Dual multi-axis force and torque sensor in a robotic surgical system

Abstract

A robotic system for minimally invasive surgery includes a robotic arm with robotic F / T sensors and surgical instruments attached thereto. The surgical instruments are positioned within a patient's body cavity via a cannula in which a cannula F / T sensor is integrated. The output of the cannula F / T sensor is subtracted from the output of the robotic F / T sensor (and vice versa) to eliminate the influence of force or torque between the cannula and the patient's skin, obtaining only the force or torque applied to the surgical instruments. To perform this subtraction, the reference frames of the two F / T sensors are first aligned. For example, the position of the surgical instrument tip can be measured or estimated, and the corrected force or torque can be similarly converted to the reference frame of the surgical instrument tip.

Description

Technical Field

[0001] This disclosure generally relates to robotic surgical instruments, and more particularly to the use of two multi-axis force and torque sensors to determine the force and / or torque applied through a cannula to the tip of a surgical instrument positioned in a patient's body cavity. Background Technology

[0002] Force and / or torque (F / T) sensors are well-known in the field of robotics. F / T sensors measure the forces and torques acting on a robotic arm and provide this data to the robot's control system. F / T feedback and monitoring are crucial for many robotic operations. For example, in force-controlled operations such as material removal (drilling, grinding, polishing, etc.), F / T sensors attached to the robotic arm sense the actual force applied to the workpiece by the robotic tool and control the robotic arm (or compliance structure) to maintain the contact force at or below a set point. Examples of multi-axis F / T sensors and F / T solutions include those described in U.S. Patent Nos. 10,422,707; 10,067,019; 11,892,364; 11,747,224; 11,491,663; 11,085,838; and those described in U.S. Patent Application No. 2023 / 0049155, all of which are assigned to the assignee of this disclosure and are incorporated herein by reference in their entirety.

[0003] The use of robots in medical and veterinary surgery has increased dramatically. Robotics has enabled “minimally invasive” surgery, in which only one or a few small incisions are made in the patient’s body to insert robotic tools into the cavity. This differs significantly from traditional surgery, where a sufficiently large opening must be made in the patient’s body to allow the surgeon to insert his or her hand holding the instrument. Laparoscopy is a popular form of minimally invasive surgery where a light source and camera are inserted into the cavity through a small incision. The camera sends images of the patient’s body to a monitor on which the surgeon is monitoring. Other surgical instruments, such as scalpels and forceps, are inserted through the same or different incisions and can be manipulated directly or remotely by the surgeon to perform the surgery within the cavity. This minimally invasive surgery can be performed manually; with the aid of some robotic surgical tools; or entirely robotic, where the surgeon controls a robotic arm that physically manipulates the surgical tools inside the patient’s body. In the latter case, with sufficiently high-speed and reliable data communication, the surgeon can be far from the patient, in a separate room or even in another country.

[0004] Surgeons naturally control the force with which they use surgical instruments. Whenever a surgeon's hand is not directly controlling the instrument, force / torque sensors are needed to determine these applied forces to prevent tissue damage and ensure proper manipulation. For example, force and / or torque information from force / torque sensors on robotic surgical instruments can be provided to the tactile feedback system of a minimally invasive surgical system. By integrating force and torque sensors into the robotic instrument, the system can simulate touch, transmitting tactile information back to the surgeon. This provides an accurate "feel" of the actuators used by the surgeon to control the robotic surgical instrument and offers the beneficial illusion that the surgeon is directly, rather than remotely, holding and controlling the surgical tools. This feedback is crucial for tasks requiring fine motor skills, such as suturing or dissecting tissue.

[0005] Furthermore, force and torque sensing is crucial for the development of advanced control algorithms in surgical robotics. These algorithms use data from sensors to adjust the movement of the robotic arm in real time, ensuring smooth and precise operation. For example, in surgeries such as retinal microsurgery, even slight movements can have significant consequences, and sensors help maintain stability and control. This technology not only improves surgical outcomes but also enhances the training of new surgeons by providing them with detailed feedback on their performance.

[0006] A major challenge in incorporating force / torque sensors into robotic surgical instruments is the miniaturization requirement of these sensors. Surgical instruments, especially those used in minimally invasive surgery, need to be extremely small to pass through tiny incisions. Integrating sensors capable of accurately measuring force and torque without compromising instrument size and function is a challenge.

[0007] Another challenge is ensuring the durability and reliability of these sensors in harsh surgical environments. Surgical instruments must withstand sterilization processes, which typically involve high temperatures and harsh chemicals. Sensors must be robust enough to maintain their accuracy and functionality after repeated sterilization. Furthermore, they need to be resistant to bodily fluids and other contaminants encountered during surgery.

