Patent Description:
Various robotic systems have recently been developed to assist in MIS procedures and facilitate more instinctive hand movements by maintaining natural eye-hand axis. Such robotic systems can also allow for more degrees of freedom in movement by including an articulable "wrist" joint in the surgical tool that creates a more natural hand-like articulation. In such systems, an end effector positioned at the distal end of the surgical tool can be articulated (moved) using a cable driven motion system having one or more drive cables (or other elongate members) that extend through the wrist joint. A user (e.g., a surgeon) is able to remotely operate the end effector by grasping and manipulating in space one or more controllers that communicate with a tool driver coupled to the surgical instrument. User inputs are processed by a computer system incorporated into the robotic surgical system, and the tool driver responds by actuating the cable driven motion system and thereby actively controlling the tension balance in the drive cables. Moving the drive cables articulates the end effector to desired angular positions and configurations.

A number of mechanical and manufacturing hurdles must be overcome through component design and assembly to enable consistent and predictable performance of the end effector and its associated cable driven motion system. The disclosure of <CIT> provides a medical instrument including a shaft and an actuated structure mounted at a distal end of the shaft. The medical instrument can employ a pair of tendons connected to the actuated structure, extending down the shaft, and respectively wound around a capstan in opposite directions. A preload system may be coupled to maintain minimum tensions in the tendons. The disclosure of <CIT> provides a compact cable tension tender device including a movable member having a first stop and a second stop spaced apart from the first stop. A first attachment may be provided on the moveable member for cable that extends in a first direction. The first attachment may engage the first stop to limit the movement of the cable in the first direction relative to the movable member. A second attachment may be provided on the moveable member for cable that extends in a second direction. The second attachment may engage the second stop to limit the movement of the cable in the second direction relative to the movable member. A resilient coupler coupled to the first attachment and to the second attachment may urge the first attachment to move in the second direction and the second attachment to move in the first direction relative to each other to maintain cable tension. In the disclosure of <CIT>, a first pulley rotates around a rotation shaft. A first wire is wound around the first pulley. A second pulley is combined with the rotation shaft. The n first holes and m second holes are formed on opposite surfaces to the first and second pulleys. A fixing hole is formed by combining the first hole with the second hole. A fixing pin is inserted into the fixing hole. The n is a natural number. The m is the natural number except the n.

The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.

The present disclosure is related to robotic surgical systems and, more particularly, to capstan drive assemblies designed to eliminate slack in drive cables by ensuring a minimum cable tension is maintained.

Embodiments discussed herein describe surgical tools that include a drive housing having an elongate shaft extending therefrom and an end effector operatively coupled to a distal end of the elongate shaft. A drive input and input shaft are rotatably mounted to the drive housing, and a drive assembly is mounted to the input shaft and includes an upper capstan rotatably mounted to the input shaft with a first one-way bearing, and a lower capstan rotatably mounted to the input shaft with a second one-way bearing. A first drive cable is coupled to the upper capstan and extends to the end effector, and a second drive cable is coupled to the lower capstan and extends to the end effector. Rotating the input shaft in a first angular direction rotationally disengages the lower capstan from the input shaft and drives the upper capstan in the first angular direction to pull the first drive cable in a first linear direction. Rotating the input shaft in a second angular direction opposite the first angular direction rotationally disengages the upper capstan from the input shaft and drives the lower capstan in the second angular direction to pull the second drive cable in a second linear direction opposite the first linear direction.

<FIG> illustrate the structure and operation of an example robotic surgical system and associated components thereof. While applicable to robotic surgical systems, it is noted that the principles of the present disclosure may equally or alternatively be applied to non-robotic surgical systems, without departing from the scope of the disclosure.

<FIG> is a block diagram of an example robotic surgical system <NUM> that may incorporate some or all of the principles of the present disclosure. As illustrated, the system <NUM> can include at least one master control console 102a and at least one robotic manipulator <NUM>. The robotic manipulator <NUM> may be mechanically and/or electrically coupled to or otherwise include one or more robotic arms <NUM>. In some embodiments, the robotic manipulator <NUM> may be mounted to a transport cart (alternately referred to as an "arm cart") that enables mobility of the robotic manipulator <NUM> and the associated robotic arms <NUM>. Each robotic arm <NUM> may include and otherwise provide a tool driver where one or more surgical instruments or tools <NUM> may be mounted for performing various surgical tasks on a patient <NUM>. Operation of the robotic arms <NUM>, the corresponding tool drivers, and the associated tools <NUM> may be directed by a clinician 112a (e.g., a surgeon) from the master control console 102a.

In some embodiments, a second master control console 102b (shown in dashed lines) operated by a second clinician 112b may also help direct operation of the robotic arms <NUM> and the tools <NUM> in conjunction with the first clinician 112a. In such embodiments, for example, each clinician 112a,b may control different robotic arms <NUM> or, in some cases, complete control of the robotic arms <NUM> may be passed between the clinicians 112a,b. In some embodiments, additional robotic manipulators having additional robotic arms may be utilized during surgery on a patient <NUM>, and these additional robotic arms may be controlled by one or more of the master control consoles 102a,b.

The robotic manipulator <NUM> and the master control consoles 102a,b may communicate with one another via a communications link <NUM>, which may be any type of wired or wireless communications link configured to carry suitable types of signals (e.g., electrical, optical, infrared, etc.) according to any communications protocol. The communications link <NUM> may be an actual physical link or it may be a logical link that uses one or more actual physical links. When the link is a logical link the type of physical link may be a data link, uplink, downlink, fiber optic link, point-to-point link, for example, as is well known in the computer networking art to refer to the communications facilities that connect nodes of a network. Accordingly, the clinicians 112a,b may be able to remotely control the robotic arms <NUM> via the communications link <NUM>, thus enabling the clinicians 112a,b to operate on the patient <NUM> remotely.

