Force sensing medical device

Abstract

Systems and methods for controlling a surgical system are provided. A force sensing instrument for use with a surgical system includes an instrument shaft coupled to a proximal mechanical structure. The force sensor unit is coupled to the distal end portion of the instrument shaft. The circuit board is coupled to the proximal mechanical structure and is configured to receive an output signal from the force sensor unit. The force sensor unit is coupled to the circuit board via a sensor cable configured to mitigate electromagnetic interference to the output signal. Thus, the sensor cable has a middle portion and a set of electrical traces. The electrical traces include electrical ground traces. An electrical shield surrounds a middle portion of the sensor cable and is communicatively coupled to the electrical ground trace.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority and the filing date of U.S. Provisional Patent Application No. 63 / 425,520, entitled "Force Sensing Medical Instrument", filed on November 15, 2022, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] The embodiments described herein relate to force sensing technology and, more particularly, to force sensing technology suitable for use with a remote - operated surgical system. More specifically, the embodiments described herein relate to a force - sensing medical device for determining a force applied to a medical device in order to control a surgical system that includes force feedback that can be provided to a system operator. Still more specifically, the embodiments described herein relate to the mitigation of electromagnetic interference when a force - sensing medical device is exposed to an electric field.

[0004] Known techniques for minimally invasive surgery (MIS) employ instruments that can be manually controlled or controlled via a remotely - operated medical system that is hand - held or mechanically grounded and operates at least in part in a computer - assisted manner ("remote surgical system"). Many known MIS instruments include a treatment or diagnostic end - effector (e.g., forceps, cutting tool, or cautery tool) mounted on an optional wrist mechanism at the distal end of a shaft. During an MIS procedure, the distal end of the end - effector, wrist mechanism, and shaft are typically inserted through a small incision or natural orifice of a patient via a cannula to position the end - effector at a work site within the patient. The optional wrist mechanism can be used to change the position and orientation of the end - effector relative to the shaft to perform a desired procedure at the work site. In known instruments, the movement of the instrument as a whole 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 shaft of the instrument. 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 shaft. The wrist can optionally provide a roll DOF for the end - effector, or the roll DOF can be achieved by a rolling shaft. The end - effector can optionally have additional mechanical DOF, such as a grasping or blade movement. In some cases, the wrist and end - effector mechanical DOF can be combined. For example, U.S. Patent No. 5,792,135 (filed on May 16, 1997) discloses a mechanism in which the wrist and end - effector grasping DOF are combined.

[0005] Force sensing medical devices are known and, in conjunction with associated remote surgical systems, can deliver haptic feedback to a surgeon performing a procedure during a MIS procedure. The haptic feedback can increase the surgeon's sense of immersion, realism, and intuitiveness when performing the procedure. For effective haptic rendering and accuracy, force sensors can be placed on the medical device and as close as possible to the anatomical tissue interaction. One approach is to include a force sensor unit having electrical sensor elements (e.g., strain gauges) at the distal end of the medical device shaft to measure the strain applied to the medical device. The measured strain can be used to determine the force applied to the medical device and as an input based on which the desired haptic feedback can be generated.

[0006] In some MIS procedures, an electric current is introduced into the surgical site, such as during electro-surgery. Electro-surgery broadly refers to a class of medical procedures that rely on the application of high-frequency electrical energy (usually radiofrequency energy) to patient tissue to achieve a number of possible effects, such as cutting, coagulation, necrosis, etc. For example, in some MIS procedures, tissue within a patient must be cauterized and severed. To perform such a procedure, an end effector clamp configured to apply bipolar or monopolar cautery energy is introduced into the surgical site to engage the target tissue, and electrical energy such as radiofrequency energy is delivered to the clamp to cauterize the engaged tissue. Alternatively, in some cases, a surgeon has been known to engage tissue with a conductive end effector clamp that is not specifically configured to apply electrical energy, and then place an active charging electrode (e.g., a charging end effector on a second instrument) in conductive contact with the clamp (i.e., direct electrical coupling) in order to apply electro-surgical energy to the tissue.

[0007] The force sensing instrument can be specifically designed to apply electro-surgical energy (e.g., bipolar forceps instrument), or not designed to apply electro-surgical energy (e.g., Cadiere forceps instrument). Regardless of whether the force sensing medical device is designed to apply electro-surgical energy, during certain MIS procedures, the force sensing medical device can be exposed to an electric field during an electro-surgical operation. And regardless of the method used to apply electro-surgical energy to the tissue - using an instrument specifically designed to apply electro-surgical energy or using an instrument not specifically designed to apply electro-surgical energy - the current associated with the electro-surgical energy can conduct through or along various components of the force sensing medical device.

[0008] Exposure of a force-sensing medical device to an electric field can cause electromagnetic interference to be generated within the device, which can affect signals from a force sensor unit of the force-sensing device. In turn, this effect on the signals can result in associated tactile feedback to a surgeon operating the force-sensing device and an inaccurate indication of the force acting on the force-sensing medical device. To the extent that the tactile feedback is based on an indication of the force on the device, it is desirable to mitigate the effects of electromagnetic interference. Such mitigation is subject to the design of the force-sensing device itself and design constraints (e.g., the component materials required for strength or other mechanical properties, the small component sizes required for surgery, etc.). For example, one approach attempts to employ a Faraday cage around any components that may be affected. This requires additional conductive components that encapsulate the entire sensor along the entire length of the device, effective grounding of the cage, and additional clearances. However, due to the additional components, this approach may adversely affect sensor performance (e.g., alignment, calibration, and / or robustness).

[0009] The magnitude and / or effect of electromagnetic interference on the output of the force sensor unit can also depend at least in part on the positioning of the various components of the force-sensing medical device. For example, conductive contact between an electrode and a force-sensing medical device (where the device is not specifically designed to apply electrosurgical energy) can cause current to conduct through conductive components of the force-sensing medical device (e.g., metal components such as beams, mechanical cables, and / or shafts). The conductive components can be separated from another conductive component of the force-sensing medical device (e.g., a strain sensor, strain gauge, and / or sensor cable) by electrical insulation. However, when current in the first component generates current that enters the second component through the insulation, the two conductive components can become capacitively or inductively coupled (i.e., indirectly electrically coupled). The magnitude of the generated current is affected at least in part by the positioning of the two conductive components and the insulation between them. For example, a strain sensor can be mechanically coupled to a conductive structure by an electrically insulating adhesive. According to the principle of capacitive coupling, current conducted by the structure can generate current in the strain sensor through the electrically insulating adhesive. As another example, current can also be generated in the electrical traces of a sensor cable that conveys a signal voltage from the strain sensor to a processor (e.g., one or more data processing components, a circuit board including one or more such components, a centralized or distributed data processing system including such components). The magnitude of the generated current can be affected by the distance between the sensor electronics (e.g., the strain sensor or the electrical traces) and other components, as well as by the structure determined by the thickness of the electrically insulating adhesive and other factors. To the extent that relatively low voltage variations in the strain sensor can indicate the force acting on the force-sensing medical device, the presence of electromagnetic interference (in the form of generated current) in the output of the strain sensor can distort the force indication.

[0010] In addition to capacitive coupling, electromagnetic interference can also be generated by inductive coupling (e.g., antenna coupling or magnetic field coupling) of various components of a force-sensing medical device. When inductively coupled, a magnetic field generated by a current in one conductor generates a current in a second conductor. For example, a current can be generated via inductive coupling in a strain sensor and / or a portion of a sensor cable carrying signals from the strain sensor. The presence of the current generated by inductive coupling is electromagnetic interference, which can distort the indication of strain generated by a force sensor unit, resulting in a difference in the indication of the force acting on the force-sensing medical device.

[0011] An electromagnetic interference problem can be caused by long electrical connections between sensors at the distal end of the device and one or more other electrical components at the proximal end of the device, where the one or more other electrical components need to process or otherwise transmit signals from the sensors to a user haptic feedback system. Each electrical connection line within the electrical connection cable between the distal and proximal ends of the device can each act as an antenna for receiving unwanted electromagnetic energy. Although the electromagnetic interference in the cable as a whole may be a problem, the individual electrical connection lines within the cable may pick up different amounts of electromagnetic interference, which may further degrade the sensor signals for user haptic feedback.

[0012] In addition, due to the physical design requirements of the device, a cable with electrical connection lines having sufficient separation between the distal and proximal components must be small enough to fit within the small space constraints imposed by the small diameter of the long axis of a minimally invasive surgical instrument required to minimize the size of a surgical incision. On the other hand, the cable must be large enough to ensure that each wire is large enough to be an effective electrical conductor for the sensor signals.

[0013] Furthermore, in addition to mitigating the effects of electromagnetic interference within the physical design constraints of a minimally invasive surgical instrument, it is desirable for the electronic components of a force-sensing medical device to be able to withstand post-operative process handling (e.g., cleaning, autoclaving by steam, etc.) and remain resistant to fluid ingress after post-operative process handling. For example, some known electrical couplings between components (e.g., coupling of a conventional electrical conductor cable to a circuit board) cannot withstand the high temperatures or fluid flushing pressures that may occur during post-process handling. Additionally, in known cables, an electrical insulation layer is typically located between the layer containing the electrical coupling components and the circuit board. The presence of this insulation layer can cause deformation of the layer containing the electrical coupling components to bring the electrical coupling components into contact with the circuit board. This deformation of the layer can cause delamination or detachment of a portion of the sensor cable, which then allows fluid to intrude during post-process handling.

[0014] In view of the foregoing, the art has continuously sought new and improved systems and methods for controlling a surgical system based on an accurate measurement of strain applied to a medical device. SUMMARY OF THE INVENTION

[0015] The present invention content introduces certain aspects of the embodiments described herein to provide a basic understanding. The present invention content is not an extensive overview of the subject matter of the present invention and is not intended to identify key or important elements or to depict the scope of the subject matter of the present invention.

[0016] The systems and methods described herein facilitate the control of a surgical system when a force-sensing medical device is exposed to an electric field. In particular, the force-sensing medical device uses a force sensor unit to measure the force affecting the force-sensing medical device. The output of the force sensor unit is transmitted via a sensor cable to a circuit board (e.g., to a control board) and to a controller of the system. The sensor cable is configured to mitigate the effects of electromagnetic interference. In the case where the electromagnetic effects are mitigated, the force sensor unit can transmit an output strain signal from the force sensor unit that accurately indicates the force affecting the force-sensing medical device.

[0017] In one aspect, the present disclosure relates to a force-sensing medical device ("device"). For example, the device can be used with a surgical system to perform minimally invasive surgery. The device includes a proximal mechanical structure having a plurality of drive components configured to cause movement of an end effector of the device. For example, the device can include a set of winches driven by a set of motors to change the position of the end effector (e.g., a tool member) via a set of cables. A device shaft is coupled to the proximal mechanical structure. A force sensor unit is coupled to a distal portion of the device shaft and is configured to measure the force affecting the device. A circuit board is coupled to the proximal mechanical structure and is configured to receive the output from the force sensor unit. A sensor cable having an intermediate portion and a first set of electrical traces is communicatively coupled between the force sensor unit and the circuit board. In other words, the sensor cable facilitates communication between the force sensor unit and the circuit board. The first set of electrical traces includes an electrical ground trace, and the sensor cable includes an electrical shield surrounding the intermediate portion of the sensor cable, wherein the electrical shield is communicatively coupled to the electrical ground trace.

[0018] In some embodiments, the sensor cable includes a proximal portion, a distal portion, a first layer, a proximal second layer, and a distal second layer. The first layer extends between the distal portion and the proximal portion of the sensor cable. The first layer includes a proximal section and a distal section. The proximal second layer extends parallel to the proximal section of the first layer. The distal second layer extends parallel to the distal section of the first layer. The proximal section of the first layer includes a proximal coupling interface. The proximal coupling interface includes a first set of conductive contacts. The proximal section of the first layer in the proximal portion of the sensor cable does not have the first set of electrical traces. The proximal second layer is coupled to the proximal section and includes a second set of electrical traces communicatively coupled to the set of conductive contacts.

[0019] In some embodiments, the middle portion of the sensor cable does not have a proximal second layer and a distal second layer. Additionally, a first set of electrical traces extends through the middle portion of the sensor cable in a side-by-side planar configuration within the first layer.

[0020] In some embodiments, the sensor cable includes a proximal transition portion between the proximal portion and the middle portion of the sensor cable. The proximal transition portion includes a set of through-holes configured to communicatively couple a first set of electrical traces in the first layer in the middle portion to a second set of electrical traces in the proximal second layer.

[0021] In some embodiments, the first set of electrical traces includes a set of positive traces and a set of negative traces in the middle portion of the sensor cable. Each positive trace has a first cross-sectional area, and each negative trace has a second cross-sectional area. The first cross-sectional area is less than the second cross-sectional area.

[0022] In some embodiments, a first maximum resistance limit determines a minimum first cross-sectional area of the first cross-sectional area of a set of positive traces, and a second maximum resistance limit determines a minimum second cross-sectional area of the second cross-sectional area of a set of negative traces.

[0023] In some embodiments, a maximum sensor cable width defines a maximum combined cross-sectional area of each of a set of positive traces and a set of negative traces in the middle portion of the sensor cable. The maximum sensor cable width is at least partially defined by a channel clearance of the instrument shaft.

