阅读说明：本技术 一种基于传感器阵列的16通道导波聚焦检测系统 (A kind of 16 channel guided wave focus detection systems based on sensor array ) 是由 吕炎 洪华星 宋国荣 邢智翔 任晢文 何存富 于 2019-07-23 设计创作，主要内容包括：本发明公开了一种基于传感器阵列的16通道导波聚焦检测系统,用于多阵元传感器阵列的超声导波信号的激励与采集。由16通道信号激励电路、压电传感器阵列、16通道同步采集电路、USB传输模块、电源模块以及上位机组成。多通道激励与采集系统均由FPGA作为主控核心,上位机通过RS232串口将激励系统的参数传输至激励主控FPGA,控制产生16通道的导波激励信号,激励信号再经由各自的信号放大电路升压后激励压电传感器阵列,各传感器接收的反射回波信号经隔离限幅电路、信号调理电路后被高速AD采集,通过USB将数据传输至上位机。本发明产生的16通道高压窄带激励信号,各通道参数独立可调,通过各通道延时激励可实现导波的聚焦检测,有效提高了小缺陷的检出率。(The invention discloses a kind of 16 channel guided wave focus detection systems based on sensor array, the excitation and acquisition of the ultrasonic guided wave signals for more array element sensor arrays.It is made of 16 channel signal exciting circuits, piezoelectric sensor array, 16 Channel Synchronous Acquisition Circuits, USB transmission module, power module and host computer.Multichannel excitation and acquisition system by FPGA as master control core, the parameter of excitation system is transmitted to excitation master control FPGA by RS232 serial ports by host computer, control generates the guided wave pumping signal in 16 channels, pumping signal motivates piezoelectric sensor array after boosting again via respective signal amplification circuit, each received reflection echo signal of sensor, by high-speed AD acquisition, sends data to host computer by USB after isolation amplitude limiter circuit, signal conditioning circuit.The 16 channel high pressure narrowband excitation signals that the present invention generates, each channel parameters Independent adjustable are motivated the focus detection that guided wave can be achieved by each communication channel delay, effectively increase the recall rate of small defect.)

1. a kind of 16 channel guided wave focus detection systems based on sensor array, it is characterised in that: the system is believed by 16 channels Number exciting circuit, piezoelectric sensor array, 16 Channel Synchronous Acquisition Circuits, USB transmission module, power module and upper unit At；The 16 channel actuation circuit output is connected to piezoelectric sensor array by respective coaxial line；Piezoelectric sensor array connects The echo-signal of receipts is connected to 16 Channel Synchronous Acquisition Circuit input terminals by identical coaxial line；16 Channel Synchronous Acquisition Circuits Data transmission is realized by USB data line and host computer interconnection.

2. a kind of 16 channel guided wave focus detection systems based on sensor array according to claim 1, feature exist In: the 16 channel signal exciting circuit is made of fpga core circuit, signal generating circuit and high pressure power amplifier module array； FPGA is signal generating circuit output control signal as control core, and Hanning window needed for generating excitation guided wave is modulated mostly all Phase sinusoidal signal, the multicycle sinusoidal signal of Hanning window modulation carries out voltage amplification via high pressure power amplifier again, and then drives sensing Device array；

The signal generating circuit is made of parallel D/A converters, 5 rank low pass Butterworth filters and amplifier AD8065；Institute It states the clock pins of D/A converter and data terminal pin connect fpga chip, the difference output of D/A converter connects 5 rank low passes bar The output of special Butterworth filter, filter connects amplifier AD8065；The amplifier AD8065 is defeated by the difference current of D/A converter It is converted into single ended voltage output out, while amplifying as the signal of the first order and exporting；The 5 rank low pass Butterworth filter band Width is 15MHz, and the output signal of smooth DA inhibits noise jamming simultaneously；The signal in 16 channels generates hardware scheme phase Together；

The multicycle sinusoidal signal production method of the Hanning window modulation uses Direct Digital, by different cycles number Wave data is stored in the ROM of FPGA, constructs 32 phase accumulators by FPGA, phase accumulator is tired under each clock Dosage is determined by frequency control word, changes frequency control word to change totalizing step to change waveform frequency, phase accumulator Pass through corresponding waveforms amplitude in addressing output ROM；

The high pressure power amplifier module be high voltage operational amplifier PA85 negative feedback amplifier circuit, dual power supply voltage be ± 100V, voltage conversioning rate are 100 times according to 800V/ μ s, amplification factor is configured up to；Power bandwidth is 500kHz, output letter Amplitude is up to 150Vpp when number frequency 500kHz or less, and amplitude is still up to 80Vpp when output signal frequency reaches 2MHz；16 channels Signal exciting circuit includes 16 high pressure power amplifier modules.

