Summary of the invention
The electromagnetic test sensing device of the multiple incentive mode of a kind of multifrequency provided by the invention, for metal defect detection, can set the EMT technology flexibly and change the system incentive frequency, thereby being suitable for different measured matters are detected; The incentive mode of switched system, under varying environment and application scenario, can select the incentive mode be applicable to flexibly, thereby reach optimum detection effect; Timesharing cycle motivation and detection mode have been adopted, thereby can obtain the detection information in each orientation of measured matter, make the sampled data quantity of information more more comprehensively abundant, system detection sensitivity and accuracy of detection have been improved, can realize online real-time tested metal is detected, improve to detect the real-time of data, and power consumption and cost low.
In order to achieve the above object, the invention provides the electromagnetic test sensing device of the multiple incentive mode of a kind of multifrequency, this electromagnetic test sensing device comprises pumping signal and produces passage, sensor-based system, detection signal input channel, FPGA control system and host computer, pumping signal produces the output terminal that passage connects the FPGA control system, sensor-based system connects pumping signal and produces the output terminal of passage and the input end of detection signal input channel, the detection signal input channel connects the input end of FPGA control system, and host computer connects the output terminal of FPGA control system.
Described FPGA control system comprises control module, FIR module, digital demodulation module, DDS module and the usb communication module that signal connects; Control module produces the gating of multi-way switch of passage and detection signal input channel and the communication of the inner modules of FPGA control system for controlling pumping signal, the FIR module is carried out digital filtering for the sampled data to the input of detection signal input channel, filter out noise and high frequency interference, the digital demodulation module extracts real part and amplitude and the phase information of imaginary part information be used to obtaining detection signal of the signal of detection signal input channel input; The DDS module is exported to pumping signal for generation of pumping signal and is produced passage, and the setting of exciting signal frequency, phase place is very flexible, and the usb communication module is for communicating by letter with host computer.
Described FPGA control system also comprises DAC interface module and ADC interface module, this DAC interface module connects pumping signal by a SMA interface and produces passage, this ADC interface module connects the detection signal input channel by the 2nd SMA interface, and this FPGA control system connects the detection signal input channel by Three S's MA interface.
Described sensor-based system comprises some coils, and described some coils are circumference and distribute symmetrically and evenly.
Described coil preferably arranges 8 coils.
The number of turns of described coil, coiling density and coil impedance value are identical, the inductance value difference of each coil is about 0.2% ~ 0.4% when low frequency, during high frequency, maintain 0.1%, the number of turns scope of coil is 50 ~ 300, and the circle diameter scope of coil is 0.1mm ~ 10mm.
Described pumping signal produces passage and comprises Di Yi tetra-tunnel selector switch and Di Er tetra-tunnel selector switch, and these Di Yi tetra-tunnel selector switch are connected respectively the coil in sensor-based system with Di Er tetra-tunnel selector switch.
Described pumping signal produces passage and also comprises the first power resistor that connects Di Yi tetra-tunnel selector switch, the first power amplifier that connects the first power resistor, connect the first wave filter of the first power amplifier, and a DAC module that connects the first wave filter; This pumping signal produces passage and also comprises the second power resistor that connects Di Er tetra-tunnel selector switch, connects the second power amplifier of the second power resistor, connects the second wave filter of the second power amplifier, and the 2nd DAC module that connects the second wave filter; The one DAC module is connected the FPGA control system with the 2nd DAC module by a SMA interface; The DAC module is carried out digital-to-analog conversion to the pumping signal that the FPGA control system sends; wave filter is to signal filtering; power amplifier carries out power amplification to pumping signal; obtain more intense excitation main field; be conducive to the extraction of detection signal, the step-down of power resistor current limliting, holding circuit; four tunnel selector switch come the corresponding coil of gating as drive coil according to different incentive modes, and pumping signal is applied on drive coil and produces the excitation main field.
