A high-precision rigid-flexible coupling surgical robot for narrow natural cavities

Abstract

The application discloses a kind of high-precision rigid-flexible coupling surgical robot for narrow natural cavity, including rigid-flexible coupling arm, rigid tubular rod and rope drive mechanism;The diameter of the rigid-flexible coupling arm is 2-3mm, and the rigid-flexible coupling arm includes rigid arm section and flexible arm section;The rigid arm section is connected between rigid tubular rod and flexible arm section, and gear rotating joint for rope drive control rotation is arranged between the two ends of rigid arm section;The end of the flexible arm section is provided with end effector, and multiple rope drive rotating joints are sequentially separated and arranged between the two ends of flexible arm section along its arm length track, and the rotation axes of adjacent rope drive rotating joints are perpendicular to each other;The end of the rigid tubular rod away from rigid-flexible coupling arm is connected with rope drive mechanism;Multiple drive ropes of the rope drive mechanism pass through rigid tubular rod and are respectively connected with gear rotating joint and multiple rope drive rotating joints for rope drive connection;After adopting this scheme, the effect of small volume, flexible and rigid requirements of mechanical arm can be considered.

Description

Technical Field

[0001] This invention relates to the field of robotics, and in particular to a high-precision rigid-flexible coupling surgical robot for narrow natural cavities. Background Technology

[0002] With the continuous development of technology, the demand for precise operation in environments with complex curvature changes is increasing in the field of small-cavity surgery. In order to meet the flexibility required for small-cavity surgery and at the same time to miniaturize the end effector, flexible surgical robots have emerged.

[0003] Existing flexible robotic arms are typically integrated with their drive systems and mounting platforms to form a surgical robot system. This system generally suffers from low system integration, spatial redundancy, and low end-effector control precision. For example, patent CN119564350A, titled "Wire Drive Device and Surgical Robot," provides a wire drive device capable of compensating for horizontal displacement of the wire, ensuring the stability of subsequent surgical instrument control. However, this drive device suffers from low system integration and slow transmission control response. Furthermore, because its overall structural space has not been effectively miniaturized, its practicality for small-cavity surgeries is limited.

[0004] For example, most commonly seen flexible rope-driven robotic arms consist of joints composed of a single flexible structure connected in series. For instance, patent number CN115252138A, titled "An Oral and Throat Surgical Robot," proposes a design that uses snake-bone flexible joints and actuator slide rail assemblies to simultaneously meet the linear and bending requirements of the flexible arm segment. However, due to its all-snake-bone joint design, this flexible robotic arm suffers from limited bending range and low response during operation, resulting in somewhat limited overall motion performance.

[0005] Therefore, developing a surgical robot that is small in size and can meet the requirements of both flexibility and rigidity of robotic arms has become an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a high-precision rigid-flexible coupling surgical robot for narrow natural cavities, so as to achieve the effect of small size and meeting the requirements of both flexibility and rigidity of the robotic arm.

[0007] To address the aforementioned technical problems, this invention provides a high-precision rigid-flexible coupling surgical robot for narrow natural cavities, comprising a rigid-flexible coupling arm, a rigid tubular rod, and a cable-driven mechanism. The rigid-flexible coupling arm has a diameter of 2-3 mm and includes a rigid arm segment and a flexible arm segment. One end of the rigid arm segment is connected to one end of the rigid tubular rod, and the other end of the rigid arm segment is connected to the flexible arm segment. A cable-driven gear joint for controlled rotation is provided between the two ends of the rigid arm segment. An end effector is installed at the end of the flexible arm segment away from the rigid arm segment, and multiple cable-driven rotation joints are arranged sequentially along the arm length trajectory between the two ends of the flexible arm segment, with the rotation axes of adjacent cable-driven rotation joints perpendicular to each other. The end of the rigid tubular rod away from the rigid-flexible coupling arm is connected to the cable-driven mechanism. Multiple drive cables of the cable-driven mechanism pass through the rigid tubular rod and are respectively connected to the gear joint and the multiple cable-driven rotation joints.

[0008] In one embodiment, the rope drive mechanism includes a frame and a plurality of rope drive units disposed on the frame, wherein the plurality of rope drive units are respectively used to control the extension and retraction states of the plurality of drive ropes.

