DE202021105263U1 - bending angle sensor - Google Patents

Abstract

The bending angle sensor includes a sensor element with electrodes connected to a polymer; a transducer configured such that a change in geometry of the polymer causes an electrical change in the transducer; a readout module capable of detecting an electrical change and characterized in that a sensing element includes two capacitors, each consisting of three elastic layers: two electrodes and an intermediate dielectric, each electrode being made of reactoplast with volume-homogenized carbon nanotubes, the Converter includes a switch, a precision comparator, a microcontroller connected to the switch, the comparator and the clock generator with temperature stabilization of the frequency, there is a low-noise reference voltage source with temperature compensation, and each capacitor of the sensor element is connected to a commutator designed so is that he alternately switches the first and second capacitors with the current source, connecting the capacitors in parallel to the input of the comparator, so there is the possibility of connecting the instantaneous voltage value to the said Comparing capacitors with the voltage of the reference voltage source, the comparator output being connected to the counter registers of the microcontroller, recording of the comparator values independent of the microcontroller software being provided, the readout module being in the form of a headset with the Possibility of transferring measurement results to a computer or mobile device via wireless interface, as well as the possibility of powering the transducer.

Description

The utility model relates to the field of metrology, namely: it belongs to measuring devices - sensors that can be used in various fields of technology where extremely precise spatial measurement of bending angles is required or where the technology of virtual reality is used. The sensors can be used in devices to regenerate fine motor skills in the event of motor disorders and to control the rehabilitation process.

• - ein von einer Person getragenes Kleidungsstück;
• - einen elektromagnetischen Energiestrahler;
• - einen elektromagnetischen Energieempfänger;
• - eine spiralförmige Leitung zum Transport elektromagnetischer Energie, in dem elektromagnetische Energie vom elektromagnetischen Energiestrahler zum elektromagnetischen Energieempfänger durch die Leitung fließt, die so konfiguriert ist, dass das menschliche Körpergelenk bedeckt wird. Das Strecken oder Biegen des Leitungselements führt zur Änderung eines oder einiger Parameter elektromagnetischen Energieflusses;
• - und einen Datenprozessor, der Änderungen in einem oder mehreren Parametern analysiert, damit die Bewegung eines Körpergelenks gemessen wird.

A well-known analogue is a sensor for measuring the bending angle, part of intelligent clothing for ambulatory registration of human movements, - US20160338644 , 09/17/2013, containing:

• - a garment worn by a person;
• - an electromagnetic energy emitter;
• - an electromagnetic energy receiver;
• - a helical electromagnetic energy transport conduit in which electromagnetic energy flows from the electromagnetic energy emitter to the electromagnetic energy receiver through the conduit configured to cover the human body joint. The stretching or bending of the conducting element results in a change in one or some parameters of electromagnetic energy flow;
• - and a data processor that analyzes changes in one or more parameters to measure movement of a body joint.

The disadvantage of the analog is the complexity of its structure, namely, it is necessary to use a spiral line to transport electromagnetic energy, which ultimately reduces the accuracy of motion measurement.

• - ein Sensorelement in Form von zwei Elektroden, die mit einem Polymer verbunden sind,
• - einen Wandler, der so konfiguriert ist, dass eine Änderung der Polymergeometrie zur elektrischen Änderung im Wandler führt,
• - und eine Ableseelektronik, die mit dem Sensorelement und dem Wandler verbunden und fähig ist, eine elektrische Änderung zu erkennen.

A well-known analog bending angle sensor - US6809462 , 04/05/2000, serving as a prototype

• - a sensor element in the form of two electrodes connected to a polymer,
• - a transducer configured in such a way that a change in polymer geometry results in an electrical change in the transducer,
• - and reading electronics connected to the sensor element and the transducer and capable of detecting an electrical change.

The disadvantage of the analogue is a low sensitivity of the sensor, as well as low accuracy when measuring bending angles.

The technical result of the proposed utility model is - compared to analogues - increased sensitivity of the sensor, which ensures high accuracy of measuring the bending angle and the possibility of using the sensor to work with a virtual environment.

• zeigt den Aufbau des Biegewinkelsensors.
• zeigt den Kondensator des Biegewinkelsensors.
• zeigt die Kondensatoren des Beugewinkelsensors an der Hand eines Patienten.

