Abstract:
A robotic endoscopy actuator is provided. The robotic endoscopy actuator includes a function means; and an energy absorption element that is operable to absorb energy from an electromagnetic field. The energy absorption element includes a heat element. The function means is operable to fulfill a function using heat energy.

Description:
[0001]    The present patent document claims the benefit of the filing date of DE 10 2006 019 419.5, filed Apr. 26, 2006, which is hereby incorporated by reference. 
       BACKGROUND 
       [0002]    The present embodiments relate to a robotic endoscopy actuator, for example, an endorobot actuator. 
         [0003]    Conventional endoscopy uses an elongated endoscopic device for insertion into the organ or vessel for diagnosis of diseases. DE 10 2005 006 877 A1 discloses a capsule endoscopy that may also be used for the diagnosis of diseases, such as diseases of the gastrointestinal tract. During endoscopy, a mobile part of an endorobot is introduced into the organ or vessel and controlled by a stationary part of the endorobot arranged outside the patient. During an examination of the gastrointestinal tract, the mobile part is swallowed by the patient. The mobile part moves through the body, propelled by peristalsis. Inside the patient, the mobile part of the endorobot executes certain functions, for example, records a number of images for diagnosing the organ or vessel, takes samples, or clamps wounds. In order to control an intended movement of the mobile part, a magnetic field is applied externally. The magnetic field also supplies a function element of the mobile part with current for executing the desired function. 
         [0004]    Generally, mechanical parts, such as a motor or a gear unit, demand high input and as a result are prone to faults. Such actuators are large or have only limited actuating forces. A power supply via a cable is difficult to use with an actuator of an endorobot. 
       SUMMARY 
       [0005]    The present embodiments may obviate one or more of the limitations or drawbacks inherent in the related art. For example, in one embodiment, an endoscopy device includes a small, simple or non-fault-prone mobile part of an endorobot. 
         [0006]    In one embodiment, an energy absorption element has a heat element and a function unit is able to fulfill a function through heat energy. A useful movement can be driven by heat, and a simple, very small and robust design of the actuator may be achieved. 
         [0007]    An endorobot is a robot that can operate at generally inaccessible points inside a body, such as a human body, without tissue-destroying intervention. The electromagnetic field is an alternating field. The energy absorption element may be identical with the heat element. The heat element has a substance that absorbs energy from the electromagnetic field, such as an alternating field. The substance may be for example, ferrite material, resistance wire, or iron powder. Other suitable substances may be used, such as active powder or granulated material, a coil or another solid or a liquid. Remagnetization losses in iron or ferritic material or else ohmic losses may be utilized. 
         [0008]    In one embodiment, the heat element may absorb energy direct from the electromagnetic field. The energy may be made directly available as working energy. The heat element converts energy from the electromagnetic field directly into heat. Consequently, conversion of the energy from the electromagnetic field into, for example, electrical energy, is not required. 
         [0009]    In one embodiment, a movement is generated. The heat element applies the force or energy needed for the movement. A large mechanical force may be generated in a simple manner and with a high degree of efficiency. 
         [0010]    In one embodiment, the actuator may be maintained in a robust condition. The function unit, in conjunction with a deformation produced by heating of the heat element, may execute a working movement. The function unit may be deformed. The function unit may include, for example, a piece of memory metal, which in a cold state stays in a first shape condition and when heated sufficiently passes into a second shape condition. The function unit may include, for example, a bimetal, which is deformed upon input of heat. 
         [0011]    In one embodiment, the heat element may be deformed upon heating and cooling. The deformation movement may be transferred to the function unit, which executes the working movement. The heat element may be deformed through heating, as a result of which a simple design of the actuator is possible. The heat element may include a deformable medium held in a wall. The wall may be deformed when the heat element is deformed. The wall may enclose a volume. The deformable medium may remain enclosed by the wall when the volume is changed in shape and/or size by the heating. The wall may be expandable. 
         [0012]    In one embodiment, the heat element may include a fluid that heats up, by virtue of which a change in the heating of the heat element may be achieved. The fluid is a liquid, a gas or a gel-like substance. If the fluid is a gas, then through heat input, a continuous change in volume of the fluid can be achieved. A steady movement of the function unit can be achieved. If the fluid is fashioned as a liquid or gel, the fluid may, through heat input, be evaporated so that a large volume change and thus a large functional movement may be achieved. 
