Method for generating haptic feedback for an interface and associated interface

Description

[0001] The present invention relates to a method for generating sensory feedback for a motor vehicle interface. The present invention also relates to a motor vehicle interface configured for implementing said method.

[0002] WO 2018 / 219832 A1 describes a method for generating sensitive feedback for a motor vehicle interface. To simplify motor vehicle dashboards, manage different interface configurations, and improve their aesthetics, touch screens are increasingly being integrated inside the passenger compartment.

[0003] Basically, these screens are flat, but more recently touch screens have been developed with a certain curve that fits harmoniously into the dashboard of a car.

[0004] These screens allow the control of a large number of functions such as air conditioning, audio, telephone, navigation, driving aids, to name but a few, and contribute to the aesthetics of the interior of the passenger compartment. For car manufacturers, they also allow them to give a "signature" of their brand, also thanks to the graphic interfaces of the screens.

[0005] A touch screen therefore makes it possible to increase the number of functions that can be controlled by users with the advantage of being programmable and reconfigurable and able to be displayed temporarily or permanently depending on the context or the activated function. The screen thus includes a possibility of multifunctionality, while dematerializing the buttons and being customizable. These touch screens, whose cost tends to decrease, therefore make it easy to adapt to different models and different vehicle ranges.

[0006] Increasingly, touchscreens are equipped with sensitive feedback, such as haptic and / or audible feedback. Sensitive feedback can, for example, ensure the user that their command has been taken into account, which helps prevent dangerous situations from arising while driving.

[0007] Secondly, by integrating a touch screen, we also want to simulate for the user an environment that he knows. Indeed, screens allow for example to display images that can contain objects, such as reliefs or buttons. The user has, through the play of lighting and shadow effects, a visual perception in relief of the displayed object. Certain other images or areas of the image display a surface with a certain surface texture. The visual rendered is, depending on the display quality of the screen, increasingly close to the real perception of the object displayed by a user.

[0008] Recent developments propose to further associate a sensitive feedback with the relief of the image displayed on the touch screen for a rendering very similar to that of a 3D relief of a real object. In this case, the haptic feedback not only has the function of confirming or validating a user choice, but also, from a generally smooth interface, of giving him a surface perception in accordance with a displayed image or object.

[0009] For example, a haptic pattern is associated at least in certain areas of the image to simulate for the user a feeling close to the visual pattern displayed.

[0010] For example, we know of a texture simulation process that associates a specific haptic pattern with different areas of the screen.

[0011] For example, to simulate a vertical ridge texture, areas that mirror the shapes of the ridges are defined on the image for each "rib" or "groove" and a different haptic pattern is associated with each area of ​​different appearance.

[0012] In operation, when the user's finger moves horizontally across the smooth surface of the touchscreen over the succession of ridges displayed by the screen, it perceives haptic patterns generated alternately reminiscent of the vertical ridges that it simultaneously views on the screen. The aim is therefore to bring the user's haptic perception into agreement with the image or object displayed on the screen.

[0013] This haptic perception of texture, also called “haptic texturing” in English, can however sometimes lack realism.

[0014] This is the case, for example, when the user perceives a gap between the location of a haptic sensation of a relief on the screen and its visualization. Such a gap can occur, for example, when the user quickly moves their finger on the screen.

[0015] This can also be the case when the user moves his finger in different directions and does not perceive texture changes depending on the direction of finger movement while viewing asymmetric textures on the screen.

[0016] These inaccuracies in haptic sensation are due in particular to the calculation time required to process the information.

[0017] To improve this, one solution is to perform direction and trajectory calculations that take into account, in particular, the speed of movement of the finger, the pressure of the finger exerted on the screen or the direction of movement of the finger to determine the haptic effect to be generated. These calculations attempt, for example, to anticipate the movement of the finger on the screen to better synchronize the perception of the generated haptic feedback with the texture displayed on the screen so that it is as realistic as possible.

[0018] Using the example of vertical grooves, we measure, for example, the direction of finger movement to adapt the haptic pattern depending on whether the user moves their finger horizontally or vertically. We also measure the speed of finger movement to anticipate the trajectory and adapt the pattern of haptic feedback generated to the increase in finger movement speed.

