Parallel robot platform based on composite driving of flexible cable and continuum

Abstract

The invention relates to a parallel robot platform based on composite driving of a flexible cable and a continuum, which comprises a support frame and a working platform suspended above the support frame, and the working platform is used for connecting an end effector; three sets of flexible continuum mechanical arms of the same structure are evenly arranged on the working platform in the circumferential direction of the working platform, the head ends of the three sets of flexible continuum mechanical arms are rotationally connected with the working platform through ball universal joint assemblies correspondingly, and the tail ends of the three sets of flexible continuum mechanical arms are connected with mechanical arm driving mechanisms correspondingly. According to the technical scheme, the interaction safety of the robot is improved, and the accuracy and stability of the end effector are enhanced while the flexibility of the continuum robot is kept.

Description

Technical Field

[0001] The invention relates to the field of robots, and in particular to a parallel robot platform based on flexible cable and continuum composite drive. Background Art

[0002] A parallel robot is a mechanical device based on a closed-loop motion chain structure, which is widely used in precision assembly, high-speed sorting, national defense science and technology and other fields. In order to realize the complex spatial movement of the end effector, the robot is often required to be able to achieve six-degree-of-freedom posture changes in space. Common six-degree-of-freedom parallel robots mostly adopt the Stewart configuration. The dynamic platform and the static platform are coordinated by six retractable connecting rods. The dynamic platform can reach different postures by controlling the six connecting rods to retract. It has the characteristics of high rigidity, high precision and fast response of the end effector. It can be used for motion simulation platforms, precise positioning, etc. This type of six-degree-of-freedom parallel robot needs to use six branches, and each branch is a rigid structure. In occasions such as medical surgery, a high-precision force feedback system is required to ensure its interactive safety.

[0003] The continuum robot is a new type of bionic robot inspired by the flexible animal structures in nature, such as elephant trunks and octopus tentacles. It is made of flexible and elastic materials, has the characteristics of high flexibility, high compliance and jointless structure, and can continuously change its shape under the action of the driver, thereby achieving a variety of actions such as bending and rotation. It has shown its unique advantages in the fields of search and rescue, industrial repair, etc. However, traditional multi-degree-of-freedom continuum robots are usually composed of multiple continuum segments connected in series, with complex driving principles. During operation, due to factors such as friction and tube gap, errors will continue to accumulate in the transmission of each continuum segment, resulting in reduced accuracy of the end effector.

[0004] Although some robots currently combine the advantages of both, there are still some areas to be improved. The patent with publication number CN108422413A discloses a flexible continuous parallel robot with variable stiffness. Although this invention patent has the characteristics of flexible movement, controllable stiffness, and strong adaptability, the driving component is easily damaged under continuous torsion and deformation, which affects the service life. The patent with publication number CN114800454A discloses a continuum robot based on a compliant Stewart parallel mechanism. Although this invention patent has high flexibility and strong anti-torsion ability, its kinematic model is complex and difficult to manufacture. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned drawbacks and provide a parallel robot platform based on flexible cable and continuum composite drive.

[0006] To achieve the above object, the present invention adopts the following technical scheme: comprising a support frame and a working platform suspended above the support frame, the working platform being used to connect an end effector; the working platform is evenly provided with three groups of flexible continuum mechanical arms of the same structure along its circumference, the head ends of the three groups of flexible continuum mechanical arms are rotatably connected to the working platform through ball head universal joint assemblies, and the ends of the three groups of flexible continuum mechanical arms are respectively connected to mechanical arm driving mechanisms; The mechanical arm driving mechanism includes a square frame body, a screw nut mechanism and a flexible cable driving mechanism arranged in the frame body, one end of the frame body is fixedly connected to the stepper motor mounting plate, and the other end of the frame body is provided with a continuum mounting plate movably connected to the frame body, and the continuum mounting plate is fixed to the end of the flexible continuum mechanical arm; The screw-nut mechanism includes a screw, one end of which is connected to a first stepper motor fixed on a stepper motor mounting plate, and the other end of which passes through the stepper motor mounting plate and the continuum mounting plate, and a first screw nut matched with the screw is fixed on the continuum mounting plate, and the first stepper motor drives the screw to rotate so that the continuum mounting plate is displaced along the axial direction of the screw to realize the displacement of the flexible continuum mechanical arm in the front-rear direction; The flexible cable driving mechanism includes a servo electric cylinder and a flexible cable, one end of the flexible cable is fixed to the push rod end of the servo electric cylinder, and the other end of the flexible cable passes through the flexible continuum robotic arm and is fixed to the head end of the flexible continuum robotic arm; the flexible cables and servo electric cylinders are respectively arranged in three groups, and the three groups of flexible cables respectively cause the flexible continuum robotic arm to deform under the driving cooperation of the three groups of servo electric cylinders to realize the pitch and deflection adjustment of the flexible continuum robotic arm.

