Closed loop wire drive actuated longitudinal automatic differential compensation device and method

Abstract

The application relates to a closed-loop wire transmission driving longitudinal automatic differential compensation device and method, and belongs to the technical field of surgical robots. The device mainly comprises a base, a differential unit fixed on the base, a guide unit fixed on the base, and a rope unit for connecting the differential unit and a closed-loop wire transmission driving object. The differential unit is connected with the closed-loop wire transmission driving object through the guide unit and the rope unit. The closed-loop wire transmission driving longitudinal automatic differential compensation device provided by the application realizes automatic, real-time and longitudinal differential compensation of the tightness of a steel wire rope during clamping of a surgical instrument through the synergistic effect of the differential unit (spline shaft, drum, spring, etc.), the guide unit and the rope unit, so that the control precision, response speed and operation safety of the surgical robot are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of surgical robot technology, specifically relating to a closed-loop wire drive longitudinal automatic differential compensation device and method. Background Technology

[0002] Surgical instruments are one of the key tools in surgical robots. Currently, closed-loop wire drive is mainly used to drive the movement of surgical instruments. This closed-loop wire drive method has technical advantages such as light weight, low noise, low cost, and easy integration. The surgical instrument forceps head is driven by closed-loop wire drive to perform multi-degree-of-freedom movements, including rotation, pitch, swing, opening and closing, and clamping, such as… Figure 1 As shown.

[0003] During the process of controlling surgical instruments to clamp suture needles or tissue, the characteristics of closed-loop wire drive cause each instrument's clamping head to exhibit a phenomenon where the tight side tightens and the loose side disengages from the winding groove, and this phenomenon gradually worsens with increased use. This phenomenon leads to control lag in the process of controlling the surgical instruments from clamping to opening, affecting the control accuracy of the surgical robot and posing potential operational safety issues.

[0004] While existing technologies can address the aforementioned problems to some extent, their structural limitations hinder their clinical application. For example, Chinese patent CN 112545658 A discloses a surgical instrument, a manipulator, and a surgical robot. The surgical instrument includes an end effector, a drive unit, and cables. The drive unit is configured to drive the end effector via the cables. The cables include a first pair of cables and a second pair of cables for driving the end effector to perform yaw motion, and a third pair of cables for driving the end effector to perform pitch motion. Since yaw and pitch motions are orthogonal, the third pair of cables is coupled to the first and second pairs of cables on the end effector. The drive unit has a decoupling mechanism to release this coupling. The decoupling mechanism includes a main decoupling member, a secondary decoupling member, and decoupling cables. The main decoupling member and the secondary decoupling member are connected via the decoupling cables. The main decoupling member rotates coaxially with the drive unit and drives the secondary decoupling member to slide relative to the main body via the decoupling cables. This patented surgical instrument requires an additional drive unit, affecting the instrument's drive layout. Summary of the Invention

[0005] To address the problem that existing technologies lack a differential compensation mechanism, which leads to the phenomenon of tight sides tightening and loose sides detaching from the winding groove during tissue clamping and suture needle clamping, resulting in control lag in the control process of surgical instruments from clamping to opening, and thus affecting the control accuracy of surgical robots, this invention provides a closed-loop wire drive longitudinal automatic differential compensation device and method.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows:

[0007] This invention provides a closed-loop wire drive longitudinal automatic differential compensation device, comprising:

[0008] Base;

[0009] Differential unit fixed on base;

[0010] Guide unit fixed on the base;

[0011] A rope unit is used to connect a differential unit to a closed-loop wire drive drive object. The differential unit is connected to the closed-loop wire drive drive object through a guide unit and a rope unit.

[0012] Furthermore, the differential unit includes a splined shaft, an upper drum, a lower drum, a splined nut, and a spring; the lower end of the splined shaft is fixed to the base, and the surface of the splined shaft is provided with a longitudinal sliding groove, with a lower limiting ridge at the middle position; the upper outer wall of the lower drum is provided with a threaded hole, and the lower outer wall of the lower drum is provided with a second winding groove for winding the rope unit, and the inner wall of the lower drum is provided with a flat key; the outer wall of the upper drum is provided with a first winding groove for winding the rope unit; the inner wall of the splined nut is provided with a cylindrical protrusion, one side of the upper end of the outer wall of the splined nut is provided with a keyway, and the other side of the upper end of the outer wall of the splined nut is provided with a countersunk hole; the lower end of the outer wall of the splined nut is provided with an upper limiting ridge.

