract: In this paper, a load test method of landing gear during take-off and landing of helicopter was proposed and the structure of helicopter landing gear, the modification of strain gauge bridge, the establishment of load calibration equation and the flight test of helicopter were studied. Firstly, according to the structure of helicopter landing gear, the stress analysis of landing gear was carried out, and the load position and force form of landing gear were determined during take-off and landing. Then, the measuring principle of the strain bridge was studied. According to the technical requirements, structural characteristics of the landing gear load test and the properties and principles of the strain bridge, the distribution and load measurement form of the strain bridge of the dangerous structure of the landing gear were designed. Then, studying load calibration test scheme of landing gear and carrying out load calibration test, the load calibration equation of landing gear was obtained, and the accuracy of load calibration equation was verified by comparing the expected load and actual load. Through the flight test, the landing gear load during the take-off and landing of the helicopter was obtained. Finally, the valid analysis of flight load data was carried out. The results show that the proposed method is feasible, and the flight test data of landing gear load are accurate and reliable, which can provide data support for the structure modification, fatigue analysis and the life evaluation of landing gear.
Abstract: In this paper, a load test method of landing gear during take-off and landing of helicopter was proposed and the structure of helicopter landing gear, the modification of strain gauge bridge, the establishment of load calibration equation and the flight test of helicopter were studied. Firstly, according to the structure of helicopter landing gear,...
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Kugel Ball as an Interesting Application of Designing the Hydrosphere
Ahmad Waguih Yacout Elescandarany
Issue:
Volume 9, Issue 1, February 2021
Pages:
25-32
Received:
3 February 2021
Accepted:
14 February 2021
Published:
10 March 2021
Abstract: Analytical solutions are not available for the partial hemispherical hydrosphere which called as the Kugel ball fountain or the Kugel ball. However, this study offers a comprehensive idea about this phenomenon presenting a design map that gives a panoramic sight enabling the designers to easily choose whatever specifications needed for their fountain. Through simplifying the author previous formulae for this type of bearings, this paper removes the mystery of the Kugel ball phenomenon and shows that no complicated mathematic or physics are needed, as believed, to be grasped for producing such fountains. A new simple design technique is used and the most two famous fountains (at the House of Science in Patras, Greece and the largest at the Science Museum of Virginia, Richmond, USA.) are checked as an application of this design. One of the most important side results of this study is finding the equilibrium point, discovered in the author previous papers, which was considered as the equilibrium point between the forces of centripetal inertia, viscosity and friction due to the surface roughness. It becomes clear that this point is a natural characteristic of this type of bearings.
Abstract: Analytical solutions are not available for the partial hemispherical hydrosphere which called as the Kugel ball fountain or the Kugel ball. However, this study offers a comprehensive idea about this phenomenon presenting a design map that gives a panoramic sight enabling the designers to easily choose whatever specifications needed for their founta...
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