Miniaturized intelligent signal decoupling device for piezoelectric multi-dimensional force measurement system

Abstract

The present invention proposes a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system, belonging to the field of signal measurement and decoupling technology. The device comprises a plurality of piezoelectric six-dimensional force sensors, which collect six-dimensional force raw signals and output charge signals via cables; a front-end signal acquisition unit, which is used to receive the charge signals output by the plurality of piezoelectric six-dimensional force sensors in parallel, process the charge signals, and output analog signals; an intelligent data decoupling unit, which is electrically connected to the front-end signal acquisition unit, is used to receive the analog signals output by the front-end signal acquisition unit, and, through a built-in decoupling and error compensation algorithm, performs data decoupling and measurement error compensation on the six-dimensional force raw signals corresponding to the analog signals to obtain a decoupled six-dimensional force signal; wherein the intelligent data decoupling unit also provides power to the front-end signal acquisition unit. The present invention introduces an adaptive quasi-static charge leakage correction and temperature drift compensation algorithm to improve decoupling accuracy. The device is also simplified in size by eliminating signal crosstalk through a stacked PCB structure.

Description

Technical Field

[0001] The present invention relates to the technical field of signal measurement and decoupling, and in particular to a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system. Background Art

[0002] With the emergence of the concept of "embodied intelligence," the demand for multi-dimensional force sensors in robotic force feedback systems is increasing. Piezoelectric force-to-transmitter (F / T) sensors, with their strong structural rigidity, excellent measurement sensitivity, and dynamic characteristics, have gained widespread adoption. In practical deployments, the charge signal generated by a piezoelectric F / T sensor must first be converted to a standard voltage signal via a charge amplifier module, then converted to a digital signal via a signal acquisition card. The host computer then performs data decoupling to obtain the measured F / T signal.

[0003] In the application scenario of adaptive robots, the miniaturization, intelligence and scalability of the signal decoupling module of the piezoelectric six-axis force sensor are very important. At present, the signal decoupling devices suitable for piezoelectric six-axis force sensors mostly adopt the design of discrete modules, such as Jiangsu Lianneng Electronics' YE5853 multi-channel charge amplifier. This device is large in size and requires the adaptation of complex signal acquisition modules and data decoupling modules at the back end, and cannot complete the signal decoupling work alone. The 5167A multi-channel charge measurement device of Kistler of Switzerland can complete the signal decoupling of single-axis or three-dimensional force sensors, but the scalability of this device is relatively weak when facing measurement scenarios equipped with piezoelectric six-axis force sensors.

[0004] Therefore, it is very necessary to provide a miniaturized intelligent signal decoupling device suitable for piezoelectric multi-dimensional force measurement systems to improve the problem of small hardware integration of multi-channel voltage signal acquisition equipment. It not only reduces the volume of the signal acquisition equipment, but also improves the crosstalk problem of multi-channel signals, and can improve the measurement channel charge leakage and temperature drift caused by the environment, provide error estimation and compensation, and improve the sensor decoupling accuracy and long-term stability. Summary of the Invention

[0005] In view of this, the present invention proposes a miniaturized intelligent signal decoupling device suitable for piezoelectric multi-dimensional force measurement system, which introduces an adaptive quasi-static charge leakage correction and temperature drift compensation algorithm to improve the decoupling accuracy.

[0006] The present invention provides a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system, comprising:

[0007] Several piezoelectric six-dimensional force sensors collect six-dimensional force raw signals and output charge signals through cables;

[0008] The front-end signal acquisition unit is used to receive the charge signals output by several piezoelectric six-dimensional force sensors in parallel, process the charge signals, and output analog signals.

[0009] The intelligent data decoupling unit is electrically connected to the front-end signal acquisition unit, and is used to receive the analog signal output by the front-end signal acquisition unit, and perform data decoupling and measurement error compensation on the six-dimensional force original signal corresponding to the analog signal through the built-in decoupling and error compensation algorithm to obtain a decoupled six-dimensional force signal;

[0010] Among them, the intelligent data decoupling unit also provides power to the front-end signal acquisition unit.

[0011] Based on the above technical solution, preferably, the front-end signal acquisition unit includes several input channels and several charge signal processing modules, and the several charge signal processing modules are electrically connected to several piezoelectric six-dimensional force sensors through the input channels in a one-to-one correspondence, and are used to independently process the six-dimensional force original signal received by each input channel.

[0012] Preferably, several charge signal processing modules all include a precision charge amplifier circuit, a programmable voltage gain circuit, an active low-pass filter circuit, a DC bias and reference voltage generating circuit and an internal temperature compensation circuit; wherein, the precision charge amplifier circuit is used to convert the charge signal corresponding to the input six-dimensional force original signal into a primary voltage signal, and the converted primary voltage signal is sent to the programmable voltage gain circuit, and the programmable voltage gain circuit converts the primary voltage signal to obtain a voltage signal after programmable gain; the active low-pass filter circuit receives the voltage signal after programmable gain, filters the voltage signal after programmable gain, and obtains a denoised voltage signal which is sent to the DC bias and reference voltage generating circuit, and the DC bias and reference voltage generating circuit adds a DC bias to the denoised voltage signal to obtain an analog signal that meets the input range of the intelligent data decoupling unit; the internal temperature compensation circuit is respectively for the self-stabilization of the ambient temperature during the power-on process of several charge signal processing modules and the constant temperature control during the online measurement process.

[0013] Further preferably, the precision charge amplifier circuit includes an electrometer operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a charge discharge analog switch SW1, one end of the first resistor R1 is electrically connected to the non-inverting input terminal of the electrometer operational amplifier U1, the other end of the first resistor R1 is grounded, the inverting input terminal of the electrometer operational amplifier U1 is electrically connected to one end of the second resistor R2, one end of the third resistor R3, one end of the first capacitor C1, and the normally open contact of the charge discharge analog switch SW1, respectively, the other end of the second resistor R2 is electrically connected to the output terminal of a piezoelectric six-axis force sensor through an input channel, the other end of the third resistor R3, the other end of the first capacitor R1, and the normally open contact of the charge discharge analog switch SW1 are all electrically connected to the output terminal of the electrometer operational amplifier U1, after the coil of the charge discharge analog switch SW1 is energized, the normally open contact of the charge discharge analog switch SW1 is closed and grounded; the precision charge amplifier circuit converts the charge signal sent by the second resistor R2 into a primary voltage signal and outputs it to the programmable voltage gain circuit;

[0014] The programmable voltage gain circuit includes a programmable gain amplifier U2, wherein the non-inverting input terminal of the programmable gain amplifier U2 is electrically connected to the output terminal of the electrometer operational amplifier U1, the inverting input terminal of the programmable gain amplifier U2 is grounded, and the programmable terminal of the programmable gain amplifier U2 is communicatively connected to the intelligent data decoupling unit; the output terminal of the programmable gain amplifier U2 is electrically connected to the input terminal of the active low-pass filter circuit;

