Patent Description:
Slack or low tension in cables of a surgical instrument may in some situations cause jumpy or unpredictable motion of an end effector of the surgical instrument. One way to ensure that sufficient cable tension exists throughout a surgical instrument's design life is to preload the cable with sufficiently high tension to withstand some preloaded cable tension degradation, particularly when the end effector may be used for pushing and pulling, clamping, gripping, or other actions that encounter resistance. However, the tension preload in the cables can increase the forces that a drive system must apply to operate the surgical instrument. The preload can increase friction where the cables ride along surfaces of the surgical instrument. The preload can also cause friction where the cables contact curved surfaces of an opening through which the cables pass.

<CIT> discloses an endoscopic system that includes an insertion-section, a wire, an adjustment-unit, a memory, a shape-acquiring-unit and a controller. The insertion-section includes a tubular-section and a bending-section. The wire is inserted in the insertion-section and pulled and loosened to bend the bending-section. The adjustment-unit adjusts tensile force applied to the wire. The memory stores correspondent information including a relationship between increase/decrease information indicative of increase/decrease in the tensile force due to a shape of the tubular-section and shape information indicative of the shape of the tubular-section. The shape-acquiring-unit acquires the shape of the tubular-section. The controller obtains the increase/decrease information corresponding to the shape information acquired by the shape-acquiring-unit with reference to the correspondent information, generates an adjustment signal configured to drive the adjustment-unit based on the increase/decrease information, and outputs the adjustment signal to the adjustment-unit.

<CIT> discloses another prior art system for tensioning drive cables.

In one aspect, a computer-assisted surgical system includes a surgical instrument. The surgical instrument includes a chassis at a proximal end of the surgical instrument, a distal end component at a distal end of the surgical instrument, a plurality of first drive components mounted in the chassis, a second drive component mounted in the chassis, a plurality of flexible tensioning element each coupled between a corresponding one of the plurality of first drive components and the distal end component, and a dynamic preload tensioner mounted in the chassis and coupled to be driven by the second drive component. Each of the flexible tensioning elements extends along a corresponding path. The dynamic preload tensioner is configured to be driven by the second drive component to move relative to the chassis and as a result change the corresponding path of and apply a preload tension in each of the flexible tensioning elements as the dynamic preload tensioner moves relative to the chassis.

In another aspect, a method includes moving the dynamic preload tensioner of the surgical instrument to increase tension to a predefined preload tension in each of the plurality of flexible tensioning elements of the surgical instrument. The method further includes, in response to detecting the predefined tension in each of the plurality of flexible tensioning elements, maintaining a position of the dynamic preload tensioner relative to the chassis.

In some implementations, the system includes a manipulator on which the surgical instrument is mounted. The manipulator includes, for example, a first drive output positioned to drive the first drive components of the surgical instrument and a second drive output positioned to drive the second drive component of the surgical instrument.

In some implementations, the system further includes a memory and a computer processor configured to execute instructions stored in the memory to perform operations.

The operations include, for example, driving the second drive component to move the dynamic preload tensioner from a first position to a second position relative to the chassis. In some cases, the second drive component is driven when the processor receives information indicating the instrument is mounted to the manipulator. In some cases, the operations further include driving the second drive component until the processor receives information indicating that a predefined tension in each of the flexible tensioning elements is reached. In some cases, the information indicative of the predefined tension in the flexible tensioning element is based on a torque of an actuator driving the second drive output.

Other optional features are defined in the dependent claims.

Advantages of the foregoing may include, but are not limited to, those described below.

Other potential features, aspects, and advantages will become apparent from the description, the drawings, and the claims.

A flexible tensioning element (e.g., a cable, a cable-hypotube combination, or the like) of a surgical instrument includes a preload tension that enables an input tension load to be transferred through the flexible tensioning element from a first end to a second end. The preload tension can also inhibit the flexible tensioning element from becoming slack when another flexible tensioning element is loaded such that the flexible tensioning element relaxes. The preload tension corresponds to, for example, a tension existing in the flexible tensioning element absent an input tension load to drive a distal end component coupled to the flexible tension element, a tension existing in the flexible tensioning element before the input tension load is applied to drive the distal end component, a tension existing in the flexible tensioning element to reduce slack in the flexible tensioning element, etc. The preload tension, as described herein, can be adjusted, e.g., after the manufacturing of the surgical instrument is complete, to improve operability and adaptability of the surgical instrument.

As described herein, an instrument tensioning element initially experiences a first preload tension, which may be zero or another value sufficient to maintain the instrument's mechanical integrity during shipment, storage, etc. Either before or during operation of the instrument, a controller increases the instrument tensioning element's first preload tension to a second preload tension larger than the first preload tension. During operation, the tensioning element will experience two forms of tension-the second preload tension and the actuation tension load used to drive an instrument distal end component to which the tensioning element is coupled. After operation, the instrument tensioning element's second preload tension is optionally reduced to a value less than the second preload tension, such as the first preload tension. The reduction in preload tension may be controlled by the controller, or it may otherwise be manually or mechanically controlled when an instrument is removed from its instrument carriage after operation. The cycle of dynamically increasing and decreasing the instrument tensioning element's preload tension may optionally be repeated during one or more subsequent instrument operations or uses. Thus the instrument tensioning element experiences a dynamic change in preload tension that is controlled at least in part by a controller, in addition to the actuation tension load changes that are applied to move or allow movement of the distal end component.

<FIG> depicts an example of a surgical system <NUM> including a surgical instrument <NUM> that includes a chassis <NUM>, drive components 104a, 104b, a flexible tensioning element <NUM>, and a distal end component <NUM>. The drive component 104b is, for example, a dynamic preload tensioner drive component that is driven to manipulate a dynamic preload tensioner <NUM>. The drive component 104a is, for example, a flexible tensioning element drive component that is driven to drive the flexible tensioning element <NUM>. The chassis <NUM> is at a proximal portion <NUM> of the surgical instrument <NUM>, and the distal end component <NUM> is at a distal portion <NUM> of the surgical instrument <NUM>. The drive components 104a, 104b are mounted in the chassis <NUM>, i.e., near or at the proximal portion <NUM> of the surgical instrument <NUM>. The drive components 104a, 104b include, for example, mechanical components that carry mechanical load from a drive system <NUM>. The drive components 104a, 104b are, for instance, driven components that move when driven by the drive system <NUM>. The flexible tensioning element <NUM> is coupled between the drive component 104a and the distal end component <NUM>. The flexible tensioning element <NUM> extends along a path, for example, between the drive component 104a and the distal end component <NUM>. The drive component 104a transfers an actuation load applied to the drive component 104a to the flexible tensioning element <NUM>.

The surgical instrument <NUM> further includes a dynamic preload tensioner <NUM>. The dynamic preload tensioner <NUM> is, in some cases, mounted in the chassis <NUM>. In some implementations, the dynamic preload tensioner <NUM> is at least partially mounted in the chassis <NUM> and/or entirely contained within the chassis <NUM>. The dynamic preload tensioner <NUM> is coupled to the drive component 104b. The drive component 104a, in some cases, is coupled to a drive mechanism to transfer load applied to the drive component 104b to the flexible tensioning element <NUM>. The dynamic preload tensioner <NUM> is configured to be driven by the drive component 104b to be moved relative to the chassis <NUM>. In this regard, the dynamic preload tensioner <NUM> is controllably positioned to change the path of the flexible tensioning element <NUM> as the dynamic preload tensioner <NUM> moves relative to the chassis <NUM>.

In some implementations, in cases in which the drive component 104a is driven, the drive component 104a applies an axial (e.g., lengthwise) actuation load to the flexible tensioning element <NUM>. An axis of the axial load is, for example, parallel to an axis of a tension force in the flexible tensioning element <NUM>. In cases in which the drive component 104b is driven, the drive component 104b operates the dynamic preload tensioner <NUM> to apply a transverse (e.g., crosswise) load to the flexible tensioning element <NUM>. The transverse load, for instance, bends the flexible tensioning element <NUM> in a manner that induces a tension in the flexible tensioning element <NUM>. In this regard, when the drive component 104b has not been driven to operate the dynamic preload tensioner <NUM>, a first tension exists within the flexible tensioning element <NUM>. The drive component 104b, when driven, causes a second tension to exist in the flexible tensioning element. The first tension corresponds to the preload tension in the flexible tensioning element <NUM> absent operation of the dynamic preload tensioner <NUM>, and the second tension corresponds to a preload tension in the flexible tensioning element <NUM> after the drive component 104b has been operated. Due to the operation of the dynamic preload tensioner <NUM>, the second tension is greater than the first tension.

