Apparatus and method for compact redundant inductive force sensor

Abstract

A medical device includes a mechanical structure and a force sensor unit. The force sensor unit includes a mounting bracket, a first rod, a second rod, a first magnet, a second magnet, a first coil coupled to the mounting bracket, and a second coil coupled to the mounting bracket. The first rod and the second rod each have a central axis defined between a proximal portion and a distal portion of the respective first rod and second rod. The central axis of the second rod is non-coaxial with the central axis of the first rod. The first magnet is coupled to the first rod and translates within the first coil along the central axis of the first rod. Similarly, the second magnet is coupled to the second rod and translates within the second coil along the central axis of the second rod.

Description

[0001] Related applications

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 077,833 (filed September 14, 2020), entitled “Devices and Method for Compact, Redundant Inductive Force Sensor,” the disclosure of which is incorporated herein by reference in its entirety.

[0003] This patent application relates to PCT International Patent Application No. PCT / US2020 / 050696 entitled “COMPACT, DIFFERENTIAL, COAXIAL INDUCTIVE FORCE SENSOR” (filed September 14, 2020) and U.S. Provisional Patent Application No. 62 / 901,729 entitled “COMPACT, DIFFERENTIAL, COAXIAL INDUCTIVE FORCE SENSOR” (filed September 17, 2019), the entire contents of which are incorporated herein by reference. Technical Field

[0004] The embodiments described herein relate to force-sensing mechanical structures, more specifically to medical devices, and even more specifically to instruments for minimally invasive surgical procedures. More specifically, the embodiments described herein relate to medical devices including a force sensor unit coupled to a mechanical structure of the medical device and used to measure the axial force applied to an end effector of the medical device during a surgical procedure. Background Technology

[0005] Known techniques for minimally invasive medical interventions employ instruments to manipulate tissue, which can be controlled manually or via a handheld or mechanically grounded telemedicine system (“teleoperative system”) operated with at least partial computer assistance. Many known medical devices include therapeutic or diagnostic end effectors (e.g., nickels, cutting tools, or cauterization tools) mounted on an optional wrist mechanism at the distal end of an axis. In a medical procedure, the end effector, wrist mechanism, and distal end of the axis are inserted into a small incision or natural orifice in the patient to position the end effector at a working site within the patient's body. The optional wrist mechanism can be used to change the position and orientation of the end effector relative to the axis to perform the desired procedure at the working site. In known devices, the overall motion of the device provides mechanical degrees of freedom (DOF) for the movement of the end effector, and the wrist mechanism typically provides the desired DOF for the movement of the end effector relative to the axis of the device. For example, for forceps or other grasping tools, known wrist mechanisms are capable of changing the pitch and yaw of the end effector relative to the axis. The wrist may optionally provide a rolling DOF for the end effector, or a rolling DOF may be achieved via a rolling axis. The end effector may optionally have additional mechanical DOFs, such as gripper or blade movement. In some cases, the mechanical DOFs of the wrist and the end effector can be combined. For example, U.S. Patent No. 5,792,135 (filed May 16, 1997) discloses a mechanism that combines a wrist and an end effector gripper DOF.

[0006] To enable the wrist mechanism and end effector to perform desired movements, known instruments include a mechanical connector (e.g., a cable) that extends through the axis of the instrument and connects the distal wrist mechanism to a proximal mechanical structure for moving the connector to operate the wrist mechanism. In remote surgical systems, the mechanical structure is typically motor-driven and operatively coupled to a processing system to provide a user interface for clinical users (e.g., surgeons) to control the entire instrument as well as its components and functions.

[0007] Force-sensing surgical instruments are known to provide associated tactile feedback to clinical users during medical procedures, in conjunction with associated remote surgical systems, resulting in greater immersion, realism, and intuitiveness for the clinician performing the procedure. For effective tactile rendering and accuracy, force sensors are placed on the medical device. One approach includes a force sensor unit attached to and / or incorporated into the proximal mechanical structure of the medical device and used to measure axial forces applied to the end effector of the medical device. These force measurements are taken at or near the device axis and are used to generate tactile feedback forces at the input of a master control device, providing the user with an indication of the forces applied by the medical device to, for example, patient tissue. That is, the force applied by the instrument to an object such as tissue or sutures is indicated by corresponding reaction forces on the instrument from these objects, and the sensed reaction forces are transmitted to the user as a tactile sensation.

[0008] Improvements to force sensor systems lead to more accurate force measurements, which in turn result in more accurate tactile feedback. For example, including multiple sensors to measure a single force parameter (e.g., the axial force applied to an end effector) can improve measurement accuracy (e.g., by generating average measurements or by allowing subtraction of common patterns) and allow operation even in the event of a sensor failure. However, due to the mechanical constraints and overall device size limitations required for minimally invasive medical devices, including additional sensors competes for limited space. Force sensor systems must not only be as efficient as possible but also conform to the spatial design constraints of the force-bearing object, such as a medical device.

[0009] Therefore, there is a need for improved force sensing capabilities, which in turn can improve tactile feedback, especially within the spatial constraints of minimally invasive surgical instruments. Summary of the Invention

[0010] This summary introduces certain aspects of the embodiments described herein to provide a basic understanding. This summary is not an exhaustive overview of the subject matter of the invention, and it is not intended to identify key or essential elements or to depict the scope of the subject matter of the invention.

[0011] In some embodiments, an apparatus includes a mechanical structure and a force sensor unit coupled to the mechanical structure. The force sensor unit includes a mounting bracket, a first rod, a second rod, a first magnet, a second magnet, a first coil coupled to the mounting bracket, and a second coil coupled to the mounting bracket. The first rod includes a distal portion and a proximal portion, and a central axis of the first rod is defined between the proximal and distal portions. The second rod includes a distal portion and a proximal portion, and a central axis of the second rod is defined between the proximal and distal portions. The central axis of the second rod is not coaxial with the central axis of the first rod. The first magnet is coupled to the first rod, and the second magnet is coupled to the second rod. The first magnet translates within the first coil along the central axis of the first rod, and the second magnet translates within the second coil along the central axis of the second rod.

[0012] In some embodiments, the device further includes a shaft coupled to a mechanical structure. The shaft is operatively coupled to a first rod and a second rod such that translational movement of the shaft relative to the mechanical structure moves the first rod within a first coil and moves the second rod within a second coil. In some embodiments, the shaft includes a proximal end and a distal end, and a central axis of the shaft is defined between the proximal and distal ends. The shaft is operatively coupled to the first rod and the second rod such that the shaft is rotatable about its central axis without moving either the first or second rod.

[0013] In some embodiments, the device further includes a link coupled to a shaft, wherein a first rod and a second rod are coupled to the link. The link includes a roller drive receiver in which the shaft is rotatable relative to the link without moving the first or second rod. In some embodiments, the shaft includes a proximal end and a distal end, and a central axis is defined between the proximal and distal ends of the shaft. A first signal is generated by a first coil and associated with the position of a first magnet within the first coil, and a second signal is generated by a second coil and associated with the position of a second magnet within the second coil. The first signal from the first coil and the second signal from the second coil are associated with a linear displacement of the shaft along the central axis of the shaft. In some embodiments, the linear displacement is proportional to a force applied to the shaft in a direction along the central axis of the shaft.

[0014] In some embodiments, the shaft includes a proximal end and a distal end, and the central axis of the shaft is defined between the proximal and distal ends. A first coil and a second coil are each secured to a mounting bracket such that the central axis of the shaft is centered between the central axes of the first and second coils. In some embodiments, the central axes of the first and second coils are parallel to the central axis of the shaft. In some embodiments, the first coil has a first height, the second coil has a second height, and the first height is equal to the second height.

[0015] In some embodiments, the shaft includes a proximal end and a distal end, and a central axis is defined between the proximal and distal ends of the shaft. The device also includes a linkage device coupled to the shaft and a mechanical structure. The linkage device includes a spring configured to displace proportionally to a force applied to the shaft in a direction along the central axis of the shaft.

[0016] In some embodiments, a first signal generated by a first coil is associated with the position of a first magnet within the first coil, and a second signal generated by a second coil is associated with the position of a second magnet within the second coil. The force sensor unit includes a microprocessor configured to receive the first and second signals. In some embodiments, the shaft includes a proximal end and a distal end, and a central axis is defined between the proximal and distal ends of the shaft. In such embodiments, the first signal has a first frequency, the second signal has a second frequency, and the microprocessor is configured to execute instructions to determine a measure of the force on the shaft along the central axis of the shaft based on the first and second frequencies.

[0017] In some embodiments, the medical device includes an instrument shaft and a medical end effector coupled to the distal end of the shaft. A mechanical structure is coupled to the proximal end of the shaft, and a force sensor unit is coupled to the mechanical structure and the instrument shaft. The force sensor unit includes a first coil wound about a first coil axis, a second coil wound about a second coil axis, a first rod, and a second rod. The instrument shaft axis is defined between the proximal and distal ends of the instrument shaft and extends between the first coil axis and the second coil axis. The first rod is operatively coupled to the instrument shaft and includes a first magnet positioned to move within the first coil axis as the instrument shaft moves along the instrument shaft axis, and the second rod is operatively coupled to the instrument shaft and includes a second magnet positioned to move within the second coil axis as the instrument shaft moves along the instrument shaft axis.

[0018] In some embodiments, the medical device further includes a linkage device coupled to the shaft and the mechanical structure. The linkage device includes a spring configured to displace proportionally to a force applied to the shaft in a direction along the central axis of the shaft.

[0019] In some embodiments, a first signal generated by a first coil is associated with the position of a first magnet within the first coil, and a second signal generated by a second coil is associated with the position of a second magnet within the second coil. The force sensor unit includes a microprocessor configured to receive the first and second signals. In some embodiments, the first signal has a first frequency, the second signal has a second frequency, and the microprocessor is configured to execute instructions to determine a measurement of a force on the shaft along its central axis based on the first and second frequencies. In some embodiments, the first signal from the first coil and the second signal from the second coil are associated with a linear displacement of the shaft along its central axis.

[0020] In some embodiments, the medical device further includes a linkage device coupled to the shaft and the mechanical structure, and the linkage device includes a spring. The spring is configured to displace proportionally to a force applied to the shaft in a direction along the central axis of the shaft. In some embodiments, a first central axis of the first rod and a second central axis of the second rod are parallel to the central axis of the shaft.

[0021] In some embodiments, the medical device includes an instrument support structure, an instrument shaft, and a force sensor unit. The instrument shaft includes a proximal end and a distal end, with an axis defined between the proximal and distal ends. The force sensor unit includes a linkage coupled between the instrument support structure and the proximal end of the instrument shaft, a first coil wound around a first coil axis, a second coil wound around a second coil axis different from the first coil axis, a first magnet at least partially within the first coil, and a second magnet at least partially within the second coil. The first coil, the second coil, the first magnet, and the second magnet are positioned between the linkage of the instrument support structure and the force sensor unit such that translation of the instrument shaft along its axis relative to the instrument support structure causes relative movement between the first magnet and the first coil along the first coil axis, and relative movement between the second magnet and the second coil along the second coil axis.

[0022] In some embodiments, the first coil and the second coil are fixed relative to the instrument support structure. In some embodiments, the linkage includes a rotary joint having a rotation axis coaxial with the instrument shaft axis, and the instrument shaft is coupled to the linkage of the force sensor unit to rotate relative to the instrument support structure about the rotation axis at the joint.

