15 results about "Modal testing" patented technology

This invention belongs to the field of structural dynamics testing and modal analysis technology, and provides a physical / mathematical integrated experimental modal analysis method, system, equipment, and medium. The method includes: applying preliminary excitation and using the phase separation method to obtain preliminary modal parameters containing mode shapes; constructing a mode shape matrix based on the mode shapes and optimizing the position and number of exciters to ensure that the modal participation values ​​of all modes of interest are not lower than a preset threshold; performing refined excitation according to the optimized scheme, locking the resonance state using the phase resonance method, and obtaining the final modal parameters. This invention effectively solves the problems of blind excitation point placement, modal confusion, and mode omission by coordinating three stages: phase separation initial screening, mode shape-driven excitation optimization, and phase resonance fine measurement. It significantly improves the integrity, accuracy, and efficiency of modal testing of large structures and reduces experimental safety risks. It is applicable to ground vibration tests of complex structures such as aircraft, spacecraft, and bridges.

The present application belongs to the technical field of mechanical structure, and particularly relates to a method for reducing working vibration of a gear of a helicopter transmission system. The method uses a three-dimensional model of the gear or the gear ring and finite element calculation to obtain the first four modal frequencies. According to the gear structure, slots are formed at the gear web, the inner and outer diameters of the gear ring, or the gear weight-reducing holes before static or dynamic balancing of the gear. A damping ring or a damping block is installed at the slots, and then modal testing is performed. By adjusting the damping ring or the damping block, the working vibration is relatively reduced, and the processability and maintainability of the large gear are improved. The method can reduce harmful working vibration of the gear or the gear ring without changing the original structure, does not additionally increase the weight of the gear or the gear ring, and has repeatability. The method can be repeatedly improved according to the modal test results of each adjustment to achieve the best effect of reducing harmful working vibration.

The present application belongs to the technical field of milling processing, and discloses an incremental self-excitation method for identifying the low-frequency frequency response function of a milling robot. The method comprises the following steps: S1, in a preset standard posture, an incremental self-excitation experiment is performed by using a mass block, then a modal test is performed at a tool center point of the robot to obtain a frequency response function of the robot in the preset standard posture, and the frequency response function is used to solve an inertial self-excitation of the robot in the preset standard posture; S2, the robot again performs an incremental self-excitation experiment by using the mass block in a target posture in which the frequency response function needs to be identified, and the impulse and impulse moment of the mass block at the end of the robot during the experiment are calculated; S3, the frequency response function of the robot in the target posture is solved by using the impulse and impulse moment of the mass block and the inertial self-excitation of the robot in the preset standard posture. Through the present application, the identification of the frequency response function of the robot in any posture is solved.

The application relates to a penetration test method, device and computer equipment for a nursing robot. The method comprises the following steps: scanning firmware equipment and an operating system of a to-be-tested robot to obtain information test results of the to-be-tested robot; acquiring image information and voice information collected by the to-be-tested robot, respectively performing disturbance processing on the image information and the voice information to obtain disturbed image information and disturbed voice information, and obtaining multi-modal test results based on current execution results of the to-be-tested robot on the disturbed image information and the disturbed voice information; injecting a fake force feedback signal into a mechanical arm control system of the to-be-tested robot, and obtaining physical test results according to pressure detection results of the mechanical arm control system; and obtaining penetration test results of the to-be-tested robot according to the information test results, the multi-modal test results and the physical test results. The method can comprehensively test the nursing robot.

The application provides a correction system and method of a shock absorber simulation model and a road noise correction system. The correction system comprises a shock absorber simulation model, a modal test component and a modal analysis device. The modal analysis device is configured to obtain standardized first modal data and second modal data, perform matching analysis on the second modal data and the first modal data, and correct multiple simulation parameter values of the shock absorber simulation model until a matched shock absorber simulation model is determined when it is determined that the second modal data and the first modal data do not match. A two-stage progressive correction system framework of "test-parameter coupling correction" is proposed, which reduces the complexity of the system. A multi-dimensional parameter synchronous correction mechanism of the shock absorber simulation model is proposed, which integrates three types of parameter collaborative correction of damping nonlinearity, bushing frequency variable stiffness and main structure modal. Performance correction is performed through modal fitting, which improves the modeling accuracy of the shock absorber simulation model.

