Electric permanent magnetic chuck magnetic field detection system

Abstract

The invention discloses an electric permanent magnetic chuck magnetic field detection system, which adopts a plurality of magnetic field detection coils, a signal generation circuit and a signal processing circuit, and is characterized in that the signal generation circuit is used for generating a driving signal to drive the magnetic field detection coils; the magnetic field detection coil is used for receiving the driving signal generated by the signal generation circuit, detecting the magnetic field condition in the suction cup under the driving of the driving signal, generating a frequency value corresponding to the intensity change of the magnetic field in the suction cup, and feeding back the frequency value to the signal processing circuit; and the signal processing circuit is used for calculating the magnetic field intensity of the current electric permanent magnetic chuck according to the driving signal generated by the signal generation circuit and the frequency value fed back by the magnetic field detection coil. A traditional Hall sensor is replaced by the pre-embedded magnetic field detection coil, so that the problem that the Hall sensor is easy to damage and cannot be replaced is effectively solved; the internal magnetic field intensity value of the electro-permanent magnetic chuck can be detected in real time, and the safety and reliability of the electro-permanent magnetic chuck in the lifting process are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of electric permanent magnets, and in particular discloses an electric permanent magnet chuck magnetic field detection system. Background Art

[0002] There are two ways to detect the magnetic field of a traditional permanent magnetic chuck. Method 1: Use a magnetic field measurement tool (such as a Gauss meter) to measure the magnetic field strength on the surface of the magnetic pole. Method 2: Pre-embed a Hall sensor (here the detection coil is embedded) inside one or more magnetic poles to measure the magnetic field strength of the fixed magnetic pole. However, neither Method 1 nor Method 2 can detect the magnetic field strength of all magnetic poles of the permanent magnetic chuck in real time, and cannot monitor the working status of the permanent magnetic chuck. In addition, the pre-embedded Hall sensor is easily damaged and cannot be replaced.

[0003] Therefore, the above-mentioned defects existing in the existing magnetic field detection method of the electro-permanent magnetic chuck are technical problems that need to be solved urgently. Summary of the invention

[0004] The present invention provides a magnetic field detection system for an electric permanent magnetic chuck, aiming to solve at least one of the above-mentioned defects existing in the existing magnetic field detection method for an electric permanent magnetic chuck.

[0005] The present invention provides a magnetic field detection system for an electric permanent magnetic chuck, comprising a plurality of magnetic field detection coils, a signal generating circuit and a signal processing circuit, wherein: A signal generating circuit is connected to the magnetic field detection coil and is used to generate a driving signal to drive the magnetic field detection coil; The magnetic field detection coil is pre-buried inside the magnetic pole and connected to the signal generating circuit, and is used to receive the driving signal generated by the signal generating circuit. Under the drive of the driving signal, the magnetic field inside the suction cup is detected, a frequency value corresponding to the intensity change of the magnetic field inside the suction cup is generated, and the frequency value is fed back to the signal processing circuit; The signal processing circuit is connected to the magnetic field detection coil and the signal generating circuit respectively, and is used to calculate the magnetic field strength of the current electro-permanent magnetic chuck according to the driving signal generated by the signal generating circuit and the frequency value fed back by the magnetic field detection coil; The signal processing circuit includes a signal conversion circuit, a frequency voltage conversion circuit, a voltage current conversion circuit, a current voltage conversion circuit, an RC filter circuit, a coupling and voltage configuration circuit, a follower circuit and a current expansion circuit which are connected in sequence.

[0006] Furthermore, the signal generating circuit includes an oscillation circuit, and the oscillation circuit is used to generate a sinusoidal wave signal.

[0007] Further, the oscillation circuit includes an LC frequency selection circuit, a feedback circuit and a constant current circuit; LC frequency selection circuit, used to generate an oscillation signal of a set interval frequency; A feedback circuit is connected to the LC frequency selection circuit and is used to feed back the oscillation signal generated by the LC frequency selection circuit to the constant current circuit; The constant current circuit is connected to the feedback circuit and is used for receiving the oscillation signal fed back from the feedback circuit and providing a constant current to drive the magnetic field detection coil.