[0015] The active low-pass filter circuit includes two groups of low-pass filter modules connected in series, each low-pass filter module includes an active amplifier U3, a fourth resistor R4, a fifth resistor R5, a second capacitor C2 and a third capacitor C3, the non-inverting input terminal of the active amplifier U3 is electrically connected to one end of the fifth resistor R5 and one end of the third capacitor C3 respectively, the other end of the third capacitor C3 is grounded, the other end of the fifth resistor R5 is electrically connected to one end of the second capacitor C2 and one end of the fourth resistor R4 respectively, the other end of the second capacitor C2 and the inverting input terminal of the active amplifier U3 are both electrically connected to the output terminal of the active amplifier U3, the other end of the fourth resistor R4 of the front-stage low-pass filter module is electrically connected to the output terminal of the programmable gain amplifier U2 as the input terminal of the active low-pass filter circuit, the output of the active amplifier U3 of the front-stage low-pass filter module serves as the input of the rear-stage low-pass filter module, and the output of the active amplifier of the rear-stage low-pass filter module serves as the output of the active low-pass filter circuit;

[0016] The DC bias and reference voltage generating circuit includes a precision amplifier U4, a voltage reference chip U5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. The input end of the voltage reference chip U5 is electrically connected to the external power input, one end of the ninth resistor R9 is electrically connected to the output end of the voltage reference chip U5, the other end of the ninth resistor R9 is electrically connected to one end of the eighth resistor R8, the power input end of the programmable gain amplifier U2, the power input end of the internal temperature compensation circuit and the input of the precision amplifier U4, respectively, and the other end of the eighth resistor R8 is grounded; the input end of the precision amplifier U4 is also electrically connected to the output end of the active low-pass filter circuit, the inverting input end of the precision amplifier U4 is electrically connected to one end of the sixth resistor R6 and one end of the seventh resistor R7, the other end of the sixth resistor R6 is grounded, and the other end of the seventh resistor R7 is electrically connected to the output end of the precision amplifier U4. The output end of the precision amplifier U4 outputs an analog signal that meets the input range of the intelligent data decoupling unit;

[0017] The internal temperature compensation circuit includes a power drive unit and a heating power resistor array. The power drive unit adopts a totem pole push-pull output structure based on an NMOS tube to provide an input signal for the heating power resistor array; the heating power resistor array is arranged one-to-one in several charge signal processing modules; the heating drive signal input end of the power drive unit is electrically connected to the intelligent data decoupling unit.

[0018] Further preferably, the intelligent data decoupling unit includes a main controller, a human-computer interaction module, an onboard power supply and a communication module; the main controller is connected to the human-computer interaction module and the communication module, and the main controller has a built-in decoupling and error compensation algorithm for receiving the analog signal output by the front-end signal acquisition unit, performing data decoupling and measurement error compensation on the analog signal, obtaining the decoupled six-dimensional force signal and sending it to the human-computer interaction module and the communication module respectively; the onboard power supply supplies power to the main controller and the human-computer interaction module, and serves as an external power input for several charge signal processing modules; the human-computer interaction module is used to output and display the decoupled six-dimensional force signal; the communication module is used for parameter configuration, equipment debugging, or transmitting the decoupled six-dimensional force signal to the host computer or Internet of Things device in real time.

[0019] Further preferably, the decoupling and measurement error compensation algorithm includes the following:

[0020] S1: The main controller is equipped with an ADC module, and the input channels of the ADC module are set in a one-to-one correspondence with the output terminals of several charge signal processing modules; the main controller adjusts the gain level of the programmable voltage gain circuit to determine the range of the voltage signal after the programmable gain;

[0021] S2: The main controller uses the M-order FIR bandpass filter algorithm based on the Hanning window function to denoise the input analog signal and obtain the original voltage signal U n And stored in the FIFO buffer queue of the main controller, the original voltage signal U that meets the voltage range of the analog signal n Extract and compensate the gain of the original voltage signal input by each input channel of the ADC module: U 1×n =G 1×n U n , n=6,7,8,G 1×n is the gain compensation, and is the original voltage signal U after gain compensation 1×n Then, according to the charge mapping relationship of each channel, the six-dimensional charge accumulation integral U linearly related to each force is calculated. FT :U FT =[U Fx , U Fy , U Fz , U Mx , U Mx , U Mx ]=U 1×n I n×6 , U Fx , U Fy , U Fz , U Mx , U Mx , U Mx is the six-dimensional charge cumulative integral, I n×6 is the channel mapping matrix;

[0022] S3: Piezoelectric conversion gain coefficient vector A of the piezoelectric six-axis force sensor calibrated using the linear regression method 1×6 and the bias coefficient vector b 1×6 :FT 1×6 =A 1×6 U FT +b 1×6 , FT 1×6 The six-dimensional force raw signal measurement data for preliminary decoupling;

[0023] S4: Perform secondary decoupling on the initially decoupled six-axis force original signal measurement data, calibrate the multi-axis coupling error of the piezoelectric six-axis force sensor based on the least squares method, and use the decoupling coefficient matrix obtained by optimal estimation Solve the precise measurement result FT of the six-dimensional force original signal of the piezoelectric six-dimensional force sensor d :FT d =D 6×6 FT 1×6 ,in D 6×6 is the decoupling coefficient matrix, is the actual measurement value of the axial calibration test;

[0024] S5: The measurement error compensation algorithm includes quasi-static charge leakage correction and temperature drift compensation. Quasi-static charge leakage correction uses the charge discharge analog switch SW1 in the precision charge amplifier circuit. After the front-end signal acquisition unit completes initialization and starts the measurement task, it first performs a charge discharge reset operation and continuously collects the static charge signals U of several piezoelectric six-axis force sensors for a period of time. Raw , record the current ambient temperature T, and when the effective data volume reaches the set threshold, perform linear fitting on the charge leakage coefficients corresponding to several input channels to obtain the charge leakage rate v under the current ambient temperature parameters N and the quasi-static charge bias s N (T), the main controller calculates the real-time compensation charge measurement result U through the following formula N :U N =v N U Raw +s N (T), N=[1, 2,..., n];

[0025] Temperature drift compensation uses the internal temperature compensation circuit and the current ambient temperature T. After the front-end signal acquisition unit is powered on, the output power of the heating power resistor array is adjusted through a proportional regulation method according to the set temperature holding threshold so that the front-end signal acquisition unit reaches the set operating temperature. The main controller adjusts the duty cycle of the heating drive signal of the power drive unit according to the deviation between the calculated temperature measurement value and the set temperature holding threshold to keep the operating temperature of the front-end signal acquisition unit constant.

[0026] S6: The main controller corrects the calculated real-time compensation charge measurement result to compensate for the quasi-static charge leakage and temperature drift, and saves the compensation amount at the current temperature in the main controller.

[0027] Further preferably, the main controller described in step S1 adjusts the gain gear of the programmable voltage gain circuit to determine the range of the voltage signal after the programmable gain, and determines the range of the voltage signal after the programmable gain by a double threshold method; first, the starting range of the voltage signal after the programmable gain is set, and the ADC module of the main controller collects the analog signal corresponding to the output of the current piezoelectric six-dimensional force sensor, and uses the sliding window method to filter the voltage data within the holding time range to obtain the average reference value of the voltage measurement result of the current analog signal, set the voltage upper and lower threshold parameters and, and compare with the measured value, let the voltage upper threshold parameter of the current range be V upper , the voltage lower threshold parameter of the current range is V lower The voltage upper and lower threshold parameters are V th =V lower +V upper, the current measured value is V measured , the main controller determines the current optimal gain gear through the following discriminant: Where δ is the allowable deviation, which shall not exceed 1% of the sum of the upper and lower threshold parameters of the current range voltage.

