A flexible mechanical arm joint

Abstract

The present disclosure provides a flexible mechanical arm joint, which has a first side wall and a third side wall that are arranged opposite to each other and a second side wall and a fourth side wall that are arranged opposite to each other. The ends of the first and third side walls serve as rolling contact surfaces of adjacent joints in the flexible mechanical arm. The rolling contact surface is a stepped inner and outer contact curved surface, which is used to prevent torsion between the two joints. The inner contact curved surface located at one end of the same side wall protrudes from the outer contact curved surface, and the outer contact curved surface located at the other end of the side wall protrudes from the inner contact curved surface. The second and fourth side walls are respectively provided with driving member holes for the driving member of the flexible mechanical arm to pass through; a restraining rope is connected between adjacent joints, which is arranged in a cross shape on the outside of the first and third side walls, and the rope length of the restraining rope is unchanged and cannot be stretched, which is used to ensure close contact between adjacent joints, thereby improving the continuity of the flexible mechanical arm when bending. The flexible mechanical arm joint can improve the motion performance and structural stability of the flexible mechanical arm.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible arms, and in particular relates to a flexible mechanical arm joint. Background Art

[0002] Flexible robotic arms are an important research direction in the field of robotics in recent years. Compared with traditional rigid robotic arms, flexible robotic arms have greater flexibility and adaptability, can work in complex or confined spaces, and can interact with humans more safely. Although flexible robotic arms have many advantages, they still face a series of technical challenges in practical applications. Flexible robotic arms are often composed of multiple flexible hinge structures in series. Due to the defects of material properties and hinge structures, most flexible robotic arms have poor torsion resistance. In addition, flexible robots based on traditional rolling contact joints also have poor shear resistance. Once the flexible arm collides with the outside world, unpredictable micro-motion will occur, which is also the main reason for the poor motion accuracy of the flexible robot. The low-precision motion performance limits the application of flexible arms in delicate operations such as medical treatment and rescue. Summary of the invention

[0003] The present disclosure aims to solve one of the technical problems in the related art at least to some extent.

[0004] To this end, a flexible robotic arm joint provided in an embodiment of the present disclosure can enhance the anti-shear and anti-torsion capabilities of the flexible robotic arm.

[0005] In order to achieve the above objectives, the present disclosure adopts the following technical solutions:

[0006] The present disclosure provides a flexible robotic arm joint, the joint having a first side wall and a third side wall arranged opposite to each other and a second side wall and a fourth side wall arranged opposite to each other, the ends of the first side wall and the third side wall serving as rolling contact surfaces of adjacent joints in the flexible robotic arm, the rolling contact surface being an inner and outer contact curved surface in a stepped shape, for preventing twisting between the two joints, the inner contact curved surface at one end of the same side wall protruding from the outer contact curved surface, the outer contact curved surface at the other end of the side wall protruding from the inner contact curved surface, the second side wall and the fourth side wall are respectively provided with driving member holes for the driving member of the flexible robotic arm to pass through; a restraining rope is connected between adjacent joints, the restraining rope is cross-laid on the outer sides of the first side wall and the third side wall, and the rope length of the restraining rope is unchanged and cannot be stretched, for ensuring close contact between adjacent joints, thereby improving the continuity of the flexible robotic arm when bending.

[0007] In some embodiments, the number of the restraint ropes provided in the flexible robotic arm is 1, 2 or 4.

[0008] In some embodiments, in two mating joints, a small gap exists between the side surface of the inner contact curved surface and the side surface of the outer contact curved surface to reduce internal friction when the flexible robotic arm is bent.

[0009] In some embodiments, four constraint rope holes arranged along the direction of their respective wall thickness are respectively formed on the first side wall and the third side wall, the first constraint rope hole and the third constraint rope hole are diagonally arranged, and the second constraint rope hole and the fourth constraint rope hole are diagonally arranged, and the constraint rope is connected between the first constraint rope hole and the third constraint rope hole of two adjacent joints, and between the second constraint rope hole and the fourth constraint rope hole.