<FIG> is one example embodiment of the master control console 102a that may be used to control operation of the robotic manipulator <NUM> of <FIG>. As illustrated, the master control console 102a can include a support <NUM> on which the clinician 112a,b (<FIG>) can rest his/her forearms while gripping one or more user input devices (not shown). The user input devices can comprise, for example, physical controllers such as, but not limited to, a joystick, exoskeletal gloves, a master manipulator, etc., and may be movable in multiple degrees of freedom to control the position and operation of the surgical tool(s) <NUM> (<FIG>). In some embodiments, the master control console 102a may further include one or more foot pedals <NUM> engageable by the clinician 112a,b to change the configuration of the surgical system and/or generate additional control signals to control operation of the surgical tool(s) <NUM>.

The user input devices and/or the foot pedals <NUM> may be manipulated while the clinician 112a,b (<FIG>) views the procedure via a visual display <NUM>. Images displayed on the visual display <NUM> may be obtained from an endoscopic camera or "endoscope. " In some embodiments, the visual display <NUM> may include or otherwise incorporate a force feedback meter or "force indicator" that provides the clinician 112a,b with a visual indication of the magnitude of force being assumed by the surgical tool (i.e., a cutting instrument or dynamic clamping member) and in which direction. As will be appreciated, other sensor arrangements may be employed to provide the master control console 102a with an indication of other surgical tool metrics, such as whether a staple cartridge has been loaded into an end effector or whether an anvil has been moved to a closed position prior to firing, for example.

<FIG> depicts one example of the robotic manipulator <NUM> that may be used to operate a plurality of surgical tools <NUM>, according to one or more embodiments. As illustrated, the robotic manipulator <NUM> may include a base <NUM> that supports a vertically extending column <NUM>. A plurality of robotic arms <NUM> (three shown) may be operatively coupled to the column <NUM> at a carriage <NUM> that can be selectively adjusted to vary the height of the robotic arms <NUM> relative to the base <NUM>, as indicated by the arrow A.

The robotic arms <NUM> may comprise manually articulable linkages, alternately referred to as "set-up joints. " In the illustrated embodiment, a surgical tool <NUM> is mounted to corresponding tool drivers <NUM> provided on each robotic arm <NUM>. Each tool driver <NUM> may include one or more drivers or motors used to interact with a corresponding one or more drive inputs of the surgical tools <NUM>, and actuation of the drive inputs causes the associated surgical tool <NUM> to operate.

One of the surgical tools <NUM> may comprise an image capture device <NUM>, such as an endoscope, which may include, for example, a laparoscope, an arthroscope, a hysteroscope, or may alternatively include some other imaging modality, such as ultrasound, infrared, fluoroscopy, magnetic resonance imaging, or the like. The image capture device <NUM> has a viewing end located at the distal end of an elongate shaft, which permits the viewing end to be inserted through an entry port into an internal surgical site of a patient's body. The image capture device <NUM> may be communicably coupled to the visual display <NUM> (<FIG>) and capable of transmitting images in real-time to be displayed on the visual display <NUM>.

The remaining surgical tools may be communicably coupled to the user input devices held by the clinician 112a,b (<FIG>) at the master control console 102a (<FIG>). Movement of the robotic arms <NUM> and associated surgical tools <NUM> may be controlled by the clinician 112a,b manipulating the user input devices. As described in more detail below, the surgical tools <NUM> may include or otherwise incorporate an end effector mounted on a corresponding articulable wrist pivotally mounted on a distal end of an associated elongate shaft. The elongate shaft permits the end effector to be inserted through entry ports into the internal surgical site of a patient's body, and the user input devices also control movement (actuation) of the end effector.

In use, the robotic manipulator <NUM> is positioned close to a patient requiring surgery and is then normally caused to remain stationary until a surgical procedure to be performed has been completed. The robotic manipulator <NUM> typically has wheels or castors to render it mobile. The lateral and vertical positioning of the robotic arms <NUM> may be set by the clinician 112a,b (<FIG>) to facilitate passing the elongate shafts of the surgical tools <NUM> and the image capture device <NUM> through the entry ports to desired positions relative to the surgical site. When the surgical tools <NUM> and image capture device <NUM> are so positioned, the robotic arms <NUM> and carriage <NUM> can be locked in position.

<FIG> is an isometric side view of an example surgical tool <NUM> that may incorporate some or all of the principles of the present disclosure. The surgical tool <NUM> may be the same as or similar to the surgical tool(s) <NUM> of <FIG> and <FIG> and, therefore, may be used in conjunction with a robotic surgical system, such as the robotic surgical system <NUM> of <FIG>. Accordingly, the surgical tool <NUM> may be designed to be releasably coupled to a tool driver included in the robotic surgical system <NUM>. In other embodiments, however, aspects of the surgical tool <NUM> may be adapted for use in a manual or hand-operated manner, without departing from the scope of the disclosure.

As illustrated, the surgical tool <NUM> includes an elongated shaft <NUM>, an end effector <NUM>, a wrist <NUM> (alternately referred to as a "wrist joint" or an "articulable wrist joint") that couples the end effector <NUM> to the distal end of the shaft <NUM>, and a drive housing <NUM> coupled to the proximal end of the shaft <NUM>. In applications where the surgical tool is used in conjunction with a robotic surgical system (e.g., the robotic surgical system <NUM> of <FIG>), the drive housing <NUM> can include coupling features that releasably couple the surgical tool <NUM> to the robotic surgical system.

