Device and method for detecting noise and fluctuation of electric power steering system

Abstract

The invention discloses an electric power steering system noise and fluctuation detection device and method, and the device comprises a sound insulation structure body which is used for placing an electric power steering system, and the sound insulation structure body is in communication connection with an external upper computer control computer. Mounting of the electric power steering system is completed, an upper computer control computer detects whether the electric power steering system is mounted in place or not through a mounting position sensor, the part number of the steering system is scanned after the electric power steering system is mounted in place, and a sound insulation structure upper cover is closed; detecting whether the electric power steering system and the upper computer control computer are normally connected or not; the upper computer controls the computer to send a constant-speed power-assisted mode instruction to the electric power-assisted steering system, sweep frequency and Fourier transform are carried out on collected noise and vibration data, a system detection noise curve and a frequency data curve are output, and a peak noise value is extracted from system noise curve data.

Description

Technical Field

[0001] The invention relates to a detection device and a detection method for an electric power steering system, in particular to a detection device and a detection method for noise and fluctuation of an electric power steering system, belonging to the technical field of automobile automatic testing. Background Art

[0002] In the development and production of electric power steering systems, more and more attention is paid to noise and fluctuation levels, which directly affect the comfort and driving operability of customers and end users. In the electric power steering system industry, improving the noise and fluctuation performance of the system is a goal that manufacturers continue to pursue.

[0003] When the existing electric power steering system products leave the factory, they are mainly judged by manual identification and testing, and the qualification is subjectively determined, and the judgment basis is vague. The testing environment is interfered by external noise. From the evaluation and testing standards of the electric power steering system noise, the existing testing methods are highly subjective and prone to missed inspections and false inspections of products. The existing testing system has the problem that the equipment test results are saved without data support, and there is not enough data support for the subsequent tracing of the problem parts. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an electric power steering system noise and fluctuation detection device and detection method, which can accurately detect the motor noise and fluctuation level when the electric power steering system is inspected at the factory, detect abnormal parts in time and prevent them from flowing out; at the same time, the detection data can be automatically analyzed and saved, so as to do a good job of product traceability.

[0005] In order to solve the above technical problems, the present invention provides an electric power steering system noise and fluctuation detection device, comprising a sound insulation structure body for placing the electric power steering system, wherein the sound insulation structure body is communicatively connected to an external upper control computer (14); An installation fixing structure is provided at the inner bottom of the sound insulation structure body along the working direction of the electric power steering system. The installation fixing structure is provided at the bottom of the electric power steering system and comprises a first installation slider (5), a second installation slider (6) and a load motor fixing block (7). The first installation slider and the second installation slider have the same structure. Through holes and assembly holes are provided on the tops of the first and second installation sliders, and the first and second installation sliders are fixedly connected to the electric power steering system via T-bolts. The top of the load motor fixing block has an arc-shaped depression, and the top is fixed to the load motor (9) via bolts. The load motor is provided with a coupling, and is connected and fixed to the output shaft of the electric power steering system via the coupling. A first mounting position sensor (8) is fixed to the left side of the load motor (9) via a patch, a second mounting position sensor (10) is fixed above the first mounting slider via a patch, a first data acquisition sensor (12) is adsorbed to the left side of the second mounting slider (6) via a magnetic patch, a second data acquisition sensor (13) is adsorbed to the motor housing of the electric power steering system via a magnetic patch, and a sound collection device (11) is fixed to the bottom plate of the sound insulation structure, 50 cm away from the front of the electric power steering system.

[0006] Furthermore, the sound insulation structure body comprises a left mounting plate (1) and a right mounting plate (3) which are symmetrically and vertically distributed on both sides, a bottom mounting plate (2) is horizontally placed along the bottom of the two, and a top cover (4) which can be opened and closed is rotatably connected to the top of the right mounting plate.

