Continuous force measurement and calculation method for spoke type track wheel

Abstract

The invention provides a continuous force measurement and calculation method for a spoke type track wheel, and relates to the technical field of wheel-rail force measurement, and the method comprises the steps: uniformly arranging a plurality of strain gauges which are connected to form a bridge circuit on the spoke type track wheel; through a bridge circuit output signal, calculating strain distribution under the action of a unit vertical force, and obtaining an actual vertical force under an external acting force; through superposition and correction of bridge circuit output signals, a transverse force is obtained, and continuous force measurement and calculation of the spoke type track wheel are completed. According to the invention, through carrying out data acquisition on the track wheels and optimizing a resolving algorithm, the force measuring device can rapidly respond to the change of the wheel-rail force, realizes continuous measurement of the wheel-rail force, ensures the real-time performance and the accuracy of test data, and is suitable for various research scenes such as a railway vehicle dynamics test and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of wheel-rail force measurement, and in particular relates to a spoke-type rail wheel continuous force measurement and solution method. Background Art

[0002] With the development of railway transportation technology, wheel-rail force has received extensive attention as an important parameter to measure the operating status of railway vehicles, the health of tracks and the safety performance of trains. Wheel-rail force refers to the interaction force between wheels and rails. This force is transmitted to the bogie and the car body through the wheel suspension system, and has a direct impact on the lateral stability, riding comfort, wheel-rail wear and derailment safety of the vehicle. The size of the wheel-rail force not only affects the safety and riding comfort of the vehicle, but also plays an important role in the life of the track and the maintenance frequency.

[0003] The current mainstream wheel-rail force measurement methods include the force measurement wheelset method based on axle strain, the measurement method based on rail waist strain, and the non-contact method of indirect measurement of wheel-rail force.

[0004] In the laboratory, strain gauges are often placed at specific locations on wheels or axles to achieve real-time measurement of wheel-rail force. This is a relatively mature traditional force measurement method for measuring vehicle wheel-rail interaction force.

[0005] The core of this method is to use strain gauges to convert the physical strain of the wheel into electrical signals, and then calculate the force between the wheel and the track. However, there are still some obvious shortcomings and limitations in practical applications, as follows:

[0006] Low applicability. The traditional wheel-rail force measurement method has certain limitations when measuring different vehicle speeds, vehicle models and frequencies. Since strain gauges must be arranged at specific positions on wheels or axles, the wheel structures and materials of different vehicle models are different, making it difficult for the traditional wheel-rail force measurement method to be used on different types of vehicles. During the measurement process of high-speed trains, the traditional wheel-rail force measurement method may also be affected by the high-speed changes in the wheel-rail contact point and cannot accurately capture the real-time changing mechanical data.

[0007] Low measurement sensitivity. In the traditional wheel-rail force measurement method, although the strain gauge can capture the changes in wheel-rail force, for the radial-plate wheel, the wheel strain under the vertical force is small and the sensitivity is low, resulting in the strain gauge's insufficient accuracy in vertical force measurement, unable to accurately reflect the actual force between the wheel and rail, and unable to accurately capture the dynamic characteristics of the vehicle at high speed.

[0008] No phase angle solution leads to large errors. The existing traditional wheel-rail force measurement method usually ignores the phase angle information of the wheel-rail contact point when calculating the wheel-rail force. This means that the traditional wheel-rail force measurement method can only obtain the amplitude information of the strain signal, and cannot reflect the direction and angle changes of the actual force on the wheel during rotation. Since the wheel-rail force is a dynamically changing quantity, ignoring the phase angle information may lead to insufficient accuracy of the calculation results, especially in high-speed trains, this error is more obvious. In addition, due to the limitations of the strain gauge installation position and the complexity of the wheel material, the wheel-rail force calculated by the traditional wheel-rail force measurement method may deviate significantly from the actual force, and cannot meet the engineering applications with high precision requirements.

[0009] The test installation is complex. The traditional wheel-rail force measurement method requires the installation of strain gauges at key locations on the axle or wheel, which is usually a cumbersome installation process and requires highly precise calibration. When measuring the wheel-rail forces of different vehicle models, the strain gauges need to be repeatedly installed, adjusted, and calibrated, which greatly increases the complexity and cost of the test. In addition, the complex operating environment of the wheels and axles may affect the stability of the strain gauges, resulting in measurement errors.

[0010] Strain gauges are easily damaged. Since the wheels and axles are subjected to complex dynamic loads during the test, strain gauges are easily affected by factors such as vibration, shock, and temperature changes. Especially under random load conditions, the life and stability of the sensor will be seriously affected. This damage may lead to inaccurate measurement data and increase the maintenance cost of the equipment.

[0011] In summary, although the traditional measurement method has solved the problem of wheel-rail force measurement to a certain extent, it has many limitations. First, the traditional method requires the installation of a large number of sensors on the vehicle axle or track, which makes the measurement process complicated, the test cost high, and the installation and calibration inconvenient. Secondly, since the contact point between the wheel and the track changes continuously as the wheel rotates, it is extremely challenging to measure the force at the wheel-rail contact point in real time. During the test, the dynamic changes of the wheel-rail contact point are simulated to ensure the measurement accuracy of the wheel-rail force.

[0012] Therefore, there is an urgent need for a high-precision, easy-to-operate continuous measurement and solution method for wheel-rail force, so as to better meet the demand for high-precision measurement of wheel-rail force in experiments. Summary of the invention

[0013] In view of the above-mentioned deficiencies in the prior art, the present invention provides a continuous force measurement and solution method based on a spoke-type rail wheel to solve the above-mentioned problems.

