# US 12,004,833 B2 · System and method for maintaining a tool position and orientation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,004,833 B2 - Document ID: US12004833B2 - Status: Granted - Kind: B2 - Application number: 18/330,438 - Filed: 2023-06-07 - Published: 2023-10-05 - Granted: 2024-06-11 - Earliest claimed: 2014-03-17 - Assignees: Intuitive Surgical Operations, Inc. - Applicants: Intuitive Surgical Operations, Inc. - Inventors: Brandon D. Itkowitz; Nitish Swarup; Paul G. Griffiths; Goran Lynch - Web page: https://patentgrep.com/patent/US12004833B2 ## CPC - A61B 34/70: {Manipulators specially adapted for use in surgery} - A61B 1/00149: {using articulated arms} - A61B 34/30: Surgical robots - B25J 9/1607: {Calculation of inertia, jacobian matrixes and inverses} - B25J 9/1633: {compliant, force, torque control, e.g. combined with position control} - A61B 2017/00017: {Electrical control of surgical instruments} - A61B 2034/2059: {Mechanical position encoders} - A61B 2034/301: {for introducing or steering flexible instruments inserted into the body, e.g. catheters or endoscopes} - A61B 2034/304: {including a freely orientable platform, e.g. so called 'Stewart platforms'} - A61B 2034/305: {Details of wrist mechanisms at distal ends of robotic arms} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50}) ## Abstract Techniques for maintaining instrument position and orientation include a computer-assisted device having a control unit and an articulated structure. The articulated structure includes a plurality of joints and is configured to support an instrument. The control unit is configured to determine an error that is introduced, by movement of a first joint of the plurality of joints, to a position of the instrument, an orientation of the instrument, or both the position of the instrument and the orientation of the instrument; and in response at least to determining that a second joint of the plurality of joints is at a range of motion limit or is about to reach the range of motion limit drive one or more joints of the plurality of joints to partially reduce the error, the one or more joints not comprising the second joint, and provide feedback that not all of the error is reduced. ## Claims ### Claim 1 A computer-assisted device comprising: an articulated structure comprising a plurality of joints, the articulated structure being configured to support an instrument; and a control unit coupled to the articulated structure; wherein the control unit is configured to: determine an error that is introduced, by movement of a first joint of the plurality of joints, to a position of the instrument, an orientation of the instrument, or both the position of the instrument and the orientation of the instrument; and in response at least to determining that a second joint of the plurality of joints is at a range of motion limit or is about to reach the range of motion limit: drive one or more joints of the plurality of joints to partially reduce the error, the one or more joints not comprising the second joint, and provide feedback that not all of the error is reduced. ### Claim 2 (depends on 1) The computer-assisted device of claim 1, wherein the feedback includes at least one feedback type selected from the group consisting of: partially applying a brake to the second joint; and applying a motion resistance signal to an actuator associated with the second joint. ### Claim 3 (depends on 1) The computer-assisted device of claim 1, wherein the control unit is further configured to: unlock a third joint of the plurality of joints, wherein unlocking the third joint reduces an amount the second joint is driven in order to partially compensate for the error. ### Claim 4 (depends on 1) The computer-assisted device of claim 1, wherein the control unit is further configured to: lock a third joint of the plurality of joints to prevent relative movement of the third joint while the one or more joints are being driven. ### Claim 5 (depends on 1) The computer-assisted device of claim 1, wherein to determine the error, the control unit is configured to: determine an initial position and an initial orientation of the instrument prior to movement of the first joint; determine a current position and a current orientation of the instrument while the first joint is being moved; and determine the error based on a difference between the current position and the initial position, a difference between the current orientation and the initial orientation, or both the difference between the current position and the initial position and the difference between the current orientation and the initial orientation. ### Claim 6 (depends on 1) The computer-assisted device of claim 1, wherein to determine the error, the control unit is configured to: determine a reference coordinate frame for the instrument; determine a reference transform of the instrument in the reference coordinate frame prior to the movement of the first joint; determine an actual transform of the instrument in the reference coordinate frame while the first joint is being moved; and determine the error based on differences between the actual transform of the instrument and the reference transform of the instrument. ### Claim 7 (depends on 6) The computer-assisted device of claim 6, wherein the control unit determines the reference coordinate frame for the instrument based on a cause of the