While a single flexible tensioning element <NUM> is described and shown in <FIG>, examples described herein are applicable to surgical instruments with a dynamic preload tensioner that simultaneously changes both the path of one flexible tensioning element and the path of another flexible tensioning element. Two flexible tensioning elements are, for example, coupled to the same drive component, e.g., the drive component 104a, or the flexible tensioning elements are coupled to independently operable drive components.

<FIG> depict various examples of configurations of drive components to drive flexible tensioning elements 1202a, 1202b. When the flexible tensioning element 1202a is driven, a distal end component to which the flexible tensioning element 1202a is connected moves in a degree of freedom in a first direction. When the flexible tensioning element 1202b is driven, the distal end component to which the flexible tensioning element 1202b is also connected moves in the degree of freedom in a second direction. In this regard, the flexible tensioning elements 1202a, 1202b are driven in a manner to precisely control, for example, bi-directional movement of the distal end component in the degree of freedom.

<FIG> depict mechanisms in which the flexible tensioning elements 1202a, 1202b are driven by separate drive components. In some implementations, as shown in <FIG>, the drive system <NUM> applies forces to drive components 1204a, 1204b. The first and second drive components are configured to translate when forces are applied to them, e.g., translate in a manner to apply tension to the flexible tensioning elements 1202a, 1202b. The drive system <NUM>, for instance, translates a first drive input to apply a force 1206a to the flexible tensioning element 1202a, and translates a second drive input to apply a force 1206b to the flexible tensioning element 1202b. By applying the force 1206a, the drive system <NUM> drives the drive component 1204a to move proximally to apply a tension to the flexible tensioning element 1202a. By applying the force 1206b, the drive system <NUM> drives the drive component 1204b to move proximally to apply a tension to the flexible tensioning element 1202b. The drive system <NUM> applies the forces 1206a, 1206b in a manner to control movement of the distal end component, e.g., applies the force 1206a to move the distal end component in the first direction in the degree of freedom, and applies the force 1206b to move the distal end component in the second direction in the degree of freedom.

Rather than translating due to forces applied by the drive system <NUM>, in some cases, as shown in <FIG>, drive components 1208a, 1208b rotate about rotational centers 1210a, 1210b, respectively, in response to the forces applied by the drive system <NUM>. The drive components 1208a, 1208b are, for example, levers rotatable about the rotational centers 1210a, 1210b respectively. The flexible tensioning elements 1202a, 1202b are attached to the drive components 1208a, 1208b, respectively, such that distally directed forces 1211a, 1211b applied to the levers result in proximally directed forces, e.g., tensions, to be applied to the flexible tensioning elements 1202a, 1202b, respectively. The drive component 1208a applies a tension 1212a to the flexible tensioning element 1202a when the drive component 1208a is rotated, e.g., rotated counterclockwise about the rotational center 1210a as shown in <FIG>. The drive component 1208a rotates, and hence applies the tension 1212a, in response to the force 1211a applied by the drive system <NUM>. The drive component 1208b applies a tension 1212b to the flexible tensioning element 1202b when the drive component 1208b is rotated, e.g., rotated clockwise about the rotational center 1210b as shown in <FIG>. The drive component 1208b rotates, and hence applies the tension 1212b, in response to the force 1211b applied by the drive system <NUM>.

Rather than applying a force to rotate the drive components, in some cases, as shown in <FIG>, the drive system <NUM> applies torques 1216a, 1216b to rotate drive components 1218a, 1218b, respectively. The drive components 1218a, 1218b are, for example, rotatable capstans to which the flexible tensioning elements 1202a, 1202b are attached. The capstans, when rotated due to the torques 1216a, 1216b, apply tensions 1219a, 1219b to the flexible tensioning elements 1202a, 1202b, respectively. The drive component 1218a rotates in response to the drive system <NUM> applying the torque 1216a, and the drive component 1218b rotates in response to the drive system <NUM> applying the torque 1216b. When the drive components 1218a, 1218b rotate, the flexible tensioning elements 1202a, 1202b are wrapped around the drive components 1218a, 1218b such that the tensions 1219a, 1219b are applied to the flexible tensioning elements 1202a, 1202b.

In some cases in which the flexible tensioning elements 1202a, 1202b are attached to separate drive components, for example, as described with respect to <FIG>, to move the distal end component in a first direction, one of the drive components is driven to apply the tension to one of the flexible tensioning elements while the other of the drive components is operated in a manner to maintain minimal tension in the other of the flexible tensioning elements. The minimal tension is applied to the other of the flexible tensioning elements to avoid slack. The tension is applied to the flexible tensioning element to move the distal end component in a first direction. Furthermore, the other of the flexible tensioning element is relaxed to avoid impeding movement of the distal end component in the first direction. On the other hand, to move the distal end component in a second direction, the other of the flexible tensioning elements is driven. The flexible tensioning element is relaxed to avoid impeding movement of the distal end component in the second direction.

In some implementations, rather than being attached to separate drive components, the flexible tensioning elements are attached to the same drive component. Such examples are illustrated in <FIG>. In some cases, as shown in <FIG>, the drive system <NUM> applies forces 1220a, 1220b to a single drive component <NUM> to apply tensions to the flexible tensioning elements 1202a, 1202b attached to the drive component <NUM>. The drive component <NUM> rotates about a rotational center <NUM> when the drive component is driven by the forces 1220a, 1220b, rotating in a first direction in response to the force 1220a and rotating in a second direction in response to the force 1220b. The force 1220a drives the flexible tensioning element 1202b and relaxes the flexible tensioning element 1202a, and the force 1220b drives the flexible tensioning element 1202a and relaxes the flexible tensioning element 1202a. The drive component is, for example, a lever to which the flexible tensioning elements 1202a, 1202b are attached, the flexible tensioning elements 1202a, 1202b attached to opposing lever arms of the lever, e.g., lever arms extending away from the rotational center <NUM> in opposite directions.

Rather than applying forces to move the drive component, in some cases, as shown in <FIG>, the drive system <NUM> applies a torque <NUM> to a single drive component <NUM> to drive the flexible tensioning element 1202b. The torque <NUM> causes the flexible tensioning element 1202a to relax. The drive system <NUM> applies a torque in an opposite direction of the torque <NUM> to the drive component <NUM> to drive the flexible tensioning element 1202a. Such a torque causes the flexible tensioning element 1202b to relax. The single drive component <NUM> is, for example, a rotatable capstan.

Referring back to <FIG>, if the drive component 104a is coupled to multiple flexible tensioning elements, when the drive component 104a is driven in a first direction, the drive component 104a applies an actuation tension load to one of the flexible tensioning elements to move the distal end effector in a first direction. The other of the flexible tensioning elements, in some cases, relaxes. When the drive component 104a is driven in a second direction, the drive component 104a applies an actuation tension load to the other of the flexible tensioning elements to move the distal end effector in a second direction. The two flexible tensioning elements are, for example, wrapped in opposite directions around the drive component 104a. In some implementations, the flexible tensioning elements, when driven, apply a load to move the distal end component at a joint so as to move the distal end component in a clamping motion, a pitch motion, a yaw motion, a roll motion, etc..

When one of the flexible tensioning elements is driven and the other is relaxed, to prevent the relaxed flexible tensioning element from experiencing unacceptably low tension or slack, the flexible tensioning elements can be preloaded with a tension so that an acceptable minimum tension always exists on a tensioning element during instrument operation. For example, the acceptable minimum tension is equal to or greater than minimum tension used in the flexible tensioning elements during steering of the distal end component. As a result, when an actuation tension in one flexible tensioning element is applied, the other flexible tensioning element relaxes but does not become slack due to the applied actuation tension on the opposite tensioning element.

The surgical system <NUM> includes, in some examples, a controller <NUM>. The controller <NUM> is configured to execute instructions stored on the memory <NUM> to perform operations, e.g., to control the drive system <NUM>. The controller <NUM> operates the dynamic preload tensioner <NUM> such that the dynamic preload tensioner <NUM> moves, e.g., relative to the chassis <NUM>, to adjust the path of the flexible tensioning element <NUM>. The path adjustment, i.e., the increase in the path length, adjusts a tension in the flexible tensioning element <NUM>. In some cases, the controller <NUM> operates an actuator of the drive system <NUM> to move the dynamic preload tensioner <NUM>. The drive system <NUM> applies a load to the drive component 104b, which in turn applies a load to the dynamic preload tensioner <NUM>. The dynamic preload tensioner <NUM>, under the load applied by the drive component 104b, moves relative to the chassis <NUM>.

