CN102681019A

CN102681019A - Automatic balance information processing method and device of metallic foreign body detecting machine

Info

Publication number: CN102681019A
Application number: CN2011100566237A
Authority: CN
Inventors: 项安; 张波; 张建忠
Original assignee: SUZHOU TAIYI INSPECTION EQUIPMENT Co Ltd
Current assignee: SUZHOU TAIYI INSPECTION EQUIPMENT Co Ltd
Priority date: 2011-03-09
Filing date: 2011-03-09
Publication date: 2012-09-19
Anticipated expiration: 2031-03-09
Also published as: CN102681019B

Abstract

The invention relates to an automatic balance information processing method and device of a metallic foreign body detecting machine. The method comprises the following steps that: 1) after startup, collecting received phase phi information of a receiving circuit and the amplitude A of an initial receiving signal obtained by the receiving circuit in real time through an A/D (Analog to Digital) sampling circuit, and automatically detecting the balance state of the initial receiving signal; 2) judging whether the balance state meets a set value or not; if yes, not generating a balance signal; and if not, executing a step 3) and the like. The device comprises the receiving circuit, a filtering circuit, the A/D sampling circuit, a real-time phase calculation module, a balance signal generating module, a FPGA (Field Programmable Gate Array), a DSP (Digital Signal Processor), a MCU (Microprogrammed Control Unit), an automatic balance controller, a D/A (Digital to Analog) conversion module and an emission circuit. Compared with the prior art, the method and the device have the advantages that the sensitivity and the stability of the metal detecting machine are increased and the like.

Description

Self-poise information processing method and device in the metallic foreign body machines

Technical field

The present invention relates to a kind of metallic foreign body machines gordian technique, especially relate to self-poise information processing method and device in a kind of metallic foreign body machines.

Background technology

Balanced type metal detection machine receives stress deformation and temperature variation etc. to cause equipoise to change to cause sensitivity to reduce, even completely loses detectability.Therefore automatic balancing technology becomes the gordian technique of such metal detection machine.

The automatic balancing technology scheme such as the United States Patent (USP) of present main flow.The patent No. 5,691,640 titles: " Forced Balance Metal Detector ", " automatic balance type metal detection machine ".This metal detection machine is exported two DC voltages through two digital to analog converters (D/A) after adopting balance detection to be compensated numerical value; The DC voltage of output and the sine wave of quadrature modulate two sine waves that are used to compensate through two multipliers; Give receiving circuit after these two sine waves are synthetic, compensation destroys the amplitude and the phase place of output because of balance.

Such scheme has adopted many mimic channels, causes the difficulty of complex circuit and debugging and because the problem of circuit itself causes problems such as stable reduction.

Summary of the invention

The object of the invention is exactly self-poise information processing method and the device that provides in order to overcome the defective that above-mentioned prior art exists in a kind of metallic foreign body machines that improves metal detection machine sensitivity and stability.

The object of the invention can be realized through following technical scheme:

Self-poise information processing method in a kind of metallic foreign body machines is characterized in that, may further comprise the steps:

1) start back A/D sample circuit is gathered the receiving phase φ of receiving circuit in real time ₁The amplitude A of information and the initial reception signal that obtains by receiving circuit, and detect the initial equilibrium state that receives signal automatically;

2) judge whether this equilibrium state satisfies setting value, if yes, do not produce balanced signal, if deny execution in step 3);

3) the initial equilibrium state that receives signal of basis is come the phase place and the amplitude of automatic setting balanced signal;

4) balanced signal is mixed with the initial signal that receives, mixed signal is delivered to back level signal processing circuit handle;

5) equilibrium state to mixed signal detects, and returns step 2);

6) judge whether manually to change the phase place that transmits, if yes, return step 1), if not, return step 5).

Self-poise signal conditioning package in a kind of metallic foreign body machines; It is characterized in that; Comprise receiving circuit, filtering circuit, A/D sample circuit, real-time phase computing module, balanced signal generation module, FPGA, DSP, MCU, balance Control Scheme device, D/A modular converter, radiating circuit; Described receiving circuit, balance Control Scheme device, filtering circuit, A/D sample circuit connect successively; Described A/D sample circuit is connected with real-time phase computing module, FPGA respectively; Described FPGA is connected with real-time phase computing module, DSP, balanced signal generation module respectively, and described FPGA links to each other with the balance Control Scheme device through the balance Control Scheme bus, and described FPGA is connected with radiating circuit through the D/A modular converter; Described DSP is connected with MCU, and described balanced signal generation module is connected with the balance Control Scheme device.

Compared with prior art, the present invention has the following advantages:

1, adopt brand-new DSP+FPGA framework, constituted system for real-time signal processing, according to lower layer signal and highest level signal different features, the rational division of labor of DSP and FPGA having been made data processing;

2, the accuracy of detection and the stability of complete machine have been improved to a great extent; The ageing resistance and the adaptive capacity to environment of metal detection machine have been improved simultaneously; And then significantly improved life-span of metal detection machine; Simultaneously, the framework of DSP+FPGA makes that also metal detection machine performance improvement, function expansion and system upgrade become convenient in the future.