The technical result is achieved in the bending angle sensor, which contains a sensor element with electrodes connected to a polymer; a transducer configured such that a change in polymer geometry causes an electrical change in the transducer; a readout module capable of detecting an electrical change; a sensor element contains two capacitors, each consisting of three elastic layers: two electrodes and a dielectric in between. Each electrode is made of reactoplast with volume-homogenized carbon nanotubes, the transducer contains a switch, a precision comparator, a microcontroller connected to the switch, the comparator and the clock generator with temperature stabilization of the frequency, a low-noise reference voltage source with temperature compensation is provided. Each capacitor of the sensor element is connected to a commutator arranged to alternately switch between the first and second capacitors and the power source. The capacitors are connected in parallel to the input of the comparator, so that it is possible to compare the instantaneous voltage value on said capacitors with the voltage of the reference voltage source. The comparator output is connected to the counter registers of the microcontroller, the comparator values being recorded independently of the microcontroller software. The reading module in the form of a headset is designed with the possibility of transferring measurement results to a computer or mobile device via a wireless interface, as well as the possibility of powering the transducer.

• shows the structure of the bending angle sensor.
• shows the capacitor of the bending angle sensor.
• shows the capacitors of the flexion angle sensor on a patient's hand.

the inside The bending angle sensor shown contains a sensor element 1 with electrodes 2 which are connected to the polymer 3, as in FIG shown a converter 4, which in the scheme of shown and configured so that a change in geometry of the polymer 3 causes an electrical change in the transducer 4, a readout module 5 configured to detect an electrical change. The sensor element 1 contains two capacitors 6,7, each consisting of three elastic layers: two electrodes 2 and the dielectric 8 lying between them, as in shown, each electrode 2 is made of reactoplast with carbon nanotubes 9 homogenized in volume, the converter 4 contains a commutator 10, a precision comparator 11, a microcontroller 12, which is connected to the converter 10, the comparator 11 and the clock generator 13 with temperature stabilization associated with the frequency. A low-noise reference voltage source 14 with temperature compensation is present. Each capacitor 6 and 7 of the sensor element 1 is connected to a commutator 10 designed to alternately switch the first 6 and second 7 capacitors with the power source 15 . The capacitors 6, 7 are connected in parallel to the input of the comparator 11, so that it is possible to compare the instantaneous voltage value across the capacitors 6, 7 with the voltage of the reference voltage source 14. The output of the comparator 11 is connected to the counter registers 16 of the microcontroller 12, which makes it possible to register the values of the comparator 11 independently of the software of the microcontroller 12. The reading module 5 in the form of a headset is designed in such a way that it can transmit the measurement results to a computer or a mobile device via a wireless interface and can supply the converter 4 with power.

Let's take an example of a concrete implementation of the bending angle sensor. The sensor is used in medicine as part of a hand movement monitoring device for the fine motor rehabilitation process. The sensor is used to measure wrist flexion angles. The capacitors 6, 7 are in the form of elastic plates sewn into the elastic fabric 17, as in Fig shown. Capacitors 6, 7 are located on each phalange, capacitor 6 - below, capacitor 7 - above. The converter 4 is located on the inside of the palm and is connected to the capacitors by means of conductors. The power source 15 in the form of an accumulator is located on the outside of the palm and is connected to the converter by means of conductors. The elements are connected using an elastic fabric 17 resembling a glove, which makes it possible to place all the elements of the sensor on the hand.

Each electrode 2 of the capacitor 5, 6 is made using reactoplast technology - the components are mixed by a chemical reaction. The mixing ratio is determined based on the required strength/hardness of the end product, the reaction takes place under normal ambient conditions. A high-speed mixer and a special agitator are used to homogenize the carbon nanotubes 8 . After that, according to the principle of the baking process, each layer is applied in layers - conductor layer (electrode 2), then dielectric (insulator 8), as in shown, then the next conductor layer. A squeegee printing machine is used for this. The construction of the electrode 2 described ensures that it is elastic and at the same time serves as a conductor. As a result, a high level of accuracy is achieved when measuring the change in the electrical capacitance of the capacitors 6, 7, which occurs as a result of the bending of the fingers.

In order to ensure higher sensitivity of the sensor, a low-noise voltage source ADR4525 is used as the reference voltage source 14, the output voltage error of which is ±0.02%, temperature coefficient - 1 ppm/°C, output noise range - IµV (0.1-10Hz). As a comparator 11, the precision comparator LMP7300 is used, which has the following characteristics: delay of formation of the output signal - 4 µs, offset voltage - 0.3 mV, accuracy of the reference voltage - 0.25%, common mode noise rejection coefficient - 100 dB. A temperature-compensated quartz oscillator FOX924B-20.000 with a basic frequency setting error of ±1.5 ppm is used as clock generator 13 with temperature stabilization.

