EP-4735828-A1 - CALIBRATION METHOD AND APPARATUS FOR ELECTRONIC BUBBLE LEVEL, AND COMPUTER-READABLE MEDIUM

EP4735828A1EP 4735828 A1EP4735828 A1EP 4735828A1EP-4735828-A1

Abstract

The present application provides a calibration method and apparatus for an electronic bubble level, and a computer-readable medium. The calibration method includes: controlling a tilt state of the electronic bubble level, so that the electronic bubble level is in a first state, and in this state, a first target position is higher than a second target position, and a bubble comes into contact with a side wall; obtaining a first photoelectric signal of the electronic bubble level, where the first photoelectric signal corresponds to a first bubble position; controlling the tilt state of the electronic bubble level, so that the electronic bubble level is in a second state, and in this state, the second target position is higher than the first target position, and the bubble comes into contact with the side wall; obtaining a second photoelectric signal of the electronic bubble level, where the second photoelectric signal corresponds to a second bubble position; obtaining a third photoelectric signal existing when the electronic bubble level is in a third state, where the third photoelectric signal corresponds to a third bubble position; and calibrating a bubble position calculation model of the electronic bubble level based on the first photoelectric signal, the second photoelectric signal, and the third photoelectric signal.

Inventors

WANG, CHANGLIN
XU, Jiajie
CHEN, XINGHONG
TIAN, Cuicui
ZHU, Fengjun

Assignees

Mettler-Toledo Instruments (Shanghai) Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20240301

Claims (19)

