Test optimization method for shimmy damper

Abstract

The invention discloses a test optimization method for a shimmy damper, and the method comprises the steps: simulating the working state of the shimmy damper, and obtaining the test results of a damping performance test, a high-frequency fatigue test, a sealing performance test and a running-in test of the shimmy damper; and determining the linear stiffness in the X and Y directions and the torsional stiffness in the Z direction. All parameter variables influencing the performance of the shimmy damper are collected, corresponding test performance is obtained, and key parameter variables are determined based on the random forest model; and predicting the performance of the shimmy damper based on the key parameter variables, and obtaining an optimal key parameter combination through a genetic algorithm based on the error between the predicted performance of the shimmy damper and the actual test performance, the constraint condition and the optimization target. According to the method, performance prediction and correction of the shimmy damper at the beginning of design can be achieved, the design period is shortened, and good practicability is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of oscillator testing and optimization, and specifically relates to a method for testing and optimizing oscillators. Background Technology

[0002] With the continuous development of my country's aviation industry, the quality requirements for aviation products are also constantly increasing, posing new challenges to product testing. The diversification of products makes the design and manufacturing of testing equipment increasingly complex, and the stability of testing equipment is also one of the decisive factors related to the accuracy of product performance indicators. Designing testing equipment according to product performance requirements has become an urgent issue to be addressed.

[0003] For example, shimmy dampers are used to prevent nose wheel shimmy during ground movement. Because the nose wheel can steer left and right, and the metal landing gear is an elastic body, its wheels are subjected to ground friction. If the aircraft encounters disturbances during straight-line takeoff, causing the nose wheel to deviate from its original direction of motion, the nose landing gear, under the alternating action of ground friction and its own elastic force, is likely to produce lateral shimmy oscillations around its original direction of motion. If the aircraft's takeoff speed is low, this oscillation will converge on its own and will not lead to serious consequences. However, if the aircraft speed increases to a certain value, this oscillation will tend to diverge, and the amplitude will become increasingly larger, leading to accelerated wheel wear, difficulty in controlling the takeoff direction, unclear cockpit instrument readings, and in severe cases, damage to the landing gear structure, endangering flight safety. To prevent shimmy, almost all aircraft are equipped with shimmy dampers on the nose landing gear as part of the nose wheel steering system.

[0004] With the rapid development of my country's aviation manufacturing industry, products are also becoming more diversified. Verifying the stability, durability, and other performance indicators of products is an essential verification process for product delivery. The sway damper test bench is a crucial factor in product testing. Each sway damper requires various performance tests according to design requirements (such as anti-sway damping, steering angle, starting torque check, high and low temperature tests, and break-in tests). To verify the correctness of the theory, it is necessary to control test variables according to the product's installation requirements and observe the test results. Therefore, designing a corresponding test bench becomes paramount in the testing process. Summary of the Invention

[0005] The purpose of this invention is to provide a test optimization method for oscillation dampers, which aims to solve the above-mentioned problems.

[0006] This invention is mainly achieved through the following technical solutions: A method for testing and optimizing a sway damper includes the following steps: Step S1: Set up the test fixture for the oscillation damper to simulate the actual working state of the oscillation damper and complete the torque test; use a torque sensor to detect the corresponding torque value of the torsion test; Step S2: Simulate the working state of the oscillation damper, test the oscillation damping characteristics of the oscillation damper under vibration, and obtain the test results of the damping performance test, high frequency fatigue test, sealing performance test and running-in test of the oscillation damper based on the oscillation damping damping and impact load versus time curves of the simulated oscillation damper; determine the linear stiffness in the X and Y directions and the torsional stiffness in the Z direction. Step S3: Collect various parameter variables that affect the performance of the sway damper, and repeat steps S1 and S2 to obtain the experimental performance of different parameter variables; determine the key parameter variables based on the random forest model; Step S4: Predict experimental performance based on key parameter variables. Based on the error between the predicted and actual experimental performance, as well as the constraints and optimization objectives, obtain the optimal combination of key parameters through a genetic algorithm.