[0028] Further preferably, the main controller in step S2 uses an M-order FIR bandpass filtering algorithm based on a Hanning window function to denoise the input analog signal, including the following contents: defining the impulse response h of an ideal low-pass filter LP (m): where f c is the cutoff frequency, f s is the sampling frequency, M is the filter order, m=0, 1, 2, ..., M, x is the variable in the brackets; let the lower cutoff frequency of the FIR bandpass be f1 and the upper cutoff frequency of the FIR bandpass be f2, then the impulse response function of the FIR bandpass is Multiply each point by the window function w(n) to suppress frequency leakage in the FIR process: h(m) = h BP (m)·w(n), The frequency response function of the M-order FIR bandpass filter algorithm based on the Hanning window function is:

[0029] Further preferably, the onboard power supply obtains a 5V power rail through a DC regulated power supply, an adapter input or a USB interface, the 5V power supply is stepped down to obtain a 3.3V power rail for use by the main controller, and the 5V power supply is stepped up and reversed to obtain a +12V power rail and a -12V power rail for use by several charge signal processing modules.

[0030] Further preferably, it also includes a box, the main controller and onboard power supply of the intelligent data decoupling unit are integrated on the first PCB circuit board, and the first PCB circuit board is arranged in the middle position of the box; a number of charge signal processing modules are respectively integrated on the second PCB circuit board and the third PCB circuit board, and the second PCB circuit board and the third PCB circuit board are respectively fixedly arranged in the box on both sides of the first PCB circuit board, and the human-computer interaction module and the communication module are embedded in different surfaces of the box; a number of input channels are respectively provided on the second PCB circuit board and the third PCB circuit board, and the input channels are used to electrically connect with a number of piezoelectric six-dimensional force sensors in a one-to-one correspondence; shielding covers are provided on both sides of the second PCB circuit board and the third PCB circuit board; adjacent PCB circuit boards are fixed and spaced apart by copper pillars.

[0031] The present invention provides a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system, which has the following advantages over the prior art:

[0032] (1) The present invention proposes a miniaturized hardware integration solution for a multi-channel piezoelectric signal acquisition unit. This solution adopts a charge signal processing solution based on active feedback amplification. Furthermore, through a stacked PCB layout and an external shielding structure, the structure volume of the multi-channel piezoelectric signal acquisition unit is reduced while improving the crosstalk problem of the multi-channel signals.

[0033] (2) The device implements software and hardware solutions for quasi-static charge leakage correction and temperature drift compensation of piezoelectric six-axis force sensors under different environments. The miniaturization of the signal decoupling unit will inevitably affect the measurement accuracy and stability of the device, so it is necessary to additionally consider the charge leakage and temperature drift of the measurement channel caused by the environment. In the present invention, the intelligent data decoupling unit is equipped with an adaptive quasi-static charge leakage correction and temperature drift compensation algorithm. During the initialization of the device, after obtaining the piezoelectric signal of the six-axis force sensor measured in each channel, the algorithm uses a digital FIR bandpass filter to denoise the original voltage signal, and performs F / T signal decoupling and error compensation on the multi-channel voltage signal output by the charge signal processing module, effectively improving the F / T decoupling accuracy and long-term stability of the piezoelectric six-axis force sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 This is a hardware structure block diagram of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0036] Figure 2 This is a circuit diagram of a charge signal processing module of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0037] Figure 3 This is a structural block diagram of an intelligent data decoupling unit of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0038] Figure 4 This is a structural block diagram of an onboard power supply of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0039] Figure 5 This is a three-dimensional diagram of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention after being packaged in a box;

[0040] Figure 6 This is a schematic diagram of the PCB stacking structure of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0041] Figure 7 This is a program operation flow chart of a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0042] Figure 8 This is a flow chart of a quasi-static charge leakage correction and temperature drift compensation algorithm for a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to the present invention;

[0043] Figure 9 This is a flow chart of a multi-channel piezoelectric signal decoupling algorithm for a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system of the present invention.

[0044] Figure numerals: 1. Status indicator light; 2. LCD display screen; 3. Upper shell of the box; 4. USB-C communication interface; 5. CAN bus interface; 6. Lower shell of the box; 7. Piezoelectric six-axis force sensor output interface; 8. Second PCB circuit board; 9. Third PCB circuit board; 10. First PCB circuit board; 11. XT30DC power supply interface; 12. RS422 bus interface; 13. Precision charge amplifier circuit, programmable voltage gain circuit and its shielding cover; 14. Active low-pass filter circuit, DC bias and reference voltage generation circuit, internal temperature compensation circuit and its shielding cover; 15. Bottom shielding cover; 16. Direct-insert signal connector between PCB boards. DETAILED DESCRIPTION

[0045] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] The piezoelectric six-dimensional force sensor in the robot's force feedback system is deployed in industrial robotic arms, humanoid robots, external force perception, and force / torque (F / T) measurement and analysis of small actuators. However, the device is large in size, has poor scalability, and has problems with charge leakage and temperature drift in the measurement channel. In view of this, Figure 1 As shown, the present invention provides a miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system, comprising:

[0047] Several piezoelectric six-dimensional force sensors are used to collect six-dimensional force raw signals and output charge signals through cables; 6-8 channels of charge signals can be formed, and the charge signals can be sent to the front-end signal acquisition unit through the SMA signal terminals of the high-resistance cables.

[0048] The front-end signal acquisition unit is used to receive the charge signals output by several piezoelectric six-dimensional force sensors in parallel, process the charge signals, and output analog signals.

[0049] The intelligent data decoupling unit is electrically connected to the front-end signal acquisition unit, and is used to receive the analog signal output by the front-end signal acquisition unit, perform ADC conversion on the analog signal, and perform data decoupling and measurement error compensation on the six-dimensional force original signal corresponding to the analog signal through the built-in decoupling and error compensation algorithm to obtain a decoupled six-dimensional force signal;

[0050] The intelligent data decoupling unit also provides power management, communication functions, and control signal input to the front-end signal acquisition unit. The intelligent data decoupling unit transmits the acquired piezoelectric six-dimensional force to a host computer or IoT device, and provides real-time feedback on the device's measurement parameters and operating status through a human-computer interface.

[0051] Depend on Figure 1 The device integrates a multi-channel signal acquisition unit and an intelligent data decoupling unit, enabling multi-channel piezoelectric signal measurement and F / T data decoupling for piezoelectric six-axis force sensors of various structures. In terms of hardware, the device is equipped with an 8-channel miniaturized intelligent data decoupling unit, integrated with a high-performance processor and various peripheral modules, enabling voltage signal acquisition, six-axis force data decoupling, and error compensation. Furthermore, the device is equipped with a programmable digital communication interface and a human-computer interaction unit, enhancing the scalability and usability of the signal decoupling device.