[0023] In some embodiments, the medical device includes a proximal mechanical structure, a distal mechanism, and a connector. The distal mechanism is coupled to the distal end of an instrument axis and includes a movable part. The proximal mechanical structure includes an instrument support structure and an actuator input mounted to move relative to the instrument support structure. The connector is coupled between the actuator input and the movable part of the distal mechanism. Attached Figure Description

[0024] Figure 1 is a plan view of a minimally invasive remote surgical system according to an embodiment of a medical procedure such as a surgical operation.

[0025] Figure 2 yes Figure 1 A perspective view of the optional auxiliary units of the minimally invasive remote surgical system shown.

[0026] Figure 3 yes Figure 1 A perspective view of the user console of the minimally invasive remote surgical system shown.

[0027] Figure 4 yes Figure 1 The front view shown is of a manipulator unit comprising multiple instruments for a minimally invasive remote surgical system.

[0028] Figure 5 This is a schematic diagram of a medical device including a force sensor unit according to an embodiment.

[0029] Figure 6A This is a schematic diagram of a portion of a medical device according to an embodiment.

[0030] Figure 6B This is a graph illustrating the linear range of the coil inductance and the rod within the force sensor unit of the medical device according to an embodiment.

[0031] Figure 6C This is a schematic diagram of a portion of a medical device according to an embodiment.

[0032] Figure 7A This is a perspective view of a medical device according to an embodiment.

[0033] Figure 7B It includes a locking handle coupled to the outer shaft. Figure 7A A perspective view of the proximal portion of a medical device.

[0034] Figure 8 yes Figure 7A A magnified perspective view of the distal portion of a medical device.

[0035] Figure 9 yes Figure 7A Bottom view of the mechanical structure of the medical device.

[0036] Figure 10 yes Figure 7B A side view of the proximal portion of a medical device.

[0037] Figure 11 yes Figure 7A A perspective view of the mechanical structure of a medical device, with the selection component removed for illustrative purposes.

[0038] Figure 12 yes Figure 7A A side view of the mechanical structure and axes of the medical device, with the selection component removed for illustrative purposes.

[0039] Figure 13 yes Figure 7A A side view of the linkage and axis of the medical device, in which the selection component has been removed for illustrative purposes.

[0040] Figure 14 yes Figure 13 A partial exploded view of the linkage device and shaft.

[0041] Figure 15 and Figure 16 They are Figure 7A Different perspective views of the mechanical structure of the medical device, in which selected components have been removed for illustrative purposes.

[0042] Figure 17 yes Figure 7A A perspective view of the linkage of the force sensor unit in a medical device.

[0043] Figure 18 yes Figure 7A A side view of the mechanical structure of a medical device, in which the selection component has been removed for illustrative purposes and the spring and shaft are shown in a first neutral position.

[0044] Figure 19 and Figure 20 Each is Figure 7A A side view of the mechanical structure of a medical device, wherein the selection component has been removed for illustrative purposes and is shown in the second upper position. Figure 19 ) and the third lower position ( Figure 20 ) axis.

[0045] Figure 21 It is coupled to Figure 7A A perspective view of the axis of the roller drive receiver and roller carrier of a medical device.

[0046] Figure 22 It is coupled to Figure 21 Exploded perspective view of the shaft of the roller drive receiver and roller carrier of the medical device.

[0047] Figure 23 yes Figure 7A A side view of the mechanical structure of a medical device, in which the selection component has been removed for illustrative purposes and the shaft coupled to the roller drive receiver is shown.

[0048] Figure 24 yes Figure 7AAn end perspective view of the mechanical structure of a medical device, in which the selection component has been removed for illustrative purposes.

[0049] Figure 25 yes Figure 7A An exploded view of the coil assembly and connecting rod of the force sensor unit in a medical device.

[0050] Figure 26 and Figure 27 yes Figure 7A Side view of the coil assembly of the force sensor unit in a medical device ( Figure 26 ) and perspective ( Figure 27 ).

[0051] Figure 28 and Figure 29 yes Figure 7A Bottom perspective view of the coil assembly of the force sensor unit in the medical device ( Figure 28 ) and top perspective ( Figure 29 ).

[0052] Figure 30 yes Figure 7A Bottom view of the coil assembly of the force sensor unit in the medical device.

[0053] Figure 31 yes Figure 7A A side view of the coil assembly of the force sensor unit in a medical device.

[0054] Figure 32 yes Figure 7A A side view of the rod of the coil assembly of the force sensor unit in a medical device.

[0055] Figure 33 This is a schematic diagram of a portion of a force sensor unit according to an embodiment. Detailed Implementation

[0056] The embodiments described herein can be advantageously used in a variety of force sensor applications, such as for grasping, cutting, and manipulating operations associated with minimally invasive surgery. The embodiments described herein can also be used in a variety of non-medical applications, such as remote operating systems for search and rescue, remotely controlled diving equipment, aerial equipment, and automobiles. The medical device or apparatus of this application is capable of movement with three or more degrees of freedom (DOF). For example, in some embodiments, the end effector of the medical device can move relative to the device body with three mechanical degrees of freedom (e.g., pitch, yaw, and roll (axis roll)). The end effector itself may also have one or more mechanical DOFs, such as two grippers (each gripper rotating relative to a U-clamp (2 DOFs)) and a distal U-clamp (which rotates relative to a proximal U-clamp (one DOF)). Thus, in some embodiments, the medical device or apparatus of this application is capable of movement with six DOFs. The embodiments described herein can also be used to determine the forces acting on (or acted upon by) the distal portion of the device during use.

[0057] The medical device described herein includes a force sensor unit comprising a compact inductive force sensor to measure forces applied axially to an end effector of the medical device in the z-axis direction. As described herein, two inductive coils are each wound around a polymer cylinder and a magnet (e.g., a ferrite bead, an EMI (electromagnetic interference) suppressor bead, a nickel-zinc bead, etc.; the term "magnet" as used herein is described in more detail below), the polymer cylinder and the magnet being held by a rod movably positioned within each coil. As the magnet moves axially within its respective coil, the inductance of each coil changes. This change in inductance of each coil can be used to measure a change in the device's axial position, which can be translated into a z-axis force measurement. The embodiments described herein provide enhanced linear force output (e.g., within ±2.0 mm (0.080 inches)) and elimination of temperature effects. The compact inductive force sensor described herein provides redundancy in force measurement by using two inductive coils positioned side-by-side. This arrangement also reduces the overall height of the force sensor, thereby saving space within the mechanical structure. Furthermore, in some embodiments, the coil and magnet design (e.g., the length, width, and wire thickness of the coil, together with the size of the rod and the magnet) can be optimized to ensure that the rod with the magnet is centered inside the coil (e.g., in some embodiments, there is a gap of approximately 1.33 mm (0.050 inches) between the inner surface of the coil and the outer surface of the rod with the magnet). The embodiments described herein can also produce increased linear travel of the force sensor. Additionally, to avoid the sensor picking up erroneous force signals, in some embodiments, two induction coils are mechanically grounded as spring elements to the same rigid component of the medical device, the spring elements being part of a linkage mechanism for converting force into a displacement measurement (described in more detail below).

[0058] As used herein, the term “about” when used in conjunction with a reference number indicates a reference number plus or minus a maximum of 10%. For example, the language “about 50” covers a range of 45 to 55. Similarly, the language “about 5” covers a range of 4.5 to 5.5.

[0059] The term "flexible" in relation to parts (such as mechanical structures, components, or component assemblies) should be interpreted broadly. Essentially, the term means that a part can be repeatedly bent and return to its original shape without damage. Some flexible parts can also be elastic. For example, a part (such as a flexure) is said to be elastic if it has the ability to absorb energy during elastic deformation and then release the stored energy upon unloading (i.e., return to its original state). Many "rigid" objects have a slight inherent elastic "bending" due to material properties, although these objects are not considered "flexible" as used herein.

[0060] As used in this specification and the appended claims, the term "distal" refers to the direction toward the working part, while the term "proximal" refers to the direction away from the working part. Thus, for example, the end of the tool closest to the target tissue would be the distal end of the tool, while the end opposite the distal end (i.e., the end manipulated by the user or coupled to the actuation shaft) would be the proximal end of the tool.

[0061] Furthermore, the choice of specific terms used to describe one or more embodiments and optional elements or features is not intended to limit the invention. For example, spatially relative terms—such as “below,” “under,” “lower,” “above,” “upper,” “proximal,” “farthest,” and the like—may be used to describe the relationship of one element or feature to another element or feature as shown in the figures. These spatially relative terms are intended to cover different positions (i.e., translational placement) and orientations (i.e., rotational placement) of the device in use or operation, in addition to the positions and orientations shown in the figures. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features will be “above” or “above” other elements or features. Thus, the term “below” can include both above and below positions and orientations. The device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are interpreted accordingly. Similarly, descriptions of movement along various axes (translation) and about various axes (rotation) include various spatial device positions and orientations. The combination of body position and orientation defines body posture.

[0062] Similarly, geometric terms such as “parallel,” “perpendicular,” “circular,” or “square” are not intended to require absolute mathematical precision unless the context otherwise specifies. Instead, such geometric terms allow for variations arising from manufacturing or equivalent functions. For example, if an element is described as “circular” or “generally circular,” then this description still includes parts that are not precisely circular (e.g., slightly rectangular or polygonal parts).

[0063] Furthermore, the singular forms “a,” “an,” and “the” are intended to also include the plural forms, unless the context otherwise requires. The terms “comprising,” “including,” “having,” and similar descriptions specify the presence of the stated features, steps, operations, elements, components, etc., but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, or groups.

[0064] Unless otherwise stated, the terms equipment, medical device, instrument and its variants are used interchangeably.

[0065] Various aspects of the present invention are primarily based on the use of a device commercially available from Intuitive Surgical, Inc., Sunnyvale, California. The implementation method of the surgical system is described. An example of such a surgical system is da. Surgical system (model IS4000) and da Surgical system (model IS4200). However, those skilled in the art will understand that the inventive aspects disclosed herein can be embodied and implemented in various ways, including computer-assisted, non-computer-assisted, and hybrid combinations of manual and computer-assisted embodiments and implementations. The embodiments of the surgical systems (e.g., models IS4000, IS3000, IS2000, and IS1200) are presented by way of example only and should not be considered as limiting the scope of the inventive aspects disclosed herein. Where applicable, inventive aspects can be embodied and implemented in relatively small handheld manual operating devices and relatively large systems with additional mechanical support (i.e., on devices that are mechanically grounded or ungrounded relative to a world reference frame).

[0066] Figure 1This is a floor plan illustration of a computer-aided remote operating system. The diagram shows a medical device, a minimally invasive robotic surgery (MIRS) system 1000 (also referred to herein as a minimally invasive remote surgical system), for performing minimally invasive diagnostic or surgical procedures on a patient P lying on an operating table 1010. The system may have any number of components, such as a user control unit 1100 for use by a surgeon or other skilled clinician S during the procedure. The MIRS system 1000 may also include a manipulator unit 1200 (generally referred to as a surgical robot) and optional assistive equipment units 1150. The manipulator unit 1200 may include an arm assembly 1300 and a tool assembly removably coupled to the arm assembly. The manipulator unit 1200 can manipulate at least one removably coupled instrument 1400 through a minimally invasive incision or natural orifice in the patient P's body, while the surgeon S observes the surgical site and controls the movement of the instrument 1400 via the control unit 1100. Images of the surgical site are obtained via an endoscope (not shown) (such as a stereoscopic endoscope), which can be manipulated by the manipulator unit 1200 to orient the endoscope. The auxiliary equipment unit 1150 can be used to process images of the surgical site for subsequent display to the surgeon S via the user control unit 1100. The number of instruments 1400 used at one time typically depends on the diagnostic or surgical procedure and space constraints within the operating room, as well as other factors. If one or more instruments 1400 in use need to be replaced during the procedure, the assistant removes the instrument 1400 from the manipulator unit 1200 and replaces it with another instrument 1400 from the tray 1020 in the operating room. Although shown as being used with instrument 1400, any instrument described herein can be used with the MIRS 1000.

