Wearable interface device for tactile rendering

Abstract

A wearable interface device (1) for tactile rendering, comprising: - a wearable container body (10) externally applicable to a portion (100) of an individual's body, said wearable container body (10) defining a contact surface (11) adapted to be placed in contact with said at least one portion (100) of an individual's body, and an opposite external surface (12), wherein said contact surface (11) comprises an actuated surface portion (13) capable of deforming to transfer tactile pressure to at least one sensitive portion of said portion (100) of an individual's body, said tactile pressure varying as a function of an actuation signal; a pressure chamber (14), containing a fluid, in fluid communication with said actuated surface portion (13), said pressure chamber (14) being contained within said wearable container body (10); an actuator (20) in contact with said pressure chamber (14), configured to vary the volume of said pressure chamber (14) and thus to vary the pressure of said fluid in said pressure chamber (14), and thus to actuate said actuated surface portion (13) as a function of said actuation signal, said actuator (20) being contained inside said wearable container body (10).

Description

WEARABLE INTERFACE DEVICE FOR TACTILE RENDERINGDESCRIPTIONField of the invention

[0001] The present invention relates to a wearable interface device for tactile rendering, in particular for use in immersive virtual scenarios or teleoperation capable of providing the user with sensory feedback suitable for remote interaction .Background art

[0002] In the context of interaction in immersive virtual scenarios or teleoperation, touch provides crucial information for ef ficiently performing manipulation tasks .

[0003] However, the current commercial immersive virtual and telepresence technologies have reached a fairly high degree of evolution for vision and audio , while almost completely excluding the sense of touch .

[0004] As for the known commercial devices , interaction mainly occurs through j oysticks , in which tactile feeling is given at a very general level of vibrotactile stimuli .

[0005] Only recently, 3D viewers have been known, in which user interaction in the virtual environment through the movement of hands has been introduced, the tracking systems of which are based on vision and arti ficial intelligence arranged in the viewer itsel f by means of amicro-camera system . This innovation allows directly interacting with the movement of limbs and hands in immersive virtual environments , making the importance of adding tactile feedback during the interaction even greater .

[0006] There are few known commercial interface devices capable of returning a tactile feedback to the user .

[0007] Prototype interface devices exist , which allow providing rich, finely modulated feedback, but they are very bulky and heavy, impossible to use on terminal parts of a user ' s body, e . g . , on the fingertips of the fingers of a hand .

[0008] This category includes , for example , hydraulic-type interface devices having pneumatic or hydraulic actuators , which require , however, remote actuation units , such as electric motors with pumps , flexible pipes extending from the remote actuation unit to the interface device in contact with the user, thus making the use impossible in dynamic virtual environments in which hand dexterity and user mobility are relevant .

[0009] Such known devices are not miniaturi zable .

[0010] On the other hand, the known devices capable of providing tactile feedback and which are small in si ze and lightweight do not allow providing a tactile feedback which is rich from the point of view of frequencycomponents , with fine modulation, with a linear and continuous response , but instead only with a vibrotactile response .

[0011] Therefore , the need is felt to provide a wearable interface device , thus small in si ze , compact and lightweight , but at the same time capable of providing high-intensity and rich tactile feedback, continuously varying in a linear and non-cyclic manner, suitable for high-quality, low-noise rendering with high dynamics . Summary of the invention

[0012] It is the obj ect of the present invention to devise and provide a wearable interface device for tactile rendering, which allows meeting the aforesaid needs and at least partially obviating the drawbacks complained of above with reference to the prior art .

[0013] In particular, it is the task of the present invention to provide a wearable interface device for tactile rendering, which is wearable , small in si ze , compact , and lightweight , but at the same time capable of providing high-intensity and rich tactile feedback, continuously varying in a linear and non-cyclic manner, adapted to high-quality, low-noise rendering with high dynamics .

[0014] These and further obj ects and advantages are achieved by a wearable interface device for tactilerendering according to independent claim 1 .

[0015] Advantageously, the direct coupling of the fluid circuit with the linear actuator allows the introduction of an advantageous pneumatic / hydraulic reduction ratio compared to other miniaturi zed actuators because the pneumatic reduction does not introduce noise and nonlinearity into the rendered signals .

