阅读说明：本技术 一种重力售货柜的重力传感器标定方法 (Gravity sensor calibration method for gravity vending cabinet ) 是由 程晓飞 胡波 黄琪轩 于 2021-10-28 设计创作，主要内容包括：本发明提供一种重力售货柜的重力传感器标定方法,首先由满量程的称重重量提取需要标定的重量值,以及温度的满量程中的温度值,建立一个二维的数据结构；另外,重力柜不止一个称重传感器,因此对每一个称重传感器进行标定,因此在标定的二维平面上,再增加一个维度,形状三维的立体标定空间；在重力售货柜生产完成,准备出货时,进行整机的标定,形成一个标定数据表,存储在内存中,在重力售货柜运营时,调取该标定的参数表,就可以计算当前的重量。这样在称重的计算中,通过重力传感器与温度的二维表参数就可以计算出准确的重量,减少了测量电路及温度的影响。(The invention provides a gravity sensor calibration method of a gravity vending cabinet, which comprises the steps of firstly extracting a weight value to be calibrated and a temperature value in the full range of temperature from the full range of weighing weight, and establishing a two-dimensional data structure; in addition, the gravity cabinet is provided with more than one weighing sensor, so that each weighing sensor is calibrated, and a three-dimensional calibration space with one dimension and a three-dimensional shape is added on a calibrated two-dimensional plane; when the gravity selling cabinet is produced and ready for shipment, the complete machine is calibrated to form a calibration data table which is stored in the memory, and when the gravity selling cabinet is operated, the calibrated parameter table is called to calculate the current weight. Therefore, in the weighing calculation, the accurate weight can be calculated through the gravity sensor and the two-dimensional table parameters of the temperature, and the influence of a measuring circuit and the temperature is reduced.)

1. A gravity sensor calibration method for a gravity vending cabinet is characterized by comprising the following steps:

calibrating the gravity sensor at different temperatures, wherein the temperature range is larger than the temperature range in which the gravity sales counter is normally used;

the calibration procedure at one temperature point is as follows:

s1, zeroing: when the weighing tray is empty, marking the resistance value at the moment;

s2, acquiring the sensitivity coefficient of an elastic element of the gravity sensor: the method comprises the steps of putting standard weight weights with different weights on a weighing tray, marking resistance values when the standard weight weights are put in respectively, and determining the sensitivity of the gravity sensor according to the ratio of the difference between the zeroing resistance value of the gravity sensor and the resistance value of the standard weight weights to the weight of the calibrated standard weight weights.

2. The gravity sensor calibration method for gravity sales counter according to claim 1, wherein a three-dimensional calibration data structure is formed by different calibrated weight values, different temperature values and different gravity sensors, when the gravity sales counter is produced and ready to be shipped, the calibration of the entire gravity sales counter is performed, a calibration data table is formed according to the three-dimensional calibration data structure and stored in the memory of the gravity sales counter, and when the gravity sales counter is operated, the calibration data table is retrieved to calculate the current weight of the commodity.

3. The method for calibrating gravity sensors of gravity sales containers of claim 2, wherein the step of performing the zero calibration of the gravity sensors at different temperatures is as follows:

a1, enabling the temperature of the gravity vending cabinet to reach the highest point, and emptying the goods in all channels;

a2, opening a zero-returning instruction of the gravity vending cabinet, and entering a zero-returning action;

a3, starting the refrigeration function of the gravity vending cabinet, and gradually reducing the temperature in the gravity vending cabinet;

a4, automatically detecting the temperature change by the system, and recording the current zero-reset ADC sampling value when the temperature is changed from an integer to an integer;

a5, when the temperature is reduced to the lowest point from the highest point, the zeroing action of the whole cabinet is completed;

a6, and then saving all the zeroed parameters to flash.