The flexible tensioning element <NUM> is, for instance, a cable, a cable and hypotube combination, a wire, a filament, a bundle of filaments, braided filaments, a thread, a rope, twisted filaments, or other element in which a tension can exist. The flexible tensioning element <NUM>, in some cases, is susceptible to creep, stress relaxation, or other changes in material properties of the flexible tensioning element <NUM>. The flexible tensioning element <NUM> is formed from, for instance, a metal or a polymer. In cases in which the flexible tensioning element <NUM> is formed from a polymer, the flexible tensioning element <NUM> is, for instance, a polyethylene, a liquid crystal polymer, a polyester, etc..

In some implementations, the distal end component <NUM> is at a distal portion of a tubular member <NUM> attached to the chassis <NUM>. The tubular member <NUM> is, for example, a shaft of a minimally invasive surgical instrument. The tubular member <NUM> is, for instance, an elongate body through which the flexible tensioning element <NUM> extends. The tubular member <NUM> extends distally from the chassis <NUM>. A distal end of the tubular member <NUM> is coupled to the distal end component <NUM>. The tubular member <NUM> contains at least a portion of the path of the flexible tensioning element <NUM>. The tubular member <NUM>, for instance, contains the flexible tensioning element <NUM> as the flexible tensioning element <NUM> extends from the chassis <NUM> to the distal end component <NUM>. The tubular member <NUM>, in some cases, supports the distal end component <NUM> to fix the position of the distal end component <NUM> relative to the chassis <NUM> as a load is applied to the flexible tensioning element <NUM> to steer the distal end component <NUM>.

In some implementations, the dynamic preload tensioner <NUM> is movable between a first position <NUM> (shown in <FIG> as solid lines) and a second position <NUM> (shown in <FIG> as dashed lines). The dynamic preload tensioner <NUM> is, for example, movable to any position in a range of positions between the first position <NUM> and the second position <NUM>. In some cases, the first position <NUM> corresponds to an initial position of the dynamic preload tensioner <NUM>, e.g., the position of the dynamic preload tensioner <NUM> after the manufacturing of the surgical instrument <NUM> is complete, the position of the dynamic preload tensioner <NUM> absent operation of the dynamic preload tensioner <NUM>. At the first position <NUM> of the dynamic preload tensioner <NUM>, a first preload tension exists in the flexible tensioning element <NUM>. At the second position <NUM> of the dynamic preload tensioner <NUM>, a second preload tension exists in the flexible tensioning element <NUM>. The second preload tension is larger than the first preload tension. In some cases, the first tension is zero. And in some cases, the first tension corresponds to an initial preload tension set during manufacture of the surgical instrument <NUM>. The first tension is, for instance, a portion of the preload tension that exists in the flexible tensioning element <NUM> after the dynamic preload tensioner <NUM> is operated to cause the second tension.

In some implementations, the dynamic preload tensioner <NUM> is positioned to apply an adjustable preload tension to the flexible tensioning element <NUM> when the dynamic preload tensioner <NUM> moves to adjust the path of the flexible tensioning element <NUM>. If an initial preload tension exists in the flexible tensioning element <NUM>, the adjustable preload tension applied to the flexible tensioning element <NUM> results in an overall preload tension in the flexible tensioning element <NUM>, corresponding to, for example, the sum of the adjustable preload tension and the portion of the initial preload tension in the flexible tensioning element <NUM>.

Referring to <FIG>, in some implementations, the surgical instrument <NUM> is mounted to a manipulator <NUM>. The manipulator <NUM> is, for example, a remotely controllable manipulator that can be operated by a surgeon at a location remote from the manipulator <NUM>. The surgeon, for instance, operates control inputs on a console in communication with the manipulator <NUM>, and the console generates control signals for a drive system of the manipulator <NUM> to control motion of the joints (e.g., joint <NUM>) of the manipulator <NUM>. The control signals, for instance, selectively activate actuators of the drive system of the manipulator <NUM>. Such a surgical system architecture is known and can be seen, for example, in the da Vinci® Surgical Systems commercialized by Intuitive Surgical, Inc. , Sunnyvale, California, and in various patents, such as U. Patents No. <CIT>), <CIT>), and <CIT>), all of which are incorporated herein by reference.

The manipulator <NUM> includes, for example, an instrument carriage <NUM> to which the surgical instrument <NUM> can be mounted. The instrument carriage <NUM>, for example, releasably supports the surgical instrument <NUM>. The instrument carriage <NUM> includes one or more actuators that are part of the drive system of the manipulator <NUM>. The instrument carriage <NUM> is, for instance, a mechanical interface connecting the drive system of the manipulator <NUM> to driven components of the surgical instrument. In some cases, when the surgical instrument <NUM> is mounted to the instrument carriage <NUM>, the drive system of the manipulator <NUM> engages with drive components 104a, 104b of the surgical instrument <NUM> such that activation of the drive system drives the drive components 104a, 104b. The drive system of manipulator <NUM>, for instance, includes multiple independently controllable drive outputs that connect to the drive components 104a, 104b of the surgical instrument <NUM>. In some examples, when the surgical instrument <NUM> is mounted to the instrument carriage204, one drive output is positioned to drive the drive component 104a, and another one of the drive outputs is positioned to drive the drive component 104b.

The drive system of the manipulator <NUM>, in some examples, corresponds to the drive system <NUM> described with respect to <FIG>. As a result, the drive system of the manipulator <NUM> is operable with the drive components 104a, 104b, to apply a load to the flexible tensioning element <NUM> and/or to cause the dynamic preload tensioner <NUM> to move. A drive output, for example, of the drive system of the manipulator <NUM> is operably connected to the dynamic preload tensioner <NUM> such that the dynamic preload tensioner <NUM> moves relative to the chassis <NUM> when the drive output is activated.

<FIG> depicts another example of a surgical instrument <NUM> that can be mounted to the manipulator <NUM>. The surgical instrument <NUM> includes a driven interface assembly <NUM>, e.g., a mechanical interface to mechanically couple drive components <NUM> of the surgical instrument <NUM> with the drive system of the manipulator <NUM>. The drive components <NUM> of the surgical instrument <NUM> include, for example, driven disks of the surgical instrument <NUM> that are rotatable by the drive system of the manipulator <NUM>.

The surgical instrument <NUM> also includes a transmission unit <NUM>, a tubular member <NUM> (e.g., the instrument shaft), a joint <NUM>, and a distal end component <NUM>. The transmission unit <NUM> transfers the loads applied by the drive system of the manipulator <NUM> to move the distal end component <NUM>. The distal end component <NUM> is, for instance, an end effector that is operated during a surgical operation. The joint <NUM> is, for instance, a wrist joint that is movable to control an orientation of the distal end component <NUM>.

In some implementations, the surgical instrument <NUM> includes flexible tensioning elements coupled to the drive components <NUM> mounted in a chassis <NUM> of the surgical instrument <NUM>. As described with the flexible tensioning element <NUM> of <FIG>, the flexible tensioning elements each extend along a path between a drive component and the distal end component. In some cases, multiple flexible tensioning elements extend from a single drive component to the distal end component <NUM> to control motion of the distal end component <NUM> along a degree of freedom.

The surgical instrument <NUM> includes one or more dynamic tensioners. In some implementations, the surgical instrument includes a single dynamic tensioner. One of the drive components <NUM> is coupled to the dynamic tensioner, and another one of the drive components is coupled to the flexible tensioning element, e.g., a proximal end of the flexible tensioning element. In implementations in which the surgical instrument includes multiple flexible tensioning elements, the single dynamic tensioner is movable relative to the chassis <NUM> to change a path of one, some, or all of the flexible tensioning elements.

In other implementations, the surgical instrument includes multiple dynamic tensioners. In these implementations, the surgical instrument includes, for example, a dynamic tensioner for each flexible tensioning element of the surgical instrument <NUM>. Alternatively or additionally, the surgical instrument includes a dynamic tensioner associated with each drive component. Each dynamic tensioner, when its associated drive component is driven, adjusts the path of its associated flexible tensioning element. For example, one individual dynamic tensioner is positioned to controllably change the tension in a first flexible tensioning element, and a second individual dynamic tensioner is positioned to controllably change the tension in a second flexible tensioning element.