The terms "proximal" and "distal" are defined herein relative to a robotic surgical system having an interface configured to mechanically and electrically couple the surgical tool <NUM> (e.g., the housing <NUM>) to a robotic manipulator. The term "proximal" refers to the position of an element closer to the robotic manipulator and the term "distal" refers to the position of an element closer to the end effector <NUM> and thus further away from the robotic manipulator. Alternatively, in manual or hand-operated applications, the terms "proximal" and "distal" are defined herein relative to a user, such as a surgeon or clinician. The term "proximal" refers to the position of an element closer to the user and the term "distal" refers to the position of an element closer to the end effector <NUM> and thus further away from the user. Moreover, the use of directional terms such as above, below, upper, lower, upward, downward, left, right, and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward or upper direction being toward the top of the corresponding figure and the downward or lower direction being toward the bottom of the corresponding figure.

During use of the surgical tool <NUM>, the end effector <NUM> is configured to move (pivot) relative to the shaft <NUM> at the wrist <NUM> to position the end effector <NUM> at desired orientations and locations relative to a surgical site. To accomplish this, the housing <NUM> includes (contains) various drive inputs and mechanisms (e.g., gears, actuators, etc.) designed to control operation of various features associated with the end effector <NUM> (e.g., clamping, firing, rotation, articulation, cutting, etc.). In at least some embodiments, the shaft <NUM>, and hence the end effector <NUM> coupled thereto, is configured to rotate about a longitudinal axis A<NUM> of the shaft <NUM>. In such embodiments, at least one of the drive inputs included in the housing <NUM> is configured to control rotational movement of the shaft <NUM> about the longitudinal axis A<NUM>.

The surgical tool <NUM> can have any of a variety of configurations capable of performing at least one surgical function. For example, the surgical tool <NUM> may include, but is not limited to, forceps, a grasper, a needle driver, scissors, an electro cautery tool, a stapler, a clip applier, a hook, a spatula, a suction tool, an irrigation tool, an imaging device (e.g., an endoscope or ultrasonic probe), or any combination thereof. In some embodiments, the surgical tool <NUM> may be configured to apply energy to tissue, such as radio frequency (RF) energy. In the illustrated embodiment, the end effector <NUM> comprises a tissue grasper and vessel sealer that include opposing jaws <NUM>, <NUM> configured to move (articulate) between open and closed positions. As will be appreciated, however, the opposing jaws <NUM>, <NUM> may alternatively form part of other types of end effectors such as, but not limited to, a surgical scissors, a clip applier, a needle driver, a babcock including a pair of opposed grasping jaws, bipolar jaws (e.g., bipolar Maryland grasper, forceps, a fenestrated grasper, etc.), etc. One or both of the jaws <NUM>, <NUM> may be configured to pivot to articulate the end effector <NUM> between the open and closed positions.

The shaft <NUM> is an elongate member extending distally from the housing <NUM> and has at least one lumen extending therethrough along its axial length. In some embodiments, the shaft <NUM> may be fixed to the housing <NUM>, but could alternatively be rotatably mounted to the housing <NUM> to allow the shaft <NUM> to rotate about the longitudinal axis A<NUM>. In yet other embodiments, the shaft <NUM> may be releasably coupled to the housing <NUM>, which may allow a single housing <NUM> to be adaptable to various shafts having different end effectors.

<FIG> illustrates the potential degrees of freedom in which the wrist <NUM> may be able to articulate (pivot). The wrist <NUM> can have any of a variety of configurations. In general, the wrist <NUM> comprises a joint configured to allow pivoting movement of the end effector <NUM> relative to the shaft <NUM>. The degrees of freedom of the wrist <NUM> are represented by three translational variables (i.e., surge, heave, and sway), and by three rotational variables (i.e., Euler angles or roll, pitch, and yaw). The translational and rotational variables describe the position and orientation of a component of a surgical system (e.g., the end effector <NUM>) with respect to a given reference Cartesian frame. As depicted in <FIG>, "surge" refers to forward and backward translational movement, "heave" refers to translational movement up and down, and "sway" refers to translational movement left and right. With regard to the rotational terms, "roll" refers to tilting side to side, "pitch" refers to tilting forward and backward, and "yaw" refers to turning left and right.

The pivoting motion can include pitch movement about a first axis of the wrist <NUM> (e.g., X-axis), yaw movement about a second axis of the wrist <NUM> (e.g., Y-axis), and combinations thereof to allow for <NUM>° rotational movement of the end effector <NUM> about the wrist <NUM>. In other applications, the pivoting motion can be limited to movement in a single plane, e.g., only pitch movement about the first axis of the wrist <NUM> or only yaw movement about the second axis of the wrist <NUM>, such that the end effector <NUM> moves only in a single plane.

Referring again to <FIG>, the surgical tool <NUM> may also include a plurality of drive cables (obscured in <FIG>) that form part of a cable driven motion system configured to facilitate movement and articulation of the end effector <NUM> relative to the shaft <NUM>. Moving (actuating) at least some of the drive cables moves the end effector <NUM> between an unarticulated position and an articulated position. The end effector <NUM> is depicted in <FIG> in the unarticulated position where a longitudinal axis A<NUM> of the end effector <NUM> is substantially aligned with the longitudinal axis A<NUM> of the shaft <NUM>, such that the end effector <NUM> is at a substantially zero angle relative to the shaft <NUM>. In the articulated position, the longitudinal axes A<NUM>, A<NUM> would be angularly offset from each other such that the end effector <NUM> is at a non-zero angle relative to the shaft <NUM>.

In some embodiments, the surgical tool <NUM> may be supplied with electrical power (current) via a power cable <NUM> coupled to the housing <NUM>. In other embodiments, the power cable <NUM> may be omitted and electrical power may be supplied to the surgical tool <NUM> via an internal power source, such as one or more batteries or fuel cells. In such embodiments, the surgical tool <NUM> may alternatively be characterized and otherwise referred to herein as an "electrosurgical instrument" capable of providing electrical energy to the end effector <NUM>.

