阅读说明：本技术 一种磁悬浮称重系统及其控制方法 (Magnetic suspension weighing system and control method thereof ) 是由 鲍丙好 宋圆圆 于 2021-08-16 设计创作，主要内容包括：本发明提供一种磁悬浮称重系统及其控制方法,包括箱体；所述箱体的顶部安装有称重机构,所述称重机构包括磁悬浮组件、悬浮物和盛物盘,所述盛物盘连接在悬浮物下方；所述磁悬浮组件包括光电位移传感器、线路板、电磁线圈和显示屏；所述悬浮物位于电磁线圈的正下方；所述光电位移传感器用于测量悬浮物与电磁线圈之间的距离；所述线路板分别与光电位移传感器和电磁线圈连接。本发明能够根据盛物盘中所加不同质量的物体,自动调节电磁线圈上的电流,变化的电流与物体的质量精确对应,从而达到间接测重的目的；该称重系统利用磁力平衡物体重力,消除了传统电子秤秤体的机械摩擦,提高了测量精度。(The invention provides a magnetic suspension weighing system and a control method thereof, comprising a box body; the top of the box body is provided with a weighing mechanism, the weighing mechanism comprises a magnetic suspension assembly, suspended matters and a containing disc, and the containing disc is connected below the suspended matters; the magnetic suspension assembly comprises a photoelectric displacement sensor, a circuit board, an electromagnetic coil and a display screen; the suspension is positioned right below the electromagnetic coil; the photoelectric displacement sensor is used for measuring the distance between the suspended matter and the electromagnetic coil; the circuit board is respectively connected with the photoelectric displacement sensor and the electromagnetic coil. The invention can automatically adjust the current on the electromagnetic coil according to objects with different masses added in the object containing disc, and the changed current accurately corresponds to the mass of the object, thereby achieving the aim of indirect weight measurement; the weighing system utilizes magnetic force to balance the gravity of an object, eliminates the mechanical friction of the balance body of the traditional electronic scale and improves the measurement precision.)

1. A magnetic suspension weighing system is characterized by comprising a box body (1); the top (2) of the box body (1) is provided with a weighing mechanism, the weighing mechanism comprises a magnetic suspension assembly, suspended matters (8) and a containing disc (9), and the containing disc (9) is connected below the suspended matters (8); the magnetic suspension assembly comprises a photoelectric displacement sensor, a circuit board (10), an electromagnetic coil (5) and a display screen (11); the suspension (8) is positioned right below the electromagnetic coil (5); the photoelectric displacement sensor is used for measuring the distance between the suspended matter (8) and the electromagnetic coil (5); the circuit board (10) is respectively connected with the photoelectric displacement sensor and the electromagnetic coil (5).

2. The magnetic suspension weighing system according to claim 1, characterized in that the photoelectric displacement sensor comprises a parallel light source (6) and a photosensitive element, the parallel light source (6) and the photosensitive element are respectively arranged at the left and right ends of the electromagnetic coil (5).

3. The magnetic suspension weighing system of claim 2, wherein the light sensing element is a silicon photocell.

4. Magnetic suspension weighing system according to claim 3, characterised in that said silicon photocell comprises a first silicon photocell (7) and a second silicon photocell (14); the first silicon photocell (7) and the second silicon photocell (14) are arranged up and down to form a differential photoelectric displacement sensor together with the parallel light source (6).

5. The magnetic suspension weighing system according to claim 1, characterized in that the circuit board (10) comprises a power supply module, a photoelectric displacement sensor output signal processing module, a PID control circuit module, a driving circuit module, an A/D conversion module, a Micro Control Unit (MCU), an overweight alarm module and a display module;

the power supply module is used for providing power supply for the system;

the photoelectric displacement sensor output signal processing module is used for filtering and impurity removing the detected position signal of the suspended matter (8);

the PID control circuit module is used for processing the signal difference detected by the photoelectric displacement sensor and controlling the suspended matters (8) to be maintained at the same balance point as the input of the driving circuit module;

the driving circuit module is used for adjusting the current of the electromagnetic coil (5);

the A/D conversion module is used for converting a voltage signal on the electromagnetic coil (5) into a digital signal;

the micro control unit MCU is used for comparing the digital signal output by the A/D conversion module with a preset value and controlling the overweight alarm module to alarm when the digital signal exceeds the preset value;

the overweight alarm module is used for giving an alarm when the weight of an object in the object containing disc (9) exceeds an alarm preset weight value;

the display module is used for displaying the object quality data.

