Haptic feedback device and procedures for operating the device

Abstract

Method for operating a haptic feedback device for persons to perceive the environment as an orientation aid and to direct attention to dangerous situations by means of haptic information elements and to trigger a tactile stimulus in conjunction with shape memory elements (4) characterized by that in a first process step, at least one shape memory actuator (2, 12) in conjunction with a tactile information element (3, 13, 14, 15) and in conjunction with at least one shape memory element (4) designed as an actuating element causes the corresponding shape memory actuator (2, 12) to perform a linear movement of the respective tactile information element (3, 13, 14, 15) by heating it, to press against a contact point of a user or at a human-machine interface to trigger the tactile stimulus, and that in further process steps, the actuation speed of the tactile information elements (3, 13, 14, 15) is adjusted to haptic information, the penetration depth of the tactile information element(s) (3, 13, 14, 15) is continuously changed depending on the haptic information, and the position and / or force of the pressure of the tactile information elements (3, 13, 14, 15) on the contact point of a person or at the human-machine interface is measured when the tactile stimulus is triggered by a sensor or by a change in the intrinsic resistance of the shape memory element (4) during the crystalline transformation takes place. that in order to achieve a combination of tactile and vibrotactile information, the movement of the shape memory element (4) is superimposed by at least one further movement of the shape memory element (4), and the further movement takes the form of a linear movement offset by 90° or an oscillating movement, or that by combining an penetrating movement with a second movement to change the position of the corresponding tactile information element (3,13,14,15) on the skin, an alternating movement of tactile information elements (3,13,14,15) and elements within an array takes place. and that in a final process step, when the shape memory element (4) cools down, the tactile information elements (3, 13, 14, 15) are returned to their initial position.

Description

[0001] The invention relates to a method and a device for haptic information acquisition and warning of persons for the perception of the environment as orientation support and for directing attention to dangerous situations by means of haptic information elements, which are in a compact device for attachment both to body parts of the human body as well as in handrails of walkers, shopping carts or other human-machine interfaces and can be used in indoor or outdoor areas.

[0002] Haptic information systems, which help blind people participate in everyday life, are particularly well-known in the field of technology. Nowadays and in the future, the operation of machines and the flow of information between humans and machines are becoming increasingly complex, pushing the use of conventional human-machine interfaces and visual or auditory information transmission to their limits. Haptic information systems thus represent a viable alternative. Furthermore, older people often experience a significant decline in their visual and auditory perception. However, in contrast to sight and hearing, the ability to perceive sensory signals through haptic perception does not diminish even in old age. The human haptic perception system reacts to how firmly and quickly an object is pressed into the skin.Both stimuli overlap and are perceived as a single haptic event. The term "haptic perception" encompasses all aspects of touch, especially the use of the hands. The perception of the environment through the sense of touch can be differentiated into tactile and kinesthetic stimuli. Tactile stimuli provide information about pressure, temperature, pain, or vibration, while kinesthetic stimuli detect parameters such as joint angle or muscle tension. Tactile perception occurs through receptors on or in the skin. These tactile stimuli are necessary, for example, for controlling fine motor interactions. Kinesthetic perception occurs with the help of receptors in the joints, muscles, and tendons. These receptors make it possible to detect the position and movement of the limbs, as well as the forces exerted in the muscles.Besides cognitive load and attention, the spatial and temporal sensitivity of the sense of touch primarily determines its limitations. The limited memory span also plays a role in the assessment of information perceived through the skin. However, with appropriate presentation, large amounts of information can be perceived via the skin's surface. Current haptic information systems typically use the rotation of asymmetrical components driven by an electric motor, resulting in vibration of the entire system. In addition to the intensity, the vibration frequency can be changed, and frequency patterns can be transmitted. These systems are now found in every smartphone as vibration alerts.Vibration actuators are also known to be used to transmit aircraft status information to the pilot, and the German Society for Aeronautics and Astronautics (DGfA) is using them to develop a vibration hand sensor for flight control. Commercial developments utilize multiple vibration actuators connected to a smartphone and integrated into a belt for navigation by visually impaired individuals.From DE 10 2010 032 706 B4, a vibrotactile feedback device for attachment to parts of the human body is known, comprising a ring-shaped mounting device with several feedback modules attached to the mounting device and electrically connected to one another. The mounting has at least two elastic stretchable bands that connect a portion of the intermediate elements arranged between the feedback modules and the feedback modules themselves to adapt to different parts of the human body. Furthermore, permanently installed vibration actuators in bicycles are known and are, for example, installed in bicycle handlebars and used for navigation in cities.From DE 20 2015 102 562 U1, a navigation device with a navigation grip for a two-wheeler for mounting in a handlebar tube is known, wherein at least one communication device is provided for generating a haptic and / or acoustic ad-hoc navigation instruction for perception by a human user. From DE 10 2016 001 553 A1, a driver assistance system with a device for outputting a warning signal in a vehicle is further known, wherein, for the output of a warning signal in a dangerous situation, a driver's seat belt, a seat backrest, or at least a driver's seat is designed such that the warning signal can be automatically output as a vibrotactile and location-congruent warning signal.From DE 200 80 209 U1, a control of haptic sensations for an interface device with vibrotactile feedback is also known, and in DE 10 2014 105 538 A1, a haptic system with a haptic device and a method for operating a haptic system is described, wherein the haptic device has an end effector connection and a gear structure with which a translational movement can be generated as an output variable, which is guided via a cantilever from the gear structure to the end effector connection in order to move it perceptibly for a user.

