Static performance test equipment for automobile tie rod ball head

Abstract

The invention discloses automobile tie rod ball static performance test equipment, belongs to the technical field of automobile part tests, and solves the problems that in an automobile tie rod ball static performance test, the initial swing torque of a batch of products is qualified, the starting torque is attenuated to be unqualified after 24-hour load standing retest, the torque is increased after the same sample is continuously rotated and tested, and the test efficiency is low. And the judgment is invalid due to unstable data. Comprising a servo motor, a driving chuck which is in transmission connection with a driving path of the servo motor, a plurality of groups of rotating seats which can move along the length direction of a rotor shaft of the servo motor, and a driven chuck which is coaxial with the rotor shaft of the servo motor and is rotationally connected with the rotating seats. According to the invention, reliable online quality determination is realized through temperature control and voltage stabilization of the self-adaptive power thermal management module, self-calibration and error elimination of the main control module, regeneration of a composite signal excitation ball head, synchronous acquisition of multi-mode signals, multi-feature fusion determination of a state after analysis and feature extraction, and distinguishing of ball bowl creep deformation and lubricating grease thixotropy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile accessory test, in particular to a static performance test equipment for automobile pull rod ball head. BACKGROUND

[0002] The swing torque test of the automobile pull rod ball head is carried out according to the QC / T648-2015 standard, the ball head dustproof device is first disassembled, the specified lubricating grease is injected, and then the ball swing torque tester is assembled to make the ball pin at the designed plane, and the swing is carried out at a frequency of 4-6 times per minute within the designed swing angle of 80%-90%, and the maximum torque of the 6th time is recorded after 5 times of reciprocating, and the abnormal torque can reflect the potential problems of the ball head, which is the key of quality control, the ball swing torque tester fixes the ball head through the clamp, drives the ball pin to swing through the driving mechanism, measures the resistance torque through the torque sensor, has the functions of accurate control of swing angle and frequency, high dynamic sampling, wide load adaptability, and is also integrated with an environmental simulation cabin, and can meet the test requirements of different vehicle models.

[0003] In the static performance test and detection process of the automobile pull rod ball head, all products in a batch are qualified in the initial swing torque test, but after the specified 24-hour load static placement, the starting torque is significantly attenuated to the unqualified range, however, after the continuous rotation test of the same "unqualified" sample, the torque value rises again, resulting in extremely unstable data and determination failure, which will directly lead to misjudgment of qualified products and batch delivery stagnation, causing quality crisis and forcing enterprises to invest high additional costs for weeks of root cause diagnosis.

[0004] Therefore, a static performance test equipment for automobile pull rod ball head is proposed to solve or alleviate the above problems. SUMMARY

[0005] The present application relates to the technical field of automobile accessory test, in particular to a static performance test equipment for automobile pull rod ball head.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] The application discloses a static performance test device for a ball head of an automobile pull rod, which comprises a servo motor, a driving chuck connected to a driving path of the servo motor, a plurality of groups of rotating seats which are displaceable along the length direction of a rotating shaft of the servo motor, a driven chuck coaxial with the rotating shaft of the servo motor and rotatably connected to the rotating seat, a torque sensor and a rotary encoder connected to the driven chuck, and a ball head time-varying characteristic online identification circuit electrically connected to the torque sensor and the rotary encoder and connected to the servo motor through a motor encoder, wherein the ball head time-varying characteristic online identification circuit applies a composite electroacoustic excitation to the measured pull rod ball head and synchronously collects a multi-modal dynamic response signal of the pull rod ball head to extract a dynamic characteristic parameter, so as to identify the viscoelastic creep state of a high polymer material in the ball head and the thixotropic characteristic of grease and then diagnose and determine an abnormal mode of time-varying characteristic.

[0008] Preferably, the ball head time-varying characteristic online identification circuit comprises a piezoelectric ceramic exciter mounted on the inner side of the driving chuck, a three-axis micro-vibration accelerometer and an acoustic emission sensor for being mounted on the measured pull rod ball head, and a master control and computing core module, wherein the master control and computing core module is connected with a wide-band piezoelectric ceramic exciter driving circuit module, a high dynamic range synchronous sampling sensor signal conditioning circuit module, an analog computing mechanical impedance analysis front-end module, a deterministic delay and multi-channel synchronous trigger management module, an embedded real-time parameter identification coprocessor module, and a self-adaptive closed-loop power and heat management module; the piezoelectric ceramic exciter is connected with the wide-band piezoelectric ceramic exciter driving circuit module; the output ends of the torque sensor, the acoustic emission sensor and the three-axis micro-vibration accelerometer are connected to the high dynamic range synchronous sampling sensor signal conditioning circuit module; the torque sensor and the rotary encoder are connected with the analog computing mechanical impedance analysis front-end module; the trigger signal output end of the deterministic delay and multi-channel synchronous trigger management module is respectively connected to the synchronous trigger input end of the wide-band piezoelectric ceramic exciter driving circuit module and the sampling trigger input end of the high dynamic range synchronous sampling sensor signal conditioning circuit module; the deterministic delay and multi-channel synchronous trigger management module is connected with the servo motor through the motor encoder; the master control and computing core module and the embedded real-time parameter identification coprocessor module are connected with an upper computer through an industrial Ethernet bus; and the power output end of the self-adaptive closed-loop power and heat management module provides power supply.

[0009] Preferably, the master control and computing core module comprises an SoC chip, a DDR3 memory and a Flash memory, wherein the SoC chip is connected with the DDR3 memory and the Flash memory, and the SoC chip is connected with the interfaces of the modules through the input and output interfaces thereof.