[0007] The frame body is fixed on the driving mechanism support frame, one end of the driving mechanism support frame is hinged to the top of the support frame through a first hinge, and the other end of the driving mechanism support frame is connected to the angle adjustment mechanism; The angle adjustment mechanism includes a screw nut slider mechanism and a connecting rod. The screw nut slider mechanism is arranged on the layer plate of the support frame. The screw nut slider mechanism includes a ball screw, a screw nut seat matching the ball screw, a nut slide fixed on the screw nut seat and a second stepper motor for driving the ball screw to rotate; one end of the connecting rod is hinged to the nut slide through a second hinge, and the other end of the connecting rod is hinged to the drive mechanism support frame through a third hinge. The connecting rod, the drive mechanism support frame, the first hinge and the nut slide form a crank slider mechanism. When the second stepper motor drives the nut slide along the axial displacement of the ball screw through the ball screw, the connecting rod drives the drive mechanism support frame to rotate around the hinge axis of the first hinge to realize the adjustment of the pitch angle of the robot arm drive mechanism.

[0008] The screw nut slider mechanism also includes slide rails symmetrically arranged on both sides of the ball screw, sliders slidingly matched with the slide rails, and a connecting bracket fixed on the slider, wherein the connecting bracket is fixed to the nut slider.

[0009] The supporting frame is a triangular structure as a whole, including an upper triangular frame, a lower triangular frame and a column connecting the two. A layer plate parallel to the upper triangular frame and the lower triangular frame is provided between the upper triangular frame and the lower triangular frame. The layer plate is fixed to the column by installing a tripod. The bottom of the lower triangular frame is also covered with a base plate, and the bottom of the lower triangular frame is also provided with an adjustable foot.

[0010] The flexible continuum robotic arm is an integrally constructed tubular annular continuum, which is formed by connecting multiple sections of identical annular bodies, and each section of the annular body is annularly cut with three equal arcs. One end of the flexible continuum robotic arm is connected to the ball head universal joint assembly through a first flange, and the other end of the flexible continuum robotic arm is fixed to the continuum mounting plate of the robotic arm drive mechanism through a second flange; the flexible continuum robotic arm is evenly arranged with three groups of flexible cable holes along its circumference, and the three groups of flexible cable holes are all arranged through the flexible continuum robotic arm.

[0011] The ball head universal joint assembly comprises a ball head rod and a ball head seat which cooperate with each other, the ball head seat is fixed to the working platform, and the ball head rod is connected to the flexible continuum mechanical arm through a connecting piece; The connecting piece includes a rod-shaped connecting head and a third flange. A first threaded hole is provided at one end of the connecting head, and the first threaded hole is matched and connected with the threaded section on the ball head rod. A second threaded hole is provided at the other end of the connecting head, and the second threaded hole is fixed to the third flange by bolts. The third flange is fixed to the first flange at the end of the flexible continuum robotic arm.

[0012] The working platform is a triangular block structure as a whole, and its three corners respectively form U-shaped ear seats for fixing the ball head seat. Connecting shafts are symmetrically arranged on the outer wall of the ball head seat, and the two ends of the connecting shaft are respectively connected to the ball head seat and the U-shaped ear seat through miniature bearings.

[0013] A servo electric cylinder mounting plate and a servo electric cylinder push rod mounting plate are arranged in sequence between the stepper motor mounting plate and the continuum mounting plate, wherein: the continuum mounting plate and the servo electric cylinder push rod mounting plate are fixedly connected by a first connecting plate, and the servo electric cylinder push rod mounting plate and the servo electric cylinder mounting plate are fixedly connected by a second connecting plate, and the servo electric cylinder push rod mounting plate and the servo electric cylinder mounting plate are respectively provided with a second screw nut and a third screw nut matching with the screw, and the continuum mounting plate, the servo electric cylinder push rod mounting plate and the servo electric cylinder mounting plate form a component that moves as a whole on the screw.

[0014] The cylinder body end of the servo electric cylinder is fixed on the servo electric cylinder mounting plate, and the push rod end of the servo electric cylinder passes through the servo electric cylinder push rod mounting plate and is fixed to the flexible cable through a flexible cable connector; through holes are respectively provided at both ends of the flexible cable connector, wherein the through hole at one end is used to fix the flexible cable, and a screw joint is installed at the through hole at the other end, and the screw joint is threadedly connected to the push rod of the servo electric cylinder.