[0003] From US patent 2013 / 0 154 984 A1, a haptic system integrated into a display and control unit of a smartphone is known. This system, when touched by an operator's finger, triggers a click sensation based on the contraction and extension action of a wire-shaped shape-memory alloy, enabling the operator to operate the device. From GB patent 2 510 147 A, haptic feedback actuators are further known, comprising a haptic feedback actuator consisting of a user contact element in a holder, a shape-memory alloy, a power receiving and power transmission circuit for transferring electrical energy to the user contact element, and a method for simulating an object in a virtual reality system using RFID tags.US Patent 2012 / 0 212 442 A1 describes a device for transmitting tactile information to a living being by touching a shape memory alloy, in which a transparent, sheet-like, tactile sensor unit arranged on a display field is provided and a signal generation unit that generates a signal voltage to control the tactile sensor unit, wherein the shape memory alloy arranged on the tactile sensor unit transmits the information to the living being.From US 2009 / 0 130 639 A1, a tactile display for transmitting colors by means of an arrangement of pins and a method for displaying an image on a tactile display are also known, as well as from US 2014 / 0 202 843 A1, a touch field device with a force feedback function in the form of a force feedback type, which provides a tactile feeling to an operator by vibrating a touch surface, so that the operator can prevent breakage or damage to the touch field when an external shock occurs to the touch panel.

[0004] Haptic feedback devices driven by a shape memory element are known from publications of the IEEE International Conference on Robotics and Automation Orlando, Florida 2006, such as a spiral shape memory alloy as a pin-rod actuator for determining visual depth information, a tactile display device for the blind for tactile perception with tactile pins actuated by shape memory alloys, a microtactile display device for representing human soft tissue comprising an eddy current sensor for force measurement, with a display pin supported by shape memory springs, an innovative tactile display device based on electroactive polymer (EAP) soft actuator technology that can be used as a portable tactile display, a Braille display for the visually impaired, and a human interface, and a tactile display device consisting of a thick-film array,a photolithographed micromechanism with a preload spring, a micropin and a cap assembly.

[0005] One disadvantage of the previously known state of the art is that, after contact, often only slowly adapting skin receptors remain active after a few hundred milliseconds, and the quality of the sensation changes noticeably.

[0006] Based on this prior art, the invention aims to create a haptic feedback device and a method for operating the haptic feedback device, with which information intake is increased by changing the tactile stimulus. In order to achieve a permanent change in the stimulation parameters, the tactile element should be able to change its penetration depth and / or position and / or allow combination with vibrotactile stimuli.

[0007] To solve this problem, the present invention proposes a method with the features of claim 1 and a haptic feedback device with the features of claim 5.