The power cable <NUM> may place the surgical tool <NUM> in communication with a generator <NUM> that supplies energy, such as electrical energy (e.g., radio frequency energy), ultrasonic energy, microwave energy, heat energy, or any combination thereof, to the surgical tool <NUM> and, more particularly, to the end effector <NUM> to cauterize and/or coagulate tissue. Accordingly, the generator <NUM> may comprise a radio frequency (RF) source, an ultrasonic source, a direct current source, and/or any other suitable type of electrical energy source that may be activated independently or simultaneously.

<FIG> is an enlarged isometric view of the distal end of the surgical tool <NUM> of <FIG>. More specifically, <FIG> depicts enlarged views of the end effector <NUM> and the wrist <NUM>, with the jaws <NUM>, <NUM> of the end effector <NUM> in the open position. The wrist <NUM> operatively couples the end effector <NUM> to the shaft <NUM>. In some embodiments, however, a shaft adapter may be directly coupled to the wrist <NUM> and otherwise interpose the shaft <NUM> and the wrist <NUM>. Accordingly, the wrist <NUM> may be operatively coupled to the shaft <NUM> either through a direct coupling engagement where the wrist <NUM> is directly coupled to the distal end of the shaft <NUM>, or an indirect coupling engagement where a shaft adapter interposes the wrist <NUM> and the distal end of the shaft <NUM>. As used herein, the term "operatively couple" refers to a direct or indirect coupling engagement.

To operatively couple the end effector <NUM> to the shaft <NUM>, the wrist <NUM> includes a first or "distal" linkage 602a, a second or "intermediate" linkage 602b, and a third or "proximal" linkage 602c. The linkages 602a-c are configured to facilitate articulation of the end effector <NUM> relative to the shaft <NUM>, e.g., angle the end effector <NUM> relative to the longitudinal axis A<NUM> (<FIG>) of the shaft <NUM>. In the illustrated embodiment, articulation via the linkages 602a-c may be limited to pitch only, yaw only, or a combination thereof. As illustrated, the distal linkage 602a may be coupled to the end effector <NUM> and, more particularly, to the lower jaw <NUM> (or an extension of the lower jaw <NUM>). The distal linkage 602a may also be rotatably coupled to the intermediate linkage 602b at a first axle 604a, and the intermediate linkage 602b may be rotatably coupled to the proximal linkage 602c at a second axle 604b. The proximal linkage 602c may then be coupled to a distal end <NUM> of the shaft <NUM> (or alternatively a shaft adapter).

The wrist <NUM> provides a first pivot axis P<NUM> that extends through the first axle 604a and a second pivot axis P<NUM> that extends through the second axle 604b. The first pivot axis P<NUM> is substantially perpendicular (orthogonal) to the longitudinal axis A<NUM> (<FIG>) of the end effector <NUM>, and the second pivot axis P<NUM> is substantially perpendicular (orthogonal) to both the longitudinal axis A<NUM> and the first pivot axis P<NUM>. Movement about the first pivot axis P<NUM> provides "yaw" articulation of the end effector <NUM>, and movement about the second pivot axis P<NUM> provides "pitch" articulation of the end effector <NUM>. Alternatively, the first pivot axis P<NUM> could be configured to provide "pitch" articulation and the second pivot axis P<NUM> could be configured to provide "yaw" articulation.

A plurality of drive cables, shown as drive cables 608a, 608b, 608c, and 608d, extend longitudinally within a lumen <NUM> defined by the shaft <NUM> (and/or a shaft adaptor) and pass through the wrist <NUM> to be operatively coupled to the end effector <NUM>. The lumen <NUM> can be a single lumen, as illustrated, or can alternatively comprise a plurality of independent lumens that each receive one or more of the drive cables 608a-d.

The drive cables 608a-d form part of the cable driven motion system briefly described above, and may be referred to and otherwise characterized as cables, bands, lines, cords, wires, ropes, strings, twisted strings, elongate members, etc. The drive cables 608a-d can be made from a variety of materials including, but not limited to, metal (e.g., tungsten, stainless steel, etc.), a polymer (e.g., ultra-high molecular weight polyethylene), a synthetic fiber (e.g., KEVLAR®, VECTRAN®, etc.), or any combination thereof. While four drive cables 608a-d are depicted in <FIG>, more or less than four drive cables 608a-d may be included, without departing from the scope of the disclosure.

The drive cables 608a-d extend proximally from the end effector <NUM> to the drive housing <NUM> (<FIG>) where they are operatively coupled to various actuation mechanisms (e.g., capstans) or devices housed therein to facilitate longitudinal movement (translation) of the drive cables 608a-d within the lumen <NUM>. Selective actuation of all or a portion of the drive cables 608a-d causes the end effector <NUM> to articulate (pivot) relative to the shaft <NUM>. More specifically, selective actuation causes a corresponding drive cable 608a-d to translate longitudinally within the lumen <NUM> and thereby cause pivoting movement of the end effector <NUM> at the wrist <NUM>. Moving the drive cables 608a-d can be accomplished in a variety of ways, such as by triggering an associated actuator or mechanism (e.g., a capstan) operatively coupled to or housed within the drive housing <NUM> (<FIG>). Moving a given drive cable 608a-d constitutes applying tension (i.e., pull force) to the given drive cable 608a-d in a proximal direction, which causes the given drive cable 608a-d to translate and thereby cause the end effector <NUM> to move (articulate) relative to the shaft <NUM>. As will be appreciated, applying tension to and moving one drive cable 608a-d may result in the slackening of a drive cable 608a-d angularly (or diagonally) opposite to the moving drive cable 608a-d. Embodiments of the present disclosure may be configured to mitigate this occurrence.

The drive cables 608a-d each extend longitudinally through the first, second, and third linkages 602a-c and terminate at the first linkage 602a, thus operatively coupling each drive cable 608a-d to the end effector <NUM> and, more particularly, to the lower jaw <NUM>. In some embodiments, as illustrated, the distal end of each drive cable 608a-d may include a ball crimp <NUM> (only one shown). In other embodiments, the distal end of each drive cable 608a-d may include a weld, an adhesive attachment, a press fit, or any combination of the foregoing.