[0008] Furthermore, the LC frequency selection circuit includes a first capacitor, which is connected to the magnetic field detection coil through an inductor coil interface; the feedback circuit includes a first resistor and a second capacitor, which is connected to the second capacitor.

[0009] Furthermore, the constant current circuit includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first triode and a second triode, the base of the first triode is connected to the operating voltage through the second resistor, the base of the first triode is grounded through the third resistor, the collector of the first triode is connected to the ground, and the radiation pole of the first triode is connected to the operating voltage through the fourth resistor; the base of the second triode is connected to the operating voltage through the fifth resistor, the base of the second triode is grounded through the sixth resistor, the collector of the second triode is connected to the LC frequency selection circuit, and the radiation pole of the second triode is connected to the operating voltage through the fourth resistor.

[0010] Furthermore, the signal conversion circuit includes a seventh resistor and a voltage comparator, the positive input terminal of the voltage comparator is connected to the seventh resistor, the negative input terminal of the voltage comparator is connected to the ground, and the output terminal of the voltage comparator is connected to the signal processing circuit.

[0011] Further, the signal conversion circuit is connected to the oscillation circuit and is used to convert the sine wave signal generated by the oscillation circuit into a square wave signal; A frequency-to-voltage conversion circuit, connected to the signal conversion circuit, for converting the square wave signal into a first voltage signal; A voltage-to-current conversion circuit, connected to the frequency-to-voltage conversion circuit, and configured to convert the first voltage signal into a first current signal; A current-to-voltage conversion circuit, connected to the voltage-to-current conversion circuit, for converting the first current signal into a second voltage signal; an RC filter circuit, connected to the current-voltage conversion circuit, for filtering out a specific frequency component in the second voltage signal; A coupling and voltage configuration circuit, connected to the RC filter circuit, for converting the second voltage signal with the specific frequency component filtered out into a third voltage signal; The follower circuits are respectively connected to the voltage-frequency comparator circuits and are used to isolate the third voltage signal; The current expansion circuit is connected to the follower circuit and is used to expand the third voltage signal isolated by the follower circuit and output a second current signal.

[0012] Furthermore, the frequency-voltage conversion circuit and the voltage-current conversion circuit are integrated in the frequency-voltage conversion chip, the sixth pin of the frequency-voltage conversion chip is connected to the voltage comparator, and the first pin of the frequency-voltage conversion chip is connected to the voltage-current conversion circuit; the current-voltage conversion circuit includes an eighth resistor and a third capacitor, one end of the eighth resistor connected in parallel with the third capacitor is connected to the first pin of the frequency-voltage conversion chip, and the other end of the eighth resistor connected in parallel with the third capacitor is grounded.

[0013] Furthermore, the RC filter circuit includes a ninth resistor and a fourth capacitor, the fifth pin of the frequency-voltage conversion chip is connected to the working voltage through the ninth resistor, and the fifth pin of the frequency-voltage conversion chip is grounded through the fourth capacitor; the coupling and voltage configuration circuit includes a fifth capacitor, a tenth resistor and an eleventh resistor, the fifth capacitor is connected to the sixth pin of the frequency-voltage conversion chip, and the seventh pin of the frequency-voltage conversion chip is divided into two paths, one path is connected to the working voltage through the tenth resistor, and the other path is grounded through the eleventh resistor.

[0014] Further, the follower circuit includes an operational amplifier, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a sixth capacitor, a seventh capacitor and a first field effect transistor, the operational amplifier includes a first operational amplifier unit and a second operational amplifier unit, the positive input terminal of the first operational amplifier unit is connected to the twelfth resistor, the input terminal of the first operational amplifier unit is grounded through the thirteenth resistor, the output terminal of the first operational amplifier unit is divided into two paths, one path is connected to the gate of the first field effect transistor through the fourteenth resistor, and the other path is connected to the source of the first field effect transistor through the sixth capacitor, and the drain of the first field effect transistor is connected to the positive input terminal of the second operational amplifier unit; The positive input terminal of the second operational amplifier unit is connected to the working power supply through the fifteenth resistor, the negative input terminal of the second operational amplifier unit is connected to the working power supply through the sixteenth resistor, and the output terminal of the second operational amplifier unit is divided into two paths, one path is connected to the current expansion circuit, and the other path is connected to the working power supply through the seventh capacitor and the sixteenth resistor connected in series; the current expansion circuit includes a seventeenth resistor, an eighteenth resistor and a second field effect transistor, the gate of the second field effect transistor is connected to the output terminal of the second operational amplifier unit through the seventeenth resistor, the source of the second field effect transistor is connected to the output terminal of the second operational amplifier unit through the seventh capacitor, and the drain of the second field effect transistor is connected to the eighteenth resistor.