[0009] In one embodiment, the rigid arm segment includes a rigid first arm segment and a rigid second arm segment. One end of the rigid first arm segment is connected to the rigid tubular rod, and the other end of the rigid first arm segment is rotatably connected to one end of the rigid second arm segment via the gear rotary joint. The other end of the rigid second arm segment is connected to the flexible arm segment. The flexible arm segment includes a plurality of snake-bone joints arranged sequentially along its arm length trajectory. Adjacent snake-bone joints are rotatably connected via the rope-driven rotary joint. The drive rope passes sequentially through the rigid tubular rod, the rigid first arm segment, the gear rotary joint, the rigid second arm segment, and the plurality of snake-bone joints, such that a portion of the drive rope is connected to the end effector rope drive, while the remaining drive rope is connected to the end effector rope drive of the flexible arm segment.

[0010] In one embodiment, the gear rotation joint includes a first gear plate, a second gear plate, a connecting rod, and a guide rope component; two first gear plates are disposed on opposite sides of the end of the rigid first arm segment; two second gear plates are disposed on opposite sides of the end of the rigid second arm segment, and the two second gear plates mesh with the two first gear plates respectively. The changing meshing position of the two second gear plates with the two first gear plates is used to realize the rotation of the gear rotation joint; one end of the two connecting rods is rotatably connected to the gear axial center of the two first gear plates respectively, and the other end of the two connecting rods is rotatably connected to the gear axial center of the two second gear plates respectively; the guide rope component is connected to the two connecting rods; the drive rope passes through the rigid first arm segment, passes through the guide rope component, and then passes through the rigid second arm segment.

[0011] In one embodiment, the rigid-flexible coupling arm is provided with actuator rope passage channels and arm segment rope passage channels; the actuator rope passage channels and the arm segment rope passage channels pass sequentially through the rigid first arm segment, the rope guide component, the rigid second arm segment, and multiple snake-bone joints; a portion of the drive ropes pass through multiple actuator rope passage channels and are connected to the end effector rope drive; the remaining drive ropes pass through multiple arm segment rope passage channels and are connected to the end effector rope drive of the flexible arm segment.

[0012] In one embodiment, the end effector includes two rotatably connected jaws; one end of a drive rope passes through one actuator rope passage, then around the rotatable connection of one jaw, and passes through the other actuator rope passage, such that both ends of this drive rope are respectively connected to two rope drive units, and this drive rope is fixedly connected to the rotatable connection of this jaw; one end of the other drive rope passes through one actuator rope passage, then around the rotatable connection of another jaw, and passes through the other actuator rope passage, such that both ends of this drive rope are respectively connected to two other rope drive units, and this drive rope is fixedly connected to the rotatable connection of this jaw.

[0013] In one embodiment, the actuator rope passage is located near the outer side of the rigid-flexible coupling arm; the arm segment rope passage is located near the middle of the rigid-flexible coupling arm.

[0014] In one embodiment, the rigid-flexible coupling arm is provided with a weight-reduction channel that passes sequentially through the rigid first arm segment, the guide rope component, the rigid second arm segment, and multiple snake-bone joints.

[0015] In one embodiment, the rope drive unit includes a drive motor, a lead screw, a ball bearing housing with a threaded hole, a guide rod, a guide wheel, and the drive rope; the drive motor is used to drive the lead screw to rotate; the lead screw is threadedly connected to the ball bearing housing; the drive rope is connected to the ball bearing housing; the guide rod is arranged parallel to the lead screw and passes through the ball bearing portion of the ball bearing housing; the drive rope passes around the guide wheel and is connected to the rigid-flexible coupling arm rope drive.

[0016] The beneficial effects of this invention are as follows:

[0017] First, by improving the overall system integration and adopting an ultra-fine diameter, millimeter-level motion precision design, this solution not only gives the surgical robot a flexible working range but also enhances its overall convenience, making it easy to install on most existing robotic arm platforms on the market, thereby meeting diverse work needs.