[0024] In some embodiments, the sensor cable includes a first electrical insulation layer, an electrical insulation substrate, and a second electrical insulation layer. The first electrical insulation layer is on the distal section of the first layer and the middle portion of the sensor cable. The first electrical insulation layer is not present in the proximal section of the first layer. The electrical insulation substrate extends between the distal portion and the proximal portion of the sensor cable. The second electrical insulation layer is on the distal second layer, the middle portion of the sensor cable, and the proximal second layer.

[0025] In some embodiments, the sensor cable includes a longitudinal axis extending between the proximal portion and the distal portion. A first set of conductive contacts is arranged along a contact axis parallel to the longitudinal axis of the sensor cable.

[0026] In some embodiments, the proximal coupling interface is an anisotropic conductive film coupling.

[0027] In some embodiments, the sensor cable includes a distal transition portion between the middle portion and the distal portion of the sensor cable. The distal transition portion includes a set of through-holes configured to communicatively couple a first portion of a first set of electrical traces in the middle portion to a third set of electrical traces in the distal second layer.

[0028] In some embodiments, a distal section of a first layer in a distal portion of a sensor cable defines a distal coupling interface having a second set of conductive contacts coupled to a force sensor unit. A second portion of a first set of traces is communicatively coupled to the distal coupling interface in the first layer. A third set of traces in a distal second layer is coupled to the distal coupling interface. A linear arrangement of the second set of conductive contacts establishes an initial configuration of the third set of traces and the second portion of the first set of traces.

[0029] In some embodiments, the third set of traces and the second portion of the first set of traces are rearranged within a distal transfer portion to establish all of the traces of the first set of traces in a side-by-side planar configuration that passes through an intermediate portion of the sensor cable within the first layer.

[0030] In some embodiments, an intermediate portion of the sensor cable includes a first lateral side region and a second lateral side region separated by an electrically grounded trace. The first set of traces includes a set of positive traces and a set of negative traces in the intermediate portion of the sensor cable. The side-by-side planar configuration includes a set of positive traces positioned within the first lateral side region and a set of negative traces positioned within the second lateral side region.

[0031] In some embodiments, the first set of traces includes at least one positive trace and at least one negative trace in the intermediate portion of the sensor cable. The side-by-side planar configuration includes the positive traces and the negative traces arranged in a positive-negative pairing.

[0032] In some embodiments, a medical device includes a beam, and the beam includes a first face and a second face. The force sensor unit includes a strain sensor on the first face of the beam. The distal coupling interface is coupled to the strain sensor on the first face of the beam. A distal portion of the sensor cable is coupled to the second face of the beam adjacent to the first face of the beam. The distal coupling interface is pre-folded relative to the remainder of the distal portion to align the distal coupling interface with the first face of the beam. The size of the pre-fold corresponds to the angle between the first face of the beam and the second face of the beam.

[0033] In some embodiments, the sensor cable includes a balance portion extending distally from the distal portion of the sensor cable. The balance portion has a stiffness corresponding to the stiffness of the distal portion of the sensor cable. The balance portion does not have traces.

[0034] In some embodiments, the force sensor unit includes a strain sensor on the first face of the beam, and the strain sensor has a stiffness. A distal portion of the sensor cable is coupled to the second face of the beam adjacent to the first face of the beam. The sensor cable includes a stiffness balance tab coupled to a third face of the beam opposite the first face of the beam. The stiffness balance tab has a stiffness corresponding to the strain sensor stiffness, and the stiffness balance tab does not have traces.

[0035] In some embodiments, the strain sensor includes eight bridge circuits arranged as four bridge circuit combinations. Each of the eight bridge circuits includes two strain gauges.

[0036] In some embodiments, the sensor cable has a first longitudinal length, and the first layer has a second longitudinal length. Similarly, the proximal second layer has a third longitudinal length, and the distal second layer has a fourth longitudinal length. The second longitudinal length is equal to the first longitudinal length. The combination of the third longitudinal length and the fourth longitudinal length is less than the second longitudinal length of the first layer.

[0037] In some embodiments, the medical device includes an end effector and a wrist assembly. The end effector is coupled to the force sensor unit via the wrist assembly, and the medical device is configured to be operatively coupled to a surgical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a plan view of a minimally invasive teleoperated medical system for performing a medical procedure such as surgery according to an embodiment.

[0039] Figure 2 is Figure 1 a perspective view of a user console of the minimally invasive teleoperated surgical system shown.

[0040] Figure 3 is Figure 1 a perspective view of an optional auxiliary unit of the minimally invasive teleoperated surgical system shown.

[0041] Figure 4 is Figure 1 a front view of a manipulator unit of the minimally invasive teleoperated surgical system shown including a set of instruments.

[0042] Figure 5 is a perspective view of a force sensing medical device according to an embodiment, with the back cover removed for clarity.

[0043] Figure 6 is Figure 5 a side view of a portion of the instrument of, with the outer shaft removed.

[0044] Figure 7 is along Figure 5 in Figure 5 a cross-sectional view of the instrument taken along line X-X of.

[0045] Figure 8 is a schematic perspective view of a sensor cable for use with a force sensing instrument according to an embodiment.

[0046] Figure 9 is Figure 8 a schematic side view of the sensor cable of.

[0047] Figure 10A is taken along Figure 9 the middle portion of the sensor cable in Figure 8 and depicts a first arrangement of electrical traces according to an embodiment.

[0048] Figure 10B is taken along Figure 9 the middle portion of the sensor cable in Figure 8 and depicts a second arrangement of electrical traces according to an embodiment.

[0049] Figure 11 is taken along Figure 9 the line X2-X2 in Figure 8 and is a schematic cross-sectional view of the distal portion of the sensor cable.

[0050] Figure 12 is taken along Figure 9 the line X3-X3 in Figure 8 and is a schematic cross-sectional view of the proximal portion of the sensor cable.

[0051] Figure 13 is a perspective view of a sensor cable coupled between a force sensor unit and a circuit board according to an embodiment.

[0052] Figure 14 is the Figure 13 sensor cable coupled to the force sensor unit.

[0053] Figure 15A is Figure 14 a top view of a portion of the sensor cable, where a first electrical insulation layer is partially removed to expose an electrical shield.

[0054] Figure 15B is Figure 15A a top view of a portion of the sensor cable, where the first electrical insulation layer and the electrical shield are removed.

[0055] Figure 16A is Figure 15B a top view of a portion of the first layer of the sensor cable.

[0056] Figure 16B is Figure 15B a top view of the distal second layer and the distal coupling interface of the sensor cable.

[0057] Figure 17 is the Figure 13 sensor cable coupled to the circuit board.

[0058] Figure 18A is Figure 17 A top view of a portion of a sensor cable of

[0059] Figure 18B is Figure 18A A top view of a portion of a sensor cable of

[0060] Figure 19A is Figure 18B A top view of a portion of a first layer of a sensor cable of

[0061] Figure 19B is Figure 18B A top view of a distal second layer and a distal coupling interface of a sensor cable of

[0062] Figure 20A is Figure 14 An electrical schematic diagram of a configuration of a strain sensor of a force sensor unit as shown in

[0063] Figure 20B is Figure 14 An electrical schematic diagram of another exemplary configuration of a strain sensor of a force sensor unit as shown in

[0064] Figure 20C is Figure 20B A schematic diagram of an exemplary layout of strain gauges of a strain sensor of

[0065] Figure 21 A schematic diagram of a controller for use with a minimally invasive teleoperated surgical system according to an embodiment. DETAILED DESCRIPTION

[0066] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the present invention and not a limitation of the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the present invention. For example, features shown or described as part of one embodiment can be used with another embodiment to yield yet another embodiment. Accordingly, the present invention is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0067] The embodiments described herein can be advantageously used in a variety of grasping, cutting, and manipulation operations associated with minimally invasive surgery. The medical device or apparatus of the present application is capable of moving in three or more degrees of freedom (DOF). For example, in some embodiments, the end effector of the medical device can move relative to the body of the instrument in three mechanical DOF (e.g., pitch, yaw, and roll (axis roll)). One or more mechanical DOF can also be present within the end effector itself, such as two jaws, each jaw rotating relative to the staple (2 DOF), and the distal staple can rotate relative to the proximal staple (one DOF). Thus, in some embodiments, the medical device or apparatus of the present application can achieve movement in six DOF. The embodiments described herein can also be used to deliver haptic feedback to a system operator based on a load indication from a force sensor unit.

[0068] Generally, the present disclosure relates to systems and methods for controlling a surgical system (system), such as a remotely operated minimally invasive surgical system. In particular, the present disclosure includes a force sensor unit communicatively coupled to a circuit board via a sensor signal cable. The sensor cable is configured to mitigate electromagnetic interference. The sensor cable can be used with a force sensing medical device (instrument) to transmit an indication of the force affecting the instrument. The indication of the force can be used by the system to deliver haptic feedback to a user control unit of the system.

[0069] As described herein, the force sensor unit includes a strain sensor coupled to an elastically deformable beam. The beam is configured to deform in response to a load affecting a distal portion of the instrument. The strain sensor includes a strain gauge that measures the strain generated in the beam due to deflection. The strain sensor indicates the magnitude of the strain in the form of a relatively small voltage difference. In some embodiments, the strain gauge is arranged in a split bridge configuration (e.g., a split Wheatstone bridge), where half of the split bridge is coupled to a positive trace configured to carry a signal of a positive potential, and the other half is coupled to a negative trace configured to carry a signal of a negative potential. The voltage difference (rather than the absolute voltage) between the signal carried by the positive trace and the signal carried by the negative trace indicates the magnitude of the strain measured in the absence of electromagnetic interference.

[0070] During certain procedures, a portion of the instrument, such as a force sensor unit, may be exposed to an electric field. Such exposure can lead to the development of electromagnetic interference, which can affect the signals in the positive and / or negative traces. For example, a current conducted through a portion of the instrument, such as the instrument shaft, can induce an unintended current in another portion of the instrument, such as the sensor cable. The induced current can be generated by capacitive coupling and / or inductive coupling between various conductive components of the instrument. The magnitude of the induced current and thus the magnitude of the electromagnetic interference can be affected by the relative position and / or orientation of the various conductive components of the instrument with respect to each other and the presence of a ground shield. When the magnitude of the electromagnetic interference (i.e., the induced current) in one of the traces is greater than the magnitude of the electromagnetic interference in the other trace, the voltage difference is distorted and thus the measured strain magnitude is distorted. However, when the difference between the magnitudes of the electromagnetic interference in each of the traces is minimized, the effect of the electromagnetic interference in one trace is substantially canceled by the electromagnetic interference in the other trace, and vice versa. Therefore, it is desirable to mitigate the effect of electromagnetic interference by minimizing the difference between the induced current in the positive trace coupled to one half of the split bridge and the corresponding induced current in the negative trace coupled to the other half of the split bridge.

[0071] Insofar as relatively low voltage variations in the strain sensor can indicate the force acting on the instrument, it is desirable to minimize the resistance of the sensor cable. To this end, a maximum resistance limit can establish a minimum acceptable cross-sectional area for the positive and negative traces of the sensor cable. However, while increasing the cross-sectional area of the trace reduces the resistance of the trace (for a given trace material), the maximum size of the sensor cable and thus the maximum combined cross-sectional area of the traces are limited by the internal structure of the instrument shaft through which the cable is routed. For example, the sensor cable can have a maximum width that is at least partially defined by the channel clearance of the instrument shaft. Additionally, it is desirable for the sensor cable to be sufficiently flexible to facilitate movement of the end effector during operation. To this end, the electrical traces can be arranged in a single side-by-side planar configuration in a portion of the sensor cable within the instrument shaft. To mitigate the effect of electromagnetic interference, this portion of the sensor cable can be electrically shielded via a shield layer coupled to a ground trace. Further mitigation of the effects of electromagnetic interference can be achieved via various arrangements of the positive and negative traces within the sensor cable.

[0072] As described herein, it is also desirable for the sensor cable to be formed to facilitate post - processing (e.g., autoclaving) of the medical device. To this end, the sensor cable can be formed to facilitate a sealed coupling (e.g., connection or contact) with the circuit board and the force sensor unit. For example, the sensor cable can include a layer having a set of electrical coupling members positioned to couple to the circuit board. Specifically, the sensor cable described herein can be formed such that the sensor cable can be coupled to the circuit board without flexure or deformation of the layer. This arrangement minimizes residual strain in the sensor cable near the point of electrical coupling, thereby reducing the likelihood that the sensor cable will become detached from the circuit board.

[0073] Additionally, as described herein, a portion of the sensor cable can be coupled to the beam of the force sensor unit. However, this coupling can increase the stiffness of the corresponding portion of the beam. This increase in stiffness can affect the degree of deflection of the corresponding portion of the beam, resulting in distortion of the sensed strain at various points along the beam. Thus, the sensor cable can include a balance portion extending distally from the distal portion of the sensor cable. The balance portion can have a stiffness corresponding to the stiffness of the portion of the sensor cable coupled to the beam, but does not include any electrical traces. For example, the balance portion can have a stiffness equal to (or substantially equal to) the stiffness of the portion of the sensor cable coupled to the beam. As another example, the balance portion can have a stiffness such that, together with the portion of the beam to which the balance portion is coupled, it produces deflection characteristics similar to those produced by the portion of the sensor cable coupled to the beam. Thus, the increase in the stiffness of the beam can be uniform along the length of the beam, resulting in uniformity of the sensed strain along the beam. In other words, the balance portion can be used to reduce the effect of any stiffness concentration caused by the positioning of the sensor cable on the beam.