[0010] Preferably, the wideband piezoelectric ceramic exciter drive circuit module comprises a waveform generator, a high-voltage power operational amplifier, a digital isolator, the positive and negative differential output pins of the waveform generator are connected to the non-inverting input pin of the high-voltage power operational amplifier through the first and second coupling capacitors, the serial clock pin, the serial data input pin and the chip select pin of the waveform generator are connected to the serial peripheral interface of the host and computing core module through the digital isolator, the power pin of the high-voltage power operational amplifier is connected to the power supply, the output pin of the high-voltage power operational amplifier is connected to the positive electrode of the piezoelectric ceramic exciter through the current sampling resistor, the negative electrode of the piezoelectric ceramic exciter is grounded, and the sense pin of the high-voltage power operational amplifier is connected to the output pin of the high-voltage power operational amplifier through the first resistor, and the negative input pin of the high-voltage power operational amplifier is grounded through the second resistor.

[0011] Preferably, the high-dynamic-range synchronous sampling sensing signal conditioning circuit module comprises a programmable gain amplifier, an AD7124-8 analog-to-digital converter, an ADS127L01 analog-to-digital converter, and an LTC1068 switched-capacitor filter, the positive voltage input pin of the programmable gain amplifier is connected to the signal output end of the torque sensor through an input resistor, the voltage output pin of the programmable gain amplifier is connected to the analog input zero channel pin of the AD7124-8 analog-to-digital converter, the signal output end of the micro-vibration accelerometer is connected to the analog input two positive pin of the ADS127L01 analog-to-digital converter through a third coupling capacitor, the analog input two negative pin of the ADS127L01 analog-to-digital converter is grounded through a fourth coupling capacitor, the signal output end of the acoustic emission sensor is connected to the analog input three channel pin of the AD7124-8 analog-to-digital converter through a fifth coupling capacitor, the serial clock pin, the serial data input pin, the serial data output pin and the chip select pin of the AD7124-8 analog-to-digital converter are connected to the first serial peripheral interface of the host and computing core module, the signal input pin of the LTC1068 switched-capacitor filter is connected to the voltage output pin of the programmable gain amplifier, the signal output pin of the LTC1068 switched-capacitor filter is connected to the analog input one channel pin of the AD7124-8 analog-to-digital converter, the clock input pin of the LTC1068 switched-capacitor filter receives the clock signal provided by the deterministic delay and multi-channel synchronous trigger management module, and the frequency selection A pin and the frequency selection B pin of the LTC1068 switched-capacitor filter set the cutoff frequency of the filter through a resistor voltage dividing network.

[0012] Preferably, the analog computing mechanical impedance analysis front-end module comprises an AD734 analog multiplier-divider, an OPA2182 precision operational amplifier and an AD8302 phase detector, the X-input pin of the AD734 analog multiplier-divider is connected to the output signal of the torque sensor through a third resistor, the Y-input pin of the AD734 analog multiplier-divider is connected to the angular velocity voltage signal processed by the analog differentiator of the encoder signal through a fourth resistor, the output pin of the AD734 analog multiplier-divider is connected to the analog-to-digital conversion input channel of the host and computing core module through a fifth resistor, the non-inverting input terminal of the OPA2182 precision operational amplifier is connected to the A-phase signal of the rotary encoder through a sixth resistor, the inverting input terminal of the OPA2182 precision operational amplifier is connected to the B-phase signal of the rotary encoder through a seventh resistor, the output terminal of the OPA2182 precision operational amplifier is connected to the Y2-input pin of the AD734 analog multiplier-divider, the non-inverting input pin of the AD8302 phase detector is connected to the excitation signal generated by the wideband piezoelectric ceramic actuator driving circuit module through a sixth coupling capacitor, the inverting input pin of the AD8302 phase detector is connected to the response signal of the high-dynamic-range synchronous sampling sensing signal conditioning circuit module through a seventh coupling capacitor, and the phase voltage output pin of the AD8302 phase detector is connected to the analog-to-digital conversion input channel of the host and computing core module through an eighth resistor.

[0013] Preferably, the deterministic delay and multi-channel synchronous trigger management module comprises a Si5338 multi-output clock generator and a field programmable gate array, the clock zero positive differential output pin and the clock zero negative differential output pin of the Si5338 multi-output clock generator are connected to the multi-region clock controller clock input pin of the field programmable gate array, the serial data pin and the serial clock pin of the Si5338 multi-output clock generator are connected to the host and computing core module, the input-output zero pin of the field programmable gate array is connected to the synchronous trigger input terminal of the wideband piezoelectric ceramic actuator driving circuit module, the input-output one pin of the field programmable gate array is connected to the sampling trigger input terminal of the high-dynamic-range synchronous sampling sensing signal conditioning circuit module, the input-output two pin of the field programmable gate array is connected to the reset input terminal of the analog computing mechanical impedance analysis front-end module, and the joint test action group test clock pin, the joint test action group test mode selection pin, the joint test action group test data input pin and the joint test action group test data output pin of the field programmable gate array are connected to the joint test action group interface of the host and computing core module.

[0014] Preferably, the embedded real-time parameter recognition coprocessor module comprises a TMS320C6748 digital signal processor and an IC dynamic random access memory, an external memory interface data bus of the TMS320C6748 digital signal processor is connected to a general input / output pin of a programmable logic end of the master control and computing core module, an external memory interface address bus of the TMS320C6748 digital signal processor is connected to a general input / output pin of a programmable logic end of the master control and computing core module, a chip select two pin, an external memory interface write enable pin and an external memory interface output enable pin of the TMS320C6748 digital signal processor are connected to a general input / output pin of a programmable logic end of the master control and computing core module, a double data rate data bus of the TMS320C6748 digital signal processor is connected to the IC dynamic random access memory, double data rate address bus zero to fourteen pins of the TMS320C6748 digital signal processor are connected to the IC dynamic random access memory, and a double data rate storage area address bus of the TMS320C6748 digital signal processor is connected to a storage area address bus of the IC dynamic random access memory.

