A Concentric Tube Surgical Robot Based on a Universal Friction Wheel Driving Mechanism

Abstract

The present invention discloses a concentric tube surgical robot based on a universal friction wheel drive mechanism, which includes a bottom plate and a plurality of drive modules arranged on the bottom plate. The overall dimensions of the drive modules decrease or increase in sequence along the length direction of the bottom plate. The drive modules are in a nested structure. The drive module includes a first-direction drive group, a second-direction drive group and a circular tube. Anti-blocking rotation components are provided on both the first-direction drive group and the second-direction drive group. The anti-blocking rotation component includes a universal friction wheel sleeve and a plurality of friction wheels arranged on the universal friction wheel sleeve. The universal friction wheel sleeve is of a hollow structure. The friction wheels are in contact with the circular tube, and rolling friction cooperation is carried out by pressing the friction wheels against the circular tube. The drive mechanism of the present invention has a relatively fast movement speed and a light weight, has a modular design, is convenient for quick installation and disassembly of the modules, and this transmission method can achieve the effect of overload disengagement cooperation to realize anti-blocking rotation protection.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and particularly to a concentric tube surgical robot based on a universal friction wheel drive mechanism. Background Art

[0002] Nasopharyngeal carcinoma is a very common head and neck malignant tumor, usually occurring in the columnar epithelium of the nasal mucosa. If not surgically removed in time, tumor cells will spread everywhere. However, due to the small and slender nasal cavity structure, general surgical instruments are difficult to reach the nasopharynx, and it is also difficult to perform the resection of nasopharyngeal carcinoma lesion tissue and postoperative suture operation. A flexible, small and slender surgical robot that can reach the nasopharynx is of great significance. The driving performance and weight of its driving mechanism determine the control performance and weight of the entire concentric tube robot. Therefore, the driving mechanism is also an important research part of the concentric tube robot.

[0003] Existing concentric tube surgical robots mostly adopt the transmission scheme of screw rod guide rails, which have slow driving speed, insufficient movement speed at the end of the concentric tube, large weight, inconvenient installation, no anti-stall protection, and it is difficult to achieve modular design due to installation limitations for concentric tube robots using screw rod guide rails. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art solutions, the present invention provides a concentric tube surgical robot based on a universal friction wheel drive mechanism, which can effectively solve the problems raised in the background art.

[0005] The technical solution adopted by the present invention to solve its technical problems is:

[0006] A concentric tube surgical robot based on a universal friction wheel drive mechanism includes a bottom plate and a plurality of drive modules provided on the bottom plate. The overall dimensions of the drive modules decrease or increase sequentially along the length direction of the bottom plate, and the drive modules are in a nested structure;

[0007] The drive module includes a first-direction drive group, a second-direction drive group, and a circular tube with a concentric tube sleeved inside. The circular tube is connected to the first-direction drive group and the second-direction drive group. The first-direction drive group and the second-direction drive group are used for the movement and rotation of the circular tube;

[0008] Anti-stall components are provided on both the first-direction drive group and the second-direction drive group. The anti-stall component includes a universal friction wheel sleeve and a plurality of friction wheels provided on the universal friction wheel sleeve. The universal friction wheel sleeve is a hollow structure. The friction wheels are in contact with the circular tube, and the friction wheels are pressed against the circular tube for rolling friction cooperation;

[0009] The first-direction driving group and the second-direction driving group are arranged in opposite directions, and driving devices are connected to the bottoms of both the first-direction driving group and the second-direction driving group. The first-direction driving group and the second-direction driving group form perpendicular forces to each other on the circular tube through these driving devices.

[0010] Specifically, the first-direction driving group and the second-direction driving group are respectively arranged at two ends of the circular tube. The first-direction driving group and the second-direction driving group both include a synchronous pulley group, a bushing, a bearing, a base, and a motor box. The synchronous pulley group is connected to a universal friction wheel sleeve, and the universal friction wheel sleeve is provided with threaded holes for connecting friction wheels.