[0015] The beneficial effects achieved by the present invention are: The present invention provides a magnetic field detection system for an electric permanent magnetic chuck, which adopts a plurality of magnetic field detection coils, a signal generating circuit and a signal processing circuit. The signal generating circuit is used to generate a driving signal to drive the magnetic field detection coil; the magnetic field detection coil is used to receive the driving signal generated by the signal generating circuit, and under the drive of the driving signal, detect the magnetic field inside the chuck, generate a frequency value corresponding to the intensity change of the magnetic field inside the chuck, and feed the frequency value back to the signal processing circuit; the signal processing circuit is used to calculate the magnetic field intensity of the current electric permanent magnetic chuck according to the driving signal generated by the signal generating circuit and the frequency value fed back by the magnetic field detection coil. The signal processing circuit includes a signal conversion circuit, a frequency voltage conversion circuit, a voltage current conversion circuit, a current voltage conversion circuit, an RC filter circuit, a coupling and voltage configuration circuit, a follower circuit and a current expansion circuit connected in sequence. The electric permanent magnetic chuck magnetic field detection system provided by the present invention replaces the traditional Hall sensor with a pre-buried magnetic field detection coil, thereby effectively solving the problem that the Hall sensor is easily damaged and cannot be replaced; the system can solve the problem that the strength of the electric permanent magnetic chuck magnetic field cannot be detected in real time using an external magnetic field detection tool, and the detection is convenient, accurate and real-time; through the use of the system, the internal magnetic field strength value of the electric permanent magnetic chuck can be detected in real time, ensuring the safety and reliability of the electric permanent magnetic chuck during lifting. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a functional block diagram of an embodiment of an electric permanent magnetic chuck magnetic field detection system of the present invention; Figure 2 The present invention is a circuit diagram of an embodiment of an electro-permanent magnetic chuck magnetic field detection system.

[0017] Description of Figure Numbers: 10. Magnetic field detection coil; 20. Signal generating circuit; 30. Signal processing circuit; 40. Power supply circuit. DETAILED DESCRIPTION

[0018] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0019] like Figure 1 and Figure 2As shown, the first embodiment of the present invention proposes a magnetic field detection system for an electric permanent magnetic chuck, comprising a plurality of magnetic field detection coils 10, a signal generating circuit 20 and a signal processing circuit 30, wherein the signal generating circuit 20 is connected to the magnetic field detection coil 10, and is used to generate a driving signal to drive the magnetic field detection coil 10; the magnetic field detection coil 10 is pre-buried inside the magnetic pole, connected to the signal generating circuit 20, and is used to receive the driving signal generated by the signal generating circuit 20, and under the drive of the driving signal, detects the magnetic field inside the chuck, generates a frequency value corresponding to the intensity change of the magnetic field inside the chuck, and feeds the frequency value back to the signal processing circuit 30; the signal processing circuit 30 is respectively connected to the magnetic field detection coil 10 and the signal generating circuit 20, and is used to calculate the magnetic field intensity of the current electric permanent magnetic chuck according to the driving signal generated by the signal generating circuit 20 and the frequency value fed back by the magnetic field detection coil 10. The signal processing circuit 30 includes a signal conversion circuit, a frequency voltage conversion circuit, a voltage current conversion circuit, a current voltage conversion circuit, an RC filter circuit, a coupling and voltage configuration circuit, a follower circuit and a current expansion circuit connected in sequence. In this embodiment, the signal generating circuit 20 and the signal processing circuit 30 may use existing functional module circuits, for example, the signal generating circuit 20 may use a sine wave oscillator, a multivibrator, a square wave generator, a sawtooth wave generator or a triangle wave generator, etc. The signal processing circuit 30 may use a filter, an amplifier circuit, a modulation and demodulation circuit, an analog-to-digital conversion circuit, a detection circuit, an oscillation circuit or a comparison circuit, etc., all of which are within the protection scope of this patent.