[0010] In some embodiments, a boss is provided at a pair of diagonally arranged restraint rope holes on the same side wall of the joint to avoid contact between the restraint ropes at the intersection.

[0011] In some embodiments, the shapes of the inner contact curved surface and the outer contact curved surface of the joint end are determined according to the following steps:

[0012] The center of the third constraint rope hole in the first joint is taken as the coordinate origin, the straight line where the center line of the third constraint rope hole and the second constraint rope hole in the first joint is located is taken as the x-axis, and the line parallel to the axial direction of the flexible mechanical arm is taken as the y-axis, and a geometric relationship model is established with the first constraint rope hole and the fourth constraint rope hole in the second joint, and the contact surface close to the fourth constraint rope hole and the first constraint rope hole in the first joint is recorded as the first contact surface, and its projection curve on the xy plane is set, and the contact surface in the second joint that matches the first contact surface is recorded as the second contact surface;

[0013] Under the condition that the center distance between the first constraint rope hole and the third constraint rope hole, the center distance between the second constraint rope hole and the fourth constraint rope hole, and the center distance between the fourth constraint rope hole and the fourth constraint rope hole remain unchanged, the coordinates of the first constraint rope hole and the fourth constraint rope hole in the established geometric model are changed to simulate the rotational movement between the first joint and the second joint. The outer contour of the first contact surface at different coordinates will form an envelope line, and an approximate curve is obtained by taking points on the envelope line as the projection curve of the second contact surface on the xy plane.

[0014] In some embodiments, outer surfaces of the first side wall and the third side wall are both planes, outer surfaces of the second side wall and the fourth side wall are both arc surfaces, and both ends of the second side wall and the fourth side wall are designed to be inclined surfaces.

[0015] In some embodiments, the drive member is a drive rope.

[0016] In some embodiments, the driving member adopts a ventilation hose, the driving member hole is a hose channel, and an elastic metal wire is provided between the ventilation hose and the side wall of the hose channel. After the ventilation hose is ventilated and expanded, the elastic metal wire is squeezed to increase the friction between the elastic metal wire and the joint.

[0017] In some embodiments, the driving member adopts a driving rope and a ventilation hose, and the driving member hole is divided into a driving rope hole and a hose channel. An elastic metal wire is provided between the ventilation hose and the side wall of the hose channel. After the ventilation hose is ventilated and expanded, the elastic metal wire is squeezed to increase the friction between the elastic metal wire and the joint.

[0018] A flexible mechanical arm joint provided by the embodiment of the present disclosure has the following characteristics and beneficial effects:

[0019] A new flexible robotic arm joint is designed in the present invention, which uses a cross-rope constraint connection and a step constraint design to improve the shear and torsion resistance of the flexible arm, which is of great significance for achieving precise control of the flexible arm. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the overall structure of a flexible robotic arm formed by joints provided by an embodiment of the present disclosure;

[0021] Figure 2 yes Figure 1 An axonometric view of a single joint in the flexible robotic arm shown;

[0022] Figure 3 Yes Figure 2 The schematic diagram of the joint shown after 180° flipping;

[0023] Figure 4 yes Figure 2 Side view of the joint shown;

[0024] Figure 5a and Figure 5b Yes Figure 2 Schematic diagram of the process of curve design for the first outer contact surface and the second outer contact surface in the joint shown.

[0025] Description of labels:

[0026] 100-flexible robotic arm; 110-joint; 111-first side wall; 112-second side wall; 113-third side wall; 114-fourth side wall; 121-first restraint rope; 122-second restraint rope; 131-first drive rope; 132-second drive rope; 141-first ventilation hose; 142-second ventilation hose; a1-first inner contact surface; a2-second inner contact surface; b1-first outer contact surface; b2-second outer contact surface; c1-first restraint rope hole; c2-second restraint rope hole; c3-third restraint rope hole; c4-fourth restraint rope hole; d1-first drive rope hole; d2-second drive rope hole; e1-first hose channel; e2-second hose channel; f-groove; 110A-front end joint; 110B-end joint; 110B1-end cover. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0028] On the contrary, the present application covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present application as defined by the claims. Further, in order to make the public have a better understanding of the present application, some specific details are described in detail in the detailed description of the present application below. Those skilled in the art can fully understand the present application without the description of these details.