[0011] The base is fixedly connected to the motor box by bolts. The motor box is used to fix the driving device, and this driving device is a servo motor. The motor box is fixedly arranged on the bottom plate.

[0012] Specifically, the synchronous pulley group is sequentially connected to the bushing and the bearing, and the circular tube sequentially passes through the synchronous pulley group, the bushing, the bearing, and the universal friction wheel sleeve.

[0013] Specifically, the number of the friction wheels is 4 - 6, and the friction wheels are arranged at equal intervals along the circumference of the circular tube. The friction wheels rotate and move along the circumference of the circular tube through the driving device.

[0014] Specifically, the driving module further includes a first fixing member and several second fixing members. The first fixing member and the second fixing members are both used to fix the first-direction driving group and the second-direction driving group. The first fixing member is arranged between the second fixing members, and the second fixing members are symmetrically arranged at two ends of the circular tube.

[0015] Specifically, both the first fixing member and the second fixing members are composed of detachable bearing covers, and the bearing covers are fixed by bolts.

[0016] Specifically, the installation angle between the friction wheel and the central axis of the circular tube is 30 degrees - 60 degrees.

[0017] Specifically, the material of the circular tube is rubber. The diameters of the circular tubes arranged on the driving module increase or decrease sequentially along the length direction of the bottom plate, and the circular tubes can be sleeved with each other.

[0018] Specifically, the synchronous pulley group includes a set of gear discs and a transmission belt meshed with the gear discs. One of the gear discs is connected to the servo motor shaft.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The concentric tube surgical robot based on the universal friction wheel driving mechanism of the present invention has at least one of the following beneficial effects during use:

[0021] This driving method adopts a universal friction wheel driving mechanism, enabling the robot to have a lightweight and modular design, while also being able to increase the driving speed of the driving module. The integrally designed friction wheel sleeve can provide more stable frictional force and reserve a position for a screwdriver that is convenient for installation. The friction wheel sleeve is of a hollow structure, making it lighter in structure and capable of elastic deformation to provide a normal pressure. The installation part of the friction wheel undergoes a certain deformation to generate a pressing force. Compared with the pressing force generated by a spring, the normal pressure provided by this integral design is more stable, and it also ensures a more stable pressing fit and driving. The front and rear friction wheels are of a symmetrical structure and can generate driving forces in two opposite directions. The friction wheel and the round tube are in a pressing and rolling fit manner, having a maximum output driving force and a stall protection function. The adopted nested structure of adjacent two-level driving modules can increase the maximum moving range of the robot, and at the same time, any number of modules can be freely installed according to the required degrees of freedom. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the overall structure of a concentric tube surgical robot based on a universal friction wheel driving mechanism according to the present invention;

[0023] Figure 2 It is a schematic diagram of the overall structure of a single driving module of a concentric tube surgical robot based on a universal friction wheel driving mechanism according to the present invention;

[0024] Figure 3 It is a schematic diagram of the side structure of a single driving module of a concentric tube surgical robot based on a universal friction wheel driving mechanism according to the present invention;

[0025] Figure 4 It is a schematic diagram of the driving group structure of a single driving module of a concentric tube surgical robot based on a universal friction wheel driving mechanism according to the present invention;

[0026] Figure 5 It is a schematic diagram of the exploded structure of a single driving module of a concentric tube surgical robot based on a universal friction wheel driving mechanism according to the present invention;

[0027] Figure 6 It is a schematic diagram of the movement direction of a concentric tube surgical robot based on a universal friction wheel driving mechanism according to the present invention.