[0019] However, these calculations require a lot of computing resources.

[0020] Additionally, there are still imperfections in the perception of haptic feedback.

[0021] These imperfections in perception are mainly due to the calculation time required, in particular to measure the speed and direction of movement of the user's finger on the touch screen and then to calculate the haptic feedback to be generated which corresponds to this particular data.

[0022] Another imperfection comes from the impossibility of accounting with the haptic feeling of the interaction, for example, of the finger as a control element with a deformable relief in the real world. Indeed, if we assume in the real world a 3D surface with small ribs or protuberances made of elastic material, depending on the material, in particular its elasticity, and the pressure force applied on such a relief, the haptic perception by the user when sliding his finger on this relief is different. Indeed, the greater the pressure force and the more elastic the material, the more the user will "crush" in real mode the raised parts and "erase" in some way the surface roughness. On the other hand, for example for a very rigid "stone" relief with no elasticity, there is no this erasing or crushing effect.

[0023] Furthermore, the known solutions are static images, that is to say that, although the displayed image allows the user to perceive a certain relief, such as grooves and ribs, and through adapted feedback, the user haptically perceives this relief, the known solutions do not allow for an evolving interaction between the displayed relief on the one hand and the haptic feedback on the other. As a result, the haptic and visual representation may appear somewhat rigid to the user.

[0024] One of the aims of the present invention is therefore to remedy at least partially at least one of the above drawbacks by proposing a method for generating sensitive feedback for a more efficient motor vehicle interface, which makes it possible to add a component relating to dynamic interaction with the user.

[0025] The claims define the invention.

[0026] Other characteristics and advantages of the invention will emerge from the following description, given by way of example and without limitation, with reference to the appended drawings in which: [ Fig.1 ] shows a front part of a motor vehicle interior, [ Fig.2 ] represents a schematic / synoptic side view of an interface, [ Fig.3 ] represents a perspective view of an example of a part of a textured surface in its unconstrained virtual space, [ Fig.4 ] represents a perspective view of an example of a textured surface according to the figure 3 in his virtual space with the tap of a finger, [ Fig.5 ] represents an example of an interface with dynamic texturing evolving over time.

[0027] In these figures, identical elements have the same reference numbers.

[0028] The term "procedural texture" is a term used in digital graphics. In this context, a procedural texture is a texture that is created from a mathematical description (e.g., an algorithm) and not from data stored, for example, in bitmap format as an image. This method has the advantage that textures can be very precise and are resolution-independent. Procedural textures can be, for example, 2D or 3D and are often used to represent natural materials such as wood, granite, metal, or stone.

[0029] The "natural" appearance of these procedural textures is usually achieved by using fractal noise or turbulence functions which can be used as a representation of randomness observed in nature.

[0030] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the characteristics apply only to a single embodiment.

[0031] There figure 1 shows a schematic view of a front portion of a motor vehicle passenger compartment 10 seen from the rear portion of the vehicle.

[0032] The passenger compartment 10 comprises in particular a driver's seat C arranged behind a steering wheel 11 and a dashboard 12, a passenger seat P, an interior rearview mirror 14, a ceiling light module 15, also called a dome, placed near the interior rearview mirror 14 in the upper central part of the front part of the passenger compartment 10 and a central console 13 located between the two seats of the front part of the passenger compartment 10, an interface 1 being mounted in the dashboard 12. Of course, the interface 1 can be arranged in other places in the passenger compartment 10 such as for example at the level of the central console 13 or any other suitable place.

[0033] As can be seen on the figure 2 showing a schematic view of the interface 1, the interface 1 comprises a screen 4, a touch surface 3 arranged above the screen 4 and a sensitive feedback device 20. The screen 4 and the touch surface 3 form a touch screen 2.

[0034] According to an exemplary embodiment, the interface 1 allows for example the control of at least one function of a motor vehicle component, in particular to control functions of an air conditioning system, an audio system, a telephone system or a navigation system. The interface 1 can also be used for example to control interior lights, central locking, a sunroof, hazard lights or ambient lights. This interface 1 can also be used for window regulator controls, exterior mirror positioning controls or even motorized seat movement controls. It allows for example the selection of a destination postal address or a name in a directory, the settings of the air conditioning system, the activation of a function, the selection of a music track from a list.