[0018] Furthermore, this solution utilizes a rigid and flexible arm segment to form a rigid-flexible coupling arm. This approach is a rigid-flexible coupling design that combines a rigid pure rolling joint with a flexible joint in series, which can solve the problem of limited movement of traditional robotic arms in narrow and convoluted cavities. The rigid pure rolling joint ensures high responsiveness, while the series of flexible joint segments provides a flexible working angle range. Simultaneously, this design enhances the rigidity and integration capabilities of the rigid-flexible coupling arm, providing a solution to the complex application challenges in small-cavity surgeries. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure provided in an embodiment of the present invention;

[0021] Figure 2 yes Figure 1 A schematic diagram of a rigid-flexible coupling arm structure;

[0022] Figure 3 yes Figure 2 A schematic diagram of the rigid arm segment structure;

[0023] Figure 4 yes Figure 2 A schematic diagram of the flexible arm segment structure;

[0024] Figure 5 yes Figure 2A schematic diagram of the end effector structure;

[0025] Figure 6 yes Figure 1 A schematic diagram of the rope-driven mechanism.

[0026] The attached figures are labeled as follows:

[0027] 100. Rigid-flexible coupling arm; 110. Rigid arm segment; 111. Rigid first arm segment; 112. Rigid second arm segment; 120. Flexible arm segment; 121. Rope-driven rotary joint; 122. Snake-bone joint; 130. Gear rotary joint; 131. First gear plate; 132. Second gear plate; 133. Connecting rod; 134. Rope guide component; 141. Actuator rope passage; 142. Arm segment rope passage; 143. Weight reduction channel;

[0028] 200. Rigid tubular rod;

[0029] 300. Rope drive mechanism; 310. Drive rope; 320. Frame; 330. Rope drive unit; 331. Drive motor; 332. Transmission screw; 333. Ball bearing seat; 334. Guide rod; 335. Guide wheel;

[0030] 400. End effector; 410. Gripper; 420. Rotary connection part. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0032] This invention provides a high-precision rigid-flexible coupling surgical robot for narrow natural cavities, such as... Figure 1 and Figure 2 As shown, the device includes a rigid-flexible coupling arm 100, a rigid tubular rod 200, and a rope-driven mechanism 300. The diameter of the rigid-flexible coupling arm 100 is 2-3 mm, and it includes a rigid arm segment 110 and a flexible arm segment 120. One end of the rigid arm segment 110 is connected to one end of the rigid tubular rod 200, and the other end of the rigid arm segment 110 is connected to the flexible arm segment 120. A gear joint 130 for rope-driven rotation control is provided between the two ends of the rigid arm segment 110. The flexible arm segment 120 is located away from the rigid arm. An end effector 400 is installed at the end of segment 110, and multiple rope-driven rotary joints 121 are arranged sequentially along the arm length trajectory between the two ends of the flexible arm segment 120, with the rotation axes of adjacent rope-driven rotary joints 121 being perpendicular to each other; the end of the rigid tubular rod 200 away from the rigid-flexible coupling arm 100 is connected to the rope drive mechanism 300; multiple drive ropes of the rope drive mechanism 300 pass through the rigid tubular rod 200 and are respectively connected to the gear rotary joint 130 and the multiple rope-driven rotary joints 121.

[0033] When applied, the rigid-flexible coupling arm 100 has a diameter of 2-3mm, making its size very small, thus meeting the usage requirements in various narrow scenarios. When it is necessary to control the rigid-flexible coupling arm 100 to perform operations, the control gear rotation joint 130 of the rope drive mechanism 300 and multiple rope drive rotation joints 121 can be used to perform corresponding rotations, thereby satisfying various flexible operations on the end effector 400. Moreover, the coupled application of the rigid arm segment 110 and the flexible arm segment 120 further satisfies the effect of balancing the flexibility and rigidity requirements of the robotic arm.

[0034] like Figure 1 and Figure 6 As shown, in this embodiment, the rope drive mechanism 300 includes a frame 320 and a plurality of rope drive units 330 disposed on the frame 320. The plurality of rope drive units 330 are used to control the winding and unwinding states of a plurality of drive ropes.

[0035] Specifically, in this embodiment, the frame 320 is a multi-plate structure connected by multiple connecting columns, which allows the frame 320 to form a multi-layer area, so that the various components of the multiple rope drive units 330 can be installed in the corresponding area respectively, realizing the reasonable and compact installation of multiple rope drive units 330 and avoiding the space redundancy problem caused by complex mechanisms.