[0007] To better realize the present invention, further, in step S1, the test fixture of the oscillation damper includes a base plate and an oscillation cylinder bracket arranged sequentially from front to back on the test bench. A mounting tailstock and a support seat are slidably arranged sequentially from front to back on the base plate and are fixed and locked by a locking mechanism. An oscillation cylinder is mounted on the oscillation cylinder bracket, and the output spindle of the oscillation cylinder is connected to a torque sensor via a flange. The mounting tailstock is used to mount the gear ring and the oscillation damper. A support seat is provided between the output spindle of the oscillation cylinder and the gear ring, and the support seat is used to ensure the stability of the gear ring during rotation. A central shaft is rotatably arranged inside the support seat, one end of which is connected to the torque sensor, and the other end is connected to a dial for rotating the gear ring.

[0008] To better realize the present invention, further, in step S2, a sinusoidal excitation is applied to the oscillator on a hydraulic or electromagnetic vibration table with sufficient thrust, the damping torque and angular displacement are measured, and the power diagram of the dynamic damping coefficient is calculated.

[0009] To better realize the present invention, further, in step S2, the test frequency is 15Hz for heavy bombers and transport aircraft, and 20Hz for fighter jets and small aircraft; the test amplitude is ±1°~±6°.

[0010] To better realize the present invention, further, in steps S1 and S2, the actual working state of the rotary plate damper is simulated, and the starting torque test, damping performance test, high frequency fatigue test, sealing performance test and running-in test of the rotary plate damper are carried out to evaluate the performance and reliability of the rotary plate damper.

[0011] To better realize the present invention, in step S3, the parameter variables include the structural parameters of the damper, torsional damping, and tire pressure; the key parameter variables include torsional damping and tire pressure.

[0012] The beneficial effects of this invention are as follows: (1) This invention is based on experimental testing of the oscillator's performance and obtains key parameter variables affecting actual performance using a random forest model. Then, based on existing key parameter variables and experimental performance data, a neural network is trained to obtain a target prediction model. The key parameter variables can then be input into the target prediction model to obtain the predicted performance of the oscillator. Based on the error between the predicted performance and the actual experimental performance of the oscillator, as well as the constraints and optimization objectives, the optimal combination of key parameters is obtained through a genetic algorithm. This invention can achieve performance prediction and correction of the oscillator at the initial design stage, shortening the design cycle and demonstrating good practicality.

[0013] (2) The test fixture for the oscillation damper constructed by the present invention has a simple structure and high test reliability. Specifically, the present invention installs the oscillation damper by installing a tailstock, the swing cylinder ensures the stability of the gear ring during rotation by a support seat, and the base plate enables flexible adjustment of the installation position of the oscillation damper, which has high installation reliability and good practicality. Attached Figure Description

[0014] Figure 1 This is a flowchart of the testing and optimization method for the oscillation damper of the present invention; Figure 2 A cross-sectional structural diagram of the test fixture for the oscillation damper; Figure 3 Top view of the test fixture for the oscillation damper; Figure 4 This is a two-dimensional sectional view of the support base.

[0015] The components are: 1-base plate, 2-swing cylinder, 3-swing cylinder bracket, 4-mounting tailstock, 5-support base, 51-mounting bracket, 52-central shaft, 53-pressure plate, 54-bearing, 6-flange, 7-torque sensor, 8-dial, 9-guide rail. Detailed Implementation

[0016] Example 1: A test optimization method for oscillator, such as Figure 1 As shown, it includes the following steps: (1) Set up the test fixture for the oscillation damper, simulate the actual working state of the oscillation damper, and complete the torque detection; use torque sensor 7 to detect the corresponding torque value of the torsion test; The working state of the oscillation damper was simulated, and the oscillation damping characteristics of the oscillation damper were tested under vibration. Based on the oscillation damping and impact load versus time curves of the simulated oscillation damper, the test results of damping performance test, high frequency fatigue test, sealing performance test and running-in test of the oscillation damper were obtained respectively; the linear stiffness in the X and Y directions and the torsional stiffness in the Z direction were determined.