[0008] A trocar is a medical device essential for minimally invasive surgery. A trocar typically comprises an occluder, a cannula, and a seal. The occluder is a pointed or blunt-tipped instrument that facilitates initial penetration of the body cavity. The cannula is a hollow tube that remains in place after the occluder is removed, providing a pathway for the insertion of other surgical instruments. The seal ensures that no air or fluid escapes from the body cavity during the procedure. In laparoscopic surgery, trocars allow surgeons to introduce cameras and other instruments into the patient's abdominal cavity without making large incisions, significantly reducing recovery time and the risk of complications.

[0009] Force sensing systems are known to be integrated into the housing of a cannula or inserted plug. Such systems detect force in one direction, along the longitudinal axis of the cannula / shunt and toward the patient. For example, the system can issue an indication (e.g., illuminating a green LED) if the applied force is below a predetermined threshold, and a different indication (e.g., illuminating a red LED) if the applied force exceeds the threshold. This type of force sensing system addresses situations where clinicians may attempt to use surgical instruments (e.g., sutures, forceps, etc.) within a body cavity at locations farther from the incision than the instrument's length.

[0010] It is also known to attach force-sensing elements (such as strain gauges) to the outer sleeve of the casing, near the point of insertion into the body wall. The strain gauge detects and measures the force applied to the outer wall of the outer sleeve in a direction typically transverse to the longitudinal dimension of the casing by contacting the body wall. Because the outer wall is not mechanically connected to the casing, the strain gauge is isolated from the instrument-casing interaction when the instrument is manipulated within the casing.

[0011] U.S. Provisional Patent Application Serial No. 63 / 742,115, entitled “Trocar with Multi-Axis Force and Torque Sensing,” filed January 6, 2025, and assigned to the assignee of this disclosure, describes the integration of a multi-axis force and torque sensor onto the cannula of a trocar, referred to herein as a trocar F / T sensor. The disclosure of this application is incorporated herein by reference in its entirety.

[0012] Neither traditional force-to-torque (F / T) sensors on robotic arms nor existing cannula F / T sensors provide data reflecting the actual forces and torques experienced at the distal end or tip of robotic surgical instruments. Both are externally positioned to record forces, such as those between the cannula and the patient's skin, that are not generated by contact between the robotic surgical instrument and tissue within the patient's body cavity—the F / T measurements of interest. Integrating F / T sensors directly onto surgical instruments is problematic due to the aforementioned size and reliability challenges, as well as the cost of replicating the F / T sensor instrument on every surgical instrument. Therefore, determining and reporting the actual forces and torques experienced at the distal end of surgical instruments is a significant challenge advancing minimally invasive surgical techniques.

[0013] The background section of this document is provided to place various aspects of this disclosure within a technical and operational context to assist those skilled in the art in understanding its scope and applicability. The methods described in the background section may be employed, but are not necessarily methods previously conceived or employed. Unless expressly stated otherwise, nothing herein should be considered prior art simply by incorporating it into the background section. Summary of the Invention

[0014] The following is a simplified summary of this disclosure to provide a basic understanding for those skilled in the art. This summary is not a broad overview of the disclosure, nor is it intended to identify key / essential elements of any aspect of the disclosure or to limit its scope. The sole purpose of this summary is to present some of the concepts disclosed herein in a simplified form as a prelude to the more detailed description that follows.

[0015] According to one or more aspects described and claimed herein, a robotic system for minimally invasive surgery includes a robotic arm with robotic F / T sensors and surgical instruments attached thereto. The surgical instruments are placed within a patient's body cavity via a cannula, in which a cannula F / T sensor is integrated. The output of the cannula F / T sensor is subtracted from the output of the robotic F / T sensor (and vice versa) to eliminate the influence of force and / or torque between the cannula and the patient's skin, resulting only in the force and / or torque applied to the surgical instruments. To perform this subtraction, the reference frames of the two F / T sensors are first aligned. For example, the position of the surgical instrument tip can be measured or estimated, and the corrected force and / or torque can be similarly converted to the reference frame of the surgical instrument tip.

[0016] One embodiment relates to a dual-multi-axis force and / or torque (F / T) sensor robotic system for minimally invasive surgery, robotic surgery, and / or robot-assisted surgery. The robotic system includes: a multi-axis robotic F / T sensor attached to a robotic arm; a multi-axis trocar F / T sensor integrated within a surgical cannula; and a robotic surgical instrument attached to the robotic arm and positioned within a surgical patient's body cavity via the trocar. The robotic system also includes processing circuitry configured to receive outputs from the robotic F / T sensor and the trocar F / T sensor. The processing circuitry is further configured to: translate and / or rotate the reference frame of one of the robotic F / T sensor and the trocar F / T sensor to the reference frame of the other F / T sensor; subtract the force and / or torque from the one F / T sensor from the force and / or torque from the other F / T sensor; and output the resulting force and / or torque applied to the surgical instrument.