[0074] As used herein, the term "about", when used in conjunction with a reference numeral indication, means plus or minus up to 10 percent of the reference numeral indication. For example, the language "about 50" encompasses the range from 45 to 55. Similarly, the language "about 5" encompasses the range from 4.5 to 5.5.

[0075] As used in this specification and the appended claims, the word "distal" refers to the direction toward the working site, and the word "proximal" refers to the direction away from the working site. Thus, for example, the end of the tool closest to the target tissue will be the distal end of the tool, and the end opposite the distal end (i.e., the end manipulated by the user or coupled to the actuation shaft) will be the proximal end of the tool.

[0076] In addition, the specific words chosen to describe one or more embodiments and optional elements or features are not intended to limit the invention. For example, spatially relative terms—such as "below," "beneath," "lower," "above," "upper," "proximal," "distal," etc.—may be used to describe the relationship of one element or feature to another 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 position and orientation shown in the figures. For example, if the device in the figures is turned over, an element described as "below" or "beneath" another element or feature will then be "above" or "over" the other element or feature. Thus, the term "below" can encompass both the position and orientation of above and below. The device may be otherwise oriented (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein are to be interpreted accordingly. Similarly, descriptions of movement along (translation) and around (rotation) various axes include a variety of spatial device positions and orientations. A combination of a body's position and orientation defines the body's pose (e.g., a kinematic pose).

[0077] Similarly, unless the context indicates otherwise, geometric terms such as "parallel," "perpendicular," "circular," or "square" are not intended to require absolute mathematical precision. Instead, such geometric terms allow for variations due to manufacturing or equivalent functionality. For example, if an element is described as "circular" or "substantially circular," a component that is not precisely circular (e.g., a component that is slightly oval or faceted polygonal) is still covered by that description.

[0078] In addition, unless the context indicates otherwise, the singular forms "a," "an," and "the" are also intended to include the plural forms. The terms "comprising," "including," "having," etc. 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.

[0079] Unless otherwise indicated, the terms "device," "medical device," "instrument," "medical instrument," "surgical instrument," and their variants may be used interchangeably.

[0080] Aspects of the invention are described with reference to a teleoperated surgical system. An example architecture of such a teleoperated surgical system is the da commercialized by Intuitive Surgical Inc., Sunnyvale, California Surgical systems. 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 implementations are presented only as examples and should not be considered as limiting the scope of the inventive aspects disclosed herein. Where applicable, aspects of the present invention can be embodied and implemented in both relatively small hand-held manually operated devices and relatively large systems with additional mechanical supports.

[0081] Figure 1 FIG. is a plan view illustration of a remotely operated surgical system (“system”) 1000 (“remote surgical system”) that operates under at least partial computer assistance. Both the remote surgical system 1000 and its components are considered medical devices. The remote surgical system 1000 is a minimally invasive robotic surgery (MIRS) system for performing minimally invasive diagnostic or surgical procedures on a patient P lying on an operating table 1010. The system can have any number of components, such as a user control unit 1100 for use by an operator of the system (e.g., a surgeon or other skilled clinician S) during the procedure. The MIRS system 1000 can also include a manipulator unit 1200 (commonly referred to as a surgical robot) and an optional accessory device unit 1150. The manipulator unit 1200 can include an arm assembly 1300 and a surgical instrument tool assembly removably coupled to the arm assembly. The manipulator unit 1200 can manipulate at least one removably coupled medical device (instrument) 1400 (e.g., a force-sensing medical device) through a minimally invasive incision or natural orifice in the patient P while the surgeon S observes the surgical site and controls the movement of the instrument 1400 through the control unit 1100. Images of the surgical site are obtained by an endoscope (not shown), such as a stereoscopic endoscope, which can be manipulated by the manipulator unit 1200 to orient the endoscope. The accessory device unit 1150 can be used to process the images of the surgical site for subsequent display to the surgeon S through the user control unit 1100. The number of single-use instruments 1400 typically depends on factors such as the diagnostic or surgical procedure and space limitations in the operating room. If one or more of the instruments 1400 in use need to be replaced during the procedure, an assistant removes the instrument 1400 from the manipulator unit 1200 and replaces it with another instrument 1400 from a tray 1020 in the operating room. Although shown for use with the instrument 1400, any instrument described herein can be used with the system 1000.

[0082] Figure 2is a perspective view of the user control unit 1100. The user control unit 1100 includes a left-eye display 1112 and a right-eye display 1114 for presenting a coordinated stereoscopic view of the surgical site enabling depth perception to the surgeon S. The user control unit 1100 also includes one or more input control devices 1116 (input devices), and the one or more input control devices 1116 in turn cause the manipulator unit 1200 ( Figure 1 as shown) to manipulate one or more tools. The input devices 1116 provide at least the same degrees of freedom as the instruments 1400 with which they are associated, to provide the surgeon S with a sense of telepresence, or a perception that the input devices 1116 are integral 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 directly controlling the instruments 1400. To this end, position, force, strain, or tactile feedback sensors (not shown) or any combination of such sensations are returned from the instruments 1400 to one or more hands of the surgeon through the one or more input devices 1116.

[0083] Figure 1 The user control unit 1100 shown is in the same room as the patient, such that the surgeon S can directly monitor the procedure, and if needed, the surgeon S can be physically present and speak directly to an assistant, rather than speaking to the assistant over the phone or other communication medium. However, in other embodiments, the user control unit 1100 and the surgeon S can be in different rooms, completely different buildings, or other locations remote from the patient, thereby allowing a remote surgical procedure.

[0084] Figure 3 is a perspective view of the auxiliary device unit 1150. The auxiliary device unit 1150 can be coupled to an endoscope (not shown) and can include one or more processors to process the captured images for subsequent display, for example, via the user control unit 1100, or on another suitable display located locally (e.g., on the unit 1150 itself shown, on a wall-mounted display) and / or remotely. For example, in the case of using a stereoscopic endoscope, the auxiliary device unit 1150 can process the captured images to present a coordinated stereoscopic image of the surgical site to the surgeon S via the left-eye display 1112 and the right-eye display 1114. Such coordination can include alignment between the relative images and can include adjusting the stereoscopic working distance of the stereoscopic endoscope. As another example, the image processing can include compensating for imaging errors of the image capture device, such as optical aberrations, using previously determined camera calibration parameters.

[0085] Figure 4A front perspective view of the manipulator unit 1200 is shown. The manipulator unit 1200 includes components for providing manipulation of the instrument 1400 (e.g., arms, linkages, motors, sensors, etc.) and an imaging device (not shown) for capturing images of the site of the procedure, such as a stereoscopic endoscope. Specifically, the instrument 1400 and the imaging device can be manipulated by a remote operating mechanism having one or more mechanical joints. Further, the instrument 1400 and the imaging device are positioned and manipulated through an incision or natural orifice within the patient P such that the center of motion, which is remote from the manipulator and generally located at a position along the instrument axis, is maintained at the incision or orifice by kinematic mechanical or software constraints. In this way, the incision size can be minimized.

[0086] Now referring to Figures 5 to 7 , in Figure 5 a perspective view of the instrument 1400 is depicted, in Figure 6 a side view of a portion of the instrument 1400 with the outer shaft portion removed is depicted, and in Figure 7 a cross-sectional view of the instrument 1400 is depicted. In some embodiments, the instrument 1400 or any component thereof is optionally part of a surgical system for performing a surgical procedure, and it can include a manipulator unit, a series of motion linkages, a set of cannulas, etc. The instrument 1400 (and any instrument described herein) can be used with any suitable surgical system, such as the MIRS system 1000 shown and described above. As Figure 5 shown, the instrument 1400 includes a proximal mechanical structure 1700 (depicted with the outer cover removed), a shaft 1410, a distal portion 1402, and a set of cables (not shown). The cables serve as tension elements for coupling the proximal mechanical structure 1700 to the distal portion 1402. In some embodiments, the distal portion 1402 includes a distal wrist assembly 1500 and a distal end effector 1460. The instrument 1400 is configured such that movement of one or more of the cables produces movement of the end effector 1460 about the axes of the beam coordinate system (e.g., pitch, yaw, or grasp).

[0087] The proximal mechanical structure 1700 is configured to be removably coupled to the arm assembly 1300 of the manipulator unit 1200 ( Figure 4)。The manipulator unit 1200 includes a remote actuator (e.g., a motor with a coupled drive disk) to provide control motion to the instrument 1400, which is translated into various movements of one or more tools at the distal portion 1402 of the instrument 1400. When the instrument 1400 is coupled to the arm assembly 1300, an input (“master” command) provided by the surgeon S to the user control unit 1100 is converted by the instrument 1400 via the drive disk of the arm assembly 1300 into a corresponding action (“slave” response), the drive disk of the arm assembly 1300 being operatively coupled to the instrument disk 1740 on the instrument 1400.

[0088] In some embodiments, the proximal mechanism 1700 includes a circuit board 1920 (e.g., a control board). The circuit board 1920 is communicatively coupled to the force sensor unit 1800 via a sensor cable 1840. The circuit board 1920 is configured to provide a voltage input to the strain sensors 1830 of the force sensor unit 1800 and receive an output signal from the strain sensors 1830 indicative of the forces affecting the distal portion 1402 of the instrument 1400. Further details regarding the circuit board 1920 are provided in U.S. Provisional Patent Application No. 63 / 425,524, filed Nov. 15, 2022, the disclosure of which is incorporated herein by reference for all purposes. Further details regarding the force sensor unit 1800 are provided in co-pending U.S. Provisional Patent Application No. 63 / 425,518, filed Nov. 15, 2022, the disclosure of which is incorporated herein by reference for all purposes.

[0089] In addition, although the proximal mechanism 1700 is shown as including a winch 1720, in other embodiments, the mechanism may include one or more linear actuators that produce a translation (linear motion) of a portion of the cable. Such a proximal mechanism may include, for example, a gimbal, a lever, or any other suitable mechanism to directly pull (or release) an end portion of any cable. For example, in some embodiments, the proximal mechanism 1700 may include any proximal mechanism or component described in U.S. Patent Application Publication No. US2015 / 0047454 A1, titled “Lever Actuated Gimbal Plate” (filed Aug. 15, 2014) or U.S. Patent No. US 6,817,974 B2, titled “Surgical Tool Having Positively Positionable Tendon-Actuated Multi-Disc Wrist Joint” (filed Jun. 28, 2001), the entire contents of each of the above U.S. patents being incorporated herein by reference.

[0090] Still referring to Figures 5 to 7 , shaft 1410 can be any suitable elongated shaft coupled to wrist assembly 1500 and proximal mechanism 1700. Specifically, shaft 1410 includes a proximal end 1411 coupled to proximal mechanism 1700 and a distal portion 1412 coupled to wrist assembly 1500 (e.g., the proximal link of wrist assembly 1500). Shaft 1410 defines a channel or series of channels through which cables and other components can be routed from proximal mechanism 1700 to wrist assembly 1500. For example, as Figure 7 depicted in, shaft 1410 defines a sensor cable channel 1413 through which sensor cable 1840 is routed. Sensor cable channel 1413 has a channel gap W2 that can define a maximum sensor cable width (e.g., the maximum sensor cable width W1 depicted in Figure 10A ).

[0091] In some embodiments, shaft 1410 can be formed at least in part of a conductive material such as stainless steel. In such embodiments, the shaft can include either an inner insulating cover or an outer insulating cover. Thus, shaft 1410 can be a shaft assembly that includes multiple different components. For example, shaft 1410 can include (or be coupled to) a spacer that provides a desired fluid seal, electrical insulation features, and any other desired components for coupling wrist assembly 1500 to shaft 1410. Similarly, although wrist assembly 1500 (and other wrist assemblies or links described herein) are described as being coupled to shaft 1410, it should be understood that any wrist assembly or link described herein can be coupled to the shaft via any suitable intermediate structure such as spacers and cable guides, etc.

[0092] As Figure 6As depicted, instrument 1400 (e.g., a force-sensing medical instrument) includes a force sensor unit 1800. The force sensor unit includes a beam 1810 having one or more strain sensors 1830. The strain sensors 1830 can include a set of strain gauges (e.g., tensile strain gauge resistors or compressive strain gauge resistors) arranged to be mounted in at least one bridge circuit (e.g., a Wheatstone bridge) along the surface of the beam 1810. In some embodiments, the end effector 1460 can be coupled at the distal portion 1815 (e.g., the distal portion 1402 of the surgical instrument 1400) of the beam 1810 via a wrist assembly 1500. The shaft 1410 includes a distal portion 1412 (e.g., an inner shaft) coupled to the proximal portion 1813 of the beam 1810. In some embodiments, the distal portion 1412 of the shaft 1410 is coupled to the proximal portion 1813 of the beam 1810 via another coupling member (e.g., an anchor or a coupler, not shown). In some embodiments, the force sensor unit 1800 can include any structure or component described in U.S. Patent Application Publication No. US 2020 / 0278265A1, entitled "Split Bridge Circuit Force Sensor," filed on May 13, 2020, the entire contents of which are incorporated herein by reference.

[0093] In some embodiments, the end effector 1460 can include at least one tool member 1462 having a contact portion configured to engage or manipulate target tissue during a surgical procedure. For example, in some embodiments, the contact portion can include an engagement surface that serves as a clamp, a cutter, a tissue manipulator, etc. In other embodiments, the contact portion can be an energized tool member for cauterization or electrosurgical procedures. The end effector 1460 can be operably coupled to a proximal mechanical structure 1700 such that the tool member 1462 rotates relative to the shaft 1410. In this manner, the contact portion of the tool member 1462 can be actuated to engage or manipulate target tissue during a surgical procedure. The tool member 1462 (or any tool member described herein) can be any suitable medical tool member. Additionally, although only one tool member 1462 is identified, as shown, the instrument 1400 can include two tool members that cooperate to perform a grasping or shearing function. In other embodiments, the end effector can include more than two tool members.