[0015] Preferably, the adaptive closed-loop power and thermal management module comprises a negative temperature coefficient thermistor, an OPA2182 differential amplifier, a TPS7A4700 low dropout linear regulator, an LTM4644 switching regulator and a thermoelectric cooler, and a MAX1968 thermoelectric cooler driver, a voltage input pin of the TPS7A4700 low dropout linear regulator is connected to a 12V power supply, a voltage output pin of the TPS7A4700 low dropout linear regulator outputs a 5V power supply, a ground pin of the TPS7A4700 low dropout linear regulator is grounded, a voltage input pin of the LTM4644 switching regulator is connected to a 5V power supply, a voltage output pin of the LTM4644 switching regulator outputs a 0.1V voltage, a power supply ground pin of the LTM4644 switching regulator is connected to a digital ground, the negative temperature coefficient thermistor is attached to a SoC chip in the master control and computing core module, the negative temperature coefficient thermistor is connected to an input end of the OPA2182 differential amplifier, an output end of the OPA2182 differential amplifier is connected to a temperature monitoring pin of the MAX1968 thermoelectric cooler driver, the thermoelectric cooler is installed on a master control radiator of the SoC chip in the master control and computing core module, an output high pin and an output low pin of the MAX1968 thermoelectric cooler driver are connected to the thermoelectric cooler, a serial data pin and a serial clock pin of the MAX1968 thermoelectric cooler driver are connected to the master control and computing core module.

[0016] Preferably, the workbench, the mounting frame fixedly connected to the workbench, the speed reducer mounted on the mounting frame, the electric slide rail arranged on the workbench, the servo motor is fixedly connected to the mounting frame, and the servo motor is in transmission connection with the input end of the speed reducer, the output end of the speed reducer is in coaxial transmission connection with the driving chuck, and the rotating seat is fixedly connected to the sliding seat of the electric slide rail.

[0017] The application has the following beneficial effects:

[0018] The application controls temperature and stabilizes voltage through the adaptive power thermal management module, the main control module starts self-calibration to eliminate errors, a composite excitation signal is regenerated to drive the piezoelectric ceramic excitation ball head, multi-modal signals such as torque and vibration are synchronously collected, parameters are analyzed and features are extracted through analog calculation and a DSP coprocessor, finally, the state is determined through multi-feature fusion, the high polymer ball bowl creep and the grease thixotropy are distinguished, and reliable online quality determination is realized. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 It is a structural schematic diagram of the application.

[0021] Figure 2 It is a structural block diagram of the ball head time-varying characteristic online identification circuit in the application.

[0022] 1, workbench; 2, electric slide rail; 3, sliding seat; 4, rotating seat; 5, passive chuck; 6, torque sensor; 7, mounting seat; 8, servo motor; 9, speed reducer; 10, driving chuck; 11, rotary encoder; 12, motor encoder; 13, piezoelectric ceramic exciter; 14, main control and calculation core module; 15, wideband piezoelectric ceramic exciter driving circuit module; 16, high dynamic range synchronous sampling sensing signal conditioning circuit module; 17, analog calculation mechanical impedance analysis front-end module; 18, deterministic delay and multi-channel synchronous trigger management module; 19, embedded real-time parameter identification coprocessor module; 20, adaptive closed-loop power and thermal management module. DETAILED DESCRIPTION

[0023] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0025] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0026] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0027] In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] A static performance test device for automobile pull rod ball head, such as Figure 1As shown, the system includes a worktable 1, a mounting bracket fixedly connected to the worktable 1, a reducer 9 mounted on the mounting bracket, an electric slide rail 2 set on the worktable 1, a servo motor 8, an active chuck 10 driven by the servo motor 8, multiple sets of rotating seats 4 displaceable along the length of the rotor shaft of the servo motor 8, a passive chuck 5 coaxial with the rotor shaft of the servo motor 8 and rotatably connected to the rotating seats 4, a torque sensor 6 and a rotary encoder 11 driven by the passive chuck 5, and a ball head time-varying characteristic online identification circuit electrically connected to the torque sensor 6 and the rotary encoder 11 and connected to the servo motor 8 through a motor encoder 12. The servo motor 8 is fixedly connected to the mounting bracket and driven by the input end of the reducer 9. The output end of the reducer 9 is driven by the active chuck 10 coaxially. The rotating seats 4 are fixedly connected to the slide seats 3 of the electric slide rail 2.

[0030] like Figure 2 As shown, the online identification circuit for the time-varying characteristics of the ball joint applies a composite electroacoustic excitation to the ball joint of the test tie rod and simultaneously acquires its multimodal dynamic response signal to extract dynamic characteristic parameters. This allows for the identification of the viscoelastic creep state of the polymer material inside the ball joint and the thixotropic properties of the lubricating grease, followed by diagnosis and determination of abnormal time-varying characteristic modes. The online identification circuit for the time-varying characteristics of the ball joint includes a piezoelectric ceramic exciter 13 installed inside the active chuck 10, a triaxial micro-vibration accelerometer and acoustic emission sensor installed on the ball joint of the test tie rod, and a main control and computing core module 14. The main control and computing core module 14 is connected to a wideband piezoelectric ceramic exciter drive circuit module 15, a high dynamic range synchronous sampling sensor signal conditioning circuit module 16, an analog calculation mechanical impedance analysis front-end module 17, a deterministic delay and multi-channel synchronous trigger management module 18, an embedded real-time parameter identification coprocessor module 19, and an adaptive closed-loop power and thermal management module 20. The piezoelectric ceramic... The exciter 13 is connected to the broadband piezoelectric ceramic exciter drive circuit module 15. The outputs of the torque sensor 6, acoustic emission sensor, and triaxial micro-vibration accelerometer are all connected to the high dynamic range synchronous sampling sensor signal conditioning circuit module 16. The torque sensor 6 and rotary encoder 11 are both connected to the analog calculation mechanical impedance analysis front-end module 17. The trigger signal output of the deterministic delay and multi-channel synchronous trigger management module 18 is connected to the synchronous trigger input of the broadband piezoelectric ceramic exciter drive circuit module 15 and the sampling trigger input of the high dynamic range synchronous sampling sensor signal conditioning circuit module 16, respectively. The deterministic delay and multi-channel synchronous trigger management module 18 is connected to the servo motor 8 through the motor encoder 12. The main control and calculation core module 14 and the embedded real-time parameter identification coprocessor module 19 are connected to the host computer through the industrial Ethernet bus. The power output of the adaptive closed-loop power and thermal management module 20 provides power.