A calibration method for an electronic bubble level, wherein the electronic bubble level has a housing, wherein a liquid and a bubble are arranged inside a side wall of the housing, the side wall of the housing has at least two target positions, and the at least two target positions comprise a first target position and a second target position, characterized in that the method comprises: controlling a tilt state of the electronic bubble level, so that the electronic bubble level is in a first state, and in this state, the first target position is higher than the second target position, and the bubble comes into contact with the side wall; obtaining a first photoelectric signal of the electronic bubble level in the first state, wherein the first photoelectric signal corresponds to a first bubble position of the bubble; controlling the tilt state of the electronic bubble level, so that the electronic bubble level is in a second state, and in this state, the second target position is higher than the first target position, and the bubble comes into contact with the side wall; obtaining a second photoelectric signal of the electronic bubble level in the second state, wherein the second photoelectric signal corresponds to a second bubble position of the bubble; obtaining a third photoelectric signal existing when the electronic bubble level is in a third state, wherein the third photoelectric signal corresponds to a third bubble position of the bubble; and calibrating a bubble position calculation model of the electronic bubble level based on the first photoelectric signal, the second photoelectric signal, and the third photoelectric signal.
The calibration method according to claim 1, characterized in that the step of calibrating a bubble position calculation model of the electronic bubble level based on the first photoelectric signal, the second photoelectric signal, and the third photoelectric signal comprises: establishing a first empirical formula for the third bubble position and a difference between the third photoelectric signal and the first photoelectric signal, wherein the first empirical formula has a first parameter; establishing a second empirical formula for the third bubble position and a difference between the third photoelectric signal and the second photoelectric signal, wherein the second empirical formula has a second parameter; and obtaining the first parameter and the second parameter through numerical calculation.
The calibration method according to claim 2, characterized in that the electronic bubble level has m light-emitting apparatuses and n receiving apparatuses, wherein both m and n are positive integers greater than or equal to 2, the first parameter comprises a first x parameter and a first y parameter, and the first empirical formula is represented by using the following formula: wherein i=1: m indicates a first to an m th light-emitting apparatuses in the electronic bubble level; j=1: n indicates a first to an n th receiving apparatuses in the electronic bubble level; Uij indicates a third photoelectric signal of an i th light-emitting apparatus that is received by a j th receiving apparatus when the bubble is at the third bubble position; Uaij indicates a first photoelectric signal of the i th light-emitting apparatus that is received by the j th receiving apparatus when the bubble is at the first bubble position; x3 a represents an x coordinate that is of the third bubble position in a Cartesian coordinate system and that is obtained through calculation by using Uaij as a reference, and y3 a represents a y coordinate that is of the third bubble position in the Cartesian coordinate system and that is obtained through calculation by using Uaij as a reference; Kxaij represents the first x parameter; and Kyaij represents the first y parameter.
The calibration method according to claim 3, characterized in that the electronic bubble level has the m light-emitting apparatuses and the n receiving apparatuses, wherein both m and n are positive integers greater than or equal to 2, the second parameter comprises a second x parameter and a second y parameter, and the second empirical formula is represented by using the following formula: wherein i=1: m indicates the first to the m th light-emitting apparatuses in the electronic bubble level; j=1: n indicates the first to the n th receiving apparatuses in the electronic bubble level; Uij indicates the third photoelectric signal of the i th light-emitting apparatus that is received by the j th receiving apparatus when the bubble is at the third bubble position; Ubij indicates a second photoelectric signal of the i th light-emitting apparatus that is received by the j th receiving apparatus when the bubble is at the second bubble position; x3 b represents an x coordinate that is of the third bubble position in the Cartesian coordinate system and that is obtained through calculation by using Ubij as a reference, and y3 b represents a y coordinate that is of the third bubble position in the Cartesian coordinate system and that is obtained through calculation by using Ubij as a reference; Kxbij represents the second x parameter; and Kybij represents the second y parameter.
The calibration method according to claim 4, characterized by further comprising: performing weighted averaging processing on (x3 a , y3 a ) and (x3 b , y3 b ) to obtain coordinates (x3, y3) used to represent the third bubble position.
The calibration method according to claim 1, characterized by further comprising: performing weighted averaging processing on the first photoelectric signal and the second photoelectric signal to obtain a photoelectric signal Udij existing when the bubble is located at a center position, and obtaining the third bubble position through calculation by using the following formula: wherein i=1: m indicates a first to an m th light-emitting apparatuses in the electronic bubble level; j=1: n indicates a first to an n th receiving apparatuses in the electronic bubble level; Uij indicates a third photoelectric signal of an i th light-emitting apparatus that is received by a j th receiving apparatus when the bubble is at the third bubble position; x3 d represents an x coordinate that is of the third bubble position in a Cartesian coordinate system and that is obtained through calculation by using Udij as a reference, and y3 d represents a y coordinate that is of the third bubble position in the Cartesian coordinate system and that is obtained through calculation by using Udij as a reference; Kxdij represents a third x parameter; and Kydij represents a third y parameter.
The calibration method according to any one of claims 1 to 6, characterized in that the at least two target positions are evenly distributed on a wall circumference of the side wall.
The calibration method according to any one of claims 1 to 7, characterized in that the first target position and the second target position are symmetrically disposed.
The calibration method according to any one of claims 1 to 8, characterized by further comprising: obtaining a current position of the bubble through calculation by using the calibrated bubble position calculation model.
The calibration method according to any one of claims 1 to 9, characterized by further comprising: adjusting the tilt state of the electronic bubble level, so that a bubble position displayed on a display reaches a center position; in this case, obtaining a fourth photoelectric signal of the electronic bubble level, wherein the fourth photoelectric signal corresponds to a center bubble position at which the bubble is located in the center of the electronic bubble level; and obtaining the third bubble position through calculation based on the third photoelectric signal and the fourth photoelectric signal.
The calibration method according to claim 10, characterized in that the step of obtaining the third bubble position through calculation based on the third photoelectric signal and the fourth photoelectric signal comprises: performing calculation by using the following formula: wherein i=1: m indicates the first to the m th light-emitting apparatuses in the electronic bubble level; j=1: n indicates the first to the n th receiving apparatuses in the electronic bubble level; Uij indicates the third photoelectric signal of the i th light-emitting apparatus that is received by the j th receiving apparatus when the bubble is at the third bubble position; Uoij indicates a fourth photoelectric signal of the i th light-emitting apparatus that is received by the j th receiving apparatus when the bubble is at the center bubble position; x3 o represents an x coordinate of the third bubble position in the Cartesian coordinate system, and y3 o represents a y coordinate of the third bubble position in the Cartesian coordinate system;Kxoij represents a fourth x parameter; and Kyoij represents a fourth y parameter.
The calibration method according to claim 4, characterized by further comprising performing confidence level check on a model parameter, wherein the step of performing confidence level check on a model parameter comprises: obtaining a confidence level by checking whether redundant data conflicts with each other, and determining, based on the confidence level, to partially calibrate, fully calibrate, or skip calibrating a model parameter of the bubble position calculation model, wherein the redundant data comprises a photoelectric signal that does not need to participate in calculation of the first parameter and the second parameter.
The calibration method according to claim 6, characterized by further comprising performing confidence level check on a model parameter, wherein the step of performing confidence level check on a model parameter comprises: obtaining a confidence level by checking whether redundant data conflicts with each other, and determining, based on the confidence level, to partially calibrate, fully calibrate, or skip calibrating a model parameter of the bubble position calculation model, wherein the redundant data comprises a photoelectric signal that does not need to participate in calculation of the third x parameter and the third y parameter.
The calibration method according to claim 11, characterized by further comprising performing confidence level check on a model parameter, wherein the step of performing confidence level check on a model parameter comprises: obtaining a confidence level by checking whether redundant data conflicts with each other, and determining, based on the confidence level, to partially calibrate, fully calibrate, or skip calibrating a model parameter of the bubble position calculation model, wherein the redundant data comprises a photoelectric signal that does not need to participate in calculation of the fourth x parameter and the fourth y parameter.
A calibration apparatus for an electronic bubble level, wherein the electronic bubble level has a housing comprising a side wall, wherein a liquid and a bubble are arranged inside the side wall, the side wall of the housing has at least two target positions, and the at least two target positions comprise a first target position and a second target position, characterized in that the apparatus comprises: a memory configured to store instructions executable by a processor; a controller configured to control a tilt state of the electronic bubble level; and the processor configured to execute the instructions to implement the calibration method according to any one of claims 1 to 14.
The calibration apparatus according to claim 15, characterized by further comprising a tilt sensor configured to detect a tilt degree of the electronic bubble level, and feed back the tilt degree to the controller, to instruct the controller to control the tilt state of the electronic bubble level.
The calibration apparatus according to claim 16, characterized in that the tilt sensor comprises a MEMS accelerometer.
The calibration apparatus according to any one of claim 15 to 17, characterized in that the electronic bubble level is disposed in an electronic device, and the controller is configured to control the tilt state of the electronic bubble level by controlling a tilt state of the electronic device.
A computer-readable medium storing computer program code, wherein when the computer program code is executed by a processor, a calibration method according to any one of claims 1 to 14 is implemented.

