Abstract:
The invention relates to a method and a device for generating a vibration pattern in a person, having a drive which sets a mass in rotation, and at least one sensor device which is coupled to a controller which controls the drive as a function of sensor data over the sensor device. The mass (m) is arranged in a homogeneously concentric fashion around its rotational axis ( 10 ), and an interface ( 20 ) transmits to the person reaction forces from the mass which arise owing to the change in the rotation.

Description:
TECHNICAL FIELD 
     The invention relates to a device and a method for generating a vibration pattern in a person, having a drive which sets a mass into rotation and at least one sensor apparatus that is coupled to a control which controls the drive dependent on sensor data from the sensor apparatus. 
     BACKGROUND 
     U.S. Pat. No. 5,413,611 describes a prosthesis with a feedback apparatus. Feedback relating to the applied force in a driven prosthesis is generated by a vibration generator. 
     US 2004/0178989 A1 describes a system and a method for providing haptic feedback, in which a motor with an eccentrically arranged mass is put into motion in order to generate a vibration pattern. A similar apparatus is described in WO 03/091984 A1. 
     SUMMARY 
     The object of the present invention is to provide a device for generating a vibration pattern and a method, in which complicated feedback patterns can easily be generated. According to the invention, this is achieved by a device with the features of the main claim and by a method with the features of the coordinate claim. Advantageous embodiments and developments of the invention are listed in the dependent claims. 
     The device according to the invention for generating a vibration pattern in a person, having a drive which sets a mass into rotation and at least one sensor apparatus that is coupled to a control which controls the drive dependent on sensor data from the sensor apparatus, provides for the mass to be arranged in a concentric homogeneous fashion about the rotational axis thereof and for the device to have an interface which transmits the reaction forces to the patient from the mass, which arise as a result of the change in the rotation. The device has a homogeneous concentric mass which is set into rotation by a drive. Here, the generation of the vibration pattern is based on the action/reaction principle. A directed inertia force arises as the result of the acceleration of the rotating mass and initiates a counter movement in a stator about which the concentric mass rotates. The reaction force arising thus generates feedback that can be felt by the user. 
     The rotating mass is preferably embodied as a rotor which is mounted about a stator of the drive such that the device can be embodied to have a very small design. 
     The sensor apparatus, which supplies the data on the basis of which the control unit calculates the required magnitude of the swept-through rotor angle, the angular velocity and the acceleration, can be embodied as a pressure sensor, position sensor, torque sensor, movement sensor and/or temperature sensor. As a result, it is possible to record a multiplicity of influences and transmit them to the user of the device by means of a vibration pattern. 
     By way of example, the sensor apparatus, like the vibration apparatus, can be arranged in or on an exoprosthesis or coupled to an exoprosthesis. Thus, for example, it is possible to process states of the prosthesis elements within the exoprosthesis and, via the device, transmit them to the stump or the attachment point of the prosthesis on the body. Alternative attachment positions of the device are likewise available; in principle, all sufficiently sensitive body points are suitable for this. 
     An attachment arrangement for attaching the device to the person can be arranged on the device. The attachment arrangement can be embodied as a belt, cuff, or clasp. The vibration pattern may likewise be transmitted to the body by means of a coupling element. The coupling element can concentrate the vibration, for example by coupling the stator to the user of the device by means of an extension or an apparatus with a bearing face that is smaller than the stator. The coupling element, which transmits the reaction forces to the person from the mass, may be arranged in a detachable fashion on the device or be an integral part of the device. To the extent that the coupling element is connected to a stator of the drive via a lever, there can be an adapted vibration transmission. A lever arrangement can likewise make it possible to implement a geared transmission, by means of which the amplitude is increased. 