         [0013]    The fluid deforms the heat element by a phase transition. The fluid has a boiling point, which lies only a few degrees above human body temperature, for example, between about 43° C. and 55° C. The fluid has a low heat capacity in the phase transition so that the heat input may be kept low. In a phase transition into the liquid or gel-like phase, the fluid emits only limited heat. In one embodiment, the fluid may include a mixture of gas and liquid, the quantity of liquid may determine a final size reached after full evaporation and the gas may determine initial size of the heat element existing prior to evaporation. 
         [0014]    In one embodiment, a function unit has an inner cavity with an outlet. The heat element presses, by a change in size, a substance out of the outlet. For example, when the actuator reaches a location in the body intended for a substance dose, the heat element may be heated and the substance pressed out of the inner cavity. 
         [0015]    In one embodiment, the heat element is prepared for the absorption of electromagnetic radiation from a predefined first absorption frequency band. The heat element may not substantially absorb or may only absorb in a limited way electromagnetic radiation from an adjacent second frequency band. Interference with control through the unwanted irradiation of electromagnetic radiation may be counteracted. The absorption frequency band is narrow. 
         [0016]    In one embodiment, the actuator has a plurality of heat elements that can be controlled separately. A function may be executed using a plurality of subfunctions. A large variety of functions may be executed using the subfunctions. For example, a complicated movement sequence may be composed of a series of individual movements. 
         [0017]    In one embodiment, the actuator may have a plurality of heat elements that absorb electromagnetic radiation from different absorption frequency bands. Depending on the frequency of an inducing electromagnetic field, a defined heat element may be controlled or a plurality of heat elements may be controlled simultaneously. Each heat element corresponds to one of the absorption frequency bands, which the heat element absorbs and leaves the other frequency bands unabsorbed. 
         [0018]    In one embodiment, an endorobot includes an actuator and a control unit that controls the actuator. The actuator may be mechanically separated from the control unit. The actuator may be used inside a human body. The control unit may remain outside the human body. The endorobot may also include a transmitter that radiates an electromagnetic field. The control unit may be mechanically rigidly connected (fixed) to the transmitter. The control unit may be coupled mechanically (directly or indirectly) to the actuator. For example, the actuator may include the control unit. The control unit may transmit (communicate) transmit commands from inside the body to the transmitter arranged outside the body. 
         [0019]    In one embodiment, the control unit controls a plurality of heat elements. The heat elements have a frequency assigned to the respective heat element. The frequencies differ from one another. A plurality of heat elements may be controlled independently and a variety of functions achieved. The frequencies may be frequency bands with a predetermined bandwidth. 
         [0020]    Control of the actuator may be achieved by a sensor that determines the size of the heat element. An operating status of the heat element may be determined, for example whether the heat element is currently large and executing an operating function or whether it is small and the operating function, for example, a movement, has been retracted. Depending on the current operating status of the heat element, a further operation may be initiated by the control unit. The size may be determined by ultrasound or by transillumination, for example, by X-ray radiation. A size of a volume of gas in a surrounding liquid may be determined by the sharp contrast between liquid and gas. A size change may be monitored by the control unit. A precise determination of a current operating status may be made based on the size change. 
         [0021]    Control of the actuator may also be based on a sensor that determines an energy absorption of the heat element. Depending on the energy absorption, it can be concluded how far the heat element has heated up and a current operating status can be determined from this. The energy absorption may be determined from a damping of the electromagnetic field. 
         [0022]    In one embodiment, a sensor may determine a shift of an absorption frequency band through a movement of the heat element or of the function means. The actuator may change absorption frequency bands when there is a change in the shape of the heat element or of the function means. A shape of the heat element may be determined by measuring the damping of the electromagnetic field at selected frequencies. 
         [0023]    In one embodiment, the inductance of the oscillating circuit of transmitter and actuator may be changed. An operating status may be determined based on the change of inductance. The energy absorption or the damping of the heat element may be measured purely qualitatively, for example, only as a relative change in an energy absorption, or quantitatively. 
