WO2022189142A1 - Interface tactile permettant une mesure d'une intensité d'une force d'appui. - Google Patents
Interface tactile permettant une mesure d'une intensité d'une force d'appui. Download PDFInfo
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- WO2022189142A1 WO2022189142A1 PCT/EP2022/054421 EP2022054421W WO2022189142A1 WO 2022189142 A1 WO2022189142 A1 WO 2022189142A1 EP 2022054421 W EP2022054421 W EP 2022054421W WO 2022189142 A1 WO2022189142 A1 WO 2022189142A1
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- plate
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- force
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- transducer
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Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/016—Input arrangements with force or tactile feedback as computer generated output to the user
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
- G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
- G06F3/03547—Touch pads, in which fingers can move on a surface
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0414—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position
- G06F3/04142—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position the force sensing means being located peripherally, e.g. disposed at the corners or at the side of a touch sensing plate
Definitions
- the invention is a user interface configured to measure a bearing force exerted by an external body touching the contact surface of the interface.
- touch interfaces A large number of devices marketed today are controlled by touch interfaces. This type of interface generally includes a touch surface, which allows simple and interactive control of the device.
- the device can be a mobile phone, household appliance, car equipment, or a professional tool.
- touch screens include sensors allowing detection of the contact of a finger by capacitive effect.
- these screens have a contact surface, capacitively coupled to a transparent conductive mesh. This makes it possible to locate an area of the screen touched by a user's finger.
- the localization of the contact is sufficiently powerful to make it possible to control a device by the position of the finger or by a trajectory of the finger along the screen, or even by dynamic parameters of movement of the finger, such as a speed or an acceleration .
- capacitive detection is efficient for locating a contact of a finger on the contact surface of a screen, it does not make it possible to quantify the force exerted by the finger.
- Touch detection is an all-or-nothing type detection, and only determines finger contact or no contact.
- Patent US10860107 describes a tactile interface and a method making it possible to estimate an intensity of a pressing force exerted on a vibrating tactile interface.
- the touch interface comprises a rigid plate, the latter being vibrated by actuation transducers.
- the actuation transducers are parameterized to generate a vibration of the plate according to a setpoint amplitude whose level is predetermined.
- the pressing of a finger on the plate causes a variation of the vibration amplitude with respect to the setpoint amplitude, which makes it possible to detect the pressing and to quantify the force exerted by the pressing on the plate.
- the inventors have found that the approach described in this patent is reliable. However, some applications require a large measurement dynamic, that is to say an extended measurement range.
- a first object of the invention is an interface comprising:
- At least one actuation transducer configured to vibrate the plate according to an activation signal
- At least one detector configured to detect an amplitude of a vibration of the plate and to generate a detection signal, the detection signal oscillating according to an amplitude of oscillation depending on the amplitude of vibration detected;
- an amplification circuit extending between an input and an output, the input being connected to the detector and the output being connected to the actuation transducer; the interface being characterized in that:
- the amplification circuit is configured to be powered by an input signal, the input signal being an oscillating signal established from the detection signal;
- the amplification circuit comprises an amplifier, configured to amplify the input signal, by applying an amplification gain to it, so as to send an output signal to the actuation transducer, the output signal corresponding to the signal d the amplified input, the output signal forming the activation signal of the actuation transducer;
- the interface comprises a processing unit, powered by a processing signal, the processing signal depending on the input signal or on the detection signal, the processing unit being configured for:
- the amplification gain is non-linearly dependent on the input signal.
- the plate and the feedback loop can form a self-sustaining oscillator.
- the reference signal corresponds to the processing signal in the absence of force exerted on the plate by the external body.
- the processing signal can be established from:
- the characteristic quantity quantifying the amplitude of oscillation of the input signal
- the processing signal can be established from:
- the characteristic quantity quantifying the amplitude of oscillation of the detection signal
- the amplification gain depends on a characteristic quantity of the input signal, the characteristic quantity quantifying the amplitude of oscillation of the input signal.
- the amplification gain may decrease depending on the characteristic magnitude of the input signal.
- the amplification gain may comprise a maximum gain weighted by a moderation term, such that the amplification gain is all the lower as the characteristic magnitude of the input signal is high.
- the amplification gain can be maximum when the characteristic magnitude of the input signal reaches a predetermined minimum value.
- the amplification gain can be minimal when the characteristic quantity of the input signal reaches a value greater than or equal to a threshold value.
- a screen is attached to the plate, all or part of the plate being transparent.
- the plate may have a resonant vibration frequency between 20 kHz and 200 kHz.
- At least one actuation transducer may be a piezoelectric transducer.
- At least one detector can be a piezoelectric transducer.
- the interface may comprise a control unit, the control unit being configured to send a control signal to a device, connected to the interface, as a function of the force signal.
- the interface may include a location circuit, configured to determine a position of a point of contact between the outer body and the plate.