     The method according to the invention for generating a feedback signal, in which a sensor signal is provided by at least one sensor apparatus and a mass, arranged concentrically and homogeneously about a rotational axis, is driven depending on the sensor signal, provides for a frequency- and/or amplitude-modulated feedback pattern to be generated. Here, the mass is driven in different rotational directions and with different angular velocities, depending on the sensor signal and, corresponding to this, the feedback pattern to be generated. The mass for generating the feedback pattern is driven with different acceleration patterns depending on the sensor signal, wherein the acceleration patterns can be varied both in terms of a frequency modulation and in terms of an amplitude modulation. The amplitude modulation is regulated by the acceleration of the rotor. The acceleration is regulated on the basis of measured movement variables of the rotor; the greater the rotor acceleration, the higher the amplitude of the stimulation. The frequency is a function of the angular velocity and the swept-through rotor angle. By synchronizing the angular velocity and the swept-through rotor angles, it is possible to modulate the frequency of the stimulation as desired. Here, the frequency may be constant or variable. 
     It is possible for the signal to be generated in a time-dependent fashion or dependent on a state of the device or the attachment parts thereof. The device can be triggered by specific states of, e.g., the prosthesis. By way of example, an automatic switchover of the prosthesis into another mode can lead to the information in relation to a different prosthesis behavior being transmitted to the wearer of the prosthesis using an appropriate signal. It is likewise possible to indicate specific states, e.g. a charge state of a rechargeable battery, a switched-on prosthesis state or prosthesis components overheating, by a corresponding vibration pattern. 
     In principle, it is also possible to connect the device to a prosthesis by means of a cable or a radio link. As a result, it is possible to transmit states that are established within a prosthesis to a distant point by means of a vibration pattern. Here, the application of the device is not restricted to transmitting data relating to a prosthesis. It is likewise possible to obtain feedback from exercise equipment or else obtain feedback from myoelectric signals, which were captured by appropriate leads. 
     In the following text, exemplary embodiments of the invention will be explained in more detail using the attached figures, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an illustration of the functionality of the device; 
         FIG. 2  shows a perspective view or a vibration generator; 
         FIG. 3  shows a sectional view; 
         FIG. 4  shows a schematic illustration of a device; 
         FIG. 5  shows an illustration of an applied device; 
         FIG. 6  shows different arrangements on a person; and 
         FIG. 7  shows illustrations of frequency modulations and amplitude modulations. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates the basic design of a device for generating a vibration pattern as per the present invention. The device has a homogeneous/concentric mass m which is rotated, by an electric drive (not illustrated) with a swept-through rotor angle Δθ 9 , the angular velocity ω and the acceleration a=dω/dt. The swept-through rotor angle Δθ and the angular velocity ω are either measured directly by sensors or established indirectly by converting the rotor movement variables. The established rotor position and the current angular velocity are used by a motor control unit  5  (see  FIG. 4 ) for generating predetermined vibration patterns on the basis of sensor data that are provided by a sensor apparatus which does not establish the rotor movements. Thus, this is an apparatus for transmitting feedback by means of vibration patterns, wherein the feedback is generated on the action/reaction principle. A directed inertia force Fa arises according to the formula Fa=m*a as a result of accelerating the rotating mass m. This directed inertia force Fa initiates a counter movement in the stator  15  of the motor. The reaction force arising thereby generates an impulse that can be felt by the user and hence it generates feedback. 
     In a perspective illustration of an embodiment in  FIG. 2 , the rotating mass m is provided in the form of a ring which is arranged in a concentric and homogenous fashion about the rotational axis  10 . The rotational axis  10  is situated in the center of a stator  15 , which is embodied as a stator of a motor. Thus, the mass m is part of the drive, namely part of an electric motor. In addition to the illustrated integrated solution, in which the mass m is not mounted separately, there is the option of coupling the drive to the rotatably mounted mass m by means of a gearing mechanism or a transmission. Around the stator  15 , the moveable rotor is arranged as a rotating mass m, and so the design here is that of an external-rotor electric motor. In the embodiment as an electronically commutated direct-current motor, the rotating mass m can consist of annularly arranged permanent magnets, or it can have the latter, in order to generate the rotation of the rotating mass m. As a result of an appropriate control of the exciter coils within the stator  15 , it is possible to generate a vibration pattern as a feedback pattern in amplitude modulated and/or frequency modulated fashion. Additionally, this affords the possibility of superposing a plurality of modulated feedback patterns and thus of generating a large variety of very complicated feedback patterns, and so a multiplicity of sensor data of very different types can be transmitted to the user of the device  100  in a simple and reliable fashion using feedback patterns of very different types. 