[0020] Further, see Figure 1 and Figure 2 , the electric permanent magnetic chuck magnetic field detection system provided in this embodiment, the signal generating circuit 20 includes an oscillation circuit, wherein the oscillation circuit is used to generate a sine wave signal. Specifically, the oscillation circuit includes an LC frequency selection circuit, a feedback circuit and a constant current circuit, wherein the LC frequency selection circuit is used to generate an oscillation signal of a set interval frequency; the feedback circuit is connected to the LC frequency selection circuit, and is used to feed back the oscillation signal generated by the LC frequency selection circuit to the constant current circuit; the constant current circuit is connected to the feedback circuit, and is used to receive the oscillation signal fed back by the feedback circuit, and provide a constant current to drive the magnetic field detection coil 10. The electric permanent magnetic chuck magnetic field detection system provided in this embodiment can solve the problem that the strength of the electric permanent magnetic chuck magnetic field cannot be detected in real time using an external magnetic field detection tool, and the detection is convenient, accurate and real-time; through the use of this system, the internal magnetic field strength value of the electric permanent magnetic chuck can be detected in real time, ensuring the safety and reliability of the electric permanent magnetic chuck during lifting.

[0021] Preferably, see Figure 1 and Figure 2In the electric permanent magnetic chuck magnetic field detection system provided in this embodiment, the LC frequency selection circuit includes a first capacitor C5 and an external coil, and the first capacitor C5 is connected to the external coil through the inductor coil interface P1; the feedback circuit includes a first resistor R14 and a second capacitor C3, and the first resistor R14 is connected to the second capacitor C3. The constant current circuit includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first transistor Q1 and a second transistor Q2. The base of the first transistor Q1 is connected to the working voltage +5V through the second resistor R2, the base of the first transistor Q1 is grounded through the third resistor R11, the collector of the first transistor is connected to the ground GND, and the radiation of the first transistor Q1 is connected to the working voltage +5V through the fourth resistor R1; the base of the second transistor Q2 is connected to the working voltage +5V through the fifth resistor R3, the base of the second transistor Q2 is grounded through the sixth resistor R12, the collector of the second transistor Q2 is connected to the LC frequency selection circuit, and the radiation of the second transistor is connected to the working voltage +5V through the fourth resistor R1. The transistor Q1, the resistor R2, the resistor R11 and the resistor R1 form a constant current circuit. The transistor Q2, the resistor R3 and the resistor R12 provide a constant 1.8mA current for the coil to drive the coil. Capacitor C5 and the external coil form an LC frequency selection circuit, and the oscillation signal is fed back to transistor Q1 through resistor R14 and capacitor C3, thereby obtaining a stable oscillation feedback circuit. The electric permanent magnetic chuck magnetic field detection system provided in this embodiment can detect the internal magnetic field strength value of the electric permanent magnetic chuck in real time, ensuring the safety and reliability of the electric permanent magnetic chuck during lifting.

[0022] Further, see Figure 1 and Figure 2In the electric permanent magnetic chuck magnetic field detection system provided in this embodiment, the signal conversion circuit includes a seventh resistor R6 and a voltage comparator U1A, the positive input terminal of the voltage comparator U1A is connected to the seventh resistor R6, the negative input terminal of the voltage comparator U1A is connected to the ground GND, and the output terminal of the voltage comparator U1A is connected to the signal processing circuit 30. In this embodiment, the model of the voltage comparator U1A is LM393. LM393 converts the sine wave signal into a square wave signal for subsequent processing. A frequency-voltage conversion circuit is used to convert a square wave signal into a first voltage signal; a voltage-current conversion circuit is connected to the frequency-voltage conversion circuit and is used to convert a first voltage signal into a first current signal; a current-voltage conversion circuit is connected to the voltage-current conversion circuit and is used to convert a first current signal into a second voltage signal; an RC filter circuit is connected to the current-voltage conversion circuit and is used to filter out specific frequency components in the second voltage signal; a coupling and voltage configuration circuit is connected to the RC filter circuit and is used to convert the second voltage signal from which specific frequency components are filtered out into a third voltage signal; a follower circuit is respectively connected to the voltage-frequency comparator circuit and is used to isolate the third voltage signal; a current expansion circuit is connected to the follower circuit and is used to expand the third voltage signal isolated by the follower circuit and output a second current signal.