[0035] The touch surface 3 is for example a capacitive touch screen equipped with means for determining or measuring a pressing force applied to the touch surface 3.

[0036] The capacitive touch screen here comprises at least one capacitive sensor 31, a front plate 32 arranged on the capacitive sensor 31 and a controller 33.

[0037] The capacitive sensor 31 makes it possible to detect a variation in capacitance at the surface of the front plate 32. The capacitive touch screen can detect and determine the spatial coordinates in X and Y, for example, of a control element touching the touch surface 3.

[0038] The control element may be a finger or other activation means (e.g., a stylus) of the user.

[0039] The capacitive sensor 31 and the front plate 32 are at least partially transparent. The capacitive sensor 31 is for example formed from an array of electrodes extending over all or part of the surface of the slab. The electrodes are for example made of ITO (indium-tin oxide) which allow the sensor 31 to be transparent.

[0040] The rigidity of the capacitive touch screen is achieved by means of the rigid front plate 32 (or contact plate), such as a glass or polycarbonate plate. The front plate 32 arranged on the capacitive sensor 31 faces the user once mounted in the passenger compartment.

[0041] The screen 4, such as a TFT screen (“Thin-Film Transistor” in English) or an OLED screen or an LCD screen, is for example configured to display information or images in particular associated with the manipulation of the interface 1.

[0042] The screen 4 is arranged under the capacitive sensor 31. The screen 4 is configured to display an image formed of a predetermined number of pixels each identified by a position in the image X, Y. A pixel is a basic surface element (rectangular or square) of a digital image. A pixel can be formed of several sub-pixels: red, green, blue for example. For example, a screen 4 with a resolution of 480*800 has 384000 pixels.

[0043] The images displayed by the screen 4 can be of any kind, in particular digital synthetic images, notably in color.

[0044] The touch surface 3 comprises at least one active zone Z. The active zone(s) Z may extend over part or all of the interface 1. Contact of the control element in the active zone Z may allow control of the sensitive feedback device 20.

[0045] In the active area Z, for example, an image of a textured object is displayed, as will be described in more detail later.

[0046] The touch surface 3 is configured to locate the X, Y position of the control element on the touch surface 3 as well as to determine the pressing force.

[0047] For this purpose, the interface 1 comprises at least one pressure sensor 23 configured to measure a parameter representative of a pressure force exerted on the touch surface 3 ( figure 2 ).

[0048] The pressure sensor 23 is for example a capacitive sensor configured to measure a distance separating the mobile part from the fixed part in a direction perpendicular to the surface of the touch screen 2. A variation in distance between the mobile part and the fixed part is a parameter representative of pressure exerted on the touch screen 2. For a concrete example of embodiment, one can for example refer to the interface described in the document EP3340022 in the name of the Applicant.

[0049] The measurement of the contact force can also be carried out by other means, such as inductive measurement or ultrasonic measurement or deformation measurement using strain gauges or FSR (Force Sensing Resistor) sensors. To measure the contact force, the touch surface 3 is, for example, mounted floating or suspended in a support frame (not shown) with a strain gauge inserted between the support frame and the touch surface 3.

[0050] The sensitive feedback device 20 is configured to generate sensitive feedback, for example haptic and / or sound, upon receipt of a control signal.

[0051] To do this, the sensory feedback device 20 comprises a haptic feedback module 21 and / or a sound feedback speaker 24.

[0052] Such a control signal for sensory feedback comprises, for example, a control signal from the haptic feedback module 21 and / or a control signal from the sound feedback loudspeaker 24 and / or an absence of sensory feedback.

[0053] The sound feedback from the sound feedback speaker 24 may have different patterns and / or frequencies and / or amplitudes and / or durations.

[0054] “Haptics” means tactile feedback with physical contact with the touchscreen 2.

[0055] Haptic feedback can be achieved, for example, by vibrating the touchscreen 2, either in a direction parallel to a plane defined by the screen 4 or in a direction perpendicular to this plane. Haptic feedback is then feedback by touch. Thus, haptic feedback is a vibratory or vibrotactile signal.