[0052] like Figure 1 As shown, the front-end signal acquisition unit includes several input channels and several charge signal processing modules. The charge signal processing modules are electrically connected to several piezoelectric six-axis force sensors through the input channels, one-to-one, to independently process the six-axis force raw signals received by each input channel. The front-end signal acquisition unit shown in the figure has up to eight input channels, namely CH1, CH2, ..., CH8. The number of channels here is only illustrative and can actually be expanded to a larger number. The number of channels shown in the figure should not be considered a limitation of the technical solution.

[0053] Further Figure 2As shown, several charge signal processing modules all include a precision charge amplifier circuit, a programmable voltage gain circuit, an active low-pass filter circuit, a DC bias and reference voltage generating circuit and an internal temperature compensation circuit; wherein, the precision charge amplifier circuit is used to convert the charge signal corresponding to the input six-dimensional force original signal into a primary voltage signal, and the converted primary voltage signal is sent to the programmable voltage gain circuit, and the programmable voltage gain circuit converts the primary voltage signal to obtain a voltage signal after programmable gain; the active low-pass filter circuit receives the voltage signal after programmable gain, filters the voltage signal after programmable gain, and obtains a denoised voltage signal which is sent to the DC bias and reference voltage generating circuit, and the DC bias and reference voltage generating circuit adds a DC bias to the denoised voltage signal to obtain an analog signal that meets the input range of the intelligent data decoupling unit; the internal temperature compensation circuit is respectively for the ambient temperature self-stabilization during the power-on process of several charge signal processing modules and the constant temperature control during the online measurement process.

[0054] Combine Figure 2 , each circuit structure and function of the charge signal processing module is explained one by one:

[0055] 1) The precision charge amplifier circuit includes an electrometer operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a charge discharge analog switch SW1. One end of the first resistor R1 is electrically connected to the non-inverting input of the electrometer operational amplifier U1, and the other end of the first resistor R1 is grounded. The inverting input of the electrometer operational amplifier U1 is electrically connected to one end of the second resistor R2, one end of the third resistor R3, one end of the first capacitor C1, and a normally open contact of the charge discharge analog switch SW1, respectively. The other end of the second resistor R2 is electrically connected to the output of a piezoelectric six-axis force sensor through an input channel. The other end of the third resistor R3, the other end of the first capacitor R1, and the normally open contact of the charge discharge analog switch SW1 are all electrically connected to the output of the electrometer operational amplifier U1. When the coil of the charge discharge analog switch SW1 is energized, the normally open contact of the charge discharge analog switch SW1 is closed and grounded. The precision charge amplifier circuit converts the charge signal input from the second resistor R2 into a primary voltage signal and outputs it to the programmable voltage gain circuit.

[0056] In this embodiment, the electrometer operational amplifier U1 uses the Analog Devices ADA4530-1, which has a leakage current of less than 20fA, effectively reducing input charge leakage during quasi-static measurements. The feedback loop of the electrometer operational amplifier U1 consists of a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The second resistor R2 is an input impedance matching resistor. The first resistor R1 and the first capacitor C1 form a charge integration loop. The first capacitor C1 is a C0G ceramic capacitor with high insulation resistance and zero temperature drift coefficient, with a capacitance of 100nF. The third resistor R3 is a gain matching resistor used to improve the low-frequency characteristics of the electrometer operational amplifier U1, and its resistance should be greater than 1GΩ. The first resistor R1 is the input balancing resistor of the electrometer operational amplifier U1, used to reduce input bias current. The charge discharge analog switch SW1 uses a wide-bandwidth TQ2SA small-signal relay, which can be externally controlled to achieve active charge discharge of the piezoelectric input channel. In terms of PCB layout, the precision charge amplifier circuit arranges signal ground loop protection rings on the input pins on both sides of the charge amplifier to reduce the coupling of environmental electrical noise; at the same time, the solder mask layer of the high-resistance charge input signal line is opened to reduce the influence of bypass parasitic capacitance.

[0057] 2) The programmable voltage gain circuit includes a programmable gain amplifier U2, the non-inverting input terminal of the programmable gain amplifier U2 is electrically connected to the output terminal of the electrometer operational amplifier U1, the inverting input terminal of the programmable gain amplifier U2 is grounded, and the programmable terminal of the programmable gain amplifier U2 is communicatively connected to the intelligent data decoupling unit; the output terminal of the programmable gain amplifier U2 is electrically connected to the input terminal of the active low-pass filter circuit.

[0058] In this embodiment, the programmable gain amplifier U2 uses the Texas Instruments PGA113, which has binary gains of 1, 2, 4, 8, 16, 32, and 128, and range gains of 1, 2, 5, 10, 20, 50, 100, and 200. The programmable gain amplifier U2 communicates with the intelligent data decoupling unit via its built-in SPI interface, allowing for dynamic adjustment of the gain multiple.

[0059] 3) The active low-pass filter circuit includes two groups of low-pass filter modules connected in series, each low-pass filter module includes an active amplifier U3, a fourth resistor R4, a fifth resistor R5, a second capacitor C2 and a third capacitor C3, the non-inverting input terminal of the active amplifier U3 is electrically connected to one end of the fifth resistor R5 and one end of the third capacitor C3, respectively, the other end of the third capacitor C3 is grounded, the other end of the fifth resistor R5 is electrically connected to one end of the second capacitor C2 and one end of the fourth resistor R4, respectively, the other end of the second capacitor C2 and the inverting input terminal of the active amplifier U3 are both electrically connected to the output terminal of the active amplifier U3, the other end of the fourth resistor R4 of the front-stage low-pass filter module is electrically connected to the output terminal of the programmable gain amplifier U2 as the input terminal of the active low-pass filter circuit, the output of the active amplifier U3 of the front-stage low-pass filter module serves as the input of the rear-stage low-pass filter module, and the output of the active amplifier of the rear-stage low-pass filter module serves as the output of the active low-pass filter circuit.

[0060] The low-pass filter module of this embodiment adopts a fourth-order Sallen-Key low-pass filter topology, and the active amplifier U3 adopts the OPA1688 low-noise precision amplifier. Its cutoff frequency is determined by the impedance network composed of the second capacitor C2, the third capacitor C3, the fourth resistor R4 and the fifth resistor R5. The cutoff frequency determined in this embodiment is 2.5kHz, which can maintain a good denoising effect while reducing the effective dynamic signal attenuation.

[0061] 4) The DC bias and reference voltage generating circuit includes a precision amplifier U4, a voltage reference chip U5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. The input end of the voltage reference chip U5 is electrically connected to the external power input, one end of the ninth resistor R9 is electrically connected to the output end of the voltage reference chip U5, the other end of the ninth resistor R9 is electrically connected to one end of the eighth resistor R8, the power input end of the programmable gain amplifier U2, the power input end of the internal temperature compensation circuit and the input of the precision amplifier U4, and the other end of the eighth resistor R8 is grounded; the input end of the precision amplifier U4 is also electrically connected to the output end of the active low-pass filter circuit, the inverting input end of the precision amplifier U4 is electrically connected to one end of the sixth resistor R6 and one end of the seventh resistor R7, the other end of the sixth resistor R6 is grounded, and the other end of the seventh resistor R7 is electrically connected to the output end of the precision amplifier U4. The output end of the precision amplifier U4 outputs an analog signal that meets the input range of the intelligent data decoupling unit.

