Automobile steering NVH test system and test method

Abstract

The application discloses a vehicle steering NVH test system and a test method. The anechoic chamber and the load simulation assembly are separated by sound insulation, and a through-wall connecting rod is used to transfer the load, so that the measured steering system independently operates in an ultrasonic environment with static background noise not higher than 30 decibels, and the pollution of the mechanical operation, friction contact and motor electromagnetic noise of the load simulation device itself to the test signal is isolated. The output end of the load simulation assembly is directly and rigidly connected with a tire wheel core, so that the vertical load is vertically and downwardly transmitted along the wheel core axis, the ground footprint pressure of the tire and the test pavement unit is uniformly distributed in a central symmetry, compared with the traditional scheme in which the loading point is offset to the edge of the hub or the suspension swing arm connecting point, the tire tread eccentric wear, the ground pressure concentration and the ground footprint distortion caused by eccentric loading are avoided, and the friction characteristics between the tire and the pavement, the lateral force response and the return torque generation mechanism are consistent with the actual vehicle state.

Description

Technical Field

[0001] This invention relates to the field of automotive steering system testing technology, specifically to an automotive steering NVH testing system and testing method. Background Technology

[0002] The automotive steering system is the actuator connecting the driver and the vehicle's trajectory, and its NVH performance directly affects the overall comfort and perceived quality of the vehicle. With the widespread application of electric power steering and steer-by-wire systems, steering system noises, such as motor whine, gear meshing impact noise, and bearing vibration, have become frequent quality challenges during vehicle development. Therefore, in the bench verification phase of the steering system, constructing a test environment that can realistically replicate real-vehicle load conditions and accurately extract its inherent NVH characteristics is of great significance.

[0003] Existing NVH bench testing solutions for steering systems typically place the steering system assembly and load simulation device in the same physical space. To load the steering rack, the load simulation device often employs servo motors, hydraulic actuators, or mechanical friction discs, which themselves generate significant electromagnetic noise, mechanical vibration, and airflow disturbances during operation. These interference signals highly overlap with the radiated noise and structural vibration of the steering system under test in both the time and frequency domains, resulting in insufficient signal-to-noise ratio in the test system. Weak abnormal noise signals are easily drowned out by background noise, making it difficult to accurately locate and extract the characteristics of the abnormal noise source.

[0004] On the other hand, existing load simulation methods mostly use rigid force loading or rotating inertia disks to simulate steering resistance, failing to realistically reproduce dynamic load characteristics such as the dynamic migration of the tire contact patch center with the turning angle and the change in friction characteristics of the contact interface with the road surface material during vehicle steering. This deficiency leads to a deviation in mechanical characteristics between bench conditions and real vehicle conditions, and some abnormal noise phenomena are only exposed in actual road tests, seriously affecting development efficiency and problem reproduction rate. Summary of the Invention

[0005] To address the technical problems of high background noise interference and distortion of dynamic characteristics in load simulation during traditional steering system NVH testing, this invention proposes an automotive steering NVH testing system and method. It isolates the quiet chamber from the load simulation component, transmits the load through a through-wall connecting rod, and adopts a wheel center vertical loading and eccentricity rotation drive structure in the load simulation component to achieve continuous dynamic adjustment of the steering load application point with the steering angle.

[0006] The technical solution adopted by this invention is as follows: A vehicle steering NVH testing system includes a soundproof chamber, a load simulation component, a connecting rod, and a data processing system, wherein: the soundproof chamber is used to house the steering system under test; the load simulation component is located outside the soundproof chamber and is used to simulate the load acting on the steering system under test when the vehicle is in motion; the connecting rod passes through the wall of the soundproof chamber and connects the output end of the load simulation component to the load input end of the steering system under test located inside the soundproof chamber; the data processing system includes a torque angle sensor, a load force sensor, a noise sensor, a vibration sensor, a synchronous acquisition module, and a data analysis module, wherein the torque angle sensor is used to collect torque angle data. The system inputs torque and angle signals. The load force sensor is used to collect the load force signal on the load simulation component. The noise sensor is used to collect the noise signal in the quiet room. The vibration sensor is used to collect the vibration signal in the quiet room. The synchronous acquisition module is used to synchronously acquire and record the signals output by the torque and angle sensor, load force sensor, noise sensor, and vibration sensor. The data analysis module performs order analysis based on the signals recorded by the synchronous acquisition module. The order analysis uses the speed pulse signal converted from the motor speed signal of the steering system under test as a reference and performs equal-angle resampling on the time-domain signals of the noise signal and vibration signal.

