CN-121977682-A - Paddy field grader vibration mode test verification and structure optimization method based on vision measurement and sensitivity analysis

CN121977682ACN 121977682 ACN121977682 ACN 121977682ACN-121977682-A

Abstract

The invention relates to a paddy field grader vibration mode test verification and structure optimization method based on vision measurement and sensitivity analysis, which comprises the steps of attaching mark points to key parts and establishing a coordinate system; shooting and analyzing videos by using a high-speed camera to obtain real-machine modal data, establishing a parameterized model, carrying out modal analysis and comparison verification with measured data, carrying out transient and harmonic response analysis to obtain three-dimensional amplitudes, carrying out sensitivity analysis and response surface optimization by taking key parameters and the amplitudes as optimization targets, obtaining optimal design parameters, and comparing to obtain an optimization result. The invention can provide an accurate mechanical structure optimization method based on a real mechanical structure, and belongs to the technical field of agricultural mechanical structure optimization design.

Inventors

ZHAO ZUOXI
ZHANG HAOJIA
ZHANG KANGRUI
ZOU WENQI
Hou Yingju
XU YUANJUN

Assignees

华南农业大学

Dates

Publication Date: 20260505
Application Date: 20260128

Claims (10)

1. A paddy field grader vibration mode test verification and structure optimization method based on vision measurement and sensitivity analysis is characterized by comprising the following steps: S01, measuring the specific size and length of each part of the mechanical structure of the existing initial paddy field grader, and attaching a BMW mark to the key part of the existing mechanical equipment to record the movement change of the key position when shooting; S02, placing a checkerboard plate under mechanical equipment in a pasting manner, and establishing a complete global space coordinate system; S03, shooting a video of the paddy field grader which works when the paddy field grader is subjected to external force by using a high-speed camera, guiding the excited video into TEMA software, analyzing and extracting amplitude curves of key parts of the paddy field grader in three spatial directions under a spatial coordinate system, then transmitting the data into MATLAB software for FFT conversion to obtain modal data of the paddy field grader, obtaining natural frequencies and corresponding damping ratios of the first two steps of the machine, comparing with the following simulation, and verifying the effectiveness of the simulation; s04, modeling a main mechanical structure of the existing paddy field grader under SOLIWORKS, and parametrically designing the size of a mechanical movable part; s05, importing the parameterized mechanical model into ANSYS for modal analysis, extracting the total deformation and the first sixth-order natural frequency of the mechanical structure of the paddy field grader at the current initial position, and modifying the model by using the first two-order natural frequency of the parameter as an output parameter and comparing the data obtained by the high-speed camera; S06, performing transient analysis in ANSYS, transmitting a harmonic response module, inserting the tension of a tractor suspension structure in a paddy field grader structure, the gravity of the grader and the soil load force, solving to obtain X, Y, Z three-direction amplitude of the paddy field grader under a space coordinate system after being excited, and selecting and outputting to a parameter set; S07, setting a result of finishing initial conditions by a simulation flow in ANSYS, outputting parameters into a parameter set, taking the parameter with higher sensitivity as an input parameter, wherein the output parameter is the amplitude of a first two-stage mode of the grader and a X, Y, Z-axis of the grader after being excited; S08, performing sensitivity analysis on the parameterized data set, and selecting parameters with higher sensitivity; s09, dragging the response surface optimization into a parameter set, clicking an experimental design, taking the first four-bit parameter with the highest sensitivity after parameterization screening as an input parameter, and constructing a response surface model by a result obtained by Latin hypercube design test, wherein the response surface type is selected by a genetic aggregation algorithm; and S10, performing experimental design and processing on the parameter set, constructing a response surface model, performing optimization solution to obtain an optimal design parameter, and comparing an optimization result corresponding to the optimal design parameter with the initial modal data in the step S05 to obtain a structure optimization result.