[0007] Furthermore, a rotating shaft (14) is installed on one side of the upper cover, a clamping block (15) is installed on the other side of the upper cover, a side plate (16) is fixedly connected to one side of the left mounting plate, a limiting rod (17) is movably connected inside the side plate, and a nut (18) is installed on the outer wall of the limiting rod.

[0008] Furthermore, a slide rail is provided above the bottom mounting plate, and the first mounting slide block and the second mounting slide block can move forward and backward along the slide rail to form a sliding structure.

[0009] Furthermore, the rear of the slide rail is designed as a slotted structure on the bottom mounting plate, the load motor fixing block is clamped and fixed in the slot, and is arranged parallel to the first mounting slide block and the second mounting slide block.

[0010] Furthermore, the limiting rod and the side plate form a rotating structure, and the limiting rod is arranged in a T-shape. The outer wall of the limiting rod is provided with a thread, and the limiting rod is threadedly connected with the nut.

[0011] A detection method for an electric power steering system noise and fluctuation detection device comprises the following steps: Step 1: Install the electric power steering system: According to actual needs, adjust the position of each installation slider to complete the installation of the electric power steering system. The host computer controls the computer to detect whether the electric power steering system is installed in place through the installation position sensor. After installation, scan the steering system part number and close the sound insulation structure cover; Step 2: Check whether the electric power steering system and the upper computer are connected normally: supply power to the electric power steering system through the upper computer, and execute the handshake procedure to confirm whether the working status of the electric power steering system is normal. If the electric power steering system works normally, the upper computer starts the load motor to output the rated load; Step 3: The host computer controls the computer to send a uniform speed power-assist mode command to the electric power steering system: the electric power steering system outputs power at the rated speed, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads them to the host computer control computer for data aggregation; Step 4: The host computer controls the computer to perform frequency sweep and Fourier transform on the noise and vibration data collected in the above steps, and outputs the system detection noise curve and frequency data curve; Step 5. Extract the peak noise value from the system noise curve data: First, perform noise evaluation through the set maximum value, minimum value, and peak value. After the noise amplitude comparison is passed, compare the system noise curve data with the standard system noise data for overlap to evaluate the steering system noise level; perform low-pass filtering on the frequency distribution from the system frequency curve data, obtain the low-frequency fluctuation amount through the filtered low-frequency signal, perform band-pass filtering on the frequency distribution, obtain the high-frequency fluctuation amount through the filtered high-frequency signal, and compare the low-frequency fluctuation amount with the high-frequency fluctuation amount to evaluate the steering system fluctuation level.

[0012] Furthermore, the step 3 includes at least five uniform speed power-assisting mode instructions. When set to uniform speed power-assisting mode 1 instruction, the electric power steering system outputs power-assisting at a rated speed of 500 rpm; when set to uniform speed power-assisting mode 2 instruction, the electric power steering system outputs power-assisting at a rated speed of 1000 rpm; when set to uniform speed power-assisting mode 3 instruction, the electric power steering system outputs power-assisting at a rated speed of 1500 rpm; when set to uniform speed power-assisting mode 4 instruction, the electric power steering system outputs power-assisting at a rated speed of 2000 rpm; when set to uniform speed power-assisting mode 5 instruction, the electric power steering system outputs power-assisting at a rated speed of 2500 rpm.

[0013] Furthermore, in step 8, the host computer controls the computer to perform frequency domain analysis and Fourier transform on the noise and vibration data collected from power-assisting modes 1 to 5: The Fourier transform formula is:

[0014] Fourier transform is used to convert a signal from time domain to frequency domain. The basic principle is to decompose a periodic signal into a superposition of a series of sine and cosine functions; through Fourier series expansion, a signal is represented as a superposition of a continuous spectrum, and such a spectrum can be used to analyze the frequency components and relative strength of the signal; When the output shaft executes the instructions of power-assist mode 1 to power-assist mode 5, it will rotate three times clockwise and three times counterclockwise. The vibration data of the second clockwise and counterclockwise rotations are selected as the data calculation area. After Fourier transforming the vibration data in the data calculation interval, the system frequency curve is obtained. The amplitude and amplitude curve of the noise signal from power-assist mode 1 to power-assist mode 5 in the data calculation interval are extracted through time domain analysis.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The external sound insulation structure mainly solves the external interference of the existing detection method on the detection results in the noisy environment of the existing production line; 2. The installation structure of the first installation slide block and the second installation slide block is universal and can be adapted to the offline detection of multiple products; 3. The upper computer determines the installation result through the first installation position sensor and the second installation position sensor, eliminating manual operation and improving the accuracy of result judgment compared with manual judgment; 4. The five power-assist modes cover the main operating conditions of the electric power steering system. The determination of the operating results of the five working modes improves the comprehensiveness of the detection process; 5. The sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor. The application of three data collection devices avoids differences in the manual judgment process; 6. The detection host computer controls the entire detection process and summarizes and compares the results, which improves the quality of the steering system's off-line detection and is conducive to the traceability of subsequent product off-line detection reports. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the detection equipment of the present invention.

[0017] Figure 2 for Figure 1 Top view of the .

[0018] Figure 3 It is the noise data curve of the electric power assist system of the present invention.

[0019] Figure 4 It is the vibration data curve of the electric power assist system of the present invention.

[0020] Description of the drawings: 1-left mounting plate of the sound insulation structure, 2-bottom mounting plate of the sound insulation structure, 3-right mounting plate of the sound insulation structure, 4-upper cover of the sound insulation structure, 5-first mounting slider, 6-second mounting slider, 7-load motor fixing block, 8-first mounting position sensor, 9-load motor, 10-second mounting position sensor, 11-sound collection device, 12-first data collection sensor, 13-second data collection sensor, 14-host control computer. DETAILED DESCRIPTION

[0021] This embodiment provides a noise and fluctuation detection device for an electric power steering system. Figure 1-2 As shown, it includes a sound insulation structure body for placing the electric power steering system and a host control computer 14 that is communicatively connected to the sound insulation structure body.

[0022] The sound insulation structure body comprises a left mounting plate 1 of the sound insulation structure, a bottom mounting plate 2 of the sound insulation structure, a right mounting plate 3 of the sound insulation structure and a top cover 4 of the sound insulation structure. The left mounting plate of the sound insulation structure and the right mounting plate of the sound insulation structure are vertically symmetrically distributed on both sides, the bottom mounting plate of the sound insulation structure is horizontally placed at the bottom of the two, the top cover of the sound insulation structure is rotatably connected to the top of the right mounting plate of the sound insulation structure, and a clamping block is installed on the other side of the top cover 4 of the sound insulation structure, one side of the left mounting plate 1 of the sound insulation structure is fixedly connected to a side plate, the inner movable connection of the side plate is provided with a limit rod, and a nut is installed on the outer wall of the limit rod, the top cover 4 of the sound insulation structure forms a rotating structure with the right mounting plate 3 of the sound insulation structure through a rotating shaft 14, and the clamping block is a slotted design, the limit rod and the side plate form a rotating structure, and the limit rod is T-shaped, the outer wall of the limit rod is provided with a thread, and the limit rod is threadedly connected with the nut, which can be convenient for isolating external noise.

[0023] At the same time, the first mounting slider 5, the second mounting slider 6 and the load motor fixing block 7 are sequentially installed on the upper inner part of the mounting plate at the bottom of the sound insulation structure, and the three are arranged along the working direction of the electric power steering system. Among them, the first and second mounting sliders have the same structure, and both are provided with through holes and assembly holes on the top, and are fixedly connected to the electric power steering system by T-bolts. The top of the load motor fixing block has an arc-shaped depression, which is installed with the load motor 9 by bolts. The load motor is provided with a coupling, which is connected and fixed to the output shaft of the electric power steering system by the coupling. In addition, a slide rail is also arranged above the mounting plate at the bottom of the sound insulation structure, and the first mounting slider and the second mounting slider can move forward and backward along the slide rail according to the actual working conditions. Behind the slide rail, the mounting plate at the bottom of the sound insulation structure is designed as a slotted structure, and the load motor fixing block is clamped and fixed in the slot, and is arranged parallel to the first mounting slider and the second mounting slider.