4. The gravity sensor calibration method for gravity sales counter according to claim 2, wherein the calibration of the gravity sensor sensitivity at different temperatures is performed by the following steps:

b1, enabling the temperature of the gravity vending cabinet to reach the highest point, and respectively placing weights with standard weight on each goods way;

b2, starting a sensitivity calibration instruction of the gravity sales counter, and entering a sensitivity calibration action;

b3, starting the refrigeration function of the gravity vending cabinet, and gradually reducing the temperature in the gravity vending cabinet;

b4, the system automatically detects the temperature change, and when the temperature changes from an integer to an integer, the current ADC sampling value is recorded;

b5, when the temperature is reduced to the lowest point from the highest point, the sensitivity calibration action of each cargo channel to the corresponding standard weight is completed;

b6, calculating sensitivity parameters according to the ADC sampling value, and then storing all the sensitivity parameters into a flash;

b7, replacing the standard weight with different weight, and repeating the steps B1-B6.

5. The gravity sensor calibration method for gravity vending containers as claimed in claim 2 or 4, wherein during weighing, ADC samples are obtained which are not weights but weights, and therefore, the ADC samples are firstly used for calculating the approximate weight through any sensitivity coefficient in an ADC sample table, then the latest standard weight is searched in a calibration data table, and finally the current weight is calculated according to the calibration parameters of the standard weight.

6. The gravity sensor calibration method for gravity sales counter according to claim 2 or 4, wherein when calibrating standard weight weights of different weights, the weights cannot have the same weight; after calibration, sorting according to the calibrated weight from small to large; if the calibration has the same weight, the calibration means that the weight is recalibrated, and the calibration position of the previous same weight is filled with the weight calibrated later.

Technical Field

The invention belongs to the technical field of gravity sensors, and particularly relates to a gravity sensor calibration method for a gravity vending cabinet.

Background

The gravity sensor mainly comprises an elastic element, a resistance strain gauge, a measuring circuit and a transmission cable 4. When the elastic element is deformed by gravity, the resistance of the resistance strain gauge changes, and the current weight can be calculated according to the change value of the resistance in the measuring circuit. The deformation of the elastic element is in direct proportion to the magnitude of the external force, and the resistance of the resistance strain gauge is in proportion to the deformation of the elastic element, so that the weight can be calculated by the measuring circuit according to the change of the resistance value.

The existing electronic scales have return-to-zero operation, the return-to-zero adjustment is carried out before weighing, and the sensitivity of a weighing sensor uses a factory set coefficient. And when the sensor leaves the factory, the sensitivity of each sensor is calibrated, and the sensitivity coefficient is stored in the memory. However, the elastic element, the strain resistor and the measuring circuit all change due to the change of temperature, so a corresponding table of the return-to-zero and the sensitivity coefficient is also needed to be made at different temperatures. At present, the gravity sensor rarely performs temperature compensation, and a small part of high-precision weighing uses the temperature compensation, but a complete calibration system is not formed, so that the solution is to ensure that the weighing sensor is used in a constant-temperature environment as much as possible.

The current gravity sales counter adopts gravity sensor to realize weighing of product, and prior art's shortcoming lies in:

1. the weighing machine can be used at normal temperature, the temperature is guaranteed to be 6-30 degrees as far as possible, when the cabinet door is opened, accurate weighing cannot be achieved due to interaction of the internal temperature and the external temperature, and accurate weighing can be achieved only when the cabinet door is closed and the temperature is stable.

2. The precision is not high, and the weight of the single product is limited.

3. The settlement is slow, and the temperature of the cabinet needs to be kept stable.

Disclosure of Invention

The invention aims to solve the technical problems and provides a gravity sensor calibration method for a gravity vending cabinet.