2. The paddy field grader vibration pattern test verification and structure optimization method based on vision measurement and sensitivity analysis according to claim 1, wherein in step S02, a global space coordinate system is established by defining a checkerboard plate as an XOZ plane of the global coordinate system, defining three mark points on the checkerboard plate, setting a first mark point as an origin of the global coordinate system in TEMA software, defining a direction connecting the first mark point and a second mark point as an X axis of the global coordinate system, defining a direction connecting the first mark point and a third mark point as a Z axis of the global coordinate system, and automatically generating a Y axis passing through the origin and being perpendicular to the XOZ plane by TEMA software, thereby establishing the global space coordinate system.
3. The paddy field grader vibration pattern test verification and structure optimization method based on vision measurement and sensitivity analysis according to claim 1, wherein in step S03, a Phantom VEO 410 high-speed camera is used for recording video, a light supplementing lamp is needed for supplementing light, and the key part is a part for pasting a BMW mark.
4. The paddy field grader vibration pattern test verification and structure optimization method based on vision measurement and sensitivity analysis is characterized in that in step S03, a preset code is used in MATLAB, pose transformation in data is converted into a vector, frequency and normalized data are converted and derived through a Fourier transformation matrix, and the effectiveness of the data in the code is processed by taking MAC confidence as a standard output parameter to obtain the mode data shot by a high-speed camera.
5. The method for testing, verifying and optimizing the structure of the vibration mode of the paddy field grader based on vision measurement and sensitivity analysis as set forth in claim 1, wherein the step S05 comprises: S051, a new mode analysis module is established, and material attribute assignment is carried out on the mechanical model; S052, carrying out grid division on the mechanical model, and adding corresponding contact, spring and/or connection pair constraint to the connection part; s053, solving the mechanical model by adopting a Lanczos mode extraction method to obtain the first six-order natural frequency and the corresponding vibration mode, and extracting the first two-order natural frequency; s054, fitting the modal data obtained by the high-speed camera with the modal data obtained by simulation, and judging whether the establishment of the mechanical model is reasonable.
6. The paddy field grader vibration pattern test verification and structure optimization method based on vision measurement and sensitivity analysis according to claim 5, wherein in step S052, tetrahedral units are used for meshing the simplified model of the paddy field grader.
7. The paddy field grader vibration pattern test verification and structure optimization method based on vision measurement and sensitivity analysis according to claim 1, wherein step S06 is: The method comprises the steps of transferring a new transient module to an original modal module, adding standard earth gravity, adding a fixed support on a mechanical structure, selecting all end faces connected to a tractor part by the fixed support, setting the time step to be 0.1 seconds, adding data of an acquired land impact load step, selecting a land leveling shovel of a mechanical model by a load applying end face, and solving to obtain the maximum equivalent stress maximum value as an output parameter; The method comprises the steps of transmitting a harmonic response module to a modal module, setting the minimum value of a frequency interval range to be 0Hz, setting the maximum value of the frequency interval range to be 20Hz in analysis setting, setting the solution interval to be 100, inserting the tension of a tractor hanging structure in a paddy field grader structure, the self gravity of the grader and the soil load force, solving to obtain X, Y, Z three-direction amplitude, and selecting and outputting the amplitude to a parameter set.
8. The paddy field grader vibration pattern test verification and structure optimization method based on visual measurement and sensitivity analysis according to claim 1 is characterized in that in S08, four parameters with higher sensitivity are beam length, liang Hou, rod length and rod width.
9. The paddy field grader vibration pattern test verification and structure optimization method based on visual measurement and sensitivity analysis according to claim 1, wherein in S08, correlation type selection uses spearman correlation, correlation average value precision selection is 0.1, and standard deviation precision selection is 0.02.
10. The paddy field grader vibration pattern test verification and structure optimization method based on vision measurement and sensitivity analysis is characterized in that in the step S10, an experimental design method is used for processing a parameter set, specifically, a central composite design method is selected in experimental processing, the value range of each input parameter is set to 90-110% of the initial value of the central composite design method, so that an optimized parameter value is obtained, the optimized parameter value is substituted into a model, and the simulation result of the optimized parameter value is compared with the initial modal analysis result of the step S05, so that an optimized result is obtained.