[0036] like Figures 1 to 4 As shown, in this embodiment, the rigid arm segment 110 includes a rigid first arm segment 111 and a rigid second arm segment 112. One end of the rigid first arm segment 111 is connected to the rigid tubular rod 200, and the other end of the rigid first arm segment 111 is rotatably connected to one end of the rigid second arm segment 112 via a gear rotating joint 130. The other end of the rigid second arm segment 112 is connected to the flexible arm segment 120. The flexible arm segment 120 includes a plurality of snake-bone joints 122 arranged sequentially along its arm length trajectory. Adjacent snake-bone joints 122 are rotatably connected via a rope-driven rotating joint 121. The drive rope passes sequentially through the rigid tubular rod 200, the rigid first arm segment 111, the gear rotating joint 130, the rigid second arm segment 112, and the plurality of snake-bone joints 122, so that a portion of the drive rope is connected to the end effector 400, while the remaining drive rope is connected to the end effector of the flexible arm segment 120.

[0037] After adopting the above configuration, the drive rope can pass through the entire rigid-flexible coupling arm 100. Therefore, when a part of the drive rope applies force to the end of the rigid-flexible coupling arm 100, it can drive the gear rotating joint 130 and multiple rope-driven rotating joints 121 to rotate accordingly. When another part of the drive rope applies force to the end effector 400, it can drive the end effector 400 to perform corresponding operation.

[0038] like Figure 2 and Figure 3 As shown, this embodiment of the gear rotation joint 130 includes a first gear plate 131, a second gear plate 132, a connecting rod 133, and a guide rope component 134. The two first gear plates 131 are located on opposite sides of the ends of the rigid first arm segment 111; the two second gear plates 132 are located on opposite sides of the ends of the rigid second arm segment 112. The two second gear plates 132 mesh with the two first gear plates 131 respectively, and the change in the meshing position of the two second gear plates 132 with the two first gear plates 131 is used to realize the rotation of the gear rotation joint 130. One end of the two connecting rods 133 is rotatably connected to the gear axial center of the two first gear plates 131 respectively, and the other end of the two connecting rods 133 is rotatably connected to the gear axial center of the two second gear plates 132 respectively. The guide rope component 134 is connected to the two connecting rods 133. The drive rope passes through the rigid first arm segment 111, passes through the guide rope component 134, and then passes through the rigid second arm segment 112.

[0039] After adopting the above configuration, when the rope drive mechanism 300 controls the drive rope to perform corresponding operations, a force will be generated on the gear rotation joint 130, causing the meshing position of the first gear plate 131 and the second gear plate 132 to change, thereby achieving both the rotation of the gear rotation joint 130 and the rigidity requirement of the rigid-flexible coupling arm 100.

[0040] Since the connecting rod 133 is connected to the first gear plate 131 and the second gear plate 132 respectively, even if the first gear plate 131 and the second gear plate 132 rotate relative to each other, the two can still maintain a tight meshing state through the connecting rod 133; and the setting of the guide rope component 134 can better guide the arrangement path of the drive rope.

[0041] like Figures 1 to 4 As shown, in this embodiment, the rigid-flexible coupling arm 100 is provided with an actuator rope passage 141 and an arm segment rope passage 142. The actuator rope passage 141 and the arm segment rope passage 142 pass through the rigid first arm segment 111, the rope guide component 134, the rigid second arm segment 112, and multiple snake joints 122 in sequence. A portion of the drive rope passes through multiple actuator rope passages 141 and is connected to the end effector 400 rope drive. The remaining drive rope passes through multiple arm segment rope passages 142 and is connected to the end effector rope drive of the flexible arm segment 120.

[0042] After adopting the above setting method, the function of the drive rope can be divided to ensure that multiple drive ropes can pass smoothly through the rigid-flexible coupling arm 100 as designed.