3. a kind of 16 channel guided wave focus detection systems based on sensor array according to claim 1, feature exist In: the 16 Channel Synchronous Acquisition Circuit is by isolation amplitude limiter circuit, signal conditioning circuit, converter and master control FPGA group At；Be isolated amplitude limiter circuit export connection signal conditioning circuit, signal conditioning circuit output connection converter, converter when The Differential Input port of clock and data/address bus output connection FPGA；

The isolation amplitude limiter circuit is limiter diode in parallel, and starting voltage clamping action protects late-class circuit, prevents pumping signal High pressure damage Acquisition Circuit；

The signal conditioning circuit is made of programme-controlled gain circuit and filter circuit；Programme-controlled gain circuit selects 4 channels are variable to increase Beneficial amplifier AD8334, gain adjustment range are -4.5dB~43.5dB, and 16 channel signals of system are realized using 4 AD8334 Amplify, every two channel shares a gain-controlled voltage input terminal in AD8334 chip, and 4 AD8334 need to provide the increasing of 8 tunnels Benefit control voltage input, using 8 channels, 8 precision D/A converter AD8801 realize gain control function；The filter circuit Bandwidth is 30MHz, is filtered to amplified signal；

The converter selects AD9284 dual channel high speed ADC, and sample rate is set as 50MS/s, is realized using 8 AD9284 The data in 16 channels acquire, and external sampling clock needed for 8 AD9284 is fanned out to chip 65LVDS108 for 50MHz's by 8 road clocks After sampling clock source crystal oscillator is fanned out to, while clock signal is provided for 8 ADC.

4. a kind of 16 channel guided wave focus detection systems based on sensor array according to claim 3, feature exist In: a piece of 4 channel variable gain amplifier AD8334 and two panels double channel A/D converter AD9284 constitutes a module, real Now to the amplification and acquisition of 4 tunnel input signals, 4 such modules realize the synchronous acquisition of 16 tunnel input signals.

5. a kind of 16 channel guided wave focus detection systems based on sensor array according to claim 1, feature exist In: the power module is included as the power module that 16 channel signals generate and Acquisition Circuit is powered and is 16 high pressure power amplifiers The power module of module for power supply；Described is that 16 channel signals generate the power module with Acquisition Circuit power supply for computer host power supply By voltage conversion chip to provide 1.1V, 2.5V, 3.3V, ± 5V voltage；Described is the electricity of 16 high pressure power amplifier modules power supply The Switching Power Supply of output ± 100V, power 150W by 1 turn of 16 road distributor plate are respectively 16 high pressure power amplifier modules by source module The voltage of offer ± 100V.

6. a kind of 16 channel guided wave focus detection systems based on sensor array according to claim 1, feature exist In: 16 channel encourage have between acquisition system all the way synchronization signal come synchronization motivationtheory channel and all acquisition channels；When When synchronization signal enables, channel output drive signal is motivated, at the same time, the synchronous commencing signal acquisition of all acquisition channels.

Technical field

The present invention realize it is a kind of based on piezoelectric sensor array carry out guided wave focus detection 16 channel guided waves motivate/adopt Collecting system belongs to field of non destructive testing.

Background technique

Ultrasonic guided wave detection technology is to develop a kind of faster non-destructive testing technology in recent years.With traditional ultrasound detection skill Art is compared, and due to the very little that guided wave is decayed on propagation path, it can propagate very remote distance along workpiece, receive It terminates and contains excitation end in the signal received to the structured information of institute between the two o'clock of receiving end；Secondly as ultrasound is led When wave is propagated in being detected workpiece, sound field spreads entire workpiece, therefore can detecte all information of entire workpiece, this is just Mean both to can detecte internal flaw or can detecte surface defect, entire workpiece is comprehensively detected.

According to number of sensors, the detection of guided wave wave can be divided into single-sensor detection and array detection.It is (anti-using single-sensor Penetrate formula) or dual sensor (transmission-type) to carry out Guided waves when, can only realize the defects of single direction range detect, space Go up or cannot focus or can only focus on a certain fixed position.Therefore, single (double) sensor Guided waves sensitivity is lower.

