Force measurement device, surgical instrument device, and surgical system

Abstract

Provided is a force measurement device for measuring force acting on the tip end of a small-diameter instrument, the force measurement device being capable of measuring multi-axis force.　This force measurement device comprises: a mechanical unit having a first state in which the radius thereof from a central axis parallel to the direction of a first axis is less than a predetermined value and a second state in which the radius thereof from the central axis is greater than the predetermined value; and a strain sensor attached to a strain generating element included in the mechanical unit. The force measurement device is capable of measuring multi-axis force including the first axis and a second axis orthogonal to the first axis. The mechanical unit is elongated in the direction of the first axis in the first state, and in the second state is deformed in a direction of increase in the second axis orthogonal to the first axis.

Description

Force measurement device, surgical tool device, and surgical system

[0001] The technology disclosed in this specification (hereinafter referred to as "the present disclosure") relates to a force measuring device that measures force, a surgical tool device, and a surgical system.

[0002] Generally, surgical procedures are difficult tasks that rely on the surgeon's sensory motor skills. In particular, in surgeries such as retinal surgery, which use minute surgical instruments in a small, fragile environment, the surgeon must perform movements on the order of microns. In such procedures, it is desirable to enable the surgeon to sense the force in order to prevent imperceptible minute forces from invading the affected area. For example, a method has been proposed in which a force sensor is placed near the tip of a surgical instrument used in retinal microsurgery to directly measure the contact force acting between the biological tissue inside the eye and the tip of the instrument (see Patent Document 1).

[0003] JP-T-2013-536013 A JP-A-2009-288198 A JP-A-2022-156314 A

[0004] An object of the present disclosure is to provide a force measuring device, a surgical tool device, and a surgical system that measure the force acting on the tip of a small-diameter instrument such as a surgical tool.

[0005] A first aspect of the present disclosure is a force measuring device capable of measuring multi-axial forces including the first axis and a second axis perpendicular to the first axis, the force measuring device comprising: a mechanical section having a first state in which a diameter from a central axis parallel to a direction of a first axis is smaller than a predetermined value, and a second state in which a diameter from the central axis is larger than the predetermined value; and a strain sensor attached to a strain-generating element included in the mechanical section.

[0006] In the first state, the mechanical unit is elongated in the direction of the first axis, and in the second state, it deforms in a direction increasing in the direction of the second axis. Specifically, the mechanical unit is configured by arranging a plurality of folding structures, each made of a pair of flat plates with a hinge at the center, with the hinge facing the direction of the second axis, and connecting the upper and lower ends of each folding structure to an upper block and a lower block, respectively. In the first state, the upper block and the lower block are separated, and each folding structure stretches straight, thereby reducing its diameter. In the second state, the upper block and the lower block are brought closer together, and each folding structure bends, causing each hinge to move in the direction of the second axis, thereby increasing its diameter. A flat plate of each folding structure includes the strain element, and the strain sensor is attached by adhesive to the flat portion of the strain element.

[0007] A second aspect of the present disclosure is a surgical tool device including: a treatment tool; a mechanical unit that supports the treatment tool and has a first state in which a diameter from a central axis parallel to a direction of a first axis is smaller than a predetermined value and a second state in which a diameter from the central axis is larger than the predetermined value; and a strain sensor attached to a strain generating body included in the mechanical unit.

[0008] A third aspect of the present disclosure is a surgical system comprising a leader device and a follower device, wherein the follower device comprises a robot that operates a surgical tool device, the surgical tool device comprises a treatment tool, a mechanical unit that supports the treatment tool, and a strain sensor attached to a strain-generating body included in the mechanical unit, the mechanical unit has a first state in which a diameter from a central axis parallel to the direction of a first axis is smaller than a predetermined value, and a second state in which the diameter from the central axis is larger than the predetermined value, and the leader device comprises an operation user interface unit that inputs instructions for an operation amount to the robot, and a presentation unit that presents a force sensation based on an external force measured by the strain sensor.

[0009] However, the term "system" used here refers to a logical collection of multiple devices (or functional modules that realize specific functions), regardless of whether each device or functional module is contained within a single housing. In other words, both a single device consisting of multiple parts or functional modules and a collection of multiple devices are considered "systems."

[0010] FIG. 1 is a diagram showing a specific example in which the present disclosure is applied to a surgical tool device for retinal surgery. FIG. 2 is a diagram showing a specific example in which the present disclosure is applied to a surgical tool device for retinal surgery. FIG. 3 is a diagram showing a specific example in which the present disclosure is applied to a surgical tool device for retinal surgery. FIG. 4 is an enlarged view of the force sensor unit 102 in an unfolded state. FIG. 5 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 6 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 7 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 8 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 9 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 10 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 11 is a diagram showing the manufacturing process of the force sensor unit 102. FIG. 12 is a flowchart showing a general outline of the procedure from inserting the surgical tool device 100 into the eyeball to starting retinal surgery. FIG. 13 is a flowchart showing a general outline of the procedure for manufacturing the force sensor unit 102. Fig. 14 is a diagram showing the force sensor unit 102 transitioning from a stored state to an unfolded state. Fig. 15 is a diagram showing the force sensor unit 102 transitioning from a stored state to an unfolded state. Fig. 16 is a diagram showing the force sensor unit 102 transitioning from a stored state to an unfolded state. Fig. 17 is a diagram showing an example of a schematic functional configuration of a surgical system 1700. Fig. 18 is a diagram showing a state in which an external force is applied to the tip of an elongated object in a direction perpendicular to the longitudinal direction. Fig. 19 is a diagram showing a state in which an external force is applied to the tip of an elongated object in a direction perpendicular to the longitudinal direction.

[0011] Hereinafter, embodiments of the present disclosure will be described in the following order with reference to the drawings. Note that the embodiments described below and their dimensions, materials, and other specific numerical values ​​are merely examples to facilitate understanding of the present disclosure and are not intended to limit the technical scope of the present disclosure. Furthermore, the configuration of each of the following embodiments can be combined with the configuration of other embodiments.