As shown in <FIG>, in some implementations, a first dynamic tensioner 1302a is positioned to engage a flexible tensioning element 1304a, and a second dynamic tensioner 1302b is positioned to engage a flexible tensioning element 1304b. The flexible tensioning elements 1304a, 1304b are driven to move a distal end component <NUM> along a single degree of freedom, e.g., in a first direction if the flexible tensioning element 1304a is driven and in a second direction if the flexible tensioning element 1304b is driven. The first and second dynamic tensioners 1302a, 1302b are, for example, independently driven, e.g., operated by different drive components 1306a, 1306b and driven by different actuators of the drive system <NUM>. In this regard, the preload tension applied to the first flexible tensioning element 1304a can be set in a manner independent from the preload tension applied to the second flexible tensioning element 1304b. In contrast, in some implementations as shown in <FIG>, a single dynamic tensioner <NUM> is positioned to engage both of the flexible tensioning elements 1304a, 1304b. The dynamic tensioner <NUM> is operated by a single drive component (not shown) and is driven by a single actuator of the drive system <NUM>. In this regard, the drive system <NUM> operates a single dynamic tensioner <NUM> to apply preload tensions to the flexible tensioning elements 1304a, 1304b.

The transmission unit <NUM> includes mechanical components, such as gears, levers, gimbals, cables, etc., to transfer loads from the drive components <NUM> of the surgical instrument <NUM> to the distal end component <NUM>. The mechanical components of the transmission unit <NUM>, for example, form a mechanism in the proximal portion of the surgical instrument <NUM> that mechanically couples the flexible tensioning elements of the surgical instrument <NUM> with the drive components <NUM> of the driven interface assembly <NUM>.

In some implementations, the mechanical components mechanically couple a proximal end of a flexible tensioning element with one of the drive components, e.g., the drive component 104a of <FIG>. Alternatively or additionally, the mechanical components mechanically couple a portion of the flexible tensioning element between distal and proximal ends of the flexible tensioning element and one of the drive components, e.g., the drive component 104b of <FIG>. In such a case, the drive component, when driven, moves the dynamic tensioner to adjust the path of the flexible tensioning element, for example, by applying a transverse load on the flexible tensioning element.

If the drive components <NUM> include driven capstans, rotation of a driven capstan applies a tension load on a flexible tensioning element, e.g., pulls the flexible tensioning element. The flexible tensioning element then applies a load on a mechanical link in the distal end component <NUM> to move the distal end component <NUM>, e.g., to reposition or to reorient a link of the distal end component <NUM>.

The tubular member <NUM> is, in some cases, rigid. In some implementations, the tubular member <NUM> is bendable relative to the transmission unit <NUM>. The tubular member <NUM> is, for example, elastically bendable such that the tubular member <NUM> returns to its original shape upon removal of a force that bends the tubular member <NUM>. In other instances, however, tubular member is flexible but does not return to its initial shape after being flexed until the controller generates commands to the manipulator to return the tubular member to the initial shape.

<FIG> depicts a flow chart of a process <NUM>, e.g., performed by the controller <NUM>, to operate a dynamic tensioner. The controller <NUM>, for instance, performs the process <NUM> in connection with the surgical system <NUM> described with respect to <FIG>.

At operation <NUM>, the controller <NUM> moves a dynamic tensioner, e.g., the dynamic preload tensioner <NUM>, of a surgical instrument, e.g., the surgical instrument <NUM>, to increase tension in a flexible tensioning element, e.g., the flexible tensioning element <NUM>, of the surgical instrument.

At operation <NUM>, the controller <NUM> drives the flexible tensioning element to move a distal end component, e.g., the distal end component <NUM>, while a position of the dynamic tensioner is maintained.

In some implementations, before moving the dynamic tensioner to increase the tension, the controller <NUM> receives information indicating that the surgical instrument has been mounted. The information, for instance, indicates that the surgical instrument has been mounted to a manipulator. In some examples, the controller <NUM> moves the dynamic tensioner when the controller <NUM> receives the information indicating that the surgical instrument has been mounted. In some implementations, the controller <NUM> receives information indicative of the predefined tension, e.g., a target value for a tension force in the flexible tensioning element. In some cases, the controller <NUM> determines when the tension in the flexible tensioning element has reached a predefined tension. The controller <NUM> maintains the position of the dynamic tensioner in response to determining that the tension in the flexible tensioning element has reached the predefined tension.

In some implementations, the controller <NUM> moves the dynamic tensioner of the surgical instrument by commanding drive system <NUM> to drive a corresponding drive component, e.g., the drive component 104b, to move the dynamic tensioner from a first position to a second position. In response to determining that the tension in the flexible tensioning element <NUM> has reached a predefined tension, the controller <NUM> maintains the position of the dynamic preload tensioner <NUM> such that the tension in the flexible tensioning element <NUM> is maintained at or above the predefined tension. If the controller <NUM> drives the drive component to move the dynamic tensioner, the controller <NUM> drives the drive component until the controller <NUM> receives the information indicating that the predefined tension is reached.

Alternatively or additionally, the controller <NUM> moves the dynamic tensioner of the surgical instrument while monitoring the tension in the flexible tensioning element. The controller <NUM>, for instance, determines the tension of the flexible tensioning element <NUM> by monitoring the tension of the flexible tensioning element <NUM> during movement of the dynamic preload tensioner <NUM>. In some implementations, to monitor the tension in the flexible tensioning element, the controller <NUM> receives information indicative of the tension in the flexible tensioning element. The information is, for instance, received from a sensor to measure in the flexible tensioning element. The sensor is, for example, a torque sensor associated with an actuator driving the drive component to drive the dynamic tensioner. The torque sensor generates a signal indicative of the torque applied by the actuator, and the controller <NUM>, in some cases, determines the tension in the flexible tensioning element based on the torque. In some cases, the sensor is a torque sensor associated with an actuator driving the drive component to drive the flexible tensioning element. In an example, when the controller <NUM> drives a first drive component to move the dynamic tensioner to increase the tension in the flexible tensioning element, the controller <NUM> determines when torque measured by a torque sensor associated with a second drive component configured to drive the flexible tensioning element. The controller maintains the position of the first drive component after determining that the torque measured by the torque sensor is indicative of the tension in the flexible tensioning element reaching the predefined tension. Various other sensors may be used to sense tension in the flexible tensioning element, such as various types of strain or torque sensors mounted on a corresponding drive component or other component in the drive train associated with the flexible tensioning element.

In some implementations, the controller <NUM> drives the flexible tensioning element by driving a drive component, e.g., the drive component 104a. In this regard, the controller <NUM>, in some cases, drives one drive component to move the dynamic tensioner and drives a second drive component to drive the flexible tensioning element to move the distal end component.

<FIG> depict a variety of examples of dynamic tensioners that change a path of a flexible tensioning element of a surgical instrument when operated. In each of these examples and other examples described herein, the path of the flexible tensioning element is changed by operation of a dynamic tensioner via a controller. In some cases, the dynamic tensioner applies a transverse load on the flexible tensioning element that adjusts the path of the flexible tensioning element. In some cases, the dynamic tensioner causes an axial load to be applied to the flexible tensioning element to adjust the path of the flexible tensioning element. This axial load is independent from the axial load applied to the flexible tensioning element to steer the distal end component. The path change of the flexible tensioning element results in the flexible tensioning element experiencing a tension, e.g., a preload tension. The dynamic tensioner is operable to generate an adjustable preload tension on the flexible tensioning element such that the preload tension can be applied or can be released. When the adjustable preload tension reaches a desired level, the preload tension can be locked to maintain the adjustable dynamic preload tension at the desired level while the flexible tensioning element is driven to steer the distal end component. Such tension locking may be done by keeping a dynamic preload tensioner in position once a desired preload tension value is established in a tensioning element, or by actively sensing tension in a tensioning element and continuing to dynamically adjust a dynamic tensioner to maintain the desired preload tension.

As described with respect to the example of <FIG>, the path of the flexible tensioning element is changed to apply the preload tension to the flexible tensioning element. In some implementations, the path is lengthened by extending a portion of the path longitudinally. In some implementations, the path is lengthened by adjusting an angle between a first portion of a path and a second portion of a path. In some implementations, the path is lengthened by adding a bend in the path, e.g., by bending the flexible tensioning element.

<FIG> depict an example of a dynamic tensioner <NUM> for a surgical instrument, the dynamic tensioner including a tensioning drum <NUM> positioned to engage a flexible tensioning element 504a. The tensioning drum <NUM> is axially movable such that it engages the flexible tensioning element 504a and changes the path of the flexible tensioning element 504a. In some examples, the tensioning drum <NUM> is axially movable relative to the chassis of the surgical instrument. The tensioning drum <NUM> is, for example, a cylindrical member movable along its central axis and positioned to engage the flexible tensioning element 504a as it moves along the central axis.