[0029] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions that can be implemented in this application, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that can be produced by this application and the purposes that can be achieved, should still fall within the scope of the technical content disclosed in this application. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of narration, and are not used to limit the scope of the implementation of this application. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of this application without substantial change in the technical content.

[0030] See also Figure 1 , is a flexible robotic arm 100 formed by sequentially arranging the joints 110 provided by an embodiment of the present disclosure, and the flexible robotic arm 100 has one bending degree of freedom.

[0031] See also Figure 2~Figure 4, is a schematic diagram of the structure of a single joint 110 constituting a flexible robotic arm provided in an embodiment of the present disclosure. The joint 110 has a first side wall 111 and a third side wall 113 that are arranged opposite to each other, and a second side wall 112 and a fourth side wall 114 that are arranged opposite to each other. The ends of the first side wall 111 and the third side wall 113 serve as rolling contact surfaces of adjacent joints 110. The rolling contact surface is a stepped inner and outer contact curved surface, which is used to prevent torsion between the two joints 110. The inner contact curved surface located at one end of the same side wall protrudes from the outer contact curved surface, and the outer contact curved surface located at the other end of the side wall protrudes from the inner contact curved surface. A driving member hole for driving the flexible robotic arm 100 is respectively provided on the second side wall 112 and the fourth side wall 114; a restraint rope is connected between adjacent joints 110, and the restraint rope is arranged in a cross shape on the outside of the first side wall 111 and the third side wall 113, and the rope length of the restraint rope is unchanged and cannot be stretched, which is used to ensure close contact between adjacent joints 110, thereby improving the continuity of the flexible robotic arm when bending.

[0032] In some embodiments, a single joint 110 is a hollow block in a cylindrical shape formed by a first side wall 111, a second side wall 112, a third side wall 113 and a fourth side wall 114, and the hollow part is rectangular, which can reduce the weight of the joint 110. Figure 2 ( Figure 2 For the general Figure 1 ), from its side view, the joint 110 is symmetrical front and back, the first side wall 111 and the third side wall 113 are arranged oppositely and have the same structure, and the second side wall 112 and the fourth side wall 114 are arranged oppositely and have the same structure. The contact surface between the hollow part and each side wall serves as the inner surface of the corresponding side wall, the outer surfaces of the first side wall 111 and the third side wall 113 are both planes, and the outer surfaces of the second side wall 112 and the fourth side wall 114 are both arc surfaces.

[0033] The two ends of the first side wall 111 and the third side wall 113 serve as rolling contact surfaces between adjacent joints. Each rolling contact surface is a stepped inner and outer contact curved surface. Specifically, the rolling contact surface is located at one end of the first side wall 111 ( Figure 2 The rolling contact surface of the first side wall 111 (shown as the upper end) is composed of a first inner contact curved surface a1 and a first outer contact curved surface b1, and the first inner contact curved surface a1 protrudes from the first outer contact curved surface b1 and is located at the other end ( Figure 2The rolling contact surface of the third side wall 113 (shown as the lower end) is composed of a second inner contact curved surface a2 and a second outer contact curved surface b2, and the second outer contact curved surface b2 protrudes from the second inner contact curved surface a2. Since the third side wall 113 has the same structure as the first side wall 111 and is symmetrically arranged, the rolling contact surfaces at both ends of the third side wall 113 are the same as the rolling contact surfaces at both ends of the first side wall 111, and are not described here. Figure 1 and Figure 2 When the two joints 110 are in contact, the first inner contact surface a1 and the first outer contact surface b1 are in contact and tangent with the second inner contact surface a2 and the second outer contact surface b2 of the other joint, respectively. The two layers are in step-like contact to prevent the two joints 110 from twisting. Furthermore, the dimensions of the inner contact surface and the outer contact surface at one end of the same side wall along the thickness direction of the side wall (the dimension is defined as the width of the contact surface) are not equal, see Figure 4 , the width of the first inner contact surface a1 at the upper end of the first side wall 111 is smaller than the width of the first outer contact surface b1 at the upper end of the first side wall 111, and correspondingly, the width of the second inner contact surface a2 at the lower end of the first side wall 111 is larger than the width of the second outer contact surface b2 at the lower end of the first side wall 111, so that when the two joints 110 cooperate, there is a small gap between the side of the first inner contact surface a1 and the side of the second outer contact surface b2, thereby reducing the internal friction of the flexible robotic arm 100 when it bends. Similarly, the width of the first inner contact surface a1 at the upper end of the first side wall 111 can be set to be larger than the width of the first outer contact surface b1 at the upper end of the first side wall 111, and the width of the second inner contact surface a2 at the lower end of the first side wall 111 can be set to be smaller than the width of the second outer contact surface b2 at the lower end of the first side wall 111, and the above-mentioned effect can also be achieved.

