Proximal drive structure of a flexible arm

Abstract

The present invention discloses a proximal drive structure of a flexible arm, which includes a drive assembly for driving the distal execution structure of the flexible arm to perform a bending motion. The drive assembly includes a drive mechanism, a drive rope that reciprocates by being driven by the drive mechanism, and two traction wires fixedly connected to the drive rope respectively. The traction wires are cooperatively connected with a certain degree of freedom of the distal execution structure to realize the motion of this degree of freedom under the drive of the drive rope. The structure of the present invention is simple, with a lighter overall weight, easier to process, lower cost, and more compact size. Compared with the fixed and power connection of the lead screw, the structural complexity is also significantly reduced. At the same time, the degree of freedom of the end of the flexible arm can be conveniently increased by increasing the number of this transmission chain, and the solution is easier to implement and promote.

Description

Technical Field

[0001] The present invention relates to the technical field of surgical robots, and particularly to a proximal drive structure of a flexible arm. Background Art

[0002] The development and progress of technology have promoted the enrichment and improvement of surgical robot technology, and also made surgical robot technology more and more mature and widely used. The development and application of surgical robots not only reduce the physical labor of doctors during surgery, but also make the patient's wound smaller, less bleeding, lower risk of postoperative infection, and faster recovery during surgery. For surgical robots, people not only require that surgical robots can use multiple robotic arms and multiple surgical openings to complete corresponding surgeries, but also hope that surgical robots have fewer surgical openings, higher degrees of freedom of instruments, more reachable positions, and larger movement spaces, etc. For these requirements, flexible arms can better meet them. Flexible arms not only have a high degree of freedom, but also because the arm body is flexible, when the flexible arm enters the human body, it can adjust its posture according to the space of internal organs. In this way, the end of the instrument can bypass tissues without causing harm to the tissues, and at the same time can reach the patient's lesion to complete the surgical operation.

[0003] At present, there are some defects in the distal implementation structure of flexible arms. For example, parts are connected by hinges, which makes the installation of the transmission structure difficult. The disk-stack type distal execution structure can not only meet the mechanical requirements of the surgical scenario, but also makes the overall installation convenient and the processing easier to achieve. In the proximal drive structure, a lead screw-nut form is used to drive the nitinol wire to move linearly. The overall size and weight of this structure are relatively large, and the cost is high, which is not conducive to the application and popularization of flexible arm technology. Summary of the Invention

[0004] Object of the Invention: Aiming at the above deficiencies, the present invention proposes a proximal drive structure of a flexible arm, which uses the principle of tungsten wire rope drive and guidance to realize the linear movement of the nitinol wire, not only streamlining the overall structure, but also greatly reducing the weight of the transmission structure, reducing the external dimensions, and significantly reducing the cost of the instrument, which is more conducive to the application and popularization of flexible arm instruments.

[0005] Technical Solution:

[0006] A proximal drive structure of a flexible arm includes: a drive assembly for driving the distal execution structure of the flexible arm to bend, the drive assembly including a drive mechanism, a drive rope that reciprocates by driving of the drive mechanism, and two traction wires respectively fixedly connected to the drive rope, and the traction wires are cooperatively connected with a certain degree of freedom of the distal execution structure to realize the movement of this degree of freedom driven by the drive rope.

[0007] The number of the drive assemblies is set according to the degrees of freedom of the bending movement of the distal execution structure.

[0008] The driving assembly is further provided with a transmission member respectively connecting the driving rope and the traction wire, which drives the traction wire to move under the reciprocating motion of the driving rope.

[0009] Guide wheels are rotatably installed on both sides of the transmission member, and the driving rope is wound around the guide wheels at both ends thereof to change the extension direction of the driving rope. The transmission member is slidably installed in a chute provided on the carrier, and the guide wheels are provided at both ends of the chute.

[0010] The direction of the chute is perpendicular to the plane where the carrier is located.

[0011] A rope groove for threading the driving rope and a wire groove for threading the traction wire are formed in the transmission member along its sliding direction; a pin shaft for fixing the driving rope and the traction wire is also threaded between the rope groove and the wire groove on the transmission member.

[0012] The driving mechanism includes a driving motor and a transmission winch connected to the motor shaft of the driving motor, and both ends of the driving rope are wound around the transmission winch after being connected and matched with the traction wire.

[0013] Two wire grooves with opposite directions are provided on the transmission winch, and both ends of the driving rope are respectively fixed and wound around the two wire grooves of the transmission winch.

[0014] The driving assembly is installed on the carrier, and a tensioning member for adjusting the tension of the driving rope is also installed on the carrier.