[0017] Another embodiment relates to a method for performing minimally invasive surgery using a robotic surgical instrument attached to a robotic arm and positioned within a patient's body cavity via a cannula. Forces and / or torques at the robotic arm are sensed in a first reference frame. Forces and / or torques at the cannula are sensed in a second reference frame. One of the first and second reference frames is translated and / or rotated to the other reference frame. The forces and / or torques sensed in one of the first and second reference frames are subtracted from the forces and / or torques sensed in the other reference frame. The resulting forces and / or torques are output. Attached Figure Description

[0018] The present disclosure will be described more fully below with reference to the accompanying drawings, in which various aspects of the disclosure are illustrated. However, the disclosure should not be construed as limited to the aspects set forth herein. Rather, these aspects are provided to make the disclosure thorough and complete, and to fully convey the scope of the disclosure to those skilled in the art. The same reference numerals throughout refer to the same elements.

[0019] Figure 1 This is a plan view of existing robot force / torque sensors.

[0020] Figure 2 yes Figure 1 A magnified and exaggerated view of the deformable beam of the F / T sensor under applied force.

[0021] Figure 3 This is a 3D view of the cannula used in robotic surgery.

[0022] Figure 4 yes Figure 3 Top view of the casing.

[0023] Figure 5 yes Figure 3 and Figure 4 The equidistant cross-sectional view of the casing.

[0024] Figure 6 This is a side sectional view of the second casing.

[0025] Figure 7 yes Figure 6 An isometric sectional view of the casing.

[0026] Figure 8 yes Figure 6 and Figure 7 Side view of the sleeve.

[0027] Figure 9 yes Figures 3-5 A top view of the bushing, including the transducer and controller.

[0028] Figure 10 The matrix calculations for rotation and translation of forces and torques between reference frames are shown.

[0029] Figure 11 This is a three-dimensional view showing the three coordinate systems on the robotic surgical instrument assembly.

[0030] Figure 12A It is an misaligned cross-sectional view showing surgical instruments without a load in the cannula.

[0031] Figure 12BIt is an misaligned cross-sectional view showing a surgical instrument under load (bending) in the cannula.

[0032] Figure 13 This is a flowchart of a method for performing minimally invasive surgery using robotic surgical instruments attached to a robotic arm and placed in the patient's body cavity via a cannula. Detailed Implementation

[0033] For simplicity and illustrative purposes, this disclosure is described primarily with reference to exemplary aspects of the disclosure. Numerous specific details are set forth in the following description to provide a thorough understanding of the disclosure. However, it will be readily apparent to those skilled in the art that the disclosure may be practiced without being limited to these specific details. Well-known methods and structures are not described in detail in this specification so as not to unnecessarily obscure the disclosure.

[0034] Referring to the aforementioned U.S. Patent No. 10,422,707, a method for designing an F / T sensor is briefly reviewed. Figure 1 It is a '707 patent' Figure 1 A copy of the diagram shows a plan view of the force / torque sensor 10. A rigid hub 12 is connected to a rigid annular ring 14 via three deformable beams 16a, 16b, and 16c. In the illustrated embodiment, each beam 16 is directly connected to the hub 12 and to the annular ring 14 via a flexible element 17, which facilitates the deformation of the beam 16 under mechanical loads.

[0035] Strain gauges 1-6 are fixed to the upper surface of each deformable beam 16. Figure 1 It also shows the two axes of a three-dimensional reference Cartesian coordinate system (the z-direction extends beyond the figure), with analytical forces and torques referenced to these two axes. Figure 2 It is the same '707 patent. Figure 2 The copy is an enlarged view of beam 16a, showing exaggerated deformation relative to annular ring 14 due to the force F applied to hub 12. This force deforms beam 16a slightly to the left (the figure is not drawn to scale). Compressive forces are induced on the left surface of deformable beam 16a, and tensile forces on the right surface. Transducers, such as strain gauges, can be mounted on these surfaces, where they produce strong signals of opposite polarity from which the deformation can be determined, thereby determining the applied force F. In the embodiment of the '707 patent, strain gauges 1-6 are mounted only on the upper surface of deformable beam 16, spaced apart from the neutral axis 18. The '707 patent, as well as the other aforementioned patents, describes signal processing by which the multiaxial forces and / or torques between hub 12 and annular ring 14 are resolved and quantified.