- the interface may include a filter, arranged between the detector and the amplification circuit, the filter being configured to define a frequency bandwidth of the input signal sent to the amplification circuit. Thus, the input signal is obtained from a filtering of the detection signal.
- the plate is connected to at least one auxiliary transducer separate from an actuation transducer, the auxiliary transducer being connected to an auxiliary power supply, the auxiliary transducer being configured to set the plate into vibration, according to a set vibration amplitude, predetermined, and according to an ultrasonic vibration frequency, so as to produce a haptic feedback effect;
- the interface is configured to activate the auxiliary transducer, or each auxiliary transducer, when the force signal crosses a predetermined threshold.
- an actuation transducer is connected to a switch, the switch being configured to:
- the actuation transducer then being configured to set the plate in vibration, according to an amplitude setpoint vibration, predetermined, and according to an ultrasonic vibration frequency, so as to produce a haptic feedback effect.
- a second object of the invention is a method for estimating a force exerted on a plate of an interface according to the first object of the invention, the method comprising: a) application of an external body on the plate, by exerting a force on the plate; b) using the processing unit, estimation of an intensity of the force exerted by the external body on the plate.
- a third object of the invention is a method for controlling a device, using an interface according to the first object of the invention, the device being parameterized by at least one operating parameter, the method comprising :
- the interface can in particular be a tactile interface.
- the outer body can be a finger or a stylus.
- Figures IA to 1E represent a first embodiment of a touch interface.
- FIG. 2A schematizes the main steps of a method for estimating an intensity of a force by implementing an interface according to the invention.
- Figure 2B illustrates the establishment of a sustained self-oscillation regime on a plate coupled to a feedback loop.
- Figure 2C is a detail of Figure 2B.
- Figure 2D has an upper part and a lower part.
- the upper part 2D sup represents the temporal evolution, of Gaussian form, of a bearing force applied to the interface (in Newton N).
- the lower 2D part shows different force signals, generated by a tactile interface according to the invention (ordinate axis), as a function of time (abscissa axis), for different intensities of force applied, following the time evolution plotted in the figure 2D sup .
- Each force signal is representative of the intensity of an applied force as a function of time.
- FIG. 2E shows an evolution of an amplification gain moderation term as a function of the effective value of the input signal of the amplification circuit.
- FIG. 2F schematizes the attenuation of the vibration of a plate, as a function of the vibration amplitude, in the case of a linear behavior (curve a) and a nonlinear behavior (curve b).
- FIGS. 3A schematizes an interface used to carry out experimental tests.
- Figure 3B shows different intensities of force applied to the interface, as a function of time, during the experimental tests.
- Figures 3C, 3D and 3E show different processing signals depending on the intensity of the applied force.
- the processing signals are respectively the effective amplitude of the input signal (Fig. 3C), the amplification gain (Fig. 3D) and the frequency of the input signal (Fig. 3E).
- FIG. 3F represents various force signals measured as a function of force intensities applied to the interface. Each point in the figure corresponds to a force intensity-force signal couple.
- the force signals have been determined by taking into account three different amplification gains, parameterized by a parameter n. We also have shown force signals obtained by implementing a configuration of the prior art.
- Figure 3G shows fitting curves of the point clouds of Figure 3F taking into account an exponential fitting function.
- FIGS. 4A and 4B represent a second embodiment of a touch interface, in which the touch interface comprises a capacitive screen.
- FIGS. 4C and 4D illustrate examples of implementation of the touch interface described in connection with FIGS. 4A and 4B.
- FIG. 5A diagrams an embodiment of an interface comprising actuation transducers making it possible to induce haptic feedback from the interface.
- Figure 5B is a variant of the embodiment described in connection with Figure 5A.
- FIGS IA to 1E represent an example of interface 1 according to the invention.
- the interface comprises a plate 10 intended to be touched by an external body 9.
- the external body 9 is a finger, which corresponds to most of the applications envisaged.
- the outer body 9 can be a stylus, or any other means allowing to act on the plate 10.
- the interface is connected to a device 50.
- the device 50 can be, in a non-limiting manner, a communication device, a computer device, a machine, household electrical equipment, a dashboard of a vehicle. Operation of apparatus 50 is governed by at least one operating parameter.
- the touch interface 1 is intended for setting a value of the operating parameter of the device 50.
- the plate 10 includes an adjustment zone 10', intended for adjusting the parameter under the effect of a pressure exerted by the finger 9. According to different application possibilities:
- the interface can bring up an interactive menu or a virtual setting button
- a virtual button of the interface becomes operable, so as to be able to adjust a parameter
- the interface can generate haptic feedback, for example a click effect.
- the value of the parameter is gradually increased when the finger presses on the plate, in the adjustment zone.
- the device is by example a multimedia system of a vehicle.
- the parameter can for example be the sound volume of the multimedia system. The more you press, the higher the sound volume.
- Plate 10 is rigid. It extends between an outer face 10 and an inner face 10,.
- the outer face 10 e forms a contact surface intended to be touched by the finger 9.