[0094] Figure 8 is a schematic perspective view of a sensor cable 2840 for use with instrument 1400 (or any of the instruments described herein), and Figure 9is a schematic side view of the sensor cable 2840. The sensor cable 2840 can be used, for example, to communicatively couple a force sensor unit 1800 (or any of the force sensor units described herein) to a circuit board 1920 (or any of the circuit boards described herein). Thus, in some embodiments, the sensor cable 2840 can extend within the instrument shaft 1410 between the proximal mechanical structure 1700 and the force sensor unit 1800. It should be understood that some embodiments of the sensor cable 2840 do not require each and every optional element, component, and / or feature depicted.

[0095] As depicted, the sensor cable 2840 includes an intermediate portion 2841 between a proximal portion 2842 and a distal portion 2843. The intermediate portion 2841 of the sensor cable 2840 includes a first set of electrical traces 2890. The first set of electrical traces 2890 can communicatively couple a force sensor unit (not shown) configured to measure forces affecting the instrument to a circuit board (not shown) configured to receive an output from the force sensor unit. The first set of electrical traces 2890 includes an electrical ground trace 2891( Figure 10A ). The electrical ground trace 2891 can electrically ground the force sensor unit to the circuit board. In some embodiments, the sensor cable 2840 includes an electrical shield 2844 around the intermediate portion 2841 of the sensor cable 2840.

[0096] In some embodiments, the electrical shield 2844 is communicatively coupled to the electrical ground trace 2891. The electrical shield 2844 can be, for example, a conductive material (e.g., a metal film, a helical wire bundle, or other similar conductive structure) radially outward from the first set of electrical traces 2890. In some embodiments, as depicted, the electrical shield 2844 can extend along the upper and lower sides of the intermediate portion 2841. However, in additional embodiments, the electrical shield 2844 can surround the intermediate portion 2841. The electrical shield 2844 can, for example, limit the transmission of electromagnetic radiation to the first set of electrical traces 2890 and thus mitigate the effect of electromagnetic interference on the signals transmitted by the sensor cable 2840. In other words, the electrical shield 2844 can electrically isolate the first set of electrical traces 2890 from other conductive components of the instrument, such as the instrument shaft.

[0097] Still referring to Figure 8 and Figure 9, in some embodiments, the sensor cable 2840 includes a first layer 2860, a proximal second layer 2870, and a distal second layer 2880. The first layer 2860 extends between a distal portion 2843 and a proximal portion 2842 of the sensor cable 2840. The first layer 2860 includes a proximal section 2861 within the proximal portion 2842 of the sensor cable 2840. The first layer 2860 also includes a distal section 2862 within the distal portion 2843 of the sensor cable 2840. In other words, the first layer 2860 extends along the entire sensor cable 2840. In some embodiments, the proximal second layer 2870 extends parallel to the proximal section 2861 of the first layer 2860 within the proximal portion 2842 of the sensor cable 2840. Similarly, the distal second layer 2880 extends parallel to the distal section 2862 of the first layer 2860 within the distal portion 2843 of the sensor cable 2840. In some embodiments, the middle portion 2841 of the sensor cable 2840 does not have the proximal second layer 2870 and the distal second layer 2880. In such embodiments, the first set of electrical traces 2890 may extend through the middle portion 2841 of the sensor cable 2840 in a side-by-side planar configuration within the first layer 2860. In other words, neither the proximal second layer 2870 nor the distal second layer 2880 extends the entire length of the sensor cable 2840.

[0098] In some embodiments, the sensor cable 2840 has a first longitudinal length LL1. The first longitudinal length LL1 corresponds to the entire longitudinal length of the sensor cable 2840. The first layer 2860 has a second longitudinal length LL2. The second longitudinal length LL2 is equal to the first longitudinal length LL1. In other words, since the first layer 2860 extends the length of the sensor cable 2840, the first layer 2860 and the sensor cable 2840 have the same longitudinal length. The proximal second layer 2870 has a third longitudinal length LL3, and the distal second layer 2880 has a fourth longitudinal length LL4. The combination of the third longitudinal length LL3 and the fourth longitudinal length LL4 is less than the second longitudinal length LL2 of the first layer 2860. In other words, the combined longitudinal length of the proximal second layer 2870 and the distal second layer 2880 is less than the longitudinal length of the first layer 2860. It should be understood that the longitudinal length of the sensor cable 2840 corresponds to the length along the longitudinal axis A LO of.

[0099] Still referring to Figure 8 and Figure 9 , and also referring to Figure 12 , in some embodiments, the proximal section 2861 of the first layer 2860 includes a proximal coupling interface 2863. The proximal coupling interface 2863 includes a first set of conductive contacts (e.g., as Figure 18AThe depicted conductive contact 3864). The proximal section 2861 of the first layer 2860 in the proximal portion 2842 of the sensor cable 2840 does not have the first set of electrical traces 2890. In other words, the proximal section 2861 does not contain any electrical traces and thus defines a non-conductive region extending across the width of the first layer 2860 (e.g., along the transverse axis A LA ) between the first set of electrical traces 2890 in the first layer 2860 and the proximal coupling interface 2863. However, the proximal second layer 2870 is coupled to the proximal section 2861 and includes a second set of electrical traces 2896. The second set of electrical traces 2896 is communicatively coupled between the conductive contacts of the proximal coupling interface 2863 of the first layer 2860 and the first set of electrical traces 2890. In other words, during operation, the output signal from the force sensor unit can be transmitted proximally along the first set of electrical traces 2890 within the first layer 2860 to the proximal transfer portion 2845, where the first set of electrical traces 2890 terminates, and the output signal can be transmitted via the proximal coupling interface 2863 to the second set of electrical traces 2896 and onto the circuit board.

[0100] As depicted, the proximal transfer portion 2845 is positioned between the proximal portion 2842 and the intermediate portion 2841 of the sensor cable 2840. The proximal transfer portion 2845 includes a set of vias 2846. Each via 2846 can be, for example, a conductive element or structure inserted or formed through two or more adjacent layers of the sensor cable 2840. Thus, each via 2846 is an electrical connection between the first set of electrical traces 2890 in the first layer 2860 and the second set of electrical traces 2896 in the proximal second layer 2870. In other words, the set of vias 2846 within the proximal transfer portion 2845 is configured to communicatively couple the first set of electrical traces 2890 in the first layer 2860 in the intermediate portion 2841 to the second set of electrical traces 2896 in the proximal second layer 2870 in the proximal portion 2842 of the sensor cable 2840. In some embodiments, the proximal transfer portion 2845 can facilitate the rearrangement of the electrical traces to establish a trace arrangement consistent with the arrangement of the electrical contacts on the circuit board.

[0101] As Figures 8 to 12 depicted, in some embodiments, the sensor cable 2840 includes a first electrical insulation layer 2847, an electrical insulation substrate 2848, and a second electrical insulation layer 2849. The first electrical insulation layer 2847 is on the distal section 2862 of the first layer 2860 (as Figure 11 shown) and the intermediate portion 2841 of the sensor cable 2840 (as Figures 10A to 10Bas shown). The electrically insulating substrate 2848 extends between the distal portion 2843 and the proximal portion 2842 of the sensor cable 2840. The second electrically insulating layer 2849 is on the distal second layer 2880, the intermediate portion 2841 of the sensor cable 2840, and the proximal second layer 2870, as Figure 8 and Figure 9 depicted. In other words, the second electrically insulating layer 2849 extends along the entire longitudinal length of the sensor cable 2840.

[0102] As Figure 8 , Figure 9 and Figure 12 depicted, the first electrically insulating layer 2847 is not present in the proximal section 2861 of the first layer 2860. In other words, since the first set of electrical traces 2890 terminate in the proximal transfer portion 2845 such that the proximal section 2861 of the first layer 2860 does not contain electrical traces, an electrically insulating proximal section 2861 is not needed. Accordingly, the first electrically insulating layer 2847 can terminate at the junction of the proximal transfer portion 2845 and the proximal portion 2842 of the sensor cable 2840. By preventing the first electrically insulating layer 2847 from extending onto the proximal section 2861, the proximal section 2861 can remain in a neutral orientation when the proximal coupling interface 2863 is coupled to a circuit board. In other words, the absence of the first electrically insulating layer 2847 on the proximal section 2861 obviates the need to bend or deform the first layer 2860 to bring a set of electrical contacts of the proximal coupling interface 2863 into contact with the circuit board. Since the thickness of the first electrically insulating layer 2847 is absent between the proximal section 2861 and the circuit board, the planar nature of the proximal section 2861 can be maintained and the separating forces otherwise generated by bending / flexing between the respective layers of the sensor cable 2840 are reduced or eliminated. Similarly, the proximal section 2861 is flush-coupled to the surface of the circuit board without any residual resilience that might be present if there were a step or discontinuity between the proximal section 2861 and the circuit board. This in turn reduces or eliminates delamination of the sensor cable 2840 when coupled to the circuit board, thus facilitating post-processing of the device.

[0103] Figure 10Ais a schematic cross-sectional view of an intermediate portion 2841 of a sensor cable 2840 taken along line X1-X1. As depicted, a first set of electrical traces 2890 includes positive traces 2892 and negative traces 2893 in the intermediate portion 2841 of the sensor cable 2840. In some embodiments, each positive trace 2892 is configured to carry a signal at a positive potential. Similarly, in some embodiments, each negative trace is configured to carry a signal at a negative potential. In some embodiments, the positive traces 2892 are traces that are electrically coupled to the distal portion of the strain sensor (e.g., the primary distal bridge circuit combination 3832 and the secondary distal bridge circuit combination 3836 described below), while the negative traces 2893 are traces that are electrically coupled to the proximal portion of the strain sensor (e.g., the primary proximal bridge circuit combination 3834 and the secondary proximal bridge circuit combination 3838 described below). Each positive trace 2892 has a first cross-sectional area CA1. Each negative trace 2893 has a second cross-sectional area CA2. In some embodiments, the first cross-sectional area CA1 is less than the second cross-sectional area CA2. Accordingly, the positive traces 2892 have a higher resistance value than the negative traces 2893. For example, the positive traces 2892 may have a resistance of less than 20 ohms (e.g., less than 17 ohms), while the negative traces 2893 may have a resistance of less than 10 ohms (e.g., less than 7 ohms).

[0104] In some embodiments, a first maximum resistance limit determines a minimum first cross-sectional area CA1 of the positive traces 2892. Similarly, a second maximum resistance limit determines a minimum second cross-sectional area CA2 of the negative traces 2893. In other words, while it may be desirable to minimize the cross-sectional area of the first set of electrical traces 2890 to minimize the width and / or thickness of the sensor cable 2840 (due to size limitations within the instrument shaft and the desired flexibility of the sensor cable 2840), the maximum resistance limits establish the boundary at which a further reduction in the cross-sectional area would negatively impact the transmission of the signal. Correlatively, in some embodiments, a maximum sensor cable width W1 defines a maximum combined cross-sectional area of each of the positive traces 2892 and each of the negative traces 2893 in the intermediate portion 2841 of the sensor cable 2840. The maximum sensor cable width W1 is at least partially determined by the channel clearance of the instrument shaft (e.g., as Figure 7is defined by the depicted channel gap W2). In other words, although it may be desirable to maximize the cross-sectional area of the first set of electrical traces 2890 to reduce resistance, dimensional limitations within the instrument shaft establish an upper bound on the width of the sensor cable. Thus, the maximum resistance limit establishes a lower bound on the cross-sectional area of the traces and thus a corresponding lower bound on the width and thickness of the sensor cable 2840, while the dimensional limitations imposed by the instrument establish an upper bound on the width of the sensor cable 2840 and thus an upper bound on the cross-sectional area of the traces. It should be understood that the positive traces 2892 and the negative traces 2893 may be connected to different circuitry on the circuit board, which may result in different interference effects.

[0105] Referring again to Figure 8 and Figure 9 and also referring to Figure 11 in some embodiments, the sensor cable includes a distal transfer portion 2850. The distal transfer portion 2850 is positioned between an intermediate portion 2841 and a distal portion 2843 of the sensor cable 2840. The distal transfer portion 2850 includes a set of vias 2846. Each via 2846 may be, for example, a conductive element or structure inserted through or formed in two or more adjacent layers of the sensor cable 2840. Thus, each via 2846 is an electrical connection between a first portion of the first set of electrical traces 2890 in a first layer 2860 and a third set of electrical traces 2897 in a distal second layer 2880. In other words, the set of vias 2846 within the distal transfer portion 2850 is configured to communicatively couple a first portion of the first set of electrical traces 2890 in the first layer 2860 in the intermediate portion 2841 to a third set of electrical traces 2897 in the distal second layer 2880 in the distal portion 2843 of the sensor cable 2840.