[0013] Furthermore, the upper drum is fixed to the upper end of the spline shaft by a flat key on its inner wall; the spline nut is fitted on the spline shaft, and the cylindrical protrusion cooperates with the sliding groove to ensure that the spline nut can move along the axial direction of the spline shaft, while also restricting the relative circumferential movement between the two.

[0014] Furthermore, the upper end of the spring is fixed to the upper limit edge of the spline nut, and the upper end ring of the spring cooperates with the upper limit edge to limit the upper end of the spring; the lower end of the spring is fixed to the lower limit edge of the spline shaft, and the lower end ring of the spring cooperates with the lower limit edge to limit the lower end of the spring.

[0015] Furthermore, the lower drum is fitted onto the upper end of the spline nut, and the threaded hole (231) is used to install the set screw. The set screw and the countersunk hole cooperate to realize the circumferential limit of the lower drum and the spline nut. The flat key and the keyway cooperate to realize the circumferential movement limit of the lower drum and the spline nut.

[0016] Furthermore, the guide unit is fixedly connected to the base via a pulley shaft, and there are two guide units, both of which are implemented using pulleys.

[0017] Furthermore, the rope unit is implemented using two ropes. One end of one rope is wound around and fixed to the lower drum in the differential unit, and the other end is wound around the first guide unit and fixedly connected to one end of the closed-loop wire drive object. One end of the other rope is wound around and fixed to the lower drum in the differential unit, and the other end is wound around the second guide unit and fixedly connected to the other end of the closed-loop wire drive object.

[0018] Furthermore, the rope is made of various types of braided steel wire rope or tungsten wire rope.

[0019] Furthermore, the closed-loop wire drive is used to drive surgical instruments.

[0020] Furthermore, the surgical instrument is a needle holder or tissue forceps.

[0021] The present invention also provides a method for automatic differential compensation in the longitudinal direction of a closed-loop wire drive, which employs the aforementioned automatic differential compensation device for a closed-loop wire drive, and specifically includes the following steps:

[0022] (1) Assemble the device;

[0023] (2) When there is no clamping force, i.e. there is no object to apply force, both the slack side wire rope and the tight side wire rope need to be pre-tensioned, and the force applied downward by the lower drum to the spring. , F is the helix angle of the spiral line of the drum wheel groove. t This refers to the preload of the wire rope.

[0024] In the initial state, i.e., without clamping force, the lower drum compresses the spring downwards under its own weight, and the preload F of the wire rope is adjusted accordingly. t This allows for control of the downward force applied to the spring by the lower drum;

[0025] (3) When there is clamping force, i.e., when there is an object applying force, the tight side wire rope is tightened and the loose side wire rope is relaxed to less than the preload F. t At this time, the tight-side steel wire rope pulls the lower drum upward under the action of external force, thereby stretching the spring and realizing differential compensation.

[0026] The beneficial effects of this invention are:

[0027] The present invention provides a closed-loop wire drive longitudinal automatic differential compensation device. Through the synergistic effect of differential unit (spline shaft, drum wheel, spring, etc.) with guide unit and rope unit, it realizes automatic, real-time, longitudinal differential compensation of wire rope tension during surgical instrument clamping, thereby significantly improving the control accuracy, response speed and operation safety of surgical robot.

[0028] 1. Effectively solves the problem of "tight edges tightening and loose edges detaching";

[0029] This invention uses the cooperation of springs and drums to automatically adjust the length of the slack rope during clamping, preventing it from detaching from the winding groove and keeping the transmission system in a taut and controllable state at all times.

[0030] 2. Eliminate control lag and improve motion accuracy;

[0031] This invention can compensate for differences in rope extension and retraction in real time, reduce the delay from clamping to opening action, and improve the consistency of motion response and positioning accuracy of surgical instruments.

[0032] 3. Compact structure, no additional drive required;

[0033] In this invention, the differential unit is integrated into the base, eliminating the need for external motors or actuators and not affecting the original instrument layout, making it suitable for space-constrained surgical robot environments.

[0034] 4. Adaptive force compensation protects the transmission system;

[0035] In this invention, the spring automatically adjusts the position of the drum according to the clamping force to achieve dynamic force balance and reduce the risk of rope wear or breakage caused by excessive tightness or looseness.

