DE102016106913A1 - Tactile display - Google Patents

Abstract

A tactile display for wearing on the head (H) of a user having a plurality of tactile actuators (T) attachable to a headgear for placement on the head (H) of the user and connectable to a control unit (S) will be described , The tactile actuators (T) are arranged distributed on at least two circular paths (K ₁ , K ₂ , K ₃ ), wherein the circular paths (K ₁ , K ₂ , K ₃ ) are angularly offset from each other.

Description

The invention relates to a tactile display for carrying on the head of a user with a plurality of tactile actuators attachable to a headgear for placement on the head of the user and connectable to a control unit.

The invention further relates to a method for controlling such a tactile display.

Tactile screens attachable to a user's head are used to provide haptic information to the user via visual representations of situations. This is done by individually controllable tactile actuators z. B. act by vibration on the head surface at defined positions of the head.

M. Berning, F. Braun, T. Riedel, M. Beigl: Proximity Hat - A Head-Worn System for Subtle Sensory Augmentation with Tactile Stimulation, in: ISWC '15, September 7-11, 2015, Osaka, Japan, p. 31 to 38 describes a for tactile guidance of blind in a room provided for with arranged on a circular path over the circumference of the hat ultrasonic sensors and these associated tactile actuators. Depending on the distance to a wall surface detected by an ultrasonic sensor, the respective associated tactile actuator is actuated in each case. This allows a user to be directed through a walled room without visual assistance.

GB 2 522 866 A discloses a belt for attachment to a body part of a user, such as the abdomen or head provided with a plurality of circumferentially arranged vibrators. To guide the user in the room, the vibrators can be controlled individually.

MK Dobrzynski, S. Mejri, S. Wischmann, D. Floreano: Quantifying Information Transfer Through a Head-Attached Vibrotactile Display: Principles for Design and Control, in: IEEE Transactions on Biomedical Engineering, Vol. 7, July 2012, pages 2011-2018 discloses a vibrotactile display with tactile actuators arranged around a single circumference on the user's forehead. The research found that directional detection decreased significantly with the number of simultaneously activated tactile actuators, so stimulation at several points should be avoided at the same time. Locating accuracy varies widely with the head region, but most areas on the front and back of the head should not be loaded with tactile actuators for high precision.

Proceeding from this, it is an object of the present invention to provide an improved tactile display that can pass on location information in three-dimensional space to the user as well as possible.

The object of the invention is also to provide an improved method for controlling such a tactile display.

The object is achieved by the tactile display with the features of claim 1 and by the method having the features of claim 12. Advantageous embodiments are described in the subclaims.

It is proposed that the tactile actuators of the tactile display are arranged distributed on at least two circular paths, wherein the circular paths are aligned angularly offset from each other. Particularly advantageous is the arrangement of the tactile actuators on three circular paths.

The arrangement of the tactile actuators not only on a circular path running on the forehead, but on several circular paths, the location sensitivity in three-dimensional space can be significantly improved. The arrangement of the tactile actuators on angularly offset from each other arranged circular paths, the haptic information is optimally adapted to the anatomy of the user's head.

One or more tactile actuators may be provided on a chin strap for placement on the user's chin. In this way, the directional sensitivity of the tactile display in three-dimensional space is further improved, in particular with respect to target information lying in the lower range in the direction of the user's gaze.

One or more tactile actuators may also be provided for placement on the neck of the user. This makes it possible to communicate destination information in the rear area of the user well below the head level.

The tactile display may have a 3D screen designed to be placed in front of the eyes for three-dimensional projection of images or videos. Thus, in addition to the haptic transmission of target information in three-dimensional space, optically three-dimensional spatial information about the visual sense of the user can also be transmitted.

The tactile actuators can be designed as piezo actuators, as inductively controllable actuators or similar vibration actuators. Especially Piezo actuators can be driven with low energy and are very compact.

It is advantageous if the tactile display adjacent to the ears of the user has no tactile actuators. Here a distance of more than 4 cm from the ears and preferably more than 5 cm should be respected. This takes into account the fact that the head of the user in the area of the ears is much more sensitive to the acoustic portion of tactile signals transmitted by bone conduction than in the remaining head area. The tactile actuators irritate adjacent to the ears not only the sense of touch of the user, but also the sense of hearing.