[0014] In order to achieve the above purpose, the technical solution adopted by the present invention is: a spoke type rail wheel continuous force measurement and solution method, the spoke type rail wheel continuous force measurement and solution method is applied to a rail wheel force measuring device, comprising the following steps:

[0015] A plurality of strain gauges connected into a bridge circuit are evenly arranged on the spoke rail wheel; the strain distribution under the action of unit vertical force is calculated through the output signal of the bridge circuit, and the actual vertical force under the external force is obtained; the lateral force is obtained by superimposing and correcting the output signal of the bridge circuit, thereby completing the continuous force measurement and solution of the spoke rail wheel.

[0016] Furthermore, a plurality of strain gauges connected into a bridge circuit are evenly arranged on the rail wheel: a vertical force measurement bridge circuit: a plurality of strain gauges are arranged at the inflection points of the spoke plates to obtain strain changes under the action of vertical force, wherein the strain gauges are connected through a full-bridge circuit; a lateral force measurement bridge circuit: a plurality of strain gauges are arranged at the ends of the spoke plates and the straight plates to eliminate interference of the vertical force on the lateral force measurement.

[0017] Furthermore, the rail wheel force measuring device includes a rail wheel and a strain gauge; the strain gauge is arranged on the rail wheel, the spoke plate of the rail wheel adopts a half-spoke design, and fan-shaped openings are arranged on the spoke plate.

[0018] Beneficial effects of the present invention:

[0019] The present invention is based on a track wheel force measuring device and phase angle solution technology. By properly arranging strain gauges on the spoke plate, the wheel-rail force at the contact point between the wheel and the track can be accurately measured, especially in the measurement of vertical force and lateral force, with extremely high sensitivity and accuracy. The present invention can not only simplify the test process and reduce the repeated installation of test equipment, but also improve the measurement accuracy, reduce the test cost, and provide more reliable wheel-rail force measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the plan for drilling holes in the track wheel.

[0021] Figure 2 Optimization diagram for the fan-shaped opening of the track wheel.

[0022] Figure 3 Schematic diagram of strain gauge location and bridge circuit.

[0023] Figure 4 Schematic diagram of strain distribution under unit vertical force.

[0024] Figure 5 Schematic diagram of strain distribution under lateral force and bending moment.

[0025] Figure 6 This is a schematic diagram of the measurement point layout and bridge circuit.

[0026] Figure 7 This is a schematic diagram of the comparison of results under unit load.

[0027] Figure 8Schematic diagram of comparison of results under random load (no eccentricity).

[0028] Fig. 9 Schematic diagram of comparison of results under random load (with eccentricity).

[0029] Fig.10 Schematic diagram of the effect of eccentricity on the measured wheel-rail force.

[0030] Fig.11 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0032] Example

[0033] like Fig.11 As shown, the present invention provides a spoke type rail wheel continuous force measurement and solution method, the spoke type rail wheel continuous force measurement and solution method is applied to a rail wheel force measuring device, and the implementation method is as follows:

[0034] S1. Multiple strain gauges connected into a bridge circuit are evenly arranged on the spoke-type rail wheel, specifically:

[0035] Vertical force measurement bridge: multiple strain gauges are arranged at the inflection points of the spokes to obtain the strain changes under the vertical force, where the strain gauges are connected through a full bridge circuit;

[0036] Transverse force measurement bridge: multiple strain gauges are arranged at the ends of the spoke plates and the straight plates to eliminate the interference of vertical force on the transverse force measurement;

[0037] S2. Calculate the strain distribution under the unit vertical force through the bridge output signal, and obtain the actual vertical force under the external force;

[0038] S3. By superimposing and correcting the output signal of the bridge circuit, the lateral force is obtained, and the continuous force measurement and solution of the spoke-type rail wheel are completed.

[0039] In this embodiment, the rail wheel force measuring device includes a rail wheel and a strain gauge; the strain gauge is arranged on the rail wheel.

[0040] The spoke plate of the rail wheel adopts a half-spoke design and is provided with openings on the spoke plate; the strain gauge is arranged at the inflection point of the spoke plate; the strain gauge is arranged at the end of the spoke plate and the straight plate; the openings on the spoke plate are fan-shaped.

[0041] In this embodiment, the rail wheel force measuring device of the present invention constructs a high-precision, stable and sensitive wheel-rail force measurement system by designing the rail wheel and strain gauge arrangement. The system can continuously measure and calculate the wheel-rail force under complex working conditions such as random loads and eccentricity, and improve the measurement accuracy through phase angle solution technology, which is suitable for various research scenarios such as railway vehicle dynamics tests. The specific structure is as follows:

[0042] The track wheel is one of the core components of the force measuring device. Its main function is to simulate the contact relationship between the wheel and the track and measure the wheel-rail force through the strain gauge. The design of the track wheel is based on the principle of "assuming that the wheel is stationary and the track rotates around the wheel". This design simplifies the mechanical analysis during the test and improves the accuracy of the measurement.

[0043] The track wheel is forged from track steel, and the wheel rim is designed with an inclination angle of 1:40 to simulate the working state of a real wheel on the track. The spoke plate of the track wheel adopts a half-spoke design, and holes are opened at key positions to improve the sensitivity of the strain signal. The shape of the opening is precisely designed to increase the output of the strain signal while maintaining the structural strength of the track wheel.

[0044] There are multiple strain gauges evenly distributed on the outer surface of the rail wheel to measure the changes in wheel-rail forces in different directions. By collecting and processing the signals of these strain gauges, the mechanical effects of the wheel in the vertical, lateral and longitudinal directions can be calculated.

[0045] In this embodiment, the optimization design of the semi-spoke type force measuring rail wheel of the present invention is mainly carried out around the following four aspects: hole scheme optimization, hole sector optimization and track wheel strength calculation of optimized sector-shaped holes. These optimization designs are intended to improve the strain sensitivity and structural strength of the rail wheel during the wheel-rail force measurement process, while ensuring that it has sufficient load-bearing capacity and reliability under high loads.