[0007] Optionally, the load simulation component includes an axle module and a loading component. The axle module includes a tire for simulating a wheel and a test surface unit located below the tire. The tire is perpendicular to the test surface unit. The loading component applies a vertically downward loading force to the tire. One end of the connecting rod is connected to the tire or the loading component, and the other end of the connecting rod is connected to the load input terminal of the steering system under test.

[0008] Optionally, the surface of the test pavement unit is covered with a replaceable friction material.

[0009] Optionally, the loading assembly includes a bracket, a lead screw, a nut, a pressing block, a sleeve, a spring, a connecting block, and a handwheel. The nut is fixedly installed on the bracket, the lead screw is threadedly engaged with the nut, the handwheel is drively connected to the lead screw, the sleeve is rotatably connected to the bracket via a bearing, and the sleeve has an axial guide space inside. The pressing block is disposed within the guide space of the sleeve and is connected to the lower end of the lead screw. The pressing block is slidably engaged with the inner wall of the sleeve. The spring is sleeved between the pressing block and the connecting block. One end of the connecting block is rigidly connected to the sleeve, and the other end of the connecting block is connected to the wheel center of the tire. The side of the connecting block facing away from the tire has a pin hinged to a connecting rod, and the axis of the pin and the rotation axis of the sleeve have an eccentricity in the horizontal plane.

[0010] Optionally, the data processing system further includes a signal acquisition module, which is used to acquire the internal electrical signals of the steering system controller under test. The synchronous acquisition module synchronously acquires the internal electrical signals and signals from the torque angle sensor, load force sensor, noise sensor and vibration sensor to generate a multi-source synchronous signal. The internal electrical signals include at least one of motor speed signal and current signal.

[0011] Optionally, the data analysis module performs at least one of the following based on the multi-source synchronization signal: fast Fourier transform spectrum analysis, order analysis, sound pressure level calculation, psychoacoustic parameter calculation, and transmission path analysis.

[0012] Optionally, the inner wall of the quilted room is lined with sound-absorbing material, and the static background noise of the quilted room is no more than 30 decibels.

[0013] This invention also discloses a test method using the automotive steering NVH test system described above, comprising the following steps:

[0014] S1. Install the steering system to be tested onto the bench fixture in the quiet room;

[0015] S2. Connect the load simulation component located outside the soundproof room to the load input terminal of the steering system under test via a connecting rod passing through the wall of the soundproof room.

[0016] S3. Operate the load simulation component to apply a simulated load to the steering system under test, and dynamically adjust the load application point according to the steering angle;

[0017] S4. Perform steering operation at the steering input end of the steering system under test in a quiet room;

[0018] S5. The noise and vibration signals in the quiet room, the torque and angle signals at the steering input end, and the load force signals transmitted by the connecting rod are synchronously collected through the data processing system.

[0019] S6. The data analysis module performs order analysis on the synchronously acquired signals to diagnose the source of the abnormal noise.

[0020] Determining the source of the abnormal noise includes the following steps:

[0021] S61. Obtain the motor speed signal of the steering system under test, convert the motor speed signal into an analog speed pulse signal, and then generate a standard speed pulse signal based on the analog speed pulse signal.

[0022] S62. Using the standard rotational speed pulse signal as a reference, the time-domain vibration signal and the time-domain noise signal are resampled at equal angles to obtain the angular domain vibration signal and the angular domain noise signal. The angular domain vibration signal and the angular domain noise signal are then subjected to Fourier transform to generate a rotational speed-frequency spectrum.

[0023] S63. Extract the order slice related to the steering system under test from the speed-frequency spectrum, and determine the source of abnormal noise based on the spectral morphology of the order slice.

