CN112595382A - Liquid level sensor suitable for service robot and compensation algorithm thereof - Google Patents
Liquid level sensor suitable for service robot and compensation algorithm thereof Download PDFInfo
- Publication number
- CN112595382A CN112595382A CN202011210088.1A CN202011210088A CN112595382A CN 112595382 A CN112595382 A CN 112595382A CN 202011210088 A CN202011210088 A CN 202011210088A CN 112595382 A CN112595382 A CN 112595382A
- Authority
- CN
- China
- Prior art keywords
- liquid level
- cavity
- pipeline
- service robot
- level sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
- G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
Abstract
A liquid level sensor suitable for a service robot and a compensation algorithm thereof belong to the technical field of liquid level detection in robots. The liquid level sensor and the compensation algorithm thereof provided by the invention have the advantages of good stability, high accuracy and capability of realizing linear measurement and are suitable for the service robot. A liquid level sensor suitable for a service robot is characterized in that a hollow pipeline is arranged on the side wall of a cavity, the upper inlet and the lower inlet of the hollow pipeline are communicated with the cavity, a sensor circuit board is arranged on the side wall of the middle pipeline, a Tesla valve is arranged inside the lower pipeline, and liquid is contained in the cavity. A compensation algorithm suitable for a liquid level sensor of a service robot is characterized in that a capacitance sensing unit detects the height of liquid in a cavity in real time; the acceleration sensing unit detects the gravity acceleration of the cavity in real time; calculating the component of the current gravitational acceleration on a three-axis coordinate system, and calculating an inclination angle according to the component; and calculating the actual liquid level according to the inclination angle. The liquid level detection device is mainly used for detecting the liquid level of liquid in the robot.
Description
Technical Field
The invention belongs to the technical field of detection of liquid level in a robot, and particularly relates to a liquid level sensor suitable for a service robot and a compensation algorithm thereof.
Background
With the continuous development of the technology, the application field of the service robot is more and more extensive. In some application scenarios, a robot is required to carry a small amount of liquid substances (generally below 20L), and meanwhile, the liquid level measurement also becomes an essential function. At present, two methods for measuring the liquid level in the service robot are mainly adopted, namely a mass method and a switching value method. The mass method is to weigh the level + container, although the measurement is relatively mature, the structural requirements are high and the container needs no damping in the measurement direction. Otherwise the measurement will have some error. The switching value method mainly utilizes a floater to detect, is accurate but nonlinear, and can only detect a plurality of points.
Therefore, a liquid level sensor suitable for a service robot and a compensation algorithm thereof, which have good stability and high accuracy and can realize linear measurement, are needed.
Disclosure of Invention
Aiming at the defects of poor stability, low accuracy and incapability of linear measurement of the conventional liquid level detector, the invention provides the liquid level sensor which has good stability and high accuracy and can realize linear measurement and is suitable for the service robot and the compensation algorithm thereof.
The technical scheme of the invention is as follows:
the invention relates to a liquid level sensor suitable for a service robot, which comprises a sensor circuit board, a cavity and a Tesla valve, wherein a hollow pipeline is arranged on the side wall of the cavity, the upper inlet and the lower inlet of the hollow pipeline are communicated with the cavity, the hollow pipeline is divided into an upper pipeline, a middle pipeline and a lower pipeline, the upper pipeline is an upper flow passage, the sensor circuit board is arranged on the side wall of the middle pipeline, the Tesla valve is arranged in the lower pipeline, and liquid is filled in the cavity.
Further: the sensor circuit board comprises a power supply unit, a main control unit, a capacitance sensing unit, an acceleration sensing unit and a communication interface, wherein the input end of the power supply unit is connected with an external power supply, the output end of the power supply unit is connected with the input end of the main control unit, the main control unit is respectively in two-way connection with the capacitance sensing unit and the acceleration sensing unit, and the main control unit is in two-way connection with the communication interface.
Further: the middle pipeline is a glass tube, and the sensor circuit board is vertically fixed on the outer wall of the glass tube.
The invention relates to a compensation algorithm of a liquid level sensor suitable for a service robot, which comprises the following steps:
s1, detecting the height of the liquid in the cavity in real time by the capacitance sensing unit;
s2, constructing a three-axis coordinate system according to the acceleration sensing unit, and detecting three-axis acceleration components of the gravity acceleration on the coordinate axis in real time by the acceleration sensing unit;
s3, calculating the inclination angle of the box body according to the current triaxial acceleration component;
and S4, calculating the actual liquid level according to the inclination angle.
Further: the calculation formula of the liquid height is as follows:
in the formula, epsilon0A dielectric constant of vacuum;
in the air, epsilon is 1;
a is the overlapping area of the polar plates, m2；
Delta is the distance between two parallel polar plates, m.