Ultrasonic sensor array overcomes the disadvantages of single transducer resolution ratio is low, detection range is small, can be by a variety of Array format, and the characteristic of supersonic guide-wave is combined, it realizes a wide range of, high-precision defects detection, there is high researching value.Battle array Phased array detection technique in column Guided waves controls each array element in transducer array by electronic system, prolongs according to certain Slow time rule transmitting and reception ultrasonic wave are, it can be achieved that dynamic focusing.

But commercialization multichannel guided wave phased array system is expensive at present, and the hardware and software of instrument is all highly integrated Change, these instruments are transformed or secondary development is very difficult.It can only be by way of manual switching in experimentation The signal with acquisition different sensors is motivated one by one, and experimentation is cumbersome and inefficient, seriously hinders sensor array detection side The research of method is unable to satisfy detection demand.

Summary of the invention

It is an object of the invention in view of the above deficiencies, design a kind of 16 channel guided waves focusing inspection based on sensor array Examining system can realize the focus detection of guided wave, to improve defect by controlling the time-delayed activation in each channel in plate/tube structure Recall rate.The multi-channel system integrated level is high, and collocation host computer is easily operated.

The technical solution adopted by the present invention is the multicycle sinusoidal signal that multichannel pumping signal uses Hanning window modulation, because Hanning window modulated sinusoid is the ideal signal for motivating supersonic guide-wave, its narrow spectrum, and energy is concentrated, and the frequency dispersion that can reduce guided wave is existing As.The case where system uses modularized design, is completely independent between each channel, and there is no multiplexings, each channel is a set of complete Whole ultrasonic signal excitation receives circuit.Interference is generated to circuit is received for anti-high pressure activation signal, by exciting circuit and reception Circuit design is two independent subsystems.

To achieve the above object, a kind of 16 channel guided wave focus detection systems based on sensor array of the present invention, The system is by 16 channel signal exciting circuits, piezoelectric sensor array, 16 Channel Synchronous Acquisition Circuits, USB transmission module, electricity Source module and host computer composition；The 16 channel actuation circuit output is connected to piezoelectric transducer battle array by respective coaxial line Column；The received echo-signal of piezoelectric sensor array is connected to the input of 16 Channel Synchronous Acquisition Circuits by identical coaxial line End；16 Channel Synchronous Acquisition Circuits realize data transmission by USB data line and host computer interconnection.

The 16 channel signal exciting circuit is by fpga core circuit, signal generating circuit and high pressure power amplifier module array group At；FPGA is signal generating circuit output control signal as control core, what Hanning window needed for generating excitation guided wave was modulated Multicycle sinusoidal signal, the multicycle sinusoidal signal of Hanning window modulation carries out voltage amplification via high pressure power amplifier again, and then drives Sensor array.

The signal generating circuit is by parallel D/A converters, 5 rank low pass Butterworth filters and amplifier AD8065 group At；The clock pins of the D/A converter connect fpga chip with data terminal pin, and the difference output of DA converter connects 5 ranks The output of low pass Butterworth filter, filter connects amplifier AD8065；The amplifier AD8065 is by the difference of D/A converter Electric current output is converted into single ended voltage output, while amplifying as the signal of the first order and exporting；The 5 rank low pass Butterworth filter Wave device bandwidth is 15MHz, and the output signal of smooth DA inhibits noise jamming simultaneously.The signal in 16 channels generates hardware design side Case is identical.

The multicycle sinusoidal signal production method of the Hanning window modulation uses Direct Digital, by different cycles Several Wave datas are stored in the ROM of FPGA, construct 32 phase accumulators by FPGA, phase accumulator is under each clock Accumulation amount determined by frequency control word, change frequency control word to change totalizing step to change waveform frequency, phase is tired Device is added to pass through corresponding waveforms amplitude in addressing output ROM.

The high pressure power amplifier module is the negative feedback amplifier circuit of high voltage operational amplifier PA85, and dual power supply voltage is ± 100V, voltage conversioning rate are 100 times according to 800V/ μ s, amplification factor is configured up to；Power bandwidth is 500kHz, output Amplitude is up to 150Vpp when signal frequency 500kHz or less, and amplitude is still up to 80Vpp when output signal frequency reaches 2MHz.16 is logical Road signal exciting circuit includes 16 high pressure power amplifier modules.

The 16 Channel Synchronous Acquisition Circuit is by isolation amplitude limiter circuit, signal conditioning circuit, converter and master control FPGA composition；Amplitude limiter circuit is isolated and exports connection signal conditioning circuit, signal conditioning circuit output connection converter, AD conversion The Differential Input port of clock and data/address bus output the connection FPGA of device.