In order to achieve the purpose, the invention adopts the following technical scheme:

a gravity sensor calibration method for a gravity vending cabinet comprises the following steps:

calibrating the gravity sensor at different temperatures, wherein the temperature range is larger than the temperature range in which the gravity sales counter is normally used;

the calibration procedure at one temperature point is as follows:

s1, zeroing: when the weighing tray is empty, marking the resistance value at the moment;

s2, acquiring the sensitivity coefficient of an elastic element of the gravity sensor: the method comprises the steps of putting standard weight weights with different weights on a weighing tray, marking resistance values when the standard weight weights are put in respectively, and determining the sensitivity of the gravity sensor according to the ratio of the difference between the zeroing resistance value of the gravity sensor and the resistance value of the standard weight weights to the weight of the calibrated standard weight weights.

As a preferred technical scheme, a three-dimensional calibration data structure is formed by different calibrated weight values, different temperature values and different gravity sensors, when the gravity sales counter finishes production and prepares for delivery, the calibration of the whole gravity sales counter is carried out, a calibration data table is formed according to the three-dimensional calibration data structure and stored in the internal memory of the gravity sales counter, and when the gravity sales counter operates, the calibration data table is called to calculate the current lane weight.

As a preferred technical scheme, the steps of carrying out the zero resetting calibration of the gravity sensor at different temperatures are as follows:

a1, enabling the temperature of the gravity vending cabinet to reach the highest point, and emptying the goods in all channels;

a2, opening a zero-returning instruction of the gravity vending cabinet, and entering a zero-returning action;

a3, starting the refrigeration function of the gravity vending cabinet, and gradually reducing the temperature in the gravity vending cabinet;

a4, automatically detecting the temperature change by the system, and recording the current zero-reset ADC sampling value when the temperature is changed from an integer to an integer;

a5, when the temperature is reduced to the lowest point from the highest point, the zeroing action of the whole cabinet is completed;

a6, and then saving all the zeroed parameters to flash.

As a preferred technical scheme, the steps of calibrating the sensitivity of the gravity sensor at different temperatures are as follows:

b1, enabling the temperature of the gravity vending cabinet to reach the highest point, and respectively placing weights with standard weight on each goods way;

b2, starting a sensitivity calibration instruction of the gravity sales counter, and entering a sensitivity calibration action;

b3, starting the refrigeration function of the gravity vending cabinet, and gradually reducing the temperature in the gravity vending cabinet;

b4, the system automatically detects the temperature change, and when the temperature changes from an integer to an integer, the current ADC sampling value is recorded;

b5, when the temperature is reduced to the lowest point from the highest point, the sensitivity calibration action of each cargo channel to the corresponding standard weight is completed;

b6, calculating sensitivity parameters according to the ADC sampling value, and then storing all the sensitivity parameters into a flash;

b7, replacing the standard weight with different weight, and repeating the steps B1-B6.

As a preferred technical solution, during weighing, ADC sampled values that are not weights but weights are obtained, so that an approximate weight is calculated by using any sensitivity coefficient in an ADC sampled table for the ADC sampled values, then a latest standard weight is searched in a calibrated calibration data table, and finally a current weight is calculated according to a calibration parameter of the standard weight.

As a preferred technical scheme, when calibrating standard weights with different weights, the weights cannot have the same weight; after calibration, sorting according to the calibrated weight from small to large; if the calibration has the same weight, the calibration means that the weight is recalibrated, and the calibration position of the previous same weight is filled with the weight calibrated later.

After the technical scheme is adopted, the invention has the following advantages:

the invention relates to a gravity sensor calibration method of a gravity sales counter, which comprises the steps of firstly extracting a weight value to be calibrated and a temperature value in a full range of temperature from a full range of weighing weight, and establishing a two-dimensional data structure; in addition, the gravity cabinet is provided with more than one weighing sensor, so that each weighing sensor is calibrated, and a three-dimensional calibration space with one dimension and a three-dimensional shape is added on a calibrated two-dimensional plane; when the gravity selling cabinet is produced and ready for shipment, the complete machine is calibrated to form a calibration data table which is stored in the memory, and when the gravity selling cabinet is operated, the calibrated parameter table is called to calculate the current weight. Therefore, in the weighing calculation, the accurate weight can be calculated through the gravity sensor and the two-dimensional table parameters of the temperature, and the influence of a measuring circuit and the temperature is reduced.