[0046] 1. Optimization of hole opening scheme

[0047] Problems with existing spoke plate design: In traditional spoke plate design, the spoke plate is usually solid. This design shows small radial strain under high load, resulting in insufficient measurement sensitivity. When the applied force is small, the strain of the spoke plate is not obvious, and sufficient strain signals cannot be obtained, affecting the accuracy of the measurement. Therefore, it is necessary to increase the output signal of the strain by opening holes in the spoke plate, thereby improving the measurement sensitivity.

[0048] Optimization process: In order to improve the output of strain signals, the present invention makes holes in the spoke plate, such as Figure 1 As shown. Through finite element analysis, the strain and stress distribution of the spoke plate without holes and with different holes are compared. The results show that the radial strain of the spoke plate without holes under the action of vertical force is very small, and it is difficult to capture enough signals through strain gauges, and the sensitivity is low. Therefore, the solution of making appropriate holes in the spoke plate is adopted to increase the output of strain signals.

[0049] The finite element results are as follows: Under the action of the vertical force Q = 10kN, the radial strain of the spoke plate after the hole is opened increases significantly. Specific data show that the radial strain of the spoke plate without holes is 3.1με, while after the hole is opened, the radial strain increases to 7.7με, as shown in Table 1. In addition, the maximum radial stress under the lateral force Y = 10kN increases from 16.4MPa to 17.4MPa. Although it has increased, it is still lower than the safety limit of 18MPa. Therefore, the hole opening scheme is considered feasible.

[0050] Table 1 Stress analysis results of the schemes without holes and with holes

[0051]

[0052] 2. Opening fan shape optimization

[0053] Problems with traditional spoke plate design: Although the openings in the spoke plate can improve strain output, the shape, size and position of the openings have a significant impact on the sensitivity of the strain signal. The traditional circular opening design has limited effect on amplifying the strain signal, especially under the action of lateral force, stress concentration is prone to occur at the opening, affecting the structural strength of the spoke plate.

[0054] Optimization process: In order to solve this problem, the present invention further optimizes the opening shape of the spoke plate, such as Figure 2 By comparing the strain distribution of circular and fan-shaped openings, it is found that the fan-shaped opening can more effectively amplify the strain signal and reduce the stress concentration phenomenon under the action of lateral force.

[0055] Finite element results: As shown in Table 2, after the opening shape changes from circular to fan-shaped, the radial strain under the vertical force Q = 10kN increases from 11.5με to 11.9με, and under the lateral force Y = 10kN, the maximum strain position is transferred from the opening to the middle and lower part of the spoke plate, and the radial strain decreases from 97.2με to 72.7με. The maximum stress decreases from 20.3MPa to 15MPa, which is still lower than the safety limit of 18MPa, showing better mechanical properties. The solution is basically determined to be a fan-shaped opening.

[0056] Optimization results: The fan-shaped opening design not only improves the strain output under the vertical force, but also effectively reduces the stress concentration under the lateral force, ensuring the stability of the spoke plate under high load. The finite element results show that the stress distribution of the spoke plate with fan-shaped opening design is more uniform under the lateral force, and the structural strength is significantly improved.

[0057] Table 2 Stress analysis results of different opening shapes

[0058]

[0059] 3. Optimized fan-shaped opening - track wheel strength design

[0060] The spoke plate needs to bear loads from different directions during actual operation. Therefore, after structural optimization, the strength of the optimized rail wheel must be calculated to ensure its safety and stability under various working conditions.

[0061] Optimization process: The optimized fan-shaped opening design was further verified by finite element analysis to verify its strength under vertical and lateral forces. The specific calculation method is to apply loads at different angles on the spoke plate, with an interval of 15° and 22.5° as one working condition, and calculate its equivalent stress and principal stress distribution within the range of 0° to 360°. In the test, the vertical force Q = 200kN, the lateral force Y = 80kN, and the eccentricity E is 10mm. The strength analysis was performed by simulating the most unfavorable working condition.

[0062] Finite element results: The most unfavorable working condition occurs at 345°, when the vertical force, eccentricity and lateral force act simultaneously, the maximum equivalent stress is 182.8MPa, and the maximum principal stress is -178.2MPa, both of which are lower than the safety limit of 200MPa. Therefore, the optimized fan-shaped opening design can maintain sufficient structural strength and safety under higher loads. Under each working condition, the maximum equivalent stress occurs at the minimum width of the spoke plate.

[0063] By optimizing the hole plan, hole sector and strength calculation, the semi-spoke force measuring track wheel design of the present invention greatly improves the sensitivity of the strain signal while ensuring the structural strength. The optimized track wheel can not only provide accurate measurement data under the action of vertical and lateral forces, but also withstand high loads under complex working conditions, and is suitable for various research scenarios such as railway vehicle dynamics tests.

[0064] In this embodiment, the test strain gauge arrangement and bridge circuit design are as follows:

[0065] In the present invention, multiple strain gauges are evenly arranged at key positions of the rail wheel, and these strain gauges are connected into a bridge circuit to measure the changes in wheel-rail forces in different directions. The principle of strain gauge arrangement is based on the results of finite element analysis to ensure that sufficient strain signals can be captured without increasing stress concentration.

[0066] Vertical force measurement bridge: The strain gauges are arranged at the inflection points of the wheel spokes. These locations have obvious strain responses and can capture the strain changes under the action of vertical forces. The strain gauges are connected through a full-bridge circuit to ensure the accuracy of signal acquisition.

[0067] Transverse force measurement bridge: strain gauges are arranged at the ends of the spokes and the straight plates. These areas have high sensitivity under the action of transverse force. Through the specific bridge design, the interference of vertical force on the transverse force measurement can be eliminated, ensuring that the output signal can accurately reflect the change of transverse force.