- the inner face 10 i and the outer face 10 e preferably extend parallel to each other.
- the distance between the outer face 10 e and the inner face 10 defines a thickness e of the plate.
- the thickness e of the plate is sized to allow vibration of the plate 10, preferably according to an ultrasonic vibration frequency.
- the thickness e of the plate 10 is preferably less than 10 mm, or even less than 5 mm.
- the thickness e is adjusted according to the nature of the material and its mechanical properties (rigidity, solidity). It is for example between 1 and 5 mm for glass or a material such as Plexiglas.
- the inner face 10 and the outer face 10 e are flat, which corresponds to the simplest configuration to manufacture.
- the plate extends, parallel to a lateral axis X, along a width l and, parallel to a longitudinal axis Y, along a length L.
- the length L and the width l can be between 5 cm and a few tens of cm, for example 30 cm, or even more.
- the lateral axis X and the longitudinal axis Y define a main plane P XY .
- the internal face 10, and/or the external face 10 e can be curved.
- the surface of the plate 10 is preferably greater than 1 cm 2 , or even 10 cm 2 or 50 cm 2 .
- the plate 10 is formed from a rigid material, such as glass, or a polymer, or wood, or a metal, or a semiconductor, for example silicon.
- the plate 10 can be transparent or opaque.
- the plate 10 can comprise opaque parts and transparent parts.
- the plate 10 is delimited, along the lateral axis X, by a first lateral border 10i and a second lateral border IO2.
- the plate is intended to be vibrated, in particular according to a spontaneous, self-sustaining vibration as described below.
- spontaneous vibration is meant a vibration which is not initially specified as a function of an instruction sent to the actuation system, in particular an amplitude and/or frequency instruction.
- the plate 10 is connected to one or more detectors 11.
- By “in the vicinity”, is meant at a distance preferably less than 2 cm.
- each detector 11 is a piezoelectric transducer used as a sensor.
- Each detector 11 has no driving action on the plate 10, but allows detection of the vibration amplitude of the plate according to a sampling frequency.
- the sampling frequency is for example equal to a few kHz, a few tens of kHz, or a few hundreds of kHz.
- one or more actuation transducers 12 are connected to the plate 10.
- Actuation transducers 12 are configured to be activated by an electrical activation signal. Under the effect of the activation signal, the actuation transducers exert pressure on the plate 10 so as to produce a local deformation of the plate, for example in a direction perpendicular to the plate.
- the activation signal is periodic
- the deformation of the plate 10 is periodic, which leads to the formation of a vibration 19.
- the vibration can for example be generated by a bending wave forming through the plate.
- the bending wave can be stationary or progressive. According to other possibilities, the vibration can be a wave other than a bending wave, for example a compression wave.
- An example of vibration 19 is schematized in FIGS. 1C and 1D.
- the arrangement of the detectors 11 and the actuating transducers 12 at the edge of the plate 10 does not constitute a necessary condition: the detectors or the transducers can be arranged according to other configurations, for example in the form of a line, at the middle of the plate, or of a matrix, or at positions advantageously chosen as vibration antinodes in the case of a standing wave.
- the position of the antinodes can be determined by simulation or by prior experimental characterization.
- Each detector 11 and/or each actuation transducer 12 can be a transducer of the piezoelectric type, comprising a piezoelectric material, for example AIN, ZnO or PZT, arranged between two electrodes. It may for example be the reference PZT 406.
- the detectors 11 or the actuating transducers 12 may be such that the piezoelectric material is deposited, in the form of one or more thin layers, between bias electrodes.
- a detector or an actuation transducer can be an electromechanical resonator, for example of the MEMS type (Micro ElectroMechanical System - electromechanical microresonator), or of the electrostrictive or magnetostrictive type.
- MEMS Micro ElectroMechanical System - electromechanical microresonator
- electrostrictive or magnetostrictive type for example of the MEMS type (Micro ElectroMechanical System - electromechanical microresonator), or of the electrostrictive or magnetostrictive type.
- the interface 1 comprises an electronic amplification circuit 20, connected to at least one detector 11 and to an actuation transducer 12.
- the function of the electronic amplification circuit is described in connection with Figures IB to 1E.
- the electronic amplification circuit 20 is placed under the plate 10.
- the touch interface 1 comprises a processing unit 30, intended to estimate a pressing force exerted by the external body 9 on the plate 10.
- the function of the processing unit 30 is described in connection with FIGS. IB to 1E .
- the touch interface 1 comprises a control unit 40, intended to control the device 50 controlled by the interface.
- the control unit 40 transmits the value of the operating parameter, resulting from the action of the finger 9 on the plate, to the device 50.
- the control unit 40 may include a microprocessor, so as to to be able to establish a control signal according to a level of force resulting from the processing unit 30.
- FIG. IB shows a sectional view of the touch interface.
- the amplification circuit 20 extends between an input 21 and an output 22.