[0043] like Figures 2 to 5As shown, in this embodiment, the end effector 400 includes two rotatably connected grippers 410. One end of a drive rope 310 passes through an actuator rope passage 141, then around the rotatable connection portion 420 of one gripper 410, and passes through the other actuator rope passage 141, so that both ends of the drive rope 310 are connected to two rope drive units 330 respectively, and the drive rope is fixedly connected to the rotatable connection portion 420 of the gripper 410. One end of the other drive rope 310 passes through an actuator rope passage 141, then around the rotatable connection portion 420 of another gripper 410, and passes through the other actuator rope passage 141, so that both ends of the drive rope 310 are connected to two other rope drive units 330 respectively, and the drive rope 310 is fixedly connected to the rotatable connection portion 420 of the gripper 410.

[0044] After adopting the above configuration, the two grippers 410 will be controlled by two drive ropes respectively. Taking the control method of one gripper 410 as an example, at this time, one drive rope is actually connected and fixed to the rotation connection part 420 of the gripper 410 through its middle part. Therefore, when one rope drive unit 330 controls the tightening of this drive rope, the other rope drive unit 330 will control the loosening of this drive rope. At this time, not only is the rotation direction of the gripper 410 controlled, but also the rotation position of the gripper 410 is better maintained, thereby meeting the precise control requirements of the surgical procedure.

[0045] like Figure 1 , Figure 3 and Figure 4 As shown, in this embodiment, the actuator rope passage 141 is located on the outer side of the rigid-flexible coupling arm 100; the arm segment rope passage 142 is located on the middle part of the rigid-flexible coupling arm 100.

[0046] After adopting the above configuration, the actuator rope passage 141 and the boom section rope passage 142 can be reasonably and closely distributed.

[0047] like Figure 1 , Figure 3 and Figure 4 As shown, in this embodiment, the rigid-flexible coupling arm 100 is provided with a weight reduction channel 143, which passes through the rigid first arm segment 111, the guide rope component 134, the rigid second arm segment 112, and multiple snake bone joints 122 in sequence.

[0048] After adopting the above configuration, the weight reduction channel 143 is essentially a structure with through-holes in the rigid first arm segment 111, the guide rope component 134, the rigid second arm segment 112, and the multiple snake bone joints 122, so that the rigid first arm segment 111, the guide rope component 134, the rigid second arm segment 112, and the multiple snake bone joints 122 can have a lighter weight.

[0049] like Figure 6 As shown, this embodiment configures the rope drive unit 330 to include a drive motor 331, a transmission screw 332, a ball bearing seat 333 with a threaded hole, a guide rod 334, a guide wheel 335, and a drive rope. The drive motor 331 is used to drive the transmission screw 332 to rotate. The transmission screw 332 is threadedly connected to the ball bearing seat 333. The drive rope is connected to the ball bearing seat 333. The guide rod 334 is arranged parallel to the transmission screw 332 and passes through the ball bearing portion of the ball bearing seat 333. The drive rope passes around the guide wheel 335 and is then connected to the rope drive of the rigid-flexible coupling arm 100.

[0050] After adopting the above configuration, if the drive motor 331 controls the transmission screw 332 to rotate in one direction, it can control the ball bearing seat 333 to move downward along the guide direction of the guide rod 334, thereby achieving tensioning of the drive rope; similarly, if the drive motor 331 controls the transmission screw 332 to rotate in another direction, it can control the ball bearing seat 333 to move upward along the guide direction of the guide rod 334, thereby achieving relaxation of the drive rope.

[0051] The guide wheel 335 not only guides the drive rope to extend in the specified direction, but also makes the release and retraction of the drive rope smoother.

[0052] In addition, the ball bearing housing 333 is equivalent to integrating the guide rail and the ball bearing, thereby improving the overall system integration.

