Patent Description:
The end effector is inserted into a small incision (via a cannula) or a natural orifice of a patient to position the end effector at a work site within the body of the patient. Some robotic surgical systems include a robotic console supporting a robot arm, and at least one end effector such as a scalpel, a forceps, or a grasping tool that is mounted to the robot arm.

In general, the user interface includes an input controller or handle that is moveable by the surgeon to control the robotic surgical system. Robotic surgical systems typically use a scaling factor to scale down the motions of the surgeons hands to determine the desired position of the robotic instruments within the patient. Often this scaling factor requires the motions of the handles to be larger than the range of motion of the input handle. The handles therefore reach a boundary limit of the workspace and prevent the surgeon from completing the desired motion. Current robotic surgical systems on the market use a feature called "clutching" to decouple the motion of the input handles from the robotic instruments. The surgeon is then free to move the handles to a new position within the workspace of the user interface while the instruments remain stationary. Once the input handle is away from the workspace boundary, the surgeon can "reclutch" to recouple the motion of the input handle to complete the desired motion with the robotic instrument.

During a robotic surgical procedure, the robot arm or end effector may collide with tissue, an organ, or another surgical implement (e.g., another robot arm or end effector, access port, or camera). Such collisions can create a positional mismatch between the position of the input handles and the robot arm or end effector associated with the input handle. This positional mismatch can create undesired motions of the robot arm or the end effector during the surgical procedure. <CIT> describes a medical robotic system that includes a robotically controlled surgical instrument which includes a constraint controller that constrains the movement of the instrument based on a predetermined parameter. <CIT> describes systems and methods for performing robotically-assisted surgical procedures on a patient enable an image display device to provide an operator with auxiliary information related to the surgical procedure.

Accordingly, there is a need for collision handling algorithms for robotic surgical system.

Dependent claims disclose exemplary embodiments. Any methods of surgery in the disclosure are not claimed, but provide a better understanding of the invention.

In an aspect of the present disclosure, a method of collision handling for a robotic surgical system includes slipping an input handle of a user interface of the robotic surgical system relative to a pose of a tool of a surgical robot of the robotic surgical system when a portion of the surgical robot collides with an obstruction and an input handle is moved in a direction that corresponds to moving the tool towards the obstruction. The input handle having an offset relative to a desired pose of the tool after the input handle is slipped.

In aspects, the method includes moving the input handle in a direction to move the portion of the surgical robot away from the obstruction after the slipping of the input handle. The input handle may move a distance corresponding to the offset before the tool moves in a direction away from the obstruction. Alternatively, the tool may move in a direction away from the obstruction while maintaining a trim between a position of the input handle and a pose of the tool. The trim may be equal to the offset or the method may include dynamically scaling movement of the input handle relative to the pose of the tool in a direction parallel to the offset until the trim reaches a predetermined value. The predetermined value may be zero or nonzero.

In some aspects, slipping the handle relative to the pose of the tool occurs after the surgical robot reaches the predetermined force threshold to move the tool towards a desired pose. The method may further include a processing unit of the robotic surgical system to define the offset between a threshold position of the input handle when the tool reaches the predetermined force threshold and a position of the input handle after the input handle is pushed beyond the threshold position. The method may include the robotic surgical system providing force feedback to a clinician to resist slipping of the input handle beyond the threshold position.

In another aspect of the present disclosure, a method of collision handling of a robotic surgical system with a processing unit of the robotic surgical system includes receiving a first input signal from a user interface of the robotic surgical system to move a tool of a surgical robot of the robotic surgical system to a desired pose of the tool, transmitting an input control signal to the surgical robot to move the tool towards the desired pose, receiving a feedback signal from the surgical robot that a force to move the tool towards the desired pose is greater than a predetermined threshold, maintaining the tool at a threshold pose when the predetermined threshold is reached, and slipping a position of the input handle relative to the threshold pose to a second position of the input handle to define an offset between the second position of the input handle and a desired pose of the tool corresponding to the second position of the input handle.

In aspects, the method includes transmitting a feedback control signal to the user interface to resist movement of the input handle beyond a threshold position corresponding to the threshold pose of the tool.