[0106] In some embodiments, a distal section 2862 of the first layer 2860 in the distal portion 2843 of the sensor cable 2840 defines a distal coupling interface 2867. The distal coupling interface 2867 includes a second set of conductive contacts (e.g., such as the conductive contacts 3868 depicted in Figure 14 coupled to a force sensor unit (e.g., such as the force sensor unit 3400 depicted in Figure 15A ). A second portion 2895 of the first set of electrical traces 2890 is communicatively coupled to the distal coupling interface 2867 in the first layer 2860 in the distal portion 2843. The distal section 2862 includes electrical traces and is thus covered with a first electrical insulation layer 2847 as compared to the proximal section 2861. The third set of electrical traces 2897 in the distal second layer 2880 is coupled to the distal coupling interface 2867.

[0107] In some embodiments, the linear arrangement of the second set of conductive contacts of the distal coupling interface 2867 establishes an initial configuration of the third set of electrical traces 2897 and the second portion 2895 of the first set of electrical traces 2890. As a cross-sectional view of the distal portion 2843, Figure 11 depicts the initial configuration of the electrical traces in the distal portion. As depicted, in some embodiments, the positive trace 2892 is positioned within the distal section 2862 of the first layer 2860. The negative trace 2893 and the electrical ground trace 2891 are positioned within the second distal layer 2880. In some embodiments, the third set of electrical traces 2897 and the second portion 2895 of the first set of electrical traces 2890 are rearranged within the distal transfer portion 2850. This rearrangement establishes all of the electrical traces of the first set of electrical traces 2890 in a side-by-side planar configuration that passes through the middle portion 2841 of the sensor cable 2840 within the first layer 2860. In other words, the distal transfer portion 2850 facilitates the electrical traces in Figure 11 the depicted arrangement and Figure 10A or Figure 10B the depicted arrangement.

[0108] As Figure 10A depicted, in some embodiments, the middle portion 2841 of the sensor cable 2840 includes a first lateral side region 2851 and a second lateral side region 2852 separated by the electrical ground trace 2891. In some embodiments, the positive trace 2892 is positioned within the first lateral side region 2851. Similarly, the negative trace 2893 is positioned within the second lateral side region 2852. Thus, the positive trace 2892 is separated from the negative trace 2893 by the electrical ground trace 2891. Accordingly, electromagnetic interference between the positive trace 2892 and the negative trace 2893 can be mitigated by the electrical ground trace 2891 positioned therebetween.

[0109] Similar to Figure 10A that, Figure 10B is also a schematic cross-sectional view of the middle portion 2841 of the sensor cable 2840, but in which the first set of electrical traces 2890 are positioned in a different arrangement. As Figure 10BDepicted, the first set of electrical traces 2890 includes at least one positive trace 2892 and at least one negative trace 2893 in the middle portion 2841 of the sensor cable 2840. The positive trace 2892 and the negative trace 2893 are arranged as a positive-negative pair PN1. For example, as depicted, in some embodiments, the first set of electrical traces 2890 may include four positive-negative pairs PN1, PN2, PN3, PN4. As described more fully below, each of the four positive-negative pairs may correspond to one of the four bridge circuits of the strain sensor. When arranged as a positive-negative pair, the induced current in the positive trace 2892 will be substantially equal to the induced current in the adjacent negative trace 2893. This equalization of the induced current results in the cancellation of the effect of electromagnetic interference on the signals transmitted by the positive-negative pair of electrical traces. In other words, since the induced current in each of the positive-negative paired electrical traces has substantially the same value, the voltage of the output signal delivered to the circuit board may have a greater magnitude, but the increase in the voltage magnitude does not affect the voltage difference and thus does not affect the indication of strain.

[0110] Figures 13 to 20C Depicted are various views of aspects of a force sensor unit 3800 coupled to a circuit board 3920 via a sensor cable 3840 for use with a force sensing medical device such as the device 1400 described herein. In some embodiments, any one of the force sensor unit 3800, the circuit board 3920, the sensor cable 3840, and / or their components is optionally part of a surgical system that performs a surgical procedure. The surgical system may include a manipulator unit, a series of motion linkages, a series of cannulas, etc. The force sensing medical device may include an instrument shaft coupled to a proximal mechanical structure, a force sensor unit 3800 coupled to the instrument shaft, and an end effector coupled to the force sensor unit 3800 via a wrist assembly as previously described. The force sensor unit 3800, the circuit board 3920, and / or the sensor cable 3840 (and any one of the force sensor units, circuit boards, and / or sensor cables described herein) may be used in any suitable surgical system, such as the MIRS system 1000 shown and described above, to mitigate the effects of electromagnetic interference when the instrument is exposed to an electric field.

[0111] As depicted, the force sensor unit 3800 includes a beam 3810. The beam 3810 is an elastically deflectable beam configured to bend or deflect in response to a load applied to the distal portion of the instrument. A strain sensor 3830 is mounted on a first face 3812 (e.g., a side face) of the beam 3810 to sense the strain generated by the deflection of the beam 3810. The first face 3812 extends along the longitudinal axis A of the beam 3810 LO and the transverse axis A LA ( Figure 5) Extension. For example, the beam 3810 can couple the distal portion of the instrument (e.g., distal portion 1402( Figure 5 )) to the shaft of the instrument (e.g., shaft 1410( Figure 5 )) in a cantilever configuration that is anchored at the proximal portion of the beam 3810.

[0112] The strain sensor 3830 is optionally made of one or more electrical strain sensing circuits (e.g., half - bridge circuit 3831 (e.g., see Figures 20A to 20C )) and other strain sensor configurations (e.g., piezoelectric sensors, etc.) are contemplated. As described herein, each half - bridge circuit 3831 (and each strain sensor) includes one or more strain gauges 3833 (e.g., tensile strain gauge resistors or compressive strain gauge resistors). It should be understood that the beam 3810 can include any number of strain sensors 3830 in various arrangements. In some embodiments, the beam 3810 includes a single strain sensor 3830 that includes multiple split half - bridge circuits 3831, where each split half - bridge circuit 3831 has at least two strain gauges 3833.

[0113] During certain operations, when exposed to an electric field, the beam 3810 can be capacitively coupled to the strain sensor 3830, and the orthogonal distance between the first face 3812 of the beam 3810 and the strain gauges 3833 of the strain sensor 3830 can affect the current induced in the strain gauges 3833. When the distance between the strain gauges 3833 and the first face 3812 is uniform, the induced current in each of the strain gauges 3833 is substantially equal to the induced current in each other strain gauge 3833. This equalization of the induced current results in the cancellation of the effect of electromagnetic interference in the output of the strain sensor 3830. In other words, since the induced current in each of the strain gauges 3833 has substantially the same value, the voltage of the output signal can have a greater magnitude, but the increase in the voltage magnitude does not affect the voltage difference and thus does not affect the indication of strain. However, variations in the flatness of the first face 3812 and / or the thickness of the adhesive coupling the strain gauges 3833 to the beam 3810 can result in a lack of uniformity in the distance between the strain gauges 3833 and the first face 3812 and a corresponding variation in the induced current, which in turn manifests as electromagnetic interference in the output signal of the strain sensor 3830. Thus, in some embodiments, the force sensor unit 3800 disclosed herein utilizes a conductive layer and an electrically insulating layer to facilitate uniform capacitive coupling when the force sensor unit 3800 is exposed to an electric field. Further details regarding the uniform capacitive coupling of the force sensor unit 3800 are provided in U.S. Provisional Patent Application No. 63 / 425,518, filed on November 15, 2022, the disclosure of which is incorporated herein by reference for all purposes.

[0114] In some embodiments, the strain sensor 3830 includes a bridge circuit formed by a pair of half-bridge circuits 3831, a set of electrical pads (e.g., contacts, taps, or pick-up points), and an electrical trace structure 3820. The bridge circuit (e.g., along the longitudinal axis A of the beam 3810) LO A distributed set of split bridge circuits) includes a set of strain gauges 3833 above (e.g., formed on) an electrically insulating layer. The bridge circuit 3831 has a uniform separation distance from the conductive layer. The electrical trace structure 3820 is electrically coupled between the sensor cable 3840 and the electrical pad. Therefore, the electrical trace structure 3820 can provide an input voltage to the bridge circuit and can transmit an output signal indicating strain to the sensor cable 3840.

[0115] In some embodiments, the electrical trace structure 3820 includes an input trace and one or more measurement traces (e.g., signal traces). The input trace is configured to deliver an input voltage (e.g., excitation voltage) from the sensor cable 3840 to one or more split half-bridge circuits 3831. The measurement trace is configured to deliver an output signal from the split half-bridge circuit 3831 to the sensor cable 3840. For example, for each bridge circuit, the first half-bridge circuit 3831 can deliver an output signal to the positive electrical trace of the sensor cable 3840, and the second half-bridge circuit 3831 can deliver an output signal to the negative electrical trace of the sensor cable 3840.

[0116] like Figure 13 As depicted, the sensor cable 3840 includes an intermediate portion 3841 between a proximal portion 3842 and a distal portion 3843. The sensor cable 3840 includes a longitudinal axis A extending between the proximal portion 3842 and the distal portion 3843. LO .like Figure 15B and Figure 18BAs depicted, an intermediate portion 3841 of the sensor cable 3840 includes a first set of electrical traces 3890. The first set of electrical traces 3890 may be communicatively coupled between a force sensor unit 3800 configured to measure a force affecting the instrument and a circuit board 3920 configured to receive an output from the force sensor unit 3800. The first set of electrical traces 3890 includes an electrical ground trace 3891. The electrical ground trace may electrically ground the force sensor unit 3800 to the circuit board 3920. In some embodiments, the electrical ground trace is electrically coupled to the beam 3810. In some embodiments, the force sensor unit 3800 may be electrically grounded to the circuit board via a drive cable, as described in U.S. Provisional Patent Application No. 63 / 425,524, filed on November 15, 2022, the disclosure of which is incorporated herein by reference for all purposes. In some embodiments, the sensor cable 3840 includes an electrical shield 3844 that surrounds the intermediate portion 3841 of the sensor cable 3840 and is communicatively coupled to the electrical ground trace 3891. In some embodiments, the electrical shield 3844 extends between a proximal transition portion 3845 and a distal transition portion 3850 of the sensor cable 3840. The sensor cable 3840 may include any of the elements and features described herein with reference to the sensor cable 2840 or the sensor cable 1840.

[0117] In some embodiments, the sensor cable 3840 includes a first layer 3860 (e.g., Figure 16A and Figure 19A ), a proximal second layer 3870 ( Figure 19B ), and a distal second layer 3880 ( Figure 16B ). The first layer 3860 extends between a distal portion 3843 and a proximal portion 3842 of the sensor cable 3840. The first layer 3860 includes a proximal section 3861 within the proximal portion 3842 of the sensor cable 3840. The first layer 3860 also includes a distal section 3862 within the distal portion 3843 of the sensor cable 3840. In other words, the first layer 3860 extends along the entire sensor cable 3840.

[0118] In some embodiments, the proximal second layer 3870 extends parallel to the proximal section 3861 of the first layer 3860 within the proximal portion 3842 of the sensor cable 3840. Figure 18B Depicted is the proximal second layer 3870 extending parallel to the proximal section 3861 of the first layer 3860. However, for clarity, Figure 19A and Figure 19B depict separated layers, where Figure 19A depicts a portion of the first layer 3860, and Figure 19BDepicts the proximal second layer 3870. Similarly, in some embodiments, the distal second layer 3880 extends parallel to the distal section 3862 of the first layer 3860 within the distal portion 3843 of the sensor cable 3840. Figure 15B Depicts the distal second layer 3880 extending parallel to the distal section 3862 of the first layer 3860. However, for clarity, Figure 16A and Figure 16B Depicts separate layers, where Figure 16A Depicts a portion of the first layer 3860, and Figure 16B Depicts the distal second layer 3880. In some embodiments, the middle portion 3841 of the sensor cable 3840 does not have the proximal second layer 3870 and the distal second layer 3880. In such embodiments, the first set of electrical traces 3890 may extend through the middle portion 3841 of the sensor cable 3840 in a side-by-side planar configuration within the first layer 3860. In other words, neither the proximal second layer 3870 nor the distal second layer 3880 extends the entire length of the sensor cable 3840.

[0119] In some embodiments, the proximal section 3861 of the first layer 3860 includes a proximal coupling interface 3863. The proximal coupling interface 3863 includes a first set of conductive contacts 3864. In some embodiments, such as Figure 18A Depicted, the first set of conductive contacts 3864 are arranged along a contact axis A parallel to the longitudinal axis A of the sensor cable 3840 LO of the contact axis A C is arranged. In some embodiments, the proximal coupling interface 2863 is an anisotropic conductive film coupling. In some embodiments, the proximal coupling interface 2863 is a moisture-proof connector.

[0120] The proximal section 3861 of the first layer 3860 in the proximal portion 3842 of the sensor cable 3840 does not have the first set of electrical traces 3890. In other words, the proximal section 3861 does not contain any electrical traces and thus defines a width across the first layer 3860 (e.g., along the transverse axis A) between the first set of electrical traces 3890 in the first layer 3860 and the proximal coupling interface 3863 LA)An extended non-conductive region. However, the proximal second layer 3870 is coupled to the proximal section 3861 and includes a second set of electrical traces 3896. The second set of electrical traces 3896 is communicatively coupled between the conductive contacts 3864 of the proximal coupling interface 3863 of the first layer 3860 and the first set of electrical traces 3890. In other words, during operation, the output signal from the force sensor unit 3800 can be transmitted proximally along the first set of electrical traces 3890 within the first layer 3860 to the proximal transfer portion 3845, where the first set of electrical traces 3890 terminates, and the output signal can be transmitted via the proximal coupling interface 3863 to the second set of electrical traces 3896 and onto the circuit board 3920.