In some embodiments, an electrical conductor <NUM> may supply electrical energy to the end effector <NUM> and, more particularly, to an electrode <NUM> included in the end effector <NUM>. The electrical conductor <NUM> extends longitudinally within the lumen <NUM>, through the wrist <NUM>, and terminates at the electrode <NUM>. The end effector <NUM> may be configured for monopolar or bipolar operation. In the illustrated embodiment, the electrode <NUM> is mounted to or otherwise forms part of the lower jaw <NUM>. In other embodiments, however, the electrode <NUM> may form part of the upper jaw <NUM>, or may alternatively be coupled to or form part of both jaws <NUM>, <NUM>. In some embodiments, the electrical conductor <NUM> and the power cable <NUM> (<FIG>) may comprise the same structure. In other embodiments, however, the electrical conductor <NUM> may be electrically coupled to the power cable <NUM>. In yet other embodiments, the electrical conductor <NUM> may extend to the drive housing <NUM> where it is electrically coupled to an internal power source, such as batteries or fuel cells.

In the illustrated embodiment, the end effector <NUM> comprises a vessel sealer that includes a knife or "cutting element" <NUM> (mostly occluded) configured to advance and retract within a groove or slot <NUM> defined longitudinally in one or both of the upper and lower jaws <NUM>, <NUM>. In example operation, the jaws <NUM>, <NUM> may be actuated to close and grasp onto tissue, following which the cutting element <NUM> may be advanced distally along the slot(s) <NUM> to cut the grasped tissue. Alternatively, the cutting element <NUM> may be deployed after the application of electrical energy to transect coagulated tissue.

The jaws <NUM>, <NUM> may be moved between the closed and open positions by pivoting the upper jaw <NUM> relative to the lower jaw <NUM>. In the illustrated embodiment, the upper jaw <NUM> may be rotatably coupled (mounted) to the lower jaw <NUM> at a jaw axle <NUM>. A third pivot axis P<NUM> extends through the jaw axle <NUM> and is generally perpendicular (orthogonal) to the first pivot axis P<NUM> and parallel to the second pivot axis P<NUM>. A central pulley <NUM> (partially visible) may be mounted to the jaw axle <NUM> and receive a jaw cable <NUM> that may be actuated to selectively open and close the jaws <NUM>, <NUM>.

Similar to the drive cables 608a-d, the jaw cable <NUM> extends longitudinally within the lumen <NUM> and passes through the wrist <NUM>. Moreover, the jaw cable <NUM> may form part of the cable driven motion system described herein and, therefore, may extend proximally from the end effector <NUM> to the drive housing <NUM> (<FIG>). In some embodiments, the jaw cable <NUM> comprises two lines or wires connected at or near the central pulley <NUM> and extending proximally to the drive housing <NUM>. In other embodiments, however, the jaw cable <NUM> may comprise a single line or wire looped around the central pulley <NUM> and opposing first and second ends 628a and 628b of the jaw cable <NUM> extend proximally to the drive housing <NUM>.

<FIG> is a bottom view of the drive housing <NUM>, according to one or more embodiments. As illustrated, the drive housing <NUM> may include a tool mounting interface <NUM> used to operatively couple the drive housing <NUM> to a tool driver of a robotic manipulator (e.g., the robotic manipulators <NUM>, <NUM> of <FIG> and <FIG>, respectively). The tool mounting interface <NUM> may releasably couple the drive housing <NUM> to a tool driver in a variety of ways, such as by clamping thereto, clipping thereto, or slidably mating therewith. The tool mounting interface <NUM> may include an array of electrical connecting pins, which may be coupled to an electrical connection on the mounting surface of the tool driver. Accordingly, the tool mounting interface <NUM> may mechanically, magnetically, and/or electrically couple the drive housing <NUM> to the tool driver.

As illustrated, the interface <NUM> includes and supports a plurality of inputs, shown as drive inputs 704a, 704b, 704c, 704d, 704e, and 704f. Each drive input 704a-f may comprise a rotatable disc configured to align with and couple to a corresponding actuator of a given tool driver. Each drive input 704a-f may provide or define one or more surface features <NUM> configured to align and mate with corresponding features provided on the given actuator. The surface features <NUM> can include, for example, various protrusions and/or indentations that facilitate a mating engagement. Each of the drive inputs 704a-f may be actuated based on user inputs communicated to a tool driver coupled to the interface <NUM>, and the user inputs may be received via a computer system incorporated into the robotic surgical system.

In some embodiments, actuation of the first drive input 704a may be configured to control rotation of the shaft <NUM> about its longitudinal axis A<NUM>. The shaft <NUM> may be rotated clockwise or counter-clockwise depending on the rotational direction of the first drive input 704a. In some embodiments, actuation of the second drive input 704b may be configured to advance or retract the cutting element <NUM> (<FIG>). In some embodiments, actuation of the third and fourth drive inputs 704c,d may be configured to open and close the jaws <NUM>, <NUM> (<FIG> and <FIG>). More specifically, the first and second ends 628a,b (<FIG>) of the jaw cable <NUM> (<FIG>) may extend to and be operatively coupled to a corresponding one of the third and fourth drive inputs 704c,d such that cooperative actuation of the third and fourth drive inputs 704c,d causes the jaw cable <NUM> to open/close the jaws <NUM>, <NUM>.