[0023] Specifically, see Figure 1 and Figure 2 In the electric permanent magnetic chuck magnetic field detection system provided in this embodiment, the frequency-voltage conversion circuit and the voltage-current conversion circuit are integrated in the frequency-voltage conversion chip U2, the sixth pin of the frequency-voltage conversion chip U2 is connected to the voltage comparator U1A, and the first pin of the frequency-voltage conversion chip U2 is connected to the voltage-current conversion circuit; the current-voltage conversion circuit includes an eighth resistor R5 and a third capacitor C1, one end of the eighth resistor R5 connected in parallel with the third capacitor C1 is connected to the first pin of the frequency-voltage conversion chip U2, and the other end of the eighth resistor R5 connected in parallel with the third capacitor C1 is grounded GND. In this embodiment, the model used by the frequency-voltage conversion chip U2 is LM331. LM331 is an F / V conversion chip, which inputs the obtained square wave signal through pin 6 and converts the square wave signal into a corresponding current and outputs it from pin 1.

[0024] Further, see Figure 1 and Figure 2, the electric permanent magnetic chuck magnetic field detection system provided in this embodiment, the RC filter circuit includes a ninth resistor R15 and a fourth capacitor C4, the fifth pin of the frequency voltage conversion chip U2 is connected to the working voltage +5V through the ninth resistor, and the fifth pin of the frequency voltage conversion chip is grounded through the fourth capacitor; the coupling and voltage configuration circuit includes a fifth capacitor C2, a tenth resistor R7 and an eleventh resistor R8, the fifth capacitor is connected to the sixth pin of the frequency voltage conversion chip, and the seventh pin of the frequency voltage conversion chip is divided into two paths, one is connected to the working voltage through the tenth resistor, and the other is grounded through the eleventh resistor. In this embodiment, the resistor R5 and the capacitor C1 convert the output current signal into a voltage signal, thereby converting the square wave signal into a voltage value. The resistor R15 and the capacitor C4 are the RC filter circuit of LM331, the capacitor C2 is the input coupling capacitor, and the resistor R7 and the resistor R8 are the input voltage configuration resistors of the LM331 comparator.

[0025] Preferably, see Figure 1 and Figure 2The electric permanent magnetic chuck magnetic field detection system provided in this embodiment, the follower circuit includes an operational amplifier U4, a twelfth resistor R22, a thirteenth resistor R26, a fourteenth resistor R23, a fifteenth resistor R17, a sixteenth resistor R16, a sixth capacitor C14, a seventh capacitor C7 and a first field effect transistor Q4, the operational amplifier U4 includes a first operational amplifier unit U4B and a second operational amplifier unit U4A, the positive input end of the first operational amplifier unit is connected to the twelfth resistor, the input end of the first operational amplifier unit is grounded through the thirteenth resistor, the output end of the first operational amplifier unit is divided into two paths, one path is connected to the gate of the first field effect transistor through the fourteenth resistor, and the other path is connected to the source of the first field effect transistor through the sixth capacitor C14, and the drain of the first field effect transistor is connected to the The positive input terminal of the second operational amplifier unit U4A is connected; the positive input terminal of the second operational amplifier unit is connected to the working power supply +24V through the fifteenth resistor, the negative input terminal of the second operational amplifier unit is connected to the working power supply through the sixteenth resistor, and the output terminal of the second operational amplifier unit is divided into two paths, one is connected to the current expansion circuit, and the other is connected to the working power supply after the seventh capacitor and the sixteenth resistor are connected in series; the current expansion circuit includes the seventeenth resistor R19, the eighteenth resistor R25 and the second field effect tube Q3, the gate of the second field effect tube is connected to the output terminal of the second operational amplifier unit through the seventeenth resistor, the source of the second field effect tube is connected to the output terminal of the second operational amplifier unit through the seventh capacitor, and the drain of the second field effect tube is connected to the eighteenth resistor. In this embodiment, the model of the operational amplifier U4 is LT1490A. The voltage signal output from LM331 is sent to the 4~20mA circuit composed of LT1490A. The input voltage signal is maintained by the follower circuit of LT1490A and expanded by field effect tube Q4, generating a 1~5mA current signal on resistor R26. Resistors R17, R16 and LT1490A convert the current signal through resistors R17 and R26 into a 4~20mA current signal, and expand the current to the outside through field effect tube Q3. Resistor R25 is a 4~20mA external output current limiting resistor, and diodes D2 and D3 are output port protection diodes.