[0015] The tensioning member includes a tensioning bracket installed on the carrier through an elastic member, and a tensioning wheel is rotatably installed on the tensioning bracket, and the driving rope is wound around the tensioning wheel.

[0016] The driving rope is made of tungsten wire rope, and the traction wire is made of nitinol alloy wire.

[0017] Beneficial effects:

[0018] 1. The structure of the present invention is simple, the overall weight is lighter, it is easier to process, the cost is lower, the size is more compact, and compared with the fixation and power connection of the lead screw, the structural complexity is also significantly reduced. At the same time, the degree of freedom of the end of the flexible arm can be conveniently increased by increasing the number of the transmission chains, and the scheme is easier to implement and promote.

[0019] 2. The present invention can reduce the distance between the driving rope and the alloy wire by fixing to the transmission member with a locking pin shaft, thereby reducing the overturning moment generated by the force on the alloy wire on the driving rope, and also reducing the friction between the transmission member and the chute.

[0020] 3. The present invention also adds a tensioning structure, which is beneficial to the tensioning of the drive rope and extends the service life of the instrument. The elastic force of the tensioning structure is provided by a disc spring, reducing the axial dimension of the tensioning wheel structure, making the structure more compact and small, and thus reducing the overall size of the instrument seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the flexible arm of the present invention;

[0022] Figure 2 is a schematic diagram of the distal execution structure;

[0023] Figure 3 is a schematic structural diagram of the end of the distal execution structure;

[0024] Figure 4 is a schematic structural diagram of the proximal drive structure of the flexible arm of the present invention;

[0025] Figure 5 is a schematic diagram of the drive assembly;

[0026] Figure 6 is a schematic structural diagram of the transmission winch;

[0027] Figure 7 is a sectional view of the drive assembly;

[0028] Figure 8 is a schematic structural diagram of the transmission member;

[0029] Figure 9 is a schematic diagram of the tensioning structure;

[0030] Figure 10 is a schematic working diagram of the flexible arm of the present invention.

[0031] In the figure, 1 - proximal drive structure, 2 - distal execution structure;

[0032] 11 - carrier, 12 - drive assembly, 13 - fixed disk, 14 - column, 15 - guide tube;

[0033] 111 - bearing plate, 112 - fixed block;

[0034] 1121 - wheel groove, 1122 - chute;

[0035] 121 - drive motor, 122 - transmission winch, 123 - guide pulley group, 124 - drive rope, 125 - transmission member, 126 - follower alloy wire, 127 - tensioning member;

[0036] 1221 - upper winding groove, 1222 - lower winding groove;

[0037] 1231 - First guide wheel, 1232 - Second guide wheel, 1233 - Third guide wheel, 1234 - Fourth guide wheel;

[0038] 1251 - Rope groove, 1252 - Wire groove, 1253 - Locking pin shaft;

[0039] 1271 - Disc spring, 1272 - Tensioning bracket, 1273 - Tensioning wheel;

[0040] 21 - Passing section, 22 - Bending section, 23 - Locking disc;

[0041] 211 - Wire passing disc, 221 - Skeleton tube, 222 - Skeleton disc. Detailed implementation mode

[0042] The present invention will be further illustrated below in conjunction with the accompanying drawings and specific embodiments.

[0043] Figure 1 It is a structural schematic diagram of the flexible arm of the present invention. As Figure 1 shown, the flexible arm of the present invention includes a proximal drive structure 1 and a distal execution structure 2. Referring to Figure 2 , the proximal drive structure 1 of the flexible arm of the present invention includes a carrier 11, a drive assembly 12 arranged on the carrier 11, a fixed disc 13 fixedly connected to the end of the distal execution structure 2, a column 14 for connecting the carrier 11 and the fixed disc 13, and a guide tube 15 arranged between the carrier 11 and the fixed disc 13 for passing the alloy wire used for transmission in the drive assembly 12.

