A calibration method of an engine test bed

Abstract

The application discloses a kind of calibration methods of engine test bed, it is related to engine testing equipment technical field, comprising the following steps, S1: first, engine is installed on test bed movable frame;S2: the bearing capacity between test bed movable frame and test bed fixed frame is detected by standard sensor, and signal cable is detected output to standard force sensor signal measuring instrument and is recorded;S3: the bearing capacity value recorded by standard force sensor signal measuring instrument is transmitted to controller;S4: after the current stress state of test bed movable frame is obtained according to the detection value of standard sensor, the required calibration appropriate pressure value is calculated according to algorithm;S5: controller sends electric signal and makes in situ calibration unit run, and the appropriate pressure value between test bed movable frame and test bed fixed frame is adjusted by in situ calibration unit running.Adjustment is carried out to the appropriate pressure value between test bed movable frame and test bed fixed frame by in situ calibration unit running, to realize the static calibration and check of working sensor to simulate actual working condition, and the input-output characteristic equation of working sensor is obtained.

Description

Technical Field

[0001] This invention relates to the field of engine testing equipment technology, specifically to a calibration method for an engine test bench. Background Technology

[0002] During flight, aircraft engines need to ensure the stability of their thrust. If there is a deviation in the output thrust of the engine during flight, it will cause a significant change in the flight trajectory of the aircraft and will also increase the torque pressure that the aircraft needs to bear. Therefore, during the development of aircraft engines, it is necessary to test the engine to ensure the rationality and stability of the engine settings. However, during engine testing, errors may occur due to the layout conditions of the test stand and the deformation of the moving frame. Therefore, the existing technology needs to provide a method for calibration on the engine test stand. Summary of the Invention

[0003] The purpose of this invention is to provide a calibration method for an engine test bench, addressing the shortcomings of existing technologies.

[0004] To achieve the above objectives, the present invention adopts the following solution:

[0005] In this application, the engine is installed in the mounting frame, and then the engine is started. The power generated during engine operation is transmitted to the force measuring component. The force measuring component collects the tensile force values ​​generated during engine operation to obtain engine operating data. By using axial force measuring devices, horizontal force measuring devices, and vertical force measuring devices, the forces in various directions of the engine can be measured separately, thereby summarizing the various torques measured during engine operation.

[0006] The test bench needs to be calibrated before the test run.

[0007] Includes the following steps,

[0008] S1: First, install the engine on the test bench frame;

[0009] S2: The load-bearing capacity between the moving frame and the stationary frame of the test bench is measured by a standard sensor, and the detection output is transmitted to the standard force sensor signal measuring instrument for recording via a signal cable;

[0010] S3: Transmit the load-bearing capacity value recorded by the standard force sensor signal measuring instrument to the controller;

[0011] S4: After the controller obtains the current stress state of the test bench moving frame based on the detection values ​​of the standard sensors, it calculates the appropriate pressure value to be calibrated according to the algorithm.

[0012] S5: The controller sends an electrical signal to activate the in-situ calibration unit, which adjusts the appropriate pressure value between the moving frame and the stationary frame of the test bench.

[0013] Furthermore, the in-situ calibration unit includes a speed-regulating motor, an auxiliary control device, and a main oil cylinder. The controller is electrically connected to the speed-regulating motor, and the speed-regulating motor is connected to the auxiliary control device via a hydraulic pipeline. The main oil cylinder is equipped with hydraulic cylinders at both ends that are connected to the auxiliary control device. The controller outputs an adjustment signal to the speed-regulating motor, and the speed-regulating motor drives the auxiliary control device when it runs. The auxiliary control status controls the hydraulic oil to be regulated in the main oil cylinder.

[0014] Furthermore, the auxiliary control device includes an oil pump station and an accumulator. The pressure oil in the oil pump station is input and output in the main oil cylinder by a speed regulating motor, thereby realizing the calibration of the test bench moving frame.

[0015] Furthermore, a manual fine-tuning valve is installed in the auxiliary control device. This allows operators to manually adjust the main hydraulic cylinder, thereby increasing the equipment's adjustability.

[0016] Furthermore, a universal flexible component is provided at each end of the working sensor, which can achieve high load-bearing capacity and low rotational stiffness, thereby improving the detection accuracy of this application.

[0017] Furthermore, the standard sensor and the working sensor are coaxially arranged, and the axial angle and position of the working sensor and the standard sensor need to be measured and calibrated before the experiment.