[0024] The beneficial effects of this invention are as follows: By separating the soundproof chamber and the load simulation component for sound insulation, and using a through-wall connecting rod to transfer the load, the steering system under test can operate independently in an ultra-quiet acoustic environment with a static background noise level not exceeding 30 decibels, thus isolating the test signal from the mechanical operation, friction contact, and electromagnetic noise of the load simulation device itself; by directly and rigidly connecting the output end of the loading component to the tire wheel center, the vertical load is transmitted vertically downward along the wheel center axis, ensuring that the ground imprint pressure between the tire and the test road surface unit is centrally symmetrically and uniformly distributed. Compared with the traditional solution that offsets the loading point to the wheel hub edge or suspension arm connection point, this avoids tire tread wear, ground pressure concentration, and ground imprint distortion caused by eccentric loading, making the friction characteristics, lateral force response, and self-centering torque generation mechanism between the tire and the road surface highly consistent with the actual vehicle condition. Meanwhile, this invention generates an analog speed pulse signal by converting the time-domain discrete motor speed signal acquired from the CAN bus into a two-step speed-pulse-speed conversion signal. Using this pulse signal as a reference, and combining it with order tracking technology, it performs equal-angle resampling. This enables high-precision angle-domain resampling of vibration and noise signals without the need for an additional speed sensor, effectively solving the problems of low update frequency and lack of equal-angle characteristics in CAN speed signals, which prevent direct use for order tracking. Through order slicing analysis, based on the differences in spectral morphology, it is possible to clearly and accurately distinguish whether the abnormal noise in the steering system originates from the electromagnetic excitation of the motor or the mechanical meshing of the gears, providing clear experimental basis and quantitative data support for subsequent targeted optimization design. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the automotive steering NVH testing system proposed in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the load simulation component proposed in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the sensor arrangement of the data processing system proposed in an embodiment of the present invention;

[0028] Figure 4 This is a flowchart of the data processing and analysis process proposed in an embodiment of the present invention;

[0029] Figure 5 This is a sequence slice analysis diagram proposed in an embodiment of the present invention.

[0030] The labels in the attached figures are as follows: 1. Silent chamber; 2. Tire; 3. Test road surface unit; 4. Bracket; 5. Lead screw; 6. Connecting rod; 7. Torque angle sensor; 8. Load force sensor; 9. Noise sensor; 10. Vibration sensor; 12. Nut; 13. Compression block; 14. Sleeve; 15. Spring; 16. Connecting block; 17. Bearing. Detailed Implementation

[0031] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0032] This embodiment discloses an automotive steering NVH testing system, including a soundproof chamber, a load simulation component, a connecting rod, and a data processing system.

[0033] The soundproof chamber is constructed as a five-sided (excluding floor) sealed soundproof space, with its inner walls lined with high-efficiency sound-absorbing materials (such as composite sound-absorbing wedges or porous sound-absorbing cotton) to create an ultra-low background acoustic environment. In this embodiment, after calibration, the static background noise of the soundproof chamber is no higher than 30 dB (A-weighted). The soundproof chamber provides a pure acoustic shield to accommodate the steering system under test (such as C-EPS, P-EPS, steer-by-wire systems, etc.) and its near-end fixtures, ensuring that the collected noise signals originate purely from the electromagnetic noise of the steering system's own motors, gear meshing noise, etc., greatly improving the signal-to-noise ratio and diagnostic accuracy of NVH testing. The soundproof chamber is equipped with a high-rigidity, modular mechanical bench and fixture system (not shown), which can quickly adapt to the installation and attitude adjustment of different models of steering systems. All adjustment operations are completed in a soundproof environment, ensuring the consistency of the test conditions.