[0026] like Figure 1 and Figure 2 As shown, the working principle of the electric permanent magnetic chuck magnetic field detection system provided in this embodiment is as follows: The magnetic field detection coil 10 is wound with ordinary enameled wire, with 50 turns, and is used to detect the magnetic field inside the suction cup. When the magnetic field inside the suction cup changes, the frequency of the signal sensed by the magnetic field detection coil 10 changes.

[0027] The signal generating circuit is composed of an oscillating circuit. Transistor Q1, resistor R2, resistor R11 and resistor R1 form a constant current circuit. Transistor Q2, resistor R3 and resistor R12 provide a constant 1.8mA current for the coil to drive the coil. Capacitor C5 and the external coil form an LC frequency selection circuit, and the oscillation signal is fed back to transistor Q1 through resistor R14 and capacitor C3, thereby obtaining a stable oscillation feedback circuit.

[0028] The oscillation signal generated by the above circuit is a sine wave signal, and LM393 is used to convert the sine wave signal into a square wave signal for subsequent processing.

[0029] LM331 is an F / V conversion chip, which inputs the obtained square wave signal through pin 6 and converts the square wave signal into the corresponding current and outputs it from pin 1. Resistor R5 and capacitor C1 convert the output current signal into a voltage signal, thereby converting the square wave signal into a voltage value. Resistor R15 and capacitor C4 are the RC filter circuit of LM331, capacitor C2 is the input coupling capacitor, and resistors R7 and R8 are the LM331 comparator input voltage configuration resistors.

[0030] The voltage signal output from LM331 is sent to the 4~20mA circuit composed of LT1490A. The input voltage signal is maintained by the follower circuit of LT1490A and expanded through the field effect tube Q4, generating a 1~5mA current signal on the resistor R26. Resistors R17, R16 and LT1490A convert the current signal through resistors R17 and R26 into a 4~20mA current signal, and expand the current through the field effect tube Q3 for external output. Resistor R25 is a 4~20mA external output current limiting resistor, and diodes D2 and D3 are output port protection diodes.

[0031] The power supply circuit 40 provides the required operating voltage for the signal generating circuit 20 and the signal processing circuit 30 .

[0032] The power supply circuit 40 converts the external input voltage of 10V~36V into 5V voltage for use by the signal generating circuit and the signal processing circuit. Capacitors C9, C10 and C11 are input filter capacitors, resistors R18 and R21 are input voltage detection resistors, and resistors R20 and R24 are output voltage configuration resistors. Finally, the input voltage of 10V~36V is converted into 5V voltage.

[0033] The working principle of this embodiment is: the driving signal generated by the signal generating circuit is used to drive the magnetic field detection coil. When the magnetic field detection coil is driven by the driving signal, the frequency value generated by the magnetic field detection coil will change with the change of the intensity of the magnetic field. The signal processing circuit calculates the current magnetic field intensity of the electro-permanent magnetic chuck according to the frequency value fed back by the magnetic field detection coil, thereby achieving the purpose of real-time detection.

[0034] This embodiment needs to be debugged after installation, and a two-point calibration is performed on the frequency value of the coil and the magnetic field strength of the suction cup.

[0035] The device is powered on, and the permanent magnetic chuck is in the demagnetized state. The current value corresponding to the current frequency is recorded, and the output current is adjusted to 4mA by adjusting the resistance values ​​of resistors R26 and R17.

[0036] Cover the workpiece with the permanent magnetic chuck and perform magnetization operation. The current value corresponding to the current frequency is recorded as the current value in the full magnetization state.