[0015] The frame body includes guide columns arranged perpendicular to the four corners of the stepper motor mounting plate and a cross bar connecting two adjacent guide columns. The four corners of the servo electric cylinder mounting plate, the servo electric cylinder push rod mounting plate and the continuum mounting plate are respectively provided with square notches for avoiding the guide columns; the first stepper motor is arranged in two groups, and the two groups of first stepper motors are fixed on the stepper motor mounting plate in a diagonal direction.

[0016] The beneficial effects of the present invention are: 1. The flexible continuum robot arm of the present invention has four degrees of freedom. In addition to the pitch and yaw degrees of freedom in the space of the robot arm itself, two redundant degrees of freedom are introduced through the screw nut mechanism and the angle adjustment mechanism, which is more flexible than the traditional two-degree-of-freedom continuum. At the same time, this structure can enrich the motion posture of the end effector, so that the end effector can perform more complex spatial motion tasks, significantly improving the adaptability and execution ability of the robot in various application scenarios.

[0017] 2. The present invention realizes the six-degree-of-freedom motion of the end effector in space by adopting a parallel mechanism, which is a flexible motion chain driven by three flexible cables and a continuum compound drive in parallel, thereby improving the passive compliance of the robot and making the robot have better interactive safety in medical operations and other occasions.

[0018] 3. The present invention adopts a composite drive system combining a stepper motor, a servo electric cylinder and a flexible cable, so that the robot can have excellent precision and flexibility when performing tasks.

[0019] 4. The present invention replaces the motion branch of the parallel robot with a two-degree-of-freedom continuum robot, so that each motion chain in the parallel structure can be designed to be shorter and simpler, thereby improving the kinematic performance in terms of accuracy and dynamic performance, reducing the accumulation of errors, and improving the stability and reliability of the robot in precision operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The three-dimensional structure of the present invention is shown in FIG. Figure 1 ; Figure 2 The three-dimensional structure of the present invention is shown in FIG. Figure 2 ; Figure 3 It is a schematic diagram of the working state of the present invention; Figure 4 yes Figure 3 A magnified view of part A; Figure 5 It is a structural schematic diagram of the support frame of the present invention; Figure 6 It is a structural schematic diagram of the working platform of the present invention; Figure 7 It is a schematic diagram of the structure of the flexible continuum mechanical arm and the ball head rod of the present invention; Figure 8 yes Figure 7 Schematic diagram of the decomposition structure; Fig. 9 It is a schematic diagram of the connection between the flexible continuum mechanical arm and the flexible cable of the present invention; Fig.10 It is a schematic diagram of the overall structure of the mechanical arm driving mechanism of the present invention; Fig.11 The internal structure of the mechanical arm drive mechanism of the present invention is schematically shown in FIG. Figure 1 ; Fig.12 The internal structure of the mechanical arm drive mechanism of the present invention is schematically shown in FIG. Figure 2 ; Fig.13 It is a schematic diagram of the exploded structure of the mechanical arm driving mechanism of the present invention; Fig.14 This is the use state of the screw nut mechanism of the present invention. Figure 1 ; Fig.15 This is the use state of the screw nut mechanism of the present invention. Figure 2 ; Fig.16 It is a structural schematic diagram of a single-group angle adjustment mechanism of the present invention.

[0021] The marks in the above drawings are: support frame 1, upper triangular frame 11, lower triangular frame 12, column 13, layer plate 14, mounting bracket 15, bottom plate 16, adjustable foot 17, first hinge 18, working platform 2, U-shaped ear seat 21, flexible continuum robot arm 3, first flange 31, second flange 32, flexible cable hole 33, ball head universal joint assembly 4, ball head rod 41, ball head seat 42, connecting shaft 421, miniature bearing 422, connecting piece 43, connecting head 431, third flange 432, robot arm drive mechanism 5, frame body 501, guide column 5011, cross bar 5012, stepper motor mounting plate 502, servo Electric cylinder mounting plate 503, servo electric cylinder push rod mounting plate 504, continuum mounting plate 505, first connecting plate 506, second connecting plate 507, screw 511, first stepping motor 512, first screw nut 513, second screw nut 514, third screw nut 515, servo electric cylinder 521, flexible cable 522, flexible cable connector 523, screw joint 524, drive mechanism support frame 6, angle adjustment mechanism 7, connecting rod 71, second hinge 711, third hinge 712, ball screw 72, screw nut seat 73, nut slide plate 74, second stepping motor 75, slide rail 76, slider 77, connecting bracket 78. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings: like Figure 1 , Figure 2 , Figure 3 , Figure 4 A parallel robot platform based on a composite drive of a flexible cable and a continuum is shown, comprising a support frame 1 and a working platform 2 suspended above the support frame 1, the working platform 2 being used to connect an end effector; the working platform 2 is evenly provided with three groups of flexible continuum robotic arms 3 of the same structure along its circumference, the head ends of the three groups of flexible continuum robotic arms 3 are rotatably connected to the working platform 2 through ball head universal joint assemblies 4, and the ends of the three groups of flexible continuum robotic arms 3 are respectively connected to a robotic arm driving mechanism 5.