In some aspects, the method includes receiving a second input signal from the user interface after slipping the position of the input handle indicative of the input handle moving towards a threshold position corresponding to the threshold pose of the tool. The method may include maintaining the tool in the threshold pose in responds to receiving the second input signal. Alternatively, the method may include transmitting a second control signal to the surgical robot to move the tool away from the desired pose with a trim defined between the input handle and the pose of the tool. Transmitting the second control signal may include the trim being equal to the offset between the second position of the input handle and the desired pose of the tool corresponding to the second position of the input handle. The method may include dynamically scaling movement of the input handle to the pose of the tool to reduce the trim between the position of the input handle and the pose of the tool until the trim reaches a predetermined value. The predetermined value may be zero or nonzero.

Various aspects of the present disclosure are described hereinbelow with reference to the drawings, which are incorporated in and constitute a part of this specification, wherein:.

Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As used herein, the term "clinician" refers to a doctor, a nurse, or any other care provider and may include support personnel. Throughout this description, the term "proximal" refers to the portion of the device or component thereof that is closest to the clinician and the term "distal" refers to the portion of the device or component thereof that is farthest from the clinician. In addition, as used herein the term "neutral" is understood to mean non-scaled.

This disclosure generally relates to collision handling and collision recovery algorithms or methods for robotic surgical systems. Specifically, for collision handling a processing unit of a robotic surgical system may allow an input handle of a user interface to slip beyond a position corresponding to a pose of a tool of a surgical robot when a portion of the surgical robot collides with an obstruction. Slipping the input handle relative to the pose of the tool defines an offset between the position of the input handle and a pose of the tool.

To recover from the collision, the input handle may move through the entire offset before the tool moves from the pose when the surgical robot collided with the obstruction. Alternatively, any movement of the input handle to move the surgical robot away from the obstruction would move the surgical robot away from the obstruction such that a trim is defined between the position of the input handle and a pose of the tool. The trim may be equal to the offset or the robot surgical system may dynamically scale movement of the surgical robot to reduce or remove the trim in a manner imperceptible to a clinician.

Referring to <FIG>, a robotic surgical system <NUM> in accordance with the present disclosure is shown generally as a surgical robot <NUM>, a processing unit <NUM>, and a user interface <NUM>. The surgical robot <NUM> generally includes linkages <NUM> and a robot base <NUM>. The linkages <NUM> moveably support an end effector or tool <NUM> which is configured to act on tissue. The linkages <NUM> may be in the form of arms each having an end <NUM> that supports an end effector or tool <NUM> which is configured to act on tissue. In addition, the ends <NUM> of the linkages <NUM> may include an imaging device <NUM> for imaging a surgical site "S". The user interface <NUM> is in communication with robot base <NUM> through the processing unit <NUM>.

The user interface <NUM> includes a display device <NUM> which is configured to display three-dimensional images. The display device <NUM> displays three-dimensional images of the surgical site "S" which may include data captured by imaging devices <NUM> positioned on the ends <NUM> of the linkages <NUM> and/or include data captured by imaging devices that are positioned about the surgical theater (e.g., an imaging device positioned within the surgical site "S", an imaging device positioned adjacent the patient "P", imaging device <NUM> positioned at a distal end of an imaging arm <NUM>). The imaging devices (e.g., imaging devices <NUM>, <NUM>) may capture visual images, infra-red images, ultrasound images, X-ray images, thermal images, and/or any other known real-time images of the surgical site "S". The imaging devices transmit captured imaging data to the processing unit <NUM> which creates three-dimensional images of the surgical site "S" in real-time from the imaging data and transmits the three-dimensional images to the display device <NUM> for display.

The user interface <NUM> also includes input handles <NUM> which are supported on control arms <NUM> which allow a clinician to manipulate the surgical robot <NUM> (e.g., move the arms <NUM>, the ends <NUM> of the linkages <NUM>, and/or the tools <NUM>). Each of the input handles <NUM> is in communication with the processing unit <NUM> to transmit control signals thereto and to receive feedback signals therefrom. Additionally or alternatively, each of the input handles <NUM> may include input devices <NUM> (<FIG>) which allow the surgeon to manipulate (e.g., clamp, grasp, fire, open, close, rotate, thrust, slice, etc.) the tools <NUM> supported at the ends <NUM> of the linkages <NUM>.