[0034] The load simulation assembly, located outside the silent chamber, includes an axle module and a loading component. The axle module comprises a tire and a test surface unit. The tire simulates a real vehicle wheel. The test surface unit is fixed directly beneath the tire, its surface covered with replaceable friction material (e.g., asphalt or cement blocks) to simulate different road surface adhesion coefficients. The tire is installed perpendicularly to the test surface unit. The loading component applies a downward vertical load to the tire and includes a bracket, lead screw, nut, compression block, sleeve, spring, connecting block, and handwheel. The bracket is fixedly mounted on the ground or base, the nut is fixedly mounted on the bracket, the lead screw is threaded into the nut, and the lead screw is connected to the handwheel via a transmission mechanism (either directly or through a bevel gear). The sleeve is rotatably connected to the bracket via a bearing, allowing the sleeve to rotate relative to the bracket about a vertical axis. The sleeve has an axial guide space inside. The extrusion block is positioned within the guide space of the sleeve and connects to the lower end of the lead screw (it can abut or connect). The outer wall of the extrusion block and the inner wall of the sleeve are in sliding fit, allowing it to move only along the axial direction of the sleeve. The spring is sleeved between the extrusion block and the connecting block. The connecting block has a spring seat, and the two ends of the spring abut against the extrusion block and the spring seat respectively, used to transmit and buffer vertical loads. One end of the connecting block is rigidly connected to the sleeve (e.g., by welding or bolting), and the other end is connected to the wheel center of the tire (usually a fixed connection, such as through wheel hub bolts). The side of the connecting block facing away from the tire has a pin. One end of the connecting rod is hinged to the connecting block through the pin, with the hinge point being P. The projection of the hinge point P onto the horizontal plane has a non-zero eccentricity e between it and the rotation axis O of the sleeve. This ensures that the line of action of the axial tensile force F of the connecting rod always maintains a lever arm (length approximately e) with respect to the rotation center O. Therefore, the tensile force F can continuously generate an effective torque M (M≈F×e) to drive the sleeve 1 to rotate. In contrast, if the projection of hinge point P is directly below the rotation axis O (i.e., eccentricity e = 0), the line of action of the tension F of the connecting rod will pass through the rotation center O. At this point, the lever arm is zero, and no driving torque can be generated, causing the mechanism to fail at a dead point. Similarly, if the projection of hinge point P is located at a specific angle to the side of the rotation axis O, making the line of action of the tension F perpendicular to the line connecting OP, the lever arm is also zero, and the mechanism also fails. Therefore, intentionally setting and ensuring a non-zero eccentricity e, and ensuring that the mechanism avoids the aforementioned theoretical dead point position during its working stroke, is the core design of this invention for achieving reliable and continuous motion conversion. This design cleverly and efficiently converts the linear tension of the connecting rod into the rotational torque of the sleeve. The other end of the connecting rod passes through a sealed interface on the wall of the silent chamber and connects to the rack output end (load input end) of the steering system under test inside the silent chamber. The data acquisition system includes noise sensors and vibration sensors installed in a quiet room, torque and angle sensors installed at the steering wheel input end, load force sensors installed on the connecting rod, and a synchronous acquisition and processing unit for synchronously acquiring and analyzing the NVH performance of the steering system.

[0035] Turning the handwheel moves the lead screw downwards, pushing the compression block to compress the spring. The spring force is transmitted to the tire through the connecting block, pressing the tire vertically against the test surface unit to simulate the load of the entire vehicle. When the steering system under test is working, the connecting block is pulled or pushed via the connecting rod. Because the connecting block is rigidly connected to the sleeve, and the sleeve is rotatably connected to the bracket via a bearing, the horizontal force applied by the connecting rod causes the sleeve to drive the connecting block and the tire to rotate around the bearing axis. During this process, sliding friction and shear deformation occur between the vertically pressed tire and the test surface. This resistance is fed back to the steering system through the connecting rod, forming a steering load that conforms to the dynamic characteristics of a real vehicle. In the low-noise environment provided by the silent chamber, the data acquisition system simultaneously records steering torque, steering angle, tie rod force, noise, and vibration signals. Through analysis, the source of abnormal noise and NVH performance of the steering system can be accurately diagnosed.

[0036] The connecting rod is one or more extendable steering tie rods, which pass through the wall of the quilted chamber and have a special sealed interface to ensure sound insulation. The steering motion and resistance of the tires in the outdoor load simulation component are transmitted without damage to the rack output end of the steering system under test in the quilted chamber.

[0037] The data processing system includes a torque angle sensor, a load force sensor (rack force sensor), a noise sensor (such as a high-precision microphone), a vibration sensor (such as a triaxial accelerometer), a signal acquisition module, a synchronous acquisition module, and a data analysis module. The torque angle sensor is installed on the steering wheel input shaft of the steering system under test to acquire steering torque and angle signals with high precision, which is the direct basis for evaluating steering feel. The two load force sensors are connected in series on the connecting rods at the output ends of the left and right racks, respectively, to directly measure the tension / compression signals transmitted from the load simulation component to the steering rack.

[0038] Noise and vibration sensors are located in a soundproof chamber, close to critical components such as the steering motor, gearbox, and tubing. The noise sensors collect radiated noise; the vibration sensors (such as triaxial accelerometers) collect structural vibrations. Thanks to the ultra-low background noise of the soundproof chamber, these sensors can detect extremely faint abnormal noises and vibrations.

[0039] The signal acquisition module directly reads the internal signals of the electronic control unit (ECU) of the steering system under test, such as motor current, speed, and target torque, via CAN bus or Ethernet.