Further: the calculation formula of the actual liquid level is as follows:
L＝L1+(Ltanα)/2
L1is the current measured level and L is the actual level.
The invention has the beneficial effects that:
the invention relates to a liquid level sensor suitable for a service robot and a compensation algorithm thereof. The scheme is continuous in liquid level detection and has good adaptability. In addition, aiming at the problem of the oscillation of liquid in the movement of the robot, a buffer channel is introduced in the design, so that the oscillation can be buffered, and the measurement is more stable. In addition, in order to solve the problem of high requirement of the cavity mounting structure, a compensation algorithm is designed, so that the requirement of the liquid level sensor on the cavity mounting structure is reduced, and the accuracy of measurement is ensured. After the technology is adopted, the installation structure requirement of the liquid cavity is relatively loose, and higher stability and accuracy can be ensured.
Drawings
FIG. 1 is a block diagram of a liquid level sensor configuration;
FIG. 2 is a block diagram of the electrical configuration of the level sensor;
FIG. 3 is a schematic view of a level sensor compensation;
in the figure, 1 is a sensor circuit board, 2 is an upper flow channel, 3 is a cavity, 4 is liquid, 5 is a glass tube, and 6 is a Tesla valve.
Detailed Description
The technical solutions of the present invention are further described below with reference to the following examples, but the present invention is not limited thereto, and any modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Example 1
The embodiment is described with reference to fig. 1, in the embodiment, the liquid level sensor suitable for a service robot in the embodiment includes a sensor circuit board 1, a cavity 3, and a tesla valve 6, a hollow pipeline is disposed on a side wall of the cavity 3, upper and lower inlets of the hollow pipeline are both communicated with the cavity 3, the hollow pipeline is divided into an upper pipeline, a middle pipeline, and a lower pipeline, the upper pipeline is an upper flow channel 2, the sensor circuit board 1 is disposed on a side wall of the middle pipeline, the tesla valve 6 is disposed inside the lower pipeline, and the cavity 3 contains liquid 4. The purpose of this is: the principle of communicating vessels is mainly utilized to lead the liquid in the cavity 2 into a slender glass tube (made of non-conductive materials), the principle of capacitance induction is utilized again, the dielectric constants of the medium with liquid and the medium without liquid level are different, the detected difference of capacitance is converted into different liquid levels, and the process of converting liquid level signals into electric signals is realized. In order to solve the instability in the movement of the robot, the bottom of the communicating vessel is designed into a Tesla valve structure. Thus, the flow of liquid from the chamber 2 to the other end of the connector is impeded by the Tesla valve, so that the wave motion is attenuated.
Example 2
The present embodiment is described with reference to fig. 2 and embodiment 1, and in the present embodiment, a liquid level sensor suitable for a service robot related to the present embodiment includes a power supply unit, a main control unit, a capacitance sensing unit, an acceleration sensing unit, and a communication interface, an input end of the power supply unit is connected to an external power supply, an output end of the power supply unit is connected to an input end of the main control unit, the main control unit is respectively connected to the capacitance sensing unit and the acceleration sensing unit in a bidirectional manner, and the main control unit is connected to the communication interface in a bidirectional manner. The purpose of this is: in order to allow a large tolerance for the installation of the chamber 2, because of the acceleration sensor, the inclination angle of the chamber 2 is calculated by the sensor and the liquid level is compensated by the calculation. The sensor circuit board is composed of a power supply unit, a main control unit, a capacitance sensing unit, an acceleration sensing unit and an external interface.
Example 3
The present embodiment is described with reference to embodiment 2, and in the present embodiment, the liquid level sensor suitable for a service robot according to the present embodiment is a glass tube 5, and the sensor circuit board 1 is vertically fixed on an outer wall of the glass tube 5. The purpose of this is: the circuit board is tightly attached to the outer wall of the glass tube. The liquid level sensor is vertically fixed on the outer wall of the cavity.
Example 4
The present embodiment is described with reference to fig. 2 and embodiment 1, and in the present embodiment, the present embodiment relates to a compensation algorithm for a liquid level sensor of a service robot, which includes the following steps:
s1, detecting the liquid height in the cavity 3 in real time by the capacitance sensing unit;
the calculation formula of the liquid height is as follows:
in the formula, epsilon0A dielectric constant of vacuum;
in the air, epsilon is 1;
a is the overlapping area of the polar plates, m2；
Delta is the distance between two parallel polar plates, m;
s2, constructing a three-axis coordinate system according to the acceleration sensing unit, and detecting three-axis acceleration components of the gravity acceleration on the coordinate axis in real time by the acceleration sensing unit; the acceleration sensing unit detects the three-axis acceleration of the cavity (3) in real time;
s3, calculating the inclination angle of the box body according to the current triaxial acceleration component; the normal default gravity acceleration is a fixed value (9.8m/s2), and the inclination angle of the box body is calculated according to the component of the current gravity acceleration on the three-axis coordinate system where the sensor is located;
and S4, calculating the actual liquid level according to the inclination angle.