[0012] A. Overview B. Specific configuration example C. Simple manufacturing method for a small multi-axis force sensor D. Other application examples E. Surgical system F. Summary

[0013] A. Overview For example, in surgeries using fine surgical instruments in small, fragile environments, such as retinal surgery, a small, highly sensitive multi-axis force sensor must be constructed to prevent imperceptible minute forces from invading the affected area. Furthermore, a simple structure is desirable to enable placement of such a small force sensor at the tip of the surgical instrument. A simple structure not only facilitates compliance with medical requirements such as cleaning and re-sterilization, but also reduces the impact on manufacturing costs for surgical instruments that are disposable after initial sterilization.

[0014] Multi-axis force sensors characterized by their small diameter (see, for example, Patent Document 1) have the problem that it is difficult to achieve high sensitivity in the longitudinal direction. However, the "longitudinal direction" referred to in this specification means the long direction of a cylindrical or rectangular slender object such as a surgical tool.

[0015] Fig. 18 shows a state in which an external force F is applied to the tip of an elongated object 1801 in a direction perpendicular to the longitudinal direction. Fig. 19 shows a state in which an external force F is applied to the tip of the same elongated object 1801 in a direction parallel to the longitudinal direction. In each figure, the direction perpendicular to the longitudinal direction of the elongated object 1801 is defined as the x-direction, and the longitudinal direction is defined as the z-direction.

[0016] The elongated object 1801 is a cantilever with a fixed end at its base and a free end at its tip. Suppose that a strain sensor 1802 attached near the base of the elongated object 1801 measures strain when an external force is applied. When an external force F is applied to the tip of the elongated object 1801 in a direction perpendicular to the longitudinal direction, the strain sensor 1802 measures a strain ε1 that is proportional to the distance l from the fixed end to the point of application of the external force F and inversely proportional to the cube of the diameter D of the elongated object 1801, according to the principle of a cantilever, as shown in the following equation (1). On the other hand, when the external force F is applied to the tip of the elongated object 1801 in a direction parallel to the longitudinal direction, the strain sensor 1802 measures a strain ε2 that is inversely proportional to the square of the diameter D of the elongated object 1801, as shown in the following equation (2). In each equation, E is Young's modulus.

[0017]

[0018]

[0019] Here, in the following equation (3) for calculating the ratio of strain ε1 to ε2, if, for example, the distance l from the fixed end to the point of application of external force F is 10 mm and the diameter D of elongated object 1801 is 1 mm, when external force F is applied in a direction perpendicular to the longitudinal direction, a strain ε1 is generated that is k = 80 times larger than the strain ε2 when external force F is applied in a direction parallel to the longitudinal direction.

[0020]

[0021] The reason why the strain varies greatly depending on the direction of the external force applied to the elongated object 1801 is that the rigidity of the elongated object 1801 varies greatly depending on the direction, and this is also referred to as "rigidity anisotropy" in this specification. In developing a multi-axis force sensor, in order to achieve both strength in the direction perpendicular to the longitudinal direction and sensitivity in the direction parallel to the longitudinal direction, it is necessary to devise a way to reduce the rigidity anisotropy. This point will be explained below using mathematical formulas.

[0022] Eliminating l from the above equations (1) and (3) leads to the following equation (4).

[0023]

[0024] The conditional expression for sensitivity in the direction parallel to the longitudinal direction is the minimum rated load in the above formula (2) as F min , the minimum strain at that time is ε 2,min As a result, the following equation (5) is obtained.

[0025]

[0026] On the other hand, the conditional formula for the strength in the direction perpendicular to the longitudinal direction is the maximum rated load in the above formula (4) as F max , the strain at that time is ε 1,max As a result, the following equation (6) is obtained.

[0027]

[0028] From the above expressions (5) and (6), the following conditional expression (7) is obtained for the diameter D of the elongated object 1801.

[0029]

[0030] The condition for D to have a solution is given by the following equation (8).

[0031]

[0032] Furthermore, the minimum rated external force F min and maximum rated external force F max When the ratio of j (>1) is given by the following relational expression (9):

[0033]

[0034] From the above equations (8) and (9), the minimum rated external force F min By eliminating, the following equation (10) is calculated.

[0035]

[0036] Here, when the external force tolerable to the material is applied, the critical stress Eε 1,max = σ 1,max The above equation (10) can be transformed into the following equation (11).

[0037]

[0038] The above formula (11) indicates that the larger k is, that is, the higher the stiffness anisotropy is, the smaller the longitudinal strain ε 2 that occurs when the minimum rated load is applied.

[0039] From the above considerations, it can be concluded that in order to achieve both strength in the direction perpendicular to the longitudinal direction and sensitivity in the direction parallel to the longitudinal direction, it is necessary to reduce k as much as possible, i.e., to devise a way to reduce stiffness anisotropy.

[0040] Let us consider a case where stainless steel is used for the elongated object 1801. 1,max = 500 x 10 6 , E = 200 × 10 9 , k = 80, j = 1000, the strain ε at the minimum rated load 2,min is calculated as in the following equation (12).

[0041]

[0042] The detection limit of strain measurement by a general strain sensor is several μST (10 -6 Considering that the strain is 0.03 μST, it is difficult to measure the calculated value. In contrast, when there is no stiffness anisotropy, that is, when k = 1, the strain ε 2,min is 2.4 x 10 -6 improves to.

[0043] If sensitivity in the longitudinal direction is low, there are concerns that the measurement values ​​will contain noise greater than the rated value, and that other axes will be affected by interference.One method of improving sensitivity in the direction parallel to the longitudinal direction is to reduce the rigidity in the longitudinal direction by laser-machining a tubular strain-generating element to create grooves, but this has the problem of reducing strength in the direction perpendicular to the longitudinal direction.