This invention discloses a method and monitoring system for calculating the flank wear of a machine tool milling cutter. The method includes establishing a flank wear model; obtaining the inherent damping ratio of the milling cutter based on hammer impact modal testing; collecting vibration acceleration signals throughout the milling cutter's lifespan and reconstructing them into single-frequency signals; synchronously measuring the flank wear during each pass; identifying the total damping ratio using the generalized zero-crossing method based on the obtained single-frequency signals and inherent damping ratio, and deriving the process damping coefficient; establishing an indentation force coefficient correction model; and obtaining a corrected flank wear calculation model based on the indentation force coefficient correction model, thus completing the online calculation of the flank wear and monitoring of the milling cutter's condition. This invention uses the above method to calculate the flank wear of the milling cutter using collected vibration acceleration signals, and corrects the model using previous pass data, achieving accurate calculation of the flank wear of the milling cutter during subsequent passes based on vibration acceleration signals.

This invention provides a design method for frequency adjustment of a rocket body wind load model. First, the target value of the first-order frequency of the wind load model is determined based on the first-order frequency of the actual rocket body erected on the launch pad and the similarity principle of the Strouhal number (Sr). The wind load model is then designed based on the target first-order frequency value. A frequency adjustment device is designed to ensure that the adjusted frequency value is between 0.9 and 1.2 times the target value. Modal tests of the wind load model are conducted outside a wind tunnel to verify whether the first-order mode of the model meets the requirements after adjustment. The model is then installed inside the wind tunnel and modal tests are performed. Through frequency adjustment, the first-order frequency of the model is ultimately guaranteed to meet the requirements. This invention solves the problems of frequency deviation between theoretical models and actual products, as well as the deviation of the first-order frequency of products with different fixed support boundaries. It ensures that the first-order bending frequency of the wind load model installed in the wind tunnel for wind testing meets the design requirements. Furthermore, this frequency adjustment device can be used for rocket wind load models of similar diameters and can be repeatedly applied to multiple models.

This invention discloses a modal testing method for an automotive intake system, comprising: installing an electromagnetic excitation device in the intake duct to drive a movable part to generate pressure pulsations through a periodic electromagnetic field to apply simulated excitation; establishing a correspondence between the excitation frequency and the electromagnetic excitation signal based on the engine speed, generating a corresponding excitation signal to achieve multi-frequency range pulsation excitation; arranging vibration response sensors and pressure sensors at at least two structural locations in the intake system to collect vibration and pressure signals; processing the signals to extract frequency response information and identify modal parameters to obtain modal characteristics. This invention can accurately reproduce the gas pulsation characteristics under actual operating conditions, avoid the fluctuation errors of traditional aerodynamic excitation, simplify the testing process, and quickly adjust parameters by combining sensor feedback, thereby improving the accuracy and efficiency of modal analysis.

This invention belongs to the field of thin-walled component working modal parameter measurement technology, and discloses a method and system for omnidirectional working modal testing of thin-walled components based on binocular vision intelligent collaborative tracking. The method includes: dimensionality reduction of measurement point data based on principal component analysis; denoising and outlier processing of the data; singular value decomposition based on the power spectral density matrix to generate a singular value spectrum; automatic identification of candidate modal frequencies in the EFDD singular value spectrum using a peak search algorithm, and automatic estimation of their half-power bandwidth to determine the fine analysis frequency band of SSI-DATA; use of an integrated machine learning clustering algorithm for automated interpretation of the stability graph; and addition of a nonlinear diagnosis and identification module for nonlinear detection. This invention constructs a more efficient, intelligent, accurate, and capable modern solution for thin-walled component working modal parameter identification in complex real-world environments, fully leveraging the enormous potential of machine vision non-contact measurement.

The application discloses a modal test point position virtual indication system and method based on augmented reality, and relates to the technical field of modal testing.The system comprises a data acquisition module, an augmented reality display module and a positioning tracking module.The data acquisition module is used for acquiring structural information and modal data of a measured object; the augmented reality display module is connected with the data acquisition module and is used for superimposedly displaying virtual test point position information on a corresponding position of a real object; and the positioning tracking module is used for tracking the relative position and posture of a device and the measured object in real time, so that the virtual test point position is accurately matched with the real object.The application improves the efficiency and accuracy of modal test point position determination, reduces errors caused by manual marking, greatly shortens the preparation time of modal testing, and simultaneously provides intuitive virtual indication by the augmented reality display module, so that an operator can more clearly understand the test point position and operation difficulty is reduced.