[0036] 5. Applicable to a variety of surgical instruments;

[0037] This invention is compatible with various closed-loop wire-driven surgical instruments such as needle holders and tissue forceps, and is highly versatile, facilitating system integration and standardized design.

[0038] 6. Improve surgical safety and reliability;

[0039] This invention enhances the stability and safety of surgical robots in delicate operations (such as suturing and tissue clamping) by reducing control errors and transmission failure risks. Attached Figure Description

[0040] Figure 1 This is a schematic diagram illustrating the multi-degree-of-freedom motion of a surgical instrument forceps head driven by a closed-loop wire transmission.

[0041] Figure 2 This is a schematic diagram of a closed-loop wire drive longitudinal automatic differential compensation device provided by the present invention.

[0042] Figure 3 This is a schematic diagram of the differential unit.

[0043] Figure 4 This is a schematic diagram showing the positional relationship between the differential unit, the guide unit, and the rope unit.

[0044] Figure 5 This is a schematic diagram of the spline shaft.

[0045] Figure 6 This is a schematic diagram of the lower drum.

[0046] Figure 7 This is a schematic diagram of the spline motherboard.

[0047] Figure 8 The schematic diagram shows a closed-loop wire drive longitudinal automatic differential compensation method provided by the present invention.

[0048] Figure 9 A simplified model diagram of a wire rope support groove for closed-loop wire-driven surgical instruments.

[0049] In the diagram, 10 - differential compensation mechanism, 20 - differential unit, 21 - spline shaft, 211 - slide groove, 212 - limiting edge, 22 - upper drum, 23 - lower drum, 231 - threaded hole, 232 - second winding groove, 233 - flat key, 24 - spline nut, 241 - cylindrical protrusion, 242 - keyway, 243 - countersunk hole, 244 - upper limiting edge; 25 - spring, 30 - guide unit, 40 - rope unit, 50 - base, 60 - surgical instrument. Detailed Implementation

[0050] The present invention will be further described in detail below with reference to the accompanying drawings.

[0051] In a first aspect, the present invention provides a closed-loop wire drive longitudinal automatic differential compensation device.

[0052] like Figure 2 As shown, the present invention provides a closed-loop wire drive longitudinal automatic differential compensation device, mainly implemented by a differential compensation mechanism 10. The differential compensation mechanism 10 mainly includes a differential unit 20, a guide unit 30, a rope unit 40, and a base 50. The differential unit 20, the guide unit 30, and the closed-loop wire drive object are all fixed on the base 50. The rope unit 40 is used to connect the differential unit 20 and the closed-loop wire drive object. The differential unit 20 is connected to the closed-loop wire drive object through the guide unit 30 and the rope unit 40. The number of differential units 20 is at least one, and can be set according to actual needs.

[0053] like Figures 3 to 7As shown, the differential unit 20 mainly consists of a splined shaft 21, an upper drum 22, a lower drum 23, a splined nut 24, and a spring 25. The lower end of the spline shaft 21 is fixed on the base 50. The surface of the spline shaft 21 is provided with a longitudinal sliding groove 211, and a lower limit ridge 212 is provided in the middle position. The upper outer wall of the lower drum 23 is provided with a threaded hole 231, and the lower outer wall of the lower drum 23 is provided with a second winding groove 232 for winding the rope unit 40. The inner wall of the lower drum 23 is provided with a flat key 233. The upper drum 22 is similar in structure to the lower drum 23, except that the upper drum 22 is provided with a boss at the upper end, and the outer wall of the upper drum 22 is provided with a first winding groove for winding the rope unit 40. The inner wall of the spline nut 24 is provided with a cylindrical protrusion 241, one side of the upper end of the outer wall of the spline nut 24 is provided with a keyway 242, and the other side of the upper end of the outer wall of the spline nut 24 is provided with a countersunk hole 243. The lower end of the outer wall of the spline nut 24 is provided with an upper limit ridge 244. The positional connection between them is as follows: the upper drum 22 is fixed to the upper end of the spline shaft 21 by a flat key on its inner wall; the spline nut 24 is fitted on the spline shaft 21, and the cylindrical protrusion 241 cooperates with the groove 211 to ensure that the spline nut 24 can move along the axial direction of the spline shaft 21, while also limiting the relative circumferential movement between the two; the upper end of the spring 25 is fixed to the upper limit ridge 244 of the spline nut 24, and the upper ring of the spring 25 cooperates with the upper limit ridge 244 to realize the spring-loaded movement. The upper end of the spring 25 is limited; the lower end of the spring 25 is fixed on the lower limit edge 212 of the spline shaft 21, and the lower end ring of the spring 25 cooperates with the lower limit edge 212 to limit the lower end of the spring 25; the lower drum 23 is fitted on the upper end of the spline nut 24, the threaded hole 231 is used to install the set screw, the set screw cooperates with the countersunk hole 243 to realize the circumferential limitation of the lower drum 23 and the spline nut 24, and the flat key 233 cooperates with the keyway 242 to realize the circumferential movement limitation of the lower drum 23 and the spline nut 24.