[0023] Further, such as Figure 5As shown, the support frame 1 serves as the supporting part of the entire parallel robot platform and bears the entire weight of the parallel robot platform. In this embodiment, the support frame 1 is arranged in a triangular structure. Specifically, the support frame 1 is a triangular structure as a whole, including an upper triangular frame 11, a lower triangular frame 12, and a column 13 connecting the two. The support frame 1 is made of profiles. A layer plate 14 parallel to the upper triangular frame 11 and the lower triangular frame 12 is also provided between the upper triangular frame 11 and the lower triangular frame 12, and the layer plate 14 is fixed to the column 13 by installing a tripod 15. The bottom of the lower triangular frame 12 is also covered with a base plate 16, which is made of sheet metal for easy storage of drivers, power supplies and other accessories. The bottom of the lower triangular frame 12 is also provided with an adjustable foot 17, which can be adjusted according to the ground conditions, thereby ensuring the levelness of the entire parallel robot platform and flexibly adapting to different working environments.

[0024] Further, such as Figure 6 As shown, the working platform 2 is a triangular block structure as a whole, and its three corners respectively form U-shaped ear seats 21 for fixing the ball head seat 42. In order to avoid collision between the working platform 2 and the ball head seat 42 during movement, the distance between the two ear plates in the U-shaped ear seat 21 should be slightly larger than the outer diameter of the ball head seat 42, and the bottom surface of the U-shaped ear seat 21 is designed to be arc-shaped. A through hole is opened in the center of the working platform 2 to reduce the weight of the working platform 2 and achieve a lightweight design. In actual work, according to different tasks and needs, end effectors with different functions such as grasping, handling, and assembly can be connected to the working platform 2 to complete various tasks.

[0025] Further, such as Figure 7 As shown, the flexible continuum robot arm 3 is an integrally constructed tubular annular continuum, which is connected by multiple identical annular bodies, and each annular body is annularly cut with three equal arcs, so that the continuum has both excellent bending performance and axial tensile stiffness. Preferably, the flexible continuum robot arm 3 is made of elastic metal material, such as nickel-titanium alloy, and the manufacturing process selects laser cutting or wire cutting. One end of the flexible continuum robot arm 3 is connected to the ball head universal joint assembly 4 through the first flange 31, and the other end of the flexible continuum robot arm 3 is fixed to the continuum mounting plate 505 of the robot arm drive mechanism 5 through the second flange 32. In this embodiment, the first flange 31 is circular, and the second flange 32 is triangular, and the fillet treatment is performed, which reduces the influence of stress concentration and can effectively avoid the breakage of the robot arm. The flexible continuum robot arm 3 is evenly arranged with three groups of flexible cable holes 33 along its circumference, and the three groups of flexible cable holes 33 are all set through the flexible continuum robot arm 3.

[0026] When working, Figure 3 , Figure 4As shown, three groups of flexible continuum robotic arms 3 are driven separately by three groups of flexible cables 522, and all produce a certain angle of deformation. The ball head rod 41 corresponding to each group of robotic arm driving mechanism 5 transmits the motion to the corresponding ball head seat 42. The three motion chains cooperate with each other to jointly drive the working platform 2, so that the end effector fixed on the working platform 2 can complete complex spatial motion.

[0027] Further, such as Figure 6 , Figure 8 , Fig. 9 As shown, the ball head universal joint assembly 4 includes a ball head rod 41 and a ball head seat 42 that cooperate with each other, wherein: the ball head seat 42 is fixed to the working platform 2, and the ball head rod 41 is connected to the flexible continuum robot arm 3 through a connecting piece 43.

[0028] Specifically, the connector 43 includes a rod-shaped connector 431 and a third flange 432. A first threaded hole is provided at one end of the connector 431, and the first threaded hole is matched and connected with the threaded section on the ball head rod 41. A second threaded hole is provided at the other end of the connector 431, and the second threaded hole is fixed to the third flange 432 by bolts. The third flange 432 is fixed to the first flange 31 at the end of the flexible continuum mechanical arm 3 by bolts. A bolt hole is provided at the center of the third flange 432 for connecting the third flange 432 and the connector 431. Three through holes are also provided on the third flange 432. The positions of the three through holes coincide with the positions of the three groups of flexible cable holes 33, providing space for fixing the flexible cable 522 at the head end of the flexible continuum mechanical arm 3.