[0068] Figure 3 The layout of the strain gauges and the connection method of the bridge circuit are shown. The vertical force strain gauge is located at the inflection point to reduce the mutual interference between the lateral force and vertical force output signals; the lateral force strain gauge is located at the end of the spoke plate to enhance the signal sensitivity when measuring lateral force.

[0069] In this embodiment, the vertical force is solved as follows:

[0070] Principle of vertical force calculation: Through the output signal of the bridge circuit, the strain distribution under the unit vertical force can be calculated, and the actual vertical force under the external force can be further calculated. The calculation formula of the vertical force is as follows:

[0071] 1. Bridge output of unit vertical force:

[0072] When a unit vertical force (1kN) acts on the bridge, Figure 4 As shown, the signal output by the bridge circuit is:

[0073]

[0074] Through formula (1), the strain output of unit vertical force in each direction can be obtained.

[0075] 2. Correction of vertical force bridge output:

[0076] By correcting the phase angle, the output of the vertical force bridge is:

[0077]

[0078] This correction step is used to eliminate the error caused by phase angle changes.

[0079] 3. Calculation of vertical force under external load:

[0080] Under the action of Q(t), the vertical force bridge output is:

[0081] q1(θ)=Sq(θ)·Q(t) (3)

[0082] q2(θ)=Cq(θ)·Q(t) (4)

[0083] According to the measured bridge output signal, the vertical force measured in the test can be calculated by the following formula:

[0084]

[0085] Among them, Q cal (t) represents the vertical force measured in the test, q1(θ) and q2(θ) represent the output signals of the vertical force bridge under the actual vertical force Q(t), Sq(θ) represents the output signal of the bridge under the unit vertical force, Cq(θ) represents the output signal of the vertical force bridge after correcting the phase angle, and ε(θ) represents the strain distribution under the unit vertical force.

[0086] In this embodiment, the lateral force is solved as follows:

[0087] Principle of lateral force calculation: The calculation of lateral force involves the superposition and correction of bridge output signals to ensure that the signal interference between lateral force and vertical force is minimized. The key to lateral force calculation is to capture the strain signal under the action of lateral force through strain gauge arrangement and bridge design, and make corrections to obtain accurate lateral force values.

[0088] 1. Bridge output per unit lateral force:

[0089] When a unit lateral force (1kN) is applied, the output signal of the bridge circuit is:

[0090] Syy(θ)=[ε yA (θ)-ε yB (θ)+ε yB (θ+π)-ε yA (θ+π)] (6)

[0091]

[0092] Among them, Syy(θ) and Cyy(θ) both represent the output signal of the bridge circuit under the unit lateral force, ε yA (θ) and ε yB (θ) represents the strain distribution of the inner and outer surfaces under the unit lateral force, such as Figure 5 As shown in (a).

[0093] 2. Correction under eccentricity: In the actual measurement process, due to the eccentricity, the vertical force will also be accompanied by a certain bending moment effect, so it is necessary to correct the bending moment effect:

[0094] Syy(θ)=[ε yA (θ)-ε yB (θ)+ε yB (θ+π)-ε yA (θ+π)] (8)

[0095]

[0096] Among them, Sye(θ) and Cye(θ) both represent the output signal of the bridge under the action of unit bending moment (vertical force and eccentricity), ε ZA (θ) and ε ZB (θ) represents the strain distribution of the inner and outer surfaces under unit bending moment, such as Figure 5 (b).

[0097] 3. Calculation of lateral force:

[0098] Under the action of external loads Y(t) and Q(t), the lateral force bridge output is:

[0099] y1(θ)=Syy(θ)·Y(t)+Sye(θ)·Q(t)E(t) (10)

[0100] y2(θ)=Cyy(θ)·Y(t)+Cye(θ)·Q(t)E(t) (11)

[0101] Where E(t) represents the eccentricity of the vertical force action point, and y1(θ) and y2(θ) represent the signals measured by the bridge at different angles.

[0102] According to the bridge output results, the actual calculation formula for the lateral force is:

[0103]

[0104] Among them, Y cal_1 (t) represents the lateral force measured in the test, Y(t) and Q(t) represent the actual lateral force and vertical force, respectively.

[0105] In this embodiment, the main difference between the force measurement method in the standard GB / T5599 and the innovative method of the present invention is that the traditional force measurement method mostly adopts a phase-free solution method, ignoring the change of the phase angle of the wheel-rail contact point, resulting in a large measurement error. In the traditional method in the standard, the strain gauge arrangement is similar to that of the present invention, and the bridge road for measuring point arrangement is shown in FIG. Figure 6(Appendix C of GB / T5599), but the phase change of the wheel-rail contact point is not considered in the solution process. The calculation process is as follows:

[0106] Vertical force solution:

[0107] Bridge output under unit vertical force:

[0108]

[0109] Among them, ε(θ) represents the circumferential strain distribution of the neutral axis at the patch position under the action of unit vertical force;

[0110] Therefore, under the action of Q(t), the output result of the vertical force bridge circuit is:

[0111] q1G(θ)=Sq G (θ)·Q(t) (16)

[0112] q2G(θ)=Cq G (θ)·Q(t) (17)

[0113] According to the output results of the bridge circuit, the vertical force measured in the test is:

[0114]

[0115] In this embodiment, the lateral force is solved as follows:

[0116] Bridge output under unit lateral force + vertical force:

[0117]

[0118]

[0119] Among them, ε y and ε z are the strain distribution under unit transverse and bending moment, respectively.

[0120] Therefore, under the action of external loads Y(t) and Q(t), the lateral force bridge output is:

[0121] y 1G (θ)=Syy_G(θ)·Y(t)+Sye_G(θ)·Q(t)E(t) (23)

[0122] y 2G (θ)=Cyy_G(θ)·Y(t)+Cye_G(θ)·Q(t)E(t) (24)

[0123] According to the bridge circuit output results, the lateral force measured in the test is:

[0124]

[0125] In this embodiment, the rail wheel-rail force calculation method of the present invention is compared with the existing wheel-rail force measurement method in the GB / T5599 specification through a precisely designed bridge output system. It mainly includes the comparison of bridge output results under unit load and random load. This section analyzes in detail the performance of the two methods under different working conditions, especially the accuracy, error range and measurement sensitivity of the bridge output.