[0031] The main control and computing core module 14 includes a SoC chip, DDR3 memory, and Flash memory. The SoC chip is connected to the DDR3 memory and Flash memory, and the SoC chip is connected to the interfaces of each module through its input / output interfaces.

[0032] The wideband piezoelectric ceramic exciter drive circuit module 15 includes a waveform generator, a high-voltage power operational amplifier, and a digital isolator. The positive differential output pin and negative differential output pin of the waveform generator are connected to the non-inverting input pin of the high-voltage power operational amplifier through a first coupling capacitor and a second coupling capacitor. The serial clock pin, serial data input pin, and chip select pin of the waveform generator are connected to the serial peripheral interface of the main control and computing core module 14 through the digital isolator. The power supply pin of the high-voltage power operational amplifier is powered on. The output pin of the high-voltage power operational amplifier is connected to the positive terminal of the piezoelectric ceramic exciter 13 through a current sampling resistor. The negative terminal of the piezoelectric ceramic exciter 13 is grounded. The sensing pin of the high-voltage power operational amplifier is connected to the output pin of the high-voltage power operational amplifier through a first resistor. The negative input pin of the high-voltage power operational amplifier is grounded through a second resistor.

[0033] The high dynamic range synchronous sampling sensor signal conditioning circuit module 16 includes a programmable gain amplifier, an AD7124-8 analog-to-digital converter (ADC), an ADS127L01 ADC, and an LTC1068 switched-capacitor filter. The positive voltage input pin of the programmable gain amplifier is connected to the signal output terminal of the torque sensor 6 via an input resistor. The voltage output pin of the programmable gain amplifier is connected to the analog input zero-channel pin of the AD7124-8 ADC. The signal output terminal of the micro-vibration accelerometer is connected to the two positive analog input pins of the ADS127L01 ADC via a third coupling capacitor. The two negative analog input pins of the ADS127L01 ADC are grounded via a fourth coupling capacitor. The signal output terminal of the acoustic emission sensor is connected to the AD7124-8 ADC via a fifth coupling capacitor. The analog input three-channel pins of the digital-to-digital converter, the serial clock pin, serial data input pin, serial data output pin, and chip select pin of the AD7124-8 analog-to-digital converter are connected to the first serial peripheral interface of the main control and computing core module 14. The signal input pin of the LTC1068 switched-capacitor filter is connected to the voltage output pin of the programmable gain amplifier. The signal output pin of the LTC1068 switched-capacitor filter is connected to the analog input one-channel pin of the AD7124-8 analog-to-digital converter. The clock input pin of the LTC1068 switched-capacitor filter receives the clock signal provided by the deterministic delay and multi-channel synchronous trigger management module 18. The frequency selection A pin and frequency selection B pin of the LTC1068 switched-capacitor filter set the cutoff frequency of the filter through a resistor divider network.

[0034] The front-end module 17 for analog mechanical impedance analysis includes an AD734 analog multiplier / divider, an OPA2182 precision operational amplifier, and an AD8302 phase detector. The X-input pin of the AD734 analog multiplier / divider is connected to the output signal of the torque sensor 6 via a third resistor. The Y-input pin of the AD734 analog multiplier / divider is connected to the angular velocity voltage signal after the encoder signal has been processed by an analog differentiator via a fourth resistor. The output pin of the AD734 analog multiplier / divider is connected to the analog-to-digital converter input channel of the main control and calculation core module 14 via a fifth resistor. The non-inverting input of the OPA2182 precision operational amplifier is connected to the A-phase signal of the rotary encoder 11 via a sixth resistor. The inverting input of the PA2182 precision operational amplifier is connected to the B-phase signal of the rotary encoder 11 through the seventh resistor. The output of the PA2182 precision operational amplifier is connected to the Y-phase input pin of the AD734 analog multiplier / divider. The non-inverting input pin of the AD8302 phase detector is connected to the excitation signal generated by the wideband piezoelectric ceramic exciter drive circuit module 15 through the sixth coupling capacitor. The inverting input pin of the AD8302 phase detector is connected to the response signal of the high dynamic range synchronous sampling sensor signal conditioning circuit module 16 through the seventh coupling capacitor. The phase voltage output pin of the AD8302 phase detector is connected to the analog-to-digital conversion input channel of the main control and computing core module 14 through the eighth resistor.

[0035] The deterministic delay and multi-channel synchronous trigger management module 18 includes a Si5338 multi-output clock generator and a field-programmable gate array (FPGA). The clock zero positive differential output pin and clock zero negative differential output pin of the Si5338 multi-output clock generator are connected to the clock input pin of the multi-zone clock controller of the FPGA. The serial data pin and serial clock pin of the Si5338 multi-output clock generator are connected to the main control and computing core module 14. The input-output zero pin of the FPGA is connected to the synchronous trigger input terminal of the wideband piezoelectric ceramic exciter drive circuit module 15. The input-output one pin of the FPGA is connected to the sampling trigger input terminal of the high dynamic range synchronous sampling sensor signal conditioning circuit module 16. The input-output two pin of the FPGA is connected to the reset input terminal of the analog calculation mechanical impedance analysis front-end module 17. The joint test action group test clock pin, joint test action group test mode selection pin, joint test action group test data input pin, and joint test action group test data output pin of the FPGA are connected to the joint test action group interface of the main control and computing core module 14.

[0036] The embedded real-time parameter identification coprocessor module 19 includes a TMS320C6748 digital signal processor and an IC dynamic random access memory. The external memory interface data bus of the TMS320C6748 digital signal processor is connected to the general-purpose input / output pins of the programmable logic terminal of the main control and computing core module 14. The external memory interface address bus of the TMS320C6748 digital signal processor is connected to the general-purpose input / output pins of the programmable logic terminal of the main control and computing core module 14. The external memory interface chip select pin 2 of the TMS320C6748 digital signal processor, external memory interface chip select pin 2, external memory interface chip select pin 3, external memory interface chip select pin 4, external memory interface chip select pin 5, external memory interface chip select pin 6 ... The external memory interface write enable pin and external memory interface output enable pin are connected to the programmable logic general-purpose input / output pins of the main control and computing core module 14. The double data rate data bus of the TMS320C6748 digital signal processor is connected to the IC dynamic random access memory. Pins 0 to 14 of the double data rate address bus of the TMS320C6748 digital signal processor are connected to the IC dynamic random access memory. The double data rate memory area address bus of the TMS320C6748 digital signal processor is connected to the memory area address bus of the IC dynamic random access memory.