With additional reference to <FIG>, each of the input handles <NUM> is moveable through a predefined workspace to move the ends <NUM> of the linkages <NUM>, e.g., tools <NUM> (<FIG>), within a surgical site "S". The three-dimensional images on the display device <NUM> are orientated such that the movement of the input handles <NUM> moves the ends <NUM> of the linkages <NUM> as viewed on the display device <NUM>. The three-dimensional images remain stationary while movement of the input handles <NUM> is scaled to movement of the ends <NUM> of the linkages <NUM> within the three-dimensional images. To maintain an orientation of the three-dimensional images, kinematic mapping of the input handles <NUM> is based on a camera orientation relative to an orientation of the ends <NUM> of the linkages <NUM>. The orientation of the three-dimensional images on the display device <NUM> may be mirrored or rotated relative to view from above the patient "P". In addition, the size of the three-dimensional images on the display device <NUM> may be scaled to be larger or smaller than the actual structures of the surgical site permitting a clinician to have a better view of structures within the surgical site "S". As the input handles <NUM> are moved, the tools <NUM> are moved within the surgical site "S" as detailed below. Movement of the tools <NUM> may also include movement of the ends <NUM> of the linkages <NUM> which support the tools <NUM>.

For a detailed discussion of the construction and operation of a robotic surgical system <NUM>, reference may be made to <CIT>.

The movement of the tools <NUM> is scaled relative to the movement of the input handles <NUM>. When the input handles <NUM> are moved within a predefined workspace, the input handles <NUM> send input signals to the processing unit <NUM>. The processing unit <NUM> analyzes the input signals to move the tools <NUM> in response to the input signals. The processing unit <NUM> transmits scaled control signals to the robot base <NUM> to move the tools <NUM> in response to the movement of the input handles <NUM>. The processing unit <NUM> scales the input signals by dividing an Inputdistance (e.g., the distance moved by one of the input handles <NUM>) by a scaling factor SF to arrive at a scaled Outputdistance (e.g., the distance that one of the ends <NUM> is moved). The scaling factor SF is in a range between about <NUM> and about <NUM> (e.g., <NUM>). This scaling is represented by the following equation: <MAT> It will be appreciated that the larger the scaling factor SF the smaller the movement of the tools <NUM> relative to the movement of the input handles <NUM>.

For a detailed description of scaling movement of the input handle <NUM> along the X, Y, and Z coordinate axes to movement of the tool <NUM>, reference may be made to commonly owned <CIT>, and International Patent Application No.<CIT>.

Referring to <FIG>, during a robotic surgical procedure, a clinician interfaces with the input handle <NUM> to manipulate the tool <NUM> within the surgical site "S". As the tool <NUM> is moved within the surgical site "S", a clinician can visualize movement of the tool <NUM> within the surgical site "S" on the display <NUM>.

To manipulate the tool <NUM>, a clinician moves an input handle <NUM> from a first position "P1" to a second position "P2", shown in dashed lines (<FIG>). The processing unit <NUM> receives an input signal sent from the user interface <NUM> and transmits a control signal to the surgical robot <NUM> to move the tool <NUM> from a first pose to a second pose. For example, the input handle <NUM> is moved a distance along a control X axis in a direction illustrated by arrow "M1" and the tool <NUM> is moved in a direction along a robotic X axis illustrated by arrow "R1" representing movement of the tool <NUM> from a first pose "T1" towards a second pose "T2".

During movement of the tool <NUM> from the first pose "T1" towards the second pose "T2", the tool <NUM> may collide with an obstruction within the surgical site "S", e.g., tissue T, another tool <NUM>, an organ, or other surgical implement. When the tool <NUM> collides with the obstruction, the processing unit <NUM> receives a feedback signal from the surgical robot <NUM> and transmits a feedback control signal to the user interface <NUM>. In response to receiving the feedback control signal, the user interface provides force feedback to the clinician indicative of the tool <NUM> colliding with the obstruction. For example, the clinician may feel resistance to continued movement along the control X axis in the direction of the arrow "M1".