[0029] Specifically, a connecting shaft 421 is symmetrically arranged on the outer wall of the ball head seat 42, and the two ends of the connecting shaft 421 are respectively connected to the ball head seat 42 and the ear plate on one side of the U-shaped ear seat 21 through micro bearings 422. That is, in order to fix the ball head seat 42, stepped holes are designed on the two ear plates of the U-shaped ear seat 21, and the stepped holes are used to install the micro bearings 422 to prevent the bearings from axial movement. Similarly, the same stepped holes are also arranged on the cylindrical surface of the ball head seat 42 for installing the micro bearings 422. The ball head seat 42 is fixed in the middle of the two ear plates of the U-shaped ear seat 21 through the connecting shaft 421, so as to achieve free rotation around the connecting shaft 421. This design makes the working platform 2 more flexible and capable of performing more complex movements.

[0030] Furthermore, the robot arm driving mechanism 5 includes a square frame body 501 and a screw nut mechanism and a flexible cable driving mechanism arranged in the frame body 501 .

[0031] Specifically, Fig.10 , Fig.11 , Fig.12 , Fig.13As shown, one end of the frame body 501 is fixedly connected to the stepper motor mounting plate 502, and the other end of the frame body 501 is provided with a continuum mounting plate 505 movably connected to the frame body 501, and the continuum mounting plate 505 is fixed to the end of the flexible continuum mechanical arm 3. A servo electric cylinder mounting plate 503 and a servo electric cylinder push rod mounting plate 504 are also arranged in sequence between the stepper motor mounting plate 502 and the continuum mounting plate 505, wherein: the continuum mounting plate 505 and the servo electric cylinder push rod mounting plate 504 are fixedly connected by a first connecting plate 506, and the servo electric cylinder push rod mounting plate 504 and the servo electric cylinder mounting plate 503 are fixedly connected by a second connecting plate 507, and the continuum mounting plate 505, the servo electric cylinder push rod mounting plate 504, and the servo electric cylinder mounting plate 503 form a component that moves as a whole on the screw rod 511.

[0032] The frame body 501 includes guide columns 5011 arranged perpendicularly at the four corners of the stepper motor mounting plate 502 and a crossbar 5012 connecting two adjacent guide columns 5011. The top surface and front and rear surfaces of the frame body 501 are provided with baffles. The four corners of the servo electric cylinder mounting plate 503, the servo electric cylinder push rod mounting plate 504 and the continuum mounting plate 505 are respectively provided with square notches for avoiding the guide columns 5011. Two groups of first stepper motors 512 are provided, and the two groups of first stepper motors 512 are fixed on the stepper motor mounting plate 502 in a diagonal direction.

[0033] Specifically, the screw-nut mechanism includes a screw 511, one end of which is connected to a first stepper motor 512 fixed on a stepper motor mounting plate 502, and the other end of the screw 511 passes through the stepper motor mounting plate 502, the servo electric cylinder mounting plate 503, the servo electric cylinder push rod mounting plate 504 and the continuum mounting plate 505 in sequence, and a first screw nut 513 matching with the screw 511 is fixed on the continuum mounting plate 505, and a second screw nut 514 and a third screw nut 515 matching with the screw 511 are respectively provided on the servo electric cylinder push rod mounting plate 504 and the servo electric cylinder mounting plate 503, and the first stepper motor 512 drives the screw 511 to rotate so that the continuum mounting plate 505 is displaced along the axial direction of the screw 511 to realize the displacement of the flexible continuum robot arm 3 in the front and rear directions.

[0034] Specifically, the flexible cable driving mechanism includes a servo electric cylinder 521 and a flexible cable 522, one end of the flexible cable 522 is fixed to the push rod end of the servo electric cylinder 521, and the other end of the flexible cable 522 passes through the flexible continuum mechanical arm 3 and is fixed to the head end of the flexible continuum mechanical arm 3. The flexible cables 522 and the servo electric cylinder 521 are respectively provided in three groups, and the three groups of flexible cables 522 are respectively driven and cooperated with the three groups of servo electric cylinders 521 to deform the flexible continuum mechanical arm 3 to achieve the pitch and yaw adjustment of the flexible continuum mechanical arm 3.

[0035] The cylinder end of the servo electric cylinder 521 is fixed on the servo electric cylinder mounting plate 503, and the push rod end of the servo electric cylinder 521 passes through the servo electric cylinder push rod mounting plate 504 and is fixed to the flexible rope 522 through the flexible rope connector 523. Preferably, the diameter of the through hole on the servo electric cylinder push rod mounting plate 504 for the push rod of the servo electric cylinder 521 to pass through is slightly larger than the diameter of the push rod of the servo electric cylinder 521, so as to ensure that a proper clearance fit is formed between the push rod and the hole wall to prevent excessive wear. Through holes are respectively provided at both ends of the flexible rope connector 523, and the through hole at one end is used to fix the flexible rope 522. The flexible rope 522 is fixed to the flexible rope connector 523 by knotting or adding a metal block, and a screw joint 524 is installed at the through hole at the other end, and the screw joint 524 is threadedly connected to the push rod of the servo electric cylinder 521.