The control unit connected to the tactile display can be set up to simultaneously drive a group of adjacent tactile actuators. This can improve the directional accuracy for transmitting a target position in three-dimensional space to the user. For this purpose, the control unit can, for example, be set up to control the group of adjacent tactile actuators such that the intensity of the actuation of the tactile actuators of the group of at least one spatially central tactile actuator in the group surrounds the other tactile actuators surrounding this at least one central tactile actuator decreases. The intensity of the tactile actuators is thus interpolated depending on the target point to be communicated in the three-dimensional space so that the haptic impression of the at least one central actuator decreases towards the outside.

In this case, the control unit can be set up to control the tactile actuators of a group as a function of the intersection of a straight line leading from a target point in space to a defined head center of the tactile display with a target area spanned by the tactile actuators of the group. Due to the arrangement of the tactile actuators on the multiple circular paths, a common center of gravity is defined by the circular paths, which defines, for example, the head center of the tactile display. The actuation of the tactile display then takes place in such a way that from a target point to be communicated to the user in the three-dimensional space in the vicinity of the user a straight line to the defined head center is determined. This line then cuts a target area spanned by a group of tactile actuators. This intersection is now used to determine the intensity of the actuation of the tactile actuators of this group. In this case, these tactile actuators of the group can each be controlled with an intensity such that the haptic impression in the region of this intersection is greatest for the user. This is achieved, for example, in that the intensity of the tactile loading of the head by the tactile actuators of the group decreases with increasing distance of the point of intersection with the respective tactile actuator.

eingerichtet sein. Dabei ist I_i die Intensität des i-ten taktilen Aktors der aus z. B. drei oder mehr taktilen Aktoren gebildeten Gruppe mit i = 1, 2 und 3. v_i ist die Position des i-ten taktilen Aktors, die bspw. als Relativposition in Bezug auf die durch die drei taktilen Aktoren aufgespannten Trefferfläche angenommen werden kann. Mit hp wird der Schnittpunkt der vom Zielpunkt im dreidimensionalen Raum in der Umgebung des Benutzers zum Kopfmittelpunkt verlaufenden Geraden mit der durch die drei taktilen Aktoren aufgespannten Trefferfläche bezeichnet. Mit ep_i wird der Schnittpunkt einer zwischen dem Schnittpunkt hp und der Position v_i verlaufenden Geraden mit einer die beiden anderen taktilen Aktoren verbindenden Geraden bezeichnet. Mit dieser Beziehung lässt sich mit vertretbarem Rechenaufwand durch einen programmierten Mikrocontroller oder Mikroprozessor oder einer Hardwarelogik auf einfache und schnelle Weise ein Ansteuersignal für die taktilen Aktoren der Gruppe festlegen, mit dem die Intensität der taktilen Beaufschlagung des Kopfes des Benutzers auf zuverlässig und präzise erfassbare Zielpunkte hin ausgerichtet werden kann. The control unit can be used to control the tactile actuators with an intensity I _i according to the relationship

be furnished. In this case, I _{i is} the intensity of the ith tactile actuator of z. For example, three or more tactile actuators formed group with i = 1, 2 and 3. v _i is the position of the i-th tactile actuator, which can be assumed, for example, as a relative position with respect to the area defined by the three tactile actuators hit area. Hp is the point of intersection of the straight line running from the target point in the three-dimensional space in the user's environment to the head center point with the target surface spanned by the three tactile actuators. With ep _i of the intersection of a v _i extending between the intersection point HP and the position of the straight line is designated by a, the other two tactile actuators straight line connecting. With this relationship, a controlled signal for the tactile actuators of the group can be determined with a reasonable computational effort by a programmed microcontroller or microprocessor or a hardware logic, with the intensity of the tactile loading of the user's head on reliably and precisely detectable target points out can be aligned.

The control unit can be set up to control a tactile actuator arranged between the eyes on the nose of the user in such a way that the intensity of the tactile actuators adjacent to this tactile actuator is attenuated more strongly the closer a target is to this tactile actuator. With such an additional tactile actuator directly between the user's eyes, a definitive indication of the correct destination found by turning the user's head in the direction of the searched target point can optionally be communicated.