- the input of the amplification circuit is connected to at least one detector 11.
- the output 22 of the amplification circuit is connected to at least one transducer 12.
- the amplification circuit 20 comprises an amplifier 23, intended to amplify the input signal V in (t), delivered by the detector 11 at a time t, so as to establish an output signal V out (t + dt), at a later time t + dt, such that:
- V out (t + dt) g(t)V in (t) (1)
- g(t) corresponds to an amplification gain
- dt depends on the sampling frequency. More precisely, dt is the inverse of the sampling frequency.
- the output signal V out (t+dt) resulting from the amplification circuit 20 forms an activation signal for the actuation transducer 12 at the instant t+dt.
- the amplification gain g(t) is for example such that: where: is the amplification gain; - G is a gain called "critical gain", - a is a positive real strictly greater than 1, allowing adjustment of the value of a maximum gain Ga, the maximum gain being positive. - n is a strictly positive real; is a positive characteristic quantity of V in (t). is for example a estimate of the effective value (RMS) of Vi n (t), or an estimate of the amplitude of oscillation of V in (t). Can be calculated from V in (t) taking into account one period or several periods, for example between 10 and 100 periods.
- the signals V in and V out are alternating signals (ie oscillating), due to the vibration of the plate, the magnitudes V in (t) and V out (t) correspond to instantaneous signals at each instant t.
- the input signal V in is formed from a detection signal V d , resulting from a detector 11.
- the input signal V in is established from the detection signal V d . It may for example be a filtered detection signal, as described below.
- the parameters ⁇ and n make it possible to adjust the response of the force measurement system, a response explained later in connection with FIGS. 3F and 3G.
- the maximum gain is reached when reaching a predetermined value, in this example equal to
- the amplification gain decreases, and tends towards a minimum value which is here equal to 0.
- the amplification gain g(t) is a decreasing function of
- An important aspect of the invention is that the (or each) detector 11, the amplification circuit
- the plate 10 and the feedback loop behave then like a self-sustaining oscillator: the oscillation is maintained according to an amplitude which stabilizes.
- the amplification circuit 20 The energy losses, at the level of the plate (attenuation of vibrations), or of the plate/detector or plate/transducer interfaces are compensated by the amplification circuit 20, the latter being powered by an external power supply. It is noted that unlike the interface described in the prior art, the plate does not vibrate according to a predetermined setpoint amplitude or frequency. When it comes to measuring an intensity of a force, the actuation transducer of the plate is not controlled so as to put the plate into vibration according to a set amplitude or frequency. The plate vibrates at a spontaneous amplitude, resulting from the self-sustained oscillation by the oscillator formed by the plate and the feedback loop.
- the plate has vibration modes (frequencies and resonance amplitude) that are specific to it.
- the plate spontaneously enters into vibration according to a resonance frequency, depending on the material, the dimensions of the plate, the position of the (or of each) actuation transducer 12 and of each detector 11, as well as of the electrical circuits forming the loop of feedback.
- the resonant frequency of the plate be ultrasonic. This makes vibration inaudible to a user touching the interface or plate.
- the resonance frequency is preferably between 20 kHz and 200 kHz.
- the plate can come into vibration by triggering one or more actuating transducers 12.
- a brief trigger signal for example sinusoidal, is sent so as to initiate the vibration. The latter is then self-sustaining due to the action of the feedback loop.
- the trigger signal can be produced by the amplification circuit 20.
- the frequency of the trigger signal is preferably defined beforehand, on the basis of a modeling or an a priori as to the frequency of the oscillations of the plaque.
- the oscillation frequency can be imposed.
- the value of the critical gain G can be determined on the basis of experience feedback or tests. It corresponds to the value from which the signal V in (t) is of constant amplitude and stabilized over a window of time, using a constant amplification gain g lin (ie independent of V in (t)), as described in connection with expression (2').
- g lin independent of V in (t)
- G can be the minimum value of g lin from which the system, implementing the linear amplification gain g lin , is oscillating.
- the value of the critical gain G can be determined, using the linear relation explained in (2'), so that the system formed by the plate and the feedback loop behaves like an oscillator : the amplitude of the signal V in (t) reaches a non-zero, constant and stabilized value over a time window.
- This critical gain value G can then be used in the boost gain g(t) described in (2).
- the parameter ⁇ corresponds to a multiplicative factor, such that the maximum gain G ⁇ is sufficiently greater than the critical gain G so that the system is always oscillating.
- the parameter ⁇ can for example be between 1 and 10.
- the term is a moderation term, allowing to adjust the amplification gain g(t) as a function of the value of .
- the term moderation is generally between 0 and 1. It is all the lower as the value of is high.
- self-sustaining oscillation an oscillation whose amplitude, in the absence of external disturbance, is stable, or considered as such, within statistical fluctuations.
- FIG. 2C An example of self-sustaining oscillation is illustrated in FIG. 2C described later.