[0016] Advantageously, such a direct coupling allows eliminating hydraulic pipes of signi ficant length, generally used in prototype devices , which introduce a signi ficant delay in signal propagation from the actuator to the user .

[0017] Moreover, such a direct coupling allows innovative designs of the interface device , e . g . , by providing highly wearable distributed actuated parts .

[0018] Further obj ects , solutions , and advantages are present in the embodiments described below and claimed in the dependent claims .Brief description of the drawings

[0019] The invention will be shown below by describing embodiments thereof , given by way of non- limiting example , with reference to the accompanying drawings , in which :

[0020] - figure 1 shows a section view of an embodiment of a wearable interface device according to the invention,through a longitudinal section plane ;

[0021] - figure 2 shows a diagrammatic view of the wearable interface device in figure 1 , in which the container body was removed for ease of viewing;

[0022] - figure 3 shows a perspective view of the wearable interface device in figure 1 , applied to a distal phalanx of the finger of a wearer ;

[0023] - figure 4 shows a diagrammatic section view of an embodiment of a wearable interface device according to the invention comprising an adj ustment chamber ;

[0024] - figure 5 shows a diagrammatic section view of an embodiment of a wearable interface device according to the invention, in which each pole piece comprises an end portion of the magnetic piston and a ring-shaped element made of ferrofluid material arranged about said end portion of the magnetic piston;

[0025] - figure 6 shows a diagrammatic section view of an embodiment of a wearable interface device according to the invention in which the piston has a central extension portion and two magnets arranged at the two opposite free ends of said central extension portion;

[0026] - figure 7 shows an isometric view of an interface device according to the invention;

[0027] - figure 8 shows the partial isometric view in figure 7 , depicted in section through a section planecutting the container body and the actuated surface . Description of preferred embodiments

[0028] With reference to the figures , a wearable interface device for tactile rendering according to the invention is indicated, as a whole , by reference numeral 1 .

[0029] The wearable interface device 1 performs the tactile rendering function, i . e . , of transmitting a tactile pressure signal provided by a remote system to a sensitive portion of an individual ' s body, e . g . , the fingertip of a phalanx .

[0030] Such a wearable interface device 1 comprises a wearable container body 10 externally applicable to a portion 100 of an individual ' s body, said wearable container body 10 defining a contact surface 11 adapted to be placed in contact with said at least one portion 100 of an individual ' s body, and an opposite external surface 12 .

[0031] The contact surface 11 comprises at least one actuated surface portion 13 capable of deforming to trans fer a tactile pressure to at least one sensitive portion of said portion 100 of an individual ' s body, said tactile pressure varying as a function of an actuation signal .

[0032] According to an embodiment , such an actuation signal is provided by a remote signal source .

[0033] According to an embodiment , such an actuation signal can be generated by an external , preferably remote , electronic control unit connectable to said wearable interface device 1 and programmed to generate said actuation signal as an output as a function of an input , e . g . , provided by an operator or software program .

[0034] Such an electronic control unit can be specially designed or can generally be a computer or a programmable electronic device .

[0035] The electronic control unit does not belong to the wearable interface device 1 .

[0036] The interface device 1 comprises a pressure chamber 14 containing a fluid, in fluid communication with the at least one actuated surface portion 13 , where the pressure chamber 14 is contained inside the wearable container body 10 .

[0037] The interface device 1 further comprises an actuator 20 in contact with said pressure chamber 14 , configured to vary the volume of said pressure chamber 14 and thus to vary the pressure of said fluid in said pressure chamber 14 , and thus to actuate said at least one actuated surface portion 13 as a function of said actuation signal , where the actuator 20 is contained inside said wearable container body 10 .

[0038] In other words , the wearable container body 10contains therein the various components described above , thus forming a sel f-contained device .

[0039] This means that the interface device according to the invention allows avoiding the need for external remote actuators .

[0040] According to an embodiment , the actuation signal is at least partially variable in a linear and continuous manner .

[0041] According to an embodiment , the actuator 20 is a linear actuator, comprising a cylinder 21 and a piston 22 movable in said cylinder 21 .

[0042] According to an embodiment , the cylinder 21 forms part of said pressure chamber 14 .