[0067] Figure 2 This is a perspective view of the control unit 1100. The user control unit 1100 includes a left-eye display 1112 and a right-eye display 1114 for presenting the surgeon S with a coordinated stereoscopic view of the surgical site capable of depth perception. The user control unit 1100 further includes one or more input control devices 1116, which in turn enable ( Figure 1 The manipulator unit 1200 (shown) manipulates one or more tools. The input control device 1116 provides at least the same degrees of freedom as the associated instruments 1400 to provide a remote presentation to the surgeon S, or to provide the perception that the input control device 1116 is integrated with (or directly connected to) the instruments 1400. In this way, the user control unit 1100 provides the surgeon S with a strong sense of direct control over the instruments 1400. For this purpose, position, force, strain, and / or tactile feedback sensors (not shown) can be utilized to transmit position, force, and tactile sensation from the instruments 1400 back to the surgeon's hand via the input control device 1116.

[0068] User control unit 1100 Figure 1 The surgeon is positioned in the same room as the patient so that he / she can directly monitor the procedure, be physically present if necessary, and speak directly with an assistant rather than via telephone or other communication medium. However, in other embodiments, the user control unit 1100 and the surgeon S may be in different rooms, entirely different buildings, or other remote locations away from the patient to allow for remote surgical procedures.

[0069] Figure 3 This is a perspective view of the auxiliary equipment unit 1150. The auxiliary equipment unit 1150 may be coupled to an endoscope (not shown) and may include one or more processors to process the captured images for subsequent display, such as via a user control unit 1100, or on another suitable display located locally and / or remotely. For example, in the case of using a stereoscopic endoscope, the auxiliary equipment unit 1150 may process the captured images to present a coordinated stereoscopic image of the surgical site to the surgeon S via a left-eye display 1112 and a right-eye display 1114. This coordination may include alignment between opposing images and may include adjusting the stereoscopic working distance of the stereoscopic endoscope. As another example, image processing may include compensating for imaging errors, such as optical aberrations, of the image capture device using previously determined camera calibration parameters.

[0070] Figure 4 A front perspective view of the manipulator unit 1200 is shown. The manipulator unit 1200 includes components (e.g., arms, linkages, motors, sensors, and the like) for manipulating the instrument 1400 and an imaging device (not shown) such as a stereoscopic endoscope for capturing images of the site of the procedure. Specifically, the instrument 1400 and the imaging device can be manipulated via a remote manipulator mechanism having multiple joints. Furthermore, the instrument 1400 and the imaging device are positioned and manipulated through an incision or natural orifice in the patient P in a manner maintained at the incision or orifice by software and / or kinematic remote motion centers. In this way, the incision size can be minimized.

[0071] Figure 5This is a schematic diagram of a medical device 2400 according to an embodiment. In some embodiments, the medical device 2400 or any component thereof may optionally be part of a surgical system for performing surgical procedures, and may include a manipulator unit, a series of kinematic linkages, a series of cannulas, or the like. The medical device 2400 (and any instruments described herein) can be used in any suitable surgical system, such as the MIRS system 1000 shown and described above. The medical device 2400 includes a mechanical structure 2700, a force sensor unit 2800 coupled to or included within the mechanical structure 2700, a shaft 2410 coupled to the mechanical structure 2700, a beam 2810 coupled to the shaft 2410, and an end effector 2460 coupled to the distal portion of the beam 2810. The end effector 2460 may include, for example, a hinged clamp or another suitable surgical tool coupled to a link 2510. In some embodiments, the link 2510 may be included within a wrist assembly having a plurality of articulated links. Shaft 2410 includes a distal portion coupled to a proximal portion of beam 2810. In some embodiments, the distal portion of shaft 2410 is coupled to a proximal portion 2822 of beam 2810 via another coupling component (such as an anchor or coupler, not shown). Shaft 2410 is also movably coupled at its proximal portion to mechanical structure 2700. Mechanical structure 2700 may include components configured to move one or more parts of a surgical instrument, such as, for example, an end effector 2460. Mechanical structure 2700 may be similar to mechanical structure 5700, which is described in more detail below with reference to medical device 5400.

[0072] Typically, during medical procedures, the end effector 2460 comes into contact with anatomical tissue, which may result in forces being applied to the end effector 2460 in the x, y, or z directions, and may also result in torques, such as Figure 5 The torque M shown is approximately along the y-axis. Y In some embodiments, one or more strain sensors (not shown) (which may be strain gauges) may be coupled to beam 2810 to measure strain in beam 2810. The measured beam strain may be used to determine the forces applied to end effector 2460 in the x-axis and y-axis directions. These x-axis and y-axis forces are transverse (e.g., perpendicular to) the z-axis (which is perpendicular to the central axis A of the beam). B Parallel or collinear).

[0073] Force sensor unit 2800 (and any force sensor unit described herein) can be used to measure one or more axial forces applied to end effector 2460 (i.e., forces parallel to the beam's central axis A). B (in the direction of the z-axis). For example, an axial force F applied to the end effector 2460 in the z-axis direction. zThis can cause shaft 2410 to be positioned along its central axis (which is substantially parallel to the beam's central axis A). B Axial displacement in the direction of ) . Axial force F z It can be in the proximal direction (e.g., the reaction force generated by pushing tissue by the end effector) or it can be in the distal direction (e.g., the reaction force generated by pulling tissue grasped by the end effector). As described herein, shaft 2410 can be coupled to mechanical structure 2700 via a biasing mechanism (e.g., a linkage or spring-loaded coupler, not shown) such that the travel of shaft 2410 relative to mechanical structure 2700 can be correlated with the axial force F applied to end effector 2460. z The magnitudes are interrelated. In this way, the distance traveled by measuring the shaft 2410 relative to the mechanical structure 2700 can be used to determine the axial force F. z .

[0074] Force sensor unit 2800 may include any suitable components to isolate axial movement of shaft 2410 (i.e., constrain the shaft such that the measured movement is caused only by axial force F). z Instead of lateral forces along the x-axis and y-axis, frictional forces restrict movement opposite to that of axis 2410 (which leads to the determination of the axial force F). z (error), and provides redundancy for the movement of the measuring shaft 2410. For example, in some embodiments, the force sensor unit 2800 may include a coil assembly, a linkage device, and a microprocessor (each not in the same configuration). Figure 5 (As shown in the diagram). The linkage can be any suitable mechanism that causes the shaft to move by an amount that is related to the applied axial force F. z The shaft 2410 is movably coupled to the mechanical structure 2700 in an associated manner. For example, a linkage (and any linkage described herein) may include four links within or coupled to the mechanical structure 2700. The linkage includes a first link coupled to the shaft 2410 and a second link including or coupled to a spring, as described in more detail below with reference to linkage 4850 or 5850. The four links of the linkage maintain connector tension within the medical device (e.g., connectors for moving end effectors and wrist assemblies, described in more detail below) and provide linear movement of the shaft 2410 when an axial force is applied at the distal end of the medical device 2400. The linkage also constrains movement on the z-axis and isolates forces on the z-axis. As described below, a force sensor unit 2800 measures the z-axis movement of the shaft, converting it from a position measurement to a force measurement. For a given axial force F z The travel of shaft 2410 depends in part on the stiffness of the spring included in the linkage. Therefore, the force sensor unit 2800, including the linkage and any spring therein, is calibrated to provide the desired range of motion of shaft 2410 within the expected range of axial force.

[0075] As described herein, the coil assembly (not shown) of the force sensor unit 2800 measures the displacement of the shaft along the z-axis, which is then converted into a force measurement. The coil assembly may include two induction coils, each wound around a cylinder formed of a non-conductive material, such as, for example, PEEK. The two coils may be positioned side-by-side with each other and coupled to or within the mechanical structure 2700. A rod movable within the coils and coupled to the shaft 2410 of the medical device 2400 resides within each coil. For example, the rod may include a core having a magnet coupled to the core that moves with the rod within the respective coil. The core may be, for example, a glass core, a stainless steel core, or a core formed of another suitable material. The magnet, and any magnet described herein, may be, for example, a ferrite bead, an EMI suppression bead, a nickel-zinc bead, or any other suitable material. Therefore, it should be understood that the term "magnet" as used herein may refer to any component or material of the core, or coupled to the core, which may be used to provide a signal indicating the position of the core within the corresponding coil as the rod and core move within the coils. The rod is operatively coupled to the shaft 2410 such that when the shaft 2410 moves axially due to a force applied to the distal end of the medical device 2400, the rod moves together with the shaft 2410 and within the coils. As the rod moves within the induction coils, the inductance of each coil changes, which can be used to measure changes in the position of the instrument axis. As described above, changes in the position of the shaft 2410 can be converted into z-axis force measurements.

[0076] During use of the medical device 2400, when a force is applied to shaft 2410 in the z-direction, shaft 2410 will travel along the z-axis, which in turn causes the rod to travel along the z-axis. As the rod moves within a corresponding coil, each coil generates a signal associated with the position of the rod's magnet within that coil. A microprocessor receives the signals from the coils. For example, in some embodiments, each coil generates a signal associated with a linear displacement of the shaft along its central axis (e.g., along the z-axis). In some embodiments, the signals from the coils may include a first signal from a first coil having a first frequency and a second signal from a second coil having a second frequency. The microprocessor is configured to execute instructions to determine a measure of the force on the shaft along its central axis based on the first and second frequencies. Further details regarding the operation and interaction of the microprocessor will be referenced below. Figure 33 Describe it.

[0077] Figure 6AThis is a schematic diagram of another embodiment of a medical device having a force sensor unit that uses an induction coil as a force sensor. In some embodiments, the medical device 3400 or any component thereof may optionally be part of a surgical system for performing surgical procedures, and may include a manipulator unit, a series of kinematic linkages, a series of cannulas, or the like. The medical device 3400 (and any instruments described herein) can be used in any suitable surgical system, such as the MIRS system 1000 shown and described above. The medical device 3400 includes a mechanical structure 3700, a force sensor unit 3800, a shaft 3410 coupled to the mechanical structure 3700 and the force sensor unit 3800, and an end effector 3460 coupled to a distal portion of the medical device 3400. As described above, the end effector 3460 may include, for example, an articulated clamp or another suitable surgical tool and may be coupled to a link (not shown). In some embodiments, the link may be included within a wrist assembly having a plurality of articulated links.

[0078] Shaft 3410 defines a central axis C3 and includes a distal portion coupled to end effector 3460. In some embodiments, the distal portion of shaft 3410 is coupled to the end effector via a beam (e.g., similar to beam 2810) that can be used to measure lateral forces applied thereto. In other embodiments, shaft 3410 may be directly coupled to a link, a wrist joint (not shown), or end effector 3460. Shaft 3410 is movably coupled to mechanism 3700 at its proximal portion. Thus, an axial force applied to end effector 3460 will produce movement of shaft 3410 relative to mechanism 3700, which can be measured using force sensor unit 3800, as described herein. Mechanism 3700 may include components configured to move one or more parts of a surgical instrument, such as, for example, end effector 3460. Mechanism 3700 may be similar to mechanism 5700, which is described in more detail below with reference to medical device 5400.