[0008] The inventive method for operating the haptic feedback device for persons to perceive the environment as orientation support and to direct attention to dangerous situations by means of haptic information elements, as well as for triggering a tactile stimulus in conjunction with shape memory elements, comprises several process steps, wherein in a first process step, at least one shape memory actuator in conjunction with a tactile information element and at least one shape memory element designed as an actuating element causes the corresponding shape memory actuator to perform a linear movement of the respective tactile information element by heating it, in order to press against a contact point of a user or at a human-machine interface to trigger a tactile stimulus. and in further process steps, an adjustment of the positioning speed of the tactile information elements to the haptic information, a stepless change of the penetration depth of the tactile information element(s) depending on the haptic information, a measurement of the position and / or force of the pressure of the tactile information elements on a contact point of a person or at a human-machine interface when a tactile stimulus is triggered, a force measurement by means of a sensor or by a change in the intrinsic resistance of the shape memory element during the crystalline transformation takes place, wherein, in order to achieve a combination of tactile and vibrotactile information, the movement of the shape memory element is superimposed by at least one further movement of the shape memory element, and the further movement takes the form of a linear movement offset by 90° or an oscillating movement, or by combining the penetrating movement with a second movement to change the position of the corresponding tactile information element on the skin, an alternating movement of tactile information elements and elements within an array takes place, and in a final process step, when the shape memory element cools down, the tactile information elements are returned to their initial position.

[0009] The method according to the invention has the advantage that the movement of the shape memory element is continuously controllable depending on the haptic information, so that the intensity of the tactile stimulus can be adjusted via the penetration depth of the tactile information elements, whereby information about the distance to an obstacle or hazard can be continuously transmitted, and the actuation speed of the shape memory element is provided to be adaptable to the haptic information. Because the movement of the shape memory element is continuously controllable, a tactile stimulus can assume not only two states, but the intensity of the stimulus can be adjusted via the penetration depth of the tactile information element. Information, for example about the distance to an obstacle or hazard, can thus be transmitted continuously. The actuation speed is adaptable to the haptic information.

[0010] The movement of the tactile information elements does not occur simultaneously, but rather in response to the tactile stimulus, with the information elements being switchable in a defined sequence. The depth to which a person should react to the haptic information, or how far they have progressed towards their goal, can be represented by the depth to which the actuator penetrates the skin. The applications are not limited to supporting the elderly. In addition to acoustic and visual devices, haptic systems are also available for information transmission.

[0011] A further advantage is seen in the fact that the movement of the shape memory element is superimposed by at least one further movement, wherein the further movement represents an offset linear movement or an oscillating movement, so that the oscillating movement provides a combination of tactile and vibrotactile information, and wherein the further movement is provided by means of a second shape memory element or a piezo drive or an electrodynamic drive and corresponding transmission elements.

[0012] The information elements based on shape memory alloys primarily serve to implement purely tactile actuators. Shape memory actuators operate silently, so stimuli are transmitted solely via the haptic channel. A clear separation from acoustic stimuli is thus possible. This represents a significant innovation in tactile information elements. An extension of the invention is the combination of a tactile shape memory actuator and a vibrotactile actuator. The vibrotactile actuator can be implemented with both conventional drives and shape memory elements. Standardized shape memory actuators are advantageously provided for the haptic feedback device, and these can be used in varying numbers within the device.

[0013] The device according to the invention for carrying out the method for haptic information acquisition and for warning persons, for attachment to human body contact points as well as in or on human-machine interfaces, consists in an advantageous embodiment of a housing in which at least one shape memory actuator with tactile information elements is arranged in conjunction with a shape memory element as an actuating element.wherein, upon heating of the shape memory element, the shape memory actuator causes a linear movement of the respective tactile information element to press against a contact point of a user or at a human-machine interface to trigger a tactile stimulus, and upon cooling of the shape memory element, a return of the tactile information element is provided, and wherein the shape memory actuator is provided by means of fastening means directly at human body contact points as well as in or at human-machine interfaces.

[0014] According to the invention, the device for haptic information acquisition and warning of persons uses haptic information elements, implemented as compact actuators based on shape memory alloys, to facilitate environmental perception, orientation support, and attention to hazardous situations. In contrast to conventional drive principles, the use of actuators with shape memory alloy actuators allows for the production of simple and silent actuators. Furthermore, shape memory alloys are characterized by a high power density. This means that relatively high forces can be achieved with small material cross-sections or quantities. Advantageously, the shape memory elements enable the realization of various types of movement and offer considerable freedom in their design.