[0056] The control signal of the haptic feedback module H can have different patterns and / or frequencies and / or phase shifts and / or amplitudes and / or durations, generally between 20 and 30msec. The pattern (or shape or form) has for example a so-called simple shape: linear, square, half-sine, triangle, etc. or a so-called complex shape comprising a combination of simple shapes or a curve. The pattern can also be symmetrical or asymmetrical as a function of time depending on the effect that one wishes to simulate. A pattern is symmetrical as a function of time if the duration of movement in one direction of movement is equal to that in the opposite direction. A pattern is asymmetrical as a function of time if the duration in one direction of movement is longer or shorter than that in the opposite direction.

[0057] For this, the haptic feedback module comprises at least one vibratory actuator 21 connected to the touch screen 2.

[0058] The vibratory actuator 21 is for example of the ERM (for "Eccentric Rotating-Mass" in English) type, also called a "vibrating motor" or mass motor. According to another example, the vibratory actuator 21 is of the electromagnetic type (solenoid). It can also be based, for example, on a technology similar to that of the Loudspeaker (in English: "Voice-Coil"). The vibratory actuator 21 is for example an LRA (for "Linear Resonant Actuator" in English), also called a "linear motor". According to another example, the vibratory actuator 21 is of the piezoelectric type.

[0059] The haptic feedback is a vibration signal such as a vibration produced by a sinusoidal control signal or by a control signal comprising one or a succession of pulses, sent to the vibration actuator 21. The vibration is for example directed in the plane of the touch screen 2 or orthogonally to the plane or even directed in a combination of these two directions.

[0060] The touch screen 2 and the vibratory actuator 21 are for example elements of a mobile part of the interface 1 which is connected by at least one damping element to a fixed part intended to be fixed to the motor vehicle.

[0061] The sensitive feedback device 20 may further comprise a processing unit 26 having one or more microcontrollers, having memories and programs adapted in particular to implement the method of generating a sensitive feedback from the interface, to modify the display of the screen 4, to process the information provided by the touch surface 3. This is for example the on-board computer of the motor vehicle.

[0062] The interface 1 further comprises a procedural texture generation unit 28. This procedural texture generation unit 28 comprises one or more microcontrollers, having suitable memories and programs. These may be dedicated microcontrollers and memories, but they may also be the same components as those used for the processing unit 26, used in a shared manner. As explained above, the procedural textures are generated from mathematical models and by using, for example, fractal or turbulence functions.

[0063] For an example of a procedural texture generation unit, one can refer for example to document US 6,674,433 or to document EP 2,599,057. These two documents describe how a textured object can be generated and modeled in a virtual space, i.e. its mathematical representation. Software for editing and generating procedural textures is for example marketed under the name "SUBSTANCE" (registered trademark) by the company Allegorithmic (registered trademark). In these documents, only visual effects for processing textured objects in a virtual space are discussed.

[0064] Therefore, in the present invention, the procedural texture generation unit 28 is configured to model a textured object and to display an image of the textured object on the screen 4. The textured object is therefore modeled in a virtual space.

[0065] A textured object is a broadly defined object with an external surface that has specific features. A textured object could be, for example, a dashboard covering, such as leather, or a control button.

[0066] An example of a textured object 30 is shown in the figure 3 . It is a membrane 50 in particular in the form of a flat disc, for example in leather and with squared seams 52 of the quilted leather type.

[0067] In the real world, if you touch a quilted leather object, you can feel the roughness of the leather as well as the furrows / grooves formed by the grid seams 52. You can also depress the membrane 50 by pressing on it.

[0068] In the real world, an object can be characterized by its surface aspects, its roughness, its asperities, its deformability / elasticity depending on external constraints or environmental factors.

[0069] Procedural texture generation unit 28 allows to represent in a virtual space (by modeling) such a real object with its characteristics.

[0070] A virtual representation corresponds to a mathematical description of the textured object 30 with its characteristics, in particular using a suitable mesh, for example in the form of a 3D polygon mesh as is used in video games to obtain a visual surface rendering close to reality.

[0071] The procedural texture generation unit 28 is also programmed to be able to calculate modifications to the textured object 30 based on its deformation properties, for example.