[0079] The force sensor unit 3800 includes a coil assembly 3815, which includes a first coil 3812, a second coil 3814, a first rod 3816, a second rod 3818, a first magnet 3831, a second magnet 3833, and a mounting bracket 3837. The first coil 3812 and the second coil 3814 are each an inductive coil wound around a cylinder formed of a non-conductive material such as PEEK. The first coil 3812 and the second coil 3814 are each secured to the mounting bracket 3837 (which is coupled to or included within the mechanical structure 3700) and positioned side-by-side with respect to each other. Similarly, the first coil 3812 and the second coil 3814 are mounted within the mechanical structure 3700 in a non-coaxial arrangement. The coils 3812 and 3814 extend a distance or height H from the mounting bracket, such as... Figure 6A As shown. The non-coaxial arrangement of the coils reduces the overall height of the force sensor unit 3800, thereby saving space within the mechanical structure 3700. Although the two coils are shown extending the same distance from the mounting bracket 3837, in other embodiments, the height of the first coil 3812 may differ from the height of the second coil 3814.

[0080] A first rod 3816 is coupled to shaft 3410 and movably disposed within a first coil 3812. Specifically, the first rod 3816 defines a central axis C1, and the first rod 3816 (and the first magnet 3831) translates within the first coil 3812 along the central axis C1. A second rod 3818 is coupled to shaft 3410 and movably disposed within a second coil 3814. The second rod 3818 defines a central axis C2, and the second rod 3818 (and the second magnet 3833) translates within the second coil 3814 along this central axis C2. As shown, the central axis C2 of the second rod 3818 is not coaxial with the central axis C1 of the first rod 3816. The first rod 3816 and the second rod 3818 may each include a core formed of, for example, glass or stainless steel, to which the magnet is coupled. As described above with respect to the previous embodiment, the core may be, for example, a glass core, a stainless steel core, or a core formed of another suitable material. Magnets 3831 and 3833 may be, for example, ferrite beads, EMI suppression beads, nickel-zinc beads, or any other suitable material or component or material of the core or coupled to the core, which may be used to provide a signal indicating the position of the core within the respective coils 3812 and 3814 as the bars 3816 and 3818 and the core move within their respective coils. More specifically, the first magnet 3831 is coupled to the first bar 3816 and the second magnet is coupled to the second bar 3818 such that the first magnet 3831 moves with the first bar 3816 and the second magnet 3833 moves with the second bar 3818. As described above, the first rod 3816 and the second rod 3818 are coupled to the shaft 3410 such that when the shaft 3410 moves axially due to a force applied to the distal end of the medical device 3400 (e.g., at the end effector 3460), the rods 3816 and 3818 move together with the shaft 3410 within coils 3812 and 3814, respectively. As the rods 3816 and 3818, along with the magnets 3831 and 3833, move within the induction coils 3812 and 3814, the inductance of each coil changes, which can be used to measure the positional change of the shaft 3410. This positional change of the shaft 3410 can be converted into a z-axis force measurement.

[0081] As shown in the figure, a first rod 3816 (with a magnet 3831 coupled thereto) is substantially centered within a first coil 3812. Therefore, the central axis C1 of the first rod 3816 is coaxial with the central axis of the first coil 3812. The clearance between the outer surface of the first rod 3816 and the inner surface of the first coil 3812 can be any suitable value to allow for tolerance errors in rod placement and reduce the possibility of contact between the first rod 3816 and the first coil 3812. This is desirable because internal friction between the rod and the coil can lead to erroneous force readings on the z-axis. Similarly, a second rod 3818 (with a magnet 3833 coupled thereto) is substantially centered within a second coil 3814. Therefore, the central axis C2 of the second rod 3818 is coaxial with the central axis of the second coil 3814. As described with respect to the first coil 3812 and the first rod 3814, the clearance between the outer surface of the second rod 3818 and the inner surface of the second coil 3814 can be any suitable value. In some embodiments, the gap between each pair of coils / bars may be approximately 1.3 mm (0.050 inches).

[0082] In some embodiments, the central axis C3 of shaft 3410 is located between the central axis C1 of the first rod 3816 and the central axis C2 of the second rod 3818, such as Figure 6A As shown. In some embodiments, the central axis C3 of shaft 3410 is parallel to the central axes C1 and C2 of the first rod 3816 and the second rod 3816, respectively. In some embodiments, the central axis C3 of shaft 3410 is located between the central axis C2 of the first rod 3816 and the central axis C2 of the second rod 3818.

[0083] In some embodiments, the medical device 3400 may further include a linkage device and a microprocessor as described above for the medical device 2400 (each not in [the following text is missing from the original]). Figure 6A (As shown in the diagram). The linkage can be any suitable mechanism such that the amount of shaft movement can be correlated with the applied axial force F. zThe shaft 3410 is movably coupled to the mechanical structure 3700 in a mutually correlated manner. For example, a linkage (and any linkage described herein) may include four links within or coupled to the mechanical structure 3700. The linkage may include a first link coupled to the shaft 3410 and a second link including or coupled to a spring, as described in more detail below with reference to specific embodiments. The four links of the linkage maintain connector tension within the medical device 3400, and the linkage provides linear movement of the shaft 3410 when an axial force is applied at the distal end of the medical device 3400. The linkage may also constrain movement along the z-axis (minor lateral movement of the shaft at small z-axis displacements involved in z-axis force sensing is negligible) and isolate forces along the z-axis. As described above, the force sensor unit 3800 measures the change in inductance within the coil caused by z-axis movement of the shaft (i.e., along the central axis C3 of the shaft 3410), which is converted from position to force.

[0084] For a given axial force F z The travel of shaft 3410 depends in part on the stiffness of the spring included in the linkage. Therefore, as described above with respect to the previous embodiment, the force sensor unit 3800, including the linkage and any spring therein, is calibrated to provide the desired range of motion of shaft 3410 within the expected range of axial force. The spring can convert the applied axial force into a displacement signal. As mentioned above, the link between the spring and coil assembly 3815 can be grounded to the same rigid component of the mechanical structure 3700, thereby avoiding erroneous force signals due to deflection differences between different grounded components.

[0085] During use of the medical device 3400, when a force is applied to shaft 3410 along the z-axis, shaft 3410 will travel along the z-axis, which in turn causes rods 3816 and 3818 to translate along the z-axis (along their respective central axes; similarly, any lateral movement at the axial displacement associated with z-axis force sensing is negligible). As rods 3816 and 3818 move within their respective coils (3812 and 3814), each of coils 3812 and 3816 generates a signal associated with the position of magnets 3831 and 3833 within their respective coils 3812 and 3814. Thus, each coil generates a signal associated with a linear displacement of the shaft along the central axis C3 of shaft 3410 (i.e., along the z-axis). A microprocessor (not shown) receives these signals from coils 3812 and 3814. In some embodiments, the signals from the coils may include a first signal with a first frequency from a first coil and a second signal with a second frequency from a second coil. The microprocessor is configured to execute instructions to determine the magnitude of the force on the axis 3410 along the central axis C3 of the axis 3410 based on a first frequency and a second frequency.

[0086] In some embodiments, the first coil 3812 and the second coil 3814 have identical configurations (e.g., coil diameter, number of windings, wire type, coil height, etc.). The side-by-side positioning and identical configuration of coils 3812 and 3814 provide a fully redundant force sensor, which can also be mounted within the confined space of the mechanical structure 3700. Parameters contributing to the ability to achieve a redundant force sensor configuration are the coil length (or height), width, and coil wire thickness, as well as the rod size, thereby enabling optimal coil size and increasing the linear range of the rod within the coil. Coils 3812 and 3814, having identical dimensions (e.g., height, wire diameter, width, material), are wound separately and coupled to the coil mounting bracket 3837, thereby positioning them at the same height H within the medical device 3400. In this way, each coil 3812 and 3814 provides a separate signal that can be simultaneously tracked and compared. Because coils 3812 and 3814 have identical dimensional and material parameters, they can have similar temperature responses to their environment.

[0087] In addition to providing full redundancy, the coaxial arrangement of the coils allows for improved centering of the bar within the coils. Therefore, the force sensor unit 3800 can linearly measure force over the desired (increased) stroke range of the bars 3816 and 3818. Including a higher linear measurement range allows for the inclusion of a linkage spring (not shown) with lower stiffness, which in turn allows the shaft 3410 to move a greater distance when an axial force is applied to the end effector 3460. In this way, the force sensor unit 3800 provides a high dynamic range (i.e., the ability to accurately measure the displacement of the shaft 3410 and therefore accurately measure the axial force over a wide range of values). Besides providing a longer linear stroke range for the bars, positioning the two coils 3812 and 3814 in an adjacent configuration allows for a reduction in the height H of the coils 3812 and 3814 while still maintaining the desired inductance (which can be, for example, in the range of 0-2 μH).

[0088] In some embodiments, the force sensor unit 3800 can linearly measure the displacement of the shaft 3410 within, for example, ±2 mm (0.080 inches). The displacement range of the shaft 3410 can vary, for example, based on factors such as a specific configuration, the stiffness of the shaft 3410, etc. Similarly, in some embodiments, the force sensor unit 3800 can generate a linear relationship between the coil inductance and the movement of the rods 3816 and 3818 within the coils 3812 and 3814 within a range of ±2 mm (0.080 inches). This is achieved in part by coupling the rods 3816 and 3818 within the coils 3812 and 3814, respectively, such that the gap between the outer surfaces of the rods 3816 and 3818 and the inner surfaces of the coils 3812 and 3814 is approximately 1.3 mm (0.050 inches), as described above. This linearity is as follows: Figure 6B As shown, this is a graph illustrating the coil inductance and the corresponding rod (i.e., ferrite bead) movement along the z-axis. The coil and rod configuration optimizes the coil inductance to linearity, with a rod travel of ±2 mm (0.080 inches), as... Figure 6B The graph is shown. Linearity indicates an error of less than 1%. This longer stroke range allows for the use of less stiff springs in four-bar linkage mechanisms, which improves system stability and dynamic range (as described above). This configuration is also more tolerant of rod displacement due to thermal expansion, vibration, and impact.

[0089] Figure 6CThis is a schematic diagram of another embodiment of a medical device having a force sensor unit 4800, which uses two coaxially arranged induction coils to measure movement of shaft 4410, thereby acting as a force sensor. In some embodiments, the medical device 4400 or any component thereof may optionally be part of a surgical system performing surgical procedures, and it may include a manipulator unit, a series of kinematic linkages, a series of cannulas, or the like. The medical device 4400 (and any instruments described herein) can be used in any suitable surgical system, such as the MIRS system 1000 shown and described above. The medical device 4400 includes a mechanical structure 4700, a force sensor unit 4800, a shaft 4410 coupled to the mechanical structure 4700 and the force sensor unit 4800, and an end effector 4460 coupled to the distal portion of the medical device 4400. As described above, the end effector 4460 may include, for example, a hinged clamp or another suitable surgical tool and may be coupled to a link (not shown). In some embodiments, the linkage may be included within a wrist assembly having a plurality of articulated linkages. Shaft 4410 may be coupled at its proximal portion to a mechanical structure configured to move one or more components of a surgical instrument, such as an end effector 4460. The mechanical structure may be similar to mechanical structure 5700, which is described in more detail below with reference to medical device 5400.