[0017] Preferably, a sinusoidal excitation is applied to the damper on a hydraulic or electromagnetic vibration table with sufficient thrust, and the damping torque and angular displacement are measured to calculate the power diagram of the dynamic damping coefficient. Preferably, the test frequency is 15Hz for heavy bombers and transport aircraft, and 20Hz for fighter jets and small aircraft; the test amplitude is ±1° to ±6°.

[0018] (2) Collect various parameter variables affecting the performance of the sway damper, and repeat the above steps to obtain the experimental performance of different parameter variables; determine the key parameter variables based on the random forest model. Based on the existing key parameter variables and experimental performance data, train a neural network to obtain a target prediction model. Then, the key parameter variables can be input into the target prediction model to obtain the predicted performance of the sway damper. Specifically, the parameter variables include the structural parameters of the sway damper, torsional damping, and tire pressure; the key parameter variables include torsional damping and tire pressure.

[0019] (3) Input the key parameter variables into the target prediction model to predict the performance of the oscillator; based on the error between the predicted performance of the oscillator and the actual experimental performance, as well as the constraints and optimization objectives, obtain the optimal combination of key parameters through a genetic algorithm. This invention can realize the performance prediction and correction of the oscillator at the beginning of the experimental design, saving the design cycle and having good practicality.

[0020] Preferably, such as Figures 2-4 As shown, the test fixture includes a base plate 1 and a swing cylinder bracket 3 arranged sequentially from front to back on the test bench. A mounting tailstock 4 and a support seat 5 are slidably arranged sequentially from front to back on the base plate 1 and are fixed and locked by a locking mechanism. A swing cylinder 2 is mounted on the swing cylinder bracket 3, and the output spindle of the swing cylinder 2 is connected to a torque sensor 7 via a flange 6. The mounting tailstock 4 is used to mount a gear ring and a damper. A support seat 5 is provided between the output spindle of the swing cylinder 2 and the gear ring to ensure the stability of the gear ring during rotation. A central shaft 52 is rotatably mounted inside the support seat 5. One end of the central shaft 52 is connected to the torque sensor 7, and the other end is connected to a dial 8 that rotates the gear ring.

[0021] The swing cylinder 2 is connected to the test bench via the swing cylinder bracket 3, and the output spindle of the swing cylinder 2 passes through the swing cylinder bracket 3 and is connected to the torque sensor 7 via the flange 6.

[0022] The support base 5 includes a mounting bracket 51, a central shaft 52, and a pressure plate 53. The mounting bracket 51 is fixedly connected to the base plate 1. The central shaft 52 is rotatably mounted in the middle of the mounting bracket 51. Both ends of the central shaft 52 are rotatably connected to the mounting bracket 51 via bearings 54. One end of the central shaft 52 near the swing cylinder 2 is connected to the mounting bracket 51 via a pressure plate, and the other end is provided with a mounting end face corresponding to the dial 8.

[0023] A guide rail 9 is mounted on the top of the base plate 1, and the bottoms of the mounting tail 4 and the support base 5 are slidably connected to the guide rail 9 to facilitate the installation of the sway damper. Several locking holes are provided on the periphery of the mounting tail 4 and the support base 5, and locking screws pass through the locking blocks and are connected to the base plate 1.

