Reverse Design and Test of Non-circular Gear & Crank-Rocker & Gear Trains Weft Insertion Mechanism

For the purpose of obtaining satisfactory performance of the non-circular gear & crank-rocker & gear trains (NCCRG) weft insertion mechanism which was proposed in this paper, the ideal kinematic curve of this weft insertion mechanism was given, and the reverse solution models of this mechanism were established. A reverse design and simulation software was compiled based on Visual Basic 6.0 to obtain the mechanism parameters, including the pitch curves and tooth profiles of the non-circular gears. A test-bed of this mechanism was developed according to these parameters. The kinematic performance of this weft insertion mechanism was tested by high-speed video tape recorder with its corresponding video analytical software Blaster's MAS. And the test results were identical with the theoretical calculation. Compared with the conjugate cam weft insertion mechanism which is applied on TT96 rapier loom, under the condition of same weft insertion rate, the variation of acceleration of this mechanism is smaller. This novel weft insertion mechanism can meet the requirements of weft insertion on rapier looms with smooth and steady motion.

Reverse design and tests of vegetable plug seedling pick-up mechanism of planetary gear train with non-circular gears

In the previous research,the seedling pick-up mechanism of the planetary gear train with incomplete eccentric circular gear and non-circular gears for vegetable plug seedlings still has two shortcomings.One is that not enough seedling pick-up depth leads to a low success ratio of seedling pick-up at high rotation speeds,the other is that the smaller seedling pushing angle results in poor seedling pushing effect.Therefore,the reverse design of the seedling pick-up mechanism based on its motion trajectory was carried out.The local trajectory of seedling pick-up and seedling pushing sections was adjusted to obtain the theoretical motion trajectory of the seedling pick-up mechanism.The cubic non-uniform B-spline curve was used to fit the adjusted trajectory.A novel seedling pick-up mechanism of the planetary gear train with non-circular gears was proposed,including three combined non-circular gears,four non-circular gears,one planetary carrier,and two seedling pick-up arms.The reverse design model of the mechanism was established.The analysis and design software of the mechanism was developed to obtain the mechanism parameters meeting design requirements.The virtual prototype of the mechanism was established and its physical prototype was manufactured.Through the virtual motion simulation and high-speed photographic kinematics bench tests of the mechanism,the kinematic model and results of reverse design of the mechanism were verified,with the kinematic performances of the mechanism prototype studied.The seedling pick-up tests of the mechanism were conducted in the laboratory.The success ratios of seedling pick-up were 94.2%,95.6% and 90.2% while the seedling pick-up efficiencies of the mechanism were 60,80 and 100 plants per minute per row,respectively.Besides,the seedling pushing effect was improved mush because of the greater seedling pushing angle.The seedling pick-up mechanism through revise design is of high value to be applied in the practical vegetable plug seedling transplanters.

A Reverse-Design Strategy for the Track Error of the Qi Tai Telescope Based on Pointing Accuracy

The Qi Tai Telescope(QTT),which has a 110 m aperture,is planned to be the largest scale steerable tele-scope in the world.Ideally,the telescope’s repeated pointing accuracy error should be less than 2.5 arc seconds(arcsec);thus,the telescope structure must satisfy ultra-high precision requirements.In this pur-suit,the present research envisages a reverse-design method for the track surface to reduce the difficulty of the telescope’s design and manufacture.First,the distribution characteristics of the test data for the track error were verified using the skewness coefficient and kurtosis coefficient methods.According to the distribution characteristics,the azimuth track error was simulated by a two-scale model.The error of the long period and short amplitude was characterized as large-scale and described by a trigonometric function,while the short period and high amplitude error was characterized as small-scale and simulated by a fractal function.Based on the two-scale model,effect of the error on the pointing accuracy was deduced.Subsequently,the relationship between the root mean square(RMS)of the track error and the RMS of the pointing accuracy error of the telescope was deduced.Finally,the allowable RMS value of the track error was derived from the allowable pointing accuracy errors.To validate the effectiveness of the new design method,two typical radio telescopes(the Green Bank Telescope(GBT)and the Large Millimeter Telescope(LMT))were selected as experimental examples.Through comparison,the theoretical calculated values of the pointing accuracy of the telescope were consistent with the measured values,with a maximum error of less than 10%.