- the amplification gain g(t) comprises the maximum gain Ga, which induces the oscillation, as well as the moderation term which makes it possible to obtain a stable oscillation in the time.
- Amplification gains exhibiting analytical forms different from that explained in expression (2) are possible. It is for example possible to use another amplification gain g(t), preferably non-linear with respect to .
- the amplification gain g(t) comprises a positive amplification term, in this case the maximum gain G ⁇ and a nonlinear moderation term with respect to and decreasing according to This makes it possible to obtain a self-sustained oscillation, that is to say an oscillation of stable amplitude over time, in the absence of stress exerted on the plate.
- the processing unit 30 comprises an input 31 and an output 32.
- the unit processing is supplied by a processing signal S proc (t).
- the processing signal addressed to the processing unit depends on the input signal V in (t), or on the detection signal V d (t).
- the processing signal S proc (t) is a quantity characteristic of the input signal V in (t), the quantity characteristic being for example the effective value:
- the processing signal S proc (t) can also be a characteristic quantity of the output signal V out (t+dt), the latter corresponding to the amplified input signal.
- the processing signal S proc (t) can also be the amplification gain g(t).
- the processing signal S proc (f) can also be a frequency of the input signal.
- the processing signal S proc (t) is determined from V in (t), and for example from a quantity characteristic of V in (t). We use the fact that is generally a function monotonous of the intensity F of the applied force. According to one possibility, S proc (t) depends on the frequency of V in (t). The fact that the frequency of V in (t) can vary, in particular according to a monotonic function, as a function of the intensity F of the applied force is then used.
- the processing unit 30 comprises a comparator 33, allowing a comparison between the processing signal S proc (t) and a reference value S ref .
- the comparison is a ratio.
- could also be a difference.
- the comparator 33 generates a force signal V F , representative of the comparison between S proc (t) and S ref .
- the force signal V F equal or proportional to is representative of the force exerted by the finger 9 on the plate
- the relationship between the force signal V F and the intensity F of the support force is linear.
- Figure IC shows plate 10 in a reference configuration. No force is applied to the plate.
- the amplitude of vibration 19 has been exaggerated.
- the amplitude of the vibration of the plate is a few pm or a few tens of pm, typically between 0.1 pm and 50 pm.
- the triggering of the self-sustained oscillation can be an uncontrolled vibration of the plate, following a movement of the interface 1. It can also be a vibration induced by an electronic noise in the electronic circuits forming the feedback loop. The effect of the electronic noise is then amplified by the amplifier, which leads to an activation of the actuation transducer 12 and to the vibration of the plate.
- the plate gradually and spontaneously reaches a stabilized, self-sustaining reference operating regime, characterized by an amplitude and a vibration frequency.
- the effective value of the signal V in (t) resulting from the detector 11 then reaches a reference value S ref which is stored in the processing unit 30.
- the reference value S ref results from the spontaneous oscillation of the plate in the absence of pressure on the interface by an user. It is not a predetermined value.
- S ref corresponds to the value of S proc (t) in the absence of support exerted on the plate.
- FIG. 1D represents a measurement configuration, in which a finger 9 presses on the plate 10.
- the pressing force exerted by the finger results in an attenuation of the amplitude vibration 19 of the plate 10. This leads to a decrease in the effective value of the signal resulting from the detector 11.
- the contact with the finger modifies the transfer function of the actuation transducer system, plate, sensor. Under the effect of the feedback loop, the oscillator stabilizes at a new operating point. This results in a new effective value corresponding to the oscillator modified by pressing the finger.
- the comparison makes it possible to quantify the intensity of the pressing force exerted by the finger on plaque.
- the plate and the feedback loop form a self-sustaining oscillator.
- the amplification circuit 20 makes it possible to maintain an oscillation measurable by the detector 11.
- the oscillator makes it possible to obtain a measurable value, including for low levels, when the pressure exerted on the plate is high.
- the oscillation, maintained by the amplification circuit 20, allows a measurement of force intensities according to a large dynamic.
- the parameter n makes it possible to adjust the response of the device, so as to favor the dynamics or the measurement sensitivity, as described below, in connection with FIGS. 3F and 3G
- a filter 13 is arranged between the sensor (or each sensor) and the amplification circuit 20. It may in particular be a band-pass filter, so as to define a bandwidth of vibration frequencies acceptable. The use of such a filter makes it possible to avoid the establishment of self-oscillation in frequencies outside the passband of the filter.
- the optional filter 13 is shown in Figures 1C and 1D.
- the input signal V in (t) then corresponds to the filtered detection signal V d (t).
- the processing unit 30 is supplied with the signal V out (t + dt ) resulting from the electronic amplification circuit 20.
- the processing unit 30 performs a comparison between the effective value of dt) and a reference value S ref
- the comparator 33 generates a force signal V F , representative of the comparison between S proc (t+dt) and S ref .
- the force signal V F representative of the force exerted on the plate, is equal or proportional to whatever the embodiment, the reference value S ref can correspond to the processing signal S proc (t) in the absence of force exerted on the plate, while the latter oscillates according to the stable self-oscillation regime .