[0044] As Figure 1 , 2 shown, the distal execution structure 2 includes a passing section 21, a bending section 22 and a locking disc 23. The passing section 21 is formed by the cooperative installation of a plurality of wire passing discs 211. The wire passing disc 211 is an annular disc, and a plurality of groups of wire passing holes are arranged at intervals in the vertical direction thereon, thereby forming a channel for the alloy wire to pass through. The number of groups of wire passing holes is related to the attitude adjustment freedom degree of the flexible arm, that is, the same as the number of drive assemblies 12 of the proximal drive structure 1. For example, if the freedom degree adjustment of the flexible arm is two freedom degrees of yaw and pitch, then the number of groups of wire passing holes is two groups, and each group of wire passing holes is oppositely arranged in the circumferential direction of the wire passing disc. As Figure 3 shown, the bending section 22 includes a skeleton tube 221 that can achieve yaw or pitch arranged therein and a plurality of skeleton discs 222 sleeved on the outside of the skeleton tube 221 along its length direction. The skeleton tube 221 is a hollow structure, and the skeleton tube 221 is flexible and bendable; the skeleton discs 222 are fixedly sleeved on the outside of the skeleton tube 221, and a plurality of groups of wire passing holes are arranged at intervals in the vertical direction thereon. The arrangement of the wire passing holes is the same as that on the wire passing disc 211, thereby forming a channel for the alloy wire to pass through. As Figure 3As shown, a plurality of groups of wire fixing holes are spaced apart in the vertical direction on the locking disc 23, and the number of wire fixing holes is set to be the same as that of the wire passing holes on the wire passing disc 211 and the skeleton disc 222. The alloy wire passes through the guiding tube 15 and then successively passes through the wire passing holes opened on a plurality of wire passing discs 211 in the passing segment 21, the wire passing holes opened on a plurality of skeleton discs 222 in the bending segment 22, and is finally fixed in the wire fixing holes on the locking disc 23.

[0045] As Figure 4 shown, the carrier 11 includes a carrier plate 111 connected to the fixed disc 13 through the cooperation of the columns 14 and a plurality of fixing blocks 112 installed on the carrier plate 111. The fixing blocks 112 are arranged in pairs, and the number of pairs of the fixing blocks 112 corresponds to the driving assembly 12. Taking the vertical direction shown in the figure as the up-down direction, wheel grooves 1121 for rotatably installing guide wheels are respectively opened at the upper and lower ends of the fixing blocks 112, and a sliding groove 1122 in the up-down direction is opened on the fixing blocks 112, as Figure 7 shown.

[0046] Referring Figure 4 、 5 , the driving assembly 12 includes a driving motor 121, a transmission winch 122, a guide wheel group 123, a transmission member 125, a driving rope 124 and a following alloy wire 126. The driving motor 121 is fixedly installed below the carrier plate 111; the transmission winch 122 is arranged above the carrier plate 111 and is installed in cooperation with the motor shaft of the driving motor 121. It forms a triangular arrangement with the fixing blocks 112 arranged in pairs on the carrier plate 111, and guide wheels are rotatably installed in the wheel grooves 1121 at the upper and lower ends of the two fixing blocks 112. The guide wheels installed at the upper and lower ends of one fixing block 112 are respectively the first guide wheel 1231 and the second guide wheel 1232, and the guide wheels installed at the lower and upper ends of the other fixing block 112 are respectively the third guide wheel 1233 and the fourth guide wheel 1234, thus forming the guide wheel group 123; two wire winding grooves with opposite directions are arranged on the transmission winch 122, namely an upper wire winding groove 1221 and a lower wire winding groove 1222, as Figure 6 shown; one end of the driving rope 124 is fixed and wound on the upper wire winding groove 1221 of the transmission winch 122, and successively winds around the first guide wheel 1231, passes through the fixing block 112, winds around the second guide wheel 1232, winds around the third guide wheel 1233, passes through the other fixing block 112, winds around the fourth guide wheel 1234, and finally winds and is fixed on the lower wire winding groove 1222 of the transmission winch 122, as Figure 5As shown in the figure. The transmission member 125 is slidably disposed in the chute 1122 inside the fixed block 112. The driving rope 124 passing through the fixed block 112 is connected to the transmission member 125 without relative sliding fit. The upper end of the follower alloy wire 126 is fixedly connected to the transmission member 125. Its lower end sequentially passes through the guiding tube 15, the wire passing disc 211 and the framework disc 222, and is finally fixed on the locking disc 23. By driving the driving winch 122 to rotate through the driving motor 121, the movement of the driving rope 124 on its winding path can be driven, so that the relative sliding of the transmission members 125 in the two fixed blocks 112 in the vertical direction can be driven. Furthermore, the follower of the corresponding follower alloy wire 126 can be driven through the transmission member 125, so that the attitude adjustment action of the distal execution structure 2 can be realized through the two follower alloy wires 126.

[0047] In the present invention, the number of the driving assemblies 12 is consistent with the degrees of freedom of the attitude adjustment of the flexible arm. In this embodiment, the yaw or pitch movement of the flexible arm is taken as an example for illustration.