[0028] Reference numerals in the drawings:

[0029] 1. Synchronous pulley set; 2. Bush; 3. Bearing; 4. Universal friction wheel sleeve; 5. Friction wheel; 6. Bearing cover; 7. Round tube; 8. Base; 9. Motor box; 10. Bottom plate; 11. Driving module; 12. First-direction driving group; 13. Second-direction driving group; 14. First fixing member; 15. Second fixing member; 16. Anti-blocking rotation assembly; 17. Servo motor. Detailed implementation manners

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figure 1-6 shown, the present invention provides a concentric tube surgical robot based on a universal friction wheel driving mechanism, including a bottom plate 10 and a plurality of driving modules 11 provided on the bottom plate 10. The overall dimensions of the driving modules 11 decrease or increase sequentially along the length direction of the bottom plate 10, and the driving modules 11 are in a nested structure;

[0032] Among them, the bottom plate 10 is detachably connected to the driving module 11, and the driving modules 11 are sequentially arranged along the length direction of the bottom plate 10. The number of the driving modules 11 is 3, and can be installed according to actual needs. The sizes of adjacent driving modules 11 are not equal. The round tubes 7 in the driving modules 11 are sleeved with the round tubes 7 in adjacent driving modules 11. This structure moves under the action of the transmission device, with a fast movement speed and a light weight, and can improve the installation efficiency and disassembly efficiency during installation through modular design.

[0033] The driving module 11 includes a first-direction driving group 12, a second-direction driving group 13, and a round tube 7 internally sleeved with a concentric tube. The round tube 7 connects the first-direction driving group 12 and the second-direction driving group 13. The first-direction driving group 12 and the second-direction driving group 13 are used for the movement and rotation of the round tube 7;

[0034] When torque is transmitted from the motor of the driving device to the universal friction wheel 5, the friction wheel 5 is in rolling friction fit with the round tube 7 under pressure, so that the movement of the universal friction wheel 5 drives the round tube 7 to move, causing the round tube 7 to rotate and translate. At the same time, since the concentric tube sequentially passes through and connects the round tubes 7 of the driving modules 11, the concentric tube moves and rotates synchronously. The concentric tube is connected to the end effector. Combining with the nested structure, the concentric tube robot can maximize the movement range of the robot during operation.

[0035] The first-direction drive group 12 and the second-direction drive group 13 are both provided with anti-stall components 16. The anti-stall components 16 include universal friction wheel sleeves 4 and a number of friction wheels 5 provided on the universal friction wheel sleeves 4. The universal friction wheel sleeves 4 are of a hollow structure. Moreover, the mounting parts of the universal friction wheel sleeves 4 and the friction wheels 5 are integrally formed, and the friction wheels 5 are fixed to the mounting parts by bolts. The friction wheels 5 are in contact with the round tube 7, and rolling friction cooperation is carried out by pressing the friction wheels 5 against the round tube 7;

[0036] Among them, Figure 6 Figure 5 is an unfolded view of two universal friction wheel sleeves 4. The square in the middle represents the unfolded view of the round tube 7. The arrows on the two sides of the universal friction wheel sleeves 4 indicate the rotational movement of the universal friction wheel sleeves 4, and the round tube 7 cooperates with the universal friction wheel sleeves 4. The friction wheel 5 on the left rotates upward, and its movement is decomposed into V1t (along the tangent direction of the friction wheel 5) and V1a (along the axis direction of the friction wheel 5) on the friction wheel 5. Since the friction wheel 5 can roll freely, that is, the component velocity (V1t) in the tangent direction of the friction wheel 5 will not affect the final movement of the round tube 7, only the component velocity (V1a) in the axis direction can affect the round tube 7. The movement analysis on the right is the same, and finally a final velocity is synthesized on the round tube 7.

[0037] The transmission method of pressing and rolling friction between the friction wheel 5 and the round tube 7 can improve the effect of overload disengagement cooperation, so as to have a stall protection function.

[0038] The first-direction drive group 12 and the second-direction drive group 13 are arranged in opposite directions, and drive devices are connected and provided at the bottoms of the first-direction drive group 12 and the second-direction drive group 13. The first-direction drive group 12 and the second-direction drive group 13 form mutually perpendicular forces on the round tube 7 through the drive devices.