[0126] In this embodiment, the output results of the bridge circuit under unit load are compared:

[0127] The bridge output result of the present invention, the measured wheel-rail force in the figure is calculated by equation (5), equation (13), equation (18) and equation (26), the strain unit is με, and the force unit is kN.

[0128] 1. According to the design of the present invention, the bridge output of vertical force and lateral force is optimized to provide more accurate measurement data. In the test design, a unit vertical force Q = 1kN and a unit lateral force Y = 1kN were applied respectively, with an eccentricity of 1mm. Figure 7 It can be seen that Figure 7 (a) is the vertical force in this test, Figure 7 (b) is the standard vertical force (continuous measurement), Figure 7 (c) is the lateral force of this test, Figure 7 (d) is the standard lateral force, and the bridge output results are as follows:

[0129] Vertical force bridge output: When a unit vertical force of 1kN is applied, the bridge output signal fluctuates slightly, and the absolute value of the signal output is close to the horizontal line, indicating that this method can accurately reflect the change of vertical force. Calculated by the correction formula, the fluctuation amplitude of the bridge output signal is between -5% and 2.5%, proving that the accuracy of the present invention in vertical force measurement is very high.

[0130] Transverse force bridge output: Under the action of 1kN unit transverse force, the bridge output signal reflects the change of the transverse force. The absolute value of the signal output is also close to the horizontal line, and the fluctuation range is between -2% and 1.2%. Although the output signal intensity of the transverse force is relatively small, it still maintains a high measurement accuracy.

[0131] 2. The bridge output results in GB / T5599 specification:

[0132] The bridge design in the specification is relatively simple, and the phase angle information of the wheel-rail contact point is not considered in the calculation, so the output accuracy under unit load is lower than that of the present invention. By applying the same unit load, the bridge output results of the specification method are as follows:

[0133] Vertical force bridge output: When the standard method applies a 1kN vertical force, the bridge output signal fluctuates greatly, with a fluctuation range of -29% to 3.3%. Although the standard method can roughly reflect the change of vertical force, due to the neglect of phase angle information, the bridge signal has a large deviation and the measurement error is large, especially when the vertical force changes rapidly, the error is more obvious.

[0134] Transverse force bridge output: The lateral force bridge output signal and fluctuation amplitude are slightly larger than those of the method of the present invention.

[0135] Comparison summary under unit load:

[0136] It can be seen from the test data that the output of the bridge circuit of the present invention shows more stable and accurate results under unit load. The output signal error of the vertical force is only -5% to 2.5%, which is much lower than the -29% to 3.3% of the standard method. At the same time, the error of the lateral force is controlled at -2% to 1.2%, showing higher accuracy, but the output signal is weaker than the method given in the standard. After comprehensive consideration, the vertical force adopts this test bridge circuit, and the lateral force adopts the standard bridge circuit.

[0137] In this example, the output results of the bridge circuit under random load are compared:

[0138] During the test, the loads borne by the rail wheels and wheels in the test vary randomly. Therefore, the comparison of the bridge output results under random loads is of great significance for evaluating the reliability and stability of the measurement method. To this end, the bridge output results of the present invention and those in the GB / T5599 specification are compared respectively.

[0139] 1. The output result of the bridge circuit of the present invention

[0140] Under the action of random load, the bridge output design of the present invention takes into account the phase angle information and corrects the vertical force and the lateral force respectively. Therefore, the signal output by the bridge is more stable and has a smaller error.

[0141] Random load action without eccentricity:

[0142] Under the action of random load without eccentricity, assuming that the error standard deviation of the bridge output signal is 1με, the test results are as follows Figure 8 As shown in the figure, Figure 8 (a) is the vertical force in this test, Figure 8 (b) is the standard vertical force (continuous measurement), Figure 8 (c) is the lateral force of this test, Figure 8 (d) is the standard lateral force. The data show that the output signal of the bridge circuit of the present invention maintains a high stability under random loads, such as Fig. 9 As shown in the figure, Fig. 9 (a) is the vertical force in this test, Fig. 9 (b) is the standard vertical force (continuous measurement), Fig. 9 (c) is the lateral force of this test, Fig. 9 (d) is the standard lateral force. Since the bridge design takes into account the arrangement of strain gauges at different angles and phase angle correction, the measurement error is controlled within -4% to 3% compared with the standard method. Especially when the random load changes frequently, the signal output is still accurate.

[0143] Random load with eccentricity:

[0144] like Fig.10 As shown in the figure, in the case of eccentricity (eccentricity is 7mm), the test shows that the eccentricity has little effect on the vertical force, and the bridge output still maintains high accuracy. The eccentricity has a relatively large effect on the lateral force, about 3kN, but after the bridge is corrected, the error is still small and the overall output result is stable.

[0145] 2. Bridge output results in GB / T5599 specification

[0146] Compared with the present invention, the bridge design in the specification fails to effectively cope with the influence of random load and eccentricity, especially when the load changes rapidly, the error of signal output is large.

[0147] Under the action of random load with or without eccentricity, the output signal of the vertical force bridge of the standard method fluctuates greatly, while the output signal of the lateral force bridge fluctuates less, which is close to the method of the present invention. Fig. 9 As shown in the figure, since the standard method does not take phase angle correction into account, especially when the strain gauge arrangement is not reasonable, the accuracy of vertical force measurement is significantly reduced, resulting in large signal deviation.