[0037] The present embodiment provides a magnetic field detection system for an electric permanent magnetic chuck. Compared with the prior art, the system adopts a plurality of magnetic field detection coils, a signal generating circuit and a signal processing circuit. The signal generating circuit is used to generate a driving signal to drive the magnetic field detection coil; the magnetic field detection coil is used to receive the driving signal generated by the signal generating circuit, and under the drive of the driving signal, detect the magnetic field inside the chuck, generate a frequency value corresponding to the intensity change of the magnetic field inside the chuck, and feed the frequency value back to the signal processing circuit; the signal processing circuit is used to calculate the magnetic field intensity of the current electric permanent magnetic chuck according to the driving signal generated by the signal generating circuit and the frequency value fed back by the magnetic field detection coil. The magnetic field detection system for an electric permanent magnetic chuck provided in the present embodiment replaces the traditional Hall sensor with a pre-buried magnetic field detection coil, which effectively solves the problem that the Hall sensor is easily damaged and cannot be replaced; the system can solve the problem that the strength of the magnetic field of the electric permanent magnetic chuck cannot be detected in real time using an external magnetic field detection tool, and the detection is convenient, accurate and real-time; through the use of the system, the internal magnetic field intensity value of the electric permanent magnetic chuck can be detected in real time, ensuring the safety and reliability of the electric permanent magnetic chuck during lifting.

[0038] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An electric permanent magnetic chuck magnetic field detection system, characterized in that: It comprises a plurality of magnetic field detection coils (10), a signal generating circuit (20) and a signal processing circuit (30), wherein: The signal generating circuit (20) is connected to the magnetic field detection coil (10) and is used to generate a driving signal to drive the magnetic field detection coil (10); The magnetic field detection coil (10) is pre-buried inside the magnetic pole and connected to the signal generating circuit (20), and is used to receive the driving signal generated by the signal generating circuit (20), and under the drive of the driving signal, detect the magnetic field inside the suction cup, generate a frequency value corresponding to the intensity change of the magnetic field inside the suction cup, and feed the frequency value back to the signal processing circuit (30); The signal processing circuit (30) is connected to the magnetic field detection coil (10) and the signal generating circuit (20) respectively, and is used to calculate the current magnetic field strength of the electro-permanent magnetic chuck according to the drive signal generated by the signal generating circuit (20) and the frequency value fed back by the magnetic field detection coil (10); The signal processing circuit (30) comprises a signal conversion circuit, a frequency voltage conversion circuit, a voltage current conversion circuit, a current voltage conversion circuit, an RC filter circuit, a coupling and voltage configuration circuit, a follower circuit and a current expansion circuit, which are connected in sequence.

2. The electric permanent magnetic chuck magnetic field detection system according to claim 1, characterized in that: The signal generating circuit (20) comprises an oscillating circuit, and the oscillating circuit is used to generate a sinusoidal wave signal.

3. The electric permanent magnetic chuck magnetic field detection system according to claim 2, characterized in that: The oscillation circuit includes an LC frequency selection circuit, a feedback circuit and a constant current circuit. The LC frequency selection circuit is used to generate an oscillation signal with a set interval frequency; The feedback circuit is connected to the LC frequency selection circuit and is used to feed back the oscillation signal generated by the LC frequency selection circuit to the constant current circuit; The constant current circuit is connected to the feedback circuit and is used to receive the oscillation signal fed back by the feedback circuit and provide a constant current to drive the magnetic field detection coil (10).

4. The electric permanent magnetic chuck magnetic field detection system as claimed in claim 3, characterized in that: The LC frequency selection circuit comprises a first capacitor, which is connected to the magnetic field detection coil (10) via an inductor coil interface; the feedback circuit comprises a first resistor and a second capacitor, which is connected to the second capacitor.

5. The electric permanent magnetic chuck magnetic field detection system as claimed in claim 3, characterized in that: The constant current circuit includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first triode and a second triode, wherein the base of the first triode is connected to the operating voltage through the second resistor, the base of the first triode is grounded through the third resistor, the collector of the first triode is connected to the ground, and the radiation electrode of the first triode is connected to the operating voltage through the fourth resistor; the base of the second triode is connected to the operating voltage through the fifth resistor, the base of the second triode is grounded through the sixth resistor, the collector of the second triode is connected to the LC frequency selection circuit, and the radiation electrode of the second triode is connected to the operating voltage through the fourth resistor.