The compensation of the inclination angle has a limit condition, and only the error of the surface direction of the sensor is compensated. For example, the sensor is located on the W-plane, and the cavity has a deviation in the X-axis direction.
And (3) calculating the inclination angle:
because the gravity acceleration is always vertical downwards, after the cavity is deviated along the X axis, the liquid level sensor can detect acceleration values in the X axis and the Z axis. These two values are the components of the gravitational acceleration in the coordinate system in which the level sensor is located.
The inclination angle of the cavity along the Z axis can be calculated by a trigonometric function.
The tilting direction can be judged by the positive and negative values of the acceleration value in the X-axis direction. The component of the gravitational acceleration in the direction of the axis X on which the sensor is located is negative in the illustration, whereas the component in the direction of the axis X on which the sensor is located is positive if the direction of the inclination is opposite.
The calculation formula of the actual liquid level is as follows:
L＝L1+(Ltanα)/2
if the pouring direction of the cavity 3 is opposite:
L＝L1-(Ltanα)/2
L1is the current measured level and L is the actual level.
The working process is as follows:
in the presence of liquid in the chamber 2, the liquid passes through the communicating vessels to the elongated glass tube. The process is relatively gentle a bit because of the tesla valve. Until the position of the liquid in the chamber 2 coincides with the position of the liquid in the elongated glass tube, the liquids no longer flow into each other. The electrical part of the liquid level sensor then detects the liquid level in the elongated glass tube and, after a compensation algorithm, obtains the final liquid level.
The electrical structure block diagram of the liquid level sensor is shown in FIG. 2:
in addition to the basic power supply and communication units, the level sensor comprises an MCU unit (microcontroller), a capacitive sensing unit and an acceleration sensor unit.
For liquid level detection, the capacitance sensing unit comprises a long electrode plate, and the capacitance of the plate capacitor is equal to that of the plate capacitor under the condition of neglecting the edge effect
In the formula, epsilon0Dielectric constant of vacuum,. epsilon0＝8.854×1012F·m-1；
Epsilon is the relative dielectric coefficient of the medium between the polar plates, and in air, epsilon is 1;
a-overlapping area of the plates, m2；
Delta-the distance between two parallel plates, m.
With δ and ε unchanged, A changes will result in C changes. And a is referred to herein as the liquid level. The change in liquid level can be reflected in a change in capacitance. A simple correction is then made to obtain a continuous measurement of the liquid level.
Note: the maximum liquid level length, electrode plate width, liquid type are relevant here for the calibration.
This example illustrates a calibration algorithm for a level sensor in one case. In fig. 3, a cavity 2 with an inclination angle is arranged, and the liquid level sensor is tightly attached to the center of an X surface of the cavity 2. Assuming that the robot is stationary at this time, the level sensor is only affected by the acceleration of gravity. By calculating the components of the acceleration on the XYZ three axes, the tilt angle α of the chamber 2 can be obtained. Assuming that the level measured at this time is L1, the actual level is:
L1＝L1+(Ltanα)/2
if the pouring direction of the cavity 2 is opposite:
L1＝L1-(Ltanα)/2
the installation of the chamber 2 may be unaffected by the reverse tilt angle X. Similarly, if the liquid level sensor is placed in the center of other faces, the installation deviation in the direction can be corrected.
Claims (6)
1. The utility model provides a level sensor suitable for service robot, its characterized in that, it includes sensor circuit board (1), cavity (3) and tesla valve (6), be provided with the cavity pipeline on the lateral wall of cavity (3), the upper and lower entry of cavity pipeline all communicates with cavity (3), the cavity pipeline divide into pipeline, well pipeline and lower pipeline three-section, it is runner (2) to go up the pipeline, sensor circuit board (1) sets up on the lateral wall of well pipeline, tesla valve (6) set up inside the lower pipeline, splendid attire liquid (4) in cavity (3).
2. The liquid level sensor suitable for the service robot as claimed in claim 1, wherein the sensor circuit board (1) comprises a power supply unit, a main control unit, a capacitance sensing unit, an acceleration sensing unit and a communication interface, wherein an input end of the power supply unit is connected with an external power supply, an output end of the power supply unit is connected with an input end of the main control unit, the main control unit is respectively connected with the capacitance sensing unit and the acceleration sensing unit in a bidirectional mode, and the main control unit is connected with the communication interface in a bidirectional mode.
3. The liquid level sensor suitable for the service robot is characterized in that the middle pipeline is a glass tube (5), and the sensor circuit board (1) is vertically fixed on the outer wall of the glass tube (5).