[0090] The force sensor unit 4800 includes a coil assembly 4815, a linkage device 4850, and a microprocessor 4852. The coil assembly 4815 includes a first coil 4812, a second coil 4814, a first rod 4816, a second rod 4818, a first magnet 4831, a second magnet 4833, and a mounting bracket 4837. The first coil 4812 and the second coil 4814 are each induction coils wound around a cylinder formed of a non-conductive material (such as PEEK), and they are positioned side-by-side (e.g., ...). Figure 6C (As shown) and coupled to a mechanical structure, or coupled within a mechanical structure in a non-coaxial arrangement. The non-coaxial arrangement of the coils reduces the overall height of the force sensor unit 4800, thereby saving space within the mechanical structure 4700. Although the two coils are shown extending the same distance from the mounting bracket 4837, in other embodiments, the height of the first coil 4812 may differ from the height of the second coil 4814.

[0091] A first rod 4816 is coupled to shaft 4410 and movably disposed within a first coil 4812. Specifically, the first rod 4816 defines a central axis C1, and the first rod 4816 (and the first magnet 4831) translates within the first coil 4812 along the central axis C1. A second rod 4818 is coupled to shaft 4410 and movably disposed within a second coil 4814. The second rod 4818 defines a central axis C2, and the second rod 4818 (and the second magnet 4833) translates within the second coil 4814 along the central axis C2. As shown, the central axis C2 of the second rod 4818 is not coaxial with the central axis C1 of the first rod 4816. The first rod 4816 includes a support portion 4817, and the second rod 4818 includes a support portion 4819, each rod being coupled to shaft 4410. The first rod 4816 and the second rod 4818 may each include a core having a magnet coupled thereto. As described above with respect to the previous embodiments, the core may be, for example, a glass core, a stainless steel core, or a core formed of another suitable material. Magnets 4831 and 4833 may be, for example, ferrite beads, EMI suppression beads, nickel-zinc beads, or any other suitable material or component or material coupled to the core that may be used to provide signals indicating the position of the core within the respective coils 4812 and 4814 as the core moves within the respective coils 4816 and 4818. A first magnet 4831 is coupled to a first rod 4816 and a second magnet 4833 is coupled to a second rod 4818, such that the first magnet 4831 moves with the first rod 4816 and the second magnet 4833 moves with the second rod 4818. As described above, the first rod 4816 and the second rod 4818 are coupled to the shaft 4410 such that when the shaft 4410 moves axially due to a force applied to the distal end of the medical device 4400 (e.g., at the end effector 4460), the rods 4816 and 4818 move together with the shaft 4410 and within coils 4812 and 4814, respectively. As the rods 4816 and 4818, along with the magnets 4831 and 4833, move within the induction coils 4812 and 4814, the inductance of each coil changes, which can be used to measure the positional change of the shaft 4410. This positional change of the shaft 4410 can be converted into a z-axis force measurement.

[0092] The first rod 4816 (with a magnet 4831 coupled thereto) is substantially centered within the first coil 4812. Therefore, the central axis C1 of the first rod 4816 is coaxial with the central axis of the first coil 4812. The gap between the outer surface of the first rod 4816 and the inner surface of the first coil 4812 can be, for example, approximately 1.3 mm (0.050 inches). Similarly, the second rod 4818 (with a magnet 4833 coupled thereto) is substantially centered within the second coil 4814. Therefore, the central axis C2 of the second rod 4818 is coaxial with the central axis of the second coil 4814. The gap between the outer surface of the second rod 4818 and the inner surface of the second coil 4814 can be, for example, approximately 1.3 mm (0.050 inches). As described above, this gap allows for tolerances in rod placement and reduces friction. This is desirable because internal friction between the rod and the coil can lead to incorrect force readings on the z-axis.

[0093] The first coil 4812 and the second coil 4814 are each securely mounted to a mounting bracket 4837 and positioned side-by-side with each other. The mounting bracket 4837 is coupled to or contained within the mechanical structure 4700. In some embodiments, the central axis C3 of the shaft 4410 is between the central axis C1 of the first rod 4816 and the central axis C2 of the second rod 4818, as shown in the figure. Figure 6C As shown. In some embodiments, the central axis C3 of shaft 4410 is parallel to the central axes C1 and C2 of the first rod 4816 and the second rod 4816, respectively. In some embodiments, the central axis C3 of shaft 4410 is centered between the central axis C2 of the first rod 4816 and the central axis C2 of the second rod 4818.

[0094] Shaft 4410 is coupled to mechanical structure 4700 via linkage 4850, such that the amount of travel of shaft 4410 relative to mechanical structure 4700 can be correlated with the magnitude of the axial force applied to end effector 4460. In this way, measuring the distance traveled by shaft 4410 relative to mechanical structure 4700 can be used to determine the axial force. As described herein, linkage 4850 isolates the axial movement of shaft 4410 (i.e., constrains shaft movement such that the measured movement is caused only by axial force, and not by lateral forces along the X and Y axes), limits frictional forces opposite to the movement of shaft 4410, and provides a suitable structure for the coaxially arranged coils as described above. As shown, linkage 4850 includes four links coupled together or together to mechanical structure 4700 within mechanical structure 4700. More specifically, the linkage 4850 includes a first link 4821 coupled to the shaft 4410 and the coil assembly 4815, and a second link 4827 coupled to the first link 4821 and coupled to the support 4841. The second link 4827 includes (or is coupled to) a spring element 4829, which is coupled to or supported by the support 4841, such as... Figure 6B As shown. The linkage 4850 also includes a third link 4825 coupled to the first link 4821 and a fourth link 4823 coupled to the second and third links 4827. The fourth link 4823 is stationary and acts as a local mechanical ground for the other three links, which move when the shaft 4410 moves along its axis C3. The four links of the linkage 4850 can maintain connector tension within the medical device 4400 and provide linear movement of the shaft 4410 when an axial force is applied at the distal end of the medical device 4400. The linkage 4850 can also constrain movement on the z-axis and isolate forces on the z-axis. As described above, the force sensor unit 4800 measures the change in inductance in the coil caused by the z-axis movement of the shaft (i.e., along the central axis C3 of the shaft 3410), which is converted from a position value into the magnitude of the axial force.

[0095] Support portions 4817 and 4819 of rods 4816 and 4818 each extend through an opening in the mounting bracket 4837 and are coupled to the first link 4821, thus coupling them to the shaft 4410. For example, in some embodiments, support portions 4817 and 4819 may be press-fitted to the first link 4821. In some embodiments, such as Figure 6C As shown, support portions 4817 and 4819 (e.g., press-fit or by another suitable coupling method) are coupled to bracket 4839, which is coupled to first link 4821.

[0096] The amount of travel of shaft 4410 in response to axial force depends in part on the stiffness of spring 4829 of second link 4827. For example, if spring 4829 is very stiff, shaft 4410 will only move a small distance when an axial force is applied to end effector 4460. Conversely, if spring 4829 is less stiff, the same axial force will produce a larger movement of shaft 4410. Therefore, spring 4829 can be selected to have a desired stiffness such that the total travel of shaft 4410 within the expected range of the applied axial force will be within the dynamic range of force sensor unit 4800.

[0097] As described above, in some embodiments, the second link 4827 (with spring 4829) and the coil assembly 4815 can be grounded to the same rigid component of the mechanical structure 4700. This arrangement reduces the likelihood of erroneous force signals due to deflection differences in the components of the force sensor unit 4800, which could be caused by different grounding of the components.

[0098] During use of the medical device 4400, when a force is applied to shaft 4410 along the z-axis, shaft 4410 will travel along the z-axis, which in turn causes rods 4816 and 4818 to translate along the z-axis (along their respective central axes). As rods 4816 and 4818 (and magnets 4831 and 4833) move within their respective coils (4812 and 4814), each of coils 4812 and 4816 generates a signal associated with the position of magnets 4831 and 4833 within their respective coils 4812 and 4814. Microprocessor 4852 receives these signals from coils 4812 and 4814. As described above, in some embodiments, each of coils 4812 and 4814 generates a signal associated with a linear displacement of the shaft along the central axis C3 of shaft 4410 (e.g., along the z-axis). In some embodiments, the signal from the coil may include a first signal having a first frequency from the first coil 4812 and a second signal having a second frequency from the second coil 4814. The microprocessor 4852 is configured to execute instructions to determine the magnitude of the force on the shaft 4410 along the central axis C3 of the shaft 4410 based on the first and second frequencies.

[0099] As described above, the side-by-side positioning and identical configuration of coils 4812 and 4814 (e.g., coil diameter, number of windings, wire type, coil height, etc.) provide a fully redundant force sensor that can also be fitted within the confined space of mechanical structure 4700 and can linearly measure force within a suitable stroke range of bars 4816 and 4818. In some embodiments, the linear range is within ±2 mm (0.080 inches) inside coils 4812 and 4814. This is achieved in part by coupling bars 4816 and 4818, respectively, within coils 4812 and 4814, such that the clearance gap between the outer surfaces of bars 4816 and 4818 and the inner surfaces of coils 4812 and 4814 has an appropriate amount. In some embodiments, the clearance gap can be approximately 1.33 mm (0.050 inches) as described above. Other parameters that contribute to the ability to achieve a redundant force sensor configuration are the coil length (or height), width, and thickness of the coil wires, as well as the dimensions of the bars, allowing for optimal coil size and increasing the linear range of the bars within the coils. In addition to providing a longer linear travel range for the rod, positioning the two coils 4812 and 4814 in an adjacent configuration allows for a reduction in the height H of the coils 4812 and 4814 and maintains the inductance within the 0-2 μH range. The coils 4812 and 4814 have identical dimensions (e.g., height, wire diameter, width, material) and are wound separately and coupled to a coil mounting bracket, thereby positioning them at the same height H within the medical device 4400. In this way, each coil 4812 and 4814 provides a separate signal that can be tracked and compared simultaneously. Because the coils 4812 and 4814 have the same dimensions and material parameters, they can have similar temperature responses to their environment. Therefore, by determining displacement based on the two signals, the effects of temperature can be subtracted.

[0100] Figures 7A-32These are various views of a medical device 5400 and its components according to one embodiment. In some embodiments, the medical device 5400 or any component thereof may optionally be part of a surgical system for performing surgical procedures, and may include a manipulator unit, a series of kinematic linkages, a series of cannulas, or the like. The medical device 5400 (and any instruments described herein) can be used in any suitable surgical system, such as the MIRS system 1000 shown and described above. The medical device 5400 includes a mechanical structure 5700 located at the proximal portion of the medical device 5400, an outer shaft 5910, a shaft 5410 (serving as an inner shaft in this embodiment), a force sensor unit 5800, and a distal mechanism including a wrist assembly 5500 and an end effector 5460. Although not shown, the instrument 5400 may also include one or more connectors that couple the mechanical structure 5700 to the wrist assembly 5500 and the end effector 5460, and act as tensioning members to actuate the end effector 5460. In some embodiments, the connector may be a cable, strap, or the like. The device 5400 is configured such that a selective movement of the connector produces a wrist assembly 5500 about a first rotation axis A1 (see [reference]). Figure 8 (which serves as the pitch axis; the term pitch is arbitrary) rotation (i.e., pitch rotation), end effector 5460 about the second rotation axis A2 (see Figure 8 (This serves as the yaw axis; the term yaw is arbitrary) a yaw rotation, a cutting rotation of the tool component of the end effector 5460 about the second axis of rotation A2, or any combination of these movements. Changes in the pitch or yaw of the instrument 5400 can be performed by manipulating the connector in a manner similar to that described, for example, in U.S. Patent No. US8,821,480B2 entitled “Four-Cable Wrist with Solid Surface Cable Channels” (filed July 16, 2008), which is incorporated herein by reference in its entirety. Therefore, the specific movements of each connector to achieve the desired motion are not described below.