[0024] In order to ensure the stability of the sway damper's gear ring rotation during use, a support base 5 is added to the gear ring and output part. One end of the central shaft 52 is connected to a torque sensor 7, and the other end is connected to a dial 8 for rotating the gear ring. Bearings 54 are installed at both ends of the central shaft 52, and the above parts are fixed by a mounting bracket 51 and connected to the base plate 1. The mounting tailstock 4 is used to install the gear ring and the main body of the sway damper. The shaft of the mounting tailstock 4 is used to achieve alignment detection with the support base 5, and the groove at the top is used to fix the sway damper. The gear ring is the driving component on the sway damper. This invention fixes the sway damper by mounting tailstock 4 and makes the sway damper move in linkage by swing cylinder 2, simulating the angle and force conditions during aircraft operation, thereby realizing the testing of the sway damper's performance.

[0025] The experimental fixture for the oscillation damper constructed by this invention has a simple structure and high testing reliability. Specifically, the oscillation damper is installed by mounting the tailstock 4, the swing cylinder 2 is supported by the support base 5 to ensure the stability of the gear ring during rotation, and the mounting position of the oscillation damper can be flexibly adjusted by the base plate 1, which has high installation reliability and good practicality.

[0026] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for testing and optimizing a oscillation damper, characterized in that, Includes the following steps: Step S1: Set up the test fixture for the oscillation damper to simulate the actual working state of the oscillation damper and complete the torque test; use a torque sensor to detect the corresponding torque value of the torsion test; Step S2: Simulate the working state of the oscillation damper, test the oscillation damping characteristics of the oscillation damper under vibration, and obtain the test results of the damping performance test, high frequency fatigue test, sealing performance test and running-in test of the oscillation damper based on the oscillation damping damping and impact load versus time curves of the simulated oscillation damper; determine the linear stiffness in the X and Y directions and the torsional stiffness in the Z direction. Step S3: Collect various parameter variables that affect the performance of the sway damper, and repeat steps S1 and S2 to obtain the experimental performance of different parameter variables; determine the key parameter variables based on the random forest model; Step S4: Predict the performance of the oscillator based on key parameter variables. Based on the error between the predicted performance and the actual experimental performance of the oscillator, as well as the constraints and optimization objectives, obtain the optimal combination of key parameters through a genetic algorithm.

2. The method for testing and optimizing a sway reducer according to claim 1, characterized in that, In step S1, the test fixture for the oscillation damper includes a base plate and a swing cylinder bracket arranged sequentially from front to back on the test bench. A mounting tailstock and a support seat are slidably arranged sequentially from front to back on the base plate and are fixed and locked by a locking mechanism. A swing cylinder is mounted on the swing cylinder bracket, and the output spindle of the swing cylinder is connected to a torque sensor via a flange. The mounting tailstock is used to mount the gear ring and the oscillation damper. A support seat is provided between the output spindle of the swing cylinder and the gear ring to ensure the stability of the gear ring during rotation. A central shaft is rotatably mounted inside the support seat. One end of the central shaft is connected to the torque sensor, and the other end is connected to a dial for rotating the gear ring.

3. The test optimization method for a sway reducer according to claim 1 or 2, characterized in that, In step S2, a sinusoidal excitation is applied to the oscillator on a hydraulic or electromagnetic vibration table with sufficient thrust, the damping torque and angular displacement are measured, and the power diagram of the dynamic damping coefficient is calculated.

4. The method for testing and optimizing a sway reducer according to claim 3, characterized in that, In step S2, the test frequency is 15Hz for heavy bombers and transport aircraft, and 20Hz for fighter jets and small aircraft; the test amplitude is ±1° to ±6°.

5. The test optimization method for a sway reducer according to claim 3, characterized in that, Steps S1 and S2 simulate the actual working state of the rotary plate damper, and carry out starting torque testing, damping performance testing, high frequency fatigue testing, sealing performance testing, and break-in testing of the rotary plate damper to evaluate its performance and reliability.

6. The method for testing and optimizing a sway reducer according to claim 1, characterized in that, In step S3, the parameter variables include the structural parameters of the damper, torsional damping, and tire pressure; the key parameter variables include torsional damping and tire pressure.

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