6. Magnetic suspension weighing system according to claim 1, characterised in that the box (1) is covered on its periphery with black insulating tape.

7. Magnetic suspension weighing system according to claim 1, characterised in that the voltage v of the electromagnetic coil (5) and the mass m of the object to be measured satisfy the following relation:

and m is av + b, and a proportional linear relation is presented, wherein a is the slope of a fitted straight line, and b is an intercept.

8. A method of controlling a magnetic levitation weighing system as recited in any one of claims 1-7, characterised by the steps of:

the photoelectric displacement sensor measures the distance between the suspended matter (8) and the electromagnetic coil (5), namely the position of the suspended matter (8), when a heavy object is loaded in the object containing disc (9), the output of the photoelectric displacement sensor changes, the current on the electromagnetic coil (5) is adjusted through the circuit board (10), so that the attraction force borne by the suspended matter (8) is increased, and the suspended matter (8) returns to the original position again; the voltage signal of output on solenoid (5) is sent into circuit board (10) and is handled, finally shows the quality of testee through display module, and circuit board (10) send out the police dispatch newspaper when the weight value that detects surpasss preset weight value.

Technical Field

The invention belongs to the field of magnetic suspension, and particularly relates to a magnetic suspension weighing system and a control method thereof.

Background

The error of the traditional electronic scale mainly comes from the following aspects: a four corner offset load error, a weighing error, an identification force error and a repeatability error. The bias loading error of the four corners is derived from the sensitivity of the weighing sensor; the linear change, zero drift and the leaning of the weighing platform of the sensor are direct reasons for weighing errors; friction and stress in mechanical connections are the main sources of discriminant force errors; the repeatability error is caused by the influence of some relatively fixed factors, such as temperature, humidity, wind power, gravity field and other environmental conditions during weighing measurement. Through the analysis, the generation of the four-corner unbalance loading error, the weighing error and the identification force error is related to the design structure of the weighing system, and the influence of the friction force on the precision of the symmetry quantity can not be avoided in the weighing process.

Disclosure of Invention

Aiming at the technical problem, the invention provides a magnetic suspension weighing system and a control method thereof, which can automatically adjust the current on an electromagnetic coil according to objects with different masses added in a containing disc, and the changed current accurately corresponds to the mass of the object, thereby achieving the aim of indirect weight measurement; the weighing system utilizes magnetic force to balance the gravity of an object, eliminates the mechanical friction of the balance body of the traditional electronic scale and improves the measurement precision.

The technical scheme of the invention is as follows: a magnetic suspension weighing system comprises a box body; the top of the box body is provided with a weighing mechanism, the weighing mechanism comprises a magnetic suspension assembly, suspended matters and a containing disc, and the containing disc is connected below the suspended matters; the magnetic suspension assembly comprises a photoelectric displacement sensor, a circuit board, an electromagnetic coil and a display screen; the suspension is positioned right below the electromagnetic coil; the photoelectric displacement sensor is used for measuring the distance between the suspended matter and the electromagnetic coil; the circuit board is respectively connected with the photoelectric displacement sensor and the electromagnetic coil.

In the above scheme, the photoelectric displacement sensor includes a parallel light source and a photosensitive element, and the parallel light source and the photosensitive element are respectively disposed at the left end and the right end of the electromagnetic coil.

Further, the photosensitive element is a silicon photocell.

Further, the silicon photocell comprises a first silicon photocell and a second silicon photocell; the first silicon photocell and the second silicon photocell are arranged up and down to form a differential photoelectric displacement sensor with the parallel light source.

In the scheme, the circuit board comprises a power supply module, a photoelectric displacement sensor output signal processing module, a PID control circuit module, a driving circuit module, an A/D conversion module, a micro control unit MCU, an overweight alarm module and a display module;

the power supply module is used for providing power supply for the system;

the photoelectric displacement sensor output signal processing module is used for filtering and impurity removing the detected position signals of the suspended matters;

the PID control circuit module is used for processing the signal difference detected by the photoelectric displacement sensor and controlling suspended matters to be maintained at the same balance point as the input of the driving circuit module;

the driving circuit module is used for adjusting the current of the electromagnetic coil;

the A/D conversion module is used for converting a voltage signal on the electromagnetic coil into a digital signal;

the micro control unit MCU is used for comparing the digital signal output by the A/D conversion module with a preset value and controlling the overweight alarm module to alarm when the digital signal exceeds the preset value;

the overweight alarm module is used for giving an alarm when the weight of the object in the object containing disc exceeds an alarm preset weight value;

the display module is used for displaying the object quality data.