movement of the first joint. ### Claim 8 (depends on 7) The computer-assisted device of claim 7, wherein, when the movement of the first joint is due to movement of a patient coupled to the articulated structure, the reference coordinate frame associated with a remote center of the articulated structure. ### Claim 9 (depends on 8) The computer-assisted device of claim 8, wherein, when the movement of the first joint is due to controlled motion of the articulated structure, due to manual repositioning of the articulated structure, due to motion induced by a collision, or due to release of a brake or lock of the first joint, the reference coordinate frame is fixed relative to a world coordinate frame associated with the computer-assisted device. ### Claim 10 (depends on 8) The computer-assisted device of claim 8, wherein the control unit determines the reference transform and the actual transform based on positions of joints of the plurality of joints and one or more kinematic models of the computer-assisted device. ### Claim 11 (depends on 6) The computer-assisted device of claim 6, wherein to determine the differences between the actual transform and the reference transform, the control unit is configured to compose an inverse of the reference transform with the actual transform. ### Claim 12 A method of controlling a computer-assisted device comprising an articulated structure, the method comprising: determining, by a control unit, an error that is introduced, by movement of a first joint of a plurality of joints of the articulated structure, to a position of an instrument, an orientation of the instrument, or both the position of the instrument and the orientation of the instrument, the instrument being supported by the articulated structure; and in response at least to determining that a second joint of the plurality of joints is at a range of motion limit or is about to reach the range of motion limit: driving one or more joints of the plurality of joints to partially reduce the error, the one or more joints not comprising the second joint, and provide feedback that not all of the error is reduced. ### Claim 13 (depends on 12) The method of claim 12, wherein the feedback includes at least one feedback type selected from the group consisting of: partially applying a brake to the second joint; and applying a motion resistance signal to an actuator associated with the second joint. ### Claim 14 (depends on 12) The method of claim 12, further comprising: unlocking, by the control unit, a third joint of the plurality of joints, wherein unlocking the third joint reduces an amount the second joint is driven in order to maintain the position and the orientation of the instrument. ### Claim 15 (depends on 12) The method of claim 12, further comprising: locking, by the control unit, a third joint of the plurality of joints to prevent relative movement of the third joint while the one or more joints are being driven. ### Claim 16 (depends on 12) The method of claim 12, wherein to determine the error, the control unit is configured to: determine an initial position and an initial orientation of the instrument prior to movement of the first joint; determine a current position and a current orientation of the instrument while the first joint is being moved; and determine the error based on a difference between the current position and the initial position, a difference between the current orientation and the initial orientation, or both the difference between the current position and the initial position and the difference between the current orientation and the initial orientation. ### Claim 17 A non-transitory machine-readable medium including a plurality of machine-readable instructions which, when executed by one or more processors associated with a computer-assisted device, are adapted to cause the one or more processors to perform a method comprising: determining an error introduced, by movement of a first joint of a plurality of joints of an articulated structure com the computer-assisted device, into a position and an orientation of an instrument supported by the articulated structure and in response to determining that a second joint of the plurality of joints is at a range of motion limit or is about to reach the range of motion limit: driving one or more joints of the plurality of joints to partially compensate for the error, the one or more joints not comprising the second joint, and providing feedback that not all of the error is reduced. ### Claim 18 (depends on 17) The non-transitory machine-readable medium of claim 17, wherein the feedback includes at least one feedback type selected from the group consisting of: partially applying a brake to the second joint; and applying a motion resistance signal to an actuator associated with the second joint. ### Claim 19 (depends on 17) The non-transitory machine-readable medium of claim 17, wherein the method further comprises: unlocking a third joint of the plurality of joints, wherein unlocking the third joint reduces an amount the second joint is driven in order to maintain the position and the orientation of the instrument. ### Claim 20 (depends on 17) The non-transitory machine-readable medium of claim 17, wherein the method further comprises: locking a third joint of the plurality of joints to prevent relative movement of the third joint while the one or more joints are being driven.