[0053] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A high-precision rigid-flexible coupling surgical robot for narrow natural cavities, characterized in that, Including rigid-flexible coupling arms, rigid tubular rods, and rope-driven mechanisms; The diameter of the rigid-flexible coupling arm is 2-3mm, and the rigid-flexible coupling arm includes a rigid arm segment and a flexible arm segment. One end of the rigid arm segment is connected to one end of the rigid tubular rod, and the other end of the rigid arm segment is connected to the flexible arm segment. A rope-driven gear rotation joint is provided between the two ends of the rigid arm segment. An end effector is installed at the end of the flexible arm segment away from the rigid arm segment, and multiple cable-driven rotary joints are arranged sequentially and separately along the arm length trajectory between the two ends of the flexible arm segment, with the rotation axes of adjacent cable-driven rotary joints being perpendicular to each other. The end of the rigid tubular rod away from the rigid-flexible coupling arm is connected to the rope drive mechanism; The multiple drive ropes of the rope drive mechanism pass through the rigid tubular rod and are respectively connected to the gear rotating joint and the multiple rope drive rotating joints. The rope drive mechanism includes a frame and multiple rope drive units mounted on the frame. The multiple rope drive units are used to control the extension and retraction states of multiple drive ropes. The rigid arm segment includes a rigid first arm segment and a rigid second arm segment. One end of the rigid first arm segment is connected to the rigid tubular rod, and the other end of the rigid first arm segment is rotatably connected to one end of the rigid second arm segment through the gear rotation joint. The other end of the rigid second arm segment is connected to the flexible arm segment. The flexible arm segment includes multiple snake-bone joints arranged sequentially along its arm length trajectory, and adjacent snake-bone joints are rotatably connected by the rope-driven rotary joint. The drive rope passes sequentially through the rigid tubular rod, the rigid first arm segment, the gear rotating joint, the rigid second arm segment, and multiple snake-bone joints, so that a portion of the drive rope is connected to the end effector rope drive, while the remaining drive rope is connected to the end rope drive of the flexible arm segment. The gear rotation joint includes a first gear plate, a second gear plate, a connecting rod, and a guide rope component; The two first gear plates are disposed on opposite sides of the end of the rigid first arm segment; Two second gear plates are disposed on opposite sides of the end of the rigid second arm segment. The two second gear plates mesh with the two first gear plates respectively. The change in the meshing position of the two second gear plates and the two first gear plates is used to realize the rotation of the gear rotation joint. One end of each of the two connecting rods is rotatably connected to the gear axial center of the two first gear plates, and the other end of each of the two connecting rods is rotatably connected to the gear axial center of the two second gear plates. The guide rope component is connected to the two connecting rods; The drive rope passes through the rigid first arm segment, then through the guide rope component, and finally through the rigid second arm segment; The rigid-flexible coupling arm is provided with an actuator rope passage and an arm segment rope passage; The actuator rope passage and the arm segment rope passage both pass sequentially through the rigid first arm segment, the rope guide component, the rigid second arm segment, and the multiple snake-bone joints; A portion of the drive ropes pass through multiple actuator rope passages and are connected to the end effector rope drive. The remaining drive ropes pass through multiple of the arm segment rope passages and are connected to the end rope drive of the flexible arm segment; The end effector includes two rotatably connected grippers; One end of one of the drive ropes passes through one of the actuator rope passages, then around the rotating connection of one of the grippers, and passes through another actuator rope passage, so that both ends of the drive rope are respectively connected to the two rope drive units, and the drive rope is fixedly connected to the rotating connection of the gripper. One end of the other drive rope passes through one of the actuator rope passages, then around the rotating connection of another gripper, and passes through another actuator rope passage, so that both ends of the drive rope are respectively connected to the other two rope drive units, and the drive rope is fixedly connected to the rotating connection of the gripper.

2. The high-precision rigid-flexible coupling surgical robot according to claim 1, characterized in that, The actuator rope passage is located near the outer side of the rigid-flexible coupling arm; The rope passage of the arm segment is located near the middle of the rigid-flexible coupling arm.

3. The high-precision rigid-flexible coupling surgical robot according to claim 1, characterized in that, The rigid-flexible coupling arm is provided with a weight reduction channel, which passes sequentially through the rigid first arm segment, the guide rope component, the rigid second arm segment, and multiple snake bone joints.

4. The high-precision rigid-flexible coupling surgical robot according to claim 1, characterized in that, The rope drive unit includes a drive motor, a transmission screw, a ball bearing seat with a threaded hole, a guide rod, a guide wheel, and the drive rope; The drive motor is used to drive the transmission screw to rotate. The transmission screw is threadedly connected to the ball bearing housing; The drive rope is connected to the ball bearing housing; The guide rod is arranged parallel to and opposite to the transmission screw, and the guide rod passes through the ball bearing portion of the ball bearing housing; The drive rope passes around the guide wheel and is connected to the rigid-flexible coupling arm rope drive.

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