[0062] In this embodiment, a stable DC bias signal is added to the de-noised voltage signal through a DC bias and reference voltage generation circuit, and the output is an analog signal that meets the input range of the intelligent data decoupling unit. The precision amplifier U4 is a non-inverting adder composed of a GS8552. The sixth resistor R6 and the seventh resistor R7 are used to compensate for the fixed gain error of the voltage signal. The voltage reference chip U5 uses a REF5025 voltage reference chip that includes an ambient temperature signal output. The eighth resistor R8 and the ninth resistor R9 are set to 2kΩ and 3.3kΩ, respectively, and output a reference voltage of approximately 1.55V. This is used to provide a high-PSRR DC bias voltage input for the programmable gain amplifier U2 and the precision amplifier U4, thereby meeting the static reference point of the operational amplifier under single-supply conditions.

[0063] 5) The internal temperature compensation circuit includes a power drive unit and a heating power resistor array. The power drive unit adopts a totem pole push-pull output structure based on NMOS tubes to provide input signals for the heating power resistor array; the heating power resistor arrays are arranged one-to-one at several charge signal processing modules; the heating drive signal input end of the power drive unit is electrically connected to the intelligent data decoupling unit. The totem pole push-pull output structure based on NMOS tubes is a common technical means in this field and will not be described in detail here. The heating power resistor array is composed of precision resistors with good consistency in series / parallel connection, so that the heat generated by the resistors arranged in this way is relatively uniform.

[0064] like Figure 3 As shown, the intelligent data decoupling unit includes a main controller, a human-computer interaction module, an onboard power supply and a communication module; the main controller is connected to the human-computer interaction module and the communication module, and the main controller has a built-in decoupling and error compensation algorithm for receiving the analog signal output by the front-end signal acquisition unit, performing data decoupling and measurement error compensation on the analog signal, obtaining the decoupled six-dimensional force signal and sending it to the human-computer interaction module and the communication module respectively; the onboard power supply supplies power to the main controller and the human-computer interaction module, and serves as the external power input for several charge signal processing modules; the human-computer interaction module is used to output and display the decoupled six-dimensional force signal; the communication module is used for parameter configuration, equipment debugging or transmitting the decoupled six-dimensional force signal to the host computer or Internet of Things device in real time.

[0065] In this embodiment, the main controller adopts a high-performance 32-bit STM32H743 microcontroller chip, which runs at a main frequency of 480MHz and supports a double-precision floating-point DSP operation library, which can meet the computing power requirements of multi-channel charge data decoupling and error compensation algorithm real-time deployment. At the same time, it contains a 16-bit precision SAR high-speed ADC module, supports hardware oversampling and DMA transfer functions, and is equipped with peripheral interfaces for data communication buses such as SPI, I2C, and USART, which can support complex data and control bus connections in the front-end signal acquisition unit. In terms of storage peripherals, the main controller is equipped with 32MB of RAM and ROM memory respectively, of which RAM uses a DDR chip IS42S32800, which is connected to the STM32 microcontroller via an FMC parallel bus; ROM memory uses a NOR Flash chip W25Q256, which is connected to the microcontroller via a QSPI bus.

[0066] The intelligent data decoupling unit has three independent external serial communication interfaces. The CAN and USB-C interfaces are connected to the PHY unit within the main controller, respectively. The RS422 interface uses the SIT3088E chip for level conversion and connects to the main controller's USART_TX / RX peripheral interfaces. The USB-C communication interface is dedicated to parameter configuration and firmware debugging of the main controller, while the RS422 and CAN bus interfaces are used for initial configuration of the intelligent data decoupling unit and real-time transmission of decoupled data from the six-axis force sensor. The human-machine interface module consists of two sets of LED status indicators, a 2.5-inch LCD display, and a buzzer. It is automatically controlled by the main controller via GPIO and I2C / SPI buses. An onboard power supply provides power to the front-end signal acquisition unit via the signal connector. The analog multi-channel raw voltage and temperature measurement signals output by the front-end signal acquisition unit are input into the internal ADC module pins of the main controller, and the REF3030 voltage reference chip is used to provide a low-noise voltage reference for the ADC; its charge discharge control signal and heating PWM drive signal are provided by the GPIO digital interface of the main controller, while the voltage gain status signal is read by the SPI bus through polling by setting the chip select (CS) level, and the main controller performs dual-threshold automatic gain control to select the appropriate gain multiple for the programmable gain amplifier U2.

[0067] like Figure 4 As shown in the figure, the onboard power supply obtains a 5V power rail through a DC regulated power supply, adapter input or USB interface. The 5V power supply is stepped down to obtain a 3.3V power rail for the main controller. The 5V power supply is stepped up and reversed to obtain a +12V power rail and a -12V power rail for several charge signal processing modules.

[0068] The design supports two different input power sources: a DC regulated power supply or adapter input, supporting a wide input voltage range of 6-16V. It uses the TPS54560 switching step-down chip to output a 5V power rail for the device's main system. The second is a standard USB 5V@1A input, which uses the TPD3S044 chip for ESD and overcurrent protection of the USB port and also inputs a 5V voltage rail. The two parallel 5V power supply branches are combined through a series Schottky diode to prevent power backflow. Afterwards, the 5V power rail outputs a 3.3V voltage rail through the SY8089 switching step-down chip, which is used to power the main controller and its peripherals. At the same time, it is bypassed through the LM27313 switching boost chip to output a 15V DC voltage, and uses the ICL7662 reverse voltage charge pump chip to output a -15V DC voltage. Finally, the low-noise LM317 / 337 linear voltage regulator chipset outputs +12V and -12V power rails for powering the analog path of the front-end signal acquisition unit, thereby meeting the power supply requirements of chips with different voltage levels.

[0069] The main controller's built-in decoupling and error compensation algorithms include the following:

[0070] S1: If Figure 9 The decoupling algorithm process is shown in the figure. The main controller is equipped with an ADC module, whose input channels correspond to the output terminals of several charge signal processing modules. The main controller adjusts the gain level of the programmable voltage gain circuit to determine the range of the voltage signal after programmable gain.

[0071] The main controller described in step S1 adjusts the gain gear of the programmable voltage gain circuit to determine the range of the voltage signal after the programmable gain, and determines the range of the voltage signal after the programmable gain by a double threshold method; first, the starting range of the voltage signal after the programmable gain is set, and the ADC module of the main controller collects the analog signal corresponding to the output of the current piezoelectric six-dimensional force sensor, and uses the sliding window method to filter the voltage data within the holding time range to obtain the average reference value of the voltage measurement result of the current analog signal, set the voltage upper and lower threshold parameters and, and compare them with the measured value, let the voltage upper threshold parameter of the current range be V upper , the voltage lower threshold parameter of the current range is V lower The voltage upper and lower threshold parameters are V th =V lower +V upper , the current measured value is V measured , the main controller determines the current optimal gain gear through the following discriminant: Where δ is the allowable deviation, which shall not exceed 1% of the sum of the upper and lower threshold parameters of the current range voltage.