Drawings

FIG. 1 is a table of error comparisons of standard weight and weighed weight;

FIG. 2 is a calibrated data structure and algorithm;

FIG. 3 is a graph of zeroing calibration and sensitivity calibration data for a gravity sensor at a certain temperature.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and specific examples.

A gravity sensor calibration method for a gravity vending cabinet comprises the following steps:

calibrating the gravity sensor at different temperatures, wherein the temperature range is larger than the temperature range in which the gravity sales counter is normally used;

the calibration procedure at one temperature point is as follows:

s1, zeroing: when the weighing tray is empty, marking the resistance value at the moment;

s2, acquiring the sensitivity coefficient of an elastic element of the gravity sensor: the method comprises the steps of putting standard weight weights with different weights on a weighing tray, marking resistance values when the standard weight weights are put in respectively, and determining the sensitivity of the gravity sensor according to the ratio of the difference between the zeroing resistance value of the gravity sensor and the resistance value of the standard weight weights to the weight of the calibrated standard weight weights.

Because of the impedance difference of the components of the circuit, the self weight of the elastic element of the gravity sensor and the weight of the weighed tray, the gravity sensor needs to be calibrated before use. The calibration was divided into 2 parts: one is zero, when the weighing tray is empty, the resistance value at the moment is marked; the second is the sensitivity coefficient of the elastic element, when the weighing tray is put into the standard weight, the resistance value at that time is marked. The sensitivity of the load cell is determined by the weight ratio of the difference between the 2 resistance values and the standard weight.

The method comprises the steps that a three-dimensional calibration data structure is formed by calibrated different weight values, different temperature values and different gravity sensors, when the gravity sales counter is produced and ready to be delivered, the whole gravity sales counter is calibrated, a calibration data table is formed according to the three-dimensional calibration data structure and stored in an internal memory of the gravity sales counter, and when the gravity sales counter is operated, the calibration data table is called to calculate the current lane weight.

Because the impedance of the measuring circuit can affect the whole measured resistance value, the voltage of the measuring circuit can also have the influence of noise, and the influence of the resistance value is not proportional to the gravity, when calibrating the sensitivity coefficient of the weighing sensor, the coefficients of different standard weights need to be calibrated, and a coefficient table is made so as to calculate the weight according to the closest sensitivity coefficient when weighing. In addition, the elastic element, the strain resistor and the measuring circuit all change due to the change of temperature, so that calibration data tables of return-to-zero and sensitivity coefficients are needed to be made at different temperatures.

The steps of zero resetting and calibrating the gravity sensor at different temperatures are as follows:

a1, enabling the temperature of the gravity vending cabinet to reach the highest point, and emptying the goods in all channels;

a2, opening a zero-returning instruction of the gravity vending cabinet, and entering a zero-returning action;

a3, starting the refrigeration function of the gravity vending cabinet, and gradually reducing the temperature in the gravity vending cabinet;

a4, automatically detecting the temperature change by the system, and recording the current zero-reset ADC sampling value when the temperature is changed from an integer to an integer;

a5, when the temperature is reduced to the lowest point from the highest point, the zeroing action of the whole cabinet is completed;

a6, and then saving all the zeroed parameters to flash.