[0024] A first mounting position sensor 8 is fixed to the left side of the load motor through a patch, a second mounting position sensor 10 is fixed to the top of the first mounting slider through a patch, a first data acquisition sensor 12 is adsorbed on the left side of the second mounting slider 6 through a magnetic patch, and a second data acquisition sensor 13 is adsorbed on the motor housing of the electric power steering system through a magnetic patch. The sound collection device 11 is fixed on the bottom plate of the sound insulation structure, 50 cm away from the front of the electric power steering system.

[0025] This embodiment also proposes a method for detecting noise and fluctuation of an electric power steering system, comprising the following steps: Step 1, install the electric power steering system: according to the actual working conditions, adjust the positions of the first installation slider and the second installation slider respectively, match the top through-holes, assembly holes and the installation position of the electric power steering system, and complete the installation of the electric power steering system. The upper computer controls the computer to detect whether the electric power steering system is installed in place through the installation position sensor. After installation, scan the steering system part number and close the sound insulation structure cover to form a closed space; Step 2, check whether the electric power steering system and the host computer are connected normally: the host computer controls the electric power steering system to supply power, and executes the handshake procedure to confirm whether the working state of the electric power steering system is normal. If the electric power steering system works normally, the host computer controls the load motor to output the rated load; Step 3, the host computer controls the computer to send a uniform speed power-assistance mode 1 instruction to the electric power steering system: the electric power steering system outputs power assistance at a rated speed of 500 rpm, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads them to the host computer control computer for data aggregation; Step 4, the host computer controls the computer to send a uniform speed power-assistance mode 2 instruction to the electric power steering system: the electric power steering system outputs power assistance at a rated speed of 1000 rpm, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads it to the host computer for data aggregation; Step 5, the host computer controls the computer to send three instructions of the uniform speed power-assistance mode to the electric power-assistance steering system: the electric power-assistance steering system outputs power assistance at a rated speed of 1500 rpm, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads them to the host computer for data aggregation; Step 6, the host computer controls the computer to send four instructions of the uniform speed power-assistance mode to the electric power-assistance steering system: the electric power-assistance steering system outputs power assistance at a rated speed of 2000 rpm, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads them to the host computer for data aggregation; Step 7, the host computer controls the computer to send the uniform speed power-assistance mode five instructions to the electric power-assistance steering system: the electric power-assistance steering system outputs power at a rated speed of 2500 rpm, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads them to the host computer for data aggregation; Step 8: After the five instructions are executed, the test bench host computer performs data analysis. The test bench host computer performs frequency domain analysis and Fourier transform on the vibration data collected from power-assisting mode 1 to power-assisting mode 5.

[0026] The Fourier transform formula is:

[0027] Fourier transform is an important mathematical tool used to convert a signal from the time domain to the frequency domain. The basic principle is to decompose a periodic signal into a superposition of a series of sine and cosine functions. Through Fourier series expansion, a signal can be represented as a superposition of a continuous spectrum. Such a spectrum can be used to analyze the frequency components and relative strength of the signal.

[0028] When the output shaft executes the instructions of power-assist mode 1 to power-assist mode 5, it will rotate three times clockwise and three times counterclockwise in sequence. The data of the second clockwise and counterclockwise rotation of power-assist mode 1 to power-assist mode 5 are selected as the data calculation range. Set the output shaft stroke to S, and the data calculation range is 30%~70% of the set value S.