[0037] The adaptive closed-loop power and thermal management module 20 includes a negative temperature coefficient thermistor, an OPA2182 differential amplifier, a TPS7A4700 low-dropout linear regulator, an LTM4644 switching regulator, a thermoelectric cooler, and a MAX1968 thermoelectric cooler driver. The voltage input pin of the TPS7A4700 low-dropout linear regulator is connected to a 12V power supply, its voltage output pin outputs a 5V power supply, and its ground pin is grounded. The voltage input pin of the LTM4644 switching regulator is connected to a 5V power supply, and its voltage output pin outputs a 0.1V voltage. The power ground pin of the 4644 switching regulator is connected to digital ground. The negative temperature coefficient thermistor is attached to the SoC chip in the main control and computing core module 14. The negative temperature coefficient thermistor is connected to the input of the OPA2182 differential amplifier. The output of the OPA2182 differential amplifier is connected to the temperature monitoring pin of the MAX1968 thermoelectric cooler driver. The thermoelectric cooler is mounted on the main control heat sink of the SoC chip in the main control and computing core module 14. The high and low output pins of the MAX1968 thermoelectric cooler driver are connected to the thermoelectric cooler. The serial data and serial clock pins of the MAX1968 thermoelectric cooler driver are connected to the main control and computing core module 14.

[0038] The online identification circuit for the time-varying characteristics of the ball head includes the following steps during operation:

[0039] Step 1: Circuit initialization and self-calibration are performed through the adaptive closed-loop power and thermal management module 20. More specifically, the adaptive closed-loop power and thermal management module 20 performs power sequence power-on and stability detection to ensure that the voltage of each power rail reaches more than 95% of the rated voltage after the set stabilization time. The high dynamic range synchronous sampling sensor signal conditioning circuit module 16 performs sensor zero-point and full-scale calibration and calculates the zero-point offset of the torque sensor 6 under zero-load conditions. This offset is the arithmetic mean of multiple sampling data. The deterministic delay and multi-channel synchronous trigger management module 18 performs clock tree synchronization and phase alignment and calculates the clock phase difference compensation. This compensation is the difference between the measured phase and the reference phase divided by the product of the two phases and the clock frequency.

[0040] Step 2: The main control and computing core module 14 controls the wideband piezoelectric ceramic exciter drive circuit module 15 to generate a dynamic spectrum excitation signal. More specifically, the main control and computing core module 14 controls the wideband piezoelectric ceramic exciter drive circuit module 15 to generate a multi-band composite excitation signal. The amplitude of the sweep excitation signal changes with time, and the frequency changes linearly between the start frequency and the end frequency. The main control and computing core module 14 performs power spectral density shaping on the excitation signal. The shaped excitation spectrum is the product of the original excitation spectrum and the pre-equalization filter designed based on historical data.

[0041] Step 3: The deterministic delay and multi-channel synchronous triggering management module 18 coordinates the high dynamic range synchronous sampling sensor signal conditioning circuit module 16 to perform multimodal data synchronous acquisition. More specifically, the deterministic delay compensation data alignment is performed by the deterministic delay and multi-channel synchronous triggering management module 18. The corrected timestamp of each channel data is the acquisition time plus the sum of cable delay, analog-to-digital conversion delay and processing delay. The high dynamic range synchronous sampling sensor signal conditioning circuit module 16 performs anti-aliasing filtering and downsampling, using a multi-stage decimation filtering method. The output data is the convolution sum of the input data and the coefficients of the anti-aliasing finite-length unit impulse response filter.

[0042] Step 4: The mechanical impedance is calculated online by combining the front-end module 17 of the simulation calculation mechanical impedance analysis with the high dynamic range synchronous sampling sensor signal conditioning circuit module 16. More specifically, the mechanical impedance is calculated by combining the front-end module 17 of the simulation calculation mechanical impedance analysis with the high dynamic range synchronous sampling sensor signal conditioning circuit module 16. The frequency response function estimation method is used. The mechanical impedance is the ratio of the force signal self-power spectrum to the force-velocity cross-power spectrum. The coherence function quality is evaluated by the front-end module 17 of the simulation calculation mechanical impedance analysis. The coherence function is the square of the magnitude of the force-velocity cross-power spectrum divided by the product of the force signal self-power spectrum and the velocity signal self-power spectrum.

[0043] Step 5: Viscoelastic material parameters are identified through the embedded real-time parameter identification coprocessor module 19. More specifically, a generalized Kelvin-Voyt model is established through the embedded real-time parameter identification coprocessor module 19. The transfer function of this model is a complex variable function composed of the elastic modulus and a series of spring-damping units connected in parallel. Nonlinear least square parameter optimization is performed through the embedded real-time parameter identification coprocessor module 19. The optimization objective is to minimize the sum of squares of the differences between the measured mechanical impedance and the model mechanical impedance at each frequency point.

[0044] Step Six: Perform thixotropic characteristic quantitative analysis through the embedded real-time parameter identification coprocessor module 19. More specifically, establish a structural recovery dynamic model through the embedded real-time parameter identification coprocessor module 19. This model describes the rate of change of structural parameters over time as equal to the difference between the structural recovery rate and the structural failure rate. Extract transient response features through the embedded real-time parameter identification coprocessor module 19 and calculate the difference between the first-cycle starting torque and the steady-state torque as the torque decay characteristic quantity.