In the scheme, the periphery of the box body is covered by the black insulating adhesive tape.

In the above scheme, the voltage v of the electromagnetic coil and the mass m of the measured object satisfy the following relationship:

and m is av + b, and a proportional linear relation is presented, wherein a is the slope of a fitted straight line, and b is an intercept.

A method of controlling the magnetic levitation weighing system, comprising the steps of:

the photoelectric displacement sensor measures the distance between the suspended matter and the electromagnetic coil, namely the position of the suspended matter, when a heavy object is loaded in the object containing disc, the output of the photoelectric displacement sensor changes, the current on the electromagnetic coil is adjusted through the circuit board, so that the attraction force borne by the suspended matter is increased, and the suspended matter returns to the original position again; the voltage signal of output on the electromagnetic coil sends into the circuit board and handles, finally shows the quality of testee through display module, and the circuit board sends out the police dispatch newspaper when the weight value that detects surpasss preset weight value.

Compared with the prior art, the invention has the beneficial effects that: the invention provides a magnetic suspension weighing system and a control method thereof.A differential photoelectric displacement sensor is used for detecting the position of a spherical suspended matter; the position of the spherical suspended matter is controlled more stably through the parallel PID control circuit module. The current of the electromagnetic coil is automatically adjusted through the driving circuit module. The structure design is simple and reasonable, the mechanical structure of the scale body of the traditional electronic scale is changed, the influence of friction force on the precision of the weighing is eliminated, and the weighing error is small.

Drawings

FIG. 1 is a schematic diagram of an internal structure of a magnetic suspension weighing system according to the present invention;

FIG. 2 is a top view of a magnetic levitation weighing system in accordance with the present invention;

FIG. 3 is a schematic view of a first fixed frame of a magnetic levitation weighing system according to the present invention;

fig. 4 is a schematic view of a second fixed frame of a magnetic suspension weighing system according to the present invention.

Fig. 5 is a circuit for designing a differential photoelectric displacement sensor of a magnetic suspension weighing system according to the present invention.

Fig. 6 is a block diagram of a magnetic suspension weighing system according to the present invention.

In the figure: 1. a box body; 2. the top of the box body; 3. a first fixed frame; 4. a second fixed frame; 5. an electromagnetic coil; 6. a collimated light source; 7. a first silicon photocell; 8. suspended matter; 9. a holding tray; 10. a circuit board; 11. a display screen; 12. a fixed block; 13. screws; 14. and a second silicon photocell.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Fig. 1 and 2 show a preferred embodiment of the magnetic suspension weighing system, which comprises a box 1; the top 2 of the box body 1 is provided with a weighing mechanism, the weighing mechanism comprises a magnetic suspension assembly, suspended matters 8 and a containing disc 9, and the containing disc 9 is connected below the suspended matters 8; the magnetic suspension assembly comprises a photoelectric displacement sensor, a circuit board 10, an electromagnetic coil 5 and a display screen 11; the suspension 8 is positioned right below the electromagnetic coil 5; the photoelectric displacement sensor is used for measuring the distance between the suspended matter 8 and the electromagnetic coil 5; the circuit board 10 is respectively connected with the photoelectric displacement sensor and the electromagnetic coil 5.

The electromagnetic coil 5 contains an iron core and is fixed on the top 2 of the box body through a fixed block 12 and a screw 13; the photosensitive element is installed by using the first fixed frame 3, the parallel light source 6 is installed by using the second fixed frame 4, and the position is adjusted, so that the parallel light source 6 and the photosensitive element are positioned on the same axis; a spherical suspension 8 and a containing plate 9 connected below the suspension are arranged right below the electromagnetic coil 5 and on the same vertical axis.

Preferably, the material of the box body 1, the first fixed frame 3, the second fixed frame 4 and the fixed block 12 are all acrylic plates.

Preferably, the periphery of the box body 1 is covered by a black insulating tape so as to reduce the influence of ambient light on the parallel light source 6 and improve the accuracy of the photoelectric displacement sensor in detecting the position of the spherical suspended matter 8.