         [0024]    In one embodiment, the endorobot comprises a plurality of sensors for the independent monitoring of a plurality of heat elements. A complicated operating sequence may be monitored reliably using the plurality of sensors. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  shows a patient having received one embodiment of an endorobot, 
           [0026]      FIG. 2  shows an actuator of the endorobot depicted in  FIG. 1 , 
           [0027]      FIG. 3  shows four further actuators of an endorobot, 
           [0028]      FIG. 4  shows one embodiment of an actuator in open and closed position, 
           [0029]      FIG. 5  shows one embodiment of an actuator in passive and active position, 
           [0030]      FIG. 6  shows one embodiment of a tripod with three actuators, 
           [0031]      FIG. 7  shows one embodiment of an actuator for expanding in passive and active position, 
           [0032]      FIG. 8  shows one embodiment of an actuator for holding in a vessel, in passive and active position, 
           [0033]      FIG. 9  shows one embodiment of an actuator that expels a fluid in passive and active position, 
           [0034]      FIG. 10  shows one embodiment of an actuator for controlled moving, 
           [0035]      FIG. 11  shows one embodiment of an actuator as depicted in  FIG. 10  in triple active status and 
           [0036]      FIG. 12  shows one embodiment of a movement sequence in a vessel of the actuator from  FIGS. 10 and 11 , with a control model. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]      FIG. 1  shows a patient  2  on a bed  4  with an endorobot  6 , which has an actuator  8 , shown only schematically in  FIG. 1 , a control unit  10  with a sensor  11  and a transmission wire  12 . The transmission wire  12  includes a transmit and receive coil, which generates an alternating electromagnetic field  14  and receives the alternating field  14 . The sensor  11  or control unit  10  measures the alternating field  14 . The control unit  10  may excite the alternating field  14  with one or more adjustable fixed or variable frequencies and may evaluate the receive signal received from the coil. 
         [0038]      FIG. 2  shows the actuator  8  of the endorobot as depicted in  FIG. 1 . The actuator  8  includes three energy absorption elements in the form of heat elements  16   a - c . The heat elements  16   a - c  may be connected to a function unit  18   a - c . The first heat element  16   a  may absorb electromagnetic radiation  14 , for example, radio radiation, through induction from a first absorption frequency band. The first absorption frequency band corresponds to material  20   a  of the heat element  16   a , for example, ferrite material, in such a way that the material  20   a  can readily absorb the electromagnetic radiation  14  and can readily convert it into heat through remagnetization losses. The heat elements  16   b  and  16   c  may be embodied similar to the heat element  16   a . The heat elements  16   b  and  16   c  may comprise a slightly different material  20   b ,  20   c , corresponding to a second or third absorption frequency band. The three absorption frequency bands are slightly different in their frequency position and do not overlap. Each heat element  16   a - c  leaves electromagnetic radiation from one of the adjacent frequency bands essentially unabsorbed. The three heat elements  16   a - c  may be controlled by the control unit  10  separately through three different excitation frequencies. The three function units  18   a - c  are fashioned fulfill their own function. 
         [0039]      FIG. 3  shows four different actuators  22   a - d  that include heat elements  24   a - d  and function unit  26   a - d . In the actuator  22   a , the heat element  24   a  and the function unit  26   a  are arranged in layers on top of one another. In the actuator  22   b , the heat element  24   b  includes many small elements in the function unit  26   b . Actuator  22   c  includes a heat element  24   c  that is arranged inside the function unit  26   c . Actuator  22   d  includes a heat element  24   d  that is arranged outside the function unit  26   d . The position of the heat elements  24   a - d  in relation to their function units  26   a - d  is determined by the function to be fulfilled by the function units  26   a - d.    
         [0040]    The actuators  8 ,  22   a - d  may cool the heat elements  16   a - c ,  24   a - d . The heat elements  16   a - c ,  24   a - d  may be arranged on the outside in the actuator  8 ,  22   a ,  22   d  and/or have a heat transfer unit that transfers heat from the heat element  16   a - c ,  24   b ,  24   c  to outside the actuator  8 ,  22   b ,  22   c . The heat transfer unit may include a function unit  26   b ,  26   c , which is provided for the transfer of heat. The thermal connection of the heat elements  16   a - c ,  24   a - d  to the surroundings of the actuator  8 ,  22   a - d  enables the heat elements  16   a - c ,  24   a - d  to cool rapidly after heating. The respective function units  18   a - c ,  26   a - d  may return rapidly to its initial status, for example, its starting position. 