[0101] Shaft 5410 includes a proximal end 5411 coupled to mechanical structure 5700 and a distal end 5412 coupled to beam 5810 via anchor 5925 (see [link]). Figure 8Beam 5810 may include or be coupled to one or more strain sensors (not shown) to measure forces applied to surgical instruments in the x and y directions during a surgical procedure. Therefore, beam 5810 may be part of a force sensor unit similar to those shown and described in co-pending U.S. Provisional Patent Application No. 63 / 026,321 (filed May 18, 2020) entitled “Devices and Methods for Stress / Strain Isolation on a Force Sensor Unit,” the disclosure of which is incorporated herein by reference in its entirety. Although beam 5810 with xy sensors is shown and described in this embodiment, beam 5810 and xy sensors may not be included in other embodiments. The proximal end of shaft 5410 allows shaft 5410 to travel along its central axis C3 ( Figure 8 (As shown) Coupled to the mechanical structure 5700 in a manner that allows it to move relative to the mechanical structure 5700. More specifically, in this embodiment, the shaft 5410 extends through an opening 5764 in the base 5770 of the mechanical structure 5700 (see... Figure 9 And coupled to a first link 5821 of a linkage 5850 that allows shaft 5410 to translate and rotate along the z-axis, as described in more detail below. Allowing shaft 5410 to float relative to mechanical structure 5700 in the z-direction (i.e., to remain in an energy-neutral but displaceable position) facilitates the measurement of forces along the z-axis, as described herein. Shaft 5410 also defines a lumen (not shown) and / or multiple channels through which connectors and other components (e.g., wires, ground wires, or the like) can be routed from mechanical structure 5700 to wrist assembly 5500. Anchors 5925 can be at least partially received within the lumen of shaft 5410 and can be securely coupled to shaft 5410 by adhesive bonding, welding, or any other permanent coupling mechanism (i.e., a coupling mechanism not intended to be removed during normal use).

[0102] The outer shaft 5910 can be any suitable elongated shaft, which can be disposed on the shaft 5410 and includes a distal end 5912 and a proximal end 5911 that can be coupled to the mechanical structure 5700. The outer shaft 5910 defines a lumen between the proximal end 5911 and the distal end 5912. The shaft 5410 extends within the lumen of the outer shaft 5910 and can be movable relative to the outer shaft 5910. For example, the shaft 5410 can be rotated relative to the outer shaft 5910 and / or can be longitudinally translated in a direction parallel to the central axis C3 of the shaft 5410 (i.e., the z-direction). In this embodiment, the proximal end 5911 of the outer shaft 5910 is coupled to a locking handle 5919, which is fixedly coupled to the mechanical structure 5700, such as... Figure 7BAs shown. The locking handle 5919 can be used to move the outer shaft 5410 relative to the axis 5410 and lock the outer shaft 5910 in a position relative to the axis 5410 along the z-axis. In this way, the outer shaft 5910 can retract (i.e., move proximally) relative to the axis 5410 to expose the beam 5810 for cleaning the beam 5810 or any sensors coupled thereto. In some embodiments, the locking handle 5919 is capable of being constructed and functioning in the same or similar manner as the outer shaft mounting tube assembly 970 shown and described in co-pending U.S. Provisional Patent Application No. 62 / 916,716 (filed October 17, 2019) entitled “Surgical Tool with Nested Shafts,” the disclosure of which is incorporated herein by reference in its entirety. In other embodiments, the outer shaft 5910 or a portion thereof can be movable relative to the mechanical structure 5700 (e.g., the outer shaft 5910 can be a telescopic shaft).

[0103] refer to Figure 8 The wrist assembly 5500 includes a proximal first link 5510 and a distal second link 5610. The first link 5510 includes a distal portion coupled at a joint to the proximal portion of the second link 5610, thereby allowing the second link 5610 to rotate relative to the first link 5510 about a first rotation axis A1 (which serves as a pitch axis; the term pitch is arbitrary). The proximal first link 5510 includes a proximal portion coupled to a beam 5810, as described in more detail herein.

[0104] The distal end of the second distal link 5610 is coupled to the end effector 5460, thereby allowing the end effector 5460 to rotate about the second axis of rotation A2 (see...). Figure 8(It rotates as a yaw axis). The end effector 5460 may include at least one tool member 5462 having a contact portion 5464 configured to engage or manipulate target tissue during a surgical procedure. For example, in some embodiments, the contact portion 5464 may include an engagement surface as a gripper, cutter, tissue manipulator, or the like. In other embodiments, the contact portion 5464 may be an energized tool member for cauterization or electrosurgical procedures. The end effector 5460 is operatively coupled to a mechanical structure 5700 such that the tool member 5462 rotates about a first rotation axis A1 relative to the axis 5410. In this way, the contact portion 5464 of the tool member 5462 can be actuated to engage or manipulate target tissue during a surgical procedure. The tool member 5462 (or any tool member described herein) may be any suitable medical tool member. Furthermore, although only one tool component 5462 is identified, as shown in the figure, the instrument 5400 may include two tool components that cooperate to perform a clamping or cutting function. In other embodiments, the end effector may include more than two tool components.

[0105] Mechanical structure 5700 includes components for generating movement of connectors (not shown) to produce desired movement (pitch, yaw, or clamping) at wrist assembly 5500. Specifically, mechanical structure 5700 includes components and controls to move some connectors in a proximal direction (i.e., pull in some connectors) while allowing other connectors to move distally over the same length (i.e., release; extend). In this way, mechanical structure 5700 can maintain desired tension within the connectors, and in some embodiments, can ensure that the length of the connectors is maintained (i.e., equal movement) throughout the entire range of motion of wrist assembly 5500. However, in other embodiments, it is not necessary to maintain the length of the connectors.

[0106] In some embodiments, mechanical structure 5700 may include one or more mechanisms that generate translational (linear motion) of a portion of the connector. Such mechanisms may include, for example, a universal joint, a lever, or any other suitable mechanism that directly pulls (or releases) the end portion of any connector. For example, in some embodiments, mechanical structure 5700 may include any mechanical structure (referred to as a back-end assembly or actuator) or component described in U.S. Patent Application Publication No. 20157 / 0047454A1 (filed August 15, 2014) entitled “Lever Actuated Gimbal Plate” or U.S. Patent No. US6,817,974B2 (filed June 28, 2001) entitled “Surgical Tool Having Positively Positionable Tendon-Actuated Multi-Disk Wrist Joint”, each of which is incorporated herein by reference in its entirety.

[0107] like Figures 9-12 As shown, the mechanical structure 5700 includes three winches 5720, 5730, and 5740 (which serve as actuator inputs) and a roller driver 5750, each serving as an operation input. The winches 5720, 5730, and 5740 are motor-driven rollers that rotate (wrap around) a portion of a connector (not shown) to produce desired connector movement, and thus desired movement of the wrist assembly 5500 and the end effector 5460. As described below, the roller driver 5750 is a motor-driven member that produces rotation (referred to as “rolling”) of the shaft 5410. In some embodiments, the mechanical structure 5700 may be configured to be identical or similar to the mechanical structure (referred to as the end-effector or actuator) described in U.S. Patent No. 9,204,923B2 (filed July 16, 2008) entitled “Medical Instrument Electronically Energized Using Drive Cables,” the entire contents of which are incorporated herein by reference. Mechanical structure 5700 also includes a device support structure, which includes a base 5770, a top plate 5762, a circuit board 5765, and a common-mode choke 5763 (see below). Figure 33 (Discussed in more detail). In other embodiments, various support structures may be optionally used, such as chassis, frames, beds, modular surrounding bodies of mechanical structures, and the like.

[0108] Mechanical structure 5700 surrounds (or is coupled to) force sensor unit 5800, which includes coil assembly 5815, linkage 5850 (which serves as a movable four-bar linkage), and microprocessor (see [link]). Figure 33(Example microprocessor in the example). The linkage 5850 includes four links coupled to the mechanical structure 5700. More specifically, as... Figure 13 and 14 In its best-presentation configuration, the linkage 5850 includes a first link 5821 coupled to shaft 5410 (which functions to support the shaft and allow it to roll; "roller"), coupled to the first link 5821 and coupled to support 5841 (see, for example...). Figure 15 The first link 5827. A bracket 5839 is coupled to one end of the first link 5821 and is used to couple the rod of the coil assembly 5815 to the first link 5821, as described in more detail below. The second link 5827 includes a spring element 5829, which is coupled to or supported by a support 5841, as... Figure 15 As shown. The linkage 5850 also includes a third link 5825 coupled to the first link 5821 and a fourth link 5823 coupled to the second link 5827 and the third link 5825. The fourth link 5823 is stationary and acts as a local mechanical ground for the other three links, which move when the shaft 5410 moves along its axis CA. The four links of the linkage 5850 can maintain connector tension within the medical device 5400 and provide linear movement of the shaft 5410 when an axial force is applied at the distal end of the medical device 5400. The linkage 5850 can also constrain movement on the z-axis and isolate forces on the z-axis.

[0109] Shaft 5410 is coupled to mechanical structure 5700 via linkage 5850, such that the amount of travel of shaft 5410 relative to mechanical structure 5700 can be correlated with the magnitude of the axial force applied to end effector 5460. In this way, measuring the distance traveled by shaft 5410 relative to mechanical structure 5700 can be used to determine the axial force applied to the distal end of shaft 5410 (e.g., at end effector 5460). As described herein, linkage 5850 isolates the axial movement of shaft 5410 (i.e., constrains shaft movement so that the measured movement is caused only by axial force, and not by lateral forces along the x and y axes), limits frictional forces opposite to the movement of shaft 5410, and provides a suitable structure for coaxially arranged coils, as described below.

[0110] More specifically, shaft 5410 drives receiver 5738 via roller (see example...) Figures 21-22A first link 5821 is coupled to the linkage 5850 such that when the shaft 5410 moves along the z-axis, the first link 5821 moves together with the shaft 5410 along the z-axis. In other words, the shaft 5410 is coupled to the first link 5821 in a manner that limits the movement of the shaft 5410 relative to the first link 5821 along the z-axis. However, the roller drive receiver 5738 allows the shaft 5410 to also rotate relative to the first link 5821 (e.g., when the shaft 5410 rotates about the z-axis, the first link 5821 does not rotate). The roller drive receiver 5738 can be actuated by a cable (belt, rope, or other suitable connector (not shown)) coupled to the roller drive 5750 and wound around a portion of the roller drive receiver 5738. This arrangement allows the shaft 5410 to move about the z-axis relative to the mechanical structure 5700 (which allows for the measurement of axial force) while also allowing the shaft 5410 to rotate about the z-axis.

[0111] The spring 5829 of the second link 5827 can be formed of a more flexible material than the rest of the second link 5827, thus producing a spring with the desired stiffness. The amount of travel of the shaft 5410 in the z-axis direction depends in part on the stiffness of the spring 5829 of the second link 5827. For example, if the spring 5829 is very stiff, the shaft 5410 will only move a short distance when an axial force is applied to the end effector 5460. Conversely, if the spring 5829 is less stiff, the same axial force will produce a larger movement of the shaft 5410. Therefore, the spring 5829 can be selected to have the desired stiffness such that the total travel of the shaft 5410 within the expected range of the axial force to be applied will be within the dynamic range of the force sensor unit 5800. Although the spring 5829 is shown as a leaf spring, in other embodiments, the linkage 5850 may include any suitable type of spring (e.g., a coil spring or a torsion spring).