[0039] The drive function of the drive mechanism in this embodiment can be applied to the propulsion and rotation drive devices of a single concentric tube in a concentric tube surgical robot, continuum robots, and all mechanical equipment that requires propulsion and rotation. The drive mechanism has the characteristics of fast translation and rotation speeds, light weight, and stall protection of the friction wheel 5, and at the same time can achieve modular installation.

[0040] Furthermore, the first-direction drive group and the second-direction drive group are respectively arranged at both ends of the round tube 7. The first-direction drive group 12 and the second-direction drive group 13 both include a synchronous pulley group 1, a bushing 2, a bearing 3, a base 8, and a motor box 9. The synchronous pulley group 1 is connected to the universal friction wheel sleeve 4, and the universal friction wheel sleeve 4 is provided with threaded holes for connecting the friction wheels 5;

[0041] Among them, the first-direction driving group 12 and the second-direction driving group 13 are symmetrically arranged before and after on the circular tube 7. The two universal friction wheel sleeves 4 can generate driving forces in two opposite directions. The universal friction wheel sleeve 4 also adopts a hollow design, which can greatly reduce the overall weight. In addition, the hollow structure can cause deformation at the installation part of the friction wheel 5 to a certain extent, thereby generating a pressing force. Compared with the pressing force generated by a spring, the normal pressure provided by this integrated structure is more stable, and it also ensures a more stable pressing fit and driving.

[0042] Due to its integrated structure, when installing the friction wheel 5 on the universal friction wheel sleeve 4, a position for installing threads is reserved at the installation site, making the installation process more convenient.

[0043] The base 8 is fixedly connected to the motor box 9 through bolts. The motor box 9 is used to fix the driving device, which is a servo motor 17. The motor box 9 is fixedly arranged on the bottom plate 10. This driving device can control speed and position accuracy, and can convert voltage signals into torque and rotational speed to drive the controlled object. And this motor is brushless driven, with light weight, large output, fast response, high speed, small inertia, smooth rotation, and stable torque. The control is complex, with a high degree of intelligence, and its electronic commutation method is flexible, which can be square-wave commutation or sine-wave commutation. Its structure is more convenient for maintenance, with high efficiency, low operating temperature, small electromagnetic radiation, long service life, and can be used in various environments.

[0044] Further, the synchronous pulley set 1 is sequentially connected to the bushing 2 and the bearing 3, and the circular tube 7 sequentially passes through the synchronous pulley set 1, the bushing 2, the bearing 3, and the universal friction wheel sleeve 4. The bushing 2 and the bearing 3 are sleeved on one end of the universal friction wheel sleeve 4. There is an active gap between the universal friction wheel sleeve 4 and the circular tube 7. Among them, the torque is transmitted from the synchronous pulley set 1 to the universal friction wheel sleeve 4 through the bushing 2 and the bearing 3, and this structure can generate translational and rotational motions.

[0045] Further, the number of the friction wheels 5 is 4 - 6, and the friction wheels 5 are arranged at equal intervals along the circumference of the circular tube 7. The friction wheels 5 rotate and move along the circumference of the circular tube 7 through the driving device. Four to six friction wheels 5 are annularly installed on the two universal friction wheel sleeves 4 arranged on the circular tube 7, and rolling friction cooperation is carried out by pressing the friction wheels 5 against the circular tube 7. The upper limit of the maximum driving force that this driving mechanism can provide depends on the maximum static friction force between the friction wheel 5 and the circular tube 7. If the circular tube 7 is blocked and the blocking force exceeds the maximum static friction force, relative sliding will occur, and then the torque of the motor will not be transmitted to the circular tube 7 anymore, thereby ensuring safety.

[0046] Furthermore, the driving module 11 further includes a first fixing member 14 and a plurality of second fixing members 15. The first fixing member 14 and the second fixing members 15 are both used to fix the first-direction driving group 12 and the second-direction driving group 13. The first fixing member 14 is disposed between the second fixing members 15, and the second fixing members 15 are symmetrically disposed at both ends of the circular tube 7. The bottoms of the first fixing member 14 and the second fixing members 15 are integrally formed with the base 8. The first fixing member 14 is used to connect the synchronous pulley set 1. The second fixing members 15 are disposed in the middle of the universal friction wheel sleeves 4, and bearings 3 are further provided at the connection between the second fixing members 15 and the universal friction wheel sleeves 4.

