Background technology
Along with the requirement of quality monitoring is more and more stricter, Dynamic Non-Destruction Measurement is also had higher requirement.In industrially developed country, Non-Destructive Testing is arranged side by side with design, material, manufacturing (technology), become four big gordian techniquies of industrial circle, many relevant industries such as machinery, petrochemical industry, Aeronautics and Astronautics, automobile, pressure vessel, railway, road, nuclear industry and technical field are played an important role.
When existing eddy detection technology detects many materials such as tubing, wire rods, material require passes drive coil and receiving coil, the vortex flow that drive coil induces is axial perpendicular to material surface, therefore the axial defective of material surface is bigger to the influence of excitation electromagnetic field, is easy to detect; And the circumferential defective of material surface is owing to be parallel to the vortex flow of drive coil induction, and the circumferential defective of material surface is smaller for the influence that detects magnetic field like this, very difficultly discerned by receiving coil.Because eddy current probe is insensitive to the circumferential defective of material, is easy to cause omission, influences the quality of material and Related product, therefore, eddy current probe is badly in need of being improved.
Summary of the invention
For solving above-mentioned middle problem and the defective that exists, the invention provides a kind of polyphase eddy detection system.
The present invention is achieved by the following technical solutions:
A kind of polyphase eddy detection system involved in the present invention comprises:
Excitation and receiver module are used to receive exciting current, produce rotating magnetic field, receive detection signal, and export described detection signal;
Signal processing module is used to receive described detection signal, and according to described detection signal, the quality of assessment object under test.
Described excitation and receiver module comprise at least three group drive coil and receiving coils.
Described excitation and receiver module further comprise:
The exciting current receiving element is used to receive exciting current, produces rotating magnetic field, the scanning object under test; The detection signal receiving element, the detection signal that is used to receive, and with described detection signal output.
Described exciting current receiving element comprises at least three drive coils; Described detection signal receiving element comprises at least three receiving coils, and drive coil equates with receiving coil quantity, and is corresponding one by one.
The beneficial effect of technical scheme provided by the invention is:
Can realize the electromagnetic testing system of multiphase eddy flow measuring ability, by rotation sweep magnetic field material be detected, simplify the design of detection system, reduce the cost that detects, this system has advantage simple and reliable and flexible and convenient to use.
Embodiment
For making the purpose, technical solutions and advantages of the present invention clearer, embodiment of the present invention is done to retouch in detail further below in conjunction with accompanying drawing.
Present embodiment provides a kind of polyphase eddy detection system.
Its structural representation is as shown in Figure 2: in this embodiment, excitation realizes by the multiphase eddy flow probe with receiver module, comprises drive coil group and receiving coil group; The drive coil group comprises at least three drive coils, and the receiving coil group comprises at least three receiving coils;
Signal processing module comprises communication interface, demonstration and printing device, SDRAM storer, CPU, FLASH storer, FPGA, D/A converter, A/D converter, multi-way switch, signal condition unit, low-pass filtering, prime amplifier, power amplifier and multipath conversion unit;
Wherein, CPU be used for to detection system communicate by letter outward, data presentation is printed and storage, FPGA is used for the logical sequence control and the digital signal processing of each several part in the disposal system; The multiphase eddy flow probe is used to produce rotating magnetic field, and the scanning object under test generates detection signal, exports described detection signal to signal processing module.
The specific implementation step comprises:
Step 1, CPU4 sets sinusoidal wave frequency according to detecting needs, and setup parameter is sent to FPGA6;
Step 2, FPGA6 generates a sinusoidal wave amplitude table according to detected parameters, and stores in the storer of FPGA6 inside, and FPGA6 exports D/A converter 7 to according to setting the data of sequential with the amplitude table;
Step 3, D/A converter 7 converts the data of FPGA6 output to simulating signal by digital signal, and described analog passband signal is crossed the different drive coils in multi-way switch 9, the drive coil group in low-pass filtering 11 and power amplification unit 13 are applied to the multiphase eddy flow probe respectively;
In the step 4,15 groups of drive coils, because the exciting current in the different drive coils has different phase places, the resultant magnetic field that these exciting currents produced is a rotating magnetic field, and the scanning object under test generates detection signal; Receiving coil 16 in the receiving coil group will receive the relevant detection signal, and with its detection signal that receives by multipath conversion 14, prime amplifier 12 and signal condition unit, transfer to A/D converter 8, described A/D converter 8 becomes digital signal with the analog signal conversion that receives, and export described digital signal to FPGA6, carry out Digital Signal Analysis and processing in FPGA6 inside;
Step 5, FPGA6 sends to CPU4 with its resulting result after the digital signal that receives is carried out numerical analysis and handled, that CPU4 receives it, through FPGA6 analyze with handle after detection signal store 5, show or print processing such as 2.
Here need to prove: for the multiphase eddy flow probe, n group drive coil and receiving coil are arranged usually, pass to sinusoidal current respectively in n drive coil, described sinusoidal current can be expressed as respectively:
i
1=I×sin(wt)
i
2=I×sin(Wt-2π/n)
i
n=I×sin(Wt-2(n-1)π/n)
Then as shown in Figure 2 in the different magnetic field position that produce constantly of multiphase eddy flow probe.
Present embodiment passes to the sine-wave excitation electric current of out of phase respectively by a plurality of drive coils, and the resultant magnetic field is at coil enclosed space rotation sweep, and during detection, rotation sweep magnetic field is rotated scanning to material surface, thereby realizes EDDY CURRENT.This system has characteristics simple and reliable and flexible and convenient to use, is suitable for metal pipe material, wire rod are detected.
The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.