[0044] The present disclosure proposes a force measurement device that can measure with high sensitivity both external forces applied in a direction perpendicular to the longitudinal direction of an elongated object and external forces applied in a direction parallel to the longitudinal direction, while achieving both strength in a direction perpendicular to the longitudinal direction and sensitivity in a direction parallel to the longitudinal direction. The force measurement device according to the present disclosure is characterized in that it uses a flexure element that, when not in use, is in a stored state in which the diameter from a central axis parallel to the longitudinal direction is smaller than a predetermined value (i.e., small diameter), but when in use, is deformed to a deployed state in which the diameter from the central axis is larger than a predetermined value (i.e., the diameter increases), thereby improving the aspect ratio (i.e., rigidity anisotropy is eliminated).

[0045] B. Specific Configuration Example In this section B, a specific example in which the present disclosure is applied to a surgical tool device for retinal surgery (or fundus surgery) will be described.

[0046] 1 to 3 show step-by-step examples of the operation of a surgical tool device 100 according to the present disclosure, which is applied to retinal surgery. Fig. 1 shows the state before the thin-diameter surgical tool device 100 is inserted into the eyeball 110, Fig. 2 shows the state in which the surgical tool device 100 remains thin immediately after being inserted into the eyeball 110 via a trocar 111, and Fig. 3 shows the state in which the diameter of the strain-generating body structure portion is increased and force measurement is possible after the surgical tool device 100 is inserted into the eyeball 110 via the trocar 111.

[0047] The surgical tool device 100 has a treatment tool 101 at its tip (distal end), and a support section 103 on the base side holds the treatment tool 101 via a force sensor section 102. Examples of treatment tools 101 for retinal surgery (or fundus surgery) include a vitreous cutter that removes the vitreous body, a peeling tool that peels back a membrane on the retina, and a laser photocoagulator that irradiates a laser on the retina to coagulate it, but the present disclosure is not limited to a specific treatment tool.

[0048] 1 to 3 show specific examples of applying the surgical tool device 100 to retinal surgery. Also, Fig. 12 shows, in the form of a flowchart, a schematic diagram of the procedure from inserting the surgical tool device 100 into the eyeball to starting retinal surgery.

[0049] Initially, as shown in Fig. 1, the surgical tool device 100 is in a stored state in which the diameter from the central axis is smaller than a predetermined value (i.e., a small diameter) before being inserted into the eyeball 110 (step S1201). A trocar 111 is inserted into one or more small holes with a diameter of approximately 20 millimeters drilled in the eyeball 110. Then, as shown in Figs. 1 and 2, the surgical tool device 100 is inserted into the eyeball through the trocar 111 (step S1202). Up to this point, the force sensor unit 102 is in a closed stored state with a small diameter. Because it is in a stored state with a small diameter, the force sensor unit 102 can be inserted into the eyeball through the trocar 111.

[0050] 3, the force sensor unit 102 deforms within the eyeball so that the diameter from the central axis becomes larger than a predetermined value (i.e., the diameter increases), and the force sensor unit 102 enters an expanded state in which force can be measured (step S1203). In the expanded state, the force sensor unit 102 can achieve both strength in a direction perpendicular to the longitudinal direction and sensitivity in a direction parallel to the longitudinal direction, and is in the best usable state in which it can suitably measure external forces in multiple axial directions applied to the treatment tool 101 at the distal end. Note that it is desirable to expand the force sensor unit 102 after removing the vitreous body.

[0051] 4 shows an enlarged view of the force sensor unit 102 in the deployed state. In this embodiment, a strain element of a Sarras link mechanism is applied to the force sensor unit 102 in order to deform it so that its diameter increases. A Sarras link mechanism is generally a three-dimensional spatial mechanism with a simple structure that can convert rotational motion into linear motion without a guide.

[0052] The coaxial link mechanism used in this embodiment, shown in Figure 4, is configured by arranging four folding structures consisting of a set of flat plates with a hinge at the center so that each hinge faces radially of the central axis (in this embodiment, the longitudinal direction of the force sensor unit 102 (or surgical tool device 100) is the central axis), and connecting the upper and lower ends of each folding structure to the upper end block 401 (treatment tool 101 side) and the lower end block 402 (support unit 103 side), respectively. When the upper end block 401 and the lower end block 402 move apart, each folding structure extends straight, and the coaxial link mechanism is in its smallest diameter storage state. Conversely, when the upper end block 401 and the lower end block 402 approach each other, each folding structure bends at the hinge portion, and each hinge moves radially of the central axis, so that the coaxial link mechanism is in its expanded state with an increased diameter. The relative movement between the upper end block 401 and the lower end block 402 is a linear movement restricted in the longitudinal direction.

[0053] In this embodiment, a flexural link mechanism with hinges on four sides is used, but a flexural link mechanism that forms a polyhedron, such as a flexural link mechanism with hinges on three sides or a flexural link mechanism with hinges on six sides, may also be used. Generally, flexural link mechanisms are used to convert rotational motion into linear motion. Of course, a link mechanism other than a flexural link mechanism or a mechanism other than a link mechanism may be used to realize a structure in which the force sensor unit 102 deforms so as to increase in diameter.

[0054] In the example shown in Figure 4, the force sensor unit 102, which is made of a smooth link mechanism, has a thin outer diameter of approximately 1 millimeter or less when closed and stored in a long, thin rod shape (in the example shown in Figure 4, the "predetermined value" that determines whether the force sensor unit 102 is in a stored state is 1 millimeter). Therefore, when applied to retinal surgery, as shown in Figures 1 and 2, the force sensor unit 102 is passed through a small hole or gap such as a trocar 111 while in a thin, stored state, and then deployed so that its diameter increases inside the eyeball 110 as shown in Figure 3, enabling force detection along multiple axes. Furthermore, by deploying the smooth link mechanism during use, the force sensor unit 102 can assume a three-dimensional structure with low rigidity anisotropy.