The utility model relates to stator test technical field discloses a kind of support device of motor stator modal test, including the erection on support of the both ends of fixed shaft separable, bearing sleeve is set on fixed shaft, and the inner ring of bearing is fixedly connected with fixed shaft, support piece annular interval is located on the outer ring of bearing, the end of support piece deviating from the outer ring of bearing is telescopic, to make it resist pressure on the inner wall surface of stator to be measured, the utility model is lifted to certain height by pedestal to stator, by the inner wall surface of stator to be measured of support piece and abut, make it be in the state of suspension, and can reduce contact area, by driving stator, the outer ring of bearing rotates relative to inner ring, to make stator can rotate around the axis of fixed shaft, to change the preset posture of stator to be measured, adapt to the needs of modal test, improve the consistency of stator modal test, robustness is strong, and can be used for a long time.

A method for analyzing the equivalent replacement and fatigue durability of high-strength steel in automotive bodies includes: calculating the thickness of the hot-formed steel replacement material using formulas for deformation resistance and energy absorption; updating the CAD model and establishing a high-precision finite element model; optimizing the model through modal testing; collecting acceleration signals from hard points on the actual vehicle and converting them into displacement signals; performing modal transient analysis and fatigue damage calculation; optimizing the structure based on the damage values ​​and evaluating the weight reduction rate and cost changes. This method can accurately determine the replacement material thickness, significantly improve simulation accuracy, greatly shorten the development cycle and verification cost, and effectively solve the fatigue durability problem of automotive bodies.

The application provides a synchronous experimental measurement system and method for cutting free surface hydrofoil fluid-structure coupling characteristics, the measurement system comprises a computer, a high-speed photography system, a fiber bragg grating demodulator, a synchronous trigger system, an acceleration data acquisition device, a three-axis acceleration sensor, a test launching water tank, a water tank base, a test launching system, a sliding device, a hydrofoil connecting structure, a cutting free surface hydrofoil, an FBG fiber string and a strain monitoring point. The measurement method comprises the following steps: 1) fiber measurement and fixation; 2) full-system synchronous triggering and data acquisition; 3) verification based on dry-wet modal testing and numerical simulation; and 4) data processing for high-speed transient process. The application effectively solves the limitations of traditional measurement technology under high-speed impact working conditions and provides strong technical support for fluid-structure coupling mechanism research.

This invention belongs to the field of aero-engine strength testing technology and provides a method for modal testing of rotor blades under variable speed conditions. The method includes: installing the rotor under test on a test platform, configuring a Doppler laser vibration measurement system and a speed sensor, and aligning the laser beam with multiple measurement points on the blade; increasing the speed at a constant rate of change, collecting vibration response signals and speed-time data at each measurement point to obtain a uniform speed reference signal set; increasing the speed at a non-constant rate of change along the same speed range, collecting variable speed vibration response signals and speed-time data at the measurement points; using the speed-time data under uniform speed conditions as a time-frequency reference, resampling and aligning the phase of the variable speed vibration signal to generate a steady-state signal; constructing a modal matrix and identifying modal parameters. This invention requires no external excitation or instantaneous speed reconstruction, has strong anti-interference capabilities, and can obtain modes under real variable speed conditions, making it suitable for dynamic characteristic testing of high-end rotating machinery such as aero-engines.

The application provides a turnout area modal parameter automatic identification method and system, relates to the technical field of turnout area modal testing, and comprises the following steps: acquiring first information, wherein the first information comprises size information of a target turnout area and a connection line length of a testing device; performing regional division processing on the target turnout area according to the first information to obtain a testing region division result; sequentially performing excitation and response measurement on each testing region according to the testing region division result and a partitioned MRIT modal testing scheme to obtain excitation-response data; performing matrix construction processing according to the excitation-response data to obtain a modal parameter stability diagram of each testing region; performing clustering processing according to the modal parameter stability diagram to obtain a clustering result; and obtaining a modal parameter identification result based on the clustering result. The application is based on a density-based spatial clustering algorithm, can automatically remove false modal and interference modal clusters, greatly improves the accuracy and efficiency of modal parameter analysis, and finally generates a modal parameter distribution of a whole turnout system.