[0072] S2: The main controller uses the M-order FIR bandpass filter algorithm based on the Hanning window function to denoise the input analog signal and obtain the original voltage signal U n And stored in the FIFO buffer queue of the main controller, the original voltage signal U that meets the voltage range of the analog signal n Extract and compensate the gain of the original voltage signal input by each input channel of the ADC module: U 1×n =G 1×n U n , n=6,7,8,G l×n is the gain compensation, and is the original voltage signal U after gain compensation l×n Then, according to the charge mapping relationship of each channel, the six-dimensional charge accumulation integral U linearly related to each force is calculated. FT :U FT =[U Fx ,U Fy ,U Fz ,U Mx ,U Mx ,U Mx ]=U l×n I n×6 , U Fx ,U Fy ,U Fz ,U Mx ,U Mx ,U Mx is the six-dimensional charge accumulation integral, I n×6 is the channel mapping matrix.

[0073] The main controller in step S2 uses an M-order FIR bandpass filtering algorithm based on a Hanning window function to denoise the input analog signal, including the following: defining the impulse response h of an ideal low-pass filter LP (m): where f c is the cutoff frequency, f s is the sampling frequency, M is the filter order, m=0,1,2,...,M, x is the variable in the brackets; let the lower cutoff frequency of the FIR bandpass be f1 and the upper cutoff frequency of the FIR bandpass be f2, then the impulse response function of the FIR bandpass is Multiply each point by the window function w(n) to suppress frequency leakage in the FIR process: h(m) = h BP (m)·w(n), The frequency response function of the M-order FIR bandpass filter algorithm based on the Hanning window function is:

[0074] S3: Piezoelectric conversion gain coefficient vector A of the piezoelectric six-axis force sensor calibrated using the linear regression method1×6 and the bias coefficient vector b 1×6 :FT 1×6 =A 1×6 U FT +b 1×6 , FT 1×6 This is the measurement data of the initial decoupled six-dimensional force raw signal.

[0075] S4: Perform secondary decoupling on the initially decoupled six-axis force original signal measurement data, calibrate the multi-axis coupling error of the piezoelectric six-axis force sensor based on the least squares method, and use the decoupling coefficient matrix obtained by optimal estimation Solve the precise measurement result FT of the six-dimensional force original signal of the piezoelectric six-dimensional force sensor d :FT d =D 6×6 FT 1×6 ,in D 6×6 is the decoupling coefficient matrix, is the actual measurement value of the axial calibration test.

[0076] S5: If Figure 8 As shown in Figure 1, the measurement error compensation algorithm includes quasi-static charge leakage correction and temperature drift compensation. Quasi-static charge leakage correction uses the charge discharge analog switch SW1 in the precision charge amplifier circuit. After the front-end signal acquisition unit completes initialization and starts the measurement task, it first performs a charge discharge reset operation and continuously collects the static charge signals U of several piezoelectric six-axis force sensors for a period of time. Raw , record the current ambient temperature T, and when the effective data volume reaches the set threshold, perform linear fitting on the charge leakage coefficients corresponding to several input channels to obtain the charge leakage rate v under the current ambient temperature parameters N and the quasi-static charge bias s N (T), the main controller calculates the real-time compensation charge measurement result U through the following formula N :U N =v N U Raw +s N (T), N = [1, 2, ..., n];

[0077] Temperature drift compensation uses the internal temperature compensation circuit and the current ambient temperature T. After the front-end signal acquisition unit is powered on, the output power of the heating power resistor array is adjusted through a proportional adjustment method according to the set temperature maintenance threshold so that the front-end signal acquisition unit reaches the set operating temperature. The main controller adjusts the duty cycle of the heating drive signal of the power drive unit according to the deviation between the calculated temperature measurement value and the set temperature maintenance threshold to keep the operating temperature of the front-end signal acquisition unit constant.

[0078] S6: The main controller corrects the calculated real-time compensation charge measurement result to compensate for the quasi-static charge leakage and temperature drift, and saves the compensation amount at the current temperature in the main controller.

[0079] The main program operation process of the intelligent data decoupling unit is as follows: Figure 7 As shown in the figure, after the device is powered on, the data decoupling unit begins initialization, waiting for the input signals from each sensor channel to stabilize and completing quasi-static charge leakage correction and temperature drift compensation for the raw piezoelectric signals. The system then waits for a measurement task start command from the RS422 / CAN communication interface via a serial port interrupt mechanism. If no response occurs within the waiting time, the system automatically enters a low-power standby state, which can be awakened by an external communication bus event. After the device is powered on, the ADC module of the intelligent signal decoupling unit acquires the piezoelectric signals from the valid input channels. Based on the dynamic range of the charge amplifier input voltage, it adaptively adjusts the gain of the PGA113 and determines the voltage range of each channel using a dual-threshold method. The main controller then uses an M-order FIR bandpass filter algorithm based on a Hanning window function to denoise the raw voltage signals from multiple channels and calculates the sensor's F / T measurement using a six-dimensional force signal decoupling algorithm. Finally, the system displays the measurement status of each F / T sensor through a status indicator module and outputs the sensor's measurement results in real time via the serial communication interface. The signal decoupling process repeats after the current polling cycle completes. If the measurement task is completed, the system will enter the standby state again and continue to wait for the next measurement task. In this embodiment, the order M is 50.

[0080] like Figure 5 and Figure 6 As shown, in order to reduce the size of the device, the present invention also provides an integrated hardware solution. The present invention also includes a housing, the main controller and onboard power supply of the intelligent data decoupling unit are integrated on a first PCB circuit board, and the first PCB circuit board is arranged in the middle of the housing; a plurality of charge signal processing modules are respectively integrated on a second PCB circuit board and a third PCB circuit board, and the second PCB circuit board and the third PCB circuit board are respectively fixedly arranged in the housing on both sides of the first PCB circuit board, and the human-computer interaction module and the communication module are embedded in different surfaces of the housing; a plurality of input channels are respectively provided on the second PCB circuit board and the third PCB circuit board, and the input channels are used to electrically connect to a plurality of piezoelectric six-dimensional force sensors in a one-to-one correspondence; shielding covers are provided on both sides of the second PCB circuit board and the third PCB circuit board; and adjacent PCB circuit boards are fixedly spaced apart by copper pillars.

[0081] like Figure 5 and Figure 6As shown, the overall package volume of the device is L*W*H=80*60*50mm. The box body is divided into an aluminum upper shell 3 and a lower shell 6, and the upper shell 3 is covered on the lower shell 6. The interior of the box body is hollow, and the status indicator light 1 and LCD display 2 are set on one side of the upper cover 3; the USB-C communication interface 4 and the CAN bus interface 5 are embedded in one side of the lower shell 6, and the XT30DC power supply interface 11 and the RS422 bus interface 12 are embedded in the other side of the lower shell 6. The piezoelectric six-dimensional force sensor output interface 7, that is, Figure 1 The SMA terminals are electrically connected one-to-one to different charge signal processing modules on the second PCB 8 and the third PCB 9, and are electrically connected to the piezoelectric six-axis force sensor via high-resistance cables. The side of the second PCB 8 and the third PCB 9 facing away from the first PCB 10 houses a precision charge amplifier circuit, a programmable voltage gain circuit, and its shielding cover (corresponding to 13), as well as an active low-pass filter circuit, a DC bias and reference voltage generation circuit, and an internal temperature compensation circuit and its shielding cover (corresponding to 14). A bottom shielding cover 15 is located on the side of the second PCB 8 and the third PCB 9 facing the first PCB 10.