In some implementations, to change the path of the flexible tensioning element 504a, the tensioning drum <NUM> redirects a path of the flexible tensioning element 504a as the tensioning drum <NUM> moves to engage the flexible tensioning element 504a. The flexible tensioning element 504a extends along a first portion of its path from a drive component <NUM> to the tensioning drum <NUM>. The flexible tensioning element 504a then bears against the tensioning drum <NUM>, e.g., a top surface <NUM> of the tensioning drum <NUM>, such that the path of the flexible tensioning element 504a is redirected. In particular, the path is redirected toward a distal end component of the surgical instrument. In some cases, the tensioning drum <NUM> includes an aperture <NUM> through which the flexible tensioning element 504a is routed. The path of the flexible tensioning element 504a extends from the drive component <NUM> toward the aperture <NUM>, then through the aperture <NUM> while the flexible tensioning element 504a bears against the top surface <NUM> of the tensioning drum <NUM>. The path of the flexible tensioning element 504a then extends toward a joint of the distal end component.

As the tensioning drum <NUM> moves axially, the tensioning drum <NUM>, e.g., the top surface <NUM> of the tensioning drum <NUM>, engages the flexible tensioning element 504a and causes the flexible tensioning element 504a to move with the tensioning drum <NUM>. Because the flexible tensioning element 504a bears against the tensioning drum <NUM>, movement of the tensioning drum <NUM> causes the path of the flexible tensioning element 504a to change. In some implementations, the movement of the tensioning drum <NUM> causes the path change by repositioning a bending point of the path, e.g., a point at which the path of the flexible tensioning element 504a is redirected.

In some implementations, to move the tensioning drum <NUM>, the dynamic tensioner <NUM> includes a drive mechanism <NUM> that, when driven, causes the axial movement of the tensioning drum <NUM>. The drive mechanism <NUM>, includes the drive component <NUM> driven by, e.g., the drive system of the manipulator <NUM>. The drive component <NUM> transfers the load through a gear system. In some examples, as the drive component <NUM> is driven to rotate, a gear <NUM> coupled to the drive component <NUM> is driven to rotate a gear <NUM>, which in turn rotates a tensioning gear <NUM>. The tensioning gear <NUM>, when rotated, drives the tensioning drum <NUM> to move axially relative to the tensioning gear <NUM>. The gear <NUM>, the gear <NUM>, and the tensioning gear <NUM> are each rotatably mounted to the chassis of the surgical instrument.

Referring to <FIG>, the tensioning gear <NUM>, for instance, bears against a ramp <NUM> defined by the chassis, e.g., formed on a surface <NUM> of the chassis of the surgical instrument. The ramp <NUM> increases in height relative to the surface <NUM> in the clockwise direction, as depicted in <FIG>. A top surface of the ramp <NUM>, for instance, follows a helical path extending away from the surface <NUM> of the chassis. The tensioning gear <NUM> follows the helical path as the tensioning gear <NUM> is rotated along the ramp <NUM>. The tensioning drum <NUM> is coupled to the tensioning gear <NUM> such that the tensioning drum <NUM> moves axially when the tensioning gear <NUM> is rotated along the ramp <NUM> of the chassis of the surgical instrument.

In some implementations, the tensioning drum <NUM> is keyed to the chassis such that the tensioning drum <NUM> does not rotate as the tensioning gear <NUM> rotates. Referring to <FIG>, the tensioning drum <NUM> is keyed to a locking element <NUM> of the chassis that engages with a corresponding locking element on a bottom surface of the tensioning drum <NUM>. The locking element <NUM> is, for instance, a protrusion that extends through the tensioning gear <NUM> and engages with a corresponding bore on the bottom surface of the tensioning drum <NUM>. Alternatively, the locking element <NUM> is a bore that engages with a corresponding protrusion on the bottom surface of the tensioning drum <NUM>. Engagement between the locking element <NUM> and the corresponding locking element on the tensioning drum <NUM> inhibits relative rotation of the chassis and the tensioning drum <NUM> such that, as the tensioning gear <NUM> rotates, the tensioning drum <NUM> does not rotate. Instead, both the tensioning gear <NUM> and the tensioning drum <NUM> move axially as the tensioning gear <NUM> rotates.

The axial position of the tensioning drum <NUM> relative to the surface <NUM> of the chassis depends on a rotational position of the tensioning gear <NUM> relative to the surface <NUM> of the chassis. As the tensioning gear <NUM> is rotated in a first direction <NUM>, the length of the path of the flexible tensioning element 504a increases and the tension existing in the flexible tensioning element 504a increases. Because of the slope of the ramp <NUM> bearing against the tensioning gear <NUM>, the tensioning gear <NUM> and the tensioning drum <NUM> move axially away from the surface <NUM> of the chassis as the tensioning gear <NUM> rotates in the first direction. In contrast, the tensioning drum <NUM> and the tensioning gear <NUM> move axially toward the surface <NUM> of the chassis as the tensioning gear <NUM> rotates in the second direction <NUM>. In this regard, as the tensioning gear <NUM> is rotated in the second direction <NUM>, the tension existing in the flexible tensioning element 504a decreases.

While described in terms of a single flexible tensioning element 504a, in some implementations, as shown in <FIG>, the tensioning drum <NUM> is positioned to engage with multiple flexible tensioning elements 504a-504d. In this regard, axial movement of the tensioning drum <NUM> changes a path of each of the flexible tensioning elements 504a-504d. In some implementations, as shown in <FIG>, in addition to the drive component <NUM> driven to operate the dynamic tensioner <NUM>, a drive component <NUM> is driven to apply a load to the flexible tensioning element 504a, e.g., to steer the distal end component. As described herein, a drive system of a remotely controllable manipulator can drive the drive component <NUM>. In some cases, the drive component <NUM> is coupled to multiple flexible tensioning elements, e.g., the flexible tensioning elements 504a, 504b. As the drive component <NUM> is driven, the drive components <NUM> applies tension to one of the flexible tensioning elements 504a, 504b while releasing tension to the other of the flexible tensioning elements 504a, 504b. The loads applied to the flexible tensioning elements 504a, 504b, for example, control motion of the distal end component along a single degree of freedom. The drive component <NUM>, in some example, drives the flexible tensioning element 504b such that the flexible tensioning element 504a is relaxed when the flexible tensioning element 504b is driven, and such that the flexible tensioning element 504b is relaxed when the flexible tensioning element 504a is driven. The preload tension applied by the dynamic tensioner <NUM> to the flexible tensioning elements 504a, 504b is sufficiently large such that the flexible tensioning elements 504a, 504b do not become slack as they relax during operation of the drive component <NUM>.

The drive component <NUM> is, for instance, a capstan that is rotatable by an actuator of the drive system of the manipulator. In some implementations, a torque on the capstan is determined, e.g., by the controller <NUM>, based on a current applied to the actuator to cause the capstan to rotate. The controller <NUM> in turn determines the force applied by the tensioning drum <NUM> on the flexible tensioning element 504a.

In some examples of a dynamic tensioner, the dynamic tensioner includes a spring to apply a static preload tension to the flexible tensioning element. The static preload tension is, for instance, a non-adjustable preload tension applied to the flexible tensioning element that maintains relative positions of components of the surgical instrument, e.g., mechanical integrity. During a surgical operation, the dynamic tensioner is operated to set an adjustable preload tension for the flexible tensioning element that is in addition to the preload tension caused by the spring. In some implementations, the spring is configured such that a force from the flexible tensioning element on the dynamic tensioner, e.g., due to a load applied to the flexible tensioning element to steer the distal end component, is not absorbed by the spring. When an actuation tension load is applied to the flexible tensioning element to steer the distal end component, the actuation load on the flexible tensioning element, rather than being absorbed by the spring, is transferred to the distal end component, e.g., is transferred to move the distal end component. In some cases, the dynamic tensioner, when operated, compresses the spring to cause the coils of the spring to contact one another such that, when the adjustable preload tension is applied using the dynamic tensioner, the spring cannot further absorb a force applied by the flexible tensioning element during steering of the distal end component. Likewise, in some cases, the dynamic tensioner, when operated causes the spring to disengage from a portion of the dynamic tensioner, e.g., the portion bearing against the flexible tensioning element, such that a force of the flexible tensioning element on the portion of the dynamic tensioner is not absorbed through compression of the spring.

