RU2475703C1 - Inclination angle sensor - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: inclination angle sensor includes a cylindrical chamber partially filled with non-conductive liquid and formed with inner cylindrical surface of the housing and two flat parallel plates with electrodes. Inner cylindrical surface of the housing has stepped shape and smaller diameter in the middle part of the housing and larger diameter in the sections adjacent to conditional plates of the cylinder bases. Plates with electrodes are installed on the housing projections formed with difference in its diameter and pressed to them by means of the cover plates closing the housing on the side of its bases. Electrodes are arranged on outer surface of plates relative to the chamber and connected to an electronic circuit arranged in the above cover plates on both sides of cylindrical chamber. Electronic circuit includes converter of output signals and microcontroller related to it and performing the functions of digital processing device of output information and shaper of input pulses. At that, converter of output signals includes amplifier, filter cartridge and analogue-to-digital converter.

EFFECT: improvement of compactness and reliability of the device; provision of high measurement accuracy.

5 cl, 8 dwg

Description

FIELD OF THE INVENTION

The invention relates to instrumentation, and more particularly to devices for determining the spatial position of objects relative to the horizon. The device can be used in geodesy, construction, mining, in the oil and gas industry when drilling wells, in monitoring and control systems for various moving objects, in burglar alarm and seismic monitoring devices.

State of the art

A known sensor angle of deviation of the object from a horizontal position (see patent for invention RU 2215992, IPC G01C 9/20, G01C 9/06, publ. 10.11.2003), containing a sealed chamber, half filled with dielectric fluid, formed by a sleeve and two electrodes in the form of plates, two more output electrodes are fixed inside the chamber. The said sensor is a sensor, a sensitive element, for the processing of the output signals of which the use of additional converting and computing devices is required.

A device is known for a digital tilt angle meter (see Utility Model Patent No. 50298, IPC G01C 9/06, published December 27, 2005), which comprises a tilt angle sensor and a housing inside which an electronic circuit for converting the sensor output signal including a microcontroller is located with the ability to control the measurement modes using the keyboard located on the outer surface of the housing along with a liquid crystal display. The sensor is located outside the housing with an electronic circuit and is connected to the latter via an electric cable.

Known capacitive tilt sensor (see patent EP 0492330, IPC G01C 9/20, G01C 9/06, publ. 07/01/1992 g) containing a sealed cylindrical tank, half filled with liquid with high dielectric constant, at the ends of which are placed plates with electrodes forming, in conjunction with the reservoir, the sensor element. Elements of the electronic signal processing circuitry are located on the same plates, outside the electrode area, outside the reservoir. The device is not compact, has poor noise immunity and insufficient resistance to various kinds of influences.

As the closest in the presence of similar structural features analogue to the claimed technical solution, a device for measuring the angle of inclination (inclinometer), disclosed in US patent 4528760, IPC G01C 9/06, publ. 07/16/1985 According to the aforementioned patent, the device for measuring the angle of inclination contains a sensing element in the form of a cylindrical chamber partially filled with liquid, formed by the inner cylindrical surface of the drum-type housing and two round plane-parallel plates with electrodes on the outer relative to the sealed chamber surface. The electrodes are connected to an electronic circuit of the device, including an output signal converter connected to a digital information processing device.

The sensing element and components of the electronic circuit according to one embodiment of the device can be placed in a common casing-case. According to another embodiment, part of the components of the electronic circuit can be transferred to the main control unit.

The disadvantages of the known device include large dimensions, insufficient noise immunity and reliability of the sensor. In addition, the used circuit for connecting the electrodes and processing the recorded signals allows you to only monitor the value of the angle of inclination and, comparing it with the limit values, issue an alert signal when the latter are exceeded.

Disclosure of invention

The task to which the invention is directed is the creation of an intelligent tilt angle sensor of increased reliability and compactness, providing high measurement accuracy.

The problem is solved due to the fact that in the tilt sensor containing a cylindrical chamber partially filled with a non-conductive fluid, formed by the inner cylindrical surface of the housing and two plane-parallel plates with electrodes on the outer surface relative to the camera connected to an electronic circuit including an output signal converter associated with a digital information processing device according to the claimed invention, the inner cylindrical surface of the housing non-stepped shape, with a smaller diameter in the middle part of the body and a large diameter - in areas adjacent to the conditional planes of the base of the cylinder, plates with electrodes are mounted on ledges of the body formed by the difference in its diameter, and are drawn to them by means of covers that cover the body from the side of the bases , in the covers are formed seating surfaces for installing printed circuit boards with elements of an electronic circuit including a microcontroller that acts as a digital information processing device and is made with the ability to form input pulses.

The above set of distinctive features of the claimed device allows to obtain the following positive technical results:

- increase the compactness of the device;

- increased reliability;

- improvement of noise immunity;

- increase the reliability of measurement results;

- increase manufacturability;

- improving the convenience of operation and maintenance.

Distinctive features from the closest analogue of the proposed sensor are the design of the housing with a stepped inner surface, the presence of covers that cover the housing from the ends of the covers and their design, as well as the construction of an electronic circuit based on a microcontroller.

Unlike the prototype, plates with electrodes are installed inside the housing, which is ensured by its stepped inner surface, and are tightened by covers that are fixed in the housing, preferably rolled into the housing.

The housing, together with the covers, not only ensures the formation and operation of the sensor’s sensitive element (SE) of the sensor - a sealed cylindrical chamber with non-conductive liquid, the plates with electrodes are placed at the ends of them, but also provide a compact placement of all components of the sensor’s electronic circuit, for which landing surfaces for printed circuit boards carrying electronic circuit elements.

The use of a microcontroller made it possible to drastically reduce the dimensions of the measuring and converting system (electronic circuitry of the sensor) and made it possible to place it in one compact case with a sensitive element.

As a result, the proposed tilt angle sensor is a compact complete device, from the output of which ready-made measurement data are taken in a form convenient for calculations, for visualization, and for use in control systems of a moving object, the position angle of which was measured. The device is distinguished by its readiness to connect to automated data collection and control systems without the need for additional converting devices.

Due to the placement of electronic circuit elements in the housing covers on both sides of the sealed chamber, the length of the wired communication lines is reduced to a minimum, which, combined with the analog and digital filtering of the signal by the electronic circuit of the device, allows to minimize losses and increase the reliability of measurement information.

All elements of the device are not only compactly placed in a single case, but also rigidly fixed in it: the covers are fixed relative to the case, and boards with electronic circuit elements are rigidly fixed in the covers. Due to the absence of long wires and moving parts, the design of the sensor has increased stability with respect to any loads, including vibration and shock, which ensures the reliability of the sensor under any operating conditions.

The proposed sensor design is simple and manufacturable, allows, if necessary, repair and replacement of individual elements, and is characterized by ease of maintenance and operation.

The microcontroller performs both the function of the driver of the input pulses supplied to the potential electrodes of one plate and the function of digitally processing the output information that has undergone primary processing in the converter of output signals. Due to the fact that the mentioned functions are performed by one device, the accuracy of information processing is increased, and the possibilities of measurements are expanded. So, for example, the microcontroller allows you to change the direction of the reference angle.

The microcontroller provides the organization of communication with external devices, for example, with the aim of transmitting measurement information to the object control system, or to the head computing device of the device, where the inventive sensor can be included as part.

The printed circuit boards with electronic circuit elements are preferably located on the outside of the covers, in which holes are made for the connecting wires connecting the electrodes and the electronic circuit. In this case, the metal case with metal covers rolled in it forms a closed protective shield around the sensitive element, which excludes the influence of the electric part of the sensor on it, contributes to high noise immunity and increase the reliability of the measurement information.

Mentioned placement is preferred, but does not limit the possibilities of another implementation of the inventive device. So, for example, mounting locations for electronic circuit elements can be formed inside the covers, or even on the inner surface of the cover, however, in the latter case, the protective shield mentioned above is missing.

Unlike the prototype, the claimed sensor uses several potential electrodes placed on the first plate, and one removable electrode located on the second plate. Potential electrodes are made in the form of plating sections in the form of identical sectors into which a common plating circle is made on the surface of the first plate, with each potential electrode connected to the output of the microcontroller.

The removable electrode is made in the form of a solid metallization circle on the surface of the second plate and is connected to the input of the output signal converter.

This design of the electrodes makes it possible to use the phase method of signal processing, while the phase of the output signal varies linearly from 0 to 360 electrical degrees when the position of the sensor housing changes from 0 to 360 angular degrees.

The number of sectors is 2 ⁿ , where n≥3, preferably 3, 4, 5. The number of electrodes less than 8 does not provide the necessary measurement accuracy. Increasing the electrodes to 64 is technologically difficult to implement.

The output signal converter includes an amplifier, a filter cell and an ADC, made, for example, on the basis of a comparator.

For a better understanding of the essence of the proposed solution, the following is an example of a specific implementation of the sensor, illustrated by drawings.

Brief Description of Drawings

The design and operation of the sensor are illustrated by drawings, where

figure 1 shows the sensor, a General view with a partial section;

figure 2 - case, General view;

figure 3 - section aa from figure 2, is rotated;

figure 4 - the first plate with potential electrodes,

figure 5 - the second plate with a removable electrode,

figure 6 is a cover, a side view with a partial section,

Fig.7 is a view In from Fig.6, for the first (a) and second cover (b),

in Fig.8 is a schematic diagram of a sensor.

The implementation of the invention

The proposed inclination angle sensor contains (see Fig. 1) a drum-type housing 1, closed by caps 2, a sealed cylindrical chamber 3, partially filled with a non-conductive fluid 4, formed by the inner cylindrical surface of the housing 1 and two plane-parallel plates 5 with electrodes on the outer, relative to the camera 3 surface connected to the electronic circuit of the sensor.

The inner cylindrical surface of the housing 1 (see FIGS. 2, 3) is made in a stepped form: with a smaller diameter (D1) in the middle part of the housing and a larger diameter (D2) in areas adjacent to the conditional planes of the cylinder bases formed by the said surface. The plates 5 are mounted on the ledges 6 formed by the stepped form of the housing and are pressed to them by covers 2 rolled into the housing 1, which ensures the tightness of the chamber 3. To allow rolling on the outer surface of the housing 1, thin-walled cylindrical protrusions 7 are formed.

Between the plate 5 and the lid 2 pressing it, a rubber sealing ring 8 can be installed.

The plates 5 are made of dielectric ceramic material, have the same size and round shape (see figures 4 and 5). On the outside, relative to the chamber 3, the side of the plates is metallized in the form of a concentrically arranged circle. On the plate 5 ', the metallization circle is divided by gaps into 16 sectors, each of which forms a potential electrode 9. On the plate 5 ", the metallization has the shape of a solid circle forming one removable electrode 10.

On the outside on the lids 2 (see Fig.6 and 7) made collars 11, forming a volume and seating surface for placement of printed circuit boards 12 with elements of an electronic circuit. The printed circuit boards 12, made of round shape from the PCB, are mounted on the protrusions formed by the stepped inner surface of the flanges 11 of the lids 2 and secured to them by crimping the edges of the flange in several places (see figure 1).

In the covers 2, holes 13 are made for the wires 14 connecting the electrodes of the plates 5 with the elements of the electronic circuit.

The sensor electronic circuit (see Fig. 8) includes the so-called shaper cell 15 and the output signal converter cell 16. The shaper cell 15 contains a microcontroller (MK) and an interface converter (I) located on a printed circuit board 12 installed in the cover 2 'from the side of the plate 5' with potential electrodes 9. The outputs P1-P16 of the microcontroller (MK) are connected to potential electrodes 9.

The output signal converter cell 16 includes pre-amplifier (U) connected in series, three band-pass filters (F1, F2 and F3), a limit amplifier (UO) and a comparator (K) located on the second board 12 installed in the cover 2 ". Input pre-amplifier (U) is connected to a removable electrode 10. The output of the comparator (K) is connected to the information input of the microcontroller (MK).

The sensor is a capacitive converter. The presence of 16 potential electrodes on the first plate makes it possible to use the phase processing method, while the phase of the output signal varies linearly from 0 to 360 el. hail. when changing the position of the sensor housing from 0 to 360 ° angular.

It is possible to increase the number of sectors (potential electrodes) to 32 or more, which will further increase the accuracy of measurements, while changing the number of potential electrodes will only increase the number of outputs of the microcontroller and adjust its program, in general, the device design will remain unchanged. Circuitry methods for increasing the number of inputs / outputs of the microcontroller and the associated changes in the program of its work are well known.

The operation of the sensor is as follows.

After power is supplied, the microcontroller (MK), in accordance with the program recorded earlier in its memory, sets up its internal equipment and either expects a request for measurement from the interface converter (I), or performs measurements in accordance with the program. The interface is used to coordinate levels between the external RS-485 interface and the MK microcontroller.

After receiving the request, the microcontroller generates rectangular voltage pulses, starting from the output of P1 and then to P16, shifted relative to each other in time, the pulse duration at each output of P is T / 2, where T is the pulse propagation period. The voltage pulses from the outputs P1-16 of the microcontroller are supplied to the corresponding potential electrodes 9 of the plate 5 ', where voltage pulses are also generated, shifted relative to each other in time.

The plate electrodes together with the sealed chamber 3 between them form sixteen capacitors, the capacity of each of which depends on the presence of liquid 4 between the electrodes. The more liquid, the greater the capacity of this capacitor.

The signal from the removable electrode 10, amplified by a low-noise precision amplifier (U) and filtered by a three-link bandpass filter (F1-FZ), is fed to a comparator (K), which selects the phase of the signal with respect to the beginning of a series of pulses supplied to potential electrodes by the microcontroller MK. The selected phase contains information about the angular position of the liquid relative to the electrodes. The signal from the comparator is transmitted to the microcontroller, which processes and averages the received information. Measurement data in digital form is transmitted via the RS-485 interface to an external device, or stored in the MK memory.

The case with lids rolled in it serves as a protective screen, which prevents the influence of random stray containers on the readings of the sensitive element.

The sensor has a linear dependence of the output signal on the angle of inclination (± 180 °) of the sensor housing in one, the so-called the working plane, and practically does not change the readings in another plane perpendicular to it (non-working). In this case, the signal weakly depends on temperature.

To determine the position of the object in space, two angle sensors are used, located at 90 ° to each other, i.e. in two mutually perpendicular planes. For fixing on the object or in the device, on the sensor housing 1 there is a mounting surface 17 and holes 18 for fixing screws.

The proposed precision, small-sized, intelligent sensor provides accurate measurement of the angle of inclination relative to the horizon and can be used in geophysical equipment to determine the heel of various vehicles and high-rise structures, deform various supports and beams, determine the direction of drilling of oil and gas wells, to control the angle tilt of roads and railways, to control the position of the working body in various machines, to determine the angular displacement of various kinds of rotation objects in the alarm systems and seismic monitoring, etc.

Claims (5)

1. The tilt angle sensor containing a cylindrical chamber, partially filled with a non-conductive fluid, formed by the inner cylindrical surface of the housing and two plane-parallel plates with electrodes on the outer, relative to the camera, surface connected to an electronic circuit including an output signal converter connected to a digital information processing device , characterized in that the inner cylindrical surface of the housing is made of a stepped shape, with a smaller diameter in the middle h the body with a large diameter in the areas adjacent to the conditional planes of the base of the cylinder, the plates with electrodes are mounted on the ledges of the body formed by the difference in its diameter, and are pressed to them by means of covers that cover the body on the base side, the covers for mounting printed circuit boards are formed in the covers with elements of an electronic circuit including a microcontroller that performs the functions of a digital information processing device and is configured to generate input pulses, while photoelectret output signals comprises amplifier, filter and ADC cell. 2. The sensor according to claim 1, characterized in that the housing and the covers are made of metal, while the covers are rolled into the housing. 3. The sensor according to claim 1, characterized in that the seating surfaces for installing printed circuit boards with electronic circuit elements are formed on the outer surface of the covers, while the covers have holes for wires connecting the electrodes to the electronic circuit elements. 4. The sensor according to claim 1, characterized in that the electrodes of each of the plates are made in the form of metal plots on its surface in the form of a circle, wherein the metallization circle of the first plate is divided into equal sectors forming potential electrodes connected to the outputs of the microcontroller, and the circle metallization of the second plate is made integral and forms a removable electrode connected to the input of the output signal converter. 5. The sensor according to claim 4, characterized in that the number of sectors is 2 ⁿ , where n≥3.

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