Vibration device and method for vibrating sample magnetometer

Abstract

The present invention relates to a vibration device and method for a vibrating sample magnetometer, in which a linear voice coil motor is arranged in cooperation with a grating ruler; the signal output end of the grating ruler is connected to a microcontroller; the input end of a displacement signal source is electrically connected to the microcontroller; the input end of an AC signal source is electrically connected to the microcontroller; the output end of the AC signal source and the output end of the displacement signal source are both electrically connected to the input end of a differential amplifier; the input end of a DC signal source is electrically connected to the microcontroller, the output end of the DC signal source and the output end of the differential amplifier are both electrically connected to the input end of an adder, and the output end of the adder is electrically connected to the linear voice coil motor through a current source. The present invention uses a linear voice coil motor as a vibration source, and uses a closed-loop control combining digital and analog, so that the vibration frequency and amplitude are stable, and at the same time has small mass, large load capacity, simple and reliable control circuit, and technical indicators reach the level of foreign commercial instruments, which can replace imports.

Description

Technical Field

[0001] The invention relates to a vibrating sample magnetometer, and in particular to a vibration device and a vibration method of a vibrating sample magnetometer. Background Art

[0002] The vibrating sample magnetometer is a highly sensitive magnetic moment measuring instrument based on the principle of electromagnetic induction. The induced voltage generated by the vibration of the sample under test in the detection coil is proportional to the sample magnetic moment, amplitude, and vibration frequency. The magnetic moment of the sample to be tested can be calculated by measuring this voltage with a phase-locked amplifier on the basis of ensuring that the amplitude and vibration frequency remain unchanged. The vibration head is a key component in the vibrating sample magnetometer, and the stability of its amplitude and vibration frequency is crucial to the measurement results. At present, there are many commercial vibrating sample magnetometers at home and abroad. For example, the vibrating sample magnetometer of a foreign company uses a linear motor as a vibration source and adopts a digital closed-loop method to stabilize the sample vibration frequency and amplitude, and achieve good accuracy; but it is expensive, restricted by imports, and the vibration source is heavy. For example, the vibrating sample magnetometer of another foreign company uses a loudspeaker as a vibration source and adopts an analog closed-loop method to stabilize the sample vibration frequency and amplitude, and achieve good accuracy; but it is expensive, restricted by imports, and the vibration source is not used for a long time, and it must work in an open loop for a long time before it can work in a closed loop. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a vibration device and method for a vibrating sample magnetometer, which uses a linear voice coil motor as a vibration source and a closed-loop control combining digital and analog to stabilize the vibration frequency and amplitude. At the same time, the device has a small mass, a large load capacity, a simple and reliable control circuit, and technical indicators that reach the level of foreign commercial instruments and can replace imports.

[0004] The technical solution of the present invention to solve the above technical problems is as follows: a vibration device of a vibrating sample magnetometer, comprising a linear voice coil motor, a grating ruler, a microcontroller, a displacement signal source, an AC signal source, a differential amplifier, a DC signal source, an adder and a current source; the linear voice coil motor is arranged in conjunction with the grating ruler, and the grating ruler is used to detect the displacement of the output shaft of the linear voice coil motor vibrating up and down; the signal output end of the grating ruler is electrically connected to the input end of the microcontroller; the input end of the displacement signal source is electrically connected to the microcontroller, the input end of the AC signal source is electrically connected to the microcontroller, the output end of the AC signal source and the output end of the displacement signal source are both electrically connected to the input end of the differential amplifier; the input end of the DC signal source is electrically connected to the microcontroller, the output end of the DC signal source and the output end of the differential amplifier are both electrically connected to the input end of the adder, and the output end of the adder is electrically connected to the linear voice coil motor through the current source.

[0005] The beneficial effects of the present invention are as follows: in the vibration device of the present invention, a cylindrical linear voice coil motor is used as the vibration source, the linear voice coil motor works in an AC / DC superposition state, a grating ruler is used for displacement measurement, and the digital displacement signal collected by the grating ruler is supplied to the displacement signal source and converted into an analog displacement signal for analog feedback; a closed-loop control combining digital and analog is adopted, the analog displacement signal is an analog signal converted in real time from the digital displacement signal, the analog closed-loop circuit only performs AC signal feedback, and the DC signal is independently taken out to offset the weight of the linear voice coil motor mover, thereby making the vibration frequency and amplitude stable, and at the same time having small mass, large load capacity, simple and reliable control circuit, and technical indicators reaching the level of foreign commercial instruments, which can replace imports.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, it also includes a slide, the output shaft of the linear motor is connected to the slide and can vibrate up and down along the slide; the grating ruler is installed on the slide.

[0008] Furthermore, the difference amplifier is specifically a first-order integrator.