[0148] 3. Comparison summary under random load

[0149] From the comparison results under random loads, it can be seen that the bridge output of the present invention still maintains high accuracy and stability under random loads (with and without eccentricity), and the error is controlled within a small range. In contrast, under the same working conditions, the vertical force bridge output signal error of the GB / T5599 standard method is large, and the eccentricity has a significant effect on the lateral force. Therefore, the measurement accuracy of the present invention under complex working conditions is significantly better than that of the standard method.

[0150] The rail wheel-rail force calculation method of the present invention shows more stable and accurate measurement results under both unit load and random load by optimizing the bridge design and phase angle correction. Compared with the traditional method in the GB / T5599 specification, the bridge output of the present invention has lower error in vertical force measurement, especially under random load and eccentricity conditions, and still maintains high accuracy. Therefore, the calculation method of the present invention has the advantage of high precision in the experimental measurement of wheel-rail force and can provide more reliable mechanical data.

[0151] The technical effect of the present invention is mainly reflected in the fact that the accuracy, stability and reliability of wheel-rail force measurement are significantly improved through the optimized track wheel design, the phase angle-based solution method and the improvement of the bridge structure. The following is a description of the specific effects of the present invention, and a quantitative analysis is performed in combination with the technical solution:

[0152] 1. Improved measurement accuracy

[0153] The present invention solves the measurement error problem caused by unreasonable strain gauge position and neglect of phase angle information in the traditional wheel-rail force measurement method by optimizing the arrangement of strain gauges and bridge design. Under the action of random loads, the measurement results of the present invention are more accurate and stable. The random loads with and without eccentricity were tested in the experiment.

[0154] Vertical force measurement accuracy: The strain gauge of the vertical force is arranged at the inflection point, so that the bridge can accurately reflect the change of the vertical force. Compared with the traditional measurement method, the present invention effectively reduces the random error through strain gauge optimization and phase angle correction. The test shows that under the action of random loads, the fluctuation range of the vertical force measurement error is reduced to -4% to 3%, which is much smaller than the -40% to -50% of the traditional method in the GB / T5599 specification, indicating that the present invention can still maintain high-precision measurement under the action of random loads.

[0155] Transverse force measurement accuracy: The transverse force strain gauge is arranged at the end of the spoke plate. This position can maximize the capture of the strain signal of the lateral force and reduce the vertical force interference. At the same time, under the condition of eccentricity, although the fluctuation of the lateral force increases slightly, after the phase angle correction, the lateral force measurement error fluctuation of the present invention is controlled within 5%. This accuracy improvement is particularly important under complex working conditions, ensuring the continuous measurement and high-precision calculation of the wheel-rail force during the test process, and providing high-precision wheel-rail force data under different working conditions.

[0156] 2. Simplify the test process and reduce time cost

[0157] The traditional wheel-rail force measurement method requires installing multiple strain gauges on the axle or wheel rim and performing repeated calibration and debugging, which not only increases the complexity of the test process but also increases the time cost.

[0158] Simplified test process: The present invention simplifies the installation process of strain gauges by designing a rail wheel force measuring device. In the traditional method, the strain gauges need to be repeatedly installed for wheel-rail force measurement of different vehicle models. However, the rail wheel equipment of the present invention can complete the installation and debugging of the strain gauges at one time through a unified design, without the need for repeated debugging for different vehicle models. The test preparation time is reduced by more than 40%.

[0159] Shortened commissioning time: Due to the optimization of the bridge structure and the reasonable layout of the strain gauges, the multiple calibration work during the test process was reduced, and the total test time was reduced by about 30%. This simplification significantly reduced the preparation and execution time of large tests and improved the test efficiency.

[0160] 3. Improvement of measurement sensitivity

[0161] The invention significantly improves the sensitivity of the measuring system by optimizing the design of the openings of the spoke plate, and in particular, the strain output of the vertical force is significantly amplified.

[0162] Optimization effect of the hole opening scheme: Experiments have shown that by optimizing the traditional solid structure of the spoke plate to a fan-shaped hole design, the strain signal under the vertical force has increased by about 2.5 times. Before the hole opening, the radial strain when the vertical force Q = 10kN is only 3.1με, while after the fan-shaped hole opening, the radial strain is increased to 7.7με. This shows that the present invention can significantly amplify the strain signal and improve the measurement sensitivity through the hole design.

[0163] The optimized sector-shaped opening balances strength and sensitivity: Under the premise of maintaining structural strength, the optimized sector-shaped opening design can effectively reduce the stress concentration phenomenon under the action of lateral force. Compared with circular openings, the maximum radial strain of the sector-shaped openings is increased by about 10%, while the maximum stress is reduced to 15MPa, which is lower than the safety limit (18MPa), ensuring the structural safety under complex loads.

[0164] 4. Enhanced anti-interference ability and stability

[0165] Since the traditional measurement method does not consider the phase angle change of the wheel-rail contact point, the measurement process is easily affected by external interference, especially when the wheel is running at high speed during the test, the stability of the measurement signal is poor. The present invention significantly improves the anti-interference ability by introducing the phase angle correction technology.

[0166] Effect of phase angle correction: Under different working conditions, especially high-speed operation and random load, the present invention can reduce the fluctuation of strain signal through phase angle correction algorithm. Tests show that the signal fluctuation amplitude of the traditional method under random load reaches -40% to -50%, while the fluctuation amplitude of the present invention is reduced to -4% to 3% after phase angle correction, indicating that it has better anti-interference ability under complex working conditions.

[0167] Measurement signal stability: Under complex loads, the measurement signals of vertical force and lateral force are more stable. Test results show that the signal fluctuation range of lateral force is only 5%, indicating that the present invention can provide more reliable and consistent measurement data.

[0168] 5. Reduce equipment service life and maintenance costs

[0169] Traditional wheel-rail force measurement methods rely on a large number of strain gauges installed on dynamic components such as axles and wheel rims, which are easily affected by wear, vibration and external environment, resulting in high equipment maintenance costs and short service life.