[0047] Furthermore, the first fixing member 14 and the second fixing members 15 are both composed of detachable bearing covers 6, and the bearing covers 6 are fixed by bolts. Screw holes are provided on both sides of the bearing cover 6, and the bearing cover 6 is semicircular, and the other half of the bearing cover 6 is fixed on the base 8, which is convenient for structural installation and has strong stability.

[0048] Furthermore, the installation angle between the friction wheel 5 and the central axis of the circular tube 7 is 30 degrees - 60 degrees, and its preferred installation angle is 45 degrees. The friction wheel 5 forms a 45-degree angle with the central axis of the circular tube 7. The two universal friction wheel sleeves 4 on the circular tube 7 generate mutually perpendicular movements on the circular tube 7, thereby driving the circular tube 7. This 45-degree angle is the projection angle of the rotational movement of the friction wheel 5 sleeve decomposed into the translational and rotational movements of the circular tube 7. The larger the angle, the more the movement of the friction wheel 5 sleeve is decomposed into the rotational movement of the circular tube 7. On the contrary, the smaller the angle, the more it is decomposed into the translational movement. And 45 degrees means that the translational movement speed and the rotational movement speed decomposed to the circular tube 7 are equal. When driving the circular tube 7, the required rotational linear speed and translational linear speed are approximately the same.

[0049] Furthermore, the material of the circular tube 7 is rubber. The diameters of the circular tubes 7 disposed on the driving module 11 increase or decrease sequentially along the length direction of the bottom plate 10, and the circular tubes 7 can be sleeved with each other. For modular construction of the robot platform with this driving mechanism, driving mechanisms with different sizes at multiple levels can be used for construction. The size of the driving module 11 and the pipe diameter of the circular tube 7 matched with the module gradually decrease from the upper-level module to the lower-level module. This structure can ensure that in two adjacent modules, the circular tube 7 of the latter level can be wrapped and nested by the circular tube 7 of the former level, thereby increasing the maximum moving distance of a single module in the combined robot.

[0050] Furthermore, it should be noted that the synchronous pulley set 1 includes a set of gear discs and a transmission belt meshed and connected with the gear discs, and one of the gear discs is connected to the shaft of the servo motor 17. Through this structure, the power generated by the motor is transmitted to the universal friction wheel sleeve 4 connected to the synchronous pulley set 1. Since the friction wheel 5 is in pressing and rolling friction fit with the circular tube 7, the movement of the universal friction wheel 5 drives the circular tube 7 to move, and the circular tube 7 generates rotational and translational movements. An end effector is also provided at the end of the concentric tube in the circular tube 7.

[0051] In summary, in this embodiment, the universal friction wheel 5 annularly surrounds the circular tube 7, and the circular tube 7 cooperates with the universal friction wheel sleeve 4. The motor transmits torque to the universal friction wheel 5, and the friction wheel 5 is in pressing and rolling friction fit with the circular tube 7. The movement of the universal friction wheel 5 drives the circular tube 7 to move, causing the circular tube 7 to generate rotational and translational movements. An end effector is connected to the end of the concentric tube on the circular tube 7 and moves synchronously through the drive set on the circular tube 7. When the drive mechanism is in pressing and rolling friction fit with the circular tube 7 through the friction wheel 5, the upper limit of the maximum driving force that the drive mechanism can provide depends on the maximum static friction between the friction wheel 5 and the circular tube 7. If the circular tube 7 is blocked, and the blocking force exceeds the maximum static friction, relative sliding will occur, and then the torque of the motor will not continue to be transmitted to the circular tube 7, having an anti-blocking effect. Moreover, this implementation is built by using three drive modules 11 with different sizes, and any number of modules can be freely installed according to the required degrees of freedom.