[0043] The complete integration of the actuator 20 inside the wearable body 10 is thus achieved .

[0044] In other words , according to such an embodiment , the pressure chamber 14 is designed to be itsel f an integral part of the cylinder 21 of the linear actuator 20 , preferably with shape continuity .

[0045] According to an embodiment , the linear actuator 20 is an electromagnetic actuator and comprises at least one electrical winding 23 about said cylinder 21 , and where said piston 22 is magnetic so as to be actuated by means of said electrical winding 23 .

[0046] The at least one electric winding 23 is configuredto generate an electromagnetic field, and the piston 22 comprises at least one magnet 26 , 26 ' operable by means of said electromagnetic field generated by said electric winding 23 .

[0047] In this case , the actuation signal is an electrical signal , e . g . , transmitted through an electrical conductive cable 30 .

[0048] According to an embodiment , the linear actuator 20 comprises at least one fluid-tight element 24 interposed between said piston 22 and said cylinder 21 .

[0049] According to an embodiment , the at least one fluid- tight element 24 comprises a pole piece 25 made of a ferrofluid material comprising a liquid containing ferromagnetic nanoparticles .

[0050] According to an embodiment , the pole piece 25 comprises an end portion 29 of the magnetic piston and a ring-shaped element made of ferrofluid material arranged about said end portion 29 of said magnetic piston 22 .

[0051] According to an embodiment , such an end portion 29 is made of a material having a greater magnetic permeability than the magnetic permeability of the ferrofluid, e . g . , such a material either is or comprises iron or steel .

[0052] The intensity and orthogonality of the magnetic field with respect to the movement direction of themagnet is thus increased, the geometric dimensions being the same .

[0053] According to an embodiment , the piston 22 comprises a central extension portion 27 made of ferromagnetic material and two magnets 26 , 26 ' arranged at the two opposite free ends of said central extension portion 27 .

[0054] This allows obtaining an actuator with a high piston stroke , e . g . , to increase the volume variation allowed on the actuated surface .

[0055] Instead of a single magnet , two smaller magnets can be more conveniently used, connected by the rigid, ferromagnetic central portion .

[0056] Preferably, the at least one fluid-tight element 24 comprises two pole pieces 25 made of ferrofluid material arranged at the free ends of the piston 22 to support the piston and allow it to slide without sliding contact with cylinder 21 .

[0057] The ferrofluid material forms a very low- friction, fluid-tight cushion of the pressure chamber 14 , capable of supporting relatively large displacements of the movable element .

[0058] According to an embodiment , the at least one actuated surface 13 is defined by a flexible wall portion of said pressure chamber 14 .

[0059] According to an embodiment , the container body 10 isin the shape of a thimble adapted to be worn on said portion 100 of an individual ' s body, where said portion 100 of an individual ' s body is a distal phalanx of a finger of said individual , where said contact surface 11 is defined by a cavity 16 in said container body 10 in the shape of a thimble , adapted to accommodate and wrap said distal phalanx, and where said at least one actuated surface portion 13 is arranged in a side portion 11 ' of said cavity 16 adapted to be arranged in contact with a fingertip of said distal phalanx .

[0060] According to an embodiment , the side portion 11 ' of said cavity 16 belongs to a shel f-like portion of said container body 10 .

[0061] According to an embodiment , the at least one actuated surface portion 13 is made of silicone rubber or flexible resin for 3D printing, preferably with silicone- like features .

[0062] According to an embodiment , the wearable container body 10 is made of a flexible material , such as silicone rubber or flexible resin for 3D printing, for example , preferably with silicone-like features .

[0063] According to an embodiment , the at least one actuated surface portion 13 comprises a plurality of actuated surface portions 13 distributed along said contact surface 11 .

[0064] According to an embodiment , said at least one actuated surface portion 13 is corrugated in shape .

[0065] The corrugated shape of the actuated surface 13 decreases the overall rigidity of the actuated surface , the thickness being the same .

[0066] The decrease in rigidity of the actuated surface facilitates the propagation of the tactile signals from the actuator to the user ' s tissues .

[0067] On the other hand, the minimum thickness of the actuated surface is determined by limits of robustness during both construction and use .