[0045] Step 7: Multi-feature fusion and state classification are performed through the main control and computing core module 14. More specifically, the main control and computing core module 14 constructs a time-frequency domain feature vector, which includes multiple feature parameters such as elastic modulus, viscosity coefficient, recovery time constant, torque decay feature, resonant frequency, and damping ratio. The main control and computing core module 14 performs Mahalanobis distance anomaly detection and calculates the Mahalanobis distance between the current feature vector and the mean vector of healthy samples. The main control and computing core module 14 performs failure mode discrimination based on fuzzy logic and uses the sigmoid function to calculate the membership degree of ghost failure modes.

[0046] Step 8: Adaptive detection parameter update is performed through the main control and calculation core module 14. More specifically, the detection threshold is adapted based on historical data through the main control and calculation core module 14. The new detection threshold is the product of the historical data mean plus the historical data standard deviation and the adjustment coefficient. The excitation signal parameters are optimized online through the main control and calculation core module 14. The optimal excitation amplitude is the excitation amplitude that minimizes the condition number of the mechanical impedance matrix.

[0047] Overall, when the tie rod ball head needs to be tested, the tie rod ball head is fixed by the active chuck 10 and the driven chuck. Then, the active chuck 10 is driven to rotate by the servo motor 8 through the reducer 9, so that the tie rod ball head can rotate accordingly. During this process, the torque sensor 6 detects the torque, and the ball head time-varying characteristic online identification circuit works in conjunction with it.

[0048] The adaptive closed-loop power and thermal management module 20 uses a low-dropout linear regulator and a switching regulator to establish a clean power rail, and maintains the key chip at a constant temperature of about 25°C through a thermoelectric cooler driver, effectively eliminating the impact of temperature drift on measurement accuracy and providing a stable working foundation for the entire circuit.

[0049] Next, the SoC chip in the main control and computing core module 14 initiates the circuit's self-calibration process through the collaborative processing of its PS and PL terminals. In this process, the programmable gain amplifier of the high dynamic range synchronous sampling sensor signal conditioning circuit module 16 automatically adjusts the gain setting, the analog-to-digital converter acquires the sensor zero-position signal at 24-bit resolution, calculates the zero-position offset of the torque sensor 6 and the noise floor of the acoustic emission sensor, and at the same time, the clock generator in the deterministic delay and multi-channel synchronous trigger management module 18 generates a highly stable global clock. The field-programmable gate array uses primitives to perform picosecond-level precision delay calibration on the trigger signals of each channel to ensure strict synchronization of all data acquisition channels. This initialization process restores the circuit to a known standard state, eliminating errors introduced by environmental factors and device variations.

[0050] During the excitation signal generation stage, the waveform generator chip of the broadband piezoelectric ceramic exciter drive circuit module 15 generates a composite excitation signal under the control of the SoC, including a linearly swept sine signal from 1Hz to 100Hz and a maximum-length pseudo-random binary sequence signal. These digital waveforms are transmitted to a high-voltage power operational amplifier through a coupling capacitor. The amplifier converts the weak voltage signal into a high-voltage, high-current drive signal under ±150V power supply. This signal is applied to the piezoelectric ceramic exciter 13, which is attached to the ball head, through a current sampling resistor, converting its electrical signal into a micro-amplitude mechanical vibration. This vibration is transmitted to the internal structure of the ball head through the active chuck 10. At the same time, the digital isolator ensures complete isolation between the high-voltage drive circuit and the low-voltage control circuit to prevent ground loop interference. This multi-band composite excitation can simultaneously excite various dynamic characteristics inside the ball head, including the viscoelastic response of the polymer ball cup and the structural resonance of the grease.

[0051] During the data acquisition phase, after the excitation signal is injected into the ball head circuit, the high dynamic range synchronous sampling sensor signal conditioning circuit module 16 begins to synchronously acquire multimodal response signals. The strain bridge of the torque sensor 6 outputs a small voltage signal, which is then amplified by a programmable gain amplifier, filtered for anti-aliasing by a switched capacitor filter, and finally digitized by an analog-to-digital converter at a sampling rate of 1MHz.

[0052] The charge output signal of the micro-vibration accelerometer is converted into a voltage signal by a signal conditioner and then acquired by an analog-to-digital converter.

[0053] The output signal of the acoustic emission sensor is directly input to another input channel of the analog-to-digital converter after passing through a preamplifier.

[0054] All of these acquisition processes are carried out under the unified coordination of the deterministic delay and multi-channel synchronous trigger management module 18. The field programmable gate array generates precise trigger pulses based on the encoder angle signal to ensure strict synchronization of torque, vibration and acoustic emission data.

[0055] During the signal processing and characteristic analysis stage, the analog multiplier / divider of the front-end module 17 for analog calculation of mechanical impedance analysis calculates the mechanical impedance in real time. Its X input channel receives the force signal from the torque sensor 6, and its Y input channel receives the angular velocity signal obtained by the analog differentiator from the signal from the rotary encoder 11. In the division mode, it directly outputs the analog quantity of mechanical impedance. At the same time, the phase detector measures the phase difference between the excitation and response signals. These analog calculation results are sent to the analog-to-digital converter for digitization.

[0056] The DSP chip of the embedded real-time parameter identification coprocessor module 19 receives all the digitized data, executes the generalized Kelvin-Voigt model parameter fitting algorithm, optimizes the elastic modulus and viscosity coefficient through nonlinear least squares method, and calculates the rate of change of structural parameters based on the thixotropic recovery equation, extracting the first-cycle starting torque decay characteristics and recovery time constant.

[0057] During the state determination and output phase, the main control and computing core module 14 receives feature parameters from the DSP coprocessor, constructs a feature vector containing parameters such as elastic modulus, viscosity coefficient, recovery time constant, torque decay feature, resonant frequency and damping ratio, calculates the statistical distance between the current sample and the healthy sample library using Mahalanobis distance, and uses fuzzy logic algorithm to calculate the membership degree of the "ghost failure" mode, and finally outputs the qualified / unqualified judgment according to the preset threshold.