The invention will be explained in more detail with reference to an embodiment with the accompanying drawings. Show it:

1 - Sketch of a tactile display with distributed on three angularly aligned circular paths arranged tactile actuators;

2 - Sketch of the tactile display 1 looking at the back of the user's head;

3 - Sketch of a target area spanned by three adjacent tactile actuators with the intersection of a target point to the defined center of the head.

1 shows a sketch of a user's head H in the side view with a tactile display shown schematically by its essential components. The tactile display optionally has a visual display D (screen) for positioning in front of the user's eyes for three-dimensional display of images or videos and a plurality of tactile actuators T. These tactile actuators T are on three angularly offset from each other orbits K ₁ , K ₂ , K _{3 arranged} around the head H around. In this case, there is a tactile actuator T _K in the region of the chin of the head H. It can, for example, be held on a chin strap. The first circular path K ₁ runs around the forehead of the head H around. This first circular path K ₁ is aligned approximately horizontally (+/- 10 °) to the vertical axis of the head H. The further circular paths K ₂ and K ₃ are arranged at an angle of approximately 120 ° (+/- 20 °) to each other angularly offset.

It can be seen that a tactile actuator T is arranged on the third circular path K ₃ at the back of the head H in the neck area. It is also clear that in the area of the ears O no tactile actuator T is present. The tactile actuator T closest to an ear O is here at a distance of at least 4 cm, and preferably of more than 5 cm. This avoids that the auditory senses of the user are addressed by activation of the tactile actuators T.

The tactile actuators T and the display D are connected to a control unit S. This connection is illustrated by way of example only for some tactile actuators T, but is present in practice for all tactile actuators T of the tactile display.

The control unit S is set up to determine the intensity of the individual tactile actuators depending on the task of the tactile display and to control the tactile actuators such that they apply a haptic pressure signal or vibration signal to the head surface of the head H with the respectively defined intensity.

2 allows the rear view of the head H with the tactile display and his on the three circular paths K ₁ , K ₂ , K ₃ distributed tactile actuators T recognize. The tactile actuators T arranged on the front side of the head H, which is not actually visible, are also sketched here. In order to now point the user to an event in a target point in the three-dimensional circumference of the head H, the control unit S can simultaneously actuate a group of tactile actuators T selected as a function of the target point. The intensity of such a group of tactile actuators T is then selected so that the user receives as much as possible a haptic signal at the point of his head surface H, at which a straight line between the target point in the vicinity of the head H to the head center one by the group of tactile actuators T spans the stretched target area. If the user then turns his head H toward the target point, then this intersection changes, so that the control unit S adjusts the selection of the group of tactile actuators and the control of their intensity accordingly.

This will be explained with reference to an example with three tactile actuators T ₁ , T ₂ , T ₃ and an assumed target point Z in three-dimensional space around the head H. From the target point Z, an imaginary straight line G can be guided to a defined head center C. The defined head center C is z. B. as the focus of all tactile actuators T of the tactile display or as the common center of all circular paths K ₁ , K ₂ , K ₃ , ..., K _i known. Now forms a group of tactile actuators T ₁ , T ₂ , T ₃ a controlled by the control unit S group for haptic transmission of spatial information, which points to the destination Z. This group of tactile actuators T ₁ , T ₂ , T ₃ spans a hit area F, through which the straight line G runs. Thus, the tactile actuators T ₁ , T ₂ , T _{3 are} selected as a group between which the straight line G runs in each case for a target point Z relative to the defined center C of the head. The point of intersection hp of the straight line G between the target point Z and the defined center of the head C with the target surface F forms the decisive measure for controlling the individual tactile actuators T ₁ , T ₂ , T _{3 of} the selected group. The intensity of the individual tactile actuators T ₁ , T ₂ , T ₃ is determined as a function of the distance lib of the intersection point hp to the center of the respective tactile actuator T ₁ , T ₂ , T ₃ , with i = 1, 2, 3.

This is outlined for the first tactile actuator T ₁ as an example with the distance l _1b .