Described detection signal input channel comprises Ba Ge tetra-tunnel selector switch, the eight tunnel selector switch that connect Ba Ge tetra-tunnel selector switch that connect respectively the coil in sensor-based system, the PGA module that connects eight tunnel selector switch, connects respectively the latch of Ba Ge tetra-tunnel selector switch, eight tunnel selector switch and PGA module and the ADC module that is connected the PGA module; The ADC module connects the FPGA control system by the 2nd SMA interface, and latch connects the FPGA control system by Three S's MA interface; Four tunnel selector switch are for the gating number of stages of amplification, eight tunnel selector switch are for gating detection signal input channel, detection signal is sent into to the ADC module, namely can only carry out acquisition process to the detection signal of a magnetic test coil at every turn, the PGA module is programmable amplifier, as prime amplifier, latch is for latching the gating signal of detection signal input channel Zhong De tetra-tunnel selector switch and eight tunnel selector switch and described pumping signal input channel Zhong De tetra-tunnel selector switch, and the ADC module is carried out analog to digital conversion to signal.
The present invention compared with prior art, has the following advantages:
1, can set flexibly and change the system incentive frequency, thereby being suitable for different measured matters are detected;
2, the incentive mode of switched system flexibly, under varying environment and application scenario, can select the incentive mode be applicable to, thereby reach optimum detection effect;
3, system has adopted timesharing cycle motivation and detection mode, thereby can obtain the detection information in each orientation of measured matter, makes the sampled data quantity of information more more comprehensively abundant, has improved system detection sensitivity and accuracy of detection;
4, can realize online real-time tested metal is detected, improve the real-time that detects data.
Embodiment
Following according to Fig. 1~Fig. 5, illustrate preferred embodiment of the present invention.
As shown in Figure 1, the invention provides the electromagnetic test sensing device of the multiple incentive mode of a kind of multifrequency, this electromagnetic test sensing device comprises pumping signal and produces passage 1, sensor-based system 2, detection signal input channel 3, FPGA control system 4 and host computer 5, pumping signal produces the output terminal that passage 1 connects FPGA control system 4, sensor-based system 2 connects pumping signal and produces the output terminal of passage 1 and the input end of detection signal input channel 3, detection signal input channel 3 connects the input end of FPGA control system 4, and host computer 5 connects the output terminal of FPGA control system 4.
As shown in Figure 2, described FPGA control system 4 comprises control module 410, FIR module 44, digital demodulation module 46, DDS module 47 and the usb communication module 45 that signal connects; Control module 410 produces the gating of multi-way switch of passage 1 and detection signal input channel 3 and the communication of FPGA control system 4 inner modules be used to controlling pumping signal, FIR module 44 is carried out digital filtering for the sampled data to 3 inputs of detection signal input channel, filter out noise and high frequency interference, digital demodulation module 46 extracts real part and amplitude and the phase information of imaginary part information be used to obtaining detection signal of the signal of detection signal input channel 3 inputs; DDS module 47 is exported to pumping signal for generation of pumping signal and is produced passage 1, and the setting of exciting signal frequency, phase place is very flexible, and usb communication module 45 is for communicating by letter with host computer 5.
This FPGA control system 4 also comprises DAC interface module 49 and ADC interface module 48, this DAC interface module 49 connects pumping signal by a SMA interface 41 and produces passage 1, this ADC interface module 48 connects detection signal input channel 3 by the 2nd SMA interface 42, and this FPGA control system 4 connects detection signal input channel 3 by Three S's MA interface 43.
As shown in Figure 3, described sensor-based system 2 comprises 8 coils 21 ~ 28, and described 8 coils 21 ~ 28 are circumference and distribute symmetrically and evenly; The number of turns of 8 coils, coiling density and coil impedance value are identical, and the inductance value difference of each coil is about 0.2% ~ 0.4% when low frequency, during high frequency, maintain 0.1%; The number of turns scope of 8 coils is 50 ~ 300; The circle diameter scope of 8 coils is 0.1mm ~ 10mm.