[0055] C. Simple manufacturing method for a small multi-axis force sensor Generally, the strain sensor used in a force sensor has a complex three-dimensional shape including irregularities (see, for example, Patent Document 2), making the process of attaching the strain sensor to the strain sensor complicated. In many cases, the process of attaching the strain sensor to the strain sensor in the force sensor manufacturing process is performed manually using tweezers. When the strain sensor has a complex three-dimensional shape, highly skilled techniques are required to attach the strain sensor in the correct position.

[0056] In this embodiment, the force sensor unit 102 utilizes a radial link mechanism in which four folding structures, each consisting of a set of flat plates with a hinge at the center, are arranged so that each hinge faces in the radial direction of a central axis that coincides with the longitudinal direction of the force sensor unit 102 (or surgical tool device 100), and the upper and lower ends of each folding structure are connected to an upper end block and a lower end block, respectively. A flat plate in each folding structure includes a strain element, and the strain sensor is attached by bonding to the flat portion of the strain element, simplifying the strain sensor attachment process. If the attachment location has a simple shape, such as a flat plate, rather than a complex shape, it is relatively easy for even an unskilled craftsman to attach the strain sensor in the correct position.

[0057] 5 to 11 show the manufacturing process of the force sensor unit 102. Also, Fig. 13 shows a schematic flowchart of the procedure for manufacturing the force sensor unit 102. A simple manufacturing method for a small multi-axis force sensor will be described below with reference to Figs. 5 to 11 and 13.

[0058] FIG. 5 shows the state before the flexural link mechanism is assembled, i.e., the four folding structures 501-504 are arranged on a flat surface. The flexural elements 511-514 (shown in light gray in the figure) are formed on a portion of the flat surface of each folding structure 501-504. The flexural elements 511-514 are required to be thin enough to improve sensitivity while ensuring strength. Furthermore, considering their use inside the body, such as the eyeball, they are preferably made of a material that does not expand with body temperature, i.e., has a low temperature expansion coefficient. For example, the flat flexural elements 511-514 are fabricated using stainless steel, titanium alloy, or liquid metal. Furthermore, for the portions of the folding structures 501-504 other than the flexural elements 511-514, thin rigid bodies may be attached to both sides of a flexible plastic film such as polyimide to form link sections, with hinges formed at the slits in the rigid bodies. A method of constructing a folding structure by attaching rigid bodies to a plastic film is disclosed, for example, in Patent Document 3. By using such a manufacturing method, it is possible to manufacture a small, thin force sensor portion 102 having a diameter of 1 mm or less using micromachining technology.

[0059] First, strain sensors 521 to 524 are mounted on the flat strain generating bodies 511 to 514 of the folding structures 501 to 504, respectively (step S1301).

[0060] FIG. 6 shows the strain sensors 521-524 mounted on the strain bodies 511-514 of each folded structure 501-504, respectively. In this embodiment, FBG (Fiber Bragg Grating) sensors are used for the strain sensors 521-524. An FBG sensor is a sensor constructed by engraving a diffraction grating along the longitudinal axis of an optical fiber. It can detect changes in the spacing of the diffraction grating due to strain caused by an applied force or expansion or contraction caused by temperature changes as a change in the wavelength of reflected light relative to incident light in a predetermined wavelength band (Bragg wavelength) (as is well known). The wavelength change detected by the FBG sensor can then be converted into the underlying strain, stress, or temperature change. Of course, other types of strain detection elements widely known in the industry, such as capacitance sensors, semiconductor strain gauges, and foil strain gauges, could also be used as strain sensors. However, FBG sensors are considered more preferable given their advantages, such as low transmission loss and the ability to withstand sterilization and strong magnetic field environments required for medical purposes.

[0061] 7 shows how the installed strain sensors 521-524 are attached to the strain bodies 511-514 using adhesives 531-534, respectively. The strain sensors 521-524 are fixed to the strain bodies 511-514 by adhesive bonding. Because the surgical tool device 100 is sterilized before use, it is necessary to use an adhesive (for example, a thermosetting or photocurable adhesive) that is highly heat-resistant and corrosion-resistant and compatible with the sterilization process. Examples of sterilization processes include autoclaving (high-temperature, high-pressure processing), EOG (ethylene oxide gas) sterilization, and X-ray sterilization.

[0062] It can be seen from Figures 5 to 7 that the folding structures 501 to 504 on the four sides before assembly are flat, which simplifies the process of attaching and adhering the strain sensors 521 to 524 to the strain elements 511 to 514.

[0063] Next, the strain sensors 521-524 are attached to the strain bodies 511-514, and then the folded structures 501-504 on the four sides are wound up (step S1302) as shown in Figures 8-10, completing the tubular coarse link mechanism (step S1303). Note that, as an option, the tubular coarse link mechanism may be released and cut (a process for adjusting it to an appropriate size and shape) (step S1304).

[0064] Then, by pushing (or pulling) the distal end longitudinally toward the base, each of the folding structures 501-504 bends, deforming to increase its diameter, and transitioning from the stored state to the deployed state (step S1305), as shown in Figure 11. Figure 11 shows the deployed state after the surgical tool device 100 has been inserted into the body, such as the eyeball, and the aspect ratio improves (i.e., rigidity anisotropy is eliminated). The force sensor unit 102, which is made up of a Sarras link mechanism, has a simple structure, so that gases and other substances are less likely to remain even when sterilization or disinfection processes, such as autoclaving (high-temperature, high-pressure processing), EOG (ethylene oxide gas) sterilization, or X-ray sterilization, are performed before use, making it safe for use inside the body.