The isolation amplitude limiter circuit is limiter diode in parallel, and starting voltage clamping action protects late-class circuit, prevents from motivating The high pressure of signal damages Acquisition Circuit.

The signal conditioning circuit is made of programme-controlled gain circuit and filter circuit；Programme-controlled gain circuit selects 4 channels can Variable-gain amplifier AD8334, gain adjustment range are -4.5dB~43.5dB, and realize system using 4 AD8334 16 lead to Road signal amplifies, and every two channel shares a gain-controlled voltage input terminal in AD8334 chip, and 4 AD8334 need to provide The input of 8 road gain-controlled voltages, using 8 channels, 8 precision D/A converter AD8801 realize gain control function.The filtering Circuit bandwidth is 30MHz, is filtered to amplified signal.

The converter selects AD9284 dual channel high speed ADC, and sample rate is set as 50MS/s, using 8 AD9284 Realize the data acquisition in 16 channels, external sampling clock needed for 8 AD9284 is fanned out to chip 65LVDS108 by 8 road clocks will After the sampling clock source crystal oscillator of 50MHz is fanned out to, while clock signal is provided for 8 ADC.

The a piece of 4 channel variable gain amplifier AD8334 and two panels double channel A/D converter AD9284 constitutes one Module, realizes amplification and acquisition to 4 tunnel input signals, and 4 such modules realize the synchronous acquisition of 16 tunnel input signals.

The USB transmission module realizes USB2.0 communication interface using interface chip CH376, can be realized data and control The transmitted in both directions of instruction.

The power module is included as the power module that 16 channel signals generate and Acquisition Circuit is powered and is 16 height Press the power module of power amplifier module power supply；Described is that 16 channel signals generate the power module with Acquisition Circuit power supply for computer master Electromechanical source is by voltage conversion chip to provide 1.1V, 2.5V, 3.3V, ± 5V voltage；Described is that 16 high pressure power amplifier modules supply The Switching Power Supply of output ± 100V, power 150W by 1 turn of 16 road distributor plate are respectively 16 high pressure function by the power module of electricity The voltage of amplification module offer ± 100V.

16 channel is encouraged all the way that come synchronization motivationtheory channel and all acquisitions logical for synchronization signal between acquisition system Road.When synchronization signal enables, channel output drive signal is motivated, at the same time, the synchronous commencing signal of all acquisition channels Acquisition.

The present invention has the effect that (1) present invention can produce ideal signal needed for multichannel motivates guided wave, and can be to more Channel signal synchronizes acquisition, and each interchannel parameter Independent adjustable, level of integrated system is high, can be carried out according to application demand secondary Exploitation, greatly improved experiment and the detection efficiency of sensor array.(2) pressure is combined using multichannel detection system of the invention The deflection and focusing of guided wave may be implemented by generating corresponding time-delayed activation signal to each channel in electric transducer array, thus Small flaw echo energy is effectively improved, the recall rate of defect is improved.

Detailed description of the invention

Fig. 1 is system global structure schematic diagram；

Fig. 2 is single channel excitation control program structure schematic diagram；

Fig. 3 is 5 rank low pass Butterworth filter, one embodiment circuit diagram；

Fig. 4 is PA85 high pressure power amplifier schematic diagram；

Fig. 5 is acquisition system overall structure diagram；

Fig. 6 .a) it is pumping signal time-frequency testing schematic diagram (5 cycle Sine wave 300kHz of Hanning window modulation)；

Fig. 6 .b) it is pumping signal time-frequency testing schematic diagram (10 cycle Sine wave 100kHz of Hanning window modulation)；

Fig. 7 is 4 channels pumping signal test schematic diagram simultaneously；

Specific embodiment

The present invention will be further described below with reference to the drawings:

Fig. 1 show a kind of 16 channel guided wave focus detection system global structures based on sensor array of the present invention Schematic diagram, by 16 channel signal exciting circuits, piezoelectric sensor array, 16 Channel Synchronous Acquisition Circuits, USB transmission module, electricity Source module and host computer composition.Multichannel excitation and acquisition system by FPGA as master control core, host computer passes through The parameter of excitation system is transmitted to excitation master control FPGA by RS232 serial ports, and control generates the guided wave pumping signal in 16 channels, excitation Signal again via piezoelectric sensor array is motivated after the boosting of respective signal amplification circuit, believe by each received reflection echo of sensor Number through isolation amplitude limiter circuit, after signal conditioning circuit by high-speed AD acquisition, host computer is sent data to by USB.