The steps of calibrating the sensitivity of the gravity sensor at different temperatures are as follows:

b1, enabling the temperature of the gravity vending cabinet to reach the highest point, and respectively placing weights with standard weight on each goods way;

b2, starting a sensitivity calibration instruction of the gravity sales counter, and entering a sensitivity calibration action;

b3, starting the refrigeration function of the gravity vending cabinet, and gradually reducing the temperature in the gravity vending cabinet;

b4, the system automatically detects the temperature change, and when the temperature changes from an integer to an integer, the current ADC sampling value is recorded;

b5, when the temperature is reduced to the lowest point from the highest point, the sensitivity calibration action of each cargo channel to the corresponding standard weight is completed;

b6, calculating sensitivity parameters according to the ADC sampling value, and then storing all the sensitivity parameters into a flash;

b7, replacing the standard weight with different weight, and repeating the steps B1-B6.

During weighing, the ADC sampling value which is not weight but weight is obtained, therefore, the ADC sampling value is firstly used for calculating the approximate weight through any sensitivity coefficient in an ADC sampling table, then the latest standard weight is searched in a calibrated calibration data table, and finally the current weight is calculated according to the calibration parameter of the standard weight.

When calibrating standard weights with different weights, the weights cannot have the same weight; after calibration, sorting according to the calibrated weight from small to large; if the calibration has the same weight, the calibration means that the weight is recalibrated, and the calibration position of the previous same weight is filled with the weight calibrated later.

The following is an example of calibration data of the gravity sensor calibration method of the gravity vending cabinet of the invention:

as can be seen from fig. 1, the sensitivity of the gravity sensor is fixed, and the weighing is basically proportional to the standard weight, but due to the influence of the measuring circuit, the sensitivity is deviated under different gravity forces, so that corresponding sensitivity calibration needs to be performed under different gravity forces.

When calibration of different standard weights is carried out, the calibration needs to be averaged to the full scale as much as possible, and the more the calibrated weight is, the more the weighing is accurate, but the more the calibrated quantity is, the more the data needs to be stored, the more the storage space is needed, the resource requirement is high, and the longer the calibration time is, so that the calibration needs to be converted into a reasonable quantity.

In the same calibration, calibration needs to be performed at different temperatures, and certainly, in the full range of the temperature, the smaller the calibrated temperature difference is, the higher the calculation accuracy is, but the smaller the calibrated temperature difference is, the stored data of the calibration can be multiplied, so that a reasonable quantification needs to be performed on the calibrated temperature difference. In this example, the temperature is accurate to centigrade.

As shown in fig. 2, is a calibrated data structure, the calibrated temperature is from-30 deg. -40 deg., and the calibrated temperature interval is 1 deg.. The standard weight of demarcation is 9 weights, and 10 KG's full scale is markd 1KG, 2KG, 3KG, 4KG, 5KG, 6KG, 7KG, 8KG, 9KG, removes the weight of balance, and the full scale of general reality is exactly 9.5 KG.

The calibration forms a two-dimensional weighing full-coverage calibration net, and the accurate weight can be calculated by searching the nearest grid parameters in the calibrated two-dimensional net according to the weighing measurement value during calculation.

As shown in fig. 3, the calibration data of a sensor at a certain temperature is normalized to 16603762, the sensitivity is 183, but the sensitivity is different under different weights, because of the influence of the measuring circuit, so that calibration values of a plurality of standard weights are needed. Wherein, the sensitivity K = (ADcur-ADzero)/Wcur, that is, the measured current resistance value minus the resistance value at zero, divided by the calibrated current weight.

Calibration at different temperatures results in a two-dimensional planar grid as shown in the following table.

Calibrating temperature	Zero ADC value	Sensitivity K1		Sensitivity Kn
					40°	A40	K1-40		Kn-40
39°	A39	K1-39		Kn-39
					38°	A38	K1-38		Kn-38
…	…	…		…
					…	…	…		…
1°	A1	K1-1		Kn-1
					0°	A0	K1-0		Kn-0
-1°
					…	…	…		…
…	…	…		…
					-29°
-30°

Other embodiments of the present invention than the preferred embodiments described above will be apparent to those skilled in the art from the present invention, and various changes and modifications can be made therein without departing from the spirit of the present invention as defined in the appended claims.