[0040] The synchronous acquisition module uses hardware clock synchronization technology to perform strictly synchronized time-aligned acquisition of all signals from the torque angle sensor, load force sensor, noise sensor, vibration sensor, and signal acquisition module (e.g., sampling rate ≥ 1 kHz, synchronization accuracy in the microsecond range). This ensures that all time-domain signals have a unified time reference, providing a unique and reliable data foundation for subsequent correlation analysis and causal relationship diagnosis (such as transmission path analysis).

[0041] The data analysis module runs on a professional software platform (such as Siemens Testlab, HEADacoustics Artemis, etc.) in the host computer. It receives multi-source synchronous signals uploaded by the synchronous acquisition module and performs at least one of the following: fast Fourier transform spectrum analysis, order analysis, sound pressure level calculation, psychoacoustic parameter calculation, and transmission path analysis.

[0042] Order analysis is the core method used in this invention to distinguish between motor whistling and gear meshing noise. Specifically, the order analysis uses the speed pulse signal converted from the motor speed signal of the steering system under test as a reference. It performs equal-angle resampling on the time-domain noise signal collected by the noise sensor and the time-domain vibration signal collected by the vibration sensor, converting the time-domain signal into an angular-domain signal, thereby establishing the correspondence between the noise / vibration signal and the rotation angle. The purpose of this equal-angle resampling is to eliminate the influence of speed fluctuations on signal analysis, ensuring that the frequency components in subsequent spectrum analysis accurately correspond to the rotation order of the motor. Since the motor speed signal directly obtained through the CAN bus is a discrete value in the time domain, its update frequency is low and it lacks equal-angle characteristics. If directly used for order tracking, it would lead to insufficient accuracy of the angular-domain resampling. Therefore, this embodiment uses a two-step conversion method to process the speed signal, as follows:

[0043] First, for the motor speed signal acquired from the CAN bus, the following two steps are performed using signal processing tools in a data processing software platform (such as Testlab, MATLAB, etc.): Step 1, RPM → Tacho Pulse, converting the continuous speed signal into an analog speed pulse signal, and setting the channel type of the generated channel to Tacho; Step 2, TachoPulse → RPM, converting the pulse signal back to the device's internal standard speed value as a reference for subsequent angle domain resampling. If the motor speed cannot be directly obtained, it can be calculated using the formula: Motor speed = Steering wheel speed × Total transmission ratio of the steering system.

[0044] Then, using the converted standard rotational speed pulse as a reference, the original time-domain vibration and noise signals are resampled at equal angles. The instantaneous rotational speed and instantaneous phase at each pulse moment are calculated using the rotational speed pulse signal, establishing a mapping relationship between the time domain and the angle domain. The time-domain signal is then resampled with a constant angle increment to obtain the angle-domain signal.

[0045] Next, an FFT transform is performed on the angular domain signal to generate a rotational speed-frequency color spectrum. On this spectrum, the diagonal lines emanating from the origin represent the order excitation synchronized with the rotational speed, and the vertical lines at fixed frequencies represent the structure's natural frequencies or resonance bands.

[0046] Finally, order slicing analysis is performed. In the software, order tracking mode is set, the speed range is selected, and self-power spectrum is chosen for both acoustic and vibration channels. A-weighting is applied to the acoustic channel. Within the order selection area, based on the number of motor pole pairs and slot-pole matching, relevant system orders are selected for slicing calculations (e.g., for an 8-pole motor, orders 8, 16, and 24 are selected for analyzing electromagnetic scheme optimization; for mechanical related optimizations, lower orders and transmission ratio-related orders are analyzed). After extracting the high-order amplitude slice curves, the noise or vibration spectrum at that order can be obtained. Based on this, the source of abnormal noise can be diagnosed by observing and analyzing the spectrum shape.

[0047] Specifically, the diagnostic distinction between motor whistling and gear meshing noise is based on the differences in their spectral characteristics, speed correlation, and load coupling relationships caused by the differences in their excitation sources (electromagnetic excitation and mechanical meshing excitation).