         [0041]      FIGS. 4 to 12  show additional embodiments of actuators  28 ,  36 ,  60 ,  72 ,  84 ,  98 . The mode of operation is analogous to that of the above-described actuators  8 ,  22   a - d.    
         [0042]      FIG. 4  shows one embodiment of an actuator  28  that includes a heat element  30  and a function unit  32  with two gripping arms  34 , which are shown on the left-hand side of  FIG. 4  in the open position and on the right-hand side of  FIG. 4  in the closed position. One or both of the two gripping arms  34 , which rest in the open position when a heat element is cold, include memory metal. When the heat element  30  is heated, heat is transferred from the heat element  30  to the gripping arms  34 . At a predetermined temperature, the gripping arms  34  move into the closed position and remain there for as long as their temperature lies above the predetermined temperature. The gripping arms  34  may be used to grip (hold) a piece of tissue. The gripping arms  34  may be used to separate the gripped tissue from other tissue. 
         [0043]    In one embodiment, as shown in  FIG. 5 , the actuator  36  includes a heat element  38  and a function unit  44 . The heat element  38  may include an expandable container  42  filled with liquid  40 . The function unit  44  may include a die. The heat element  38  and function unit  44  may be disposed in a housing  46 . The housing  46  may include a wall  48  and a floor  50 . When the heat element  38  is heated, the liquid  40  is heated through the direct absorption of electromagnetic radiation or through radiation-absorbing particles, for example, ferrite particles. The liquid  40  may include the radiation-absorbing particles. The boiling point of the liquid  40  may be around 45° C. The heat capacity of the liquid  40  may be low. The liquid  40  may boil even when a low amount of heat is transferred to the liquid  40 . The container  42  may fill with gas  52  and expand. The die executes a working movement by being forced out of the housing  46 . When cooled, the die travels back into the housing  46  again. Alternatively, the floor  50  may include a heat element that transfers its heat to the liquid  40 . 
         [0044]    As shown in  FIG. 6 , a tripod  54  includes three actuators  36 . The tripod includes a base plate  56  and a working plate  58 . The heat elements  44  of the actuators  36  are set to different absorption frequency bands. The actuators  36  may be controlled independently of each other. The working plate  58  may be moved in three axes of freedom, for example, may be swiveled two-dimensionally and raised and lowered in the direction of displacement of the function units  44 . A tripod  54  may be used, for example, for moving a camera. 
         [0045]    In one embodiment, as shown in  FIG. 7 , an actuator  60  includes a heat element  62  and a function unit  64  having an outer skin. The heat element  62  includes an elastic material  66 , for example, a gel or an elastomer. The elastic material  66  absorbs energy from an alternating electromagnetic field either of its own accord or with the aid of embedded particles. The elastic material  66  may include liquid bubbles  68 , the liquid of which evaporates when heated sufficiently and gas bubbles  70  form as a result to cause an expansion of the outer skin. As shown in the right side of  FIG. 7 , a vessel may be expanded, for example, by using gas bubbles  70 . 
         [0046]    In one embodiment, as shown in a sectional view of  FIG. 8 , an actuator  72  includes a function unit  74  for holding in a vessel  76 . The heat element  78  of the actuator  72  includes a mixture of an absorption liquid  80  that absorbs energy from an alternating electromagnetic field and a liquid  72  that evaporates. The function unit  74  like the heat element  78  is elastic and may be directed (connected) around the heat element  78 . A plurality of separate holding elements may form the function unit  74 . 
         [0047]    As shown in  FIG. 9 , the actuator  84  may expel a medically active liquid  86  from an inner cavity  88  into the surroundings  90  of the actuator  84 . The actuator  84  may include a liquid  92  that serves as a heat element. When heated, the liquid  92  evaporates to form a gas  94 . The gas  94  displaces a die  96 , which forces the liquid  86  out of the inner cavity  88 . 