Excitation master control FPGA in the present embodiment selects the EP4CE10F17C8 of altera corp Cyclone IV series, It acquires master control FPGA and selects Cyclone V series 5CEFA7F27C8；FPGA master clock is that 50MHz has source crystal oscillator, program downloading It is JTAG with configuration port.

USB transmission module in the present embodiment realized based on CH376 chip, used the highest parallel interface of speed with FPGA is transmitted.

Synchronization signal is used to synchronization motivationtheory channel and all acquisition channels in the present embodiment, receives for one sharp one or one swashs The system more received, the usually initial time to be acquired at the time of stimulus sensor as all channel signals.Work as synchronization signal When enabled, channel output drive signal is motivated, at the same time, the synchronous commencing signal acquisition of all acquisition channels.

Fig. 2 show single channel excitation control program structure schematic diagram, using based on FPGA and direct digital synthesis technique The scheme of technology (DDS), the program can produce random waveform, therefore the sinusoidal letter of Hanning window modulation needed for can produce excitation guided wave Number；It is stored in after the Wave data of required generation is generated in the ROM of FPGA and is used as inquiry table, building 32 is phase-accumulated in FPGA Device, accumulation amount of the phase accumulator under each clock are determined by frequency control word, change frequency control word to change cumulative step For length to change waveform frequency, phase accumulator passes through corresponding waveforms amplitude in addressing output ROM.To realize that control delay swashs Function is encouraged, constructs delays time to control counter, when count value reaches externally input delay time, enabled phase accumulator starts It is cumulative, achieve the purpose that delay is controllable.FPGA master clock frequency multiplication is 200MHz by PLL phaselocked loop by module drive clock, is driven Dynamic delays time to control counter and phase accumulator, therefore delay resolution is 5ns.

Fig. 3 show 5 rank low pass Butterworth filter, one embodiment circuit diagram, and -3dB cutoff frequency is 15MHz, Play the role of the output signal of smooth DA while inhibiting noise jamming.

Fig. 4 show PA85 high pressure power amplifier schematic diagram, amplifies electricity using the negative-feedback of high voltage operational amplifier PA85 Road, input interface P1 meet signal generating circuit output end, output interface P2 by coaxial line and connect piezoelectric transducer by coaxial line, Input/output interface is all made of SMA interface.R2, C5 form partiting dc circuit, to remove the DC component of input signal；Feedback Resistance Rf is 100K, i.e., amplification factor is 100 times；Pole is inputted using four diode D1, D2, D3, D4 (IN4148) input Clamper protects input terminal in 1.5V；Power supply use ± 100V dual power supply, power pin parallel connection C1, C2, C3, C4 capacitor are done Shunt capacitance guarantees that supply voltage is stablized；Rcl is current limitation resistor；Rc and Cc is phase compensation resistance capacitance, guarantees amplifier The stability of gain bandwidth；D5, D6 are output protection diode, prevent the suddenly change of load current from generating big in output Recoverable voltage peak；Load resistance RL1 is 2K；The amplification of 16 road signals needs 16 identical PA85 high pressure power amplifiers.

Fig. 5 show acquisition system overall structure diagram, a piece of 4 channel variable gain amplifier AD8334 and two panels Double channel A/D converter AD9284 constitutes a module, realizes amplification and acquisition to 4 tunnel input signals, 4 such modules Realize the synchronous acquisition of 16 tunnel input signals；External sampling clock needed for 8 AD9284 is fanned out to chip by 8 road clocks After the sampling clock source crystal oscillator of 50MHz is fanned out to by 65LVDS108, while clock signal is provided for 8 ADC.

Fig. 6 is the single channel pumping signal time-frequency testing schematic diagram of system output, wherein Fig. 6 a) it is in program setting output The 5 cycle sinusoidal signal time-frequency figures that the Hanning window that frequency of heart is 100kHz is modulated, Fig. 6 b) it is that program setting output center frequency is 10 cycle sinusoidal signal time-frequency figures of the Hanning window modulation of 300kHz.From time-domain diagram find out excitation signal amplitude up to 150Vpp, And signal does not obviously distort, noise is relatively good.From spectrogram it can be seen that the output of the centre frequency of signal and program setting Value is coincide substantially.

Fig. 7 show 4 channel of system pumping signal test schematic diagram simultaneously, and output frequency is 300kHz's simultaneously in 4 channels 10 cycle sinusoidal signals of Hanning window modulation, the registration that can be seen that each channel signal by Signal averaging result figure is high, Error is smaller, shows that each interchannel has good consistency.