[0121] As Figure 18B depicted, the proximal transfer portion 3845 is positioned between the proximal portion 3842 and the intermediate portion 3841 of the sensor cable 3840. The proximal transfer portion 3845 includes a set of vias 3846 as described herein. The set of vias 3846 within the proximal transfer portion 3845 is configured to communicatively couple the first set of electrical traces 3890 in the first layer 3860 to the second set of electrical traces 3896 in the proximal second layer 3870 in the proximal portion 3842 of the sensor cable 3840. In some embodiments, the proximal transfer portion 3845 may facilitate the rearrangement of the electrical traces to establish a trace layout consistent with the layout of the electrical contacts on the circuit board.

[0122] As Figure 15A and Figure 18A depicted, in some embodiments, the sensor cable 3840 includes a first electrical insulation layer 3847, an electrical insulation substrate (not shown), and a second electrical insulation layer (not shown). The first electrical insulation layer 3847 is over the distal section 3862 of the first layer 3860 and the intermediate portion 3841 of the sensor cable 3840 (as Figures 10A to 10B shown). The first electrical insulation layer 3847 is not present in the proximal section 3861 of the first layer 3860. In other words, since the first set of electrical traces 3890 terminates in the proximal transfer portion 3845 such that the proximal section 3861 of the first layer 3860 does not contain electrical traces, an electrically insulating proximal section 3861 is not needed. Thus, the first electrical insulation layer 3847 can terminate at the junction of the proximal transfer portion 3845 and the proximal portion 3842 of the sensor cable 3840, as indicated by the termination line T LThe indicated junction. By prohibiting the first electrical insulating layer 3847 from extending onto the proximal section 3861, the proximal section 3861 can remain in a neutral orientation when the proximal coupling interface 3863 is coupled to the circuit board 3920. In other words, the absence of the first electrical insulating layer 3847 on the proximal section 3861 obviates the need to bend or deform the first layer 3860 to bring a set of conductive contacts 3864 into contact with the circuit board 3920. Since the thickness of the first electrical insulating layer 3847 is absent between the proximal section 3861 and the circuit board, the planar nature of the proximal section 3861 can be maintained, and the separating forces otherwise generated by bending / flexing between the various layers of the sensor cable 3840 are reduced or eliminated. Similarly stated, the proximal section 3861 is coupled flush to the surface of the circuit board without any residual resilience that might exist if there were a step or discontinuity between the proximal section 3861 and the circuit board. This in turn reduces or eliminates delamination of the sensor cable 3840 when coupled to the circuit board, thus facilitating post-processing of the instrument.

[0123] Referring again to Figures 15B to 16B , in some embodiments, the sensor cable includes a distal transfer portion 3850. The distal transfer portion 3850 is positioned between the intermediate portion 3841 and the distal portion 3843 of the sensor cable 3840. The distal transfer portion 3850 includes a set of vias 3846. Accordingly, each via 3846 is an electrical connection between a first portion of a first set of electrical traces 3890 in the first layer 3860 and a third set of electrical traces 3897 in the distal second layer 3880.

[0124] In some embodiments, the distal section 3862 of the first layer 3860 in the distal portion 3843 of the sensor cable 3840 defines a distal coupling interface 3867. The distal coupling interface 3867 includes a second set of conductive contacts 3868 coupled to the force sensor unit 3800 as depicted in Figure 14 . As depicted in Figure 16A , a second portion 3895 of the first set of electrical traces 3890 is communicatively coupled to the distal coupling interface 3867 in the first layer 3860 in the distal portion 3843. Compared to the proximal section 3861, the distal section 3862 includes electrical traces and is thus covered with the first electrical insulating layer 3847. The third set of electrical traces 3897 in the distal second layer 3880 is coupled to the distal coupling interface 3867. In some embodiments, the distal coupling interface 3867 is an anisotropic conductive film coupling. In some embodiments, the distal coupling interface 3867 is a moisture-proof connector. In some embodiments, the distal coupling interface 3867 can mechanically couple and electrically couple the sensor cable to the force sensor unit (e.g., via ACF).

[0125] In some embodiments, under the condition that the second set of conductive contacts 3868 is electrically coupled to the force sensor unit 3800 as depicted in Figure 14 , the distal coupling interface 3867 is configured to be positioned orthogonal to the remainder of the distal portion 3843 of the sensor cable 3840. In other words, under the condition that the distal coupling interface 3867 is mechanically coupled to the force sensor unit 3800, the distal coupling interface 3867 is configured to be folded relative to the remainder of the distal portion 3843 of the sensor cable 3840. Thus, under the condition that the distal coupling interface 3867 is mechanically coupled to the force sensor unit 3800, the distal coupling interface 3867 can extend along a portion of the side surface 3812 of the beam 3810 and be separated from the side surface 3812 by the strain sensor 3830. Under the same condition, the remainder of the distal portion 3843 of the sensor cable 3840 can extend along the second surface of the beam 3810. For example, in some embodiments, the remainder of the distal portion 3843 can be mechanically coupled to the second surface of the beam 3810 that is orthogonal to the side surface 3812 as depicted in Figure 14 . In some embodiments, the remainder of the distal portion 3843 can be mechanically coupled to the second surface of the beam 3810 that is substantially parallel to the side surface 3812. In other words, the distal coupling interface can be configured to be folded and coupled to the force sensor unit 3800 on the first surface of the beam, while the remainder of the distal portion 3843 is mechanically coupled to the second surface of the beam 3810 that is orthogonal to the first surface. Referring to Figure 14 , the distal coupling interface 3867 can be pre-folded (e.g., folded before being coupled to the force sensor unit and / or during the manufacture of the sensor cable). In some embodiments, the size of the pre-fold corresponds to the angle between the first surface of the beam 3810 and the second surface of the beam 3810. It should be understood that forming the distal coupling interface 3867 with a pre-fold relative to the remainder of the distal portion 3843 of the sensor cable 3840 can facilitate the retention of the mechanical coupling between the distal coupling interface 3867 and the force sensor unit 3800.

[0126] In some embodiments, the linear arrangement of the second set of conductive contacts of the distal coupling interface 3867 establishes an initial configuration of the third set of electrical traces 3897 and the second portion 3895 of the first set of electrical traces 3890. For example, in some embodiments, the positive trace 3892 is positioned within the distal section 3862 of the first layer 3860. The negative trace 3893 and the electrical ground trace 3891 are positioned within the distal second layer 3880. In some embodiments, the third set of electrical traces 3897 and the second portion 3895 of the first set of electrical traces 3890 are rearranged within the distal transfer portion 3850. This rearrangement establishes all of the electrical traces of the first set of electrical traces 3890 in a side-by-side planar configuration passing through the middle portion 3841 of the sensor cable 3840 within the first layer 3860. In other words, the distal transfer portion 3850 facilitates the transition between a first arrangement of the electrical traces in the distal portion 3843 and a second arrangement in the middle portion 3841. For example, in some embodiments, the positive trace may be arranged in one portion of the sensor cable 3840 while the negative trace is arranged in another portion of the sensor cable 3840, with the electrical ground trace 3891 disposed therebetween. Alternatively, the positive and negative traces of the first set of electrical traces 3890 may be arranged in multiple positive-negative pairings as described herein.

[0127] Referring again to Figures 14 to 15B , in some embodiments, the sensor cable 3840 includes a balance portion 3853. The balance portion 3853 may extend distally from the distal portion 3843 of the sensor cable 3840. The balance portion 3853 may have a stiffness corresponding to (e.g., substantially equal to) the stiffness of the distal portion 3843 of the sensor cable 3840, but does not include any electrical traces. The balance portion 3853 may facilitate a uniform increase in the stiffness of the beam 3810 resulting from the coupling of the distal portion 3843 to the second face 3814 of the beam 3810. In other words, the balance portion may mitigate the effects of local stiffness concentration that may result from the coupling of the distal portion 3843 to the beam 3810. Similarly, as Figure 15A depicted, in some embodiments, the sensor cable 3840 may include a stiffness balance tab 3854. The stiffness balance tab 3854 may be coupled to a third face (not shown) of the beam 3810. The stiffness balance tab 3854 may have a stiffness corresponding to the stiffness of the strain sensor 3830 and does not have any electrical traces. In additional embodiments, the stiffness balance tab 3054 may extend onto a fourth face (not shown) of the beam 3810 such that the increase in beam stiffness caused by the components coupled thereto is uniform about the neutral axis of the beam 3810.

[0128] Figure 20A and Figure 20B are Figure 14Diagrammatic illustration of the configuration of the strain sensor 3830 depicted, showing eight half-bridge circuits 3831A to 3831H having a set of strain gauges 3833 (R1 to R 16 ) in four full-bridge circuit configurations. The eight half-bridge circuits 3831 include a first half-bridge circuit 3831A, a second half-bridge circuit 3831B, a third half-bridge circuit 3831C, a fourth half-bridge circuit 3831D, a fifth half-bridge circuit 3831E, a sixth half-bridge circuit 3831F, a seventh half-bridge circuit 3831G, and an eighth half-bridge circuit 3831H. To detect strain, an input voltage (e.g., a positive input voltage V P and a negative input voltage V N ) is provided to the eight half-bridge circuits 3831A to 3831H, and then the output voltage (e.g., V A , V B , V C , V D , V E , V F , V G , and V H (V A to V H )) can be measured for each of the eight half-bridge circuits 3831A to 3831H. The output voltages (V A to V H ) can be used by a controller in various combinations to determine the magnitude of the force affecting the instrument based on the sensed strain.

[0129] As Figure 20A depicted, in some embodiments, the first half-bridge circuit 3831A and the third half-bridge circuit 3831C are arranged as a primary distal bridge circuit combination 3832, while the second half-bridge circuit 3831B and the fourth half-bridge circuit 3831D are arranged as a primary proximal bridge circuit combination 3834. Additionally, in some embodiments, the fifth half-bridge circuit 3831E and the seventh half-bridge circuit 3831G are arranged as a secondary distal bridge circuit combination 3836, while the sixth half-bridge circuit 3831F and the eighth half-bridge circuit 3831H are arranged as a secondary proximal bridge circuit combination 3838. The output of the secondary distal bridge circuit combination 3836 is redundant with respect to the corresponding output of the primary distal bridge circuit combination 3832. Similarly, the output of the secondary proximal bridge circuit combination 3838 is redundant with respect to the corresponding output of the primary proximal bridge circuit combination 3834. In other words, in the absence of sensor failures, the outputs of the secondary distal bridge circuit combination 3836 and the secondary proximal bridge circuit combination 3838 are equal to the outputs of the primary distal bridge circuit combination 3832 and the primary proximal bridge circuit combination 3834.

[0130] As Figure 20AAs depicted, the first half-bridge circuit 3831A may include a third strain gauge resistor (R3) and a fourth strain gauge resistor (R4). The third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) may be positioned on opposite sides of the beam central axis A CL ( Figure 14 )(e.g., on a longitudinal axis A that is laterally centered on the side surface 3812 of the beam 3810 LO ) and equidistant from the central axis. For example, the third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) may be positioned equidistantly between the beam central axis A CL and the side edges of the surface to which they are mounted. In some embodiments, the third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) may be positioned at the same proximal location along the beam central axis A CL . In some embodiments, both the third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) are strain gauge resistors of the same type (e.g., both are tensile strain gauge resistors).

[0131] As Figure 20A further depicted, the third half-bridge circuit 3831C may include a seventh strain gauge resistor (R7) and an eighth strain gauge resistor (R8). The seventh strain gauge resistor (R7) and the eighth strain gauge resistor (R8) are positioned axially aligned with the beam central axis A CL . In some embodiments, a portion of the eighth strain gauge resistor (R8) is axially positioned between portions of the seventh strain gauge resistor (R7), and a portion of the seventh strain gauge resistor (R7) is axially positioned between portions of the eighth strain gauge resistor (R8). In some embodiments, one of the seventh strain gauge resistor (R7) and the eighth strain gauge resistor (R8) is a tensile strain gauge resistor and the other is a compressive strain gauge resistor.

[0132] As Figure 20A depicted, the second half-bridge circuit 3831B may include a first strain gauge resistor (R1) and a second strain gauge resistor (R2). The first strain gauge resistor (R1) and the second strain gauge resistor (R2) may be positioned on opposite sides of the beam central axis A CL and equidistant from the central axis. For example, the first strain gauge resistor (R1) and the second strain gauge resistor (R2) may be positioned equidistantly between the beam central axis A CL and the side edges of the surface to which they are mounted. In some embodiments, the first strain gauge resistor R1 and the second strain gauge resistor (R2) may be along the beam central axis A CLLocated at the same proximal location. In some embodiments, both the first strain gauge resistor (R1) and the second strain gauge resistor (R2) are the same type of strain gauge resistor (e.g., both are tensile strain gauge resistors).

[0133] As Figure 20A Further depicted, the fourth half-bridge circuit 3831D may include a fifth strain gauge resistor (R5) and a sixth strain gauge resistor (R6). The fifth strain gauge resistor (R5) and the sixth strain gauge resistor (R6) are positioned axially aligned with the beam central axis A CL Axially aligned. In some embodiments, a portion of the sixth strain gauge resistor (R6) is axially positioned between portions of the fifth strain gauge resistor (R5), and a portion of the fifth strain gauge resistor (R5) is axially positioned between portions of the sixth strain gauge resistor (R6). One of the fifth strain gauge resistor (R5) and the sixth strain gauge resistor (R6) is a tensile strain gauge resistor, while the other is a compressive strain gauge resistor.