- FIG. 2A represents the main steps of a method for estimating a force exerted on the plate.
- Step 100 measurement of an instantaneous value of an input signal V in (t) from the signal V d (t) detected by a detector 11 at a time t.
- Step 120 supply of an actuation transducer using the signal V out (t+dt), then repetition of steps 100 to 120.
- the effective value spontaneously reaches a stable reference value V ref , under the effect of the self-sustaining oscillation previously described.
- the reference value V ref can be stored in the processing unit 30.
- the step 110 can assume a calculation of an effective value of the input signal V in (t).
- the gain amplification g(t) can use a characteristic quantity of the input signal V in (t), different from the effective value: it can for example be the amplitude of oscillation of V in (t) or of the absolute value of V in (t).
- FIG. 2B an almost instantaneous establishment of an operating mode in self-sustained oscillation has been shown.
- Figure 2C is a detail of Figure 2B according to a short time range.
- Step 130 formation of the processing signal S proc (t).
- the processing signal S proc (t) is established from V in (t). It can in particular be established from a characteristic quantity of V in (t) or from the frequency of V in (t). He is reminded that the term “characteristic quantity” designates a quantity quantifying the amplitude of the oscillation of a periodic signal.
- the processing signal S proc (t) is the effective value of the input signal. Alternatively, it may be the value maximum.
- the processing signal S proc (t) is established from a characteristic quantity of the output signal V out (t+dt).
- Step 140 Estimation of an intensity of a support force.
- Step 140 is implemented by processing unit 30, which calculates the force signal V F as a function of the characteristic magnitude resulting from step 130 and from S ref .
- the force signal V F is representative of the intensity F of the bearing force exerted on the plate.
- the conversion between V F and F can be obtained by calibration.
- the force signal V F can be established from the effective value of V in (t) (or of V out (t+dt)) or other characteristic quantities (maximum value for example).
- the processing signal S proc (t) is the effective value of the input signal.
- the force signal V F results from a comparison between the signal of processing S proc (t) and the reference signal S ref , the latter being equal to the reference value V ref , which corresponds to the value of in the absence of a force pressing on the plate.
- Step 150 (optional) Determination of a value of an operating parameter of the device 50.
- Step 150 is implemented by control unit 40.
- an operating parameter of device 50 controlled by interface 1
- the operating parameter can be determined within a range of values, with each value being associated with an intensity of the force.
- the operating parameter can also comprise only two possible values, for example 0 in the absence of force and 1 in the presence of a support force whose intensity is greater than a certain threshold.
- Figure 2D sup shows the time evolution of the force applied to the plate.
- FIG. 2D inf shows a temporal evolution of the force signal V F (t) (ordinate axis), the time corresponding to the abscissa axis (unit: seconds). It is observed that the application of a force of increasing intensity results in a reduction in the force signal V F , the minimum value reached being equal to 0.5.
- Figure 2D illustrates the ability of the invention to establish an accurate quantification of an intensity of a tracking force, over a wide range.
- Figure 2E represents a variation of the moderation term (axis of ordinates) as a function of (axis of abscissas - Volts), considering As previously indicated, the moderation term forms a decreasing function of It allows an adjustment of the amplification gain g(t) to the circuit input signal amplification, the gain being all the lower as the input signal is high.
- FIG. 2F schematizes the attenuation of the oscillations induced by the plate, when the latter presents a linear behavior (curve a) and a nonlinear behavior (curve b).
- the attenuation axis of ordinates
- the attenuation has been represented as a function of the amplitude of the oscillations (axis of abscissas).
- the nonlinear amplification of the oscillator can thus be partially or totally induced by the plate.
- the amplifier 20 could implement a linear amplification, the amplification gain g(t) being constant.
- the use of a non-linear and configurable amplification gain is advantageous, because it makes it possible to adjust the response of the system as needed, depending on whether one wishes to favor the dynamics, or the sensitivity or the linearity of the force signal. relative to the intensity of the applied force.
- FIG. 3A schematizes the assembly.
- Plate 10 included eleven piezoelectric transducers, of the Ceramtec PZT406 type. The transducers were regularly distributed along the same edge 10 2 of the plate. Ten transducers functioned as an actuating transducer 12, while a transducer, located at one end of the border, functioned as a detector 11.
- the plate 10 was placed on a balance 2, so as to measure the force applied over time, at a sampling rate of 100 Hertz. 1s supports provided the interface between the plate and the balance. A force was applied locally, at a point preset of the plate.
- the amplification circuit 20 implemented an amplification gain g(t) as explained in expression (2).
- ⁇ 2
- G C 0.15
- a force F(t) of varying intensity over time was applied.
- FIG. 3B represents the temporal evolution of the force applied to the plate during a test.
- the force was applied periodically, for periods of about ls.