As shown in fig. 3 and 4, according to the present embodiment, preferably, the photoelectric displacement sensor includes a collimated light source 6 and a photosensitive element, and the collimated light source 6 and the photosensitive element are respectively disposed at the left and right ends of the electromagnetic coil 5, and are adjustable in position. Preferably, the photosensitive element is a silicon photocell. The silicon photocells comprise a first silicon photocell 7 and a second silicon photocell 14; the first silicon photocell 7 and the second silicon photocell 14 are arranged up and down to form a differential photoelectric displacement sensor with the parallel light source 6.

The silicon photocell mainly utilizes the photovoltaic effect to directly convert light energy into electric energy. Through the analysis of the illumination characteristic curve, the short-circuit current of the silicon photocell is in linear relation with the luminous flux and thus the light receiving area. Because the spherical suspended substance 8 is arranged between the parallel light source and the silicon photocell, the spherical suspended substance 8 can prevent partial light from passing through, the short-circuit current output by the silicon photocell at the moment is not the maximum value, but a value which is in linear relation with the position of the suspended substance 8, namely, the change of the short-circuit current reflects the change of the position 8 of the suspended substance, thereby achieving the purpose of measuring the displacement.

As shown in FIG. 5, in order to accurately detect the position of the spherical suspended matter 8, a differential photoelectric displacement sensor is designed by using the parallel light source 6 and two silicon photocells, because the short-circuit current of the silicon photocell is in linear relation with the position of the suspended matter 8, and the voltage can be more conveniently processed, a current-voltage conversion circuit is firstly designed, and the used element device is usedThe device mainly comprises an operational amplifier D₁、D₂A resistor R connected in parallel to the inverting input terminal and the output terminal of the operational amplifier₂、R₅Resistance value of 47K, capacitance C₁、C₂The capacitance values are 473, and a resistor R is connected to the non-inverting input terminal of the operational amplifier₃、R₄The resistance value is 1K, the circuit converts the short-circuit current of the silicon photocell into corresponding voltage quantity, the voltage and the current are in linear relation, and therefore the voltage and the current are in linear relation with the position of the spherical suspended matter 8 and are connected in parallel with the feedback resistor R₂、R₅Small capacitance c at both ends₁、c₂The effect of suppressing high-frequency noise can be achieved. After the two silicon photocells are respectively treated, the output of the two silicon photocells is subtracted by a subtraction circuit, and the circuit of the subtraction circuit is mainly provided with an operational amplifier D₃A resistor R connected in parallel to the inverting input terminal and the output terminal of the operational amplifier₉The resistance value is 100K, and a resistor R is connected to the non-inverting input end₈The resistance value is also 100K, and the signal difference of the two silicon photocells obtained by the circuit is still in linear relation with the position of the spherical suspended matter 8. When the spherical suspended matter 8 is in a balanced state, the difference value of the output signals of the two silicon photocells is fixed, when the position of the spherical suspended matter 8 moves up or down, the luminous flux changes, the difference value of the output signals of the two silicon photocells 7 and 14 changes along with the change of the luminous flux, the magnitude of the current on the electromagnetic coil 5 is adjusted through the circuit board, the magnitude of the electromagnetic force applied to the spherical suspended matter 8 is changed, and the spherical suspended matter 8 returns to the original balanced position again. Compared with the displacement detection only by using a single-side photocell, the differential structure can inhibit common-mode noise and obtain a better signal-to-noise ratio on one hand, and can improve the linearity near the detection zero point, weaken the nonlinear link of the system and enhance the stability margin of suspension control on the other hand.

As shown in fig. 6, according to this embodiment, preferably, the circuit board 10 includes a power module, a photoelectric displacement sensor output signal processing module, a PID control circuit module, a driving circuit module, an a/D conversion module, a micro control unit MCU, an overweight alarm module and a display module; the power supply module is used for providing power supply for the system; the photoelectric displacement sensor output signal processing module is used for filtering and impurity removing the detected position signal of the suspended matter 8 and mainly comprises a current-voltage conversion circuit, a voltage follower, a filter and the like; the PID control circuit module is used for processing the signal difference between a first silicon photocell and a second silicon photocell in the photoelectric displacement sensor, and is used as the input of the driving circuit module to control the suspended matters 8 to be maintained at the same balance point, and comprises three basic circuits of proportion, integral and differential; the driving circuit module is used for adjusting the current of the electromagnetic coil 5 and is realized by utilizing the characteristic of voltage control current of a high-power field effect transistor; the A/D conversion module is used for converting a voltage signal on the electromagnetic coil 5 into a digital signal; the micro control unit MCU is used for comparing the digital signal output by the A/D conversion module with a preset value and controlling the overweight alarm module to alarm when the digital signal exceeds the preset value; the overweight alarm module is used for giving an alarm when the weight of the object in the object containing disc 9 exceeds an alarm preset weight value; the display module is used for displaying the object quality data.