[0018] Furthermore, the range of the standard sensor is ±125kN.

[0019] Furthermore, the range of the working sensor is ±250kN.

[0020] The advantages of this invention compared to the prior art are:

[0021] The method described in this application is used to calibrate the working sensor before engine hot testing using a known standard force. The effect of the standard force on the working sensor is equivalent to the effect of the engine thrust vector on the working sensor. First, the hydraulic control system applies the vector force to the loading cylinder, and its value is measured by a standard force sensor. After stabilization, the azimuth angle of the straight line formed by marked points A and B on the steel wire rope is measured using a theodolite, thereby calculating the values ​​of each component of the vector force. Finally, this value is compared with the measurement value on the test bench, which serves as a verification function to perform static calibration and verification of the working sensor under simulated actual working conditions, and to obtain the input-output characteristic equation of the working sensor. Attached Figure Description

[0022] Figure 1 A flowchart illustrating the calibration method for an engine test bench;

[0023] Figure 2 This is a schematic diagram of an engine test bench. Detailed Implementation

[0024] A calibration method for an engine test bench includes the following steps:

[0025] S1: First, install the engine on the test bench frame;

[0026] S2: The load-bearing capacity between the moving frame and the stationary frame of the test bench is measured by a standard sensor, and the detection output is transmitted to the standard force sensor signal measuring instrument for recording via a signal cable;

[0027] S3: Transmit the load-bearing capacity value recorded by the standard force sensor signal measuring instrument to the controller;

[0028] S4: After the controller obtains the current stress state of the test bench moving frame based on the detection values ​​of the standard sensors, it calculates the vector pressure value that needs to be calibrated according to the algorithm.

[0029] S5: The controller sends an electrical signal to activate the in-situ calibration unit, which adjusts the vector pressure value between the moving frame and the stationary frame of the test bench.

[0030] The in-situ calibration unit includes a speed-regulating motor, an auxiliary control device, and a main oil cylinder. The controller is electrically connected to the speed-regulating motor, and the speed-regulating motor is connected to the auxiliary control device via a hydraulic pipeline. The main oil cylinder has hydraulic cylinders at both ends that are connected to the auxiliary control device. The controller outputs adjustment signals to the speed-regulating motor, and the speed-regulating motor drives the auxiliary control device when it runs. The auxiliary control device controls the hydraulic oil to flow into the main oil cylinder for adjustment. The auxiliary control device includes an oil pump station, an accumulator, and a manual fine-tuning valve.

[0031] The standard sensor uses the Interface 11001020 and 1120 (20181108) series force sensors for tensile and compressive force measurement. These sensors are widely used in various static and dynamic measurement applications and offer extremely high accuracy. The main technical parameters are as follows:

[0032] ● Measuring range: ±250-125kN (main thrust, type 11201020), ±100kN (horizontal lateral force and vertical lateral force, type 1120);

[0033] ●Accuracy class: 0.04 (±125kN range) / 0.035 (±100kN range);

[0034] ● Output signal: Sensitivity 4mV / V;

[0035] ●Operating temperature range: -55℃~+90℃;

[0036] ●Overload: 150%

[0037] The working sensor uses the Interface 1220 force sensor from the USA for tensile and compressive force measurement. It is widely used in various static and dynamic measurement applications and boasts extremely high accuracy. The main technical parameters are as follows:

[0038] ● Measuring range: ±250kN (main thrust, type 1220), ±100kN (vertical and horizontal lateral forces, type 1220);

[0039] ●Accuracy level: 0.04;

[0040] ● Output signal: Sensitivity 14mV / V;

[0041] ●Operating temperature range: -5530℃~+9085℃;

[0042] ●Overload: 150%.

[0043] The working sensor is provided with a universal flexible component at each end. The universal flexible component consists of two sets of main spring plates and four support spring plates. The two sets of main spring plates are arranged perpendicularly to each other and provide deflection in one direction. Their combined motion is universal motion. The advantages of the universal flexible component are: (1) high efficiency, which can simultaneously obtain high load-bearing capacity and low rotational stiffness; (2) close to the ideal "ball joint" with no friction, no gaps, and constant rotation center; (3) compact structure, small size, good dynamic performance, good stability, and safe and reliable.