[0068] The corrugated surface is obtainable by means of the same 3D printing techniques already explained above .

[0069] According to an embodiment , the wearable interface device 1 comprises an adj ustment chamber 34 comprising volume variation means of said adj ustment chamber 35 , said adj ustment chamber 34 comprising a compressible fluid and being arranged in contact with said actuator 20 on the opposite side from said pressure chamber 14 so that a variation in volume of said adj ustment chamber 34 corresponds to an opposite variation in volume of said pressure chamber 14 .

[0070] According to an embodiment , the wearable interface device 1 comprises indication means of a rest position of said actuator 20 so as to allow operating said adj ustmentmeans 35 to bring said rest position of said actuator 20 at a predetermined zero position.

[0071] By adjusting the volume of the adjustment chamber, it is possible to adjust the position of the magnetic piston at rest, which is an important feature to extend the use of the interface device to differently sized fingers .

[0072] Indeed, larger or smaller finger sizes increase or decrease the volume at rest of the pressure chamber connected to the actuated surface, modifying the position of the magnetic piston at rest. The magnetic piston must ideally be centered with respect to the stroke provided in the linear actuator design.

[0073] According to an embodiment, the adjustment chamber is ideally rigid, with adjustable volume, filled with compressible fluid, e.g., air.

[0074] According to an embodiment, the adjustment means 35 comprise an assembly of a cylinder 36 and a piston 37 in which a relative position between said cylinder 36 and said piston 37 is adjusted by means of a screw 38.

[0075] In this case, the variation, by fine-tuning, in the volume of the secondary cavity results in a fine variation in the position of the magnet at rest.

[0076] Moreover, the overall volume of the adjustment chamber introduces pneumatic rigidity coupled with thepressure chamber . Such an additional rigidity can be defined during the design according to the frequencies of the signals to be rendered, in particular being sti f fer, thus with a smaller overall volume , for high frequencies and vice versa .

[0077] Advantageously, the wearable interface device 1 can be used in multiple application contexts .

[0078] The main purpose is tactile rendering in virtual environments since it allows perceiving the touch and the tactile interaction with high-quality signals in terms of intensity and dynamics .

[0079] Compared to other solutions , it has the advantage of better wearability and transmission of tactile signals due to the soft pneumatic interface , without the disadvantages of bulky actuators connected by means of pneumatic connections .

[0080] In the work environment , immersive virtual scenarios can be ef fectively used for simulation and training purposes , and in teleoperation as part of the control of remote robots ranging from maintenance to intervention in risky zones for human operators . In these areas , the tasks of interaction and manipulation with the environment can be relevant , as well as the need for tactile rendering of the virtual or remote scene .

[0081] Multiple applications can also be found in thegaming field where augmented reality and virtual reality are increasingly gaining ground, as well as in the scienti fic field where the study of the perception of high- fidelity tactile stimuli is constantly progressing .

[0082] Not least , the development of " serious games" , virtual games with neurorehabilitation purposes , greatly benefits from the inclusion of tactile feedback congruent with the patient ' s motor action .

[0083] Those skilled in the art may make changes and adaptations to the embodiments of the device described above or replace elements with others which are functionally equivalent in order to meet contingent needs without departing from the scope of the following claims . Each of the features described as belonging to a possible embodiment can be made irrespective of the other embodiments described .-k 'k 'k

Claims

CLAIMS1. A wearable interface device (1) for tactile rendering, comprising;- a wearable container body (10) externally applicable to a portion (100) of an individual's body, said wearable container body (10) defining a contact surface (11) adapted to be placed in contact with said at least one portion (100) of an individual's body, and an opposite external surface (12) , wherein said contact surface (11) comprises at least one actuated surface portion (13) capable of deforming to transfer tactile pressure to at least one sensitive portion of said portion (100) of an individual's body, said tactile pressure varying as a function of an actuation signal;- a pressure chamber (14) , containing a fluid, in fluid communication with said at least one actuated surface portion (13) , said pressure chamber (14) being contained within said wearable container body (10) ;- an actuator (20) in contact with said pressure chamber (14) , configured to vary the volume of said pressure chamber (14) and thus to vary the pressure of said fluid in said pressure chamber (14) , and thus to actuate said at least one actuated surface portion (13) as a function of said actuation signal, said actuator (20) being contained inside said wearable container body (10) .