- a processing signal S proc (t) was measured, the latter being: either the effective value of V in (t): cf. Figure 3C; or the amplification gain g(t): cf. 3D figure; or the oscillation frequency f(V in ) of V in (t): cf. Figure 3E.
- FIG. 3F represents the force signal V F (axis of ordinates) as a function of the intensity of the force applied (axis of abscissas).
- FIG. 3G represents, for each configuration, an exponential adjustment of the force signal as a function of the intensity of the force applied.
- the force signal corresponded to a ratio of the effective value of the voltage measured at the terminals of the detector, to the effective value of the voltage measured in the absence of support exerted on the plate.
- the results are shown in Figure 3F (curve AA).
- the force signal is such that
- the force signal V F is equal to 1.
- the sensitivity of the force measurement corresponds to a variation of the output signal (i.e. V F ) with respect to a variation of the input signal (i.e. F(t)) .
- This corresponds to the local slope of the curves shown in Figures 3F and 3G.
- Another advantage is to be able to obtain a force signal varying linearly with respect to the intensity of the force applied.
- FIGS. 3F and 3G show that the invention makes it possible to obtain better sensitivity in a wider measurement range than according to the prior art. Indeed, the curves representative of the prior art show a flattening effect occurring earlier, that is to say from lower force intensities than by implementing the invention.
- FIGS. 4A and 4B illustrate another embodiment, according to which an intermediate component 15 extends between the detectors 11, as well as the actuation transducers 12, and the plate 10.
- the intermediate component is a screen 15, allowing an image to be displayed through the plate 10, the latter being transparent.
- the sensors and actuation transducers are not arranged in contact with the plate 10. They are mechanically coupled to the plate 10 via the screen 15. The latter is sufficiently rigid to transmit the vibrations between the plate 10 on the one hand and the actuation transducers 12 and detectors 11 on the other hand.
- FIG. 4C represents an example configuration of the interface, in which the adjustment zone 10' is delimited, on the screen 15, by an outline 15.
- the screen also shows a gauge 15 a , extending between a min minimum value and a max maximum value. The greater the force exerted by the finger on the adjustment zone 10', the closer the shaded zone, inside the gauge, to the maximum level.
- the screen 15 can be equipped with a localization circuit, for example a capacitive circuit, allowing localization of the pressure of the finger on the screen 15, through the plate 10.
- a localization circuit for example a capacitive circuit
- FIG. 4D six adjustment zones of the plate, respectively delimited, on the screen, by contours 15' i, 15' 2 , 15' 3 , 15' 4 , 15's and 15' 6 .
- Each adjustment zone is respectively dedicated to the adjustment of an operating parameter P 1 , P 2 , P 3 , P 4 , P 5 and P 6 .
- control unit 40 establishes a control signal according to a level of force resulting from the processing unit 30, and according to a position of the fulcrum resulting from the circuit of location.
- the plate can be vibrated by auxiliary transducers 14, so as to induce ultrasonic vibration of the plate.
- the auxiliary transducers are powered by a setpoint actuation signal, defining an amplitude and a frequency of vibration.
- the ultrasonic vibration can induce a haptic effect on the finger touching the interface, that is to say a feeling of texture or a feeling of clicking in particular depending on the intensity of the pressing force F detected.
- haptic feedback we mean setting the plate into vibration, according to a predetermined vibration time sequence, and according to an ultrasonic frequency, the time sequence being configured to cause a feeling of texturing of the plate by the external body touching the plaque.
- the vibration leads to a modification of the friction between the external body and the plate, which induces a perception of texturing.
- the haptic feedback can consist in setting the plate in vibration, according to a predetermined setpoint amplitude, for a short period, for example a few tens or hundreds of ms.
- the plate is vibrated according to a predetermined vibration amplitude.
- the plate can be vibrated so as to induce a haptic effect felt by the finger.
- the haptic effect forms a haptic feedback of the interface.
- a step 160 can be implemented, aimed at producing the haptic feedback.
- an actuation transducer 12 or each actuation transducer is connected to a switch 16.
- Each switch 16 is configured to connect the actuation transducer: - either to the circuit amplification 20: the plate then vibrates according to a spontaneous, self-sustained oscillation regime: the device then allows an estimation of a support force - either to an auxiliary power supply 18, imposing a setpoint signal according to a frequency setpoint and a setpoint vibration amplitude: the device then operates according to a conventional ultrasonic haptic interface.
- the actuating transducer 12 then behaves like an auxiliary transducer 14.
- the switch 16 can allow switching between the two modes: either the self-sustaining oscillation mode, when the actuation transducer is connected to the amplification circuit 20, so as to measure a pressing force; - or a forced vibration mode, according to a set frequency and amplitude, so as to induce haptic feedback.
- the actuation transducer then forms an auxiliary transducer.