[0170] Optimization of strain gauge arrangement: The present invention avoids damage to the strain gauge caused by high-speed movement by arranging the strain gauge on the rail wheel equipment instead of directly installing it on the wheel and axle. The fixing device of the rail wheel can maintain the stability of the equipment during the measurement process and reduce the loss of the measuring equipment caused by the dynamic changes of the vehicle.

[0171] Reduced maintenance frequency: Due to the reasonable arrangement of the strain gauges of the present invention and the small dynamic load of the equipment, the loss of the equipment is reduced, the service life of the equipment is extended, and the maintenance frequency is reduced by more than 30%. At the same time, the equipment maintenance cost is reduced by about 25%.

[0172] In summary, the present invention significantly improves the accuracy, sensitivity and stability of wheel-rail force measurement by optimizing the track wheel force measuring device, bridge design, phase angle correction and strain gauge arrangement, and provides significant improvements in test process, maintenance cost, equipment service life, etc. Combined with the above quantitative data, it can be seen that compared with the traditional method, the measurement error of the present invention is significantly reduced, the test process is simplified by 40%, and the maintenance cost is reduced by 25%. These effects fully demonstrate the significant advantages of the present invention in the field of wheel-rail force measurement.

[0173] In summary, the highlights of the present invention are as follows:

[0174] 1. High-precision wheel-rail force measurement. By mounting strain gauges on the rail wheel equipment and combining phase angle solution technology, the present invention can accurately measure the vertical force and lateral force at the wheel-rail contact point, especially under complex working conditions such as random loads and eccentricity, and can provide stable and reliable data output.

[0175] 2. Application of phase angle information. Different from the traditional method without phase angle solution, the present invention introduces phase angle information in the measurement process, so that the measured wheel-rail force can more truly reflect the actual situation of the wheel-rail contact point, reduce the error in the signal transmission process, and improve the measurement accuracy.

[0176] 3. Simplified test process. The traditional wheel-rail force measurement method requires strain gauges to be installed at key locations such as axles and wheel rims, and the measurement of different vehicle models requires repeated installation and debugging. The design of the rail wheel device of the present invention simplifies this process. Only one-time installation of the rail wheel equipment is required to perform continuous measurement, which greatly shortens the test preparation time.

[0177] 4. Improved sensitivity. Compared with the traditional spoke-type wheels, the rail wheel equipment of the present invention optimizes the arrangement of strain gauges and the shape design of the spoke plates, making it more sensitive to the strain response to external excitation, and can provide greater strain output under the action of vertical force and lateral force, thereby improving the measurement accuracy.

[0178] The present invention improves and optimizes many technical defects in the existing wheel-rail force calculation method through innovative design and technical means, and can effectively solve the following problems in the current wheel-rail force calculation method:

[0179] 1. The test process is cumbersome. The commonly used wheel-rail force measurement method requires the installation of multiple strain gauges on the axle, wheel rim or other key parts, which not only requires the test personnel to have high technical capabilities, but also increases the complexity and time-consuming test preparation. Especially in different vehicle models or different test environments, the strain gauges need to be reinstalled and calibrated before each test, which significantly increases the cost and time investment of the test.

[0180] The present invention avoids the complicated process of repeatedly installing strain gauges on different vehicle models by designing a rail wheel force measuring device. The rail wheel equipment can be installed on the track at one time, and the continuous measurement of wheel-rail force can be achieved by presetting the strain gauge position, thereby simplifying the test process, reducing the installation time and the workload of equipment debugging, and improving the test efficiency.

[0181] 2. Phase angle information is ignored. Most existing measurement methods ignore the phase angle change of the wheel-rail contact point during wheel rotation, and only rely on strain gauges to measure amplitude signals to infer wheel-rail force. This method is prone to errors in dynamic conditions, especially when the vehicle is running at high speed. The wheel-rail force is a dynamically changing quantity, and its direction and magnitude constantly change during wheel rotation. If these phase angle information are ignored, the measured wheel-rail force will not accurately reflect the actual mechanical properties, resulting in distorted measurement results.

[0182] The present invention adopts a solution method based on phase angle, which incorporates the phase angle change of the wheel-rail contact point into the calculation process, and can more accurately reflect the dynamic changes of the wheel-rail force. By introducing phase angle information, the present invention can better capture the directional changes of the wheel-rail force, greatly improving the accuracy of the measurement, especially under complex working conditions such as random loads in the test, this improvement significantly reduces the error.

[0183] 3. Low measurement sensitivity. In the prior art, the spoke-type wheel design used in the wheel-rail force measurement method has certain weight reduction and load-bearing advantages in structure, but it may lead to a small strain signal during the stress transfer process, thus affecting the measurement accuracy. In addition, the structural characteristics of the spoke-type wheel also limit its measurement sensitivity under the action of wheel-rail force.

[0184] The present invention optimizes the rail wheel equipment, especially improves the opening shape of the wheel spoke plate and the arrangement position of the strain gauge, so that the equipment shows higher sensitivity under the action of vertical force and lateral force. The test shows that the design of fan-shaped openings greatly increases the output of strain signals, and can capture greater strain changes under the action of various forces, making the measurement results more accurate and stable, meeting the high sensitivity requirements in wheel-rail force measurement.

[0185] 4. Insufficient measurement accuracy. Existing measurement methods usually ignore the mechanical complexity of the dynamic process of wheel-rail force, especially the large differences in the measurement accuracy of forces in different directions. The traditional wheel-rail force measurement method is relatively accurate in measuring lateral forces, but in the measurement of vertical forces, due to its low sensitivity, it is often difficult to accurately reflect the actual force conditions when the wheel and rail are in contact. In addition, due to the deviation of the system measurement device in the force transmission path in different directions, there may be a large difference between the calculated results and the actual values.