6. The electric permanent magnetic chuck magnetic field detection system according to claim 3, characterized in that: The signal conversion circuit comprises a seventh resistor and a voltage comparator, the positive input terminal of the voltage comparator is connected to the seventh resistor, the negative input terminal of the voltage comparator is connected to the ground, and the output terminal of the voltage comparator is connected to the signal processing circuit (30).

7. The magnetic field detection system of the electric permanent magnetic chuck as claimed in claim 2, characterized in that: The signal conversion circuit is connected to the oscillation circuit and is used to convert the sine wave signal generated by the oscillation circuit into a square wave signal; The frequency-to-voltage conversion circuit is connected to the signal conversion circuit and is used to convert the square wave signal into a first voltage signal; The voltage-to-current conversion circuit is connected to the frequency-to-voltage conversion circuit and is used to convert the first voltage signal into a first current signal; The current-to-voltage conversion circuit is connected to the voltage-to-current conversion circuit and is used to convert the first current signal into a second voltage signal; The RC filter circuit is connected to the current-voltage conversion circuit and is used to filter out a specific frequency component in the second voltage signal; The coupling and voltage configuration circuit is connected to the RC filter circuit and is used to convert the second voltage signal with the specific frequency component filtered out into a third voltage signal; The follower circuits are respectively connected to the voltage-frequency comparator circuits and are used to isolate the third voltage signal; The current expansion circuit is connected to the follower circuit and is used to expand the third voltage signal isolated by the follower circuit and output a second current signal.

8. The electric permanent magnetic chuck magnetic field detection system according to claim 7, characterized in that: The frequency-voltage conversion circuit and the voltage-current conversion circuit are integrated in a frequency-voltage conversion chip, the sixth pin of the frequency-voltage conversion chip is connected to the voltage comparator, and the first pin of the frequency-voltage conversion chip is connected to the voltage-current conversion circuit; the current-voltage conversion circuit includes an eighth resistor and a third capacitor, one end of the eighth resistor connected in parallel with the third capacitor is connected to the first pin of the frequency-voltage conversion chip, and the other end of the eighth resistor connected in parallel with the third capacitor is grounded.

9. The electric permanent magnetic chuck magnetic field detection system according to claim 8, characterized in that: The RC filter circuit includes a ninth resistor and a fourth capacitor, the fifth pin of the frequency-voltage conversion chip is connected to the working voltage through the ninth resistor, and the fifth pin of the frequency-voltage conversion chip is grounded through the fourth capacitor; the coupling and voltage configuration circuit includes a fifth capacitor, a tenth resistor and an eleventh resistor, the fifth capacitor is connected to the sixth pin of the frequency-voltage conversion chip, and the seventh pin of the frequency-voltage conversion chip is divided into two paths, one path is connected to the working voltage through the tenth resistor, and the other path is grounded through the eleventh resistor.

10. The electric permanent magnetic chuck magnetic field detection system according to claim 9, characterized in that: The follower circuit includes an operational amplifier, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a sixth capacitor, a seventh capacitor and a first field effect transistor. The operational amplifier includes a first operational amplifier unit and a second operational amplifier unit. The positive input terminal of the first operational amplifier unit is connected to the twelfth resistor, and the input terminal of the first operational amplifier unit is grounded through the thirteenth resistor. The output terminal of the first operational amplifier unit is divided into two paths, one path is connected to the gate of the first field effect transistor through the fourteenth resistor, and the other path is connected to the source of the first field effect transistor through the sixth capacitor. The drain of the first field effect transistor is connected to the positive input terminal of the second operational amplifier unit; The positive input terminal of the second operational amplifier unit is connected to the working power supply through the fifteenth resistor, the negative input terminal of the second operational amplifier unit is connected to the working power supply through the sixteenth resistor, and the output terminal of the second operational amplifier unit is divided into two paths, one path is connected to the current expansion circuit, and the other path is connected to the working power supply through the seventh capacitor and the sixteenth resistor connected in series; the current expansion circuit includes a seventeenth resistor, an eighteenth resistor and a second field effect transistor, the gate of the second field effect transistor is connected to the output terminal of the second operational amplifier unit through the seventeenth resistor, the source of the second field effect transistor is connected to the output terminal of the second operational amplifier unit through the seventh capacitor, and the drain of the second field effect transistor is connected to the eighteenth resistor.

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