[0065] Figures 14 to 16 show how the force sensor unit 102 of the SPR link mechanism transitions from a stored state to an unfolded state. Figure 14 shows the stored state in which each folding structure 501 to 504 is extended, causing the SPR link mechanism to have its smallest diameter. Figure 15 shows how, when the tip end of each folding structure 501 to 504 is pulled toward the base using a traction unit 1501 inserted inside the SPR link mechanism, the hinges expand radially as each folding structure 501 to 504 bends, causing the SPR link mechanism to deform so that its diameter increases. As can be seen from Figures 14 to 16, changing the hinge angle of each folding structure 501 to 504 produces linear movement in the longitudinal direction.

[0066] The central traction portion 1501 may be, for example, a wire or a rod. Figure 16 shows the unfolded state in which each of the folding structures 501-504 is bent to its maximum extent and the diameter of the parallel link mechanism is at its maximum. Note that when it is desired to extend each of the folding structures 501-504 again and return them to their original stored state, the restoring force of the hinges may be relied upon, or a spring may be provided to impart a restoring force to the hinges.

[0067] The deployed state of the force sensor unit 102 is the best state for use, since it can achieve both strength in a direction perpendicular to the longitudinal direction and sensitivity in a direction parallel to the longitudinal direction, and can suitably measure external forces in multiple axial directions applied to the distal end treatment tool 101. Therefore, as shown in Figure 3, after the surgical tool device 100 is inserted into the eyeball, the force sensor unit 102 transitions to the deployed state.

[0068] 5 to 11, by using a manufacturing method in which multiple folding structures made by laminating a rigid body to a plastic film are wound up to assemble a smooth link mechanism, it is possible to simply and inexpensively manufacture a small, thin force sensor unit 102 with a diameter of about 1 millimeter or less. Such a force sensor unit 102 can be applied to a fine surgical tool device 100 used in a small-scale, fragile environment such as retinal surgery.

[0069] D. Other Application Examples The present disclosure can be described as a force measurement device using a Sarras link mechanism. The Sarras link mechanism is capable of linear motion constrained in the direction of the central axis (i.e., the longitudinal direction), and the hinges of each of the multiple folding structures are arranged so as to face in the radial direction of the central axis. The Sarras link mechanism has a stowed state in which each folding structure is expanded to a small diameter, and an expanded state in which each folding structure is bent to an increased diameter. In the expanded state, the stiffness anisotropy is improved, enabling both strength in a direction perpendicular to the longitudinal direction and sensitivity in a direction parallel to the longitudinal direction to be achieved.

[0070] In the above sections B and C, we have described a force measurement device that uses a small, thin-diameter SPR mechanism manufactured using micromachining technology as a strain element. For example, when applied to surgeries other than retinal surgery, such as laparoscopic surgery, the SPR mechanism and force measurement device can be manufactured in a size appropriate for the application. On the other hand, for relatively large sizes, the SPR mechanism is not limited to the manufacturing method of constructing a SPR mechanism using a folding structure in which a rigid body is bonded to a plastic film, and the SPR mechanism may also be manufactured using a folding structure made of general mechanical parts, such as flat plates such as metal plates connected together with bearings.

[0071] Devices using the Sarasu link mechanism are not limited to force measurement devices, but can also be used for a variety of other measurements and even for non-measurement purposes.The Sarasu link mechanism has a stored state in which each folding structure is extended to a narrow diameter, and an unfolded state in which each folding structure is bent to an increased diameter, so one possible use case scenario is to move the device in the stored state through a narrow hole or gap, and then transition to the unfolded state when it reaches a relatively large workspace, and begin using the device.

[0072] Another possible use case scenario is to take advantage of the characteristic of the Smooth Link mechanism, which allows linear movement restricted to one direction (longitudinal direction), and use it in a device for position adjustment.

[0073] In the above sections B and C, we have described an embodiment in which the present invention is applied to a force measurement device for a surgical tool device, but a device equipped with a SAW link mechanism can also be used for measurements other than force measurement. For example, instead of the treatment tool 101, a measurement device such as a measurement probe, a camera, an IMU (Inertial Measurement Unit) sensor, or a temperature sensor may be mounted at the distal end of the surgical tool device 100. Then, with the SAW link mechanism in a retracted state, the device can be inserted into a working space such as a surgical site through a narrow hole or gap, and the linear motion of the SAW link mechanism can then bring the measurement device close to the measurement target.

[0074] E. Surgical System This section E describes a surgical system that uses the surgical tool device 100 according to the present disclosure. However, the surgical system is a leader-follower system. The surgical system 1700 is a leader-follower system, in which a user such as a surgeon operates on the leader side, and on the follower side, surgery is performed by controlling the drive of the robot according to the user's operation (however, as will be described later, this may also include automatic or autonomous robot drive on the follower side). Purposes of incorporating robotics technology into a surgical system include suppressing the surgeon's hand tremors, providing operational support, accommodating differences in skill between surgeons, and performing surgery remotely.

[0075] 17 shows an example of a schematic functional configuration of a surgical system 2000. The surgical system 2000 is a leader-follower system and includes a leader device 2010, which is used by a user such as a surgeon to instruct the operation of a surgical tool, and a follower device 2020, which drives the surgical tool in accordance with instructions from the leader device 2010. The leader device 2010 and the follower device 2020 are capable of bidirectional communication via a transmission path 2030. Between the leader device 2010 and the follower device 2020, bilateral control is performed using bidirectional communication so that the displacement amount and force correspond to each other.

[0076] The reader device 2010 includes a reader-side control unit 2111, an input unit 2112, a presentation unit 2113, and a reader-side communication unit 2114. The reader device 2010 operates under the overall control of the reader-side control unit 2111.