4. A compensation algorithm for a level sensor adapted for use in a service robot, comprising the steps of:
s1, detecting the liquid height in the cavity (3) in real time by the capacitance sensing unit;
s2, constructing a three-axis coordinate system according to the acceleration sensing unit, and detecting three-axis acceleration components of the gravity acceleration on the coordinate axis in real time by the acceleration sensing unit;
s3, calculating the inclination angle of the box body according to the current triaxial acceleration component;
and S4, calculating the actual liquid level according to the inclination angle.
5. A compensation algorithm for a liquid level sensor of a service robot according to claim 4, characterized in that the calculation formula of the liquid level is:
in the formula, epsilon0A dielectric constant of vacuum;
in the air, epsilon is 1;
a is the overlapping area of the polar plates, m2；
Delta is the distance between two parallel polar plates, m.
6. The compensation algorithm for a liquid level sensor of a service robot according to claim 4, wherein the calculation formula of the actual liquid level is as follows:
L＝L1+(Ltanα)/2
L1is the current measured level and L is the actual level.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011210088.1A CN112595382A (en) | 2020-11-03 | 2020-11-03 | Liquid level sensor suitable for service robot and compensation algorithm thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011210088.1A CN112595382A (en) | 2020-11-03 | 2020-11-03 | Liquid level sensor suitable for service robot and compensation algorithm thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112595382A true CN112595382A (en) | 2021-04-02 |
Family
ID=75180526
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011210088.1A Pending CN112595382A (en) | 2020-11-03 | 2020-11-03 | Liquid level sensor suitable for service robot and compensation algorithm thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112595382A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114323085A (en) * | 2022-03-11 | 2022-04-12 | 武汉熠微科技有限公司 | Detection device for capacitive sensor |
| CN117723134A (en) * | 2024-02-07 | 2024-03-19 | 陕西建一建设有限公司 | High-precision measuring device for integrated river water level |
| CN117723134B (en) * | 2024-02-07 | 2024-05-03 | 陕西建一建设有限公司 | High-precision measuring device for integrated river water level |
-
2020
- 2020-11-03 CN CN202011210088.1A patent/CN112595382A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114323085A (en) * | 2022-03-11 | 2022-04-12 | 武汉熠微科技有限公司 | Detection device for capacitive sensor |
| CN114323085B (en) * | 2022-03-11 | 2022-05-20 | 武汉熠微科技有限公司 | Detection device for capacitance liquid level sensor |
| CN117723134A (en) * | 2024-02-07 | 2024-03-19 | 陕西建一建设有限公司 | High-precision measuring device for integrated river water level |
| CN117723134B (en) * | 2024-02-07 | 2024-05-03 | 陕西建一建设有限公司 | High-precision measuring device for integrated river water level |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN200986461Y (en) | Intelligent capacitance type liquid level measuring apparatus | |
| US8146421B2 (en) | Method and apparatus for sensing levels of insoluble fluids | |
| CN107490362A (en) | Monoblock type gas chamber piston apparatus for measuring degree of inclination and measuring method | |
| CN112595382A (en) | Liquid level sensor suitable for service robot and compensation algorithm thereof | |
| CN101839711A (en) | Portable digitalized high-precision tilt angle measuring instrument and measuring method | |
| CN105651248A (en) | Ceramic hydrostatic level | |
| CN201688837U (en) | Portable digital high-accuracy dipmeter | |
| CN108279194B (en) | Droplet concentration detection apparatus and detection method | |
| CN202033031U (en) | Digital level measuring device | |
| CN214504229U (en) | Horizontal adjusting equipment and system | |
| CN106323416B (en) | Capacitance type oil quantity measuring device | |
| CN201094001Y (en) | Rotor minim raising degree measuring instrument | |
| CN2219485Y (en) | Air bubble capacitor type levelness sensor | |
| CN105486378B (en) | A method of carrying out level gauging using plate capacitor formula sensor | |
| CN107677249A (en) | A kind of high-precision pendulum condenser type inclination measurement system and method for being used to monitor | |
| CN200955958Y (en) | Magnetic fluid horizontal sensor | |
| CN107121175B (en) | A kind of explosion-proof fuel oil measuring device of flush type | |
| CN203672371U (en) | Quartz flexure accelerometer based dipmeter | |
| CN2387520Y (en) | High precision capacitive sensing liquid level measurer | |
| RU209332U1 (en) | Pendulum sensing element | |
| JPH07243893A (en) | Pressure type liquid level measuring apparatus | |
| CN219390826U (en) | Main beam disturbance degree detection device | |
| CN211291439U (en) | Capacitive level detection device | |
| CN114199313A (en) | Input type liquid measuring system and measuring method | |
| CN115523977A (en) | Air pressure sensing liquid level meter and measuring method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |