WO2013157979A1

WO2013157979A1 - System for remote measurement and monitoring of physical magnitudes and method for remote measurement and monitoring of physical magnitudes

Info

Publication number: WO2013157979A1
Application number: PCT/RU2012/000305
Authority: WO
Inventors: Андрей Алексеевич ТЕРЕНТЬЕВ; Александр Кириллович КУЗЬМИН; Кирилл Евгеньевич СТОЛЯРОВ
Original assignee: Общество С Ограниченной Ответственностью "Энергосервис 2.0"
Priority date: 2012-04-19
Filing date: 2012-04-19
Publication date: 2013-10-24

Abstract

The invention relates to the field of measurement and monitoring equipment and is intended for measuring, monitoring and signalling a departure from a set range of physical magnitudes. The system for remote measurement and monitoring comprises: at least one sensor in the form of a passive oscillatory circuit comprising an inductance and a capacitance, wherein the magnitude for the capacitance and/or inductance changes depending on the measured magnitudes, thereby changing the resonant frequency of the sensor; an electromagnetic field generator; a parametric resonance detector; and a signal control and processing unit, wherein the inductance and the capacitance have a resonant frequency corresponding to a selected range. The capacitance is changed by virtue of a change in the inter-electrode space and/or by virtue of a change in the properties of the dielectric. The inductance is changed by virtue of a change in the shape of the conductor and/or by virtue of a change in the properties of the material in the direct vicinity of this conductor. The method consists in determining the value of a measured magnitude on the basis of the value of the resonant frequency of the sensor, which is dependent on the measured magnitude, which is determined by means of a generator having a frequency which is changed within a set range, wherein the detector is used to determine the correspondence of the frequency of the generator with the resonant frequency of the sensor, which corresponds to the value of the measured magnitude.

Description

System for remote measurement and control of physical quantities and method for remote measurement and control of physical quantities

The invention relates to the field of instrumentation and is intended for measuring, monitoring and signaling the exit from a given range of physical quantities (for example, pressure, temperature, humidity).

The invention can be used in various fields of technology and industry. For example, to monitor and warn of a decrease or difference in pressure in the pneumatic tires of a vehicle, to determine the place of penetration of moisture into the pipeline, the occurrence of damage or defects in the polyethylene sheath, and welded and butt joints. And also for measuring other physical quantities. The sensor has a simple design - it consists of capacitance and inductance, the parameters of one of which or both depend on one or several measured physical quantities.

Due to the wide scope of the invention, the analysis of analogues and its description is given on the example of a widespread system - a system for remote monitoring of tire pressure in automobile wheels (TirePressureMonitoringSystem - TPMS).

From the prior art in the field of operational remote monitoring of tire pressure, a system is known (Cl. RF - 25760, publ. 08/10/2011 1), aimed at the use of miniature electronic elements in standard structural solutions: a primary sensor mounted in a wheel and a display panel. Such a sensor consists of: a pressure sensor and a temperature sensor, analog-to-digital converters (ADP), a microprocessor of a transceiver (mini transceiver). A unidirectional or bidirectional communication channel with modulation and coding is used. The primary sensor is powered by a battery; as a rule, it is a lithium disposable battery. These systems work as follows: the pressure and temperature in the tires of automobile wheels is measured by sensitive elements and after digitizing and generating an information package by a microprocessor controller using a transceiver built into the sensor, information is transmitted via a radio channel to the display panel in the car. The display panel is also equipped with radio transmitting and receiving equipment and a microprocessor controller for processing signals received from sensors, calculating and displaying the measured pressure values of each wheel. For a similar scheme, for example, the Parkmaster TPMS-4-05 system is installed - a direct built-in tire pressure monitoring system of the 3rd generation (TPMS).

The disadvantage of the described analogue is the complexity of the design of the sensor itself, which is a complex electronic circuit that includes the electronic components described above, which significantly increases the cost and weight of the sensor, and also reduces the reliability of its operation. In addition, a sensor requires a battery (battery) located directly in the sensor. The battery has a limited service life, especially at low temperatures (in winter), and is mounted in the sensor as a non-separable element. After running out of battery life, the entire sensor needs to be replaced. In the case of using sensors located inside the tires, wheel disassembly is additionally required.

In contrast to this analogue, the proposed system:

1) has a very simple sensor design, which consists of only two elements of electronics - inductance and a variable capacitor and does not contain a battery, or an analog-to-digital converter, or a microprocessor, or a dedicated transmitter;

2) has a sensor that has significantly lower mass and cost, increased mechanical and temperature stability;

3) has another principle of remote transmission of information - the pressure is judged by the change in the parameters of the electromagnetic field that occurs when the emitted frequency coincides with the resonant frequency of the oscillatory circuit of the sensor. In turn, the resonant frequency of the oscillatory circuit through a variable capacitance and / or inductance depends on the measured physical quantity. In the case of measuring tire pressure, a variable capacitance may be used as described below. Thus, neither modulation, nor signal coding, nor a battery on the sensor are used.

A known monitoring system in tires without a power source (U.S. • Νι.200601 97655, 09/07/2006). This device uses the absorption and accumulation of microwave energy of the electromagnetic field in the sensor, then uses this energy to power the measurement, conversion, processing and encoded transmission circuits. In addition to the power circuit, the system is similar to the analogue discussed above.

A known pressure indicator (p. EPO 1 1043577, B60C23 / 00, publ. 1 1.10.2000). In this analogue, the sensitive element, the capacitance, is included in the RC circuit (resistive-capacitive circuit), which, in turn, is included in the electrical circuit of the generator fluctuations. A change in pressure leads to a change in capacitance, which, in turn, leads to a change in the oscillation frequency of the generator. Next, an alternating signal from the oscillation generator is fed to the microprocessor, which measures the frequency of oscillations, encodes the signal and sends it through a radio transmitter to a radio receiver located next to the wheel. In this system, the sensitive element - the capacitance, as in the analogs discussed above, has a galvanic connection with the microprocessor, there are also signal coding and a battery on the sensor.

The difference of the proposed system from this analogue is that the capacitance and inductance in the analogue are not elements of a generator, but form a passive oscillatory circuit, which is in the electromagnetic field generated by an external emitter, and galvanic coupling between such a passive oscillatory circuit and other elements is also not used. system.

A known method of radio frequency identification (RFID, p. US20080218352), which consists in determining the presence of a circuit with a predetermined fixed resonant frequency by generating an electromagnetic field and determining the parameters of such a field. The disadvantage is that the frequency of the circuit is fixed and does not depend on physical quantities, and therefore does not allow to organize the measurement of such quantities.

A device for signaling a decrease in pressure in the tire of a car is known (Cl. RF> 2149105, B60C23 / 02, publ. 05.20.2000), comprising an oscillating circuit mounted on the wheel of a vehicle, shunted by a switch in the event of an excessive decrease in pressure and connected inductively to the communication coil located on the vehicle body. The coil is connected to a generator through a current amplifier, and through a comparator to one of the inputs of a logic phase detector, the other input of which is connected to the generator output. The specified detector detects a change in the phase of the signal on the coil when bypassing the oscillatory circuit and turns on the detector.

The disadvantages of this device are discrete measurement, the presence of low-reliable mechanical parts (relays), and the unobservability of the sensor in case of failure (error of the second kind). Such a sensor detects only the presence of resonance when shunting the inductance by the capacitance (circuit closure by relay contacts). In fact, the device does not conduct an analog measurement, but discrete registration of a threshold value. In other words, this solution only allows you to track the critical limit of pressure reduction (on a yes-no basis). In contrast to this analog, the proposed system performs analog measurement in a wide range of pressure changes with high accuracy (commensurate with wired analog measurement systems), monitors the operability of the sensor and communication system, and also does not contain moving parts, such as relays.

As a prototype, a device was selected for monitoring tire pressure in a car (paragraph RF Jfs 94028846, В60С23 / 04, publ. 08.27.1996), containing a transceiver equipped with an inductance, by means of which a tunable resonant circuit mounted on the wheel rim is excited. The circuit includes inductance, pressure switch contacts and two capacitors. In parallel with the inductance of the resonant circuit, which can be performed as a single unit or divided into two sections, a diagnostic capacitance is constantly connected. A sensitive element here is also a mechanical relay.

This prototype, in contrast to the analogue discussed above (clause of the Russian Federation Ν ° 2149105), is supplemented with a control capacity, which makes it possible to determine the error of the second kind, i.e. allows you to diagnose a complete failure of the sensor or transceiver system.

The disadvantages of this prototype are similar to the disadvantages of the previous device, with the exception of determining errors of the second kind. A relay is also used as a sensing element. The authors additionally proposed the possibility of increasing the number of switched relay contacts and the number of constant capacitors connected to the circuit, which would lead to a change in the resonant frequency of the circuit in steps. However, this solution complicates and increases the cost of the design, reduces reliability, quality factor and range, without solving the problem of analog measurement.

Unlike the prototype, the proposed system for remote measurement of physical quantities has a simple and reliable design, performs analog measurement in a wide range of changes in physical quantities with fairly high accuracy, can have increased resistance to aggressive mechanical, temperature and other influences, and also does not contain mechanical parts. The sensitive element is a variable capacitance and / or inductance.

The technical result of the claimed invention is the creation of a simple, reliable and accurate system and method for remote monitoring and measurement of physical quantities, at least the following: pressure, temperature, humidity, allowing remotely conduct continuous analog measurement. In particular, the proposed system allows to improve the accuracy of measuring pressure in automobile tires in comparison with analogues using relays, and also to simplify the design, significantly reduce the cost, increase the reliability and service life of sensors in comparison with analogues using a microprocessor sensor.

The technical result is achieved by the following device and method: a system for remote measurement and control of physical quantities contains at least one sensor, which is a passive oscillatory circuit, consisting of an inductance and a capacitor connected in parallel to it. The value of the capacitance and / or inductance have the ability to vary depending on the measured physical quantities, thus changing the resonant frequency of the sensor. The system also contains an electromagnetic field generator for an oscillatory circuit, a parametric resonance detector, and a control and signal processing unit. The inductance and capacitance of the circuit are designed so that the resonant frequency of the sensor corresponds to the selected range of the system. The capacitance has the ability to change due to changes in the interelectrode space and / or due to changes in the properties of the dielectric from the measured physical quantity. As the capacitance, a variable capacitor can be used, consisting of plates of conductive material separated by air space or other elasto-plastic dielectric material, as well as a material with dielectric conductivity, depending on the measured physical quantity. Inductance can change due to a change in the shape of the conductor constituting the inductance and / or due to a change in the properties of the material in the immediate vicinity of such a conductor. An electromagnetic field and a transmitter-receiver circuit galvanically connected to an electromagnetic field generator and a parametric detector can be used as communication with the sensor. Also, two circuits can be used as communication with the sensor, one of which is receiving, the other is transmitting or an arbitrary combination of several such receiving, transmitting and receiving-transmitting circuits.

A method for remote measurement and control of physical quantities, which consists in determining the value of the measured physical quantity from the value of the resonant frequency of the sensor, depending on the measured physical quantity. The resonant frequency of the sensor is determined by creating an alternating electromagnetic field in the zone where the sensor is located using a generator. The frequency of such a field is changed by changing the frequency of the generator in a given range, while using a parametric detector that records the change in the amplitude-phase characteristics of the electromagnetic field, determine the coincidence of frequencies the electromagnetic field of the generator with the resonant frequency of the sensor, which corresponds to the value of the measured physical quantity.

Measurements can be carried out remotely (without using galvanic communication), in particular, the sensors can be located inside a moving object, on the object, or in close proximity to it. A similar use of a system with fixed objects is also possible. For example, to control pressure and temperature through the tank wall.

The system is distinguished by the absence in the design of the sensor of batteries, analog-to-digital conversion, microprocessor or other signal processing, coding and modulation. The main structural elements of the sensor - capacitance and inductance, are connected in parallel, of which one or both together are sensitive elements and continuously change when the measured physical quantities change, which allows for analog measurement. A combination of several sensitive elements in the sensor and / or several sensors is allowed, in particular, for compensation or joint measurement of several physical quantities. For example, for measuring tire pressure with regard to temperature compensation. Unlike analogues, the device is very simple and allows continuous monitoring of the values of physical quantities.

The invention is illustrated by the figure (Fig. 1), which depicts one of the variants of the scheme of the system of remote measurement and control of physical quantities.

The main components of the system of remote measurement and control of physical quantities are sensor 1, transceiver circuit 2, electromagnetic field generator 3 and parametric detector 4, control and signal processing unit 5. Generator 3 and detector 4 can use a common transceiver circuit made in the form of inductance L2 , and / or be combined, or use several independent circuits, each of which can be receiving, or transmitting or receiving-transmitting. In FIG. 1 shows a variant of the circuit when the generator 3 and the detector 4 use a common transceiver circuit L2.

Sensor 1 is a passive oscillatory circuit consisting of inductance L1 and capacitor C1, which are selected so that the resonant frequency of sensor 1 corresponds to the selected range of the system, while the capacitance and / or inductance may be able to vary depending on the measured physical quantity.

Variants of the sensor’s execution can be: a sensor, where the inductance is made similar to RFID tags sensors, in particular, a glued sensor (sensor sticker) on a flexible base, or a sensor with an inductance made along the perimeter of the bus, or a micro-sensor, or a sensor of increased area (for example, to increase the range), or a sensor with an inductance active in two or three dimensions. Other versions of the inductance, capacitance and sensor as a whole are possible, allowing measurements in this way.

In particular, when using a system for remote monitoring of tire pressure in automobile wheels, a container with an elastic dielectric and a movable plate can be used. When exposed to air pressure, the movable plate moves toward the fixed plate, as a result of which the capacitance of the variable capacitor C1 increases. With a decrease in pressure, due to the intrinsic elasticity and / or the elasticity of the dielectric separating plate, the plate moves away from the fixed plate and the capacitance decreases. Thus, the resonant frequency of the sensor 1 continuously depends on the change in the electric capacitance of the variable capacitor C1, which in turn continuously depends on the air pressure acting on the sensor 1. Thus, we have the opportunity to continuously change the resonant frequency of the sensor 1 on the pressure and / or other physical quantities.

To measure the humidity in the capacitance C1 of the sensor 1, an interelectrode material, dielectric conductivity and / or size, which depend on humidity, can be used, which similarly leads to a change in the capacitance of the capacitor and, as a result, a change in the resonant frequency of the oscillatory circuit of the sensor and allows the measurement of humidity way.

To measure the temperature, a material with a sufficient coefficient of thermal expansion, for example polyethylene, can be used as the interelectrode material of the capacitance C1 of the sensor 1. When exposed to a temperature capacitor, the interelectrode material expands and the capacitance of the capacitor changes, since the distance between the plates changes, which also leads to a change in the resonant frequency of the oscillatory circuit of the sensor 1 and allows temperature measurement by the proposed method.

To measure the temperature, the inductance L1 of the sensor 1 can also be used, which has the ability to change depending on the temperature due to a change in the shape of the conductor constituting the inductance and / or due to changes in the properties of the material in the immediate vicinity of such a conductor, which also allows temperature measurement in the described way. Similarly, other principles of dependence of the capacitance C1 and / or inductance L1 and, accordingly, the resonant frequency of the oscillatory circuit of the sensor 1 on the measured physical quantity can be used. Thus, the passive oscillatory circuit used in the sensor has a new, previously unknown property, namely, the dependence of the resonant frequency of the oscillatory circuit on various physical parameters of at least the following: pressure, temperature, humidity.

When using a system for monitoring tire pressure in automobile tires, the receiving circuit L2 can consist of several turns of conductive material (it can be made, for example, in the form of a flexible element fixed under the wing of a car body).

When measuring the pressure in the tire by such a system, the electromagnetic field generator 3 and the transceiver circuit 2 act by the electromagnetic field on the oscillating circuit of the sensor 1 located in the field of action of such a field, while the frequency is continuously or in steps or by another algorithm changes in a predetermined range corresponding to the pressure measurement range - scanning is performed. In this case, one of the frequencies of this frequency range coincides (located close enough to detect resonance) with the resonant frequency of the oscillatory circuit of the sensor 1. As a result, the energy absorbed and re-emitted from the induced electromagnetic field by the oscillatory circuit of the sensor 1. This leads to a change in the amplitude-phase characteristic of the electromagnetic field , which is perceived by the transceiver circuit 2, is determined by a parametric detector 4, and is fixed by the control and signal processing unit 5 as the response of sensor 1 at a given frequency. The electronic control unit and signal processing 5 is located inside the car. The value of the detected resonant frequency of the sensor circuit 1 judges the pressure in the tire.

The implementation of the proposed system may be different:

- an alternating electromagnetic field is generated by the device by means of two interconnected electromagnetic circuits of the same resonant frequency (according to the principle of metal detectors), one of which is used to register the loop sensor and is external to the loop sensor, and the other is the reference one. Initially, the loops are set to one and the same resonant frequency and work in phase. However, if there is a sensor in the field of the measuring circuit, which is a passive oscillatory circuit, then it, due to the presence of its own resonant frequency, leads to a change in the resonant frequency of the external circuit, which through a special electrical circuit, which is a comparator, leads to the appearance of a beating device at the output. The beat frequency changes with a change in the resonant frequency of the sensor and is a parameter that determines the pressure acting on the sensor (pressure inside the car tire).

- by means of one transceiver circuit 2 (it can be from one to several turns of wire depending on the frequency of generation) and the electromagnetic field generator 3 connected to it. Measurement is carried out by recording changes in the amplitude-phase characteristics of the generated electromagnetic field when the frequency coincides with the resonance the frequency of the oscillatory circuit 3 and the sensor 1 located in such an electromagnetic field and the perceived circuit 2. Thus, in this measurement method, A single radiating circuit is used, which, at the same time, is used as a receiving circuit. To record the amplitude-phase characteristics, the method of direct detection of the signal voltage on circuit 2 is used;

- in the above system, instead of one transceiver circuit, two circuits can be used, one of which is used to create an electromagnetic field, and the other to register the electromagnetic radiation of sensor 1. An arbitrary combination of such transmitting, receiving, or transceiving circuits can be used, including , in order to increase accuracy, range, reduce energy consumption, work with sensors in different orientations;

- other methods can also be used to determine the resonant frequency of such a circuit of the sensor 1 using external electromagnetic radiation;

- can be used in various frequency ranges of the electromagnetic field, waveforms and scanning algorithms known from the prior art.

Due to the fact that the sensitive element of the pressure sensor 1 is also an element of the oscillatory circuit itself, the design of the sensor is simple, contains a minimum of elements (inductance and variable capacitance), and there is no need to use batteries on the sensor itself to operate, unlike reviewed analogues and prototype. The sensor can be placed in a cap screwed onto the wheels instead of the usual caps, or made by spraying inductance and variable capacitance on a flexible base, for example, a self-adhesive polymer film similar to that used in anti-theft systems in supermarkets (so-called RFID tags), and glued onto inner surface tires or be made in the form of a contour around the perimeter of the wheel. Other sensor designs may also be used to implement the described measurement method. It is possible to combine several sensors in one sensor and / or to share several such sensors.

The control and signal processing unit 5, in addition to the ones described above, can perform the functions of presenting the current value of the measured physical quantity, storing historical values and signaling that maximum values have been reached, both for a person and in the form of an information interface for other devices.

Claims

Claim

1. The system of remote measurement and control of physical quantities, containing at least one sensor, which is a passive oscillatory circuit, consisting of an inductance and a capacitor connected in parallel with it, characterized in that the value of the capacitance and / or inductance has the ability to vary depending on measured physical quantities, changing the resonant frequency of the sensor, an electromagnetic field generator is introduced into the system onto an oscillating circuit, a parametric resonance detector, and a control and processing unit and signals, while the inductance and capacitance of the circuit are designed so that the resonant frequency of the sensor corresponds to the selected range of the system.

2. The system according to claim 1, characterized in that the capacitance has the ability to change due to changes in the interelectrode space and / or due to changes in the properties of the dielectric from the measured physical quantity.

3. The system according to claim 2, characterized in that the capacitance is made in the form of movable conductive plates separated by air space or other elasto-plastic dielectric material that changes shape or size depending on the measured physical quantity.

4. The system according to claim 2, characterized in that a material with a dielectric conductivity depending on the measured physical quantity is used as the dielectric of the capacitance.

5. The system according to claim 1, characterized in that the inductance has the ability to change due to a change in the shape of the conductor constituting the inductance and / or due to a change in the properties of materials in the immediate vicinity of such a conductor.

6. The system according to claim 1, characterized in that the electromagnetic field and the transceiver circuit galvanically connected to the electromagnetic field generator and a parametric detector are used as a connection with the sensor.

7. The system according to claim 1, characterized in that two circuits are used as communication with the sensor, one of which is receiving, the other transmitting or an arbitrary combination of such receiving, transmitting and receiving-transmitting circuits.

8. The method of remote measurement and control of physical quantities, which consists in determining the value of the measured physical quantity from the value

SUBSTITUTE SHEET (RULE 26) the resonant frequency of the sensor, which depends on the parameter of the measured physical quantity, which is determined by creating a variable electromagnetic field generator in the zone of the sensor’s location _> whose frequency is changed by changing the frequency of the generator in a given range, while using a parametric detector that records the change in amplitude-phase characteristics the electromagnetic field, determine the coincidence of the frequency of the electromagnetic field of the generator with the resonant frequency of the sensor, according to the detected resonance At the current frequency, the current value of the measured physical quantity is judged.

SUBSTITUTE SHEET (RULE 26)