[0034] refer to Figure 1 , Figure 2A first constraint rope hole c1, a second constraint rope hole c2, a third constraint rope hole c3 and a fourth constraint rope hole c4 are respectively formed on the first side wall 111 and the third side wall 113 of each joint 110 along the spacing direction of the first side wall 111 and the third side wall 113, and the four constraint rope holes are all through holes, that is, the two ends of the four constraint rope holes are respectively located on the first side wall 111 and the third side wall 113, and the center points of the four constraint rope holes are connected in sequence to form a rectangle, and the center point connecting line of the first constraint rope hole c1 and the third constraint rope hole c3 and the center point connecting line of the second constraint rope hole c2 and the fourth constraint rope hole c4 are respectively used as the diagonals of the rectangle, and each constraint rope hole should avoid the driving member hole on the joint to avoid the influence of the constraint rope on the driving member passing through the joint 100. In a specific embodiment of the present application, the first constraint rope hole c1 and the second constraint rope hole c2 are arranged near the inner surface of the second side wall 112, and the third constraint rope hole c3 and the fourth constraint rope hole c4 are arranged near the inner surface of the fourth side wall 114. There are two constraint ropes in the flexible robotic arm 100. The first constraint rope hole c1 and the third constraint rope hole c3 are used to pass the first constraint rope 121, and the second constraint rope hole c2 and the fourth constraint rope hole c4 are used to pass the second constraint rope 122. Specifically, the first constraint rope 121 connects the first constraint rope hole c1 and the third constraint rope hole c3 of the adjacent joint, and the second constraint rope 122 connects the second constraint rope hole c2 and the fourth constraint rope hole c4 of the adjacent joint. The two constraint ropes are crossed on the outer surface of the joint 110, and the rope length of the constraint rope is fixed and cannot be stretched. In this embodiment, both constraint ropes are made of nylon. The following describes in detail the method of threading the constraint rope in the flexible robotic arm:

[0035] The front end of the first restraint rope 121 is fixed on the front joint 110A. After the end of the first restraint rope 121 passes through the first restraint rope hole c1 on the first side wall 111 of the front joint 110A, it passes through the third restraint rope hole c3 on the first side wall 111 of the adjacent first joint, thereby entering the first joint. After the end of the first restraint rope 121 passes through the third restraint rope hole c3 on the third side wall 113 of the first joint, it passes through the first restraint rope hole c1 on the third side wall 113 of the adjacent second joint, and passes out of the second joint through the first restraint rope hole c1 on the first side wall 111 of the second joint. Subsequently, the end of the first restraint rope 121 continues to pass through the third restraint rope hole c3 and the first restraint rope hole c1 of the remaining joints in sequence in the above manner. Finally, the end of the first restraint rope 121 is fixed by the end joint 110B.