[0134] Referring again to Figure 20A , as depicted, the fifth half-bridge circuit 3831E may include an eleventh strain gauge resistor (R 11 ) and a twelfth strain gauge resistor (R 12 ). The eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) may be positioned on opposite sides of the beam central axis A CL and equidistant from the central axis. For example, the eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) may be positioned equidistantly between the beam central axis A CL and the side edges of the surface to which they are mounted. In some embodiments, the eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) may be located along the beam central axis A CL at the same proximal location. In some embodiments, both the eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) are the same type of strain gauge resistor (e.g., both are tensile strain gauge resistors). The fifth half-bridge circuit 3831E is positioned distally relative to the first half-bridge circuit 3831A.

[0135] As Figure 20A Further depicted, the seventh half-bridge circuit 3831G may include a fifteenth strain gauge resistor (R 15 ) and a sixteenth strain gauge resistor (R16 ). The fifteenth strain gauge resistor (R 15 ) and the sixteenth strain gauge resistor (R 16 ) are positioned axially aligned with the beam central axis A CL . In some embodiments, a portion of the fifteenth strain gauge resistor (R 15 ) is axially positioned between portions of the sixteenth strain gauge resistor (R 16 ), and a portion of the sixteenth strain gauge resistor (R 16 ) is axially positioned between portions of the fifteenth strain gauge resistor (R 15 ). One of the fifteenth strain gauge resistor (R 15 ) and the sixteenth strain gauge resistor (R 16 ) is a tensile strain gauge resistor and the other is a compressive strain gauge resistor. The seventh half-bridge circuit 3831G is positioned distally relative to the third half-bridge circuit 3831C.

[0136] As Figure 20A depicted, the sixth half-bridge circuit 3831F may include a ninth strain gauge resistor (R9) and a tenth strain gauge resistor (R 10 ). The ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) may be positioned on opposite sides of the beam central axis A CL and equidistant from the central axis. For example, the ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) may be positioned equidistantly between the beam central axis A CL and the side edges of the surface to which they are mounted. In some embodiments, the ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) may be positioned at the same proximal location along the beam central axis A CL . In some embodiments, both the ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) are strain gauge resistors of the same type (e.g., both are tensile strain gauge resistors). The sixth half-bridge circuit 3831F is positioned distally relative to the second half-bridge circuit 3831B.

[0137] As Figure 20A further depicted, the eighth half-bridge circuit 3831H may include a thirteenth strain gauge resistor (R 13 ) and a fourteenth strain gauge resistor (R 14 ). The thirteenth strain gauge resistor (R 13 ) and the fourteenth strain gauge resistor (R 14 ) are positioned axially aligned with the beam central axis A CLAxial alignment. In some embodiments, a portion of a thirteenth strain gauge resistor (R 13 ) is axially positioned between portions of a fourteenth strain gauge resistor (R 14 ), and a portion of the fourteenth strain gauge resistor (R 14 ) is axially positioned between portions of the thirteenth strain gauge resistor (R 13 ). One of the thirteenth strain gauge resistor (R 13 ) and the fourteenth strain gauge resistor (R 14 ) is a tensile strain gauge resistor, and the other is a compressive strain gauge resistor. The eighth half-bridge circuit 3831H is positioned distally relative to the fourth half-bridge circuit 3831D.

[0138] As Figure 20B and Figure 20C depicted, in some embodiments, the strain sensor includes four full-bridge circuit arrangements, where each full-bridge circuit includes two half-bridge circuits, for a total of eight half-bridge circuits. Compared to the arrangement Figure 20A depicted, the corresponding half-bridge circuits of each full-bridge circuit are located on opposite end portions of the strain sensor (e.g., on the distal portion and the proximal portion). The first half-bridge circuit 3831A is positioned at the distal portion 3815 of the beam 3810, while the second half-bridge circuit 3831B is positioned at the proximal portion 3813 of the beam 3810. Sensor cables 2840, pads 3839, and / or anisotropic conductive films (ACFs) may extend or be disposed therebetween (e.g., separating the first half-bridge and the second half-bridge, the distal portion half-bridge and the proximal portion half-bridge), as described in more detail below. The first half-bridge circuit 3831A and the second half-bridge circuit 3831B may be electrically coupled to form a first primary full-bridge circuit. The first primary full-bridge circuit may be configured to measure strain applied along a first axis. The first axis may be, for example, transverse to the side 3812 of the beam 3810 (e.g., in the direction of the transverse axis A LA ). In some embodiments, the first axis is the X axis, and the strain gauges of the first primary full-bridge circuit may each be tensile strain gauge resistors (e.g., measuring strain along the X axis). In some embodiments, the tensile strain gauge resistors described herein may have elongated portions that are parallel-aligned and end-to-end coupled to form a meandering or serpentine configuration. The elongated portions of the tensile gauge resistors may extend or be aligned parallel to the longitudinal axis A LO .

[0139] As depicted, the first half-bridge circuit 3831A may include a first strain gauge resistor (R1) and a second strain gauge resistor (R2). The first strain gauge resistor (R1) and the second strain gauge resistor (R2) may be positioned on the beam central axis A CLOn opposite sides thereof and equidistant from the central axis. For example, the first strain gauge resistor (R1) and the second strain gauge resistor (R2) may be positioned equidistantly from the beam central axis A CL Between the side edges of the surface to which they are mounted. In some embodiments, the first strain gauge resistor (R1) and the second strain gauge resistor (R2) may be along the beam central axis A CL Positioned at the same distal location. In some embodiments, both the first strain gauge resistor (R1) and the second strain gauge resistor (R2) are strain gauge resistors of the same type (e.g., both are tensile strain gauge resistors).

[0140] As further depicted, the second half-bridge circuit 3831B may include a third strain gauge resistor (R3) and a fourth strain gauge resistor (R4). The third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) may be positioned on opposite sides of the beam central axis A CL (e.g., the longitudinal axis A that is laterally centered on the side surface 3812 of the beam 3810 LO ) and equidistant from the central axis. For example, the third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) may be positioned equidistantly from the beam central axis A CL Between the side edges of the surface to which they are mounted. In some embodiments, the third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) may be along the beam central axis A CL Positioned at the same proximal location. In some embodiments, both the third strain gauge resistor (R3) and the fourth strain gauge resistor (R4) are strain gauge resistors of the same type (e.g., both are tensile strain gauge resistors).

[0141] As Figure 20B And Figure 20CDepicted, in some embodiments, the third half-bridge circuit 3831C is positioned at the distal portion 3815 of the beam 3810, while the fourth half-bridge circuit 3831D is positioned at the proximal portion 3813 of the beam 3810. The third half-bridge circuit 3831C and the fourth half-bridge circuit 3831D can be electrically coupled to form a second primary full-bridge circuit. The second primary full-bridge circuit can be configured to measure the strain applied along a second axis orthogonal to the first axis (e.g., measure the strain along the second axis). The second axis can be, for example, perpendicular to the side surface 3812 of the beam 3810. In some embodiments, the second axis is the Y axis, and the strain gauges of the second primary full-bridge circuit can be a combination of a tensile strain gauge resistor and a compressive strain gauge resistor. As discussed above with respect to the first primary full-bridge circuit, the tensile strain gauge resistors described herein can have elongated portions that are parallel-aligned and end-to-end coupled to form a meandering or serpentine configuration. The elongated portions of the extensometer resistor can be parallel to the longitudinal axis A LO extend or be aligned. Similarly, the compressive strain gauge resistors described herein can also have elongated portions that are parallel-aligned and end-to-end coupled to form a meandering or serpentine configuration. However, the elongated portions of the compressometer resistors described herein can be transverse to the longitudinal axis A LO (e.g., parallel to the transverse axis A LA ) extend or be aligned.

[0142] As depicted, the third half-bridge circuit 3831C can include a fifth strain gauge resistor (R5) and a sixth strain gauge resistor (R6). The fifth strain gauge resistor (R5) and the sixth strain gauge resistor (R6) are positioned axially aligned with the beam center axis A CL In some embodiments, a portion of the sixth strain gauge resistor (R6) is axially positioned between portions of the fifth strain gauge resistor (R5), and / or a portion of the fifth strain gauge resistor (R5) is axially positioned between portions of the sixth strain gauge resistor (R6). In some embodiments, one of the fifth strain gauge resistor (R5) and the sixth strain gauge resistor (R6) is a tensile strain gauge resistor, while the other is a compressive strain gauge resistor.

[0143] As further depicted, the fourth half-bridge circuit 3831D can include a seventh strain gauge resistor (R7) and an eighth strain gauge resistor (R8). The seventh strain gauge resistor (R7) and the eighth strain gauge resistor (R8) are positioned axially aligned with the beam center axis A CLAxial alignment. In some embodiments, a portion of the eighth strain gauge resistor (R8) is axially positioned between portions of the seventh strain gauge resistor (R7), and / or a portion of the seventh strain gauge resistor (R7) is axially positioned between portions of the eighth strain gauge resistor (R8). In some embodiments, one of the seventh strain gauge resistor (R7) and the eighth strain gauge resistor (R8) is a tensile strain gauge resistor and the other is a compressive strain gauge resistor.

[0144] As Figure 20B and Figure 20C depicted, in some embodiments, the fifth half-bridge circuit 3831E is positioned at the distal portion 3815 of the beam 3810, while the sixth half-bridge circuit 3831F is positioned at the proximal portion 3813 of the beam 3810. The fifth half-bridge circuit 3831E and the sixth half-bridge circuit 3831F may be electrically coupled to form a first secondary full-bridge circuit. The first secondary full-bridge circuit may be configured to measure strain applied along a first axis. In some embodiments, the first secondary full-bridge circuits may each be tensile strain gauge resistors.

[0145] As depicted, the fifth half-bridge circuit 3831E may include a ninth strain gauge resistor (R9) and a tenth strain gauge resistor (R 10 ). The ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) may be positioned on opposite sides of the beam center axis A CL and equidistant from the center axis. For example, the ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) may be positioned equidistantly between the beam center axis A CL and the side edges of the surface to which they are mounted. In some embodiments, the ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) may be positioned at the same distal location along the beam center axis A CL . In some embodiments, both the ninth strain gauge resistor (R9) and the tenth strain gauge resistor (R 10 ) are the same type of strain gauge resistor (e.g., both are tensile strain gauge resistors). The fifth half-bridge circuit 3831E may be longitudinally positioned between the first half-bridge circuit 3831A and the second half-bridge circuit 3831B (e.g., proximal with respect to the first half-bridge circuit 3831a and distal with respect to the second half-bridge circuit 3831B).

[0146] As further depicted, the sixth half-bridge circuit 3831F may include an eleventh strain gauge resistor (R 11 ) and a twelfth strain gauge resistor (R 12 ). The eleventh strain gauge resistor (R11 ) and the twelfth strain gauge resistor (R 12 ) may be positioned on opposite sides of the beam central axis A CL and equidistant from the central axis. For example, the eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) may be positioned equidistantly between the beam central axis A CL and the side edges of the surface to which they are mounted. In some embodiments, the eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) may be positioned at the same proximal location along the beam central axis A CL . In some embodiments, both the eleventh strain gauge resistor (R 11 ) and the twelfth strain gauge resistor (R 12 ) are strain gauge resistors of the same type (e.g., both are tensile strain gauge resistors). The sixth half-bridge circuit 3831F may be positioned proximally relative to the second half-bridge circuit 3831B.

[0147] As Figure 20B and Figure 20C depicted, in some embodiments, the seventh half-bridge circuit 3831G is positioned at the distal portion 3815 of the beam 3810, while the eighth half-bridge circuit 3831H is positioned at the proximal portion 3813 of the beam 3810. The seventh half-bridge circuit 3831G and the eighth half-bridge circuit 3831H may be electrically coupled to form a second secondary full-bridge circuit. The second secondary full-bridge circuit may be configured to measure the strain applied along the second axis. In some embodiments, the second secondary full-bridge circuit may be a combination of a tensile strain gauge resistor and a compressive strain gauge resistor.

[0148] As depicted, the seventh half-bridge circuit 3831G may include a thirteenth strain gauge resistor (R 13 ) and a fourteenth strain gauge resistor (R 14 ). The thirteenth strain gauge resistor (R 13 ) and the fourteenth strain gauge resistor (R 14 ) are positioned axially aligned with the beam central axis A CL . In some embodiments, a portion of the thirteenth strain gauge resistor (R 13 ) is axially positioned between portions of the fourteenth strain gauge resistor (R 14 ), and / or a portion of the fourteenth strain gauge resistor (R 14 ) is axially positioned between portions of the thirteenth strain gauge resistor (R 13 ). In some embodiments, the thirteenth strain gauge resistor (R 13) and the fourteenth strain gauge resistor (R 14 ) can be a tensile strain gauge resistor and the other can be a compressive strain gauge resistor. The seventh half-bridge circuit 3831G can be positioned distally relative to the fourth half-bridge circuit 3831D. In some embodiments, the seventh half-bridge circuit 3831G can be positioned proximally relative to the third half-bridge circuit 3831C.