[0054] In this invention, there are two guide units 30. The guide unit 30 can be a pulley of various sizes and configurations, which is fixedly connected to the base 50 through a pulley axle, and the pulley can rotate relative to the base 50 and the pulley axle.

[0055] In this invention, the closed-loop wire drive is a surgical instrument 60, which can be a needle holder, tissue forceps, or other existing technology, but is not limited to these.

[0056] In this invention, the rope unit 40 is mainly implemented using two ropes. One end of one rope is wrapped around and fixed to the lower drum 23 in the differential unit 20, and the other end is wrapped around the first guide unit 30 and then fixedly connected to the first clamping end of the surgical instrument 60. One end of the other rope is wrapped around and fixed to the lower drum 23 in the differential unit 20, and the other end is wrapped around the second guide unit 30 and then fixedly connected to the second clamping end of the surgical instrument 60.

[0057] In this invention, the rope can be made of various types of braided steel wire rope or tungsten wire rope, but is not limited to these, and the outer diameter is usually no more than 0.5 mm.

[0058] In this invention, the base 50 has a through hole at its center for the rope unit 40 to pass through.

[0059] Secondly, the present invention provides a closed-loop wire drive longitudinal automatic differential compensation method, which is mainly implemented by a closed-loop wire drive longitudinal automatic differential compensation device provided in the first aspect.

[0060] The present invention provides a closed-loop wire drive longitudinal automatic differential compensation method, which specifically includes the following steps:

[0061] (1) Assemble the device according to the instructions in the first aspect;

[0062] (2) When there is no clamping force, i.e. there is no object applying force (referring to the clamped suture needle or tissue), both the slack-side wire rope and the tight-side wire rope need to be pre-tensioned. The simplified mechanical model is as follows: Figure 8 As shown, D is the diameter of the drum. F is the helix angle of the spiral line of the drum wheel groove. t F is the preload of the wire rope, and F is the force exerted downwards by the lower drum 23 on the spring 25. .

[0063] In the initial state, i.e., without clamping force, the lower drum 23 compresses the spring 25 downwards by its own weight. This can be adjusted by changing the preload F of the wire rope. t This allows for control of the downward force applied by the lower drum 23 to the spring 25.

[0064] (3) When there is clamping force, i.e., when there is an object applying force, the tight side wire rope is tightened and the loose side wire rope is relaxed to less than the preload F. t At this time, the tight-side steel wire rope pulls the lower drum 23 upward under the action of external force, thereby stretching the spring 25 and realizing differential compensation.

[0065] This invention solves the problems of "tight side being tightened and loose side detaching from the winding groove" and "control hysteresis".

[0066] Among them, the simplified model of the wire rope support groove for closed-loop wire-driven surgical instruments is as follows: Figure 9 As shown, the specific formula for calculating the theoretical elongation of a slack-side wire rope is as follows:

[0067]

[0068] In the formula, This represents the theoretical elongation of the slack-side wire rope. For the required clamping force, The distance from the center of the clamping object (i.e., the object to which force is applied) to the center axis of the clamp head. The length of the wire rope. The elastic modulus of the steel wire rope. Let be the radius of the surgical instrument forceps head. The theoretical elongation of the slack wire rope can be calculated using the above formula, and then a suitable spring 25 can be selected based on the theoretical elongation of the slack wire rope.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A closed-loop wire drive driven longitudinal automatic differential compensation device, characterized in that, include: Base (50); Differential unit (20) fixed on base (50); Guide unit (30) fixed on base (50); The differential unit (20) is used to connect the rope unit (40) to the closed-loop wire drive object, the differential unit (20) being connected to the closed-loop wire drive object via the guide unit (30) and the rope unit (40).

2. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 1, characterized in that, The differential unit (20) includes a spline shaft (21), an upper drum (22), a lower drum (23), a spline nut (24), and a spring (25); the lower end of the spline shaft (21) is fixed on the base (50), and the surface of the spline shaft (21) is provided with a longitudinal sliding groove (211), and a lower limiting ridge (212) is provided in the middle position; the upper outer wall of the lower drum (23) is provided with a threaded hole (231), and the lower outer wall of the lower drum (23) is provided with a second winding groove (232). For winding the rope unit (40), a flat key (233) is provided on the inner wall of the lower drum (23); a first winding groove is provided on the outer wall of the upper drum (22) for winding the rope unit (40); a cylindrical protrusion (241) is provided on the inner wall of the spline nut (24); a keyway (242) is provided on one side of the upper end of the outer wall of the spline nut (24); a countersunk hole (243) is provided on the other side of the upper end of the outer wall of the spline nut (24); an upper limit ridge (244) is provided at the lower end of the outer wall of the spline nut (24).

3. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 2, characterized in that, The upper drum (22) is fixed to the upper end of the spline shaft (21) by a flat key on its inner wall; the spline nut (24) is fitted on the spline shaft (21), and the cylindrical protrusion (241) cooperates with the slide groove (211) to ensure that the spline nut (24) can move along the axial direction of the spline shaft (21), while also restricting the relative circumferential movement of the two.

4. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 2, characterized in that, The upper end of the spring (25) is fixed on the upper limit edge (244) of the spline nut (24), and the upper end ring of the spring (25) cooperates with the upper limit edge (244) to limit the upper end of the spring (25); the lower end of the spring (25) is fixed on the lower limit edge (212) of the spline shaft (21), and the lower end ring of the spring (25) cooperates with the lower limit edge (212) to limit the lower end of the spring (25).

5. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 2, characterized in that, The lower drum (23) is fitted onto the upper end of the spline nut (24). The threaded hole (231) is used to install the set screw. The set screw and the countersunk hole (243) cooperate to realize the circumferential limit of the lower drum (23) and the spline nut (24). The flat key (233) and the keyway (242) cooperate to realize the circumferential movement limit of the lower drum (23) and the spline nut (24).

6. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 1, characterized in that, The guide unit (30) is fixedly connected to the base (50) via a pulley shaft. There are two guide units (30), both of which are implemented using pulleys.

7. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 1, characterized in that, The rope unit (40) is implemented using two ropes. One end of one rope is wound around and fixed to the lower drum (23) in the differential unit (20), and the other end is wound around the first guide unit (30) and then fixedly connected to one end of the closed-loop wire drive object. One end of the other rope is wound around and fixed to the lower drum (23) in the differential unit (20), and the other end is wound around the second guide unit (30) and then fixedly connected to the other end of the closed-loop wire drive object.

8. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 7, characterized in that, The ropes are made of various types of braided steel wire ropes or tungsten wire ropes.

9. The closed-loop wire drive longitudinal automatic differential compensation device according to claim 1, characterized in that, The closed-loop wire drive is a surgical instrument (60); the surgical instrument (60) is a needle holder or tissue forceps.

10. A method for automatic longitudinal differential compensation of a closed-loop wire drive driven by an automatic differential compensation device for a closed-loop wire drive as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) Assemble the device; (2) When there is no clamping force, i.e. there is no object to apply force, both the slack side wire rope and the tight side wire rope need to be pre-tightened, and the lower drum (23) applies downward force to the spring (25). , F is the helix angle of the spiral line of the drum wheel groove. t This refers to the preload of the wire rope. In the initial state, i.e., without clamping force, the lower drum (23) compresses the spring (25) downwards by its own weight, and the preload F of the wire rope is adjusted. t This enables control over the downward force exerted by the lower drum (23) on the spring (25); (3) When there is clamping force, i.e., when there is an object applying force, the tight side wire rope is tightened and the loose side wire rope is relaxed to less than the preload F. t At this time, the tight-side steel wire rope pulls the lower drum (23) upward under the action of external force, thereby stretching the spring (25) and realizing differential compensation.

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