[0036] Similarly, the front end of the second restraint rope 122 is fixed on the front joint 110A, and the end of the second restraint rope 122 passes through the fourth restraint rope hole c4 on the first side wall 111 of the front joint 110A, and then passes through the second restraint rope hole c2 on the first side wall 111 of the adjacent first joint, thereby entering the first joint, and the end of the second restraint rope 122 passes through the second restraint rope hole c2 on the third side wall 113 of the first joint, and then passes through the second joint through the fourth restraint rope hole c4 on the third side wall 113 of the adjacent second joint, and then passes through the second joint through the fourth restraint rope hole c4 on the first side wall 111 of the second joint, and then the end of the second restraint rope 122 continues to pass through the second restraint rope holes c2 and the fourth restraint rope holes c4 of the remaining joints in sequence according to the above method, and finally, the end of the second restraint rope 122 is fixed by the end joint 110B;

[0037] Thus, the first restraint rope 121 and the second restraint rope 122 are arranged in a cross shape on the outer surfaces of the first side wall 111 and the third side wall 113 of each joint, and are arranged in parallel inside each joint.

[0038] It should be noted that the present application is not limited to the above-mentioned rope threading method, as long as a cross shape can be formed on the outer wall of the joint 110. In addition, the number of restraint ropes in the flexible robotic arm 100 can also be 1 or 4. When 1 restraint rope is used, the restraint rope in the joint at the end (which can be the front joint 110A or the end joint 110B) needs to be passed from the first side wall 111 through the inside of the joint to the third side wall 113; when 4 restraint ropes are used, the restraint ropes of the first side wall 111 and the third side wall 113 do not need to be passed through, that is, 2 restraint ropes are set on the outside of the first side wall 111, and another 2 restraint ropes are set on the outside of the third side wall 113.

[0039] Furthermore, in order to reduce the friction between the first restraint rope 121 and the second restraint rope 122 and improve the service life of the restraint rope, a second boss and a fourth boss protruding from their respective side walls and having the same structure are respectively provided at the second restraint rope hole c2 and the fourth restraint rope hole c4 on the first side wall 111 and the third side wall 113 of the joint 110, so that in the direction perpendicular to the plane where the first side wall 111 or the third side wall 113 is located, the positions of the second restraint rope hole c2 and the fourth restraint rope hole c4 are higher than the positions of the first restraint rope hole c1 and the third restraint rope hole c3, thereby avoiding contact between the first restraint rope 121 and the second restraint rope 122 at the intersection.

[0040] The restraint rope can strengthen the connection between two adjacent joints 110 and improve the continuity of the flexible manipulator 100 when bending. In order to ensure that two adjacent joints 110 can bend normally, the curve parameters of the first inner contact surface a1, the first outer contact surface b1, the second inner contact surface a2 and the second outer contact surface b2 at both ends of the joint 110 need to be calculated and designed. The following objectives are ultimately achieved: when the flexible manipulator 100 bends, the rope length of the restraint rope remains unchanged, the first inner contact surface a1 and the first outer contact surface b1 always maintain contact with the second inner contact surface a2 and the second outer contact surface b2 of the adjacent joints, respectively, thereby improving the continuity and stability of the movement of the flexible manipulator 100.

[0041] The curve design of each inner and outer contact surface is now described. First, the first outer contact surface b1 and the second outer contact surface b2 are taken as examples. The first inner contact surface a1 and the second inner contact surface a2 can be obtained in the same way. Figure 3 , Figure 5a and Figure 5b , points A, B, C, and D correspond to the third constraint rope hole c3, the second constraint rope hole c2, the first constraint rope hole c1, and the fourth constraint rope hole c4 respectively. Point F is the intersection of line segments AC and BD. Curve c is a circle with point A as the center and line segment AC as the radius. Curve d is a circle with point B as the center and line segment BD as the radius. The dotted line l is the perpendicular line of line segment CD. Take the center of the third constraint rope hole c3 ( Figure 5a , Figure 5b Point A in the middle) is the coordinate origin, with the third constraint rope hole c3 and the second constraint rope hole c2 ( Figure 5a , Figure 5b The straight line where the center line of point B in the middle is located is the x-axis, and the straight line parallel to the axial direction of the flexible robot arm 100 is the y-axis, and connected to the first constraint rope hole c1 ( Figure 5a , Figure 5b Point C) and the fourth constraint rope hole c4 ( Figure 5a , Figure 5b The projection of the first outer contact surface b1 on the xy plane is set to be an elliptical curve (see Figure 5a , Figure 5b The elliptic curve determined by points C, D, and E in the elliptic curve, wherein points C and D are two foci of the elliptic curve, and point E is any point on the elliptic curve. It should be noted that the first outer contact surface b1 can also be set to other surface forms) is local, and its geometric relationship with the fourth constraint rope hole c4 and the first constraint rope hole c1 remains fixed. Under the condition that the lengths of the first constraint rope 121 and the second constraint rope 122 remain unchanged, the coordinates of the first constraint rope hole c1 and the fourth constraint rope hole c4 in the established geometric model are changed (i.e. Figure 5a , Figure 5bThe lengths of the midline segments AC, BD, and CD remain unchanged, and the angle between segment AC and segment AB is changed to simulate the rotational motion between joints. The outer contour of the first outer contact surface b1 at different coordinates will form an envelope, and points are taken on this envelope (i.e. Figure 5a , Figure 5b H point in the figure) to obtain an approximate curve as the projection curve of the second outer contact surface b2 on the xy plane.