[0082] The device's internal circuit board connection method uses a three-layer PCB structure stacked up top and bottom, in which the front-end signal acquisition unit is divided into two identical PCBs, located on the upper and lower layers of the structure, and fixedly connected to the first PCB circuit board where the intelligent data decoupling unit is located in the middle via a direct-insert signal connector 16 between the PCB boards. A copper shield is arranged on the inner side of the PCB circuit board where the front-end signal acquisition unit is located to isolate the high-frequency digital noise of the middle-layer data processing unit; the outer side contains the circuit area of ​​the charge signal processing module, and three separate copper shields are arranged to shield the electrostatic noise coupled from the environment. The stacked PCB circuit boards are fixed between the boards using copper columns and are installed in the internal positioning threaded holes of the upper and lower aluminum shells with bolts.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system, characterized in that: include: Several piezoelectric six-dimensional force sensors collect six-dimensional force raw signals and output charge signals through cables; The front-end signal acquisition unit is used to receive the charge signals output by several piezoelectric six-dimensional force sensors in parallel, process the charge signals, and output analog signals. The intelligent data decoupling unit is electrically connected to the front-end signal acquisition unit, and is used to receive the analog signal output by the front-end signal acquisition unit, and perform data decoupling and measurement error compensation on the six-dimensional force original signal corresponding to the analog signal through the built-in decoupling and error compensation algorithm to obtain a decoupled six-dimensional force signal; Among them, the intelligent data decoupling unit also provides power to the front-end signal acquisition unit; The intelligent data decoupling unit includes a main controller, a human-computer interaction module, an onboard power supply and a communication module; the main controller is connected to the human-computer interaction module and the communication module, and the main controller has a built-in decoupling and error compensation algorithm for receiving the analog signal output by the front-end signal acquisition unit, performing data decoupling and measurement error compensation on the analog signal, obtaining a decoupled six-dimensional force signal and sending it to the human-computer interaction module and the communication module respectively; the onboard power supply supplies power to the main controller and the human-computer interaction module, and serves as an external power input for several charge signal processing modules; the human-computer interaction module is used to output and display the decoupled six-dimensional force signal; the communication module is used for parameter configuration, equipment debugging or transmitting the decoupled six-dimensional force signal to the host computer or Internet of Things device in real time; Decoupling and measurement error compensation algorithms, including the following: S1: The main controller is equipped with an ADC module, and the input channels of the ADC module are set in a one-to-one correspondence with the output terminals of several charge signal processing modules; the main controller adjusts the gain level of the programmable voltage gain circuit to determine the range of the voltage signal after the programmable gain; S2: The main controller uses the M-order FIR bandpass filter algorithm based on the Hanning window function to denoise the input analog signal and obtain the original voltage signal U n And stored in the FIFO buffer queue of the main controller, the original voltage signal U that meets the voltage range of the analog signal n Extract and compensate the gain of the original voltage signal input by each input channel of the ADC module: U 1×n =G 1×n U n , n=6,7,8,G 1×n is the gain compensation, and is the original voltage signal U after gain compensation 1×n Then, according to the charge mapping relationship of each channel, the six-dimensional charge accumulation integral U linearly related to each force is calculated. FT :U FT =[U Fx , U Fy , U Fz , U Mx , U Mx , U Mx ]=U 1×n I n×6 , U Fx , U Fy , U Fz , U Mx , U Mx , U Mx is the six-dimensional charge cumulative integral, I n×6 is the channel mapping matrix; S3: Piezoelectric conversion gain coefficient vector A of the piezoelectric six-axis force sensor calibrated using the linear regression method 1×6 and the bias coefficient vector b 1×6 :FT 1×6 =A 1×6 U FT +b 1×6 , FT 1×6 The six-dimensional force raw signal measurement data for preliminary decoupling; S4: Perform secondary decoupling on the initially decoupled six-axis force original signal measurement data, calibrate the multi-axis coupling error of the piezoelectric six-axis force sensor based on the least squares method, and use the decoupling coefficient matrix obtained by optimal estimation Solve the precise measurement result FT of the six-dimensional force original signal of the piezoelectric six-dimensional force sensor d :FT d =D 6×6 FT 1×6 ,in D 6×6 is the decoupling coefficient matrix, is the actual measurement value of the axial calibration test; S5: The measurement error compensation algorithm includes quasi-static charge leakage correction and temperature drift compensation. Quasi-static charge leakage correction uses the charge discharge analog switch SW1 in the precision charge amplifier circuit. After the front-end signal acquisition unit completes initialization and starts the measurement task, it first performs a charge discharge reset operation and continuously collects the static charge signals U of several piezoelectric six-axis force sensors for a period of time. Raw , record the current ambient temperature T, and when the effective data volume reaches the set threshold, perform linear fitting on the charge leakage coefficients corresponding to several input channels to obtain the charge leakage rate v under the current ambient temperature parameters N and the quasi-static charge bias s N (T), the main controller calculates the real-time compensation charge measurement result U through the following formula N :U N =v N U Raw +s N (T), N=[1, 2,..., n]; Temperature drift compensation uses the internal temperature compensation circuit and the current ambient temperature T. After the front-end signal acquisition unit is powered on, the output power of the heating power resistor array is adjusted through a proportional regulation method according to the set temperature holding threshold so that the front-end signal acquisition unit reaches the set operating temperature. The main controller adjusts the duty cycle of the heating drive signal of the power drive unit according to the deviation between the calculated temperature measurement value and the set temperature holding threshold to keep the operating temperature of the front-end signal acquisition unit constant. S6: The main controller corrects the calculated real-time compensation charge measurement result to compensate for the quasi-static charge leakage and temperature drift, and saves the compensation amount at the current temperature in the main controller.

2. A miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 1, characterized in that: The front-end signal acquisition unit includes several input channels and several charge signal processing modules. The several charge signal processing modules are electrically connected to several piezoelectric six-dimensional force sensors through the input channels in a one-to-one correspondence, and are used to independently process the six-dimensional force original signal received by each input channel.

3. A miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 2, characterized in that: Several charge signal processing modules all include a precision charge amplifier circuit, a programmable voltage gain circuit, an active low-pass filter circuit, a DC bias and reference voltage generating circuit and an internal temperature compensation circuit; wherein, the precision charge amplifier circuit is used to convert the charge signal corresponding to the input six-dimensional force original signal into a primary voltage signal, and the converted primary voltage signal is sent to the programmable voltage gain circuit, and the programmable voltage gain circuit converts the primary voltage signal to obtain a voltage signal after programmable gain; the active low-pass filter circuit receives the voltage signal after programmable gain, filters the voltage signal after programmable gain, and obtains a denoised voltage signal which is sent to the DC bias and reference voltage generating circuit, and the DC bias and reference voltage generating circuit adds a DC bias to the denoised voltage signal to obtain an analog signal that meets the input range of the intelligent data decoupling unit; the internal temperature compensation circuit is respectively for the ambient temperature self-stabilization during the power-on process of several charge signal processing modules and the constant temperature control during the online measurement process.