[0112] Figure 18 The position of the second link 5827 is shown when the second link 5827 and the shaft 5410 are in a neutral position (e.g., unacted). During use of the medical device 5400, as the shaft moves along the z-axis, the first link 5821 will move with the shaft 5410, and the second link 5827, coupled to the first link 5821, will pivot about the pivot joint 5742. For example, Figure 19 The axis 5410 is shown to be translated proximally in the z-axis direction, and Figure 20 A shaft 5410 translated distally along the z-axis is shown (the first link 5821 has been removed for illustrative purposes). Figure 19 As shown, the second link 5827 is angled downwards, and the distance between the pivot joint 5742 and the reference line L is D1. Figure 19 In the construction (proximal movement of shaft 5410), shaft 5410 is subjected to a first force F1. For example... Figure 20 As shown, the second link 5827 is angled upwards, and the distance D2 between the pivot joint 5742 and the reference line L is less than the distance D1. In this... Figure 20 In the construction (distal movement of shaft 5410), the shaft is subjected to a second force F2, which is less than the first force F1. The magnitudes of the first force F1 and the second force F2 can be determined by measuring distances D1 and D2.

[0113] like Figures 26-29 As shown, the coil assembly 5815 includes a first coil 5812, a second coil 5814, a first rod 5816, a second rod 5818, a first magnet 5831, a second magnet 5833, and a mounting bracket 5837. The mounting bracket 5837 is secured within the mechanical structure 5700 and electrically coupled to the circuit board 5765 via wiring 5835. The first coil 5812 and the second coil 5814 are each mounted within the mounting bracket 5837 and positioned side-by-side with each other. Each of the first coil 5812 and the second coil 5814 is an induction coil and each is wound, for example, around a cylinder of a non-conductive material such as PEEK. The first coil 5812 and the second coil 5814 have the same characteristics, such as coil length, coil width, and coil wire thickness.

[0114] like Figure 25 As shown, the first rod 5816 is coupled to the bracket 5839 and is at least partially movably located within the first coil 5812. Similarly, the second rod 5818 is coupled to the bracket 5839 and is at least partially movably located within the second coil 5814. More specifically, as Figures 26 to 32 As shown, the first rod 5816 includes a support portion 5817 and the second rod 5818 includes a support portion 5819, each support portion being connected to the first link 5821 via a bracket 5839. For example, the support portions 5817 and 5819 of rods 5816 and 5818 each extend through an opening in the mounting bracket 5837 and are coupled to the bracket 5839, thereby coupling rods 5816 and 5818 to the first link 5821 and the shaft 5410. For example, in some embodiments, the support portions 5817 and 5819 may be press-fitted to the bracket 5839. In alternative embodiments, the support portions 5817 and 5819 may be coupled to the bracket 5839 by another suitable coupling method, such as adhesive or welding.

[0115] Therefore, since the first link 5821 is fixedly coupled to the shaft 5410 on the z-axis, both the first rod 5816 and the second rod 5818 are fixedly coupled to the shaft 5410 and can move together with the shaft 5410 and the first link 5821 along the z-axis. In some embodiments, the coil assembly 5815 is coupled to the mechanical structure 5700 such that the central axis C3 of the shaft 5410 is between the central axis C1 of the first rod 5816 and the central axis C2 of the second rod 5818, as shown in the figure. Figure 12 As shown. In some embodiments, the central axis C3 of shaft 5410 is parallel to the central axes C1 and C2 of the first rod 5816 and the second rod 5816, respectively. In some embodiments, the central axis C3 of shaft 5410 is located between the central axis C2 of the first rod 5816 and the central axis C2 of the second rod 5818.

[0116] like Figure 29 As shown, the first rod 5816 includes a core 5836, and the second rod 5818 includes a core 5838. A first magnet 5831 is coupled to the core 5836 of the first rod 5816, and a second magnet 5833 is coupled to the core 5838 of the second rod 5818, such that the first magnet 5831 moves together with the first rod 5816, and the second magnet 5833 moves together with the second rod 5818. For example, as described above, the first rod 5816 and the second rod 5818 are coupled to the shaft 5410, such that when the shaft 5410 moves axially due to a force applied to the distal end of the medical device 5400 (e.g., at the end effector 5460), the rods 5816 and 5818 move together with the shaft 5410 within coils 5812 and 5814, respectively. When bars 5816 and 5818 and magnets 5831 and 5833 move within induction coils 5812 and 5814, this movement causes a change in inductance at the coils, which can be used to measure the positional change of shaft 5410, which can be converted into a z-axis force measurement. As described above with respect to the previous embodiment, cores 5836 and 5838 can each be, for example, a glass core, a stainless steel core, or a core formed of another suitable material. Magnets 5831 and 5833 can each be, for example, a ferrite bead, an EMI suppression bead, a nickel-zinc bead, or any other suitable material or component or material that can be used to couple to the respective core as bars 5816 and 5818 and the core move within their respective coils 5812 and 5814.

[0117] The first rod 5816 (with magnet 5831) is substantially centered within the first coil 5812, with a gap G between the outer surface of the first rod 5816 and the inner surface of the first coil 5812 (see [link]). Figure 30(Bottom view of the coil assembly). Similarly, the second rod 5818 (with magnet 5833) is substantially centered within the second coil 5814, with a gap G between the outer surface of the second rod 5818 and the inner surface of the second coil 5814. In some embodiments, the gap G is approximately 1.33 mm (0.050 inches). As mentioned above, this gap allows for tolerances in the placement of the rod and reduces the possibility of frictional losses between the rod and the coil. This is desirable because internal friction between the rod and the coil can cause erroneous force readings in the z-axis direction.

[0118] During use of medical device 5400, when a force is applied along the z-direction to shaft 5410, shaft 5410 will travel along the z-axis, which in turn causes rods 5816 and 5818 to translate along the z-axis (along their respective central axes). As rods 5816 and 5818 (and magnets 5831 and 5833) move within corresponding coils 5812 and 5814, each of coils 5812 and 5816 generates a signal associated with the position of magnets 5831 and 5833 within the corresponding coils 5812 and 5814. A microprocessor (which may be similar to...) Figure 33 The microprocessor 6852 shown receives these signals from coils 5812 and 5814. As described above, each of coils 5812 and 5814 generates a separate signal associated with a linear displacement of shaft 5410 along its central axis C3 (e.g., along the z-axis). In some embodiments, the signals from the coils may include a first signal from the first coil 5812 having a first frequency and a second signal from the second coil 5814 having a second frequency. The microprocessor is configured to execute instructions to determine a measure of the force acting on shaft 5410 along its central axis C3 based on the first and second frequencies.

[0119] As described above, the force sensor unit 5800 measures the change in inductance within the coil caused by the z-axis movement of the shaft (i.e., along the central axis C3 of shaft 4410), converting the position measurement into a force measurement. As described above, the second link 5827 with spring 5829 and the coil assembly 5815 are mechanically grounded to the same rigid component of the mechanical structure 5700 (e.g., base 5770), thereby avoiding erroneous force signals due to deflection differences in different grounding components.

[0120] As described above, the side-by-side (non-coaxial) positioning and identical configuration of coils 5812 and 5814 provide a fully redundant force sensor capable of linearly measuring force within the appropriate stroke range of rods 5816 and 5818. In some embodiments, the linear range of this arrangement can be between ±2 mm (0.080 inches) within coils 5812 and 5814. In other embodiments, this range can vary depending on, for example, the geometry of the coils and other properties such as the materials of the wires and magnets. This is achieved in part by coupling rods 5816 and 5818 within coils 5812 and 5814, respectively, such that the gap G between the outer surfaces of rods 5816 and 5818 and the inner surfaces of coils 5812 and 5814 is an appropriate amount. In some embodiments, the gap G is approximately 1.33 mm (0.050 inches), as described above. Other parameters that contribute to achieving the capability of a redundant force sensor configuration are the coil length (height), coil width, and coil wire thickness, as well as the rod dimensions, thereby enabling optimal coil size and increasing the linear range of the rods within the coils. In addition to providing a longer linear stroke range for the rod, positioning the two coils 5812 and 5814 in an adjacent, side-by-side configuration allows the coils to be assembled within the constrained space of the mechanical structure 5700. For example, coils 5812 and 5814 may have a reduced height H (see...). Figure 26 The coils 5812 and 5814 have the same dimensions (e.g., height, wire diameter, width, material) and are wound separately. They are coupled to a mounting bracket 5837 such that they are positioned at the same height H relative to the mounting bracket 5837 within the medical device 4400. Each coil 5812 and 5814 provides a separate signal, which can be tracked and compared simultaneously. Because coils 5812 and 5814 have the same dimensions and material parameters, they have similar temperature responses to their environment. In some cases, significant differences in coil inductance can serve as a measure of drift.

[0121] Figure 33This is a block diagram as part of an embodiment of a force sensor unit 6800, which can be implemented to measure axial forces applied to an instrument axis (e.g., axis 5410). The force sensor unit 6800 can be implemented as a z-axis sensing force sensor unit (including force sensor unit 5800) as described above for any prior embodiment. As mentioned above, axial forces on the instrument axis cause axial movement of the instrument axis 6410, which can be detected by the force sensor unit 6800. The force sensor unit 6800 may include a coil assembly 6815 as described herein, comprising a pair of coils 6812 and 6814, with rods 6816 and 6818 movably positioned within coils 6812 and 6814, respectively. Rod 6816 may have a magnet 6831 coupled thereto, and rod 6818 may have a magnet 6833 coupled thereto.

[0122] Coil 6812 can be coupled to multi-channel frequency detection block 6865 via capacitor C. Capacitor C can form an inductor / capacitor (LC) circuit with coil 6812, with the inductance contribution based on the distance traveled by rod 6816 and magnet 6831 within coil 6812. Coil 6814 can be coupled to multi-channel frequency detection block 6865 via capacitor C. Capacitor C can form an LC circuit with coil 6814, with the inductance contribution based on the distance traveled by rod 6818 and magnet 6833 within coil 6814. The LC circuits associated with coils 6812 and 6814 can be implemented with different capacitors in embodiments that take this difference into account.

[0123] The multi-channel frequency detection block 6865 can be implemented as a precision dual-inductance sensor for measuring inductance. A capacitor C and coil 6812 form an LC circuit, which is input to the multi-channel frequency detection block 6865. The multi-channel frequency detection block 6865 can output a first signal associated with the frequency of this circuit, such as a frequency ratio with a known reference frequency. A capacitor C and coil 6814 form another LC circuit, which is input to the multi-channel frequency detection block 6865. The multi-channel frequency detection block 6865 can output a second signal associated with the frequency of this circuit, such as a frequency ratio with a known reference frequency. The multi-channel frequency detection block 6865 can output N digital signals to the microprocessor 6852. For two LC circuits, the multi-channel frequency detection block 6865 can output two digital signals to the microprocessor 6870.

[0124] The microprocessor 6852 may include or have access to an EEPROM 6872 or other storage device, which may include calibration values ​​for implementing magnets 6831 within coil 6812 and magnets 6833 within coil 6814. When measuring axial force on the instrument shaft, the calibration values ​​can be accessed to determine the distance moved by each magnet 6831 and 6833 based on frequencies received from the multi-channel frequency detection block 6865. Frequency differences can be stored in the EEPROM 6872 as inductance differences as a function of distance. This distance difference can be cross-correlated with a reference position and the inductance difference. A distance selected from the measured inductance difference can be used in conjunction with a spring constant stored in the EEPROM 6872, where the spring constant is a property of a spring (e.g., spring 5829 described above), through which the instrument shaft 6410 is coupled to a support structure on which a force sensor unit 6800 can be deployed.