[0149] As further depicted, the eighth half-bridge circuit 3831H can include a fifteenth strain gauge resistor (R 15 ) and a sixteenth strain gauge resistor (R 16 ). The fifteenth strain gauge resistor (R 15 ) and the sixteenth strain gauge resistor (R 16 ) are positioned axially aligned with the beam central axis A CL . In some embodiments, a portion of the fifteenth strain gauge resistor (R 15 ) is axially positioned between portions of the sixteenth strain gauge resistor (R 16 ), and / or a portion of the sixteenth strain gauge resistor (R 16 ) is axially positioned between portions of the fifteenth strain gauge resistor (R 15 ). In some embodiments, one of the fifteenth strain gauge resistor (R 15 ) and the sixteenth strain gauge resistor (R 16 ) is a tensile strain gauge resistor and the other is a compressive strain gauge resistor. The eighth half-bridge circuit 3831H can be positioned proximally relative to the third half-bridge circuit 3831C.

[0150] In some embodiments, the output of the first secondary full-bridge circuit can be redundant with respect to the corresponding output of the first primary full-bridge circuit. Similarly, the output of the second secondary full-bridge circuit can be redundant with respect to the corresponding output of the second primary full-bridge circuit. In other words, in the absence of sensor failures, the respective outputs of the first secondary full-bridge circuit and the second secondary full-bridge circuit are substantially equal to the respective outputs of the corresponding first primary full-bridge circuit and second primary full-bridge circuit.

[0151] As Figure 21 specifically shown, a schematic diagram of one embodiment of suitable components that can be included within the controller 1180 is shown. In some embodiments, the controller 1180 is positioned within components of the surgical system 1000 such as the user control unit 1100 and / or the optional auxiliary device unit 1150. However, the controller 1180 can also include a distributed computing system where at least one aspect of the controller 1180 is located at a different location from the rest of the components of the surgical system 1000. For example, at least a portion of the controller 1180 can be an online controller.

[0152] As depicted, controller 1180 includes one or more processors 1182 and associated memory devices 1184, which are configured to perform various computer-implemented functions (e.g., execute methods, steps, calculations, etc. as disclosed herein and store relevant data). Additionally, in some embodiments, controller 1180 includes a communication module 1186 to facilitate communication between controller 1180 and various components of the surgical system 1000.

[0153] As used herein, the term "processor" refers not only to integrated circuits included in a computer as referred to in the art, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits, and other programmable circuits. Additionally, memory device 1184 can generally include memory elements, including but not limited to computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), floppy disks, compact disk read-only memory (CD ROM), magneto-optical disks (MOD), digital versatile disks (DVD), and / or other suitable memory elements. Such memory device 1184 can generally be configured to store suitable computer-readable instructions that, when implemented by processor 1182, configure controller 1180 to perform various functions.

[0154] In some embodiments, controller 1180 includes a haptic feedback module 1196. The haptic feedback module 1196 can be configured to deliver haptic feedback to an operator based on input received from the force sensor unit 1800 of the instrument 1400. In some embodiments, the haptic feedback module 1196 can be a stand-alone module of controller 1180. However, in some embodiments, the haptic feedback module 1196 can be included within the memory device 1184.

[0155] The communication module 1186 can include a control input module 1188 that is configured to receive control input from an operator / surgeon S, such as via the input device 1116 of the user control unit 1100. The communication module can also include an indicator module 1192 that is configured to generate various indications to warn the operator.

[0156] The communication module 1186 may also include a sensor interface 1190 (e.g., one or more analog-to-digital converters) to allow signals transmitted from one or more sensors (e.g., strain sensors of the force sensor unit 1800) to be converted into signals that can be understood and processed by the processor 1182. The sensors may be communicatively coupled to the communication module 1186 using any suitable means. For example, the sensors may be coupled to the communication module 1186 via a wired connection and / or via a wireless connection, such as by using any suitable wireless communication protocol known in the art to couple to the communication module 1186. Additionally, in some embodiments, the communication module 1186 includes a device control module 1814 that is configured to modify the operating state of the instrument 1400 (and / or any of the instruments described herein). Thus, the communication module is communicatively coupled to the manipulator unit 1200 and / or the instrument 1400. For example, the communication module 1186 may transmit to the manipulator unit 1200 and / or the instrument 1400 an excitation voltage for the strain sensor, a handshake and / or excitation voltage for the position sensor (e.g., for detecting the position of a designated portion relative to the cannula), cautery control, a position setpoint, and / or an end effector operation setpoint (e.g., a grasp, cut, and / or other similar operation performed by the end effector).

[0157] Although the various embodiments have been described above, it should be understood that these embodiments are presented by way of example only and not limitation. In cases where the above methods and / or diagrams indicate a particular order of occurrence of particular events and / or process patterns, the order of the particular events and / or operations may be modified. While the embodiments have been specifically shown and described, it should be understood that various changes in form and detail may be made.

[0158] For example, any of the instruments described herein (and components thereof) are optional parts of a surgical assembly that performs minimally invasive surgical procedures and may include a manipulator unit, a series of motion linkages, a set of cannulas, etc. Thus, any of the instruments described herein may be used in any suitable surgical system, such as the MIRS system 1000 shown and described above. Additionally, any of the instruments shown and described herein may be used to manipulate target tissue during a surgical procedure. Such target tissue may be cancer cells, tumor cells, lesions, vascular occlusions, thrombi, stones, uterine fibroids, bone metastases, adenomyosis, or any other body tissue. The examples of target tissue presented are not an exhaustive list. Additionally, the target structure may also include artificial substances (or non-tissues) that are in or associated with the body, such as, for example, a stent, a portion of an artificial tube, a fastener in the body, etc.

[0159] For example, any of the components of the surgical instrument described herein can be constructed of any material such as medical grade stainless steel, nickel alloy, titanium alloy, etc. Additionally, any of the linkages, tool members, beams, shafts, cables, or other components described herein can be constructed of multiple pieces that are later joined together. For example, in some embodiments, a linkage can be constructed by joining separately constructed components together. However, in other embodiments, any of the linkages, tool members, beams, shafts, cables, or components described herein can be constructed as a unitary structure.

[0160] Although various embodiments are described as having combinations of specific features and / or components, other embodiments having any combination of features and / or components from any of the embodiments discussed above are also possible. Aspects have been described in the general context of medical devices and, more particularly, surgical instruments, but aspects of the invention are not necessarily limited to use in medical devices.

Claims

1. A force-sensing medical device, comprising: Proximal mechanical structure; Instrument shaft, the instrument shaft being coupled to the proximal mechanical structure; Force sensor unit, the force sensor unit being coupled to a distal portion of the instrument shaft; Circuit board, the circuit board being coupled to the proximal mechanical structure and configured to receive an output from the force sensor unit; And Sensor cable, the sensor cable having an intermediate portion and a first plurality of electrical traces, communicatively coupled between the force sensor unit and the circuit board; Wherein, the first plurality of electrical traces includes an electrical ground trace; Wherein, the sensor cable includes an electrical shield surrounding the intermediate portion of the sensor cable; and Wherein, the electrical shield is communicatively coupled to the electrical ground trace.

2. The medical device according to claim 1, wherein: The sensor cable includes a proximal portion, a distal portion, a first layer, a proximal second layer, and a distal second layer separated from the proximal second layer; The first layer extends between the distal portion and the proximal portion of the sensor cable, and includes a proximal section and a distal section; The proximal second layer extends parallel to the proximal section of the first layer; The distal second layer extends parallel to the distal section of the first layer; The proximal section of the first layer includes a proximal coupling interface, and the proximal coupling interface includes a first plurality of conductive contacts; The proximal section of the first layer in the proximal portion of the sensor cable does not have the first plurality of electrical traces; and The proximal second layer is coupled to the proximal section and includes a second plurality of electrical traces communicatively coupled to the plurality of conductive contacts.

3. The medical device according to claim 2, wherein: The intermediate portion of the sensor cable does not have the proximal second layer and the distal second layer; and The first plurality of electrical traces extend through the intermediate portion of the sensor cable in a side-by-side planar configuration within the first layer.

4. The medical device according to claim 3, wherein: The sensor cable includes a proximal transition portion between the proximal portion and the intermediate portion of the sensor cable; and The proximal transition portion includes a plurality of through holes configured to communicatively couple the first plurality of electrical traces in the first layer in the intermediate portion to the second plurality of electrical traces in the proximal second layer.

5. The medical device according to claim 3, wherein: The first plurality of electrical traces includes a plurality of positive traces and a plurality of negative traces in the intermediate portion of the sensor cable; Each positive trace of the plurality of positive traces has a first cross-sectional area; Each negative trace of the plurality of negative traces has a second cross-sectional area; And The first cross-sectional area is less than the second cross-sectional area.

6. The medical device according to claim 5, wherein: A first maximum resistance limit determines a minimum first cross-sectional area of the first cross-sectional area of the plurality of positive traces; And A second maximum resistance limit determines a minimum second cross-sectional area of the second cross-sectional area of the plurality of negative traces.

7. The medical device according to claim 5, wherein: A maximum sensor cable width defines a maximum combined cross-sectional area of each of the plurality of positive traces and the plurality of negative traces in the intermediate portion of the sensor cable; And The maximum sensor cable width is at least partially defined by a channel clearance of the instrument shaft.

8. The medical device according to claim 2, wherein: The sensor cable includes a first electrical insulation layer, an electrical insulation substrate, and a second electrical insulation layer; The first electrical insulation layer is on the distal section of the first layer and the middle portion of the sensor cable; The first electrical insulation layer is not present in the proximal section of the first layer; The electrical insulation substrate extends between the distal portion and the proximal portion of the sensor cable; And The second electrical insulation layer is on the distal second layer, the middle portion of the sensor cable, and the proximal second layer.

9. The medical device according to claim 2, wherein: The sensor cable includes a longitudinal axis extending between the proximal portion and the distal portion; and The first plurality of conductive contacts are arranged along a contact axis parallel to the longitudinal axis of the sensor cable.

10. The medical device according to claim 2, wherein: The proximal coupling interface is an anisotropic conductive film coupling.

11. The medical device according to claim 2, wherein: The sensor cable includes a distal transfer portion between the middle portion and the distal portion of the sensor cable; and The distal transfer portion includes a plurality of through-holes configured to communicatively couple a first portion of the first plurality of electrical traces in the middle portion to a third plurality of electrical traces in the distal second layer.

12. The medical device according to claim 11, wherein: The distal section of the first layer in the distal portion of the sensor cable includes a distal coupling interface having a second plurality of conductive contacts coupled to the force sensor unit; A second portion of the first plurality of electrical traces is communicatively coupled to the distal coupling interface in the first layer; The third plurality of electrical traces in the distal second layer are coupled to the distal coupling interface; And The linear arrangement of the second plurality of conductive contacts establishes an initial configuration of the third plurality of electrical traces and the second portion of the first plurality of electrical traces.

13. The medical device according to claim 12, wherein: The third plurality of electrical traces and the second portion of the first plurality of electrical traces are rearranged within the distal transfer portion to establish all of the electrical traces of the first plurality of electrical traces in a side-by-side planar configuration passing through the middle portion of the sensor cable within the first layer.

14. The medical device according to claim 13, wherein: The middle portion of the sensor cable includes a first lateral side region and a second lateral side region separated by the electrical ground trace; The first plurality of electrical traces includes a plurality of positive traces and a plurality of negative traces in the middle portion of the sensor cable; and The side-by-side planar configuration includes the plurality of positive traces positioned in the first lateral side region and the plurality of negative traces positioned in the second lateral side region.

15. The medical device according to claim 13, wherein: The first plurality of electrical traces includes one or more positive traces and one or more negative traces in the middle portion of the sensor cable; and The side-by-side planar configuration includes the one or more positive traces and the one or more negative traces arranged in a positive-negative pairing.

16. The medical device according to claim 12, wherein: The medical device further includes a beam, and the beam includes a first face and a second face; The force sensor unit includes a strain sensor on the first face of the beam; The distal coupling interface is coupled to the strain sensor on the first face of the beam; The distal portion of the sensor cable is coupled to the second face of the beam adjacent to the first face of the beam; The distal coupling interface is pre-folded relative to the remainder of the distal portion to align the distal coupling interface with the first face of the beam; and The size of the pre-fold corresponds to the angle between the first face of the beam and the second face of the beam.

17. The medical device according to claim 2, wherein: The sensor cable includes a balance portion extending distally from the distal portion of the sensor cable; The balance portion has a stiffness corresponding to the stiffness of the distal portion of the sensor cable; and The balance portion has no electrical traces.

18. The medical device according to claim 2, wherein: The medical device further includes a beam, and the beam includes a first face, a second face, and a third face; The force sensor unit includes a strain sensor on the first face of the beam; The distal portion of the sensor cable is coupled to the second face of the beam adjacent to the first face of the beam; The sensor cable includes a stiffness balance tab coupled to the third face of the beam; The stiffness balance tab has a stiffness corresponding to one of the stiffness of the strain sensor or the stiffness of the distal portion of the sensor cable; and The stiffness balance tab has no electrical traces.

19. The medical device according to claim 18, wherein: The strain sensor includes eight bridge circuits arranged as four bridge circuit combinations; and Each of the eight bridge circuits includes two strain gauges.

20. The medical device according to claim 2, wherein: The sensor cable has a first longitudinal length; The first layer has a second longitudinal length; The proximal second layer has a third longitudinal length; The distal second layer has a fourth longitudinal length; The second longitudinal length is equal to the first longitudinal length; and The combination of the third longitudinal length plus the fourth longitudinal length is less than the second longitudinal length.

21. The medical device according to claim 1, wherein: The medical device includes an end effector and a wrist assembly; The end effector is coupled to the force sensor unit via the wrist assembly; and The medical device is configured to be operably coupled to a surgical system.

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