When the clinician feels the force feedback, the clinician may push the input handle <NUM> against the force feedback (e.g., in a direction opposite to the direction of the force feedback) and continue to move the input handle <NUM> along the control X axis in the direction of arrow "M1". In response, the processing unit <NUM> continues to send control signals to the surgical robot <NUM> to move the tool <NUM> along the robotic X axis in the direction of arrow "R1" until the force of the surgical robot <NUM>, to continue movement of the tool <NUM> along the robotic X axis, exceeds a predetermined threshold. The predetermined threshold may be determined by a deflection of a portion of the surgical robot <NUM> or by a torque at one or more joints of the surgical robot <NUM>. When the force of the surgical robot <NUM> exceeds the predetermined threshold, the surgical robot <NUM> "clutches" the movement of the input handle <NUM> from movement of the robotic system <NUM>, scales down movement of the input handle <NUM> from movement of the surgical robot <NUM>, and/or any other known means of collision handling. For a detailed discussion of systems and methods for detecting and handling of a collision of a tool or linkage of a robotic system and an obstruction reference may be made to <CIT>, and entitled "SURGICAL ROBOT INCLUDING TORQUE SENSORS.

With particular reference to <FIG>, the force to move the tool <NUM> along the robotic X axis was reached the predetermined threshold when the input handle <NUM> was positioned at a threshold position "PT". As shown, the input handle <NUM> was pushed through the threshold position "PT" to the second position "P2". As the input handle <NUM> is moved between the threshold position "PT" and the second position "P2" the tool <NUM> is substantially stationary within the surgical site "S", e.g., the tool <NUM> remains in the first pose "T1" as shown in <FIG>, such that the input handle <NUM> "slips" relative to the tool <NUM>. This "slipping" of the input handle <NUM> relative to the tool <NUM> results in a position mismatch between a desired pose "T2" of the tool <NUM> based on the position of the input handle <NUM> and the actual pose of the tool <NUM> which remains at the first pose "T1".

With the input handle <NUM> in the second position "P2", the surgical robot <NUM> maintains the tool <NUM> at the first pose "T1", the pose at which the predetermined threshold was reached, until the input handle <NUM> is moved along the control X axis in a direction that requires a force below the predetermined threshold to reposition the tool <NUM> along the robotic X axis, e.g., in a direction opposite the arrow "R1".

This position mismatch can create undesired motions of the tool <NUM> within the surgical site "S" during a surgical procedure. For example, when the input handle <NUM> is in the second position "P2", the tool <NUM> may be maintained in the first pose "T1" with the predetermined threshold force being directed towards an obstruction, e.g., tissue "T", such that, were the tool <NUM> to free itself from the obstruction, the tool <NUM> may move towards desired pose "T2" unexpectedly and/or at an undesired high velocity.

With reference to <FIG>, a method <NUM> for slipping the input handle <NUM> relative to the tool <NUM> in an event of a collision with an obstruction and a method for collision recovery is disclosed, in accordance with the present disclosure, with reference to the robotic surgical system <NUM> of <FIG>. As detailed below, a collision between a tool <NUM> and tissue "T" of a patient is described; however, such a collision may be between any portion of the surgical robot <NUM> and an obstruction. For example, a collision may occur between a linkage <NUM> of the surgical robot <NUM> and another linkage <NUM>.

Initially, a clinician moves the input handle <NUM> in a first direction along the control X axis towards the second position "P2" and transmits an input signal indicative of the movement (Step <NUM>). The processing unit <NUM> receives the input signal (Step <NUM>) and transmits an input control signal to move the tool <NUM> towards the desired pose of the surgical robot <NUM> (Step <NUM>). The surgical robot <NUM> receives the control signal and moves the tool <NUM>, and thus the surgical robot <NUM>, towards the desired pose "T2" (Step <NUM>).