Referring to <FIG>, in the example of the dynamic tensioner <NUM> including the tensioning drum <NUM>, in some examples, the dynamic tensioner <NUM> includes a spring <NUM> that applies a static preload tension. <FIG> shows the spring <NUM> in an expanded position in which the spring <NUM> applies the static preload tension to the flexible tensioning element. The spring <NUM>, for instance, is positioned between the tensioning drum <NUM> and the tensioning gear <NUM>. When the tensioning gear <NUM> is rotated, the tensioning gear <NUM> advances toward the tensioning drum <NUM> to compress the spring <NUM>. Referring to <FIG> showing the spring <NUM> in a compressed position, in the process of moving the tensioning drum <NUM>, the tensioning gear <NUM> compresses the spring <NUM> beyond a linear elastic range, e.g., such that the coils of the spring <NUM> contact one another. When the spring <NUM> is compressed in this manner, the static preload tension in the flexible tensioning element 504a caused by the spring <NUM> does not increase as the tensioning drum <NUM> is moved axially to increase the adjustable preload tension. The tensioning drum <NUM> is moved to change the path of the flexible tensioning element 504a while the coils of the spring <NUM> contact one another.

Referring to the example of a dynamic tensioner <NUM> shown in <FIG>, in some implementations, the dynamic tensioner <NUM> includes a lead screw <NUM> rotatable to adjust a path of the flexible tensioning element. The dynamic tensioner <NUM> includes an arm <NUM> with a first end <NUM> engaged to the lead screw <NUM>. The first end <NUM> of the arm <NUM> is, for example, movable along a longitudinal axis of the lead screw <NUM>. A nut <NUM> axially movable along the lead screw <NUM> couples the lead screw <NUM> to the first end <NUM> of the arm <NUM>. A second end <NUM> of the arm <NUM> includes a guide <NUM> including an aperture <NUM> through which the flexible tensioning element extends. The arm <NUM> is pivotally mounted to the chassis <NUM> of the surgical instrument at a pin <NUM>.

The lead screw <NUM>, for instance, is coupled to a drive component to be driven by the drive system of the manipulator to which the surgical instrument is mounted. An input load, e.g., a torque, applied to the lead screw <NUM> rotates the arm <NUM> relative to the chassis, e.g., such that the arm <NUM> pivots about the pin <NUM> on the chassis. When driven, the lead screw <NUM> rotates. In some implementations, the nut <NUM> moves axially when the lead screw <NUM> rotates, thereby rotating the first end <NUM> of the arm <NUM> about the pin <NUM>. The pivoting motion of the arm <NUM> then moves the second end <NUM> of the arm <NUM>. In particular, the second end <NUM> rotates such that a path of the flexible tensioning element (not shown) routed through the guide <NUM> is adjusted. The guide <NUM>, for example, bears against the flexible tensioning element such that movement of the guide <NUM> causes the path of the flexible tensioning element to be adjusted. The lead screw <NUM> is rotated to adjust the path of the flexible tensioning element, and hence to increase the tension in the flexible tensioning element. In some cases, the arm <NUM> applies a tension to the flexible tensioning element that increases nonlinearly with the torque applied to the lead screw <NUM>.

The flexible tensioning element is, for example, attached to a drive component 603a. In some cases, multiple flexible tensioning elements are attached to the drive component 603a and routed through apertures <NUM> on the guide <NUM>. The arm <NUM>, when pivoted, causes the guide <NUM> to pivot and move proximally away from the distal component, thereby adjusting the path of each of the flexible tensioning elements. The lead screw <NUM>, when rotated, applies preload tension to each of the flexible tensioning elements through manipulation of the guide <NUM>. In some implementations, another set of flexible tensioning elements are attached to a drive component 603b. The guide <NUM>, when pivoted, adjusts a path of each of the flexible tensioning elements. In some cases, the first set of flexible tensioning elements attached to the drive component 603a controls movement of the distal end component in one degree of freedom, and the second set of flexible tensioning elements attached to the drive component 603b controls movement of the distal end component in another degree of freedom.

In some examples of dynamic tensioners, the dynamic tensioner is driven by a drive component that, when operated, causes motion of the distal end component along a degree of freedom. The drive component is, for instance, a multi-functional drive component that is drivable to apply the adjustable preload tension and is also drivable to apply a load to steer the distal end component. In such cases, the manipulator to which the surgical instrument is mounted does not require a drive input to drive the dynamic tensioner independent from a drive input to steer the distal end component on the surgical instrument.

<FIG> depicts an assembly that mounts the tubular member <NUM> of the surgical instrument to the chassis of the surgical instrument, e.g., mounts the tubular member <NUM> to the chassis <NUM>. The assembly includes an assembly housing <NUM> that houses an example of a dynamic preload tensioner <NUM>. The assembly housing <NUM> is, in some cases, part of the chassis of the surgical instrument. The dynamic tensioner <NUM> is associated with a mechanism to control motion along a roll degree of freedom of the distal end component, e.g., rotation of the distal end component about a longitudinal axis <NUM> of the tubular member <NUM>. In some examples, a roll drive mechanism of the surgical instrument includes a gear <NUM> that, when driven, rotates the tubular member <NUM> coupled to the distal end component. The distal end component rotates, e.g., rolls about the longitudinal axis <NUM> of the tubular member <NUM>, in response to rotation of the tubular member <NUM>. The gear <NUM> is driven by a drive component that is, for example, coupled to a drive system of a manipulator.

Referring also to <FIG>, the dynamic tensioner <NUM> includes a rotatable member <NUM>. When the gear <NUM> is rotated to a predefined orientation, the gear <NUM> engages the rotatable member <NUM> such that the rotatable member <NUM> rotates relative to the assembly housing <NUM>, e.g., rotates about the longitudinal axis <NUM> of the tubular member <NUM>. The rotatable member <NUM> moves along the longitudinal axis <NUM> as the rotatable member <NUM> rotates relative to the assembly housing <NUM>. The gear <NUM> and the tubular member <NUM> move axially when the rotatable member <NUM> rotates. The distal end component moves axially when the tubular member <NUM> moves axially.

The tubular member <NUM>, as described herein, supports the distal end component and contains a portion of a path of a flexible tensioning element <NUM> coupled to the distal end component. In this regard, the path of the flexible tensioning element <NUM> is changed, e.g., a length of the path increases, when the tubular member <NUM> moves axially distally. In particular, the distal end component, in response to the axial movement of the tubular member <NUM>, moves away from the assembly housing <NUM>, thereby lengthening the path of the flexible tensioning element <NUM>. In particular, the length of the portion of the path of the flexible tensioning element <NUM> between the assembly housing <NUM> and the distal end component extends due to the axial movement of the tubular member <NUM>. The rotatable member <NUM>, when rotated, thus causes a tension to be applied to the flexible tensioning element <NUM>.

In some implementations, as the rotatable member <NUM> rotates, it follows a ramp <NUM>, e.g., a helical path, such that the rotatable member <NUM> moves along the longitudinal axis <NUM>. In some examples, the ramp <NUM> is formed on a delimiter member <NUM> in the assembly housing <NUM>. The rotatable member <NUM> is rotatable relative to the delimiter member <NUM>. The delimiter member <NUM> includes a delimiting portion <NUM> that, upon engaging with the rotatable member <NUM>, inhibits further rotation of the rotatable member <NUM>. The rotatable member <NUM> rotates along the ramp <NUM> about the longitudinal axis <NUM> and then contacts the delimiting portion <NUM>, which inhibits further rotation of the rotatable member <NUM>. Because the rotatable member <NUM> is rotated by the gear <NUM> driven to roll the distal end component, the delimiting portion <NUM>, when engaged with the rotatable member <NUM>, inhibits rotation of the gear <NUM> and thus inhibits further roll motion of the distal end component, e.g., rotation of the distal end component about the longitudinal axis <NUM> of the tubular member <NUM>.

In some implementations, the rotatable member <NUM> is movable between a first axial position <NUM> and a second axial position <NUM>. The tubular member <NUM> moves axially when the rotatable member <NUM> is moved from the first axial position <NUM> (proximal) to the second axial position <NUM> (distal). The axial movement of the tubular member <NUM> to the second axial position <NUM> extends the path of the flexible tensioning element <NUM>. In some implementations, an initial preload tension is applied to the flexible tensioning element <NUM> when the rotatable member <NUM> is in the first axial position <NUM>, and an operating preload tension greater than the initial preload tension is applied to the flexible tensioning element <NUM> when the rotatable member <NUM> is in the second axial position <NUM>. The operating preload tension is, for example, a preload tension that facilitates one-to-one transfer of an actuating tension load from a proximal end of the flexible tensioning element <NUM> to a distal end of the flexible tensioning element <NUM>, e.g., to the distal end component.