[0044] Layout parameters of universal flexible components in various directions:

[0045] Main thrust direction:

[0046] The stiffness of the omnidirectional flexible component is 1.25 × 10⁶ N / mm, the stiffness of the working sensor is 3.125 × 10⁶ N / mm, and the stiffness K of the force measuring component is 0.52 × 10⁶ N / mm; the total stiffness is approximately 0.3 × 10⁶ N / mm. The natural frequency in the direction of the main thrust is f = 0.159(2K / m)0.5 = 42.255.6 Hz.

[0047] Direction of horizontal lateral force:

[0048] The stiffness of the omnidirectional flexible component is 8.33 × 10⁵ N / mm, the stiffness of the working sensor is 1.67 × 10⁶ N / mm, and the stiffness K of the force measuring component is 0.33 × 10⁶ N / mm; the total stiffness is approximately 0.223 × 10⁶ N / mm. The natural frequency in the direction of the main thrust is f = 0.159(2K / m)⁰.⁵ = 29.0335.3 Hz.

[0049] Direction of vertical lateral force:

[0050] The stiffness of the omnidirectional flexible component is 8.33 × 10⁵ N / mm, the stiffness of the working sensor is 1.67 × 10⁶ N / mm, and the stiffness K of the force measuring component is 0.33 × 10⁶ N / mm. The natural frequency in the direction of the main thrust is f = 0.159(3K / m)0.5 = 43.2 Hz.

[0051] The standard sensor and the working sensor are set coaxially. Before the experiment, the axial angle and position of the working sensor and the standard sensor need to be measured and calibrated. During the installation and debugging process, the working sensor and the standard sensor are tested to be coaxial with the moving frame using a mandrel. The difference between the diameter of the mandrel and the diameter of the detection hole is less than 0.1 mm, and the surface finish of the mandrel and the detection hole is 1.6.

[0052] The main technical parameters of the in-situ calibration device are as follows:

[0053] ● Each level loads in approximately 30 seconds;

[0054] ● The power source accuracy is better than 0.05%FS;

[0055] ●Power source fluctuation is better than 0.05%FS;

[0056] ●Working modes: manual and automatic.

[0057] The advantages of the in-situ calibration device are: (1) the standard force value can be continuously changed, and the calibration of any point can be completed within the thrust range; (2) the calibration process is automated, the work efficiency is high, the labor intensity of operators is reduced, and they are kept away from the unsafe area of ​​the test site; (3) the in-situ calibration can be carried out immediately after the engine hot test.

[0058] The standard sensor has a range of ±125kN, and the working sensor has a range of ±250kN.

[0059] The main sources of error in the measurement of vector thrust components include two aspects: sensors and structural components.

[0060] 1) Measurement error in the sensor component

[0061] Based on the accuracy of the working sensor, and using the root mean square error synthesis method, the theoretical measurement errors of the sensor components are obtained as follows: ±0.057%FS (main thrust), ±0.057%FS (horizontal lateral force), and ±0.069%FS (vertical lateral force).

[0062] In practice, due to installation, mutual interference, and other error factors, the measurement error of the sensor component is generally based on the in-situ calibration results. According to empirical data, the practical measurement errors of the sensor component are ±0.2%FS (main thrust) and ±0.5%FS (lateral force).

[0063] 2) Measurement error of structural components

[0064] Summary of measurement errors in structural components:

[0065]

[0066] Vector force simulation requires perfect consistency in the magnitude, direction, and point of application of the force. Since the point of application of aero-engine thrust is difficult to determine, and considering factors such as cost, ease of use, and implementation, a simulation scheme with a fixed direction and variable magnitude is adopted. The upper limit of the force magnitude is (250² + 100² + 100²)⁰.⁵ = 287.2 kN, and the upper limits of the azimuth angles of the force's line of action are α = cos⁻¹(250 / 287.2) = 29.5° and β = γ = cos⁻¹(100 / 287.2) = 69.6°, respectively.

[0067] The location of the installation foundation is determined with reference to azimuth angles α, β, and γ. The standard force sensor used is the Interface 12321132 model from the US company, with a range of ±450 kN (accuracy class: 0.05; other performance specifications are described in section 4.2). The standard axial force sensor used is the Interface 1120 model from the US company, with a range of ±250 kN (accuracy class: 0.035; other performance specifications are described in section 4.2). The standard force sensors are connected in series between steel wire ropes. The advantage of using flexible steel wire ropes is that it minimizes disruption to the original constraint structure of the test bench (the stiffness of the steel wire ropes is much lower than the structural stiffness of the test bench).