As shown in Figure 4, described pumping signal produces passage 1 and comprises Di Yi tetra-tunnel selector switch 11 and Di Er tetra-tunnel selector switch 12, and these Di Yi tetra-tunnel selector switch 11 are connected respectively 8 coils 21 ~ 28 in sensor-based system 2 with Di Er tetra-tunnel selector switch 12; This pumping signal produces passage 1 and also comprises the first power resistor 13 that connects Di Yi tetra-tunnel selector switch 11, the first power amplifier 15 that connects the first power resistor 13, connect the first wave filter 17 of the first power amplifier 15, and a DAC module 19 that connects the first wave filter 17; This pumping signal produces passage 1 and also comprises the second power resistor 14 that connects Di Er tetra-tunnel selector switch 12, the second power amplifier 16 that connects the second power resistor 14, connect the second wave filter 18 of the second power amplifier 16, and the 2nd DAC module 110 that connects the second wave filter 18; The one DAC module 19 is connected FPGA control system 4 with the 2nd DAC module 110 by a SMA interface 41; The DAC module is carried out digital-to-analog conversion to the pumping signal that FPGA control system 4 sends; wave filter is to signal filtering; power amplifier carries out power amplification to pumping signal; obtain more intense excitation main field; be conducive to the extraction of detection signal, the step-down of power resistor current limliting, holding circuit; four tunnel selector switch come the corresponding coil of gating as drive coil according to different incentive modes, and pumping signal is applied on drive coil and produces the excitation main field.
Pumping signal produces passage 1 and provides stable two-way sinusoidal excitation signal for sensor-based system 2, by controlling the gating of Liang Ge tetra-tunnel selector switch, can realize respectively single excitation, adjacent excitation, relative incentive mode: when single excitation referred to each detection, coil of a gating was as drive coil, and all the other seven coils are as magnetic test coil; Two coils that when adjacent excitation referred to each the detection, gating was adjacent are as drive coil, and all the other coils are as magnetic test coil; Two coils that when excitation referred to each the detection relatively, gating was relative are as drive coil, and all the other coils are as magnetic test coil; Three kinds of incentive modes are all by FPGA control system 4, to carry out the mode of operation of switching coil while detecting at every turn, realize system timesharing cycle motivation, thereby obtain multi-faceted more specifically detection data relevant to metal defect.
As shown in Figure 5, detection signal input channel 3 comprises the Ba Ge tetra-tunnel selector switch 33 that connect respectively 8 coils 21 ~ 28 in sensor-based system 2, the PGA module 36 that connects Ba Ge tetra-tunnel selector switch 33De eight tunnel selector switch 35, connection eight tunnel selector switch 35, connects respectively Ba Ge tetra-tunnel selector switch 33, eight tunnel selector switch 35 and the latch 37 of PGA module 36 and the ADC module 38 that is connected PGA module 36; ADC module 3 connects FPGA control system 4 by the 2nd SMA interface 42, and latch 37 connects FPGA control system 4 by Three S's MA interface 43; Four tunnel selector switch are for the gating number of stages of amplification, eight tunnel selector switch 35 are for gating detection signal input channel, detection signal is sent into to ADC module 38, namely can only carry out acquisition process to the detection signal of a magnetic test coil at every turn, PGA module 36 is programmable amplifier, as prime amplifier, latch 37 is be used to latching the gating signal of detection signal input channel 3 Zhong De tetra-tunnel selector switch and eight tunnel selector switch and described pumping signal input channel 1 Zhong De tetra-tunnel selector switch, and 38 pairs of signals of ADC module carry out analog to digital conversion.
Host computer 5 is connected with FPGA control system 4 by communication interface, for sampled data is analyzed and image reconstruction.
When using this device, while starting to detect, tested metal is placed under electromagnetic test sensing device of the present invention, make sensor-based system perpendicular on tested metal, its lift off was more is 10mm.Host computer sends starts working instruction and sends the exciting signal frequency control signal, after control module in the FPGA control system is received instruction, to pumping signal, produce passage and send the corresponding coil of enable signal gating as drive coil and measuring coil, control simultaneously the pumping signal of the DDS module generation assigned frequency in the FPGA control system and produce passage by pumping signal and give the drive coil that is applied to gating, the gating that produces the Liang Ge tetra-tunnel selector switch in passage by controlling pumping signal can be realized the switching of three kinds of incentive modes, for example one of them switch of a gating has been realized single incentive mode, two switches all gating have been realized the twin coil excitation, more can realize very easily adjacent incentive mode and relative incentive mode by the position of controlling gate winding.Pumping signal is applied on the drive coil of gating and can in the measured object field, produces the excitation main field, magnetic test coil obtains induced voltage by the mode of induction, control detection signal input channel Zhong De eight tunnel selector switch and realize detecting successively and the digital demodulation module that the sampled voltage signal at magnetic test coil two ends is delivered in the FPGA control system being carried out to amplitude and the phase information that data demodulates is obtained detectable voltage signals of magnetic test coil, and this information is uploaded to host computer, position by the tested metal plate defect of the reversible release of certain image reconstruction algorithm, size, the parameters such as shape.