[0048] Furthermore, as Figure 8 shown in the figure, the shape of the transmission member 125 is consistent with the chute 1122 opened on the fixed block 112. A rope groove 1251 for passing through the driving rope 124 and a wire groove 1252 for passing through the follower alloy wire 126 are opened thereon in the vertical direction. At the same time, a pin shaft groove perpendicular to the directions of the rope groove 1251 and the wire groove 1252 is also opened on the transmission member 125 between the rope groove 1251 and the wire groove 1252. The pin shaft groove communicates with both the rope groove 1251 and the wire groove 1252. Through such a design, after the driving rope 124 and the follower alloy wire 126 are respectively passed through the rope groove 1251 and the wire groove 1252 of the transmission member 125, by passing a locking pin shaft 1253 through the pin shaft groove, the fixed connection between the driving rope 124 and the follower alloy wire 126 and the transmission member 125 can be realized through the frictional force between the locking pin shaft 1253 and the driving rope 124 and the follower alloy wire 126, that is, a non-relative sliding connection.

[0049] Furthermore, when the locking pin shaft 1253 is passed through the pin shaft groove, the two sides of it in contact with the driving rope 124 and the follower alloy wire 126 are respectively embedded into the rope groove 1251 and the wire groove 1252, so that the driving rope 124 and the follower alloy wire 126 can be further pressed, thereby increasing the frictional force between it and the two.

[0050] In the present invention, a single locking pin shaft 1253 can simultaneously press the follower alloy wire 126 and the driving rope 124, effectively reducing the radial dimension of the transmission member 125, and also making the structural design smaller and more compact. However, the present invention is not limited to this. The present invention can directly fix the follower alloy wire 126 and the driving rope 124 on the transmission member 125; or two locking pin shafts can be used to respectively press the follower alloy wire 126 and the driving rope 124 to realize detachable installation.

[0051] In the present invention, the driving rope 124 is made of tungsten wire rope, and the follow-up alloy wire 126 is made of nickel-titanium alloy wire. However, in the present invention, the material of the follow-up alloy wire 126 includes but is not limited to nickel-titanium alloy wire, and any material with certain rigidity and capable of bending can be used. Similarly, the material of the driving rope 124 also includes but is not limited to tungsten wire rope, and any flexible material that can be bent, wear-resistant, and tensile can be used.

[0052] Furthermore, due to the fact that the nickel-titanium alloy wire has relatively large stiffness and hardness, and the tungsten wire rope is relatively soft, the pin shaft groove in the present invention is asymmetrically arranged relative to the rope groove 1251 and the wire groove 1252, and it is more biased towards the rope groove 1251. Thus, when the locking pin shaft 1253 is inserted into the pin shaft groove, the locking pin shaft 1253 can press the tungsten wire rope more, and at the same time can also press the nickel-titanium alloy wire.

[0053] Refer to Figure 4 、 9 As shown in, the driving assembly 12 of the present invention further includes a tensioning member 127. The tensioning member 127 is fixedly installed on the driving rope 124 passing route between the guide wheels at the lower ends of the two fixing blocks 112 on the bearing plate 111. It includes a tensioning bracket 1272 vertically installed on the bearing plate 111 through a disc spring 1271, and a tensioning wheel 1273 rotatably installed on the tensioning bracket 1272. The driving rope 124 passes around the tensioning wheel 1273 after passing through the second guide wheel 1232 and then winds around the third guide wheel 1233. The present invention realizes the cooperation between the tensioning wheel 1273 and the driving rope 124 through the elasticity of the disc spring 1271, so as to adjust the tension of the driving rope 124 adaptively. Using the disc spring 1271 is more conducive to saving structural space. In the present invention, for the entire transmission chain, the tensioning member 127 is not necessary. For consumables, if the service life requirement is not high, the tensioning member 127 can be not used.

[0054] Figure 10 As shown in the working schematic diagram of the flexible arm of the present invention, taking the transmission of a set of driving assemblies 12 as an example, when the driving motor 121 rotates in a certain direction, the transmission winch 122 rotates along with the driving motor 121 in this direction. The rotation of the transmission winch structure 122 drives the driving rope 124 to move under the guidance of the guide wheel group 123. Since the transmission member 125 is fixedly connected to the driving rope 124 and the follow-up alloy wire 126, the driving rope 124 drives the transmission member 125 to move up and down in the sliding groove 1122. In this way, the transmission member 125 in one fixing block 112 will pull the follow-up alloy wire 126, and the transmission member 125 in the other fixing block 112 will push the follow-up alloy wire 126. The ends of the two follow-up alloy wires 126 both pass through the passing section 21 and the bending section 22 and are fixedly connected to the locking disc 23. Thus, by the one-way pulling and releasing of the two follow-up alloy wires 126, the locking disc 23 can be driven to move from position A to position B, thereby realizing the adjustment of the end pose of the instrument.