[0048] Spectral morphology and sidebands: The spectrum of motor whistling is a pure narrow band with a sharp and single main frequency peak. The harmonics are the electromagnetic characteristic orders of the motor (such as the 8th, 16th, and 24th orders), with no obvious sidebands on either side. Although gear meshing noise is also a narrow band, its main frequency is modulated by mechanical factors such as tooth profile error and shaft movement, resulting in regularly spaced sidebands. Furthermore, its harmonics also have sidebands, which is a unique characteristic of mechanical meshing noise.

[0049] Speed ​​correlation: The main frequency of motor whistling is strongly linearly correlated with motor speed, changing proportionally with increases and decreases in motor speed, and is independent of the speed of the steering column or gear shaft. The main frequency of gear meshing noise, however, is strongly correlated with the speed of the steering column or gear shaft.

[0050] Load coupling relationship: The main frequency of motor whistling does not change with the load, only its intensity increases with the increase of motor load (current); the main frequency of gear meshing noise changes with the steering speed, and its intensity increases with the increase of steering rack load (tie rod force). Under the condition of motor idling (no steering operation), the spectral characteristics of motor whistling still exist stably, while the spectral characteristics of gear meshing noise will completely disappear.

[0051] In practice, the following steps can be used for quick and accurate differentiation to avoid misjudgment:

[0052] S61. Observe the dynamic spectrum waterfall diagram to identify whether the main frequency component of the abnormal noise changes linearly with the motor speed or with the steering / gear speed, thereby locking the speed-related attribute of the excitation source.

[0053] S62. Extract the static FFT spectrum during the stable phase of the abnormal noise, and visually check whether there are sidebands with the aforementioned rules on both sides of the main frequency, and verify the characteristics of the judgment in the previous step.

[0054] S63. Design variable operating condition tests, such as changing only the motor load, changing only the steering load, or performing a motor idling test, and observe whether the frequency and peak intensity of the main frequency of the abnormal noise spectrum show the aforementioned different change patterns, thereby completing the final judgment.

[0055] The complete steps for testing using this system are detailed below:

[0056] Steps S1 and S2: First, in the silent chamber, the operator uses modular fixtures to fix the steering system under test (such as a P-EPS system) in the actual vehicle configuration. Then, outside the silent chamber, the axle module of the load simulation component is adjusted to its initial position and connected to both ends of the steering rack via connecting rods (extension rods). The connection point passes through a sealed interface in the silent chamber wall.

[0057] Step S3: Manually rotate the handwheel of the loading assembly (screw lifting mechanism) to drive the tire to press down vertically until a predetermined vertical load (such as a force corresponding to 1 / 4 of the vehicle weight) is applied to the test road surface unit. At this point, the load has been applied to the steering system through the connecting rod.

[0058] Step S4: Close the soundproof room door. Inside, the steering wheel is driven by the steering robot or manually operated through the input of the torque angle sensor according to the preset steering angle-speed curve (such as sinusoidal sweep frequency, angular step).

[0059] Step S5: Throughout Step S3, the data processing system operates automatically. The synchronous acquisition module synchronously records: noise signals (multi-channel), vibration signals (multi-channel), steering wheel torque and angle signals from the interior; load force signals from the connecting rod; and bus signals such as motor current from the ECU. All data is time-stamped to ensure strict synchronization.

[0060] Step S6: After the test, the data analysis module automatically processes the data. The data analysis module runs on the host computer software platform. After receiving the synchronized data, it performs FFT spectrum analysis, order analysis, sound pressure level and psychoacoustic parameter calculation, transmission path analysis, etc., to generate an NVH performance report and accurately locate the source of abnormal noise.

[0061] It is understood that the specific embodiments described above are merely for explaining the relevant invention and not for limiting the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict with each other. Any equivalent structural transformations made based on the content of this specification and drawings, whether directly or indirectly applied to other related technical fields, are similarly included within the scope of protection of this invention.

Claims

1. A vehicle steering NVH testing system, characterized in that, Includes a soundproof room, load simulation components, connecting rods, and a data processing system, among which: The soundproof chamber is used to house the steering system under test; The load simulation component is located outside the quiet chamber and is used to simulate the load acting on the steering system under test when the vehicle is in motion. The connecting rod passes through the wall of the quiet chamber and connects the output end of the load simulation component to the load input end of the steering system under test located inside the quiet chamber. The data processing system includes a torque angle sensor, a load force sensor, a noise sensor, a vibration sensor, a synchronous acquisition module, and a data analysis module. The torque angle sensor is used to acquire torque and angle signals from the input of the steering system. The load force sensor is used to acquire load force signals from the load simulation component. The noise sensor is used to acquire noise signals from the soundproof room. The vibration sensor is used to acquire vibration signals from the soundproof room. The synchronous acquisition module is used to synchronously acquire and record the signals output by the torque angle sensor, load force sensor, noise sensor, and vibration sensor. The data analysis module performs order analysis based on the signals recorded by the synchronous acquisition module. The order analysis uses the speed pulse signal obtained by converting the motor speed signal of the steering system under test as a reference to perform equal-angle resampling on the time-domain signals of the noise signal and vibration signal.