[0015] Another advantage is that the device can be attached to specific body parts using straps or cuffs, similar to a watch strap or the wrist cuff of a blood pressure monitor. Alternatively, the actuators can be integrated into the handles of machines, devices, vehicles, or other human-machine interfaces. A component of the device presses against the skin at a specific point that has been found to be comfortable and easily perceived by humans. This arrangement allows for the use of large tactile information elements, making the shape-memory-based actuators suitable for a wide range of users. Integration into the handles of walkers, shopping carts, and similar devices is also planned.Potential applications for haptic feedback on rollators include outdoor navigation and the display of warnings, such as warnings about black ice or red traffic lights. Indoors, navigation can be used in hospitals and nursing homes. In shopping centers, haptic feedback on shopping carts can help locate products or efficiently manage shopping lists. In industrial settings, haptic feedback can be used, for example, in handheld control units for cranes and similar equipment. This allows information about distances between loads and supports, or even the start of force application during lifting, to be transmitted. Depending on the application, haptic feedback devices permanently mounted on the user or on the equipment may be preferable.

[0016] It is advantageous that the shape memory element is heated by means of a direct current supply via electrical conductors coupled to the shape memory element, wherein either a second shape memory element is provided to return the shape memory element to its initial position in conjunction with the tactile information elements after heating, or the tactile information elements have return springs for the return movement of the shape memory element.

[0017] A preferred embodiment involves the tactile information elements having different geometries or surface sizes depending on the point of contact with the skin, so that the contact area of ​​the tactile information elements can be adapted to the application or the individual. For non-fixed haptic devices, larger surfaces that can contact the skin have proven more suitable, as this accommodates any hand size. The tactile information element that touches the hand is made of a material adapted to the needs of the application.

[0018] Furthermore, to protect against overload, the shape memory element of the device is coupled to a protective spring at one end. An advantageous further development is seen in the provision of several tactile information elements for area-based stimuli, wherein the tactile information elements perform a linear movement when heated by the application of an electrical conductor via at least one shape memory element.

[0019] A preferred embodiment of the device is characterized by a housing designed so that the haptic feedback device fits snugly against a person's body or can be integrated, for example, into various handles for walkers or shopping carts. The shape memory element is essentially arc-shaped. To measure the force exerted by the tactile information elements on a person's contact point, the device either incorporates a sensor or the force measurement is achieved by detecting changes in the shape memory element's intrinsic resistance during crystalline transformation.

[0020] Another preferred embodiment of the device is seen in that the shape memory element is designed in a wire-like form, wherein the diameter of the shape memory element is designed depending on the moving force and the length of the shape memory element is designed depending on the positioning distance.

[0021] Furthermore, it is provided that the device has standardized shape memory actuators in varying numbers in the housing, whereby either a second shape memory element or a piezo drive or an electrodynamic drive with corresponding transmission elements is provided to execute multiple movements of the shape memory element.

[0022] By using shape memory elements, a slow-switching device can be implemented, and a warning signal is retained even after deactivation of the electrical signal due to the inertia of the shape memory elements.

[0023] The invention is explained in more detail below with reference to exemplary embodiments shown schematically in drawings.

[0024] This shows: Fig. 1: A first embodiment of a haptic feedback device based on a shape memory actuator in section; Fig. 2: the first embodiment in isometric view; Fig. 3: a second embodiment of a haptic feedback device based on a shape memory actuator in a half-view isometric view; Fig. 4: the second embodiment in section; Fig. 5: a standardized shape memory actuator in isometric view.

[0025] In the Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. Section 5 presents two exemplary implementations of haptic feedback devices based on shape memory actuators. Shape memory-based haptic information and warning systems operate silently, so that stimuli are transmitted only via the pure haptic channel, thus enabling a clear separation from acoustic stimuli.