In some cases, the rotatable member <NUM> is lockable to the delimiter member <NUM>. The rotatable member <NUM> is, for instance, lockable to the delimiter member <NUM> when the rotatable member <NUM> is moved to the second axial position <NUM>. The rotatable member <NUM> includes, for instance, a locking portion <NUM> that engages a corresponding locking portion <NUM> of the delimiter member <NUM>. When the locking portion <NUM> of the rotatable member <NUM> engages the corresponding locking portion <NUM> on the delimiter member <NUM>, the rotatable member <NUM> is locked to the delimiter member <NUM> such that further rotation of the rotatable member <NUM> is inhibited. While first and second positions are described, in other implementations, the rotatable member <NUM> is lockable to one of multiple discrete positions. In this regard, one of multiple discrete preload tensions is applied to the flexible tensioning element <NUM> depending on the selected discrete position of the rotatable member <NUM>.

In some implementations, the gear <NUM> is rotatable over a first predefined range to roll the distal end component. The gear <NUM> is also rotatable beyond the first predefined range into a second predefined range. When the gear <NUM> is rotated into the second predefined range, the gear <NUM> engages the rotatable member <NUM> to rotate the rotatable member <NUM> relative to the delimiter member <NUM>. In this regard, the gear <NUM> does not rotate the rotatable member <NUM> while the gear <NUM> is rotated within the first predefined range. The first predefined range is, for instance, <NUM> degrees, e.g., the gear <NUM> rotates up to <NUM> degrees in a clockwise direction and up to <NUM> degrees in a counterclockwise direction from its initial position. The second predefined range is, for example, <NUM> to <NUM> degrees beyond the first predefined range. The gear <NUM>, for instance, rotates <NUM> to <NUM> degrees past the first predefined range when the gear <NUM> is rotating in the second predefined range.

In some cases, the first predefined range is a controller-enforced range. In some cases, the controller, e.g., the controller <NUM>, inhibits the gear <NUM> from moving beyond the first predefined range after the gear <NUM> is rotated such that the rotatable member <NUM> is locked in the second axial position <NUM> to apply a preload tension.

In some implementations in which the rotatable member <NUM> is lockable to the delimiter member <NUM>, when the rotatable member <NUM> is locked to the delimiter member <NUM>, the gear <NUM> is moved from the second predefined range back to the first predefined range such that the gear <NUM> can be driven to roll the distal end component. As a result, the gear <NUM> is drivable to cause the rolling motion of the distal end component while a preload tension is applied to the flexible tensioning element <NUM>.

Referring to <FIG>, in some implementations, the gear <NUM> contacts a first lateral portion <NUM> of the rotatable member <NUM> to rotate the rotatable member <NUM> from the first position toward its second position. The gear <NUM> contacts a second lateral portion <NUM> of the rotatable member <NUM> to rotate the rotatable member <NUM> from the second position back toward the first position. In such an example, the gear <NUM> engages the rotatable member <NUM> to reposition the rotatable member <NUM> toward the second position to apply the operating preload tension to flexible tensioning element <NUM>. The gear <NUM> is also able to engage the rotatable member <NUM> to move the rotating member back toward the first position such that the preload tension is released.

<FIG> depicts another example of a dynamic preload tensioner <NUM>. The dynamic tensioner <NUM> includes a rotatable cam <NUM>. The rotatable cam <NUM> is, for instance, coupled to a drive component of the surgical instrument such that the rotatable cam <NUM> rotates when the drive component is driven. In some cases, the rotatable cam <NUM> rotates relative to a chassis of surgical instrument. A surface <NUM> of the rotatable cam <NUM> engages a flexible tensioning element 806b to change the path of the flexible tensioning element 806b when the rotatable cam <NUM> is rotated. In some implementations, the surface <NUM> of the rotatable cam <NUM> engages each of multiple flexible tensioning elements 806a-806d when the rotatable cam <NUM> is rotated (i.e., for any rotation angle of the cam, the shape of the cam surface that engages elements 806a and 806d causes the same path length change as path length change caused by the shape of the cam surface that engages elements 806b and 806c). The rotatable cam <NUM> applies transverse loads on the flexible tensioning elements 806a-806d to deflect the flexible tensioning elements 806a-806d, thereby adjusting the paths of the flexible tensioning elements 806a-806d. In some cases, the surface <NUM> of the rotatable cam <NUM> is elliptical.

<FIG> depicts an example of a dynamic preload tensioner <NUM> that includes a tensioning plate <NUM> pivotably mounted to the chassis <NUM> of the surgical instrument. The tensioning plate <NUM> is, for example, rotatable about a pin <NUM> on the chassis <NUM>. When the tensioning plate <NUM> is rotated relative to the chassis <NUM>, a path of a flexible tensioning element is changed.

In some implementations, the flexible tensioning element is routed from a gimbal <NUM> inward and through an aperture in tensioning plate <NUM>, and then into the tubular member <NUM> to the distal end component of surgical instrument. The flexible tensioning element bears against the side of the aperture in tensioning plate <NUM>, and as the tensioning plate <NUM> rotates upward, the point at which the tensioning element bears against the side of the aperature moves upward, and so a path of the flexible tensioning element is adjusted.

In some implementations, flexible tensioning elements are routed through the gimbal. In this regard the gimbal changes the path length as it rotates and so imparts an actuating tension to the desired tensioning element.

In some implementations, rather than being routed through the gimbal <NUM>, flexible tensioning elements are connected to the gimbal <NUM>. In this regard, proximal ends of the flexible tensioning elements are moved away from the distal end component when the gimbal <NUM> rotates, thereby increasing length of the path for the desired tensioning elements to actuate the distal end component.

Whether the flexible tensioning element are routed through the gimbal <NUM> or is connected to the gimbal <NUM>, the dynamic preload tensioner <NUM> can be operated to adjust a path of the flexible tensioning element and adjust a preload tension on the tensioning element. To rotate the tensioning plate <NUM> around the pin <NUM>, the dynamic tensioner <NUM> includes, for example, as shown in <FIG>, a rotatable member <NUM> that engages the tensioning plate <NUM>. As the rotatable member <NUM> rotates, a ramp formed on rotatable member <NUM> engages the tensioning plate <NUM> such that the tensioning plate <NUM> pivots about the pin <NUM>, and thereby lengthens the path of the flexible tensioning element. A drive component <NUM> of the surgical instrument, in some cases, is driven by the drive system of the manipulator to rotate the rotatable member <NUM>.

In some implementations, to steer the distal end component, the drive system, e.g., of the manipulator, operates lead screws 916a, 916b, and 916c. The lead screws 916a, 916b, 916c, when operated, rotate arms 918a, 918b, 918c, respectively, such that the gimbal <NUM> pivots relative to the chassis <NUM>. As the gimbal <NUM> pivots, the gimbal <NUM> bears against the flexible tensioning elements to adjust the paths of the flexible tensioning elements, thereby causing the flexible tensioning elements to experience tension. The multiple flexible tensioning elements are drivable by the lead screws 916a, 916b, 916c to move the distal end component in multiple degrees of freedom. Alternatively or additionally, the drive system drives a gear system <NUM> to roll the distal end component.

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made.

In some implementations, the preload tension applied to the flexible tensioning element is controlled during a surgical operation. For example, while the distal end component is being steered during the surgical operation by using a subset of the drive outputs of the drive system of the manipulator, another drive output is operable to adjust the preload tension applied to the flexible tensioning element without steering the distal end component. The surgical instrument includes, for example, of one of the dynamic preload tensioners described herein, and the preload tension is applied before the distal end component is steered for the surgical operation.

In some implementations, the preload tension is adjusted during a surgical operation as loads applied to the distal end component vary during the surgical operation. As the loads on the distal end component increase due to contact with patient tissue, for example, the preload tension is increased. In cases in which the loads on the distal end component are low, e.g., when the distal end component is being steered in space absent contact with patient tissue, the dynamically adjustable preload tension is decreased. In some implementations, the surgical instrument is a surgical stapler system, and the dynamically adjustable preload tension is increased when the stapler system is to be clamped.

In some implementations, the dynamic preload tensioner for a flexible tensioning element includes the drive component operated to steer the distal end component by using the flexible tensioning element. The flexible tensioning element is, for example, twisted to change a path of the flexible tensioning element. In the example shown in <FIG>, a dynamic preload tensioner <NUM> includes a first portion <NUM> and a second portion <NUM>. The dynamic tensioner <NUM> is, for example a rotatable capstan in which the first portion <NUM> has a first diameter, and the second portion <NUM> has a second diameter, the first diameter being smaller than the second diameter. At a distal end, the flexible tensioning element <NUM> is attached to a distal end component. At a proximal end, the flexible tensioning element <NUM> is attached to the dynamic tensioner <NUM> such that it can be driven by the dynamic tensioner <NUM> and such that it can be selectively wrapped around the different portions <NUM>, <NUM>. The dynamic tensioner <NUM> includes a drive component <NUM>, e.g., the drive component 104a, that can be driven to apply tension to the flexible tensioning element <NUM> to steer the distal end component to which the flexible tensioning element <NUM> is coupled.