[0009] Based on the above-mentioned vibration device of a vibrating sample magnetometer, the present invention also provides a vibration method of a vibrating sample magnetometer.

[0010] A vibration method for a vibrating sample magnetometer, using a linear voice coil motor as a vibration source of the vibrating sample magnetometer, the vibration method comprising the following steps:

[0011] Providing a corresponding DC signal to the linear voice coil motor according to the gravity exerted on the linear voice coil motor mover, and placing the linear voice coil motor mover in a central equilibrium position through the DC signal;

[0012] The corresponding AC signal is set according to the preset vibration frequency and amplitude signal; the digital displacement signal of the linear voice coil motor rotor vibration is obtained at the same time, and converted into an analog displacement signal in real time;

[0013] Amplifying the difference between the AC signal and the analog displacement signal to output a differential AC signal;

[0014] The differential AC signal is superimposed on the DC signal to drive the linear voice coil motor mover to vibrate up and down at the center position.

[0015] The beneficial effects of the present invention are as follows: the vibration method of the present invention uses the linear voice coil motor as the vibration source of the vibrating sample magnetometer, and applies a DC signal to the linear voice coil motor to offset the gravity exerted on the linear voice coil motor mover, so that the linear voice coil motor mover is located at a central equilibrium position; the analog displacement signal is an analog signal converted in real time from a digital displacement signal, the analog closed-loop circuit only performs AC signal feedback, and adopts a closed-loop control combining digital and analog, so that the vibration frequency and amplitude are stable, and at the same time, the vibration method has small mass, large load capacity, simple and reliable control circuit, and technical indicators reach the level of foreign commercial instruments, which can replace imports.

[0016] Based on the above technical solution, the present invention can also be improved as follows.

[0017] Furthermore, the DC signal is specifically a DC voltage signal; the linear voice coil motor mover is placed in a central equilibrium position by using the DC signal, specifically including converting the DC signal from a DC voltage signal into a DC current signal, inputting the DC current signal into the linear voice coil motor, and driving the linear voice coil motor mover to be in a central equilibrium position.

[0018] Further, the AC signal is specifically an AC voltage signal; the differential AC signal is superimposed on the DC signal to drive the linear voice coil motor mover to vibrate up and down at the center position, specifically including:

[0019] The differential AC signal is superimposed on the DC signal to obtain an AC-DC mixed voltage signal, the AC-DC mixed voltage signal is converted into an AC-DC mixed current signal, and the AC-DC mixed current signal is input into the linear voice coil motor to drive the linear voice coil motor rotor to vibrate up and down at the center position. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a vibration device of a vibrating sample magnetometer of the present invention;

[0021] Figure 2 The present invention is a flow chart of a vibration method of a vibrating sample magnetometer.

[0022] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0023] 1. Linear voice coil motor, 2. Grating ruler, 3. Slide table. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0025] like Figure 1As shown, a vibration device of a vibrating sample magnetometer includes a linear voice coil motor 1, a grating ruler 2, a microcontroller, a displacement signal source, an AC signal source, a differential amplifier, a DC signal source, an adder and a current source; the linear voice coil motor 1 is arranged in conjunction with the grating ruler 2, and the grating ruler 2 is used to detect the displacement of the output shaft of the linear voice coil motor 1 when it vibrates up and down; the signal output end of the grating ruler 2 is electrically connected to the input end of the microcontroller; the input end of the displacement signal source is electrically connected to the microcontroller; the input end of the AC signal source is electrically connected to the microcontroller, and the output end of the AC signal source and the output end of the displacement signal source are both electrically connected to the input end of the differential amplifier; the input end of the DC signal source is electrically connected to the microcontroller, and the output end of the DC signal source and the output end of the differential amplifier are both electrically connected to the input end of the adder, and the output end of the adder is electrically connected to the linear voice coil motor 1 through the current source.

[0026] In this specific embodiment:

[0027] Preferably, the vibration device further includes a slide 3 , the output shaft of the linear motor 1 is connected to the slide 3 , and can vibrate up and down along the slide 3 ; the grating ruler 2 is mounted on the slide 3 .

[0028] Preferably, the difference amplifier is specifically a first-order integrator.

[0029] The working principle of the vibration device of the present invention is that the microcontroller (32-bit ARM chip) is the control center. First, the microcontroller controls the DC signal source to send a DC signal, so that the linear voice coil motor mover (voice coil winding and winding bracket) is in the central balance position (due to the gravity of the linear voice coil motor mover, the mover is located at the bottom); the microcontroller sets the AC signal source according to the given frequency and amplitude signal, and controls the AC signal source to provide the corresponding AC signal. The microcontroller receives the digital displacement signal of the grating ruler and converts it into an analog displacement signal in real time using the displacement signal source. The AC signal provided by the AC signal source and the analog displacement signal are amplified by a differential amplifier (first-order integrator) to output a differential AC signal. The differential AC signal is superimposed on the DC signal provided by the DC signal source and the voltage is converted into a current through a current source, driving the linear voice coil motor mover to vibrate up and down along the slide at the center position.