[0058] This successfully transforms the traditional static single-point torque measurement into a comprehensive dynamic characteristic diagnosis, which can distinguish between the true creep of polymer ball cups and the pseudo failure caused by grease thixotropy. After the batch of ball heads was left to stand for 24 hours, the polymer ball cups underwent micro-creep under continuous preload, while the grease fully recovered its three-dimensional network structure, which is manifested as an abnormal decay of the initial torque in traditional tests.

[0059] This circuit, by actively applying broadband excitation and analyzing the characteristic changes in the mechanical impedance spectrum, can clearly identify the difference between the permanent decrease in stiffness caused by creep and the instantaneous structural strength caused by thixotropy. Specifically, creep mainly affects the real part of the mechanical impedance and is irreversible under continuous excitation, while thixotropy mainly affects the imaginary part of the mechanical impedance and quickly recovers to normal after the gel structure is destroyed.

[0060] Furthermore, the high-frequency stress wave unique to the fracture of the grease structure captured by the acoustic emission sensor and the specific resonant frequency shift detected by the micro-vibration accelerometer, along with the difference between the currently fitted Kelvin-Voigt model parameters and the standard health model, are further quantified by the embedded real-time parameter identification coprocessor. Finally, the main control and calculation core module 14 obtains an accurate state determination based on the multi-feature fusion algorithm, solving the problem of non-repeatability of detection results caused by the coupling of time-varying material behavior.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A static performance testing device for automotive tie rod ball joints, characterized in that, The ball head time-varying characteristic online identification circuit includes a piezoelectric ceramic exciter (13) installed on the inside of the driving chuck (10), a three-axis micro-vibration accelerometer and an acoustic emission sensor for installation on the ball head of the measured pull rod, and a master control and computing core module (14), which is connected with a wide-band piezoelectric ceramic exciter driving circuit module (15), a high-dynamic-range synchronous sampling sensor signal conditioning circuit module (16), an analog computing mechanical impedance analysis front-end module (17), a deterministic delay and multi-channel synchronous trigger management module (18), an embedded real-time parameter identification coprocessor module (19), and a self-adaptive closed-loop power and heat management module (20). The piezoelectric ceramic exciter (13) is connected with the wide-band piezoelectric ceramic exciter driving circuit module (15), the output ends of the torque sensor (6), the acoustic emission sensor, and the three-axis micro-vibration accelerometer are connected to the high-dynamic-range synchronous sampling sensor signal conditioning circuit module (16), the torque sensor (6) and the rotary encoder (11) are connected with the analog computing mechanical impedance analysis front-end module (17), the trigger signal output end of the deterministic delay and multi-channel synchronous trigger management module (18) is connected to the synchronous trigger input end of the wide-band piezoelectric ceramic exciter driving circuit module (15) and the sampling trigger input end of the high-dynamic-range synchronous sampling sensor signal conditioning circuit module (16), the deterministic delay and multi-channel synchronous trigger management module (18) is connected with the servo motor (8) through the motor encoder (12), the master control and computing core module (14) and the embedded real-time parameter identification coprocessor module (19) are connected with an upper computer through an industrial Ethernet bus, and the power output end of the self-adaptive closed-loop power and heat management module (20) provides power.

2. The static performance test device for a ball head of a tie rod of an automobile according to claim 1, characterized by, The master control and computing core module (14) includes an SoC chip, a DDR3 memory, and a Flash memory, the SoC chip is connected with the DDR3 memory and the Flash memory, and the SoC chip is connected with the interfaces of various modules through its input and output interfaces.

3. The static performance test device for a ball head of a tie rod of an automobile according to claim 2, characterized in that, ​ 4. The static performance test device for a ball head of a tie rod of an automobile according to claim 2, characterized by The wideband piezoelectric ceramic exciter drive circuit module (15) includes a waveform generator, a high-voltage power operational amplifier, and a digital isolator. The positive and negative differential output pins of the waveform generator are connected to the non-inverting input pin of the high-voltage power operational amplifier through first and second coupling capacitors. The serial clock pin, serial data input pin, and chip select pin of the waveform generator are connected to the serial peripheral interface of the main control and computing core module (14) through the digital isolator. The power supply pin of the high-voltage power operational amplifier is connected to a power source. The output pin of the high-voltage power operational amplifier is connected to the positive electrode of the piezoelectric ceramic exciter (13) through a current sampling resistor. The negative electrode of the piezoelectric ceramic exciter (13) is grounded. The sense pin of the high-voltage power operational amplifier is connected to the output pin of the high-voltage power operational amplifier through a first resistor. The negative input pin of the high-voltage power operational amplifier is grounded through a second resistor.

5. The static performance test device for a ball head of a tie rod of an automobile according to claim 2, characterized by The high-dynamic-range synchronous sampling sensing signal conditioning circuit module (16) includes a programmable gain amplifier, an AD7124-8 analog-to-digital converter, an ADS127L01 analog-to-digital converter, and an LTC1068 switched-capacitor filter. The positive voltage input pin of the programmable gain amplifier is connected to the signal output end of the torque sensor (6) through an input resistor. The voltage output pin of the programmable gain amplifier is connected to the analog input zero channel pin of the AD7124-8 analog-to-digital converter. The signal output end of the micro-vibration accelerometer is connected to the analog input two positive pin of the ADS127L01 analog-to-digital converter through a third coupling capacitor. The analog input two negative pin of the ADS127L01 analog-to-digital converter is grounded through a fourth coupling capacitor. The signal output end of the acoustic emission sensor is connected to the analog input three channel pin of the AD7124-8 analog-to-digital converter through a fifth coupling capacitor. The serial clock pin, serial data input pin, serial data output pin, and chip select pin of the AD7124-8 analog-to-digital converter are connected to the first serial peripheral interface of the main control and computing core module (14). The signal input pin of the LTC1068 switched-capacitor filter is connected to the voltage output pin of the programmable gain amplifier. The signal output pin of the LTC1068 switched-capacitor filter is connected to the analog input one channel pin of the AD7124-8 analog-to-digital converter. The clock input pin of the LTC1068 switched-capacitor filter receives a clock signal provided by the deterministic delay and multi-channel synchronous trigger management module (18). The frequency selection A pin and frequency selection B pin of the LTC1068 switched-capacitor filter set the cutoff frequency of the filter through a resistor voltage dividing network.