[0036] Further, the frame body 501 is fixed on the driving mechanism support frame 6, one end of the driving mechanism support frame 6 is hinged to the top of the support frame 1 through the first hinge 18, and the other end of the driving mechanism support frame 6 is connected to the angle adjustment mechanism 7. In this embodiment, the first hinge 8 is composed of two U-shaped hinges, and the two U-shaped hinges can rotate relative to each other. The U-shaped hinge at the upper end is fixed to the driving mechanism support frame 6, and the U-shaped hinge at the lower end is fixed to the upper triangular frame 11 of the support frame 1. Specifically, a fixed block is fixed in the profile groove of the upper triangular frame 11, and the top of the fixed block is fixed to the U-shaped hinge at the lower end by bolts. Preferably, each side of the upper triangular frame 11 is provided with two fixed blocks, a total of six fixed blocks, and correspondingly, six first hinges are also provided. The angle adjustment mechanism 7 is provided to increase a rotational degree of freedom for the flexible continuum manipulator 3, so that the entire parallel robot platform can achieve more complex movements. The angle adjustment mechanism 7 is installed between the support frame 1 and the manipulator drive mechanism 5, and can achieve an angle adjustment of about 0 to 45°.

[0037] Specifically, Fig.16 As shown, the angle adjustment mechanism 7 includes a screw nut slider mechanism and a connecting rod 71. The screw nut slider mechanism is arranged on the layer plate 14 of the support frame 1, and the layer plate 14 is rounded at the position where stress concentration or easy to break may occur. The screw nut slider mechanism includes a ball screw 72, a screw nut seat 73 matched with the ball screw 72, a nut slide plate 74 fixed on the screw nut seat 73, and a second stepping motor 75 driving the ball screw 72 to rotate; the screw nut slider mechanism also includes a slide rail 76 symmetrically arranged on both sides of the ball screw 72, a slide block 77 forming a sliding fit with the slide rail 76, and a connecting bracket 78 fixed on the slide block 77, and the connecting bracket 78 is fixed to the nut slide plate 74. The structure not mentioned in the screw nut slider mechanism can refer to the prior art.

[0038] One end of the connecting rod 71 is hinged to the nut slide 74 through the second hinge 711, and the other end of the connecting rod 71 is hinged to the driving mechanism support frame 6 through the third hinge 712. The main body of the connecting rod 71 in this embodiment adopts an "I"-shaped design, which not only reduces the weight of the connecting rod, but also enhances its bending strength. The second hinge 711 and the third hinge 712 are both U-shaped hinges. The connecting rod 71, the driving mechanism support frame 6, the first hinge 18 and the nut slide 74 form a crank slider mechanism. When the second stepper motor 75 drives the nut slide 74 to move along the axial direction of the ball screw 72 through the ball screw 72, the connecting rod 71 drives the driving mechanism support frame 6 to rotate around the hinge axis of the first hinge 18 to achieve the adjustment of the pitch angle of the robot drive mechanism 5, and finally achieves the adjustment of the pitch angle of the flexible continuum robot arm 3.

[0039] The working principle of the present invention is as follows: 1. The direction of the rope.

[0040] One end of the flexible rope is connected to the push rod end of the servo electric cylinder, and the other end of the flexible rope passes through the continuum mounting plate, the second flange, the flexible continuum mechanical arm and the first flange in sequence and is then fixed on the first flange.

[0041] 2. The working principle of the flexible cable drive mechanism.

[0042] When the servo electric cylinder is working, the push rod of the servo electric cylinder will pull the flexible cable to expand and contract synchronously, and transmit the force to the head end of the flexible continuum robot arm, so that the flexible continuum robot arm will deform and drive it to move. The flexible continuum robot arm can bend in multiple directions at a certain angle under the cooperative drive of the three sets of servo electric cylinders.

[0043] 3. Working principle of screw-nut mechanism.

[0044] The first stepper motor drives the lead screw to rotate, thereby driving the corresponding continuum mounting plate, servo electric cylinder push rod mounting plate, and servo electric cylinder mounting plate to move synchronously through the first lead screw nut, the second lead screw nut, and the third lead screw nut on the lead screw, thereby driving the flexible continuum robot arm to move forward or backward, such as Fig.14 , Fig.15 shown.

[0045] 4. Working principle of angle adjustment mechanism.

[0046] The second stepper motor drives the ball screw to rotate, thereby driving the nut slide to move through the screw nut seat on the ball screw. When the nut slide moves, the connecting rod will drive the driving mechanism support frame to rotate around the first hinge, thereby realizing the pitch adjustment of the robot arm driving mechanism.