[0036] Figure 3A perspective view of the cannula 110 of a cannula for minimally invasive surgery is shown. The cannula 110 includes an elongated tube 112, which is inserted into the patient's body cavity through a small incision during minimally invasive surgery. Surgical instruments are inserted into the body cavity through the tube 112 of the cannula 110. An internal seal 114 is located within the patient's body, just beneath the skin. The internal seal 114 prevents gas or fluid from escaping through the incision during surgery. A cannula F / T sensor 116 is disposed at the end of the cannula 110, opposite the internal seal 114.

[0037] Figure 4 and Figure 5 Details of a multi-axis F / T sensor 116 are shown. An annular sleeve 118 extends at least partially around a tube 112 along its length. The tube 112 and the annular sleeve 118 are relatively rigid and are connected at multiple radial locations by deformable members 120, analogous to spokes on a wheel in some embodiments. The deformable members 120 deform slightly in response to forces and / or torques between the tube 112 and the annular sleeve 118. Transducers (not shown) fixed to one or more surfaces of the plurality of deformable members 120 sense tensile and / or compressive forces caused by applied forces and / or torques on the surfaces of the deformable members 120 and generate outputs, such as electrical signals. These outputs are transmitted, for example via lines (not shown), to a controller (not shown), which resolves the sensed tensile and compressive forces as forces and / or torques along multiple axes. In one embodiment, the extended annular member 122 provides space for an internal seal or other component to be fitted onto the sleeve 110.

[0038] like Figure 5 As shown, in one embodiment, the deformable members 120 are formed in two groups of three, and the two groups are laterally spaced apart from each other along the length of the tube 112. In various embodiments, any number of deformable members 120 in each group may be radially spaced around the tube 112, and there may be more than two groups of deformable members 120 spaced apart along the tube 112.

[0039] Regardless of the specific configuration of the deformable member 120, the multi-axis F / T sensor 116 is configured to sense and analyze the force and / or torque between the tube 112 and the annular sleeve 118. During surgery, the annular sleeve 118 is held in place on the patient's body, and surgical instruments are inserted through the tube 112. The multi-axis F / T sensor 116 senses, analyzes, and reports the force and / or torque between the tube 112 and the annular sleeve 118, for example, caused by a surgeon and / or robot manipulating surgical instruments positioned within the tube 112 (and / or feeding it back to a tactile feedback system).

[0040] Typically, enough transducers are attached to the deformable member 120 to resolve forces and torques on three to six axes. Each resolved axis requires at least one deformable member 120; however, each deformable member 120 may have multiple transducers fixed thereto.

[0041] exist Figure 4 and Figure 5 In the illustrated embodiment, there are two groups of three deformable members 120 connecting the tube 112 and the annular sleeve 118. At least two deformable members 120 are required. In the illustrated embodiment, a total of six deformable members 120 are used for strength purposes; however, typical embodiments may include only three or four. The deformable members 120 can be more complex than the simple beam shown. For example, they can be L-shaped or T-shaped, and / or may include, for example, Figure 1 and Figure 2 The flexible member shown and described in '707 patent. The deformable member 120 may also be parallel or tangential to the tube 112, rather than radially as shown.

[0042] exist Figure 5 In the illustrated embodiment, the annular sleeve 118 extends only along the length of the tube 112 to enclose all (e.g., both sets) of deformable members 120 for a distance. In another embodiment (not shown), the annular sleeve 118 extends along the entire length of the tube 112. This isolates the tube 112 from forces generated by external factors unrelated to the forces applied to the tube 112. However, since the outer diameter of the sleeve 110 is now larger, a larger cut is required.

[0043] As described in the aforementioned patent, the transducer fixed to the deformable member 120 may include a strain gauge, such as a silicon strain gauge. However, the invention is not limited to strain gauges. In other embodiments, the transducer may include a capacitive sensor, a fiber Bragg grating sensor, a surface acoustic wave (SAW) sensor, or a piezoelectric sensor, or a combination thereof.

[0044] The sleeve 110 can be formed as a single system, or it can include two or more modular components assembled into an operable sleeve 110.

[0045] Figure 6 , Figure 7 and Figure 8 A slightly different sleeve 110 is shown, in which a sleeve needle F / T sensor 116 is also integrated. An annular sleeve 118 extends at least partially around the tube 112 along its length. The tube 112 and the annular sleeve 118 are relatively rigid and are connected at multiple radial locations by a deformable member 120, analogous to spokes on a wheel in some embodiments. The deformable member 120 deforms slightly in response to forces and / or torques between the tube 112 and the annular sleeve 118.