     The amplitude modulation is regulated by the acceleration of the rotor m. If the rotating mass m is already rotating, the current state is captured by the motor control unit  5  (see  FIG. 4 ). The acceleration is then regulated on the basis of the measured or established movement variables of the rotating mass m such that the directed inertia force Fa is generated as a result of the change in the angular velocity, which inertia force can be transmitted to the user of the device  100  via the stator  15 . Within the meaning of both a positive and a negative acceleration, the greater the acceleration of the rotating mass m, the greater the amplitude of the stimulation and the vibration amplitude. If the mass m is initially at rest, the corresponding vibration effect is achieved by acceleration in the one and/or other direction. 
     The frequency of the generated vibration is a function of the angular velocity ω and the swept-through rotor angle Δθ. By synchronizing the angular velocity ω and the swept-through rotor angles Δθ, it is possible to modulate the frequency of the stimulation as desired. Here, the frequency may either be constant or variable. The frequency of the stimulation emerges from the ratio of the angular velocity ω to the swept-through rotor angle Δθ. 
       FIG. 4  shows the device  100  in an enlarged and schematic fashion. Here, the device  100  is arranged on the skin surface  30  of a user. The rotating mass m rotates about the rotational axis  10 , around which the stator  15  is arranged. In the illustrated exemplary embodiment, the device  100  provides for the mass m to be part of the drive, namely part of the electric motor made of the stator  15  and the rotor that forms the mass m. The stator  15  of the motor generates a rotating magnetic field, as a result of which the rotating mass m is rotated depending on the type of rotating field. Here, the stator  15  is fixed to a housing  20  which forms the interface between the device  100  and the skin surface  30 . An appropriate pattern of reaction forces and hence of vibrations is generated depending on rotational direction, frequency and amplitude of the change. 
     Here,  FIG. 5  shows the device  100  in the applied state. In  FIG. 5 , the device  100  has been applied to an upper part of the arm by means of an attachment arrangement  40  in the form of a cuff.  FIG. 5  also shows the acting torques about a rotation axis X of the mass m. The rotation axis X is shown in  FIG. 5  arranged substantially perpendicular to the attachment arrangement  40  and to a skin surface  30  of the body part (i.e., upper arm) to which the device  100  is mounted. The reaction torque Mr is exerted on the interface, i.e. the housing  20 , by the rotating mass m. The magnitude of the torque Mr is defined by the moment of inertia of the rotating, homogeneous concentric mass m and the force or acceleration acting thereon. 
       FIG. 6  shows different attachment points of the device  100 , for example on the wrist, on the chest, on the upper part of the arm, on the forearm or on the thigh. It is likewise possible to arrange the device directly in a prosthesis apparatus  50 ,  60 , for example in a forearm prosthesis  50  or in a thigh shaft  60  of a leg prosthesis. 
       FIG. 7  illustrates a frequency modulation and an amplitude modulation. In the case of a stepwise acceleration a with an unchanging magnitude there is no change in the strength of the vibration impulse; since, over time, the acceleration or deceleration or movement reversal occurs at ever shorter time intervals, the vibration frequency increases such that the user of the device obtains feedback which is generated depending on the measured sensor signals. The positive and negative acceleration a either means that the rotational direction is reversed or that the mass is accelerated and decelerated about a basic velocity. 
     By contrast, the right-hand illustration of  FIG. 7  shows an amplitude modulation in which the measure of the acceleration a is varied without changing the frequency. In the illustrated exemplary embodiment, this initially leads to a weak vibration being transmitted to the user, which vibration increases over time until it decreases again after reaching the maximum. By superposing the frequency modulation and the amplitude modulation, it is possible to generate multifaceted signal patterns and transmit these to the user of the device. 
     In addition to data, e.g. in respect of the state of a prosthesis apparatus  50 ,  60 , for example the current grip force, it is possible to transmit other data to the user via the device  100 , for example state data relating to temperature, switch-on states, operating modes, battery states or the like. It is likewise possible to process myoelectric data, recorded by leads, and transmit these on to the user as vibration signals, for example to be able to carry out optimized training.