         [0048]    As shown in  FIGS. 10 and 11 , an actuator  98  is used for a targeted movement. The actuator  98  includes three separately controllable heat elements  100   a - c . The heat elements  100   a - c  lie in an evaporable medium that is distributed between three chambers  102   a - c . The chambers  102   a - c  are separated from one another in a gastight manner by two seals  104 . The chambers  102   a - c  may be expanded separately by the evaporable medium. The two outer chambers  102   a ,  102   c  are held constant in their expansion in an axial direction by two holders  106 , for example, a screw directed through the heat element  100   a ,  100   c . The central chamber  102   b  is limited in its expansion perpendicular to the axial direction by retaining rings  110 .  FIG. 10  shows the actuator  98  in tension-relieved status, for example, with cool heat elements  100   a - c .  FIG. 11  shows the actuator  98  with evaporated medium and maximally expanded chambers  102   a - c.    
         [0049]      FIG. 12  shows seven acts of movement of the actuator  98  through a vessel  112 . Shown in tabular form on the right-hand side of  FIG. 12  are the frequencies f 1 , f 2  and f 3  with which the transmission medium  12  radiates the alternating electromagnetic field. The heat element  100   a  absorbs radiation with the frequency f 1 , the heat element  100   b  absorbs radiation with the frequency f 2 , and the heat element  100   c  absorbs radiation with the frequency f 3 . The heat elements  100   a - c  leave radiation with the other two frequencies f 1 , f 2  or f 3  essentially unabsorbed. 
         [0050]    In a first act, no alternating electromagnetic field radiates from the transmission medium. Consequently, all three heat elements  100   a - c  are cool. The medium is relieved of tension everywhere and the chambers  102   a - c  are not expanded. In the second to the fourth acts, the transmission medium  12  radiates an alternating electromagnetic field with the frequency f 1 , then with f 2  and f 3 , and with all three frequencies f 1 , f 2  and f 3 . Initially only the first heat element  102   a , then two heat elements  102   a ,  102   b , and then all three heat elements  102   a - c  are heated. The actuator  98  in the vessel  112  is tensioned, expanded and then doubly tensioned. 
         [0051]    In the fifth act, through switching off of the first frequency f 1 , the heat element  100   a  emits its heat rapidly to the surroundings and cools down rapidly. The chamber  102   a  is relieved of tension. In the sixth act, the chamber  102   a  may be pulled by relieving tension of the second chamber  102   b  to the third chamber  102   c . In the seventh act, the chamber  102   a  is again expanded to double the tension in the vessel  112 . The movement process recommences with a fresh cycle from the second to the seventh acts. The cycle may be repeated for targeted movement through the vessel  112 . The movement may be controlled by the control unit  10 . Movement through a curved vessel is also possible without problems. The control unit controls the heat elements  100   a - c  using the frequency f 1 , f 2 , f 3  respectively assigned to the respective heat element  100   a - c.    
         [0052]    In one embodiment, the control unit  10  monitors behavior of the heat elements  16   a - c ,  24   a - d ,  30 ,  38 ,  62 ,  78 ,  100   a - c  with the aid of the sensor  11  and/or the coil. The sensor  11  serves to determine the size of the heat element  16   a - c ,  24   a - d ,  30 ,  38 ,  62 ,  78 ,  100   a - c  or volume of gas by ultrasound or X-ray radiation and/or to determine an energy absorption of the heat element  16   a - c ,  24   a - d ,  30 ,  38 ,  62 ,  78 ,  100   a - c  via damping of the alternating field. The control unit  10  may vary a frequency of the alternating field and to determine an absorption depending on the frequency. This produces an absorption displacement from which the control unit  10  determines with the aid of previously determined empirical data a movement or size status of the heat elements  16   a - c ,  24   a - d ,  30 ,  38 ,  62 ,  78 ,  100   a - c . The sensor  11  may include a plurality of sensor elements. The plurality of sensor elements may monitor independently a plurality of heat elements  16   a - c ,  24   a - d ,  30 ,  38 ,  62 ,  78 ,  100   a - c.    
         [0053]    Various embodiments described herein can be used alone or in combination with one another. The forgoing detailed description has described only a few of the many possible implementations of the present invention. For this reason, this detailed description is intended by way of illustration, and not by way of limitation. It is only the following claims, including all equivalents that are intended to define the scope of this invention.