Polyphenol-based hydrogels: Pyramid evolution from crosslinked structures to biomedical applications and the reverse design

As a kind of nature-derived bioactive materials, polyphenol-based hydrogels possess many unique and outstanding properties such as adhesion, toughness, and self-healing due to their specific crosslinking structures, which have been widely used in biomedical fields including wound healing, antitumor, treatment of motor system injury, digestive system disease, oculopathy, and bioelectronics. In this review, starting with the classi-fication of common polyphenol-based hydrogels, the pyramid evolution process of polyphenol-based hydrogels from crosslinking structures to derived properties and then to biomedical applications is elaborated, as well as the efficient reverse design considerations of polyphenol-based hydrogel systems are proposed. Finally, the existing problems and development prospects of these hydrogel materials are discussed. It is hoped that the unique perspective of the review can promote further innovation and breakthroughs of polyphenol-based hydrogels in the future.

Reversing design methodology of investment casting die profile based on ProCAST

Turbine blade is one of the critical components of aircraft engine.The performance of the engine depends on the shape and dimensions of components,but superalloy blade material cannot be easily machined.Although investment casting is an ideal process for such net-shape components,it requires an accurate determination of the casting-die profile.In this paper,a reversing design methodology for investment casting die using ProCAST is proposed.By combining the methods of simplifying grid files and quick sorting,the efficiency of sorting and matching can be largely improved.Further,the mould/die cavity anti-deformation system can be easily built.With ProCAST,the optimized die profile for investment casting can be established.

REVERSE MODELING FOR CONIC BLENDING FEATURE

A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.

COMPLEX SURFACE RECONSTRUCTION BASED ON OBJECT-ORIENTED DEVELOPING TOOL VBA

Taking AutoCAD2000 as platform, an algorithm for the reconstruction ofsurface from scattered data points based on VBA is presented. With this core technology customerscan be free from traditional AutoCAD as an electronic board and begin to create actual presentationof real-world objects. VBA is not only a very powerful tool of development, but with very simplesyntax. Associating with those solids, objects and commands of AutoCAD 2000, VBA notably simplifiesprevious complex algorithms, graphical presentations and processing, etc. Meanwhile, it can avoidappearance of complex data structure and data format in reverse design with other modeling software.Applying VBA to reverse engineering can greatly improve modeling efficiency and facilitate surfacereconstruction.

Process-based deep learning model:3D prediction method for shot peen forming of an aircraft panel

Shot peen-forming is a more precise method of forming aircraft panels than conventional methods.The traditional method of acquiring the process parameters relies mainly on prior theoretical knowledge and trial-and-error.Despite the finite element method’s ability to replace some experimentation,it still cannot realize the design of shot peen forming processes parameters of an aircraft panel based on a known contour.This study uses an innovative model-based deep learning approach to predict aircraft panel deformation and active design the shot peening parameters.The prediction time is less than 1 second,resulting in a significant reduction in computational time.The shot peen forming process parameters and the geometric structure characteristics of the aircraft panel are divided into independent channels to establish a high-dimensional feature map,which are used to train the deep learning model.The forming contours of the 2024-T351 high-strength aluminum alloy panel are predicted under different shot peening processes.In addition,the process parameters are designed according to the known contour of the forming process.To verify the precision of the proposed method,the designed shot peen forming process is used to manufacture a single curvature aircraft panel with a curvature radius of 3500 mm.There is good agreement between the forming contour and the theoretical design contour.The maximum deformation error is less than 1 mm and its mean error is 7.8%.The mean curvature radius error is 5.668%.The proposed method provides a new and practical reference to the precise design of the shot peen-forming process.

Development and experiment of the mechanism for oolong tea stirring motion based on the manual stirring characteristics analysis

In this study,the motion characteristics of manual stirring were analyzed to achieve the goal of realizing a highquality mechanized imitation of manual stirring for oolong tea.A test bench for collecting the motion characteristics of manual stirring was designed,and the standard manual stirring motion characteristic curve was obtained.According to the requirements of the stirring motion characteristics,a variable-speed and variable-amplitude stirring mechanism was proposed,the kinematics model and reverse design model of the stirring mechanism were established,auxiliary analysis and design software were written,and the non-circular gear pitch curve and cam profile curve were obtained.A three-dimensional model of the stirring machine was established,a virtual prototype of the stirring machine was built,and the simulation experiment was completed by using the ADAMS software.A prototype of the stirring machine was developed,and the stirring experiment was conducted on the prototype.The maximum deviation of the pitch angle is 2.8772°,and the maximum deviation of the roll angle is 1.5948°according to the analysis and comparison of the actual curve data and the theoretical data curve.The experimental results showed that the simulation angle curve and the actual angle curve were consistent with the theoretical standard manual stirring motion characteristic curve,which verified the correctness of the design and modeling of the stirring mechanism.The tea was mechanically stirred by the stirring mechanism to achieve the desired stirring effect,which verified the feasibility of the stirring machine.