[0042] refer to Figure 1~Figure 4 The driving member of the flexible robot arm 100 of the embodiment of the present disclosure adopts a hybrid control method of rope drive and air drive. Therefore, the driving member hole set in each joint 110 is composed of a plurality of hose channels and driving rope holes symmetrically formed inside the second side wall 112 and the fourth side wall 114 and arranged along the axis direction of the flexible robot arm 100. The end of each driving rope is fixed on the end joint 110B. In a specific embodiment of the present application, a total of four silicone hoses are provided as ventilation hoses, namely two first ventilation hoses 141 and two second ventilation hoses 142, and two steel wire ropes are provided as driving ropes, namely the first driving rope 131 and the second driving rope 132. Therefore, two first hose channels e1 and a first driving rope hole d1 located therebetween are provided on the second side wall 112, and two second hose channels e2 and a second driving rope hole d2 located therebetween are provided on the fourth side wall 114. Each first hose channel e1 is respectively provided for a first ventilation hose 141 to pass through, each second hose channel e2 is respectively provided for a second ventilation hose 142 to pass through, and the first driving rope hole d1 and the second driving rope hole d2 are respectively used for the first driving rope 131 and the second driving rope 132 to pass through. Two grooves f are provided on the side wall of each hose channel for placing elastic metal wires. The elastic metal wires can be made of nickel-titanium alloy wires. When the ventilation hose is ventilated and expanded, the elastic metal wires are squeezed to increase the friction between the elastic metal wires and the joint 110, thereby increasing the overall rigidity of the flexible robotic arm. It should be noted that the second side wall 112 and the fourth side wall 114 have two ends ( Figure 2 The spacing between the upper and lower ends (shown in the figure) gradually decreases from the inner surface to the outer surface of each side wall, that is, both ends of the second side wall 112 and the fourth side wall 114 are designed as inclined surfaces, and the rotation angle between two adjacent joints can be controlled by the inclination angle of the inclined surface.

[0043] refer to Figure 1The difference between the front joint 110A and the terminal joint 110B in the flexible robotic arm 100 and the middle joint 110 is that the front joint 110A and the terminal joint 110B are half of a single joint 110, that is, the front joint 110A and the terminal joint 110B are only provided with inner and outer double-layer contact surfaces at the end facing the joint 110 connected thereto, and the front joint 110A is fixed to a base (the base is not shown in the figure) at the end facing away from the joint 110 connected thereto, and the terminal joint 110B is connected to an end cover 110B1 at the end facing away from the joint 110 connected thereto, and the ventilation hose is sealed by the end cover 110B1 and the end of the drive rope is fixed.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0045] Although examples of the present invention have been shown and described above, it is to be understood that the above examples are illustrative and are not to be construed as limitations of the present invention, and that a person skilled in the art may make changes, modifications, substitutions and variations to the above examples within the scope of the present invention.