[0047] In summary, the present invention designs a parallel robot platform based on a composite drive of flexible cables and continuum based on a continuum configuration, which consists of three independent continuous motion chains and has a total of six degrees of freedom. Each flexible continuum robotic arm also introduces additional degrees of freedom of movement and rotation, so that it has four degrees of freedom, thereby realizing the complex movement of the end effector in space by introducing redundant degrees of freedom. The present invention has good innovation in the design of continuum robot mechanisms, which not only improves the interactive safety of the robot, but also enhances the accuracy and stability of the end effector while retaining the flexibility of the continuum robot.

[0048] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A parallel robot platform based on flexible cable and continuum composite drive, characterized by: The invention comprises a support frame (1) and a working platform (2) suspended above the support frame (1), wherein the working platform (2) is used to connect an end effector; the working platform (2) is evenly provided with three groups of flexible continuum mechanical arms (3) of the same structure along its circumference, the head ends of the three groups of flexible continuum mechanical arms (3) are rotatably connected to the working platform (2) via ball head universal joint assemblies (4), and the ends of the three groups of flexible continuum mechanical arms (3) are respectively connected to mechanical arm driving mechanisms (5); The mechanical arm driving mechanism (5) comprises a square frame body (501), a screw nut mechanism and a flexible cable driving mechanism arranged in the frame body (501), one end of the frame body (501) is fixedly connected to the stepping motor mounting plate (502), and the other end of the frame body (501) is provided with a continuum mounting plate (505) movably connected to the frame body (501), and the continuum mounting plate (505) is fixed to the end of the flexible continuum mechanical arm (3); The screw-nut mechanism comprises a screw (511), one end of the screw (511) is connected to a first stepper motor (512) fixed on a stepper motor mounting plate (502), the other end of the screw (511) passes through the stepper motor mounting plate (502) and the continuum mounting plate (505), and a first screw nut (513) matched with the screw (511) is fixed on the continuum mounting plate (505), the first stepper motor (512) drives the screw (511) to rotate so as to cause the continuum mounting plate (505) to be displaced axially along the screw (511) to achieve displacement of the flexible continuum mechanical arm (3) in the front-rear direction; The flexible cable drive mechanism comprises a servo electric cylinder (521) and a flexible cable (522); one end of the flexible cable (522) is fixed to the push rod end of the servo electric cylinder (521); the other end of the flexible cable (522) passes through the flexible continuum mechanical arm (3) and is fixed to the head end of the flexible continuum mechanical arm (3); three groups of flexible cables (522) and servo electric cylinders (521) are respectively provided; the three groups of flexible cables (522) respectively cause the flexible continuum mechanical arm (3) to deform under the driving cooperation of the three groups of servo electric cylinders (521) to achieve pitch and deflection adjustment of the flexible continuum mechanical arm (3).

2. The parallel robot platform based on flexible cable and continuum composite drive according to claim 1 is characterized in that: The frame body (501) is fixed on the driving mechanism support frame (6), one end of the driving mechanism support frame (6) is hinged to the top of the support frame (1) via a first hinge (18), and the other end of the driving mechanism support frame (6) is connected to the angle adjustment mechanism (7); The angle adjustment mechanism (7) comprises a screw nut slider mechanism and a connecting rod (71); the screw nut slider mechanism is arranged on a layer plate (14) of the support frame (1); the screw nut slider mechanism comprises a ball screw (72), a screw nut seat (73) matched with the ball screw (72), a nut slide plate (74) fixed on the screw nut seat (73), and a second stepping motor (75) for driving the ball screw (72) to rotate; one end of the connecting rod (71) is hingedly connected to the nut slide plate (74) via a second hinge (711). The other end of the connecting rod (71) is hinged to the driving mechanism support frame (6) through a third hinge (712); the connecting rod (71), the driving mechanism support frame (6), the first hinge (18) and the nut slide plate (74) form a crank slider mechanism; when the second stepping motor (75) drives the nut slide plate (74) to move along the axial direction of the ball screw (72) through the ball screw (72), the connecting rod (71) drives the driving mechanism support frame (6) to rotate around the hinge axis of the first hinge (18) to achieve adjustment of the pitch angle of the robot arm driving mechanism (5).

3. The parallel robot platform based on flexible cable and continuum composite drive according to claim 2 is characterized in that: The screw nut slider mechanism further comprises slide rails (76) symmetrically arranged on both sides of the ball screw (72), a slider (77) slidingly matched with the slide rails (76), and a connecting bracket (78) fixed to the slider (77); the connecting bracket (78) is fixed to the nut slider (74).