[0077] The input unit 2112 is used by a user such as a surgeon to remotely operate the surgical robot 2122 on the follower device 2020 side and the surgical instrument device 100 supported by the surgical robot 2122. The input unit 2112 is configured, for example, with a manipulator that can perform operation with three translational degrees of freedom for instructing translational movement of the surgical instrument device 100 supported at the distal end by the surgical robot 2122, three rotational degrees of freedom for instructing a change in posture of the surgical instrument device 100, and one degree of freedom for instructing the operation of the treatment tool 101 attached to the surgical instrument device 100 and the state transition (stored state ⇔ deployed state) of the force sensor unit 102. For example, the input unit 2112 may further include a joystick, a foot switch, or another input device for performing 3D operations on a screen.

[0078] The presentation unit 2113 presents (feeds back) to the user information related to the surgery being performed in the follower device 2020, mainly based on sensor information acquired by a sensor unit 2123 (described later) on the follower device 2020 side. For example, when an operative field image captured by a camera is sent from the follower device 2020 with low latency, the presentation unit 2113 displays the operative field image in real time on the screen as a visual presentation function.

[0079] The presentation unit 2113 may have a force feedback function incorporated and implemented in the input unit 2112. The force feedback function is realized, for example, by driving at least some of the axes of a manipulator (described above) having three translational degrees of freedom, a rotational degree of freedom, and a grasping degree of freedom with a motor. When the force sensor unit 102 incorporated in the surgical tool device 100 on the follower device 2020 side is equipped with a function for measuring forces such as external forces and moments acting on the treatment tool 101 and force feedback information is sent from the follower device 2020 with low latency, the presentation unit 2113 provides force feedback to the user in real time by driving the motor of the manipulator. Furthermore, the presentation unit 2113 may present the physical quantity of force to the user not only directly (or in addition to directly presenting the physical quantity of force) but also via visual information displayed on a display or audio output from a speaker (which may be sound effects, audio guidance, etc.).

[0080] The leader-side communication unit 2114 performs processing for transmitting and receiving signals to and from the follower device 2020 via the transmission path 2030 under the control of the leader-side control unit 2111. For example, if the transmission path 2030 is made of optical fiber, the leader-side communication unit 2114 includes an electrical-to-optical conversion unit that converts electrical signals sent from the leader device 2010 into optical signals, and an optical-to-electrical conversion unit that converts optical signals received from the transmission path 2030 into electrical signals. The leader-side communication unit 2114 transfers operation commands for the surgical robot 2122 input by the user (operator) via the operation input device 2012 to the follower device 2020 via the transmission path 2030. The leader-side communication unit 2114 also receives sensor information sent from the follower device 2020 via the transmission path 2030.

[0081] On the other hand, the follower device 2020 includes a follower-side control unit 2121, a surgical robot 2122, a sensor unit 2123, and a follower-side communication unit 2124. The follower device 2020 operates in accordance with instructions from the leader device 2010 under the overall control of the follower-side control unit 2121.

[0082] The surgical robot 2122 is equipped with, for example, a serial link mechanism, and has three translational degrees of freedom for translating the surgical tool device 100 supported at its distal end, and three rotational degrees of freedom for changing the posture of the surgical tool device 100. Since the present disclosure is not limited to a specific configuration of the surgical robot 2122, detailed description thereof will be omitted in this specification. The follower-side control unit 2121 interprets operation commands sent from the leader device 2010 via the transmission path 2030, converts them into drive signals for the drive axes for operating the surgical tool device 100, and outputs the signals to control the drive of the surgical robot 2122.

[0083] In addition to leader-follower operation in response to user operation input, the surgical robot 2122 may also be configured to perform automatic or autonomous operation without human intervention based on position measurement values ​​and force measurement values. For example, the surgical robot 2122 may have a leader-follower operation mode in which it operates following user operation input on the leader device 2010 side, and an automatic or autonomous operation mode. Furthermore, operations other than therapeutic treatment, such as surgical tool replacement, may be performed by the surgical robot 2122 through automatic or autonomous operation.

[0084] The sensor unit 2123 is equipped with a plurality of sensors that detect the status of the surgical robot 2122 itself and the status of the affected area during surgery, and is further equipped with an interface for acquiring sensor information from various sensor devices installed in the operating room. For example, the sensor unit 2123 includes the force sensor unit 102 incorporated in the surgical tool device 100. The sensor unit 2123 is also equipped with an interface for acquiring an observation image of the affected area taken by a camera (not shown).

[0085] The follower-side communication unit 2124 performs transmission and reception processing with the leader device 2010 via the transmission path 2030 under the control of the follower-side control unit 2121. For example, if the transmission path 2030 is made of optical fiber, the follower-side communication unit 2124 includes an electrical-to-optical conversion unit that converts an electrical signal sent from the follower device 2020 into an optical signal, and an optical-to-electrical conversion unit that converts an optical signal received from the transmission path 2030 into an electrical signal.

[0086] The follower-side communication unit 2124 transfers the force data of the treatment tool 101 acquired by the force sensor unit 102 and the surgical field image captured by the camera to the leader device 2010 via the transmission path 2030. The follower-side communication unit 2124 also receives, via the transmission path 2030, operation commands for the surgical robot 2122 sent from the leader device 2010.

[0087] F. Summary Finally, the features of the force measuring device according to the present disclosure will be summarized.

[0088] The force measuring device according to the present disclosure has a configuration in which a strain body incorporated in a Spherical link mechanism is deformed to improve the aspect ratio (i.e., rigidity anisotropy is eliminated). The force measuring device transitions between a stored state with a small diameter and a deployed state with an increased diameter through the operation of the Spherical link mechanism, making it possible to adjust the measurement sensitivity in the longitudinal direction of the strain body and in the direction perpendicular thereto.

[0089] The force measuring device of the present disclosure can transition to a stored state with a small diameter by straightening out each folding structure that makes up the Saras link mechanism. In this stored state, the device can be inserted into a working space (e.g., an eyeball) by passing through narrow holes or gaps, and can then transition to an unfolded state, enabling force measurements with an improved aspect ratio.