[0029] The vibration data of power-assist mode 1 to power-assist mode are selected from the data calculation interval, and the system frequency curve can be obtained by Fourier transforming the vibration data. The noise signals of power-assist mode 1 to power-assist mode 5 are selected from the data calculation interval, and the amplitude and amplitude curve of the noise signal are extracted through time domain analysis.

[0030] Step 9. Extract the peak noise value from the system noise curve data: First, judge the noise by setting the maximum value, minimum value and peak value. Generally, 42DB can be used as the typical setting value for noise amplitude comparison, and 3-5DB above and below can be used as the judgment range. After the noise amplitude comparison is passed, the system noise curve data is compared with the standard system noise data for coincidence to judge the steering system noise level; perform low-pass filtering on the frequency distribution from the system frequency curve data, obtain the low-frequency fluctuation amount through the filtered low-frequency signal, perform band-pass filtering on the frequency distribution, obtain the high-frequency fluctuation amount through the filtered high-frequency signal, and judge the steering system fluctuation level by comparing the low-frequency fluctuation amount with the high-frequency fluctuation amount.

[0031] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. An electric power steering system noise and fluctuation detection device, characterized in that: It comprises a sound insulation structure body for accommodating an electric power steering system, wherein the sound insulation structure body is communicatively connected to an external host control computer (14); An installation fixing structure is provided at the inner bottom of the sound insulation structure body along the working direction of the electric power steering system. The installation fixing structure is provided at the bottom of the electric power steering system and comprises a first installation slider (5), a second installation slider (6) and a load motor fixing block (7). The first installation slider and the second installation slider have the same structure. Through holes and assembly holes are provided on the tops of the first and second installation sliders, and the first and second installation sliders are fixedly connected to the electric power steering system via T-bolts. The top of the load motor fixing block has an arc-shaped depression, and the top is fixed to the load motor (9) via bolts. The load motor is provided with a coupling, and is connected and fixed to the output shaft of the electric power steering system via the coupling. A first mounting position sensor (8) is fixed to the left side of the load motor (9) via a patch, a second mounting position sensor (10) is fixed above the first mounting slider via a patch, a first data acquisition sensor (12) is adsorbed to the left side of the second mounting slider (6) via a magnetic patch, a second data acquisition sensor (13) is adsorbed to the motor housing of the electric power steering system via a magnetic patch, and a sound collection device (11) is fixed to the bottom plate of the sound insulation structure, 50 cm away from the front of the electric power steering system.

2. The electric power steering system noise and fluctuation detection device according to claim 1, characterized in that: The sound insulation structure body comprises a left mounting plate (1) and a right mounting plate (3) which are symmetrically and vertically distributed on both sides, a bottom mounting plate (2) is horizontally placed along the bottom of the two, and an openable and closable upper cover (4) is rotatably connected to the top of the right mounting plate.

3. The electric power steering system noise and fluctuation detection device according to claim 2, characterized in that: A rotating shaft (14) is installed on one side of the upper cover, a clamping block (15) is installed on the other side of the upper cover, a side plate (16) is fixedly connected to one side of the left mounting plate, a limiting rod (17) is movably connected inside the side plate, and a nut (18) is installed on the outer wall of the limiting rod.

4. The electric power steering system noise and fluctuation detection device according to claim 2, characterized in that: A slide rail is also arranged above the bottom mounting plate, and the first mounting slide block and the second mounting slide block can move forward and backward along the slide rail to form a sliding structure.

5. The electric power steering system noise and fluctuation detection device according to claim 2, characterized in that: The rear of the slide rail is designed as a slotted structure on the bottom mounting plate, and the load motor fixing block is clamped and fixed in the slot and is arranged parallel to the first mounting slide block and the second mounting slide block.

6. The electric power steering system noise and fluctuation detection device according to claim 3, characterized in that: The limiting rod and the side plate form a rotating structure, and the limiting rod is T-shaped.