[0186] The present invention not only improves the sensitivity of the strain gauge, but also significantly improves the accuracy of wheel-rail force calculation through the phase angle solution algorithm, especially in the measurement of vertical force. Through the continuous measurement and calculation of forces in different directions, the present invention can better reflect the actual changes in wheel-rail force during vehicle operation, significantly improve the accuracy of mechanical data, and reduce errors caused by device structure problems.

[0187] 5. Equipment maintenance is difficult and easy to damage. In the traditional wheel-rail force measurement method, strain gauges are often directly installed on components such as axles or rims. During the test, they are in high-speed motion and high-pressure environment for a long time, and are easily affected by external factors such as vibration, impact and wear, resulting in a short equipment life and high maintenance costs. Damage to the strain gauge not only affects the accuracy of the measurement, but also causes test interruption or data loss.

[0188] The rail wheel force measuring device of the present invention is designed on the rail wheel rather than the wheel itself, avoiding the influence of the axle and wheel on the measuring device during high-speed movement. By arranging the strain gauge in the rail wheel device, the risk of equipment damage is reduced, and the durability and reliability of the device are improved. In addition, the device of the present invention is easy to install, convenient for subsequent maintenance and updating, and greatly reduces the maintenance cost of the equipment and the risk of test interruption.

[0189] 6. Data processing lags, making continuous measurement difficult. The current wheel-rail force measurement system has limited efficiency in data collection and processing, especially when the wheels are running at high speeds. Due to the large amount of data and rapid changes, traditional measurement systems are difficult to achieve continuous measurement of wheel-rail forces, which may cause data lag and distortion, affecting the test results.

[0190] The present invention can realize real-time and continuous measurement of wheel-rail force by simplifying the data collection process and optimizing the solution algorithm. In particular, during the high-speed operation of the rail wheel, the force measuring device of the present invention can quickly respond to the mechanical changes of the wheel and rail, ensure the real-time and accuracy of the data, and meet the needs of continuous force measurement and solution of wheel-rail force in the test.

Claims

1. A method for continuous force measurement and solution of a spoke type rail wheel, characterized in that: The spoke type rail wheel continuous force measurement and solution method is applied to a rail wheel force measuring device, comprising the following steps: A plurality of strain gauges connected into a bridge circuit are evenly arranged on the spoke type rail wheel; Through the output signal of the bridge circuit, the strain distribution under the unit vertical force is calculated, and the actual vertical force under the external force is obtained; By superimposing and correcting the output signals of the bridge circuit, the lateral force is obtained, thus completing the continuous force measurement and solution of the spoke-type rail wheel.

2. The method for continuous force measurement and solution of a spoke type rail wheel according to claim 1, characterized in that: The method of evenly arranging a plurality of strain gauges connected to form a bridge circuit on the spoke-type rail wheel is as follows: Vertical force measurement bridge: multiple strain gauges are arranged at the inflection points of the spokes to obtain the strain changes under the vertical force, where the strain gauges are connected through a full bridge circuit; Transverse force measurement bridge: multiple strain gauges are arranged at the ends of the spoke plates and the straight plates to eliminate the interference of vertical force on the lateral force measurement. The expression of the vertical force measured in the test is as follows: q1(θ)=Sq(θ)·Q(t) q2(θ)=Cq(θ)·Q(t) Among them, Q cal (t) represents the vertical force measured in the test, q1(θ) and q2(θ) represent the output signals of the vertical force bridge under the actual vertical force Q(t), Sq(θ) represents the output signal of the bridge when a unit vertical force acts, Cq(θ) represents the output signal of the vertical force bridge after correcting the phase angle, θ represents the rotation angle of the track wheel, ε(θ), ε(θ+π), and Both represent the strain distribution of measuring points arranged at angles on the track wheel under the action of unit vertical force.

3. The method for continuous force measurement and solution of a spoke type rail wheel according to claim 2, characterized in that: The expression of the lateral force is as follows: y1(θ)=Syy(θ)·Y(t)+Sye(θ)·Q(t)E(t) y2(θ)=Cyy(θ)·Y(t)+Cye(θ)·Q(t)E(t) Sye(θ)=[ε ZA (i)-e ZB (i)+e ZB (θ+π)-e ZA (θ+π)] Syy(θ)=[ε yA (i)-e yB (i)+e yB (θ+π)-e yA (θ+π)] Among them, Y cal (t) represents the lateral force measured in the test, Syy(θ) and Cyy(θ) represent the output signal of the bridge under the unit lateral force, y1(θ) and y2(θ) represent the output signal of the bridge under the external load, Y(t) represents the actual lateral force, E(t) represents the eccentricity of the vertical force point, Sye(θ) and Cye(θ) represent the output signal of the bridge under the unit vertical force and eccentricity, ε ZA (θ) and ε ZB (θ) represents the strain distribution of the inner and outer surfaces under the action of unit vertical force and eccentricity, ε yA (θ) and ε yB (θ) represents the strain distribution on the inner and outer surfaces under unit lateral force.

4. The method for continuous force measurement and solution of spoke type rail wheel according to claim 1, characterized in that: The rail wheel force measuring device comprises a rail wheel and a strain gauge; The track wheel is installed between the wheel axle and the bearing seat through a bearing, and the strain gauge is arranged on the track wheel.

5. The method for continuous force measurement and solution of spoke type rail wheel according to claim 4, characterized in that: The spoke plate of the track wheel adopts a half-spoke design, and is provided with openings on the spoke plate; The strain gauge is arranged at the inflection point of the spoke plate; the strain gauge is arranged at the end of the spoke plate and the straight plate.

6. The method for continuous force measurement and solution of a spoke type rail wheel according to claim 5, characterized in that: The openings on the spoke plate are fan-shaped.

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