[0072] So, as shown on the figure 4 , a force F applied to the membrane 50 will have the effect of creating a hollow 56 or indentation in the center of the membrane 50.

[0073] As seen on the figure 2 , the procedural texture generation unit 28 is connected on the one hand to the controller 33 of the capacitive sensor 31 and on the other hand to the support sensor 23.

[0074] It therefore receives as input the X and Y position of the pressure as well as the pressure force applied to the touch surface 32 by a control element such as for example a user's finger or a stylus.

[0075] Taking into account this input data, the procedural texture generation unit 28 is programmed to calculate the modifications on the textured object 30 in its virtual space, in particular changes in shape, as for example represented on the figure 4 The support force with its location are therefore also modeled and transposed into the virtual space, that is to say the mathematical space in which the textured object 30 is represented.

[0076] The procedural texture generation unit 28 therefore determines by transposition of the X, Y support position as well as the support force of the control element in the virtual space where the textured object 30 is modeled an interaction of the textured object 30 with the control element.

[0077] Then, the procedural texture generation unit 28 controls the sensitive feedback device 20 according to the determined effect of the interaction on the textured object 30, which results in the user feeling a haptic effect that resembles what he could feel on a real object, while his finger is only placed on a smooth touch screen 3.

[0078] A finger depression can for example be simulated by asymmetric accelerations perpendicular to the touch surface and generated by the sensitive feedback device 20, i.e. for example rapid downward acceleration cycles (with reference to the arrangement of the figure 2 ) followed by a slower ascent. Edge or rib effects can be achieved by rapid upward accelerations.

[0079] Of course, the procedural texture generation unit 28 also displays on the screen 4 the effect of the interaction on the textured object 30, such as for example the deformation, for example as on the figure 4 . An acoustic signature as sound feedback accompanying the effect of the interaction on the textured object 30 may also be emitted by the loudspeaker 24. In the present example, the sound signature may be that of a finger rubbing on leather.

[0080] On the figure 5 another example of an embodiment of the interface is shown.

[0081] On this figure 5 , at the bottom, an image of a textured object 30 displayed by the touch screen 2 is shown in reference 100.

[0082] In this example, unlike the example of the figures 3 et 4 , the textured object is not static at the start, but it is a relief which moves over time, for example in a back and forth movement as indicated by the double arrow F2. The textured object 30 is therefore in the form of a dynamic surface varying over time such as waves which when a force is applied to them, crush due to a certain elasticity of deformation.

[0083] This textured object 30 is generated from a mathematical model which is indicated in a simplified manner above the image 100 by a curve 102. These are, for example, sinusoidal functions, the peaks of which move in a back and forth movement along the surface of the touch screen 2.

[0084] When the touch surface 2 is pressed, the procedural texture generation unit 28 modifies the textured object 30, here the waves, for example by crushing and spreading them. This effect of the interaction will be visible on the touch screen 2 by the user and will also be perceptible by him since the unit 28 will control the sensitive feedback device 20 accordingly. By increasing the pressing force, the user will perceive a greater spreading / flattening of the waves.

[0085] We can also make another use of the image of the textured object of the figure 5 . Suppose the textured object in image 100 is initially fixed and flat, for example like a body of water.

[0086] Pressing the touchscreen 2 generates a hollow and waves where the finger is placed on the surface and, when the finger moves, the waves move with the finger, the point of support always corresponding to a hollow.

[0087] In this case also, it is the procedural texture generation unit 28 which will first generate the deformations of the textured object in the virtual space and then control the sensitive feedback device 20 on the one hand and the touch screen 2 for displaying the deformation of the textured object 30 on the other hand.

[0088] Generally speaking, other cases can also be observed. Depending on the pressure exerted (P=F / S) and depending on the simulated rigidity of the texture (for example plastic or metal) and depending on the surface condition of the textured object, for example a large grain of very solid surface, of significant roughness, the surface is supposed to deform under the force of the support but not the surface grain which remains constant for example.

[0089] In this case, the procedural texture generation unit 28 can take into account in virtual space that the surface of the textured object, for example a plate with bumps, deforms, but not the bumps themselves.