[0090] The use of the device using the self-aligning link mechanism according to the present disclosure is not limited to force measurement. For example, the device using the self-aligning link mechanism can be equipped with a camera, a probe, an IC, various other sensors, and the like, and can be used for purposes other than force measurement.

[0091] The Sarasu link mechanism used in the present disclosure is constructed by connecting the upper and lower ends of multiple folding structures consisting of a set of flat plates with a hinge in the center, and some of the flat plates of each folding structure include a strain-generating body, and the strain sensor is attached by gluing it to the flat portion of the strain-generating body, which simplifies the process of attaching the strain sensor.

[0092] It should be noted that the effects described in this specification are merely examples, and the effects brought about by the present disclosure are not limited thereto. Furthermore, the present disclosure may have additional effects in addition to the effects described above. Further objects, features, and advantages of the present disclosure will become apparent from a more detailed description based on the embodiments described in this specification and the accompanying drawings.

[0093] The present disclosure has been described in detail above with reference to specific embodiments. However, the present disclosure should not be construed as being limited to the above-described embodiments, and it is obvious that those skilled in the art can modify or substitute the embodiments without departing from the spirit of the present disclosure. Furthermore, the effects described in this specification are merely examples, and the effects brought about by the present disclosure are not limited thereto, and additional effects not described in this specification may exist.

[0094] Although the present specification has mainly described embodiments in which the present disclosure is applied to a surgical tool device for retinal surgery, the gist of the present disclosure is not limited thereto. When used in a narrow working space such as retinal surgery, a small and thin-diameter sarcoma link mechanism can be fabricated using a folding structure in which a rigid body is bonded to a plastic film. On the other hand, when used in a relatively large space, the sarcoma link mechanism can be fabricated using a folding structure made of general mechanical parts, such as metal plates connected together by bearings.

[0095] Furthermore, although the present specification has focused on embodiments relating to force measurement devices, the scope of application of the present disclosure can be expanded to devices for uses other than force measurement. For example, instead of a treatment tool, a measurement device such as a measurement probe, a camera, an IMU sensor, or a temperature sensor may be mounted at the distal end of the surgical device. The device can then be inserted into a working space such as a surgical site by passing through a narrow hole or gap with the retracted link mechanism, and the linear motion of the retracted link mechanism can be used to move the measurement device closer to the measurement target.

[0096] In short, the present disclosure has been described in the form of examples, and the contents of the specification should not be interpreted as limiting. To determine the gist of the present disclosure, the claims should be taken into consideration.

[0097] The present disclosure may also be configured as follows.

[0098] (1) A force measuring device capable of measuring multi-axial forces including the first axis and a second axis perpendicular to the first axis, the force measuring device comprising: a mechanical part having a first state in which a diameter from a central axis parallel to the direction of a first axis is smaller than a predetermined value, and a second state in which the diameter from the central axis is larger than the predetermined value; and a strain sensor attached to a strain-generating element included in the mechanical part.

[0099] (2) The force measuring device according to (1), wherein the mechanical part is elongated in the direction of the first axis in the first state, and deforms in a direction increasing in the direction of a second axis perpendicular to the first axis in the second state.

[0100] (3) The mechanism is configured by arranging a plurality of folding structures each consisting of a set of flat plates with a hinge in the center, with the hinge facing the direction of the second axis, and connecting the upper and lower ends of each folding structure to an upper end block and a lower end block, respectively, and has a first state in which the upper end block and the lower end block are separated and each folding structure extends straight, thereby reducing its diameter, and a second state in which the upper end block and the lower end block are brought closer together and each hinge moves in the direction of the second axis when each folding structure is bent, thereby increasing its diameter, a force measuring device described in any one of (1) or (2) above.

[0101] (4) The force measuring device according to (3), wherein a flat plate of a part of each folded structure includes the strain element, and the strain sensor is attached by bonding to a flat portion of the strain element.

[0102] (5) The force measuring device according to any one of (1) to (4), wherein the strain sensor is an FBG sensor, a strain gauge, or a capacitive strain sensor.

[0103] (6) A surgical tool device comprising: a treatment tool; a mechanical unit that has a first state in which a diameter from a central axis parallel to a direction of a first axis is smaller than a predetermined value and a second state in which the diameter from the central axis is larger than the predetermined value and supports the treatment tool; and a strain sensor attached to a strain generating body included in the mechanical unit.

[0104] (7) The mechanical unit is configured by arranging a plurality of folding structures each consisting of a set of flat plates with a hinge in the center so that the hinge faces in the direction of a second axis perpendicular to the first axis, and connecting the upper and lower ends of each folding structure to an upper end block and a lower end block, respectively, and has a stored state in which the upper end block and the lower end block are separated and each folding structure extends straight, thereby becoming narrow in diameter, and an expanded state in which the upper end block and the lower end block are brought close to each other and each folding structure is bent, thereby causing each hinge to move in the direction of the second axis, thereby increasing the diameter; and after the mechanical unit is put into the stored state and passed through a small hole or gap, the mechanical unit is put into the expanded state and multi-axis force measurement including the first axis and the second axis is performed using the strain sensor, the surgical tool device described in (6) above.

[0105] (8) The surgical tool device according to (7), wherein a flat plate of a part of each folding structure includes the strain element, and the strain sensor is attached by bonding to the flat portion of the strain element.

[0106] (9) A surgical system comprising a leader device and a follower device, wherein the follower device comprises a robot that operates a surgical tool device, the surgical tool device comprises a treatment tool, a mechanism that supports the treatment tool, and a strain sensor attached to a strain-generating body included in the mechanism, the mechanism has a first state in which a diameter from a central axis parallel to a direction of a first axis is smaller than a predetermined value, and a second state in which the diameter from the central axis is larger than the predetermined value, and the leader device comprises an operation user interface that inputs instructions for an operation amount to the robot, and a presentation unit that presents a force sensation based on an external force measured by the strain sensor.