2. A wearable interface device (1) according to claim 1, wherein said actuation signal is at least partially variable in a linear and continuous manner.

3. A wearable interface device (1) according to claim 1, wherein said actuator (20) is a linear actuator, comprising a cylinder (21) and a piston (22) movable in said cylinder (21) .

4. A wearable interface device (1) according to claim 3, wherein said cylinder (21) forms part of said pressure chamber ( 14 ) .

5. A wearable interface device (1) according to claim 3, wherein said linear actuator (20) is an electromagnetic actuator and comprises at least one electrical winding (23) about said cylinder (21) configured to generate an electromagnetic field and wherein said piston (22) comprises at least one magnet (26, 26' ) actuatable by means of said electromagnetic field generated by said electrical winding (23) .

6. A wearable interface device (1) according to claim 5, wherein said linear actuator (20) comprises at least one fluid-tight element (24) interposed between said piston (22) and said cylinder (21) .

7. A wearable interface device (1) according to claim 6, wherein said at least one fluid-tight element (24) comprises a pole piece (25) made of a ferrofluid materialcomprising a liquid containing ferromagnetic nanoparticles .

8. A wearable interface device (1) according to claims 5 and 7, wherein said pole piece (25) comprises a ringshaped element made of ferrofluid material arranged about an end portion (29) of said magnetic piston (22) .

9. A wearable interface device (1) according to claim 8, wherein said end portion (29) is made of a material having a higher magnetic permeability than that of the ferrofluid material.

10. A wearable interface device (1) according to claim 5, wherein said piston (22) comprises a central extension portion (27) made of ferromagnetic material and two magnets (26, 26' ) arranged at the two opposite free ends of said central extension portion (27) .

11. A wearable interface device (1) according to at least one preceding claim, wherein said at least one actuated surface portion (13) is defined by a flexible wall portion of said pressure chamber (14) .

12. A wearable interface device (1) according to at least one preceding claim, wherein said container body (10) is in the shape of a thimble adapted to be worn on said portion (100) of an individual's body, wherein said portion (100) of an individual's body is a distal phalanx of a finger of said individual, wherein said contactsurface (11) is defined by a cavity (16) in said container body (10) in the shape of a thimble, adapted to accommodate and wrap said distal phalanx, and wherein said at least one actuated surface portion (13) is arranged in a side portion (11' ) of said cavity (16) adapted to be arranged in contact with a fingertip of said distal phalanx.

13. A wearable interface device (1) according to claim 12, wherein said side portion (11' ) of said cavity (16) belongs to a shelf-like portion of said container body (10) .

14. A wearable interface device (1) according to at least one preceding claim, wherein said actuated surface portion (13) is made of silicone rubber or flexible resin for 3D printing.

15. A wearable interface device (1) according to at least one preceding claim, wherein said wearable container body (10) is made of silicone rubber or flexible resin for 3D printing .

16. A wearable interface device (1) according to at least one preceding claim, wherein said at least one actuated surface portion (13) comprises a plurality of actuated surface portions (13) distributed along said contact surface (11) .

17. A wearable interface device (1) according to at leastone preceding claim, wherein said at least one actuated surface portion (13) is corrugated in shape.

18. A wearable interface device (1) according to claim 1, comprising an adjustment chamber (34) comprising volume variation means of said adjustment chamber (35) , said adjustment chamber (34) comprising a compressible fluid and being arranged in contact with said actuator (20) on the side opposite to said pressure chamber (14) so that a variation in volume of said adjustment chamber (34) corresponds to an opposite variation in volume of said pressure chamber (14) .

19. A wearable interface device (1) according to claim 18, comprising indication means of a rest position of said actuator (20) so as to allow operating said adjustment means (35) to bring said rest position of said actuator (20) at a predetermined zero position.

20. A wearable interface device (1) according to claim 18, wherein said adjustment means (35) comprise an assembly of a cylinder (36) and a piston (37) , wherein a relative position between said cylinder (36) and said piston (37) is adjusted by means of a screw (38) .

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