In order to achieve a high signal processing speed and thereby ensure a high sensitivity of the sensor, the output of the comparator 11 is connected directly to the counter registers 16 of the microcontroller 12, so that the values of the comparator 11 can be recorded independently of the software of the microcontroller 1. The outputs of the comparator 11 are connected to the respective inputs of the timers of the microcontroller 12, which are configured in such a way that when the signal from the comparator 11 changes, the timer logic circuit is triggered, which detects the current value of the timer counter register and this value saves in the acquisition register under formation of the sign "timer acquisition". The process of timer value acquisition described is performed by fixed logic of the timer without the involvement of signals from the microcontroller 12, and for the capacitance measurement, the acquisition time may be disregarded. Reading and processing of the results from the capture register 16 occurs in the microcontroller 12 program loop when the value of the "timer capture" attribute is true. The transducer elements are placed on the common pressure plate of the transducer 4.

The reading module 5 in the form of a headset is connected to the converter by means of a conductor. It is designed to transmit measurement results to a computer or mobile device via wireless interface, which eliminates the need for additional devices near the sensor, reduces interference from these devices on the sensor, and provides the required accuracy when measuring bend angles is guaranteed.

Let's consider an application example of the bend angle sensor. The sensor described here has several sensor elements 1. They are designed to measure the flexion angle of the finger joints of a patient: two sensor elements 1 per finger from the index finger to the little finger (two joints on each finger), one sensor element 1 at the thumb joint. The high-precision flexion angle sensor solves the problem of measuring and reading the limb flexion in a patient in fine motor rehabilitation. When reading, the sensor, thanks to its small size, does not disturb the patient while he/she performs a series of exercises to regenerate lost motor function.

The patient flexes the finger. As a result, the sensor element 1 is bent so that the dielectric 8 of the capacitor 7, as in shown, thinned and the dielectric 8 of the capacitor 6 is thickened. This leads to a corresponding increase in the capacitance of the capacitor 7 and a reduction in the capacitance of the capacitor 7 compared to the quiescent state. The microcontroller 12 generates a measuring cycle: the charging of the capacitors 6, 7 of the sensor element 1 and the clocking of the register counter 16 by the oscillator 13 are started synchronously. The commutator 10 switches the capacitors 6, 7 for charging by the current source 15 according to the signal from the microcontroller 12. In parallel, the comparator 11 compares the instantaneous voltage value on the displayed capacitors 6, 7 with the voltage of the reference voltage source 14. The fixing of values of the Counter register 16 is done by hardware after the trigger signal of the comparator 11, which increases the sensitivity of the sensor compared to analogues. The result is the difference in the number of pulses in the counter register 16 per measurement cycle. The value of the bending angle is calculated by the microcontroller according to the set function of the dependence of the bending angle on the difference in the number of pulses. With the help of the reading module 5 in the form of a headset 5, the query of the converter 4 and the transmission of measurement results via a wireless interface to a computer or a mobile device are implemented

wo

• α - Messwert, °,
• UkSe - Umsetzungskoeffizient des Sensorelements, [°/PF],
• UkMw - Umsetzungskoeffizient des Messwandlers, [PF/(Imp.)],
• N0 - Nullpunktversatz,
• N - Impulsanzahl gleich der Differenz der Zählerregister 16 sind.

The conversion of codes into degrees, the compensation of the initial bias is carried out according to the formula: $$\mathrm{a}=\text{UkSe}*\text{UkMw}*\left(\text{N}-\text{N}0\right),$$

Where

• α - reading, °,
• UkSe - conversion coefficient of the sensor element, [°/PF],
• UkMw - conversion coefficient of the instrument transformer, [PF/(Imp.)],
• N0 - zero offset,
• N - number of pulses are equal to the difference between the counter registers 16.

Thanks to the high sensitivity of the sensor, the data from the sensor is well synchronized with the virtual reality image of the hand and this gives the possibility to control the image using a bending angle sensor.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US20160338644 [0002]
• US6809462 [0004]

Claims (1)

The bending angle sensor includes a sensor element with electrodes connected to a polymer; a transducer configured such that a change in geometry of the polymer causes an electrical change in the transducer; a readout module capable of detecting an electrical change and characterized in that a sensing element includes two capacitors, each consisting of three elastic layers: two electrodes and an intermediate dielectric, each electrode being made of reactoplast with volume-homogenized carbon nanotubes, the Converter includes a switch, a precision comparator, a microcontroller connected to the switch, the comparator and the clock generator with temperature stabilization of the frequency, there is a low-noise reference voltage source with temperature compensation, and each capacitor of the sensor element is connected to a commutator designed so is that he alternately switches the first and second capacitors with the current source, connecting the capacitors in parallel to the input of the comparator, so there is the possibility of connecting the instantaneous voltage value to the said To compare capacitors with the voltage of the reference voltage source, the comparator output is connected to the counter registers of the microcontroller, recording of the comparator values independent of the microcontroller software is provided, the reading module is in the form of a headset with the possibility of transmitting measurement results to a computer or mobile device via wireless interface and with the possibility of powering the transducer.

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