[0030] When the entire vibration system works stably, the frequency and amplitude of the AC signal provided by the AC signal source are equal to the analog displacement signal, so as long as the amplitude and frequency of the AC signal provided by the AC signal source are stable, the amplitude and frequency of the vibration of the linear voice coil motor rotor can be guaranteed to be stable.

[0031] In order to ensure the stable operation of the entire vibration system, the most important thing is the design of the analog closed loop. The vibrating sample magnetometer requires the vibration head to move in simple harmonic motion. The force exerted on a simple harmonic motion object is proportional to the displacement and always points to the equilibrium position. The force exerted on the mover in the linear voice coil motor is the combined force of gravity and the Ampere force exerted on the current. In the present invention, the DC signal source provides the DC current in the voice coil winding via the current source to just compensate for the gravity of the mover. Then the AC current provided by the AC signal source to the voice coil winding is proportional to the vibration displacement of the mover, and the phase is opposite. The use of a first-order integrator can well perform the function of the difference amplifier. The AC signal source and the analog displacement signal have equal amplitudes and opposite phases, so that the difference amplifier (first-order integrator) can stably output a signal in phase with the AC signal source.

[0032] The vibration device of the invention has an adjustable amplitude (0.5-2 mm), an adjustable vibration frequency (10-80 Hz), and stable vibration frequency and amplitude of the sample.

[0033] To sum up, in the vibration device of the present invention, a cylindrical linear voice coil motor is used as the vibration source. The linear voice coil motor works in an AC / DC superposition state. A grating ruler is used for displacement measurement. The digital displacement signal collected by the grating ruler is converted into an analog displacement signal by the displacement signal source for analog feedback. The present invention adopts a closed-loop control combining digital and analog. The analog displacement signal is an analog signal converted in real time from the digital displacement signal. The analog closed-loop circuit only performs AC signal feedback, and the DC signal is independently used to offset the weight of the linear voice coil motor rotor, thereby making the vibration frequency and amplitude stable. At the same time, it has small mass, large load capacity, simple and reliable control circuit, and technical indicators reach the level of foreign commercial instruments, which can replace imports.

[0034] Based on the above-mentioned vibration device of a vibrating sample magnetometer, the present invention also provides a vibration method of a vibrating sample magnetometer.

[0035] like Figure 2 As shown, a vibration method of a vibrating sample magnetometer uses a linear voice coil motor as a vibration source of the vibrating sample magnetometer, and the vibration method includes the following steps:

[0036] Providing a corresponding DC signal to the linear voice coil motor according to the gravity exerted on the linear voice coil motor mover, and placing the linear voice coil motor mover in a central equilibrium position through the DC signal;

[0037] The corresponding AC signal is set according to the preset vibration frequency and amplitude signal; the digital displacement signal of the linear voice coil motor rotor vibration is obtained at the same time, and converted into an analog displacement signal in real time;

[0038] Amplifying the difference between the AC signal and the analog displacement signal to output a differential AC signal;

[0039] The differential AC signal is superimposed on the DC signal to drive the linear voice coil motor mover to vibrate up and down at the center position.

[0040] The beneficial effects of the present invention are as follows: the vibration method of the present invention uses the linear voice coil motor as the vibration source of the vibrating sample magnetometer, and applies a DC signal to the linear voice coil motor to offset the gravity exerted on the linear voice coil motor mover, so that the linear voice coil motor mover is located at a central equilibrium position; the analog displacement signal is an analog signal converted in real time from a digital displacement signal, the analog closed-loop circuit only performs AC signal feedback, and adopts a closed-loop control combining digital and analog, so that the vibration frequency and amplitude are stable, and at the same time, the vibration method has small mass, large load capacity, simple and reliable control circuit, and technical indicators reach the level of foreign commercial instruments, which can replace imports.

[0041] In this specific embodiment:

[0042] Preferably, the DC signal is a DC voltage signal; and the linear voice coil motor mover is placed in a central equilibrium position by using the DC signal, specifically including converting the DC signal from a DC voltage signal into a DC current signal, inputting the DC current signal into the linear voice coil motor, and driving the linear voice coil motor mover to be in a central equilibrium position.

[0043] Preferably, the AC signal is specifically an AC voltage signal; and the differential AC signal is superimposed on the DC signal to drive the linear voice coil motor mover to vibrate up and down at the center position, specifically including:

[0044] The differential AC signal is superimposed on the DC signal to obtain an AC-DC mixed voltage signal, the AC-DC mixed voltage signal is converted into an AC-DC mixed current signal, and the AC-DC mixed current signal is input into the linear voice coil motor to drive the linear voice coil motor rotor to vibrate up and down at the center position.