- the invention can be applied to form a control interface for devices, for example devices for the general public, for example in the field of household appliances or the dashboard of vehicles. It can also be applied in interfaces of professional equipment.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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JP2023551193A JP2024507276A (ja) | 2021-02-24 | 2022-02-22 | 押圧力の強さを測定するためのタッチセンシティブインターフェース |
CN202280016448.5A CN116917845A (zh) | 2021-02-24 | 2022-02-22 | 允许测量按压力强度的触摸界面装置 |
EP22731993.6A EP4298497A1 (fr) | 2021-02-24 | 2022-02-22 | Interface tactile permettant une mesure d'une intensité d'une force d'appui |
KR1020237032864A KR20230149315A (ko) | 2021-02-24 | 2022-02-22 | 누르는 힘의 세기를 측정하기 위한 터치-감응 인터페이스 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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FR2101798A FR3120144B1 (fr) | 2021-02-24 | 2021-02-24 | Interface tactile permettant une mesure d’une intensité d’une force d’appui. |
FRFR2101798 | 2021-02-24 |
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WO2022189142A1 true WO2022189142A1 (fr) | 2022-09-15 |
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PCT/EP2022/054421 WO2022189142A1 (fr) | 2021-02-24 | 2022-02-22 | Interface tactile permettant une mesure d'une intensité d'une force d'appui. |
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EP (1) | EP4298497A1 (fr) |
JP (1) | JP2024507276A (fr) |
KR (1) | KR20230149315A (fr) |
CN (1) | CN116917845A (fr) |
FR (1) | FR3120144B1 (fr) |
WO (1) | WO2022189142A1 (fr) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2207080A1 (fr) * | 2008-12-23 | 2010-07-14 | Research In Motion Limited | Agencement d'actionneur piézoélectrique |
FR3061567A1 (fr) * | 2017-01-03 | 2018-07-06 | Hap2U | Interface tactile comportant un capteur de force |
US20190056837A1 (en) * | 2017-08-21 | 2019-02-21 | Apple Inc. | Unified Input/Output Interface for Electronic Device |
WO2020141264A1 (fr) | 2018-12-31 | 2020-07-09 | Hap2U | Actionneurs piézoélectriques à déformation amplifiée |
-
2021
- 2021-02-24 FR FR2101798A patent/FR3120144B1/fr active Active
-
2022
- 2022-02-22 JP JP2023551193A patent/JP2024507276A/ja active Pending
- 2022-02-22 CN CN202280016448.5A patent/CN116917845A/zh active Pending
- 2022-02-22 KR KR1020237032864A patent/KR20230149315A/ko unknown
- 2022-02-22 EP EP22731993.6A patent/EP4298497A1/fr active Pending
- 2022-02-22 WO PCT/EP2022/054421 patent/WO2022189142A1/fr active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2207080A1 (fr) * | 2008-12-23 | 2010-07-14 | Research In Motion Limited | Agencement d'actionneur piézoélectrique |
FR3061567A1 (fr) * | 2017-01-03 | 2018-07-06 | Hap2U | Interface tactile comportant un capteur de force |
US10860107B2 (en) | 2017-01-03 | 2020-12-08 | Hap2U | Touch-sensitive interface comprising a force sensor |
US20190056837A1 (en) * | 2017-08-21 | 2019-02-21 | Apple Inc. | Unified Input/Output Interface for Electronic Device |
WO2020141264A1 (fr) | 2018-12-31 | 2020-07-09 | Hap2U | Actionneurs piézoélectriques à déformation amplifiée |
Non-Patent Citations (3)
Title |
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LULEC SEVIL ZEYNEP ET AL: "MEMS cantilever sensor array oscillators: Theory and experiments", SENSORS AND ACTUATORS A: PHYSICAL, vol. 237, 28 November 2015 (2015-11-28), pages 147 - 154, XP029369394, ISSN: 0924-4247, DOI: 10.1016/J.SNA.2015.11.028 * |
ZHAO CHUN ET AL: "A Feasibility Study for a Self-oscillating Loop for a Three Degree-of-Freedom Coupled MEMS Resonator Force Sensor", PROCEDIA ENGINEERING, vol. 120, 11 September 2015 (2015-09-11), pages 887 - 891, XP029268510, ISSN: 1877-7058, DOI: 10.1016/J.PROENG.2015.08.766 * |
ZHAO CHUN ET AL: "A review on coupled MEMS resonators for sensing applications utilizing mode localization", SENSORS AND ACTUATORS A: PHYSICAL, ELSEVIER BV, NL, vol. 249, 25 July 2016 (2016-07-25), pages 93 - 111, XP029743267, ISSN: 0924-4247, DOI: 10.1016/J.SNA.2016.07.015 * |
Also Published As
Publication number | Publication date |
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FR3120144A1 (fr) | 2022-08-26 |
EP4298497A1 (fr) | 2024-01-03 |
CN116917845A (zh) | 2023-10-20 |
KR20230149315A (ko) | 2023-10-26 |
FR3120144B1 (fr) | 2023-07-21 |
JP2024507276A (ja) | 2024-02-16 |
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