[0068] The principle of vector thrust measurement is as follows: Utilizing the principle of rigid body equilibrium, several constraints are appropriately arranged to limit the six degrees of freedom (three translational and three rotational) of the test product, bringing it to a state of static equilibrium. Based on the conditions of rigid body force equilibrium... By measuring the individual components of the thrust vector, the magnitudes of the three components and their moments, as well as the eccentricity angle and eccentricity, of the thrust vector in the moving frame coordinate system can be determined.

[0069] Depending on the position of the test product during installation, there are two methods for measuring multi-component forces: horizontal and vertical. The former is advantageous for measuring the magnitude of the component forces (especially the axial and horizontal components), while the latter is advantageous for measuring thrust eccentricity (the measurement of the horizontal lateral component force is not affected by the weight of the test product and its changes).

[0070] This test stand only requires the measurement of the three components of the thrust vector, and does not involve the measurement of torque, thrust eccentricity, and eccentricity angle. In addition, considering the characteristic that the center of gravity of the aero-engine remains basically unchanged during operation, as well as the structural stability and stress rationality of the test stand, it is proposed to adopt a test stand structure that takes into account both seven and nine components of the thrust vector.

[0071] In the construction of the test bench, the frame mainly consists of several load-bearing columns and their reinforcing beams. The load-bearing columns are pre-embedded bolts on the foundation of the test room roof. They have mounting surfaces for force measuring components and standard force loading components, as well as mounting and adjustment reference surfaces.

[0072] The moving frame mainly consists of a "U"-shaped frame and an engine adapter frame. The gantry frames at both ends of the "U"-shaped frame have mounting surfaces for force measuring components and standard force loading components. The "U"-shaped frame is equipped with an installation and adjustment reference surface. The engine adapter frame is rigidly connected to the "U"-shaped frame by bolts and locating pins, and the engine under test is mounted on the engine adapter frame. The mass of the moving frame is tentatively set at 5000 kg, and the coordinate system of the moving frame is established on the cross section of any gantry frame.

[0073] The force measuring components are installed between the moving frame and the fixed frame. For the seven-component test bench, the main thrust and horizontal force measuring components are arranged in the horizontal plane passing through the engine centerline. One vertical force measuring component is arranged in the vertical plane passing through the engine centerline, and the other two are arranged symmetrically (in the vertical plane). Each force measuring component consists of two universal flexible parts and one working sensor.

[0074] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0075] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0076] In the description of this invention, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A calibration method for an engine test bench, characterized in that, Includes the following steps, S1: First, install the engine on the test bench frame; S2: The load-bearing capacity between the moving frame and the stationary frame of the test bench is measured by a standard sensor, and the detection output is transmitted to the standard force sensor signal measuring instrument for recording via a signal cable; S3: Transmit the load-bearing capacity value recorded by the standard force sensor signal measuring instrument to the controller; S4: After the controller obtains the current stress state of the test bench moving frame based on the detection values ​​of the standard sensors, it calculates the appropriate pressure value to be calibrated according to the algorithm. S5: The controller sends an electrical signal to make the in-situ calibration unit run, and adjusts the appropriate pressure value between the moving frame and the stationary frame of the test bench through the operation of the in-situ calibration unit. The in-situ calibration unit includes a speed-regulating motor, an auxiliary control device, and a main oil cylinder. The controller is electrically connected to the speed-regulating motor, and the speed-regulating motor is connected to the auxiliary control device via a hydraulic pipeline. The main oil cylinder is equipped with hydraulic cylinders at both ends that are connected to the auxiliary control device. The controller outputs an adjustment signal to the speed-regulating motor. When the speed-regulating motor is running, it drives the auxiliary control device. The auxiliary control status controls the hydraulic oil to be regulated in the main oil cylinder. The auxiliary control device includes an oil pump station and an accumulator; The standard sensor and the working sensor are set coaxially. Before the experiment, the axial angle and position of the working sensor and the standard sensor need to be measured and calibrated. A universal flexible component is provided at each of the two ends of the working sensor.

2. The calibration method for an engine test bench according to claim 1, characterized in that, A manual fine-tuning valve is installed in the auxiliary control device.

3. The calibration method for an engine test bench according to claim 1, characterized in that, The standard sensor has a measurement range of ±125kN.

4. The calibration method for an engine test bench according to claim 1, characterized in that, The range of the working sensor is ±250kN.

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