Description

Paddy field grader vibration mode test verification and structure optimization method based on vision measurement and sensitivity analysis Technical Field The invention relates to an agricultural machinery structure optimization design technology, in particular to an optimization method for increasing vibration frequency and reducing vibration amplitude aiming at the existing paddy field land leveler structure by a high-speed camera extraction mode and a response surface method. Background The rice is a main ration crop in China and the world, and the stable high yield of the rice is important to the national grain safety. The flatness of paddy fields is a core factor affecting the growth, irrigation efficiency, fertilizer utilization rate and mechanized operation quality of paddy fields. Because of the mismatch between the dynamic complexity of the working condition and the traditional static design method, a method capable of precisely acquiring the real vibration mode of the paddy field under the excitation of the actual paddy field and a set of scientific structure optimization flow based on a reliable model and aiming at improving the dynamic performance are lacking. The main excitation sources born by the paddy field grader during operation are road surface and engine vibration. When the low-order natural frequency of the device structure is coupled with the excitation frequency, resonance is caused, and the performance reliability of the device is severely restricted. The resonance greatly reduces the operation stability and the leveling precision of the land leveling shovel, influences the crop growth environment, leads the fatigue damage of structural members to accelerate due to continuous alternating stress, shortens the service life of the whole machine, increases the maintenance cost, and simultaneously leads the driver to easily generate the problems of driving fatigue and the like due to vibration transmission. The prior art shows that the main excitation frequency of the paddy field surface to the running gear is concentrated in a low frequency range from 0.8Hz to 4.5Hz, and the typical excitation frequency of a matched engine is about 18Hz. In order to avoid harmful resonance and improve the working quality and the durability of equipment, one of the core design targets is to effectively avoid a main external excitation frequency band and shift to a higher frequency band by the low-order natural frequency (especially first-order and second-order frequency) of the paddy field grader system through structural optimization. However, the conventional design method based on statics lacks accurate prediction and effective regulation means for the overall dynamic characteristics, which results in difficulty in achieving the above-mentioned objects. Therefore, the invention provides an improved scheme for acquiring typical data such as modes and the like by combining a high-speed camera with the actual working condition of the paddy field grader, and simulating further optimization through ANSYS software. Disclosure of Invention Aiming at the technical problems in the prior art, the invention aims to provide a paddy field grader vibration mode test verification and structure optimization method based on visual measurement and sensitivity analysis, which can provide an accurate mechanical structure optimization method based on a real mechanical structure. In order to achieve the above purpose, the invention adopts the following technical scheme: A paddy field grader vibration mode test verification and structure optimization method based on vision measurement and sensitivity analysis comprises the following steps: S01, measuring the specific size and length of each part of the mechanical structure of the existing initial paddy field grader, and attaching a BMW mark to the key part of the existing mechanical equipment to record the movement change of the key position when shooting; S02, placing a checkerboard plate under mechanical equipment in a pasting manner, and establishing a complete global space coordinate system; S03, shooting a video of the paddy field grader which works when the paddy field grader is subjected to external force by using a high-speed camera, guiding the excited video into TEMA software, analyzing and extracting amplitude curves of key parts of the paddy field grader in three spatial directions under a spatial coordinate system, then transmitting the data into MATLAB software for FFT conversion to obtain modal data of the paddy field grader, obtaining natural frequencies and corresponding damping ratios of the first two steps of the machine, comparing with the following simulation, and verifying the effectiveness of the simulation; s04, modeling a main mechanical structure of the existing paddy field grader under SOLIWORKS, and parametrically designing the size of a mechanical movable part; s05, importing the parameterized mechanical model into ANSYS for modal analysis, extra