Description of drawings

Fig. 1 is a process flow diagram of the present invention;

Fig. 2 is a structural representation of the present invention.

Embodiment

Below in conjunction with accompanying drawing and specific embodiment the present invention is elaborated.

Embodiment

Emphasis of the present invention improves shortcoming of the prior art.

At first in the ultimate principle of phase-detection, find its inherent defect, as follows:

Suppose that transmitting coil is output as u=a*sin (ω t+ θ), receiving coil is output as Uo=Asin (ω t+ φ), transmits in theory to produce fixing phase difference-θ through radiating circuit and receiving circuit, and hereinafter this phase differential is represented with α.Two orthogonal sinusoidal waves that are input as same frequency of modulation are respectively Us=Bsin ω t and Uc=Bsin (ω t+90).

Be respectively through output behind the multiplier:

Ur＝Uo*Us＝Asin(ωt+φ)*Bsinωt＝AB/2[cosφ-cos(2ωt+φ)]

Ux＝Uo*Uc＝Asin(ωt+φ)*Bsin(ωt+90)＝AB/2[sinφ+sin(2ωt+φ)]

Through after the low-pass filter, radio-frequency component is filtered, and is output as:

Ur＝AB/2cosφ

Ux＝AB/2sinφ

Because B is the may command constant,, the size of Ur and Ux receives φ and amplitude A so being decided by phase place.Research shows that different objects is through different to the influence of probe internal magnetic field after the machines; The size that needs only pre-set transmitter, phase θ for different products to be detected just can suppress the signal of product; Give prominence to the signal of metal object, thereby can realize detecting the function of metallic foreign body.Only need the size of monitoring Ur and two D. C. values of Ux, just can initially be received the amplitude and the phase information of signal.

Amplitude is:

A_{0} = \sqrt{} (U_{x}^{2} + U_{r}^{2})

Phase place is: φ=arctan (Ux/Ur)

Content of the present invention is exactly initially to receive the amplitude A o of signal and the numerical value of phase through real-time monitoring; Reach the purpose of real-time monitoring assembled machine balance state; Bigger as if initial reception signal amplitude, then need in FPGA, to generate a balanced signal and reach the self balancing purpose of reception signal through the balance Control Scheme device.

The present invention generates a new balanced signal Uoi=Ao*sin (ω t+ φ) through real-time detected Ao and φ, can infinitely approach initial reception signal Uo=Asin (ω t+ φ) on this signal theory, after both subtract each other, is zero in theory.In engineering practice, the value after subtracting each other just can improve the accuracy of detection of complete machine less than 500mV.

As shown in Figure 1, the self-poise information processing method in a kind of metallic foreign body machines may further comprise the steps:

5) equilibrium state to mixed signal detects, and returns step 2);

As shown in Figure 2; Self-poise signal conditioning package in a kind of metallic foreign body machines; Comprise receiving circuit 1, filtering circuit 11, A/D sample circuit 2, real-time phase computing module 3, balanced signal generation module 9, FPGA4, DSP5, MCU6, balance Control Scheme device 7, D/A modular converter, radiating circuit 8; Described receiving circuit 1, balance Control Scheme device 7, filtering circuit 11, A/D sample circuit 2 connect successively; Described A/D sample circuit 2 is connected with real-time phase computing module 3, FPGA4 respectively; Described FPGA4 is connected with real-time phase computing module 3, DSP5, balanced signal generation module 9 respectively, and described FPGA4 links to each other with balance Control Scheme device 7 through balance Control Scheme bus 10, and described FPGA4 is connected with radiating circuit 8 through the D/A modular converter; Described DSP5 is connected with MCU6, and described balanced signal generation module 9 is connected with balance Control Scheme device 7.

Claims

1. the self-poise information processing method in the metallic foreign body machines is characterized in that, may further comprise the steps:

5) equilibrium state to mixed signal detects, and returns step 2);

2. the self-poise signal conditioning package in the metallic foreign body machines; It is characterized in that; Comprise receiving circuit, filtering circuit, A/D sample circuit, real-time phase computing module, balanced signal generation module, FPGA, DSP, MCU, balance Control Scheme device, D/A modular converter, radiating circuit; Described receiving circuit, balance Control Scheme device, filtering circuit, A/D sample circuit connect successively; Described A/D sample circuit is connected with real-time phase computing module, FPGA respectively; Described FPGA is connected with real-time phase computing module, DSP, balanced signal generation module respectively, and described FPGA links to each other with the balance Control Scheme device through the balance Control Scheme bus, and described FPGA is connected with radiating circuit through the D/A modular converter; Described DSP is connected with MCU, and described balanced signal generation module is connected with the balance Control Scheme device.