[0046] Figure 9 Show Figure 3 The sleeve 110 shows a transducer 123, in this embodiment a strain gauge, connected to the sidewall of the deformable member 120. In other embodiments, other transducers 123 may be used, and / or they may be attached to the deformable member 120 at different locations. In one embodiment, one or more transducers 123 may be attached to the tube 112 or the annular sleeve 118 close to the deformable member 120.

[0047] Transducer 123 is operably connected to controller 124. Figure 9 (Only one connection is shown in the diagram). Controller 124 includes processing circuitry 126 operatively connected to memory 128 and optionally includes input / output (I / O) circuitry 130 (as shown by dashed lines). Controller 124 may be integrated into cannula 110 or cannula needle, or may be part of a laparoscopic or robotic surgical system.

[0048] Processing circuitry 126 is configured to receive an electrical signal from transducer 123 and resolve the signal into forces and / or torques applied between the annular sleeve 118 and tube 112 along at least three axes. Algorithms for resolving the transducer output into forces and torques are known in the art and are disclosed, for example, in the aforementioned introduced patent. These algorithms are embodied as machine-readable code stored in memory 128 and accessed by processing circuitry 126.

[0049] Optional I / O circuitry can preprocess the output signal of transducer 123 before processing circuitry 126 processes it, for example by amplification, low-pass filtering to reduce noise, and performing analog-to-digital conversion. The I / O circuitry can also post-process the resolved force and torque, for example by comparing them to predetermined thresholds to issue an alarm when excessive force or torque is detected, by converting the F / T to the format required by the haptic feedback circuitry in the surgical controller, or for other purposes. Alternatively, processing circuitry 126 can perform all formatting on the output data.

[0050] Processing circuitry 126 may include any sequential state machine operable to execute machine instructions stored in memory 128 as a machine-readable computer program, such as one or more hardware-implemented state machines (e.g., discrete logic, FPGA, ASIC, etc.), programmable logic, and appropriate firmware; one or more stored programs, general-purpose processors such as microprocessors or digital signal processors (DSPs), and appropriate software; or any combination thereof.

[0051] The memory 128 may include any non-transient machine-readable medium known or that can be developed in the art, including but not limited to magnetic media (e.g., floppy disks, hard disks, etc.), optical media (e.g., CD-ROMs, DVD-ROMs, etc.), solid-state media (e.g., SRAM, DRAM, DDRAM, ROM, PROM, EPROM, flash memory, solid-state drives, etc.).

[0052] Optional I / O circuitry 126 may include receiver circuitry configured to receive, amplify, and digitize electrical signals from transducer 123. The I / O circuitry may also include transmitter or interface circuitry configured to output useful force / torque data to other systems or components, such as excessive force indicators (e.g., flashlights, audible alarms, etc.), or data for haptic feedback systems.

[0053] The cannula F / T sensor 116 is configured to sense and analyze the force and / or torque between the tube 112 and the annular sleeve 118. During surgery, the annular sleeve 118 is held in proper position on the patient's body, and surgical instruments are inserted through the tube 112. The cannula F / T sensor 116 senses, analyzes, and reports (or feeds back to a tactile feedback system) the force and / or torque between the tube 112 and the annular sleeve 118, for example, caused by a surgeon and / or robot manipulating surgical instruments positioned within the tube 112.

[0054] Although the cannula F / T sensor 116 is an improvement on the conventional robot F / T sensor 142 attached to the robot arm (see...) Figure 11 However, it still doesn't directly measure the force or torque at the tip of the surgical instrument. A single F / T sensor, whether mounted on a robotic arm or integrated into the cannula, measures the sum of the forces and torques acting on the surgical instrument and between the cannula and the patient's skin. While best surgical practices strive to minimize the latter, they are always present to some extent and distort the sensed forces and torques of the surgical instrument.

[0055] According to embodiments of this disclosure, the force and / or torque applied to the tip of the robotic surgical instrument is inferred by sensing both the robotic arm force and / or torque and the cannula force and / or torque, and then subtracting the two. This process is described herein with reference to the case where the cannula force and / or torque are subtracted from the robotic arm force and / or torque; however, this operation may be reversed, and only the surgical instrument force and / or torque will still be obtained.

[0056] Figure 11A conventional F / T sensor (referred to herein as robot F / T sensor 142) is shown mounted on a robotic arm, and a robotic surgical instrument is attached to the robotic arm. If the surgical instrument is operating on the patient's skin, robot F / T sensor 142 would be sufficient to determine the forces and / or torques experienced by the surgical instrument, for example, feeding this feedback to a tactile feedback system. However, when the surgical instrument is inserted into the patient's body cavity through a cannula 110 located in an incision in the patient's skin, at least some forces and / or torques are generated between the cannula 110 and the skin. These forces and / or torques are sensed by cannula F / T sensor 116 and subtracted from the forces and / or torques sensed by robot F / T sensor 142 to obtain the forces and / or torques experienced by the surgical instrument.