As the tool <NUM> is moved towards the desired pose "T2", a portion of the surgical robot <NUM>, e.g., tool <NUM>, may collide with tissue "T" such that the surgical robot <NUM> would require a force greater than a predetermined threshold to continue to move the surgical robot <NUM> towards the desired pose "T2" (Step <NUM>); this pose is defined as the threshold pose "T1". When the predetermined threshold is reached or exceeded, the surgical robot <NUM> transmits a feedback signal to the processing unit <NUM>.

The processing unit <NUM> receives the feedback signal (Step <NUM>) from the surgical robot <NUM> and transmits a control signal to the surgical robot <NUM> (Step <NUM>) to maintain the surgical robot at the threshold pose "T1" (Step <NUM>). In addition, the processing unit <NUM> transmits a feedback control signal to the user interface <NUM> (Step <NUM>). In response to the feedback control signal, a clinician experiences force feedback against moving the input handle beyond a threshold position "PT" that corresponds to the threshold pose "T1" of the surgical robot <NUM> (Step <NUM>).

The clinician may push the input handle <NUM> in the first direction through the force feedback of the user interface <NUM> to a second position "P2" (Step <NUM>). The processing unit <NUM> receives an input signal in response to movement of the input handle <NUM> in the first direction and slips the position of the input handle <NUM> relative to the pose of the surgical robot <NUM> (Step <NUM>). As the input handle <NUM> is moved beyond the threshold position "PT" an offset is generated along the control X axis as the input handle <NUM> is "slipped" between the threshold position "PT" and the second position "P2". The offset represents movement of the input handle <NUM> beyond the point at which the position of the input handle <NUM> corresponds to the pose of the surgical robot <NUM>, e.g., the threshold position "PT", and the position of the input handle <NUM>, e.g., the second position "P2".

With the input handle <NUM> at the second position "P2", the input handle <NUM> can be moved along the control X axis in a second direction away from the obstruction, e.g., the direction opposite the arrow "M1", (Step <NUM>) such that the input handle <NUM> moves through a dead zone equal to the offset between the second position "P2" and the threshold position "PT" before the tool <NUM> of the surgical robot <NUM> moves along the robot X axis in a direction opposite the arrow "R1". Once the input handle <NUM> returns to the threshold position "PT" along the control X axis, the surgical robot <NUM> is recovered from the collision such that the surgical robot <NUM> moves the tool <NUM> along the robot X axis in response to additional movement of the input handle <NUM> in the second direction (Steps <NUM>, <NUM>, <NUM>, <NUM>). It will be appreciated that movement of the input handle <NUM> along the control X axis towards the threshold position "PT" will be allowed with little or no resistance, e.g., force feedback, while additional movement of the input handle <NUM> along the control X axis away from the threshold position "PT" will be resisted with additional force feedback.

With additional reference to <FIG>, another method <NUM> of collision recovery is disclosed in accordance with the present disclosure. After the processing unit <NUM> slips the position of the input handle <NUM> relative to the threshold pose of the surgical robot <NUM> to define an offset.

(Step <NUM>), the input handle <NUM> is moved in the second direction along the control X axis (Step <NUM>). The processing unit <NUM> receives an input signal indicative of the movement of the input handle <NUM> in the second direction (Step <NUM>) and transmits a second control signal to the surgical robot <NUM> to move away from the threshold pose "T2" with a trim between the input handle and the pose of the surgical robot (Step <NUM>). It will be appreciated that the trim is substantially equal to the offset between the threshold position "PT" and the second position "P2". The surgical robot <NUM> receives the second control signal and moves the surgical robot <NUM> away from the threshold pose (Step <NUM>). The robotic surgical system <NUM> may continue to manipulate the surgical robot <NUM> in response to movements of the input handle <NUM> with the trim maintained between the position of the input handle <NUM> and the pose of the surgical robot <NUM>.