[0055] The present invention only details the swing of one degree of freedom at the end of the flexible arm. More degrees of freedom at the end of the flexible arm can be achieved by increasing the number of drive motors 121, the corresponding number of transmission chains, and the number of series-connected flexible arms.

[0056] The present invention adopts a transmission scheme with a tungsten wire rope. The structural components mainly include a tungsten wire rope, a guide wheel, a winch, and a slider. These parts are all small and light. Compared with the common linear motion scheme such as ball screw transmission, the overall weight of this scheme is lighter, it is easier to process, the cost is lower, and the size is more compact. Compared with the fixation and power connection of the ball screw, the structural complexity is also significantly reduced. At the same time, the degrees of freedom at the end of the flexible arm can be conveniently increased by increasing the number of such transmission chains, and the scheme is easier to implement and promote; the nickel-titanium alloy wire is fixedly connected to the locking disc and thus is a load-bearing member. Fixing the tungsten wire rope and the nickel-titanium alloy wire to the slider through a locking pin shaft can reduce the distance between the tungsten wire rope and the nickel-titanium alloy wire, thereby reducing the overturning moment generated by the force on the nickel-titanium alloy wire on the tungsten wire rope and also reducing the friction between the slider and the guide chute; in addition, the present invention also adds a tensioning structure for the tungsten wire rope, which is beneficial to the tensioning of the tungsten wire rope and extends the service life of the instrument. The elastic force of the tensioning wheel structure is provided by a disc spring, which reduces the axial dimension of the tensioning wheel structure, makes the structure of this scheme more compact and small, and thus reduces the overall size of the instrument seat.

[0057] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations (such as quantity, shape, position, etc.) can be made to the technical solution of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A proximal drive structure for a flexible arm, characterized in that: It includes a driving component for driving the bending movement of the distal execution structure of the flexible arm. The driving component includes a driving mechanism, a driving rope that reciprocates through the driving of the driving mechanism, and two traction wires fixedly connected to the driving rope respectively. The traction wire is connected and matched with a certain degree of freedom of the distal execution structure to realize the movement of this degree of freedom under the drive of the driving rope. The driving component is installed on a carrier, and is provided with a transmission member connecting the driving rope and the traction wire respectively, driving the traction wire to move under the reciprocating movement of the driving rope. The transmission member is slidably installed in a chute provided on the carrier. Guide wheels are rotatably installed on both sides of the transmission member. The driving rope is wound around the guide wheels at both ends thereof to change the extension direction of the driving rope. The guide wheels are arranged at both ends of the chute. A rope groove for threading the driving rope and a wire groove for threading the traction wire are formed on the transmission member along its sliding direction. A pin shaft groove perpendicular to the directions of the rope groove and the wire groove is also formed on the transmission member between the rope groove and the wire groove. The pin shaft groove communicates with both the rope groove and the wire groove. The driving rope and the traction wire are fixedly connected to the transmission member through the frictional force between the locking pin shaft and the driving rope and the traction wire in the pin shaft groove.

2. The proximal drive structure of the flexible arm according to claim 1, characterized in that: The number of the driving components is set according to the degrees of freedom of the bending movement of the distal execution structure.

3. The proximal drive structure of the flexible arm according to claim 1, characterized in that: The direction of the chute is perpendicular to the plane where the carrier is located.

4. The proximal drive structure of the flexible arm according to claim 1, characterized in that: The driving mechanism includes a driving motor and a transmission winch connected to the motor shaft of the driving motor. The two ends of the driving rope are connected and matched with the traction wire and then wound around the transmission winch.

5. The proximal drive structure of the flexible arm according to claim 4, characterized in that: Two winding grooves with opposite directions are provided on the transmission winch. The two ends of the driving rope are respectively fixed and wound around the two winding grooves of the transmission winch.

6. The proximal drive structure of the flexible arm according to claim 1, characterized in that: A tensioning member for adjusting the tension of the driving rope is also installed on the carrier.

7. The proximal drive structure of the flexible arm according to claim 6, characterized in that: The tensioning member includes a tensioning bracket installed on the carrier through an elastic member. A tensioning wheel is also rotatably installed on the tensioning bracket. The driving rope is wound around the tensioning wheel.

8. The proximal drive structure of the flexible arm according to any one of claims 1 to 7, characterized in that: The driving rope is made of tungsten wire rope, and the traction wire is made of nitinol wire.

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