In some embodiments, actuation of the fifth and sixth drive inputs 704e,f may be configured to axially translate the drive cables 608a-d (<FIG>), and thereby articulate the end effector <NUM> (<FIG> and <FIG>). More specifically, two drive cables 608a-d may be operatively coupled to each drive input 704e,f such that actuation of the fifth drive input 704e causes two drive cables 608a-d to axially translate, and actuation of the sixth drive input 704f causes the other two drive cables 608a-d to axially translate. In one embodiment, for example, the second and third drive cables 608b,c may be driven by actuation of the fifth drive input 704e, and the first and fourth drive cables 608a,d may be driven by actuation of the sixth drive input 704e.

<FIG> is an isometric exposed view of the interior of the drive housing <NUM>, according to one or more embodiments. Several component parts that would otherwise be contained within the drive housing <NUM> are not shown in <FIG> to enable discussion of the depicted component parts. More particularly, <FIG> depicts a drive assembly <NUM> associated with the sixth drive input 704f (<FIG>), and several holes <NUM> are defined in the drive housing <NUM> where additional drive assemblies (not shown) would otherwise be mounted to the drive housing <NUM> and associated with the first - fifth drive inputs 704a-e, respectively.

The drive assembly <NUM> may include or otherwise be mounted to an input shaft <NUM>. The input shaft <NUM> is operatively coupled to or otherwise extends from the sixth drive input 704f (<FIG>) such that actuation of the sixth drive input 704f correspondingly rotates the input shaft <NUM>.

The drive assembly <NUM> may also include a first or "upper" capstan assembly 806a and a second or "lower" capstan assembly 806b, and each capstan assembly 806a,b may be rotatably mounted to the input shaft <NUM>. The upper capstan assembly 806a includes a first or "upper" capstan 808a and the lower capstan assembly 806b includes a second or "lower" capstan 808b. Each of the capstans 808a,b may have a drive cable coupled thereto (i.e., wrapped thereabout) and extending therefrom. In the illustrated embodiment, the first drive cable 608a (shown as dashed line) is coupled to the upper capstan 808a and the fourth drive cable 608d (shown as dashed line) is coupled to the lower capstan 808a. Each drive cable 608a,d extends from the corresponding capstan 808a,b and out of the drive housing <NUM>. As will be appreciated, the first and fourth drive cables 604cables 608a,d may alternatively be coupled to the opposite capstan 808a,b, without departing from the scope of the disclosure. Moreover, any combination of two of the drive cables 608a-d of <FIG> may be coupled to the capstans 808a,b, in accordance with this disclosure.

The upper capstan 808a may be operatively coupled to the input shaft <NUM> such that rotating the input shaft <NUM> in a first angular direction 810a (e.g., clockwise) correspondingly drives the upper capstan 808a in the first angular direction 810a, which causes the first drive cable 608a to be pulled in a first linear direction 812a (e.g., proximally) and correspondingly wrap about the upper capstan 808a. Moreover, rotating the input shaft <NUM> in the first angular direction 810a will rotationally disengage the lower capstan 808b from the input shaft <NUM> and allow the input shaft <NUM> to rotate relative to the lower capstan 808b. Consequently, when the input shaft <NUM> is rotated in the first angular direction 810a, the fourth drive cable 608d may be allowed to move in a second linear direction 812b (e.g., distally) opposite the first linear direction 812a, if needed, and may otherwise unwrap from the lower capstan 808b to help maintain adequate tensile load. In at least one embodiment, the length (linear distance) of the first drive cable 608a wrapped onto the upper capstan 808a when the input shaft <NUM> rotates in the first angular direction 810a may be substantially the same length (linear distance) of the fourth drive cable 608d unwrapped from the lower capstan 808b.

Conversely, the lower capstan 808b may be operatively coupled to the input shaft <NUM> such that rotating the input shaft <NUM> in a second angular direction 810b (e.g., counter-clockwise) opposite the first angular direction 810a correspondingly drives the lower capstan 808b in the second angular direction 810a, which causes the fourth drive cable 608d to be pulled in the second linear direction 812b and correspondingly wrap about the lower capstan 808b. Moreover, rotating the input shaft <NUM> in the second angular direction 810b will rotationally disengage the upper capstan 808a from the input shaft <NUM>, thus allowing the input shaft <NUM> to rotate relative to the upper capstan 808a. Consequently, when the input shaft <NUM> is rotated in the second angular direction 810b, the first drive cable 608a may be allowed to move in the second linear direction 812b, if needed, and may otherwise unwrap from the upper capstan 808a to help maintain adequate tensile load. In at least one embodiment, the length (linear distance) of the fourth drive cable 608b wrapped onto the lower capstan 808b when the input shaft <NUM> rotates in the second angular direction 810b may be substantially the same length (linear distance) of the first drive cable 608a unwrapped from the upper capstan 808a.

<FIG> are enlarged isometric and exploded views of the drive assembly <NUM>, according to one or more embodiments of the disclosure. As illustrated, the input shaft <NUM> comprises a generally elongate body having a first or upper end 902a and a second or lower end 902b opposite the upper end 902a. The sixth drive input 704f may be operatively coupled to the lower end 902b. In some embodiments, for example the sixth drive input 704f may be mechanically fastened to the lower end 902b, such as with a screw or the like. Alternatively, the input shaft <NUM> may form an integral extension of the sixth drive input 704f. The drive assembly <NUM> may also include a flanged bushing 904a configured to help rotatably mount the sixth drive input 704f to the drive housing <NUM> (<FIG>, <FIG>). The flanged bushing 904a, however, may be optional.

In the illustrated embodiment, the upper capstan assembly 806a may include the upper capstan 808a, an adapter or housing <NUM>, and a first one-way bearing 908a (best seen in <FIG>). As illustrated, the upper capstan 808a includes a first helical groove 910a that extends about the outer circumference of at least a portion of the upper capstan 808a. The first helical groove 910a may be configured to receive a drive cable, such as the first drive cable 608a (<FIG> and <FIG>), as described above. The end of the first drive cable 608a may be fixedly attached to the upper capstan 808a, and as the upper capstan 808a rotates, the first drive cable 608a may be paid out (i.e., unwrapped) or pulled in, depending on the rotational direction.