4. The parallel robot platform based on flexible cable and continuum composite drive according to claim 1 is characterized in that: The support frame (1) is of a triangular structure as a whole, comprising an upper triangular frame (11), a lower triangular frame (12) and a column (13) connecting the upper triangular frame (11) and the lower triangular frame (12). A layer plate (14) parallel to the upper triangular frame (11) and the lower triangular frame (12) is provided between the upper triangular frame (11) and the lower triangular frame (12). The layer plate (14) is fixed to the column (13) by means of a mounting bracket (15). The bottom of the lower triangular frame (12) is also covered with a bottom plate (16), and the bottom of the lower triangular frame (12) is also provided with an adjustable foot (17).

5. The parallel robot platform based on flexible cable and continuum composite drive according to claim 1 is characterized in that: The flexible continuum robot arm (3) is an integrally constructed tubular annular continuum, which is formed by connecting a plurality of identical annular bodies, each of which is annularly cut with three equal arcs. One end of the flexible continuum robot arm (3) is connected to a ball head universal joint assembly (4) via a first flange (31), and the other end of the flexible continuum robot arm (3) is fixed to a continuum mounting plate (505) of a robot arm driving mechanism (5) via a second flange (32). The flexible continuum robot arm (3) is evenly provided with three groups of flexible cable holes (33) along its circumference, and the three groups of flexible cable holes (33) are all arranged through the flexible continuum robot arm (3).

6. The parallel robot platform based on flexible cable and continuum composite drive according to claim 1 is characterized in that: The ball head universal joint assembly (4) comprises a ball head rod (41) and a ball head seat (42) that cooperate with each other, the ball head seat (42) is fixed to the working platform (2), and the ball head rod (41) is connected to the flexible continuum mechanical arm (3) via a connecting piece (43); The connecting member (43) comprises a rod-shaped connecting head (431) and a third flange (432); one end of the connecting head (431) is provided with a first threaded hole, and the first threaded hole is matched and connected with the threaded section on the ball head rod (41); the other end of the connecting head (431) is provided with a second threaded hole, and the second threaded hole is fixed to the third flange (432) by bolts; the third flange (432) is fixed to the first flange (31) at the end of the flexible continuum robot arm (3).

7. The parallel robot platform based on flexible cable and continuum composite drive according to claim 6 is characterized in that: The working platform (2) is an overall triangular block structure, and its three corners respectively form U-shaped ear seats (21) for fixing the ball head seat (42). The outer wall of the ball head seat (42) is symmetrically provided with connecting shafts (421), and the two ends of the connecting shaft (421) are respectively connected to the ball head seat (42) and the U-shaped ear seat (21) through micro bearings (422).

8. The parallel robot platform based on flexible cable and continuum composite drive according to claim 1 is characterized in that: A servo electric cylinder mounting plate (503) and a servo electric cylinder push rod mounting plate (504) are arranged in sequence between the stepper motor mounting plate (502) and the continuum mounting plate (505), wherein: the continuum mounting plate (505) and the servo electric cylinder push rod mounting plate (504) are fixedly connected via a first connecting plate (506), and the servo electric cylinder push rod mounting plate (504) and the servo electric cylinder mounting plate (503) are fixedly connected via a second connecting plate (507), and a second screw nut (514) and a third screw nut (515) which match the screw (511) are respectively arranged on the servo electric cylinder push rod mounting plate (504) and the servo electric cylinder mounting plate (503), and the continuum mounting plate (505), the servo electric cylinder push rod mounting plate (504), and the servo electric cylinder mounting plate (503) form a component that moves as a whole on the screw (511).

9. The parallel robot platform based on flexible cable and continuum composite drive according to claim 8, characterized in that: The cylinder end of the servo electric cylinder (521) is fixed on the servo electric cylinder mounting plate (503), and the push rod end of the servo electric cylinder (521) passes through the servo electric cylinder push rod mounting plate (504) and is fixed to the flexible rope (522) through a flexible rope connector (523); through holes are respectively provided at both ends of the flexible rope connector (523), wherein the through hole at one end is used to fix the flexible rope (522), and a screw joint (524) is installed at the through hole at the other end, and the screw joint (524) is threadedly connected to the push rod of the servo electric cylinder (521).

10. The parallel robot platform based on flexible cable and continuum composite drive according to claim 8, characterized in that: The frame body (501) comprises guide columns (5011) arranged at four corners perpendicular to the stepper motor mounting plate (502) and a crossbar (5012) connecting two adjacent guide columns (5011); the servo electric cylinder mounting plate (503), the servo electric cylinder push rod mounting plate (504) and the continuum mounting plate (505) are respectively provided with square notches at four corners for avoiding the guide columns (5011); two groups of the first stepper motors (512) are arranged in total, and the two groups of the first stepper motors (512) are fixed on the stepper motor mounting plate (502) in a diagonal direction.

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