6. The static performance test device for a ball head of a tie rod of an automobile according to claim 2, characterized by The analog computing mechanical impedance analysis front-end module (17) comprises an AD734 analog multiplier divider, an OPA2182 precision operational amplifier and an AD8302 phase detector, the X-input pin of the AD734 analog multiplier divider is connected to the output signal of the torque sensor (6) through a third resistor, the Y-input pin of the AD734 analog multiplier divider is connected to the angular velocity voltage signal processed by the analog differentiator of the encoder signal through a fourth resistor, the output pin of the AD734 analog multiplier divider is connected to the analog-to-digital conversion input channel of the host and computing core module (14) through a fifth resistor, the non-inverting input terminal of the OPA2182 precision operational amplifier is connected to the A-phase signal of the rotary encoder (11) through a sixth resistor, the inverting input terminal of the OPA2182 precision operational amplifier is connected to the B-phase signal of the rotary encoder (11) through a seventh resistor, the output terminal of the OPA2182 precision operational amplifier is connected to the Y2-input pin of the AD734 analog multiplier divider, the non-inverting input pin of the AD8302 phase detector is connected to the excitation signal generated by the wideband piezoelectric ceramic actuator drive circuit module (15) through a sixth coupling capacitor, the inverting input pin of the AD8302 phase detector is connected to the response signal of the high-dynamic-range synchronous sampling sensing signal conditioning circuit module (16) through a seventh coupling capacitor, and the phase voltage output pin of the AD8302 phase detector is connected to the analog-to-digital conversion input channel of the host and computing core module (14) through an eighth resistor.

7. The static performance test device for a ball head of a tie rod of an automobile according to claim 2, characterized by The deterministic delay and multi-channel synchronous trigger management module (18) comprises a Si5338 multi-output clock generator and a field programmable gate array, the clock zero positive differential output pin and the clock zero negative differential output pin of the Si5338 multi-output clock generator are connected to the multi-region clock controller clock input pin of the field programmable gate array, the serial data pin and the serial clock pin of the Si5338 multi-output clock generator are connected to the host and computing core module (14), the input-output zero pin of the field programmable gate array is connected to the synchronous trigger input end of the wideband piezoelectric ceramic actuator drive circuit module (15), the input-output one pin of the field programmable gate array is connected to the sampling trigger input end of the high-dynamic-range synchronous sampling sensing signal conditioning circuit module (16), the input-output two pin of the field programmable gate array is connected to the reset input end of the analog computing mechanical impedance analysis front-end module (17), and the joint test action group test clock pin, the joint test action group test mode selection pin, the joint test action group test data input pin and the joint test action group test data output pin of the field programmable gate array are connected to the joint test action group interface of the host and computing core module (14).

8. The static performance test device for a ball head of a tie rod of an automobile according to claim 2, characterized by The embedded real-time parameter recognition coprocessor module (19) includes a TMS320C6748 digital signal processor and an IC dynamic random access memory, an external memory interface data bus of the TMS320C6748 digital signal processor is connected to a general input and output pin of a programmable logic end of the master control and computing core module (14), an external memory interface address bus of the TMS320C6748 digital signal processor is connected to a general input and output pin of a programmable logic end of the master control and computing core module (14), a chip select two pin, an external memory interface write enable pin and an external memory interface output enable pin of the TMS320C6748 digital signal processor are connected to a general input and output pin of a programmable logic end of the master control and computing core module (14), a double data rate data bus of the TMS320C6748 digital signal processor is connected to the IC dynamic random access memory, double data rate address bus zero to fourteen pins of the TMS320C6748 digital signal processor are connected to the IC dynamic random access memory, and a double data rate storage area address bus of the TMS320C6748 digital signal processor is connected to a storage area address bus of the IC dynamic random access memory.

9. The static performance test device for a ball head of a tie rod of an automobile according to claim 1, characterized by The adaptive closed-loop power and thermal management module (20) includes a negative temperature coefficient thermistor, an OPA2182 differential amplifier, a TPS7A4700 low dropout linear regulator, an LTM4644 switching regulator and a thermoelectric cooler, and a MAX1968 thermoelectric cooler driver, a voltage input pin of the TPS7A4700 low dropout linear regulator is connected to a 12V power supply, a voltage output pin of the TPS7A4700 low dropout linear regulator outputs a 5V power supply, a ground pin of the TPS7A4700 low dropout linear regulator is grounded, a voltage input pin of the LTM4644 switching regulator is connected to a 5V power supply, a voltage output pin of the LTM4644 switching regulator outputs a 0.1V voltage, a power supply ground pin of the LTM4644 switching regulator is connected to a digital ground, the negative temperature coefficient thermistor is attached to a SoC chip in the master control and computing core module (14), the negative temperature coefficient thermistor is connected to an input end of the OPA2182 differential amplifier, an output end of the OPA2182 differential amplifier is connected to a temperature monitoring pin of the MAX1968 thermoelectric cooler driver, the thermoelectric cooler is installed on a master control radiator of the SoC chip in the master control and computing core module (14), an output high pin and an output low pin of the MAX1968 thermoelectric cooler driver are connected to the thermoelectric cooler, a serial data pin and a serial clock pin of the MAX1968 thermoelectric cooler driver are connected to the master control and computing core module (14).

10. The static performance test device for a ball head of a tie rod of an automobile according to claim 1, characterized by It also includes the workbench (1), fixedly connected on the workbench (1) mounting bracket, mounted on the mounting bracket speed reducer (9), set on the workbench (1) electric slide rail (2), the servo motor (8) is fixedly connected on the mounting bracket, and the servo motor (8) and the input end of speed reducer (9) are drivingly connected, the output end of speed reducer (9) and driving chuck (10) coaxial transmission is connected, the rotating seat (4) is fixedly connected on the slide (3) of electric slide rail (2).

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