Description

CALIBRATION METHOD AND APPARATUS FOR ELECTRONIC BUBBLE LEVEL, AND COMPUTER-READABLE MEDIUM BACKGROUND OF THE INVENTION Technical Field The present invention mainly relates to the field of precision measurement instruments, and in particular, to a calibration method and apparatus for an electronic bubble level, and a computer-readable medium. Background Art Many precision measurement instruments need to be in a defined horizontal state for working properly. For example, a weighing error of an electronic balance (weighing instrument) that works based on a gravity method is increased when the balance is tilted, and when the balance is tilted to a larger degree, the error is larger. A bubble level (spirit level) is usually used to assist in determining whether the instrument is horizontally aligned. The bubble level includes a sealed housing, and is incompletely filled with a liquid, leaving a bubble. The housing is provided with a transparent window, and a bubble position may be observed by using the transparent window. When the balance is tilted, the bubble position is shifted to a higher side. An electronic bubble level includes a physical bubble level, several photoelectric devices (alight-emitting device and a receiving device) , a signal processing unit, a calculation unit, a control unit, and the like. The light-emitting device and the receiving device are mounted around the physical bubble level. Light emitted by the light-emitting device is reflected and refracted after the light is irradiated on the bubble, and then is received by the receiving device. If the bubble position changes, an optical path between the light-emitting device and the receiving device also changes, so that a received photoelectric signal changes. The calculation unit may obtain a position of the bubble in the bubble level from the photoelectric signal through calculation based on a specific calculation model, and determine, based on the position, whether the bubble is located at a center position and a deviation degree to which the bubble is deviated from the center position, so that a tilt degree of a device configured with the electronic bubble level can be obtained. As the use time grows, the electronic bubble level has some drift, and therefore the electronic bubble level needs to be tuned and calibrated. One method for recalibrating an electronic bubble level is to move the bubble to a center reference position, so that an electronic bubble level system records a photoelectric signal existing when the bubble is located at the center reference position, to adjust and calibrate a model parameter and restore precision of the electronic bubble level to a best state. However, in some instruments, no window is specially arranged for the electronic bubble level, and a cover of the instrument needs to be opened to see an exact position of the physical bubble, so as to complete a maintenance task of adjustment and calibration. An operation of opening the cover of the instrument usually needs to be performed by professional maintenance personnel, and the instrument even needs to be returned to an original manufacturer. The process is troublesome and costly. Therefore, a method for adjusting and calibrating an electronic bubble level without opening a cover of an instrument equipped with the electronic bubble level and without observing a bubble position of a physical bubble level by using a window is required. SUMMARY In view of the technical problem to be solved by the present invention, an easy-to-operate and low-cost calibration method and apparatus for an electronic bubble level, and a computer-readable medium are provided. To solve the technical problem, the present invention provides a calibration method for an electronic bubble level, where the electronic bubble level has a housing, a liquid and a bubble are arranged inside a side wall of the housing, the side wall of the housing has at least two target positions, the at least two target positions include a first target position and a second target position, and the method includes: controlling a tilt state of the electronic bubble level, so that the electronic bubble level is in a first state, and in this state, the first target position is higher than the second target position, and the bubble comes into contact with the side wall; obtaining a first photoelectric signal of the electronic bubble level in the first state, where the first photoelectric signal corresponds to a first bubble position of the bubble; controlling the tilt state of the electronic bubble level, so that the electronic bubble level is in a second state, and in this state, the second target position is higher than the first target position, and the bubble comes into contact with the side wall; obtaining a second photoelectric signal of the electronic bubble level in the second state, where the second photoelectric signal corresponds to a second bubble position of the bubble; obtaining a third photoelectri