The upper capstan 808a may be matable with the adapter <NUM>. In some embodiments, as best seen in <FIG>, the upper capstan 808a may provide or otherwise define a first mating structure 912a and the adapter <NUM> may provide or otherwise define a second mating structure 912b (partially visible in <FIG>) matable with the first mating structure 912a. Upon appropriately mating the first and second mating structures 912a,b, the upper capstan 808a and the adapter <NUM> will rotate as a single, monolithic body. The first and second mating structures 912a,b may comprise any matable engagement that rotationally fixes the upper capstan 808a to the adapter <NUM>, and vice versa. In the illustrated embodiment, the first and second mating structures 912a,b are matable castellations or castellated (interlocking) features defined on each component part. In other embodiments, however, the first and second mating structures 912a,b may alternately comprise a dovetail engagement, a tongue and groove engagement, a pin or clip engaged with mating holes, a splined engagement, an interference or shrink fit engagement, welding, an adhesive bonding, or any combination thereof.

In at least one embodiment, the upper capstan assembly 806a may further include a flanged bushing 904b that may help the upper capstan 808a mate with the adapter <NUM>. In other embodiments, however, the flanged bushing 904b may be omitted, without departing from the scope of the disclosure. The flanged bushing 904b acts as a flanged plane bearing to mitigate friction between the upper capstan 808a and a frame structure (not illustrated) arranged within the drive housing <NUM> (<FIG>) to support the upper capstan 808a.

The adapter <NUM> may define a cavity <NUM> sized to receive the first one-way bearing 908a. The first one-way bearing 908a may comprise any type of bearing that allows rotation in one angular direction, but prevents rotation in the opposite direction. The first one-way bearing 908a may comprise, for example, a one-way clutch bearing, a sprag-style bearing, an anti-reverse bearing, or any combination thereof. In at least one embodiment, the first one-way bearing 908a may comprise a ratchet mechanism that allows rotation in a first direction but prohibits rotation in a second direction. The first one-way bearing 908a may be secured within the cavity <NUM> via a variety of attachment means including, but not limited to, an interference fit, a mechanical attachment, a weld, an adhesive, or any combination thereof. When the upper capstan assembly 806a is assembled on the input shaft <NUM>, an inner radial surface <NUM> of the first one-way bearing 908a may be positioned to engage an outer radial surface of the input shaft <NUM> at or near the upper end 902a.

Accordingly, in at least one embodiment, the upper capstan 808a may be rotatably mounted to the input shaft <NUM> via the adapter <NUM> and the first one-way bearing 908a. In other embodiments, however, the adapter <NUM> may be omitted from the upper capstan assembly 806a. In such embodiments, the first one-way bearing 908a may alternatively be secured to the upper capstan 808a.

In some embodiments, the first one-way bearing 908a may be non-rotatable in the first angular direction 810a, but may allow rotation in the second angular direction 810b. Consequently, when the input shaft <NUM> is rotated in the first angular direction 810a, the first one-way bearing 908a may bind against the input shaft <NUM> and transfer the torque from the input shaft <NUM> to the upper capstan 808a, and thereby drive the upper capstan 808a in the first angular direction 810a. As mentioned above, rotating the upper capstan 808a in the first angular direction 810a may cause the first drive cable 608a (<FIG> and <FIG>) to wrap about the upper capstan 808a. When the input shaft <NUM> is rotated in the second angular direction 810b, however, the first one-way bearing 908a may allow free motion that rotationally disengages the upper capstan 808a from the input shaft <NUM> and thereby allows the input shaft <NUM> to rotate relative to the upper capstan 808a.

The lower capstan assembly 806b may include the lower capstan 808b and a second one-way bearing 908b (best seen in <FIG>). As illustrated, the lower capstan 808b includes a second helical groove 910b that extends about the outer circumference of at least a portion of the lower capstan 808b. The second helical groove 910b may be configured to receive a drive cable, such as the fourth drive cable 608d (<FIG> and <FIG>), as described above. The end of the fourth drive cable 608d may be fixedly attached to the lower capstan 808b and, as the lower capstan 808b rotates, the fourth drive cable 608d may be paid out (i.e., unwrapped) or pulled in, depending on the rotational direction.

The second one-way bearing 908b may be operatively coupled to the lower capstan 808b. In one embodiment, for example, the second one-way bearing 908b may be received within a cavity (not shown) defined by the lower capstan 808b, and may be secured within the cavity via an interference fit, a mechanical attachment, a weld, an adhesive, or any combination thereof. When the lower capstan assembly 806b is assembled on the input shaft <NUM>, an inner radial surface <NUM> of the second one-way bearing 908b may be positioned to engage an outer radial surface of the input shaft <NUM> at or near the upper end 902a.

Similar to the first one-way bearing 908a, the second one-way bearing 908b may comprise any type of bearing that allows rotation in one angular direction, but prevents rotation in the opposite direction. In at least one embodiment, the first and second one-way bearings 908a,b may be the same type of bearing, but mounted oppositely such that the first and second capstans 808a,b are driven in rotation by opposite angular rotation of the input shaft <NUM>.

Accordingly, the lower capstan 808b may be rotatably mounted to the input shaft <NUM> via the second one-way bearing 908b. In some embodiments, the second one-way bearing 908b may be non-rotatable in the second angular direction 810b, but may allow rotation in the first angular direction 810a. Consequently, when the input shaft <NUM> is rotated in the second angular direction 810b, the second one-way bearing 908b may bind against the input shaft <NUM> and transfer the torque from the input shaft <NUM> to the lower capstan 808b, and thereby drive the lower capstan 808b in the second angular direction 810b. As mentioned above, rotating the lower capstan 808b in the second angular direction 810b may cause the fourth drive cable 608d (<FIG> and <FIG>) to wrap about the lower capstan 808b. When the input shaft <NUM> is rotated in the first angular direction 810a, however, the second one-way bearing 908b may allow free motion that rotationally disengages the lower capstan 808b from the input shaft <NUM> and allows the input shaft <NUM> to rotate relative to the lower capstan 808b.