When the drive component <NUM> is driven by, for example, the drive system of the manipulator, the dynamic tensioner <NUM> is rotated. To steer the distal end component, the dynamic tensioner <NUM> is rotated to apply tension to the flexible tensioning element <NUM>. To apply the adjustable preload tension to the flexible tensioning element <NUM>, the flexible tensioning element <NUM> is wrapped around a selected portion of the capstan. When the flexible tensioning element <NUM> is wrapped around the second portion <NUM>, a path of the flexible tensioning element <NUM> is adjusted such that a preload tension is applied to the flexible tensioning element <NUM>. In some cases, in an initial state of the surgical instrument, the flexible tensioning element <NUM> is wrapped around the first portion <NUM>. To add preload tension to the flexible tensioning element, the flexible tensioning element <NUM> is wrapped around the second portion <NUM>. In some cases, to add preload tension to the flexible tensioning element <NUM>, the flexible tensioning element <NUM> is moved from an initial state in which it is wrapped around the first portion <NUM> to an operating state in which it is wrapped around both the first portion <NUM> and the second portion <NUM>. In some implementations, if the flexible tensioning element <NUM> is driven to move the distal end effector in a first direction along a degree of freedom and another flexible tensioning element is driven to move the distal end effector in a second direction along the degree of freedom, the other flexible tensioning element is attached to separate drive component and dynamic tensioner.

As shown in <FIG>, in some implementations, rather than having multiple portions having different diameters, a dynamic preload tensioner <NUM> includes a horizontal section <NUM> having an oblong profile, an oval profile, and/or a non-circular profile. The dynamic tensioner <NUM> is mounted to a chassis of the surgical instrument such that the dynamic tensioner <NUM> is rotatable about a center of rotation <NUM>. A drive component (not shown) is drivable by a drive system of a surgical manipulator as described above to rotate the dynamic preload tensioner <NUM>. The horizontal section <NUM> includes, for instance, a first zone <NUM> and a second zone <NUM>. The first zone <NUM> has a profile with a distance to the center of rotation <NUM> that varies along its length. The second zone <NUM>, for instance, has a circular profile with constant distance between the profile and the center of rotation <NUM> of the horizontal section <NUM>.

The flexible tensioning element <NUM> is attached to the dynamic tensioner <NUM> such that it wraps around the horizontal section <NUM> of the capstan. To add preload tension to the flexible tensioning element <NUM>, the flexible tensioning element <NUM> is wrapped around the first zone <NUM>. A path of the flexible tensioning element <NUM> changes, e.g., a length of the path decreases, when the flexible tensioning element <NUM> is wrapped around the first zone <NUM>. In an initial action, the flexible tensioning element <NUM> is wrapped around the first zone <NUM> to increase the preload tension from a first value to a second value. In an operating state in which preload tension has been added to the flexible tensioning element <NUM>, the flexible tensioning element <NUM> is wrapped around both the first zone <NUM> and the second zone <NUM>. The flexible tensioning element <NUM> extends away from the dynamic tensioner <NUM> beginning at the second zone <NUM> such that the amount of length of the flexible tensioning element <NUM> that is wound onto the dynamic tensioner <NUM> is proportional to the amount of rotation of the dynamic tensioner <NUM>. In contrast, when the flexible tensioning element <NUM> extends away from the dynamic tensioner <NUM> beginning at the first zone, a greater amount of length of the flexible tensioning element is wound onto the dynamic tensioner <NUM> given an amount of rotation of the dynamic tensioner <NUM>. The dynamic tensioner <NUM> is rotated to drive the flexible tensioning element from the initial state to the operation state. In some implementations, if the flexible tensioning element <NUM> is driven to move the distal end effector in a first direction along a degree of freedom and another flexible tensioning element is driven to move the distal end effector in a second direction along the degree of freedom, the other flexible tensioning element is attached to separate drive component and dynamic tensioner.

While the drive system of the manipulator has been described as operating the dynamic preload tensioner, in some implementations, a manually operable preload tensioning tool is operated, e.g., by a nurse, a clinician, or a surgeon, to operate the dynamic tensioner. The tensioning tool is, for example, a switch, a knob, or other device on an exterior surface of the chassis of the surgical instrument that the operator manually operates the dynamic tensioner to adjust the path of the flexible tensioning element. When operated, the tensioning tool is lockable in place such that the preload tension provided by the adjusted path of the flexible tensioning element is maintained. The tensioning tool is, in some cases, coupled to a mechanism for a dynamic tensioner described in the examples herein. The tensioning tool, for instance, is substituted for the drive component such that the preload tension is added through manual operation of the tensioning tool rather than through operation of an actuator coupled to the drive component.

In some implementations, the dynamic preload tensioner includes a pin movably mounted to the chassis and engageable with the flexible tensioning element to change the path of the flexible tensioning element when the pin is moved relative to the chassis. The pin, for instance, applies a transverse load on the flexible tensioning element that bends the flexible tensioning element at a location at which the pin contacts the flexible tensioning element. The bending of the flexible tensioning element changes a path of the flexible tensioning element, e.g., increases a path length. The path change thereby adds a preload tension to the flexible tensioning element.

The examples presented herein indicate that the dynamic tensioner, in some cases, is lockable such that the preload tension added using the dynamic tensioner can be maintained. In some implementations, the dynamic tensioner is lockable at one of several discrete positions. The dynamic tensioner, for instance, includes a ratcheting mechanism that adds preload tension to the flexible tensioning element as the ratcheting mechanism is advanced. In some cases, the ratcheting mechanism is resettable to reduce the preload tension on the flexible tensioning element.

In some implementations, the dynamic preload tensioner rotates the tubular member relative to the chassis. For instance, referring back to <FIG>, an alternative dynamic tensioner causes the tubular member <NUM> to rotate relative to the chassis <NUM> about a point at which the tubular member <NUM> and the chassis <NUM> are connected. At the location at which the flexible tensioning element <NUM> enters the tubular member <NUM>, the surgical instrument <NUM> includes, for example, a bearing surface that the flexible tensioning element <NUM> engages when the tubular member <NUM> is rotated relative to the chassis <NUM>. The engagement between the bearing surface and the flexible tensioning element <NUM> changes the path of the flexible tensioning element <NUM>, e.g., increases a path length.

In some implementations, the preload tension is added to the flexible tensioning element only when the surgical instrument is mounted to the manipulator. The controller, for example, only operates the drive system of the manipulator upon detecting that the surgical instrument has been mounted to the manipulator. In some cases, the driven interface assembly of the manipulator engages with actuation levers on the surgical instrument. The actuation levers, upon being actuated, activate the dynamic preload tensioner to add the preload tension to the flexible tensioning element. In some implementations, the driven interface assembly of the manipulator includes a sensor to detect engagement with the surgical instrument. Upon detecting engagement of the driven interface assembly of the manipulator with the surgical instrument, the sensor transmits a signal to the controller, which in turn operates the actuator to drive the drive component coupled to the dynamic tensioner.

While locking mechanisms and techniques have been described with respect to some implementations, in some cases, the controller of the manipulator operates the drive output to maintain the position of the dynamic tensioner and hence maintain the preload tension in the flexible tensioning element. In cases in which the dynamic tensioner is coupled to a drive component driven by a drive output of the manipulator, the controller locks the actuator to inhibit rotation of the drive component. The controller, for instance, locks the actuator in response to determining that the tension in the flexible tensioning element is above a predefined threshold.

Claim 1:
A computer-assisted surgical system (<NUM>) comprising a surgical instrument (<NUM>), the surgical instrument comprising:
a chassis (<NUM>) at a proximal end (<NUM>) of the surgical instrument (<NUM>);
a distal end component (<NUM>) at a distal end (<NUM>) of the surgical instrument (<NUM>);
a plurality of first drive components (104a, 1204a) mounted in the chassis (<NUM>);
a second drive component (104b, 1204b) mounted in the chassis (<NUM>);
a plurality of flexible tensioning elements (<NUM>, <NUM>) each coupled between a corresponding one of the plurality of first drive components (104a, 1204a) and the distal end component (<NUM>) and each extending along a corresponding path; and
a dynamic preload tensioner (<NUM>) mounted in the chassis (<NUM>) and coupled to be driven by the second drive component (104b, 1204b) to move relative to the chassis (<NUM>) and as a result change the corresponding path of and apply a preload tension in each of the plurality of flexible tensioning elements (<NUM>, <NUM>) as the dynamic preload tensioner (<NUM>) moves relative to the chassis (<NUM>).