[0045] The vibration method of the present invention uses a linear voice coil motor as a vibration source of a vibrating sample magnetometer, and applies a DC signal to the linear voice coil motor to offset the gravity exerted on the linear voice coil motor mover, so that the linear voice coil motor mover is located at a central equilibrium position; the analog displacement signal is an analog signal converted in real time from a digital displacement signal, and the analog closed-loop circuit only performs AC signal feedback, and adopts a closed-loop control combining digital and analog, so that the vibration frequency and amplitude are stable, and at the same time, the method has small mass, large load capacity, simple and reliable control circuit, and technical indicators reach the level of foreign commercial instruments, which can replace imported ones.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A vibrating device for a vibrating sample magnetometer, characterized in that: It includes a linear voice coil motor, a grating ruler, a microcontroller, a displacement signal source, an AC signal source, a differential amplifier, a DC signal source, an adder and a current source; the linear voice coil motor is arranged in cooperation with the grating ruler, and the grating ruler is used to detect the displacement of the output shaft of the linear voice coil motor vibrating up and down; the signal output end of the grating ruler is electrically connected to the input end of the microcontroller; the input end of the displacement signal source is electrically connected to the microcontroller, the input end of the AC signal source is electrically connected to the microcontroller, and the output end of the AC signal source and the output end of the displacement signal source are both electrically connected to the input end of the differential amplifier; The input end of the DC signal source is electrically connected to the microcontroller, the output end of the DC signal source and the output end of the differential amplifier are both electrically connected to the input end of the adder, and the output end of the adder is electrically connected to the linear voice coil motor through the current source; The microcontroller controls the DC signal source to send out a DC signal, so that the linear voice coil motor rotor is in a central balance position; the microcontroller sets the AC signal source according to the given frequency and amplitude signals, and controls the AC signal source to provide a corresponding AC signal, the microcontroller receives the digital displacement signal of the grating ruler and converts it into an analog displacement signal in real time using the displacement signal source; the AC signal provided by the AC signal source and the analog displacement signal are amplified by a differential amplifier to output a differential AC signal, the differential AC signal is superimposed on the DC signal provided by the DC signal source, and the voltage is converted into current through a current source to drive the linear voice coil motor rotor to vibrate up and down at the center position; when the entire vibration system is working stably, the frequency and amplitude of the AC signal provided by the AC signal source are equal to those of the analog displacement signal.

2. The vibrating device of the vibrating sample magnetometer according to claim 1, characterized in that: It also includes a slide, the output shaft of the linear voice coil motor is connected to the slide and can vibrate up and down along the slide; the grating ruler is installed on the slide.

3. The vibrating device of the vibrating sample magnetometer according to claim 1 or 2, characterized in that: The difference amplifier is specifically a first-order integrator.

4. A vibration method for a vibrating sample magnetometer, characterized in that: The vibration device of the vibrating sample magnetometer according to any one of claims 1 to 3 is subjected to vibration control, and a linear voice coil motor is used as a vibration source of the vibrating sample magnetometer, and the vibration method comprises the following steps: Providing a corresponding DC signal to the linear voice coil motor according to the gravity exerted on the linear voice coil motor mover, and placing the linear voice coil motor mover in a central equilibrium position through the DC signal; The corresponding AC signal is set according to the preset vibration frequency and amplitude signal; the digital displacement signal of the linear voice coil motor rotor vibration is obtained at the same time, and converted into an analog displacement signal in real time; Amplifying the difference between the AC signal and the analog displacement signal to output a differential AC signal; The differential AC signal is superimposed on the DC signal to drive the linear voice coil motor mover to vibrate up and down at the center position.

5. The vibrating method of a vibrating sample magnetometer according to claim 4, characterized in that: The DC signal is specifically a DC voltage signal; the linear voice coil motor mover is placed in a central equilibrium position by using the DC signal, specifically including converting the DC signal from a DC voltage signal into a DC current signal, inputting the DC current signal into the linear voice coil motor, and driving the linear voice coil motor mover to be in a central equilibrium position.

6. The vibrating method of a vibrating sample magnetometer according to claim 5, characterized in that: The AC signal is specifically an AC voltage signal; the difference AC signal is superimposed on the DC signal to drive the linear voice coil motor mover to vibrate up and down at the center position, specifically including: The differential AC signal is superimposed on the DC signal to obtain an AC-DC mixed voltage signal, the AC-DC mixed voltage signal is converted into an AC-DC mixed current signal, and the AC-DC mixed current signal is input into the linear voice coil motor to drive the linear voice coil motor rotor to vibrate up and down at the center position.

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