The drive assembly <NUM> may further include a compliant member <NUM> operatively coupled to and extending between the upper and lower capstan assemblies 806a,b. In the illustrated embodiment, the compliant member <NUM> comprises a coil spring, but could alternatively comprise any other type of biasing device capable of transferring torque. For example, the compliant member <NUM> could alternately comprise a compression spring attached to each capstan assembly 806a,b with a cable. As illustrated, the compliant member <NUM> may have a first or upper end 922a engageable with the upper capstan assembly 806a, and a second or lower end 922b engageable with the lower capstan assembly 806b. In some embodiments, the upper end 922a may be configured to mate with a receiving feature (see <FIG>) defined on the adapter <NUM>. In other embodiments, however, the receiving feature may alternatively form part of the upper capstan 808a, without departing from the scope of the disclosure. Receiving the upper end 922a within the receiving feature may allow the compliant member <NUM> to transmit torque to the upper capstan assembly 806a and, more particularly, to the upper capstan 808a.

The lower end 922b of the compliant member <NUM> may be coupled to the lower capstan 808b. More particularly, the lower end 922b may extend laterally and be received within a slot <NUM> defined in the lower capstan 808b. In at least one embodiment, the bottom end of the upper capstan 808a may help keep the lower end 922b within the slot <NUM> when the drive assembly <NUM> is assembled. Receiving the lower end 922b within the slot <NUM> may allow the compliant member <NUM> to transmit torque to the lower capstan assembly 806b and, more particularly, to the lower capstan 808b.

<FIG> is an exploded isometric view of a portion of the drive assembly <NUM>, according to one or more embodiments. More specifically, <FIG> shows a bottom portion of the adapter <NUM>. As mentioned above, the adapter <NUM> may define the second mating structure 912b, which is matable with the first mating structure 912a of the upper capstan 808a. Moreover, the adapter <NUM> may provide or define a receiver feature <NUM> configured to receive and otherwise mate with the upper end 922a of the compliant member <NUM>. As illustrated, the receiver feature <NUM> may comprise a hole or cavity sized to receive the upper end 922a, but could alternatively comprise a slot or the like. In embodiments where the adapter <NUM> is omitted, however, the receiver feature <NUM> may alternatively be provided on the upper capstan 808a, or the upper end 922a of the compliant member <NUM> may otherwise be coupled directly to the upper capstan 808a and capable of transferring torsion to the upper capstan assembly 806a.

Referring again to <FIG>, the compliant member <NUM> may be configured to provide a constant amount of opposing torsional load on the upper and lower capstan assemblies 806a,b to help reduce the amount of cable slack that might develop in the drive cables coupled thereto. The compliant member <NUM> may be pretensioned during assembly of the drive assembly <NUM>, which causes the compliant member <NUM> to act on both the upper and lower capstan assemblies 806a,b in opposite angular directions and thereby urge the corresponding upper and lower capstans 808a,b to counter-rotate. In some embodiments, the torque provided by the compliant member <NUM> may be set at or below the pre-tension limit of the cables attached to the upper and lower capstans 808a,b. Consequently, if the tension in a given cable drops below the pre-tension value, the compliant member <NUM> will act on the corresponding capstan 808a,b and cause the capstan 808a,b to counter rotate and remove the slack.

During example operation, when the upper capstan 808a is rotated to pull on the first drive cable 608a (<FIG> and <FIG>), as described above, the tension on the fourth drive cable 608d (<FIG> and <FIG>) may slacken. The torsional load provided by the compliant member <NUM> on the lower capstan 808b, however, may counter-rotate the lower capstan 808b and thereby help remove this slack in the fourth drive cable 608d. Conversely, when the lower capstan 808b is rotated to pull on the fourth drive cable 608d, as described above, the tension on the first drive cable 608a may slacken, but the torsional load provided by the compliant member <NUM> on the upper capstan 808a may counter-rotate the upper capstan 808a and thereby help remove any slack developing in the first drive cable 608a. Accordingly, this creates a system that is very stiff when applying tension to cables, and the system is therefore able to resist external loads applied during a surgical procedure.

Claim 1:
A drive assembly (<NUM>) for a surgical tool, comprising:
a first capstan assembly (806a) including an upper capstan (808a) rotatably mountable to an input shaft (<NUM>) of the surgical tool with a first one-way bearing (908a);
a lower capstan assembly (806b) including a lower capstan (808b) rotatably mountable to the input shaft with a second one-way bearing (908b);
a compliant member (<NUM>) operatively coupled to and extending between the upper and lower capstan assemblies, wherein the compliant member provides constant opposing torsional loads on the upper and lower capstan assemblies that urge the upper and lower capstans to counter-rotate; and
a first drive cable (608a) securable to the upper capstan and extendable to an end effector (<NUM>) of the surgical tool, and a second drive cable (608d) securable to the lower capstan and extendable to the end effector,
wherein rotating the input shaft in a first angular direction (810a) rotationally disengages the lower capstan from the input shaft and drives the upper capstan in the first angular direction to wrap the first drive cable about the upper capstan,
wherein rotating the input shaft in a second angular direction (810b) opposite the first angular direction rotationally disengages the upper capstan from the input shaft and drives the lower capstan in the second angular direction to wrap the second drive cable about the lower capstan,
wherein the compliant member comprises a torsion spring, wherein the torsion spring is coiled around an axis which is parallel to an axis of rotation of the input shaft, and wherein the torsion spring is contained within at least one of the first capstan assembly and the lower capstan assembly.