[0057] The subtracted force and / or torque are fully resolved. Some F / T sensors only output sensor outputs, which are generated in the F / T sensor's reference frame. These signals must be processed to resolve them into force and / or torque. Many techniques are known in the art to achieve this, some of which are described in detail in the aforementioned introduced patent. Some F / T sensors include processing circuitry that performs these calculations, and the sensor output is the resolved force and / or torque. Some F / T sensors may also include accelerometers, inertial measurement units (IMUs), or other circuitry that outputs useful information. For the purposes of this discussion, it is assumed that both the robot F / T sensor 142 and the cannula F / T sensor 116 output fully resolved force and / or torque, each referencing its respective sensor's local reference frame or coordinate system. For F / T sensors that only output transducer signals, external signal processing will be required, which is within the scope of the art of those skilled in the art and will not be elaborated upon here.

[0058] In order to subtract the output of the cannula F / T sensor 116 from the output of the robot F / T sensor 142, the latter's reference frame must first be aligned with the former's reference frame. At a minimum, this requires translating the reference frame of the cannula F / T sensor 116 to the position of the robot F / T sensor 142's reference frame, and may typically require rotating one or more axes.

[0059] Figure 11 The robotic surgical instrument assembly 140 and three reference frames or coordinate systems are shown: one at the robot F / T sensor 142, one at the cannula F / T sensor 116, and one at the tip of the surgical instrument 144. In this example, only translation is required; however, in general, joints or pivot points can allow the surgical instrument to be oriented in ways other than along the longitudinal axis of the robotic arm. In this case, rotation along one or more axes is also required.

[0060] For example, the reference frame for the two sensors 116, 142 can be found using accelerometers, IMUs, magnetometers, GPS data, capacitance measurements using the tool, linear encoders between the tool and the cannula, or various other methods. Furthermore, on the robot side, the reference frame can be found from encoders on the robot arm joints, which can be resolved to the final position. This can then be used to determine the reference frame for the cannula 110 using methods such as vision or laser measurements. It can also be approximated mathematically by examining the resolved forces and torques of the two sensors 116, 142 to understand how far apart they are.

[0061] Once the angle between the two reference frames and the distances on all axes are found, the task is complete. Figure 10 The calculation 200 shown is used to place the forces and torques from the two sensors in the same reference frame. Figure 10 This diagram illustrates a procedure for calculating the force and torque transformation matrix 220 to transform the output of the cannula needle F / T sensor 116 to the reference frame of the robot F / T sensor 142 (and vice versa). Block 202 indicates the rotation angles Rx, Ry, and Rz of the three axes. These are detailed in Rz matrix 204, Ry matrix 206, and Rx matrix 208. Multiplying these three matrices yields a 3×3 rotation matrix 210. The 3×3 rotation matrix 210 is then expanded into a 6×6 rotation matrix 214 by copying and padding, the contents of which are shown in block 212. Block 216 indicates the translation distances Dx, Dy, and Dz, which are input into the 6×6 translation matrix 220, the contents of which are shown in block 218. Multiplying the 6×6 rotation matrix 214 and the 6×6 translation matrix 220 yields a 6×6 force and torque transformation matrix 222.

[0062] The force and / or torque output of the cannula F / T sensor 116 is multiplied by the force and torque transformation matrix 222 and translated to the reference frame of the robot F / T sensor 142. The translated cannula F / T sensor 116 output is then subtracted from the corresponding robot F / T sensor 142 output. For F / T sensors 116 and 142 that output data for fewer than six axes, the missing axes are simply omitted in the rotation / translation calculations. The result is the projected force and / or torque acting on the robotic surgical instrument attached to the robotic arm and positioned in the patient's body cavity via the cannula 110. These force and / or torque values ​​can be used in the tactile feedback mechanism of the robotic surgical system, used by automated programs, stored, and used for training surgeons and / or machine learning models, etc.

[0063] In some applications, knowing the location of specific points on a surgical instrument (such as the tip) is important, or at least useful. When the location of the instrument tip is known or can be calculated with high precision, the force and torque transformation matrix 222, as described above, is used to rotate and / or translate the forces and / or torques sensed by the robot F / T sensor 142 (compensated for the forces and / or torques sensed by the cannula F / T sensor 116) to the desired location, such as the surgical instrument tip. The location of the tip can be determined, for example, by vision, magnetometer, GPS, inductive sensors built into the cannula, IMU data, accelerometer, etc.

