Sensor and method enabling the determination of the position and orientation of a flexible element

{
  "publication_number": "US10260913B2",
  "country": "US",
  "kind": "B2",
  "title": "Sensor and method enabling the determination of the position and orientation of a flexible element",
  "abstract": "Disclosed is a sensor enabling positioning of a flexible element subject to applied forces. The sensor includes at least two spatially separated light permeable tubes, each having first and second ends arranged on respective first and second frame portions of the flexible element. At least one of the first or second ends of at least one light permeable tube are attached to a corresponding first frame portion by a joining unit. Each of the at least two spatially separated light permeable tubes includes at least one light detecting device, connectable to a processing unit, and arranged at a light detecting position of a corresponding light permeable tube to detect light from at least one light emitting device through the corresponding light permeable tube and transferring information including information relating to the detected light to the processing unit, enabling the processing unit to determine the bend of the light permeable tubes.",
  "claims": [
    "1. A sensor for enabling positioning of a flexible element subject to applied forces, the sensor comprises: at least two spatially separated light permeable tubes (1, 10) each tube having a first end (1 a, 10 a) arranged on a first frame portion (11 a) and a second end (1 b, 10 b) arranged on a second frame portion (11 b) of the flexible element, wherein at least one of said first end (1 a, 10 a) or said second end (1 b, 10 b) of at least one light permeable tube (1, 10) are attached to a corresponding first frame portion (11 a, 11 b) by means of a joining means (120); and wherein each of said at least two spatially separated light permeable tubes further comprises, at least one light detecting device (3), connectable to a processing unit (4), and arranged at a light detecting position of a corresponding light permeable tube (1, 10) and configured to detect light emitted from at least one light emitting device (2) through the corresponding light permeable tube (1, 10) and configured to transfer information comprising information relating to the detected light to the processing unit (4) to enable the processing unit to determine the bend of the light permeable tubes (1, 10).",
    "2. The sensor according to claim 1, wherein each end of at least one tube (1, 10) are attached to the corresponding frame portion (11 a, 11 b) by means of joining means (120).",
    "3. The sensor according to claim 1, wherein said joining means (120) comprises a spherical bearing or a universal joint.",
    "4. The sensor according to claim 3, wherein one end of at least one tube (1, 10) are attached by means of a spherical bearing and the other end of the at least one tube (1, 10) are attached by means of a universal joint.",
    "5. The sensor according to claim 1, wherein said sensor further comprises a light emitting device (3) comprising a plurality of light emitting diodes, each light emitting diode being configured to emit light of a pre-determined wavelength.",
    "6. The sensor according to claim 1, wherein said sensor further comprises at least one reference detector (30, 350, 355), said at least one reference detector being arranged in the vicinity of the light emitting device (2) and being configured to detect light emitted from the light emitting device before said light enters said light permeable tubes (1, 10) to obtain reference values for certain light characteristics of said emitted light.",
    "7. The sensor according to claim 6, wherein the sensor also comprises a beam-splitter arranged between the light emitting device (3) and the light permeable tube, said beam-splitter being configured to direct part of the light emitted from the light emitting device (3) to the reference detector (30).",
    "8. The sensor according to claim 1, wherein said sensor further comprises at least one diffusion filter (45, 450) arranged between the light emitting device (3) and the light permeable tube (1).",
    "9. The sensor according to claim 1, wherein said sensor comprises six spatially separated light permeable tubes (1, 10).",
    "10. The sensor according to claim 1, wherein the number of light detecting devices (3) and light emitting devices corresponds to the number of light permeable tubes and wherein each of said light detecting device (3) and said light emitting device (2) are used for a designated light permeable tube (1, 10).",
    "11. The sensor according to claim 1, wherein said light emitting device (2) comprises a laser and wherein said light detecting device (3) comprises an array of light detecting devices (3).",
    "12. A flexible element comprising a sensor according to claim 1.",
    "13. The flexible element according to claim 12, wherein said flexible element further comprises a protective casing (65) enclosing parts of the flexible element.",