According to this embodiment, the suspension 8 is preferably spherical and is subjected to electromagnetic forces of:i is the current on the electromagnetic coil 5, x is the distance between the spherical suspension 8 and the bottom end of the electromagnetic coil 5, k is a constant coefficient,wherein u is_oIs the air permeability, N is the number of turns of the electromagnetic coil 5, A is the cross-sectional area of the magnetic flux of the entire air gap below the electromagnetic coil 5, in order to make the magnetic flux flow through the magnetic conduction area of the section of the small ball, the nonlinear inverse proportion relation between F and x can be seen, which shows that the magnetic suspension is actually in an unstable equilibrium state as long as the magnetic suspension is subjected toThe small disturbance will cause the spherical suspended matter 8 to drop or be absorbed by the electromagnet, so the closed loop feedback loop must be added to realize the closed loop control, and the system can be stabilized.

According to this embodiment, it is preferable that the suspension 8 is in a stable suspension state, and the gravity is equal to the magnetic suspension force, i.e. the suspension is subjected toWherein m is₁The mass of the suspended matter 8 and the containing plate 9, and g is the gravity acceleration; when a heavy object is loaded in the object containing tray 9, the distance x is kept unchanged by adjusting the current i on the electromagnetic coil 5 through the circuit board 10, and the current i corresponds to the mass of the object to be weighed accurately, so that the purpose of weighing is achieved.

According to the present embodiment, preferably, the model of the correspondence relationship between the voltage v of the electromagnetic coil 5 and the mass m of the measured object is m ═ av + b, and a is a proportional linear relationship, where a is the slope of the fitted straight line and b is the intercept.

A method of controlling the magnetic levitation weighing system, comprising the steps of:

the photoelectric displacement sensor measures the distance between the suspended matter 8 and the electromagnetic coil 5, namely the position of the suspended matter 8, when a heavy object is loaded in the object containing disc 9, the output of the photoelectric displacement sensor changes, the current on the electromagnetic coil 5 is adjusted through the circuit board 10, so that the attraction force on the suspended matter 8 is increased, and the suspended matter 8 returns to the original position again; the voltage signal of output on the solenoid 5 sends into circuit board 10 and handles, finally shows the quality of testee through display module, and circuit board 10 sends out the police dispatch newspaper when the weight value that detects surpasss preset weight value.

Specifically, the photoelectric displacement sensor detects the position of the spherical suspended matter 8 in real time, after a heavy object is loaded in the object containing disc 9, the original balance state is broken, the output of the photoelectric displacement sensor changes, and the current on the electromagnetic coil 5 is adjusted through a closed loop feedback loop formed by a PID control circuit module, a driving circuit module and the like, so that the attraction force on the spherical suspended matter 8 is increased, and the spherical suspended matter 8 returns to the original balance position again. The current signal on the electromagnetic coil 5 is taken out by using the sampling resistor, the output voltage signal is sent to the MCU for processing after A/D conversion, and finally the quality of the object is displayed through the display screen. And recording the mass of the object weighed each time and the corresponding voltage signal, and fitting a corresponding relation model of the voltage and the mass of the object by processing a large amount of experimental data and adopting other modes such as linear regression and the like. And when the weight value detected by the MCU exceeds the alarm preset weight value, the overweight alarm module gives an alarm.

The position of a spherical suspended matter 8 is detected by a differential photoelectric displacement sensor; the position of the spherical suspended matter is controlled more stably through the parallel PID control circuit module. The current of the electromagnetic coil is automatically adjusted through the driving circuit module. The structure design is simple and reasonable, the mechanical structure of the scale body of the traditional electronic scale is changed, the influence of friction force on the precision of the weighing is eliminated, and the weighing error is small.

It should be understood that although the present description has been described in terms of various embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and those skilled in the art will recognize that the embodiments described herein may be combined as suitable to form other embodiments, as will be appreciated by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.