[0064] Surgical instruments are designed to be very thin for several reasons. Thin instruments allow for greater precision and control. The slender design also minimizes tissue damage and reduces the risk of infection by limiting the size of incisions. Furthermore, thin instruments can more easily traverse narrow and complex anatomical structures, enhancing the surgeon's ability to perform minimally invasive procedures.

[0065] Due to their thin design and the resulting material scarcity in surgical instruments, they often exhibit significant deflection. This deflection causes a change in the coordinate system at the tool tip, which in turn alters the values ​​required for tool transformation. For low-precision applications, this change can be ignored, but for other applications, it must be measured or estimated.

[0066] In one embodiment, the location of a desired point (e.g., a tip) on the surgical instrument is determined mathematically. Given the stiffness of the surgical instrument, the tip position is calculated by understanding the approximate direction of the load applied to the tip. The angular difference between the Z-axis of the robot F / T sensor 142 and the cannula F / T sensor 116 in the reference frame must also be known. Figure 11 The relevant frame of reference is shown.

[0067] If there is an angular difference between the two Z-axis, and the cannula is mathematically confirmed to be in contact with the surgical instrument, then there are two possible states. Figure 12A This illustrates a state in which the instrument is not loaded or bent, but simply "tilted" inside the cannula. Figure 12B This indicates that the instrument is under load and deflected. Figure 12B The view shows the load applied to the instrument, with its force vector pointing in the direction from which the tool originates. This is not always the case, and the output vector at the far end of the tool will change accordingly. Figure 12A and Figure 12B The view is simplified and used only to describe possibilities.

[0068] By understanding the direction and magnitude of the force applied to the tip of a surgical instrument, the position of the tip can be determined mathematically using various methods.

[0069] In one embodiment, when the tip is unloaded, the dimensional difference between the inner width of the cannula and the width of the surgical instrument, combined with angular mismatch and a known Z distance, is used to determine the approximate position of the instrument tip relative to the two F / T sensors 116, 142.

[0070] If the tip is under load, a simple vector is calculated based on the theoretical direction of departure from the cannula. Depending on the tool stiffness, additional transformations may be performed to account for tool deflection after departure from the cannula. Alternatively, a simplified finite element analysis can be performed to quantify the amount of deflection.

[0071] Figure 13 This diagram illustrates the steps of a method 300 for performing minimally invasive surgery using a robotic surgical instrument attached to a robotic arm and positioned within a patient's body cavity via a cannula. Force and / or torque are sensed at the robotic arm in a first reference frame (block 302). Force and / or torque are sensed at the cannula in a second reference frame (block 304). One of the first and second reference frames is translated and / or rotated to the other reference frame (block 306). The force and / or torque sensed in one of the first and second reference frames is subtracted from the force and / or torque sensed in the other reference frame (block 308). The resulting force and / or torque is output (block 310).

[0072] Compared to existing technologies, the embodiments of this disclosure offer significant advantages and can achieve one or more of the following technical effects. Due to the challenging environment of surgical preparation and use, surgical instruments must be highly robust and reliable. Furthermore, instruments are as thin as possible to minimize the size of the incision in the patient's body. Because of these limitations, directly positioning the F / T sensor at the desired force / torque sensing point (typically the tip of the surgical instrument) is extremely difficult. A single F / T sensor mounted elsewhere along the robotic stack will not produce accurate force / torque readings because it incorporates both the surgical instrument and the cannula / body force and torque. By using two multi-axis F / T sensors 116, 142, and subtracting the force of the cannula 110 from the output of the robotic F / T sensor 142 (and vice versa), the force and / or torque applied to the surgical instrument itself can be estimated more accurately. Both the robotic F / T sensor 142 and the cannula F / T sensor 116 are external to the body, where there is more space to construct deformable structures. Furthermore, the same robotic arm and cannula 110 can be used with a variety of surgical instruments, so the cost of F / T sensors 116, 142 is amortized and does not need to be produced separately for each surgical instrument.

[0073] Generally, all terms used herein should be interpreted according to their ordinary meaning in the relevant technical field, unless explicitly given and / or implied to have a meaning different from that in the context of their use. Unless otherwise expressly stated, all references to elements, devices, components, apparatuses, steps, etc., should be interpreted openly as referring to at least one instance of that element, device, component, apparatus, step, etc. Where appropriate, any feature of any aspect disclosed herein may be applied to any other aspect. Similarly, any advantage of any aspect may be applied to any other aspect, and vice versa. Other objects, features, and advantages of the included aspects will be apparent from the specification.