According to the invention, the robotic surgical system <NUM> dynamically scales the movement of the input handle <NUM> and the tool <NUM> to reduce or eliminate the trim in a manner imperceptible to a clinician. For example, the input handle <NUM> can be moved in the first and second directions along the control X axis such that input signals are transmitted to the processing unit <NUM> (Step <NUM>). The processing unit <NUM> receives the input signals (Step <NUM>) and dynamically scales movements of the input handle <NUM> to reduce the trim between the input handle <NUM> and the pose of the surgical robot <NUM> (Step <NUM>). The processing unit <NUM> transmits scaled control signals to the surgical robot <NUM> (Step <NUM>) which moves the surgical robot <NUM> in response to the scaled control signals (Step <NUM>). The trim is reduced to a predetermined value and the robotic surgical system <NUM> may continue to move the surgical robot <NUM> in response to movement of the input handle <NUM>. In particular embodiments, the predetermined value of the trim is nonzero and in other embodiments the trim is reduced to zero such that the position of the input handle <NUM> corresponds to the pose of the surgical robot <NUM>.

For a detailed discussion of a robotic surgical system functioning with an offset and/or dynamic scaling to eliminate an offset reference can be made to commonly owned <CIT> and entitled "ROBOTIC SURGICAL SYSTEMS WITH ROLL, PITCH, AND YAW REALIGNMENT INCLUDING TRIM AND FLIP ALGORITHMS.

Slipping a position of the input handle <NUM> relative to a pose of the tool <NUM> allows for movement or repositioning of the input handle <NUM> within the workspace of the user interface <NUM> without movement of the tool <NUM> within the surgical site "S". The methods of collision recovery detailed above, e.g., moving the input handle <NUM> through a dead zone, operating with an offset, and dynamically scaling to eliminate offset, allows for predictable movement of a tool, e.g., tool <NUM>, of a surgical robot after a collision. Such predictable movement may improve surgical outcomes, reduce the surgical time, reduce recovery time, and/or reduce the cost of surgery.

As detailed above, the user interface <NUM> is in operable communication with the surgical robot <NUM> to perform a surgical procedure on a patient; however, it is envisioned that the user interface <NUM> may be in operable communication with a surgical simulator (not shown) to virtually actuate a robotic system and/or tool in a simulated environment. For example, the robotic surgical system <NUM> may have a first mode in which the user interface <NUM> is coupled to actuate the surgical robot <NUM> and a second mode in which the user interface <NUM> is coupled to the surgical simulator to virtually actuate a robotic system. The surgical simulator may be a standalone unit or be integrated into the processing unit <NUM>. The surgical simulator virtually responds to a clinician interfacing with the user interface <NUM> by providing visual, audible, force, and/or haptic feedback to a clinician through the user interface <NUM>. For example, as a clinician interfaces with the input handles <NUM>, the surgical simulator moves representative tools that are virtually acting on tissue. It is envisioned that the surgical simulator may allow a clinician to practice a surgical procedure before performing the surgical procedure on a patient. In addition, the surgical simulator may be used to train a clinician on a surgical procedure. Further, the surgical simulator may simulate "complications" during a proposed surgical procedure to permit a clinician to plan a surgical procedure.

Claim 1:
A processing unit of a robotic surgical system configured to perform a method of collision handling of a robotic surgical system with a processing unit of the robotic surgical system, the method comprising:
receiving (<NUM>) a first input signal from a user interface of the robotic surgical system to move a tool of a surgical robot of the robotic surgical system to a desired pose of the tool;
transmitting (<NUM>) an input control signal to the surgical robot to move the tool towards the desired pose;
receiving (<NUM>) a feedback signal from the surgical robot that a force to move the tool towards the desired pose is greater than a predetermined threshold;
maintaining (<NUM>) the tool at a threshold pose when the predetermined threshold is reached; and
slipping (<NUM>) a position of the input handle relative to the threshold pose to a second position of the input handle to define an offset between the second position of the input handle and a desired pose of the tool corresponding to the second position of the input handle further comprising
receiving (<NUM>) a second input signal from the user interface after slipping the position of the input handle indicative of the input handle moving towards a threshold position corresponding to the threshold pose of the tool further comprising
transmitting (<NUM>) a second control signal to the surgical robot to move the tool away from the desired pose with a trim defined between the input handle and the pose of the tool further comprising
dynamically scaling movement of the input handle to the pose of the tool to reduce the trim between the position of the input handle and the pose of the tool until the trim reaches a predetermined value.