Because needs obtain more fully the electromagnetic property distribution parameter of tested metal more specifically, need to apply to tested metal the exciting field of different directions, thereby obtain the distributed data in each orientation, measured object field, the present invention is easy to realize tested metal is carried out the data acquisition in each orientation, by the Liang Ge tetra-tunnel selector switch in control pumping signal generation passage and the enable signal of detection signal input channel Zhong De eight tunnel selector switch, can to the coil working pattern, switch easily, change the position of drive coil, thereby change the direction of excitation main field.
It is below the control example of the coil working pattern switching of a concrete adjacent incentive mode line.Detection for the first time as system, the enable signal that pumping signal produces the Liang Ge tetra-tunnel selector switch in passage is 1000, it is gate winding 21,22 is drive coil, coil 23 ~ 28 is magnetic test coil, the enable signal of 8 tunnel selector switch in the detection signal input channel is followed successively by 00100000,00010000,00001000,00000100,00000010,00000001, realized that namely the detectable voltage signals of six sense channels that six magnetic test coils are corresponding is sent into the demodulation of carrying out sampled data in the FPGA control system successively, after all sense channels measure, by the control module in the FPGA control system, realize the switching of coil working pattern, the enable signal that pumping signal is produced to the Liang Ge tetra-tunnel selector switch in passage becomes 0100, 1000, it is gate winding 22, 23 is drive coil, coil 21, 24 ~ 28 is magnetic test coil, the enable signal of 8 tunnel selector switch in the detection signal input channel is followed successively by 10000000, 00010000, 00001000, 00000100, 00000010, 00000001, so just realized the switching of coil working pattern successively, when all sense channels measure backgating coil 23, 24 is drive coil, so circulation is gone down, can realize excitation and detection to each orientation of tested metal, the distributed intelligence relevant to tested metal collected like this is also the most comprehensive, be conducive to tested metal construction is realized detecting comparatively accurately.
Multi-frequency Characteristic for the multiple incentive mode electromagnetic test of multifrequency of the present invention sensing device refers to that device of the present invention can be suitable for the measured matter of unlike material is detected, measured matter is detected to the Optimum Excitation frequency that need to find this measured matter, the present invention is in the design of FPGA control system, set up the Optimum Excitation frequency storehouse of different measured matters, can realize easily that by the DDS module Optimum Excitation frequency of unlike material needs is set pumping signal.
Because the electromagnetic test sensing device of the multiple incentive mode of multifrequency of the present invention can be realized single excitation, adjacent excitation and relative excitation flexibly, so with respect to the device that can only realize single incentive mode, the present invention has very large advantage, and advantage separately that can comprehensive three kinds of incentive modes improves sensitivity and the accuracy of detection of device.Three kinds of incentive modes respectively have superiority, and are suitable for the measurement of different occasions, with regard to tested induced voltage scope, adjacent incentive mode maximum, single incentive mode takes second place, and incentive mode, due to magnetic test coil and drive coil space angle minimum, is exported the data area minimum relatively; With regard to the range of sensitivity, single incentive mode maximum, adjacent incentive mode takes second place, relative incentive mode minimum, single incentive mode has more advantage in the image reconstruction application; Specific physical structure due to the latter two incentive mode, under special environment, have more advantage, relatively the incentive mode induction field induction field center that is evenly distributed is highly sensitive, be applicable to induction field central area image reconstruction, adjacent incentive mode induction field non-uniform Distribution, magnetic field intensity is larger than central magnetic field intensity on border, causes borderline sensitivity high, center sensitivity is low, and it is more suitable for the borderline region image reconstruction.
Although content of the present invention has been done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.After those skilled in the art have read foregoing, for multiple modification of the present invention with to substitute will be all apparent.Therefore, protection scope of the present invention should be limited to the appended claims.