[0090] The effect of the interaction of the textured object 30 in the virtual space may, for example, take into account the tangent angle of the surface deformed upon contact, the average static and dynamic friction coefficient of the finger on the surface as a function of the simulated material, or even the speed of movement of the finger on the touch surface.

[0091] According to another case, as explained with regard to the figures 3 et 4 , the procedural texture generation unit 28 can take into account that the texture grain (for example bumps) evolves depending on the pressure.

[0092] In this case, the procedural texture generation unit 28 takes into account macroscopic deformation (surface deformation) and microscopic deformation (bump deformation) depending on the applied pressure.

[0093] The textured object 30 can also, for example, represent a control button, a keyboard key or a scroll cursor (or “slider” in English).

[0094] In this case, for example, the procedural texture generation unit 28 can, for example, simulate the pressing of the button as a function of pressure exerted on the touch surface 3 and control the sensitive feedback device 20 so that the user feels the pressing of the finger on the one hand and hears, for example, a mechanical switch click.

[0095] It is therefore understood that the interface according to the invention makes it possible to considerably broaden the field of application of touch screens with haptic feedback 4.

Claims

1. A method of generating sensory feedback for a motor vehicle interface (1) comprising : - a screen (4) configured to display an image, - a tactile surface (3) arranged above the screen (4) and configured to locate the position (X, Y) and to determine a pressure force of a control element on the tactile surface (3), - a sensory feedback device (20) configured to generate sensory feedback when a control signal is received, and - a procedural texture generation unit (28) configured to model a textured object (30) and to display an image of the textured object (30) on the screen (4), - displaying the image of the textured object (30) generated by the procedural texture generation unit (28) on the screen (4), characterized in that - by taking into account the location on the tactile surface (3) and the pressure force (F) of the control element, an interaction of this control element with the textured object (30) is modelled, - the effect of the interaction on the textured object (30) is determined, - the sensory feedback device (20) is controlled as a function of the determined effect of the interaction on the textured object (30), wherein the effect of the interaction on the textured object is displayed on the screen (4) and wherein the procedural texture generation unit (28) takes into account at least one of the following parameters from the parameter group when modeling the textured object (30): roughness of the textured object, deformability of the material of the textured object, elasticity of the textured object, displacement or movement of the textured object.

2. Method according to claim 1, wherein the textured object (30) corresponds to a dashboard covering, in particular a skin, for example leather or a control knob.

3. Method according to claims 1 to 2, in which the textured object (30) has a dynamic surface that varies over time, in particular in the form of waves.

4. Method according to any one of claims 1 to 3, in which sound feedback is emitted to accompany the effect of the interaction on the textured object (30).

5. Method according to any one of claims 1 to 4, in which the textured object (30) is represented in the form of a 3D polygon mesh.

6. A motor vehicle interface comprising : - a procedural texture generation unit (28) configured to model a textured object (30) and to display an image of the textured object (30), - a screen (4) configured to display the image of the textured object (30) generated by said procedural texture generation unit (28), - a tactile surface (3) arranged above the screen (4) and configured to locate the position (X, Y) as well as to determine a pressure force (F) of a control element on the tactile surface (3), and - a sensory feedback device (20) configured to generate sensory feedback on receipt of a control signal, characterized in that the procedural texture generation unit (28) is configured - to model an interaction of the control element with the textured object (30), taking into account the location on the tactile surface (3) and the pressure force (F) of the control element, - to determine the effect of the interaction on the textured object (30), and - to control the sensory feedback device (20) as a function of the determined effect of the interaction on the textured object (30), and the procedural texture generation unit (28) is configured to display on the screen (4) the effect of the interaction on the textured object and to take into account when modeling the textured object (30) at least one of the following parameters from the group of parameters : roughness of the textured object, deformability of the material of the textured object, elasticity of the textured object, displacement or movement of the textured object.

7. Interface according to claim 6, wherein the textured object (30) corresponds to a dashboard t covering, in particular a skin, for example leather or a control knob.

8. Interface according to any one of claims 6 to 7, wherein it further comprises an acoustic transmitter (24) configured to emit an acoustic signature accompanying the effect of the interaction on the textured object (30).

9. An interface according to any one of claims 6 to 8, in which the textured object (30) in virtual space is represented in the form of a 3D polygon mesh.