[0107] (10) The mechanism unit is configured by arranging a plurality of folding structures each consisting of a set of flat plates with a hinge in the center so that the hinge faces in the direction of a second axis perpendicular to the first axis, and connecting the upper and lower ends of each folding structure to an upper end block and a lower end block, respectively, and has a stored state in which the upper end block and the lower end block are separated and each folding structure extends straight, thereby becoming narrow in diameter, and an expanded state in which the upper end block and the lower end block are brought close to each other and each folding structure is bent, thereby causing each hinge to move in the direction of the second axis, thereby increasing the diameter; and after putting the mechanism unit into the stored state and passing it through a small hole or gap, putting the mechanism unit into the expanded state and performing multi-axis force measurement including the first axis and the second axis using the strain sensor, the surgical system described in (9) above.

[0108] (11) The surgical system described in (10) above, wherein a flat plate of a part of each folding structure includes the strain element, and the strain sensor is attached by adhesive to the flat portion of the strain element.

[0109] DESCRIPTION OF SYMBOLS 100... surgical tool device, 101... treatment tool, 102... force sensor unit, 103... support unit, 111... trocar, 401... upper end block, 402... lower end block, 501-504... folding structure, 511-514... strain body, 521-524... strain sensor, 531-534... adhesive, 2000 medical robot system, 2010... leader device, 2011... monitor, 2012... operation input device, 2020... follower device, 2021... first robot device, 2022... second robot device, 2023... microscope, 2030... transmission path, 2111... leader side control unit, 2112... input unit, 2113... presentation unit, 2114... leader side communication unit, 2121... follower side control unit, 2122... surgical robot 2123: Sensor unit, 2124: Follower side communication unit

Claims

1. A force measuring device capable of measuring multi-axial forces including the first axis and a second axis perpendicular to the first axis, comprising: a mechanical unit having a first state in which the diameter from a central axis parallel to the direction of a first axis is smaller than a predetermined value, and a second state in which the diameter from said central axis is larger than said predetermined value; and a strain sensor attached to a strain-generating element included in said mechanical unit.

2. The force measuring device according to claim 1, wherein the mechanical part is elongated in the direction of the first axis in the first state, and deforms in a direction increasing in the direction of a second axis perpendicular to the first axis in the second state.

3. The force measuring device described in claim 1, wherein the mechanism is configured by arranging a plurality of folding structures each consisting of a set of flat plates with a hinge in the center so that the hinge faces the direction of the second axis, and connecting the upper and lower ends of each folding structure to an upper end block and a lower end block, respectively, and has a first state in which the upper end block and the lower end block are separated and each folding structure extends straight, thereby reducing its diameter, and a second state in which the upper end block and the lower end block are brought closer together and each hinge moves in the direction of the second axis as each folding structure bends, thereby increasing its diameter.

4. A force measuring device according to claim 3, wherein a flat plate in a portion of each folded structure includes the strain element, and the strain sensor is attached by adhesive to a flat portion of the strain element.

5. The force measuring device according to claim 1, wherein the strain sensor is an FBG sensor, a strain gauge, or a capacitive strain sensor.

6. A surgical tool device comprising: a treatment tool; a mechanical unit that supports the treatment tool and has a first state in which a diameter from a central axis parallel to the direction of a first axis is smaller than a predetermined value and a second state in which the diameter from the central axis is larger than the predetermined value; and a strain sensor attached to a strain generating body included in the mechanical unit.

7. The surgical tool device described in claim 6, wherein the mechanism is configured by arranging a plurality of folding structures each consisting of a set of flat plates with a hinge in the center so that the hinge faces the direction of a second axis perpendicular to the first axis, and connecting the upper and lower ends of each folding structure to an upper end block and a lower end block, respectively, and has a stored state in which the upper end block and the lower end block are separated and each folding structure extends straight, thereby reducing its diameter, and an expanded state in which the upper end block and the lower end block are brought close to each other and each folding structure is bent, thereby causing each hinge to move in the direction of the second axis, thereby increasing its diameter; and wherein the mechanism is stored in the stored state, passed through a small hole or gap, and then the mechanism is expanded and multi-axis force measurement including the first axis and the second axis is performed using the strain sensor.

8. The surgical tool device according to claim 7, wherein a flat plate in a portion of each folding structure includes the strain element, and the strain sensor is attached by adhesive to the flat portion of the strain element.

9. A surgical system comprising a leader device and a follower device, wherein the follower device comprises a robot that operates a surgical tool device, the surgical tool device comprises a treatment tool, a mechanical unit that supports the treatment tool, and a strain sensor attached to a strain-generating body included in the mechanical unit, the mechanical unit having a first state in which a diameter from a central axis parallel to the direction of a first axis is smaller than a predetermined value, and a second state in which the diameter from the central axis is larger than the predetermined value, and the leader device comprises an operation user interface unit that inputs instructions for the amount of operation for the robot, and a presentation unit that presents a force sensation based on an external force measured by the strain sensor.

10. The surgical system described in claim 9, wherein the mechanism is configured by arranging a plurality of folding structures each consisting of a set of flat plates with a hinge in the center so that the hinge faces in the direction of a second axis perpendicular to the first axis, and connecting the upper and lower ends of each folding structure to an upper end block and a lower end block, respectively, and has a stored state in which the upper end block and the lower end block are separated and each folding structure extends straight, thereby reducing its diameter, and an expanded state in which the upper end block and the lower end block are brought close to each other and each folding structure is bent, thereby causing each hinge to move in the direction of the second axis, thereby increasing its diameter; and wherein the mechanism is stored in the stored state, passed through a small hole or gap, and then the mechanism is expanded and multi-axis force measurement including the first axis and the second axis is performed using the strain sensor.

11. The surgical system according to claim 10, wherein a flat plate in a portion of each folded structure includes the strain element, and the strain sensor is attached by adhesive to the flat portion of the strain element.

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