    "14. The flexible element according to claim 13, wherein said protective casing comprises at least one segment (66) of an elastic material.",
    "15. A method for determining the orientation of a moving frame portion of a flexible element by using a sensor according to claim 1, the method comprises the steps of: obtaining (S 1) values of detected light intensities for light having propagated through different light permeable tubes; and converting (S 2) the obtained values of the detected light intensities to corresponding length values representing particular distances between said moving frame portion and a second frame portion of said flexible element fixed relative said moving frame portion; determining (S 3) the position and/or the orientation of the moving frame portion relative the fixed frame portion by utilizing the length values as input in a numerical direct kinematic method.",
    "16. The sensor according to claim 2, wherein said joining means (120) comprises a spherical bearing or a universal joint.",
    "17. The sensor according to claim 2, wherein said sensor further comprises a light emitting device (3) comprising a plurality of light emitting diodes, each light emitting diode being configured to emit light of a pre-determined wavelength.",
    "18. The sensor according to claim 3, wherein said sensor further comprises a light emitting device (3) comprising a plurality of light emitting diodes, each light emitting diode being configured to emit light of a pre-determined wavelength.",
    "19. The sensor according to claim 4, wherein said sensor further comprises a light emitting device (3) comprising a plurality of light emitting diodes, each light emitting diode being configured to emit light of a pre-determined wavelength.",
    "20. The sensor according to claim 2, wherein said sensor further comprises at least one reference detector (30, 350, 355), said at least one reference detector being arranged in the vicinity of the light emitting device (2) and being configured to detect light emitted from the light emitting device before said light enters said light permeable tubes (1, 10) to obtain reference values for certain light characteristics of said emitted light."
  ],
  "description_excerpt": "The proposed technology generally relates to a sensor and a method that enables the determination of the position and orientation of a flexible element subject to applied forces and torques.\n\nOne of the problems in traditional robotics is that the limbs of a robot must be bend resistant so that the position of the end effector can be positioned by summing the vectors from each axis rotation point. To make the limbs bend resistant the most common approach is to manufacture them out of metal. This results in excessively heavy robots that demand a high amount of power during operation. In mobile robotics this renders a relatively low battery time which in turn limits the capabilities of the robot. The weight of the robot limbs can be reduced by introducing more light weighted materials such as carbon fiber, which has a high strength to weight ratio. This on the other hand has the downside that the limbs will be prone to bending. This proposal therefore results in decreased energy demands but also a decrease in precision. Many different methods have been proposed to model robots with bending limbs, also referred to as continuum robots, all resulting in more or less precise 3D positioning results depending on what sensor data is used. Sensors used in continuum robotic limbs make use of force sensors attached to varying parts of the robot (Ref. 1). X-Rays and other visual systems have also been used in shape estimation see e.g. (Ref. 2) and (Ref. 3). Positioning using optical fibers have been proposed where three pairs of optical fibers are attached on the robot. Light is emitted through one of the fibers in each pair.",
  "cpc": [
    "G01D 5/353",
    "B25J 18/06",
    "B25J 19/021",
    "B25J 19/022",
    "B25J 19/025",
    "G01B 11/16",
    "G01B 11/24",
    "G01B 11/255",
    "G01D 5/26",
    "G01D 5/268",
    "G01D 5/34",
    "G01D 5/35345"
  ],
  "ipc": [
    "G01B 11/16",
    "G01B 11/255",
    "G01D 5/34",
    "G01D 5/353"
  ],
  "assignees": [
    "FEATHERWAY ROBOTICS AB"
  ],
  "inventors": [
    "SALOMONSSON NIKLAS"
  ],
  "filing_date": "2016-01-22",
  "publication_date": "2019-04-16",
  "grant_date": "2019-04-16",
  "priority_date": "2015-01-22",
  "application_number": "US-201615545564-A",
  "family_id": "56417468",
  "citations": [
    "DE102006048635A1",
    "DE4002293A1",
    "EP1635034A1",
    "GB2286242A",
    "US2002128783A1",
    "US2006045408A1",
    "US2007116415A1",
    "US2007156019A1",
    "US2011292049A1",
    "US2012035437A1",
    "US2015141768A1",
    "US4542291A",
    "US4727247A",
    "US5026141A",
    "US5633494A",
    "US5818982A",
    "US6389187B1",
    "US6471710B1",
    "US7356238B2",
    "WO0113060A1",
    "WO2015016765A1",
    "WO9429671A1",
    "WO9913306A2"
  ]
}