[0026] In a first embodiment according to the Fig. 1 and Fig. The haptic feedback device 2 is constructed as an arc-shaped shape memory actuator 2 and consists of a housing 1, a tactile information element 3, and a shape memory element 4. The tactile information element 3 has different sizes and shapes depending on its point of contact with the skin and the area of ​​application. For non-fixed, shape memory-based haptic feedback devices, larger surfaces that can contact the skin have proven suitable, as they accommodate all hand sizes. The diameter of the shape memory element 4 depends on the force to be generated, and its length depends on the required travel distance. Travel distances between 3 and 6 mm are required. The shape memory element 4 moves the tactile information element 3, thereby applying pressure to the skin.The mechanical arc shape of the shape memory element 4 is used to translate the strain when generating the maximum system force. The shape memory element 4 is heated by direct current application via the electrical conductors 5 and 6 connected to it. To ensure that the shape memory element 4 returns to its initial position when the current required for heating is switched off, the shape memory actuator 2 requires a restoring mechanism. This can be achieved either by a second shape memory element (not shown) or, as in the illustrated embodiment, by the two restoring springs 7 and 8. The restoring springs 7 and 8 are coupled to the shape memory element 4. The linear guidance of the tactile information element 3 is provided by two guide columns 9 and 10 arranged in the housing 1 and connected to the tactile information element 3.In situations where the force would cause the shape memory element 4 to tear, overload protection is provided in the form of a protective spring 11 coupled to the shape memory element 4. It is connected in series with the shape memory element 4. The speed at which the tactile information element 3 extends is determined by the current. The current must remain below the maximum value at which the shape memory element 4 is destroyed. The retraction process depends on the cooling rate of the shape memory element 4 and the spring constant of the return springs 7 and 8, with the cooling rate being the dominant factor. The shape memory element 4 is preferably provided with crimps at both ends, which serve, firstly, to attach the electrical conductors 5 and 6 to the housing 1 and to the protective spring 11, and secondly, to make contact with the electrical conductors 5 and 6.A sensor that measures the force with which the tactile information element 3 presses against the skin is not shown in the exemplary embodiment. However, such a sensor can also be implemented using conventional measuring principles via the electrical intrinsic resistance of the shape memory element 4.

[0027] The Fig. 3 and Fig. Figure 4 shows a second embodiment in which several shape memory actuators 12 are arranged to move the tactile information elements 13, 14, 15. The shape memory actuators 12 are arranged accordingly. Fig.The shape memory actuators 12 are designed as standard and can be installed in varying numbers in the housing 1. In the present embodiment, three shape memory actuators 12 are arranged. Shape memory elements 4 are arranged in the shape memory actuators 12. When these elements heat up, they move the tactile information elements 13, 14, 15 outwards via the electrical conductors 5, 6, pressing them against the skin. The shape memory elements 4, and thus the tactile information elements 13, 14, 15, are returned to their original position by the return springs 7. A protective spring 11 is also provided as overload protection. However, a more complex control system is necessary when multiple shape memory actuators 12 are used. Reference symbol list 1 case 2. Shape memory actuator 3 tactile information element 4. Shape memory element 5 electrical conductors 6 electrical conductors 7 Return spring 8 Return spring 9 Leadership Pillar 10 Leadership Pillar 11 Protective spring 12. Shape memory actuator 13 tactile information element 14 tactile information element 15 tactile information element