4. A miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 3, characterized in that: The precision charge amplifier circuit includes an electrometer operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a charge discharge analog switch SW1. One end of the first resistor R1 is electrically connected to the non-inverting input end of the electrometer operational amplifier U1, and the other end of the first resistor R1 is grounded. The inverting input end of the electrometer operational amplifier U1 is electrically connected to one end of the second resistor R2, one end of the third resistor R3, one end of the first capacitor C1, and a normally open contact of the charge discharge analog switch SW1, respectively. The other end of the second resistor R2 is electrically connected to the output end of a piezoelectric six-axis force sensor through an input channel. The other end of the third resistor R3, the other end of the first capacitor R1, and the normally open contact of the charge discharge analog switch SW1 are all electrically connected to the output end of the electrometer operational amplifier U1. After the coil of the charge discharge analog switch SW1 is energized, the normally open contact of the charge discharge analog switch SW1 is closed and grounded. The precision charge amplifier circuit converts the charge signal sent by the second resistor R2 into a primary voltage signal and outputs it to the programmable voltage gain circuit. The programmable voltage gain circuit includes a programmable gain amplifier U2, wherein the non-inverting input terminal of the programmable gain amplifier U2 is electrically connected to the output terminal of the electrometer operational amplifier U1, the inverting input terminal of the programmable gain amplifier U2 is grounded, and the programmable terminal of the programmable gain amplifier U2 is communicatively connected to the intelligent data decoupling unit; the output terminal of the programmable gain amplifier U2 is electrically connected to the input terminal of the active low-pass filter circuit; The active low-pass filter circuit includes two groups of low-pass filter modules connected in series, each low-pass filter module includes an active amplifier U3, a fourth resistor R4, a fifth resistor R5, a second capacitor C2 and a third capacitor C3, the non-inverting input terminal of the active amplifier U3 is electrically connected to one end of the fifth resistor R5 and one end of the third capacitor C3 respectively, the other end of the third capacitor C3 is grounded, the other end of the fifth resistor R5 is electrically connected to one end of the second capacitor C2 and one end of the fourth resistor R4 respectively, the other end of the second capacitor C2 and the inverting input terminal of the active amplifier U3 are both electrically connected to the output terminal of the active amplifier U3, the other end of the fourth resistor R4 of the front-stage low-pass filter module is electrically connected to the output terminal of the programmable gain amplifier U2 as the input terminal of the active low-pass filter circuit, the output of the active amplifier U3 of the front-stage low-pass filter module serves as the input of the rear-stage low-pass filter module, and the output of the active amplifier of the rear-stage low-pass filter module serves as the output of the active low-pass filter circuit; The DC bias and reference voltage generating circuit includes a precision amplifier U4, a voltage reference chip U5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9. The input end of the voltage reference chip U5 is electrically connected to the external power input, one end of the ninth resistor R9 is electrically connected to the output end of the voltage reference chip U5, the other end of the ninth resistor R9 is electrically connected to one end of the eighth resistor R8, the power input end of the programmable gain amplifier U2, the power input end of the internal temperature compensation circuit and the input of the precision amplifier U4, respectively, and the other end of the eighth resistor R8 is grounded; the input end of the precision amplifier U4 is also electrically connected to the output end of the active low-pass filter circuit, the inverting input end of the precision amplifier U4 is electrically connected to one end of the sixth resistor R6 and one end of the seventh resistor R7, the other end of the sixth resistor R6 is grounded, and the other end of the seventh resistor R7 is electrically connected to the output end of the precision amplifier U4. The output end of the precision amplifier U4 outputs an analog signal that meets the input range of the intelligent data decoupling unit; The internal temperature compensation circuit includes a power drive unit and a heating power resistor array. The power drive unit adopts a totem pole push-pull output structure based on an NMOS tube to provide an input signal for the heating power resistor array; the heating power resistor array is arranged one-to-one in several charge signal processing modules; the heating drive signal input end of the power drive unit is electrically connected to the intelligent data decoupling unit.

5. The miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 1, characterized in that: The main controller described in step S1 adjusts the gain gear of the programmable voltage gain circuit to determine the range of the voltage signal after the programmable gain, and determines the range of the voltage signal after the programmable gain by a double threshold method; first, the starting range of the voltage signal after the programmable gain is set, and the ADC module of the main controller collects the analog signal corresponding to the output of the current piezoelectric six-dimensional force sensor, and uses the sliding window method to filter the voltage data within the holding time range to obtain the average reference value of the voltage measurement result of the current analog signal, set the voltage upper and lower threshold parameters and, and compare them with the measured value, let the voltage upper threshold parameter of the current range be V upper , the voltage lower threshold parameter of the current range is V lower The voltage upper and lower threshold parameters are V th =V lower +V upper , the current measured value is V measured , the main controller determines the current optimal gain gear through the following discriminant: Where δ is the allowable deviation, which shall not exceed 1% of the sum of the upper and lower threshold parameters of the current range voltage.

6. The miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 1, characterized in that: The main controller in step S2 uses an M-order FIR bandpass filtering algorithm based on a Hanning window function to denoise the input analog signal, including the following: defining the impulse response h of an ideal low-pass filter LP (m): where f c is the cutoff frequency, f s is the sampling frequency, M is the filter order, m=0, 1, 2, ..., M, x is the variable in the brackets; let the lower cutoff frequency of the FIR bandpass be f1 and the upper cutoff frequency of the FIR bandpass be f2, then the impulse response function of the FIR bandpass is Multiply each point by the window function w(n) to suppress frequency leakage in the FIR process: h(m) = h BP (m)·w(n), The frequency response function of the M-order FIR bandpass filter algorithm based on the Hanning window function is:

7. The miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 1, characterized in that: The onboard power supply obtains a 5V power rail through a DC regulated power supply, adapter input, or USB interface. The 5V power supply is stepped down to obtain a 3.3V power rail for the main controller. The 5V power supply is stepped up and reversed to obtain a +12V power rail and a -12V power rail for several charge signal processing modules.

8. The miniaturized intelligent signal decoupling device suitable for a piezoelectric multi-dimensional force measurement system according to claim 1, characterized in that: The device further includes a housing, wherein the main controller and onboard power supply of the intelligent data decoupling unit are integrated on a first PCB circuit board, which is disposed in the middle of the housing; a plurality of charge signal processing modules are respectively integrated on a second PCB circuit board and a third PCB circuit board, which are respectively fixedly disposed in the housing on both sides of the first PCB circuit board at intervals; a human-computer interaction module and a communication module are embedded in different surfaces of the housing; a plurality of input channels are respectively disposed on the second PCB circuit board and the third PCB circuit board, the input channels being used to electrically connect to a plurality of piezoelectric six-dimensional force sensors in a one-to-one correspondence; shielding covers are disposed on both sides of the second PCB circuit board and the third PCB circuit board; and adjacent PCB circuit boards are spaced and fixed by copper pillars.

Images