Furthermore, the intersection of the extension of the straight line between the intersection point hp and the center of the respective tactile actuator T ₁ , T ₂ , T ₃ is determined by the control unit S with a straight line connecting the other two tactile actuators T. For the first tactile actuator T ₁ then results in a distance l _1a between the intersection ep _{1 of} the straight line extension between the intersection hp and the center of the first tactile actuator T ₁ and the two other tactile actuators T ₂ , T ₃ connecting straight line.

For the other tactile actuators T ₂ , T ₃ can then in a corresponding way the Intersections ep ₂ , ep ₃ and the relevant lengths l _2a , l _{3a are} determined.

Likewise, for these tactile actuators T ₂ , T _{3, there is} a distance between the intersection point hp and the center of the respective tactile actuator T ₂ , T ₃ as l _2b and l _3b .

The centers of the respective actuators T ₁ , T ₂ , T ₃ are z. B. as three-dimensional vector coordinates (x, y, z) known. For each of the tactile actuators T ₁ , T ₂ , T ₃ applied to a target surface F, an intensity in the value range from 0 to 1 can now be determined. This can be done, for example, according to the relationship:

Now, if the relationship of Ti is mentioned, this is the three-dimensional vector coordinate of the center or center of gravity of the respective tactile actuator T ₁ , T ₂ , T ₃ . The index i designates the respective tactile actuator, which spans the hit area F with. The tactile actuators are then driven with the calculated intensities I _i in the range of 0-100%. With this interpolation, a smooth transition between the tactile actuators T ₁ , T ₂ , T ₃ and adjacent tactile actuators is ensured when the target point Z moves relative to the head position H.

In order to achieve a high final precision in search tasks without visual feedback, a tactile actuator T sitting directly on the nose between the eyes can be used with a slightly modified control. The closer the point of intersection hp comes to this tactile actuator T, the higher the intensity is selected for this tactile actuator T, while the other adjacent tactile actuators of the target surface F are attenuated. Thus, the signal of the arranged on the nose tactile actuator T comes out stronger. Namely, the user tries to maximize the signal of the tactile nose actuator T while the other two actuators T of the hit area F are turned off or almost stand still.

To increase the resolution in the forehead, it is advantageous to arrange two additional haptic tactile actuators T on the front ring K ₁ left and right of a frontal front actuator T.

The control unit S with its tactile display can be used for route guidance and navigation. This can also be done without visual representation purely by the sense of touch. The use of the additional visual channel with the help of the display D, however, is more precise and usually faster than the use of tactile and auditory sense. For complex situations, providing the additional haptic channel is often beneficial. The initial response times are often smaller for tactile feedback than for visual impressions. This is advantageous in order to give warning signals via the tactile actuators T or to draw attention to events outside the field of vision. With the help of the arranged over the multiple circular paths K ₁ , K ₂ , K ₃ tactile actuators T succeed over the entire three-dimensional space in the vicinity of the head H. This ensures a good coverage of almost all possible directions to a target point Z in three-dimensional space , The area of the ears O is kept free, wherein the tactile actuators are located a distance of at least 4-5 cm away from the ear canal.

As tactile actuators T are piezo actuators, inductively actuated actuators or vibration motors. These may be driven by a pulse width modulated signal to exert a tactile impression of a selected intensity on the user's head H.

In this case, a group of, for example, three tactile actuators T is selected, which are closest to the target point Z. The tactile actuator T lying closest to the target point Z can be activated with the highest intensity. The intensity of the tactile actuators T and the selection of a group of tactile actuators T depends on the position of the target point to the defined center of the head C and changes with a rotation of the head H. In particular, the user will usually always try his head towards to rotate the target point Z, so that the tactile signal along a trajectory in the direction of the head front side wanders. If the user optimally focuses the target point, then the straight line between the target point Z and the defined head center C usually runs through the root of the nose of the user. The tactile display can by suitable means of the control unit S z. B. be used by programming to direct the user's attention to selected targets Z in his environment. The control unit S can thus be used together with the tactile display for guidance to virtual or real objects in three-dimensional space. It is also conceivable, however, to make the impact of shockwaves, particles, virtual walls or borders as well as moving virtual objects on an area surrounding the head haptically palpable. The tactile display can also be used in conjunction with three-dimensional videos in the 360 ° space with haptic feedback.