[0074] As used herein, the term “configured to” means to operate in a particular way, organized, adapted, or arranged; this term is synonymous with “designed to”, or, in the case of circuitry and / or software, with “programmed to”. As used herein, “surgical tool” refers to any device that can be inserted into a patient’s body cavity during minimally invasive surgery, whether it performs a specific surgical function or supports other surgical tools. For example, a laparoscopic camera is a surgical “tool” even if it does not directly interact with the patient’s body. As used herein, the coordinating conjunction “or” has the meaning of the Boolean logic operator OR, for example, “A or B” is true if A is true, B is true, or both A and B are true; it is false only if both A and B are false. Therefore, the word “or” encompasses the common phrase “and / or”.

[0075] Of course, this disclosure may be practiced in ways other than those specifically set forth herein without departing from its essential characteristics. All aspects given should be considered illustrative rather than restrictive, and all variations in the meaning and scope of the appended claims are intended to be included.

Claims

1. A dual-multi-axis force or torque (F / T) sensor robotic system for minimally invasive surgery, robotic surgery, or robot-assisted surgery, comprising: Multi-axis robot F / T sensor attached to robot arm; Multi-axis cannula F / T sensor integrated into the surgical cannula; and A robotic surgical instrument, which is attached to the robotic arm and inserted into the body cavity of the surgical patient via the cannula; and The processing circuit is configured to receive the outputs of the robot F / T sensor and the cannula F / T sensor, and is also configured to... The reference frame of one of the robot F / T sensor and the cannula F / T sensor is translated or rotated to the reference frame of the other F / T sensor. Subtract the force or torque of one sensor from the force or torque of the other F / T sensor; and The output is the force or torque applied to the surgical instrument.

2. The robot system of claim 1, wherein one or both of the F / T sensors output a resolved force or torque relative to its reference frame to the processing circuit.

3. The robot system of claim 1, wherein one of the F / T sensors outputs a signal from a transducer in the F / T sensor to the processing circuit, and wherein the processing circuit is further configured to resolve the signal from the transducer into a force or torque in the reference frame of the F / T sensor.

4. The robot system of claim 1, wherein the processing circuit is further configured to: Calculate the position of a predetermined portion of the robotic surgical instrument; and The reference frame of the F / T sensor is translated or rotated to the position of a predetermined part of the robotic surgical instrument.

5. The robotic system of claim 1, wherein the surgical cannula comprises a cannula, the cannula including a tube configured for insertion into a patient's body cavity, and wherein a multi-axis cannula F / T sensor integrated within the surgical cannula comprises: An annular sleeve, which is in a spaced-apart annular relationship with the tube; and At least two instrumented deformable components connecting the tube and the annular sleeve; The multi-axis cannula needle F / T sensor is configured to sense and resolve forces or torques applied between the annular sleeve and the tube along at least three axes.

6. A method for performing minimally invasive surgery using robotic surgical instruments attached to a robotic arm and inserted into a patient's body cavity via a cannula, the method comprising: Sensing force or torque at a first position in a first reference frame; Sensing force or torque at a second position in a second reference frame; The force or torque sensed in the second reference frame is translated or rotated to the first reference frame; Subtract the force or torque sensed in the second reference frame after translation or rotation from the force or torque sensed in the first reference frame; and The force or torque obtained from the output.

7. The method of claim 6, wherein sensing force or torque includes receiving a signal from a transducer in a force / torque (F / T) sensor, and further includes resolving the transducer signal to force or torque in a reference frame of the F / T sensor.

8. The method of claim 6, wherein translating or rotating the force or torque sensed in the second reference frame to the first reference frame comprises: Determine a 3×3 rotation angle matrix for each of the three orthogonal directions required to rotate and align the second reference frame with the first reference frame; Multiply the three 3×3 rotation angle matrices together to obtain a 3×3 rotation matrix; The 3×3 rotation matrix is ​​expanded into a 6×6 rotation matrix by copying and padding; Determine the distance in each of the three orthogonal directions required to translate the second reference frame to align it with the first reference frame, and input these distances into a 6×6 translation matrix; Multiplying the 6×6 rotation matrix by the 6×6 translation matrix yields a 6×6 force and torque transformation matrix; and The force or torque measurement value sensed in the second reference frame is multiplied by the 6×6 force and torque transformation matrix.

9. The method of claim 6, wherein the first reference frame is centered on the multi-axis robot F / T sensor attached to the robot arm, and the second reference frame is centered on the multi-axis trocar F / T sensor integrated within the trocar.

10. The method of claim 6, wherein the second reference frame is centered on the multi-axis robot F / T sensor attached to the robot arm, and the first reference frame is centered on the multi-axis trocar F / T sensor integrated within the trocar.

11. The method of claim 6, further comprising: Determine the position of a predetermined portion of the robotic surgical instrument; and The reference frame is translated or rotated from one of the first and second reference frames to the position of a predetermined portion of the robotic surgical instrument.

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