[0125] The force sensor unit 6800 may include other optional components. For example, the microprocessor 6852 may include a Universal Asynchronous Receiver / Transmitter (UART) interface 6874 or other communication interfaces for transmitting (TX) digital output and receiving (RX) digital signals. The received signals can be used to update calibration values ​​in the EEPROM 6872 of the microprocessor 6852. A common-mode choke 6763 (e.g., common-mode choke 5863) can be used to reduce interference to other electronic circuit boards on which the force sensor unit 6800 is deployed. Optionally, the force sensor unit 6800 may include a magnetic structure 6862 between the common-mode choke 6763 and the microprocessor 6852. The magnetic structure 6862 can be inserted to help reduce electromagnetic interference (EMI) radiation. The magnetic structure 6862 can be implemented as a ferrite bead. As described above, other forms of magnetic materials can be implemented for the magnetic structure 6862.

[0126] Machine-readable storage devices may include any non-transitory mechanism for storing information in a machine-readable form, such as a computer or a microprocessor responsible for performing specific functions. For example, machine-readable storage devices may include read-only memory (ROM), random access memory (RAM), disk storage media, optical storage media, flash memory devices, and other storage devices and media. In various embodiments of the medical device with a force sensor unit described herein, the non-transitory machine-readable medium may include instructions that, when executed by one or more processors, cause the system to perform operations including, but not limited to, the following steps: (i) receiving a first signal generated by a first coil associated with the position of a first magnet relative to a first coil, and (ii) receiving a second signal coil generated by a second coil associated with the position of a second magnet relative to a second coil, wherein the first signal from the first coil and the second signal from the second coil are associated with a linear displacement of the shaft along the central axis of the shaft. The force sensor unit may include a microprocessor coupled to receive the first and second signals. In various embodiments, a non-transitory machine-readable medium may include instructions that, when executed by one or more processors, cause the system to perform operations including methods of performing functions associated with the various embodiments described herein.

[0127] While various embodiments have been described above, it should be understood that they are presented by way of example only and not limitation. Where the methods and / or diagrams above indicate specific events and / or process patterns occurring in a specific order, the order of specific events and / or operations may be modified. Although embodiments have been specifically shown and described, it should be understood that various changes in form and detail may be made.

[0128] For example, any instrument (and components thereof) described herein may optionally be part of a remote surgical system for performing minimally invasive surgical procedures, and may include a manipulator unit, a series of kinematic linkages, a series of cannulas, or the like. Therefore, any instrument described herein can be used with any suitable surgical system, such as the MIRS system 1000 shown and described above. Furthermore, any instrument shown and described herein can be used to manipulate target tissue during a surgical procedure. Such target tissue can be cancer cells, tumor cells, lesions, vascular occlusions, thrombosis, stones, uterine fibroids, bone metastases, adenomyosis, or any other body tissue. The examples of target tissues provided are not an exhaustive list. Additionally, target structures may include, for example, artificial materials (or non-tissues) within or associated with the body, such as scaffolds, portions of artificial tubes, fasteners within the body, or the like.

[0129] For example, any component of the surgical instruments described herein can be made of any material, such as medical-grade stainless steel, nickel alloys, titanium alloys, or the like. Furthermore, any linkage, tool component, beam, shaft, connector, cable, or other component described herein can be constructed from multiple parts that are later joined together. For example, in some embodiments, a linkage can be constructed by connecting separately constructed components together. However, in other embodiments, any linkage, tool, component, beam, shaft, connector, cable, or component described herein can be constructed as a single unit.

[0130] Although instruments are generally shown as having a tool component rotation axis (e.g., axis A2) perpendicular to the wrist component's rotation axis (e.g., axis A1), in other embodiments, any instrument described herein may include a tool component rotation axis that deviates from the wrist component's rotation axis at any suitable angle. While various embodiments have been described as having combinations of specific features and / or components, other embodiments may have any combination of features and / or components from any of the embodiments discussed above. Aspects have been described in the general context of medical devices, and more specifically surgical instruments, but the inventive aspects are not necessarily limited to use in medical devices.

Claims

1. A medical device comprising: A mechanical structure and a force sensor unit coupled to the mechanical structure; The force sensor unit includes a mounting bracket, a first rod, a second rod, a first magnet, a second magnet, a first coil coupled to the mounting bracket, and a second coil coupled to the mounting bracket. The first rod includes a distal portion and a proximal portion, and the central axis of the first rod is defined between the proximal portion and the distal portion of the first rod; The second rod includes a distal portion and a proximal portion, the central axis of the second rod is defined between the proximal portion and the distal portion of the second rod, and the central axis of the second rod is not coaxial with the central axis of the first rod; The first magnet is coupled to the first rod, and the second magnet is coupled to the second rod; and The first magnet translates within the first coil along the central axis of the first rod, and the second magnet translates within the second coil along the central axis of the second rod.

2. The medical device according to claim 1, wherein: The medical device also includes a shaft coupled to the mechanical structure; and The shaft is operatively coupled to the first bar and the second bar such that translational movement of the shaft relative to the mechanical structure causes the first bar to move along the central axis of the first bar and the second bar to move along the central axis of the second bar.

3. The medical device according to claim 2, wherein: The shaft includes a proximal end and a distal end; The central axis of the shaft is defined between the proximal end and the distal end of the shaft; and The shaft is operatively coupled to the first bar and the second bar, such that the shaft can rotate about the central axis of the shaft without moving the first bar or the second bar.

4. The medical device according to claim 2, wherein: The medical device also includes a link coupled to the shaft; The first and second bars are coupled to the connecting rod; and The link includes a roller drive receiver in which the shaft is rotatable relative to the link without moving the first bar or the second bar.

5. The medical device according to claim 2 or 4, wherein: The shaft includes a proximal end and a distal end; The central axis of the shaft is defined between the proximal end and the distal end of the shaft; A first signal generated by the first coil is associated with the position of the first magnet relative to the first coil, and a second signal generated by the second coil is associated with the position of the second magnet relative to the second coil; and The first signal from the first coil and the second signal from the second coil are associated with the linear displacement of the shaft along the central axis of the shaft.

6. The medical device according to claim 5, wherein: The linear displacement of the shaft is proportional to the force applied to the shaft in the direction along the central axis of the shaft.

7. The medical device according to claim 2 or 4, wherein: The shaft includes a proximal end and a distal end; The central axis of the shaft is defined between the proximal end and the distal end of the shaft; and The first coil and the second coil are secured to the mounting bracket such that the central axis of the shaft is centered between the central axis of the first rod and the central axis of the second rod.

8. The medical device according to claim 6, wherein: The central axis of the first rod and the central axis of the second rod are parallel to the central axis of the shaft.

9. The medical device according to any one of claims 1-4, wherein: The first coil has a first height, the second coil has a second height, and the first height is equal to the second height.

10. The medical device according to claim 2, wherein: The shaft includes a proximal end and a distal end; The central axis of the shaft is defined between the proximal end and the distal end of the shaft; The medical device also includes a linkage device coupled to the shaft and the mechanical structure; The linkage device includes a spring; and The spring is configured to displace proportionally to the force applied to the shaft in the direction along the central axis of the shaft.

11. The medical device according to any one of claims 1-4, wherein: A first signal generated by the first coil is associated with the position of the first magnet relative to the first coil, and a second signal generated by the second coil is associated with the position of the second magnet relative to the second coil; and The force sensor unit includes a microprocessor coupled to receive the first signal and the second signal.

12. The medical device according to claim 11, wherein: The shaft includes a proximal end and a distal end; The central axis of the shaft is defined between the proximal end and the distal end of the shaft; The first signal has a first frequency, and the second signal has a second frequency; and The microprocessor is configured to execute instructions to determine a measure of the force along the central axis of the axis based on the first frequency and the second frequency.

13. A medical device comprising: Including the proximal and distal instrument axes; A medical end effector coupled to the distal end of the instrument axis; Mechanical structure coupled to the proximal end of the instrument shaft; and A force sensor unit coupled to the mechanical structure and the instrument axis; The force sensor unit includes a first coil wound around the axis of a first coil, a second coil wound around the axis of a second coil, a first magnet, and a second magnet; The axis of the instrument shaft is defined between the proximal end and the distal end of the instrument shaft; The axis of the instrument is located between the axis of the first coil and the axis of the second coil; The first magnet is operatively coupled to the instrument shaft and moves along the first coil axis as the instrument shaft moves along the instrument shaft axis; and The second magnet is operatively coupled to the instrument axis and moves along the second coil axis as the instrument axis moves along the instrument axis.

14. The medical device according to claim 13, wherein: The medical device also includes a linkage device coupled to the instrument axis and the mechanical structure; The linkage device includes a spring; and The spring is configured to displace proportionally to the force applied to the instrument axis in a direction along the axis of the instrument axis.

15. The medical device according to claim 13 or 14, wherein: A first signal generated by the first coil is associated with the position of the first magnet relative to the first coil, and a second signal generated by the second coil is associated with the position of the second magnet relative to the second coil; and The force sensor unit includes a microprocessor configured to receive the first signal and the second signal.

16. The medical device according to claim 15, wherein: The first signal has a first frequency and the second signal has a second frequency; The microprocessor is configured to execute instructions to determine a measure of the force along the instrument axis based on the first frequency and the second frequency.

17. The medical device according to claim 13, wherein: A first signal generated by the first coil is associated with the position of the first magnet within the first coil, and a second signal generated by the second coil is associated with the position of the second magnet within the second coil; and The first signal from the first coil and the second signal from the second coil are associated with the linear displacement of the instrument axis along the axis of the instrument axis.

18. The medical device according to claim 13 or 17, wherein: The first magnet is coupled to a first rod, and the second magnet is coupled to a second rod; the first rod has a first central axis, and the second rod has a second central axis, both the first central axis of the first rod and the second central axis of the second rod being parallel to the axis of the instrument.

19. A medical device comprising: Instrument support structure, instrument shaft, and force sensor unit; The instrument axis includes a proximal end and a distal end, and the instrument axis is defined between the proximal end and the distal end of the instrument axis; The force sensor unit includes a linkage device coupled between the instrument support structure and the proximal end of the instrument shaft, a first coil wound around a first coil axis, a second coil wound around a second coil axis different from the first coil axis, a first magnet at least partially within the first coil, and a second magnet at least partially within the second coil; and The first coil, the second coil, the first magnet, and the second magnet are positioned between the linkage device of the instrument support structure and the force sensor unit, such that translation of the instrument axis along the instrument axis relative to the instrument support structure causes relative movement between the first magnet and the first coil along the first coil axis and relative movement between the second magnet and the second coil along the second coil axis.

20. The medical device according to claim 19, wherein: The linkage device includes a rotary joint, which has a rotation axis coaxial with the axis of the instrument; and The instrument shaft is coupled to the linkage of the force sensor unit to rotate about the rotation axis relative to the instrument support structure at the rotary joint.

21. The medical device according to claim 19, wherein: The medical device includes a proximal mechanical structure, a distal mechanism, and a connector; The distal mechanism is coupled to the distal end of the instrument axis and includes a movable component; The proximal mechanical structure includes the instrument support structure and an actuator input mounted to move relative to the instrument support structure; and The connector is coupled between the actuator input and the movable part of the remote mechanism, and transmits tension, compression, or both tension and compression from the actuator input to the movable part of the remote mechanism.

22. The medical device according to any one of claims 19-21, wherein: The first coil and the second coil are fixed relative to the instrument support structure.

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