[0052] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

Claims

1. A concentric tube surgical robot based on a universal friction wheel drive mechanism, characterized in that: it includes a bottom plate (10) and a number of drive modules (11) provided on the bottom plate (10). The overall dimensions of the drive modules (11) decrease or increase sequentially along the length direction of the bottom plate (10), and the drive modules (11) are in a nested structure; the drive module (11) includes a first-direction drive group (12), a second-direction drive group (13), and a circular tube (7) with a concentric tube sleeved inside. The circular tube (7) is connected to the first-direction drive group (12) and the second-direction drive group (13), and the first-direction drive group (12) and the second-direction drive group (13) are used for the movement and rotation of the circular tube (7); anti-blocking rotation components (16) are provided on both the first-direction drive group (12) and the second-direction drive group (13). The anti-blocking rotation components (16) include a universal friction wheel sleeve (4) and a number of friction wheels (5) provided on the universal friction wheel sleeve (4). The universal friction wheel sleeve (4) is a hollow structure. The friction wheels (5) are in contact with the circular tube (7), and the friction wheels (5) are pressed against the circular tube (7) for rolling friction cooperation; the first-direction drive group (12) and the second-direction drive group (13) are arranged in opposite directions, and drive devices are connected to the bottoms of both the first-direction drive group (12) and the second-direction drive group (13). The first-direction drive group (12) and the second-direction drive group (13) form mutually perpendicular forces on the circular tube (7) through the drive devices; the first-direction drive group and the second-direction drive group are respectively provided at both ends of the circular tube (7). The first-direction drive group (12) and the second-direction drive group (13) both include a synchronous pulley group (1), a bushing (2), a bearing (3), a base (8), and a motor box (9). The synchronous pulley group (1) is connected to the universal friction wheel sleeve (4), and the universal friction wheel sleeve (4) is provided with threaded holes for connecting the friction wheels (5); the base (8) is fixedly connected to the motor box (9) by bolts. The motor box (9) is used to fix the drive device, and the drive device is a servo motor (17). The motor box (9) is fixedly provided on the bottom plate (10); the number of the friction wheels (5) is 4 - 6, and the friction wheels (5) are arranged at equal intervals along the circumference of the circular tube (7). The friction wheels (5) rotate and move along the circumference of the circular tube (7) through the drive device; the installation angle between the friction wheel (5) and the central axis of the circular tube (7) is 30 degrees - 60 degrees.

2. The concentric tube surgical robot based on a universal friction wheel drive mechanism according to claim 1, characterized in that: the synchronous pulley group (1) is sequentially connected to the bushing (2) and the bearing (3), and the circular tube (7) sequentially passes through the synchronous pulley group (1), the bushing (2), the bearing (3), and the universal friction wheel sleeve (4).

3. The concentric tube surgical robot based on a universal friction wheel drive mechanism according to claim 1, characterized in that: The driving module (11) further includes a first fixing member (14) and a plurality of second fixing members (15). The first fixing member (14) and the second fixing members (15) are both used to fix the first-direction driving group (12) and the second-direction driving group (13). The first fixing member (14) is disposed between the second fixing members (15), and the second fixing members (15) are symmetrically disposed at both ends of the circular tube (7).

4. A concentric tube surgical robot based on a universal friction wheel driving mechanism according to claim 3, wherein: both the first fixing member (14) and the second fixing members (15) are composed of detachable bearing covers (6), and the bearing covers (6) are fixed by bolts.

5. A concentric tube surgical robot based on a universal friction wheel driving mechanism according to claim 1, wherein: the circular tube (7) is made of rubber, and the diameters of the circular tubes (7) disposed on the driving module (11) increase or decrease sequentially along the length direction of the bottom plate (10), and the circular tubes (7) can be sleeved with each other.

6. A concentric tube surgical robot based on a universal friction wheel driving mechanism according to claim 1, wherein: the synchronous pulley group (1) includes a set of gear discs and a transmission belt meshed with the gear discs, and one of the gear discs is connected to the shaft of the servo motor (17).

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