2. The automotive steering NVH testing system according to claim 1, characterized in that, The load simulation component includes an axle module and a loading component. The axle module includes a tire for simulating a wheel and a test road surface unit located under the tire. The tire is perpendicular to the test road surface unit. The loading component applies a vertically downward loading force to the tire. One end of the connecting rod is connected to the tire or the loading component, and the other end of the connecting rod is connected to the load input terminal of the steering system under test.

3. The automotive steering NVH testing system according to claim 2, characterized in that, The surface of the test road surface unit is covered with replaceable friction material.

4. The automotive steering NVH testing system according to claim 3, characterized in that, The loading assembly includes a bracket, a lead screw, a nut, a pressing block, a sleeve, a spring, a connecting block, and a handwheel. The nut is fixedly installed on the bracket. The lead screw is threadedly engaged with the nut. The handwheel is drivenly connected to the lead screw. The sleeve is rotatably connected to the bracket via a bearing. The sleeve has an axial guide space inside. The pressing block is disposed within the guide space of the sleeve and is connected to the lower end of the lead screw. The pressing block is slidably engaged with the inner wall of the sleeve. The spring is sleeved between the pressing block and the connecting block. One end of the connecting block is rigidly connected to the sleeve, and the other end of the connecting block is connected to the wheel center of the tire. The side of the connecting block facing away from the tire has a pin hinged to a connecting rod. The axis of the pin and the rotation axis of the sleeve have an eccentricity in the horizontal plane.

5. The automotive steering NVH testing system according to claim 1, characterized in that, The data processing system further includes a signal acquisition module, which is used to acquire the internal electrical signals of the steering system controller under test. The synchronous acquisition module synchronously acquires the internal electrical signals and signals from the torque angle sensor, load force sensor, noise sensor and vibration sensor to generate a multi-source synchronous signal. The internal electrical signals include at least one of motor speed signal and current signal.

6. The automotive steering NVH testing system according to claim 5, characterized in that, The data analysis module performs at least one of the following based on the multi-source synchronous signal: fast Fourier transform spectrum analysis, order analysis, sound pressure level calculation, psychoacoustic parameter calculation, and transmission path analysis.

7. The automotive steering NVH testing system according to claim 1, characterized in that, The walls of the quilted room are covered with sound-absorbing material, and the static background noise of the quilted room is no more than 30 decibels.

8. A test method using the automotive steering NVH test system as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Install the steering system to be tested onto the bench fixture in the quiet room; S2. Connect the load simulation component located outside the soundproof room to the load input terminal of the steering system under test via a connecting rod passing through the wall of the soundproof room. S3. Operate the load simulation component to apply a simulated load to the steering system under test, and dynamically adjust the load application point according to the steering angle; S4. Perform steering operation at the steering input end of the steering system under test in a quiet room; S5. The noise and vibration signals in the quiet room, the torque and angle signals at the steering input end, and the load force signals transmitted by the connecting rod are synchronously collected through the data processing system. S6. The data analysis module performs order analysis on the synchronously acquired signals to diagnose the source of the abnormal noise.

9. The test method according to claim 8, characterized in that, Determining the source of the abnormal noise includes the following steps: S61. Obtain the motor speed signal of the steering system under test, convert the motor speed signal into an analog speed pulse signal, and then generate a standard speed pulse signal based on the analog speed pulse signal. S62. Using the standard rotational speed pulse signal as a reference, the time-domain vibration signal and the time-domain noise signal are resampled at equal angles to obtain the angular domain vibration signal and the angular domain noise signal. The angular domain vibration signal and the angular domain noise signal are then subjected to Fourier transform to generate a rotational speed-frequency spectrum. S63. Extract the order slice related to the steering system under test from the speed-frequency spectrum, and determine the source of abnormal noise based on the spectral morphology of the order slice.

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