Claims

1. A flexible robotic arm joint, characterized in that: The joint has a first side wall and a third side wall that are arranged opposite to each other, and a second side wall and a fourth side wall that are arranged opposite to each other. The ends of the first side wall and the third side wall serve as rolling contact surfaces of adjacent joints in the flexible robotic arm. The rolling contact surface is an inner and outer contact curved surface in a stepped shape, which is used to prevent torsion between the two joints. The inner contact curved surface at one end of the same side wall protrudes from the outer contact curved surface, and the outer contact curved surface at the other end of the side wall protrudes from the inner contact curved surface. The second side wall and the fourth side wall are respectively provided with driving member holes for the driving member of the flexible robotic arm to pass through. A restraining rope is connected between adjacent joints. The restraining rope is arranged in a cross shape on the outer sides of the first side wall and the third side wall, and the rope length of the restraining rope is unchanged and cannot be stretched, which is used to ensure close contact between adjacent joints, thereby improving the continuity of the flexible robotic arm when bending. The first side wall and the third side wall are respectively formed with four restraint rope holes arranged along the respective wall thickness directions, the first restraint rope hole and the third restraint rope hole are arranged diagonally, and the second restraint rope hole and the fourth restraint rope hole are arranged diagonally, and the restraint rope is connected between the first restraint rope hole and the third restraint rope hole of two adjacent joints, and between the second restraint rope hole and the fourth restraint rope hole; The shapes of the inner contact curved surface and the outer contact curved surface of the joint end are determined according to the following steps: The center of the third constraint rope hole in the first joint is taken as the coordinate origin, the straight line where the center line of the third constraint rope hole and the second constraint rope hole in the first joint is located is taken as the x-axis, and the line parallel to the axial direction of the flexible mechanical arm is taken as the y-axis, and a geometric relationship model is established with the first constraint rope hole and the fourth constraint rope hole in the second joint, and the contact surface close to the fourth constraint rope hole and the first constraint rope hole in the first joint is recorded as the first contact surface, and its projection curve on the xy plane is set, and the contact surface in the second joint that matches the first contact surface is recorded as the second contact surface; Under the condition that the center distance between the first constraint rope hole and the third constraint rope hole, the center distance between the second constraint rope hole and the fourth constraint rope hole, and the center distance between the fourth constraint rope hole and the fourth constraint rope hole remain unchanged, the coordinates of the first constraint rope hole and the fourth constraint rope hole in the established geometric model are changed to simulate the rotational movement between the first joint and the second joint. The outer contour of the first contact surface at different coordinates will form an envelope line, and an approximate curve is obtained by taking points on the envelope line as the projection curve of the second contact surface on the xy plane.

2. The flexible robotic arm joint according to claim 1, characterized in that: The number of the restraint ropes arranged in the flexible mechanical arm is 1, 2 or 4.

3. The flexible robotic arm joint according to claim 1, characterized in that: In the two mating joints, there is a small gap between the side surface of the inner contact curved surface and the side surface of the outer contact curved surface to reduce the internal friction of the flexible mechanical arm when it is bent.

4. The flexible robotic arm joint according to claim 1, characterized in that: A boss is provided at a pair of diagonally arranged restraining rope holes on the same side wall of the joint to avoid contact between the restraining ropes at the intersection.

5. The flexible robotic arm joint according to claim 1, characterized in that: The outer surfaces of the first side wall and the third side wall are both planes, the outer surfaces of the second side wall and the fourth side wall are both arc surfaces, and both ends of the second side wall and the fourth side wall are designed to be inclined surfaces.

6. The flexible robotic arm joint according to claim 1, characterized in that: The driving member adopts a driving rope.

7. The flexible mechanical arm joint according to claim 1, characterized in that: The driving member adopts a ventilation hose, the driving member hole is a hose channel, and an elastic metal wire is arranged between the ventilation hose and the side wall of the hose channel. After the ventilation hose is ventilated and expanded, the elastic metal wire is squeezed to increase the friction between the elastic metal wire and the joint.

8. The flexible mechanical arm joint according to claim 1, characterized in that: The driving member adopts a driving rope and a ventilation hose. The driving member hole is divided into two types: a driving rope hole and a hose channel. An elastic metal wire is provided between the ventilation hose and the side wall of the hose channel. The ventilation hose squeezes the elastic metal wire after being ventilated and expanded to increase the friction between the elastic metal wire and the joint.

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