Claims

Method for operating a haptic feedback device for persons to perceive the environment as orientation support and to direct attention to dangerous situations by means of haptic information elements and for triggering a tactile stimulus in conjunction with shape memory elements (4) characterized in that in a first method step, at least one shape memory actuator (2, 12) in conjunction with a tactile information element (3, 13, 14, 15) and in conjunction with at least one shape memory element (4) designed as an actuating element causes the corresponding shape memory actuator (2, 12) to perform a linear movement of the respective tactile information element (3, 13, 14, 15) by heating the latter, to press against a contact point of a user or at a human-machine interface to trigger the tactile stimulus, and that in further method steps the actuating speed of the tactile information elements (3, 13, 14, 15) is adjusted.13, 14, 15) to a haptic information, a stepless change in the penetration depth of the tactile information element(s) (3, 13, 14, 15) depending on the haptic information, a measurement of the position and / or force of the pressure of the tactile information elements (3, 13, 14, 15) on the contact point of a person or at the human-machine interface when the tactile stimulus is triggered by a sensor or by a change in the intrinsic resistance of the shape memory element (4) during the crystalline transformation, that to achieve a combination of tactile and vibrotactile information, the movement of the shape memory element (4) is superimposed by at least one further movement of the shape memory element (4), and the further movement takes the form of a linear movement offset by 90° or an oscillating movement,or that by combining a penetration movement with a second movement to change the position of the corresponding tactile information element (3, 13, 14, 15) on the skin, an alternating movement of tactile information elements (3, 13, 14, 15) and elements within an array takes place, and that in a final process step, when the shape memory element (4) cools down, the tactile information elements (3, 13, 14, 15) are returned to their initial position. Method for operating the haptic feedback device according to claim 1, characterized in that a further movement of the tactile information elements (3, 13, 14, 15) is carried out by means of a second shape memory element or a piezo drive or an electrodynamic drive by means of corresponding transmission elements. Method for operating the haptic feedback device according to claims 1 and 2, characterized in that information about a distance to an obstacle or a danger point is continuously transmitted and the positioning speed of the shape memory element (4) is adapted to the haptic information. Method for operating the haptic feedback device according to one of claims 1 to 3, characterized in that the movement of the tactile information elements (3, 13, 14, 15) does not occur simultaneously, but rather depending on the tactile stimulus for switching the tactile information elements (3, 13, 14, 15) in a defined sequence. Haptic feedback device for carrying out the method according to claims 1 to 4 for attachment to human body contact points as well as in or on human-machine interfaces, characterized in that the haptic feedback device consists of a housing (1) in which at least one shape memory actuator (2, 12) with tactile information elements (3, 13, 14, 15) is arranged in conjunction with a shape memory element (4) as an actuating element, wherein the shape memory actuator (2, 12) upon heating of the shape memory element (4) performs a linear movement of the respective tactile information element (3, 13, 14, 15) to press against a contact point of a user or on a human-machine interface to trigger a tactile stimulus, and upon cooling of the shape memory element (4) a return of the tactile information element (3, 13, 14, 15) is provided, wherein the shape memory actuator (2,12) is provided by means of fastening devices directly at points of contact with the human body as well as in or at human-machine interfaces. Haptic feedback device according to claim 5, characterized in that the shape memory element (4) is heated by means of a direct current supply via electrical conductors (5, 6) coupled to the shape memory element (4), wherein either a second shape memory element is provided to return the shape memory element (4) in conjunction with the tactile information elements (3, 13, 14, 15) to its initial position after heating, or the tactile information elements (3, 13, 14, 15) have return springs (7, 8) to move the shape memory element (4) back. Haptic feedback device according to claims 5 and 6, characterized in that the tactile information elements (3, 13, 14, 15) have different geometries and surface sizes, so that a pressure surface of the tactile information elements (3, 13, 14, 15) can be adapted to the application or the person. Haptic feedback device according to one of claims 5 to 7, characterized in that, to protect against overload, the shape memory element (4) is coupled at one end to a protective spring (11). Haptic feedback device according to one of claims 5 to 8, characterized in that several tactile information elements (3, 13, 14, 15) are provided for area-based stimuli, wherein the tactile information elements (3, 13, 14, 15) perform a linear movement by means of at least one shape memory element (4) when the shape memory element (4) is heated by current supplied via electrical conductors (5, 6). Haptic feedback device according to one of claims 5 to 9, characterized in that the shape memory element (4) is essentially arc-shaped, wherein a sensor for measuring the force of the pressure of the tactile information elements (3, 13, 14, 15) on a contact point of the person is arranged or the force measurement is provided by the change in the intrinsic resistance of the shape memory element (4) during the crystalline transformation. Haptic feedback device according to one of claims 5 to 10, characterized in that the shape memory element (4) is wire-shaped, wherein the diameter of the shape memory element (4) is dependent on the moving force and the length of the shape memory element (4) is dependent on the positioning distance. Haptic feedback device according to one of claims 5 to 11, characterized in that the device has standardized shape memory actuators (2, 12) in different numbers in the housing (1), wherein either a second shape memory element or a piezo drive or an electrodynamic drive with corresponding transmission elements is provided to execute several movements of the shape memory element (4).

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