7. The electric power steering system noise and fluctuation detection device according to claim 6, characterized in that: The outer wall of the limiting rod is provided with a thread, and the limiting rod is threadedly connected with the nut.

8. A detection method for the electric power steering system noise and fluctuation detection device according to claim 1, characterized in that: The steps include: Step 1: Install the electric power steering system: According to actual needs, adjust the position of each installation slider to complete the installation of the electric power steering system. The host computer controls the computer to detect whether the electric power steering system is installed in place through the installation position sensor. After installation, scan the steering system part number and close the sound insulation structure cover; Step 2: Check whether the electric power steering system and the upper computer are connected normally: supply power to the electric power steering system through the upper computer, and execute the handshake procedure to confirm whether the working status of the electric power steering system is normal. If the electric power steering system works normally, the upper computer starts the load motor to output the rated load; Step 3: The host computer controls the computer to send a uniform speed power-assist mode command to the electric power steering system: the electric power steering system outputs power at the rated speed, the sound collection device collects sound data, the first data collection sensor collects vibration data at the transmission structure, and the second data collection sensor collects vibration data at the motor and uploads them to the host computer control computer for data aggregation; Step 4: The host computer controls the computer to perform frequency sweep and Fourier transform on the noise and vibration data collected in the above steps, and outputs the system detection noise curve and frequency data curve; Step 5. Extract the peak noise value from the system noise curve data: First, perform noise evaluation through the set maximum value, minimum value, and peak value. After the noise amplitude comparison is passed, compare the system noise curve data with the standard system noise data for overlap to evaluate the steering system noise level; perform low-pass filtering on the frequency distribution from the system frequency curve data, obtain the low-frequency fluctuation amount through the filtered low-frequency signal, perform band-pass filtering on the frequency distribution, obtain the high-frequency fluctuation amount through the filtered high-frequency signal, and compare the low-frequency fluctuation amount with the high-frequency fluctuation amount to evaluate the steering system fluctuation level.

9. The detection method of the electric power steering system noise and fluctuation detection device according to claim 8, characterized in that: The step 3 includes at least five uniform speed power-assisting mode instructions. When the uniform speed power-assisting mode 1 instruction is set, the electric power-assisting system outputs power-assisting at a rated speed of 500 rpm; when the uniform speed power-assisting mode 2 instruction is set, the electric power-assisting system outputs power-assisting at a rated speed of 1000 rpm; when the uniform speed power-assisting mode 3 instruction is set, the electric power-assisting system outputs power-assisting at a rated speed of 1500 rpm; when the uniform speed power-assisting mode 4 instruction is set, the electric power-assisting system outputs power-assisting at a rated speed of 2000 rpm; when the uniform speed power-assisting mode 5 instruction is set, the electric power-assisting system outputs power-assisting at a rated speed of 2500 rpm.

10. The detection method of the electric power steering system noise and fluctuation detection device according to claim 8, characterized in that: In step 8, the host computer controls the computer to perform frequency domain analysis and Fourier transform on the noise and vibration data collected from power-assisting modes 1 to 5: The Fourier transform formula is: Fourier transform is used to convert a signal from time domain to frequency domain. The basic principle is to decompose a periodic signal into a superposition of a series of sine and cosine functions; through Fourier series expansion, a signal is represented as a superposition of a continuous spectrum, and such a spectrum can be used to analyze the frequency components and relative strength of the signal; When the output shaft executes the instructions of power-assist mode 1 to power-assist mode 5, it will rotate three times clockwise and three times counterclockwise. The vibration data of the second clockwise and counterclockwise rotations are selected as the data calculation area. After Fourier transforming the vibration data in the data calculation interval, the system frequency curve is obtained. The amplitude and amplitude curve of the noise signal from power-assist mode 1 to power-assist mode 5 in the data calculation interval are extracted through time domain analysis.

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