The tactile display also allows precise guidance in three-dimensional space for blind people, the haptic messages of current or impending collisions in the virtual or real space, and in particular haptic feedback and attention to events outside the user's field of vision.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• GB 2522866 A [0005]

Cited non-patent literature

• M. Berning, F. Braun, T. Riedel, M. Beigl: Proximity Hat - A Head-Worn System for Subtle Sensory Augmentation with Tactile Stimulation, in: ISWC '15, September 7-11, 2015, Osaka, Japan, p. 31 to 38 [0004]
• MK Dobrzynski, S. Mejri, S. Wischmann, D. Floreano: Quantifying Information Transfer Through a Head-Attached Vibrotactile Display: Principles for Design and Control, in: IEEE Transactions on Biomedical Engineering, Vol. 7, July 2012, pages 2011 to 2018 [0006]

Claims (12)

Tactile display for carrying on the head (H) of a user with a plurality of tactile actuators (T) attachable to a headgear for placement on the head (H) of the user and connectable to a control unit (S), characterized in that the tactile actuators (T) are distributed over at least two circular paths (K ₁ , K ₂ , K ₃ ), the circular paths (K ₁ , K ₂ , K ₃ ) being aligned angularly offset from one another. Tactile display according to claim 1, characterized in that at least one tactile actuator (T) is provided on a chin strap for placement on the chin of the user. Tactile display according to claim 1 or 2, characterized in that at least one tactile actuator (T) is provided for placement on the neck of the user. Tactile display according to one of the preceding claims, characterized by a 3D screen designed for the arrangement in front of the eyes for the three-dimensional projection of images or videos. Tactile display according to one of the preceding claims, characterized in that the tactile actuators (T) are designed as piezo actuators or as inductively deflectable actuators. Tactile display according to one of the preceding claims, characterized in that adjacent to the ears (O) of the user no tactile actuators (T) are present. Tactile display according to one of the preceding claims, characterized in that the control unit (S) for the simultaneous activation of a group of adjacent tactile actuators (T) is set up. Tactile display according to claim 7, characterized in that the control unit (S) for controlling the group of adjacent tactile actuators (T) is set up such that the intensity of the actuation of the tactile actuators (T) of the group of at least one spatially in the group central tactile actuator (T ₁ , T ₂ , T ₃ ) to this at least one central tactile actuator (T ₁ , T ₂ , T ₃ ) surrounding other tactile actuators (T ₁ , T ₂ , T ₃ ) decreases towards. Tactile display according to claim 7 or 8, characterized in that the control unit (S) for controlling the tactile actuators (T) of a group as a function of the intersection of a target point (Z) in space to a defined head center (C) of the tactile Displays leading line (G) is set up with a hit area (F) spanned by the tactile actuators (T) of the group. Tactile display according to claim 9, characterized in that the control unit (S) for controlling the tactile actuators (T) with an intensity I _i according to the relationship:

is set up, where I _{i is} the intensity of the ith tactile actuator of the group with i =

{1, 2, 3, ...}, hp is the point of intersection of the straight line (G) running from the target point (Z) to the head center (C) with the plane spanned by the three tactile actuators (T ₁ , T ₂ , T ₃ ) ep _{i is} the intersection of a straight line (G) running between the intersection hp and the position v _{i of} the i th tactile actuator with a straight line (G) connecting the other two tactile actuators (T ₁ , T ₂ , T ₃ ), and v _{i is} the position of the ith tactile actuator. Tactile display according to one of the preceding claims, characterized in that the control unit (S) for controlling a on the user's nose between the eyes arranged tactile actuator (T) is set up such that the intensity of this tactile actuator (T) adjacent tactile Actuators (T) is the more attenuated the closer a target is to this tactile actuator (T). Method for controlling a tactile display according to one of the preceding claims, characterized by - determining an intersection point (hp) of a line (G) extending from a target point (Z) in space to a defined head center point (C) with one by three adjacent tactile actuators (T _1, T _2, T ₃₎ of the tactile display spanned target surface (F), and - setting the intensity of the tactile actuators (T _1, T _2, T ₃₎ in dependence on the distance of the intersection (hp) to the position of respective tactile actuator (T ₁ , T ₂ , T ₃ ).

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