A flexible manipulator with rope-driven and pneumatic hybrid control

Abstract

The present disclosure provides a flexible manipulator with rope drive and pneumatic hybrid control, comprising: a serpentine arm, including a plurality of serpentine joints arranged in sequence and a constraint rope, a driving rope and a ventilation hose arranged along the axial direction thereof; the serpentine joint has first and third side walls and second and fourth side walls arranged opposite to each other, the ends of the first and third side walls serve as rolling contact surfaces of adjacent serpentine joints, and are stepped inner and outer contact curved surfaces, a hose channel and a driving rope hole are respectively provided on the second and fourth side walls, the end of the driving rope is fixed on the end serpentine joint, and an elastic metal wire is provided between the ventilation hose and the side wall of the hose channel; the constraint rope is connected between adjacent serpentine joints, and is arranged in a cross shape on the outside of the first and third side walls, and its rope length is constant and cannot be stretched; a driving unit, including a rope control mechanism and a pneumatic control mechanism respectively connected to the front end of the driving rope and the ventilation hose. The flexible manipulator has good motion performance and a stable structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible arms, and in particular relates to a flexible mechanical arm with rope drive and pneumatic hybrid control. 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. Compared with rigid robotic arms, flexible robotic arms usually have lower load capacity. This limits its application in certain heavy-duty tasks. The design of flexible robotic arms often needs to take into account the issues of integration and miniaturization in order to better adapt to specific working environments, especially in medical and rescue situations that require delicate operations. Most of the current flexible arms are single rope-driven control, and there are certain problems with motion performance, stability and stiffness. 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, the embodiment of the present disclosure provides a flexible robotic arm with rope drive and pneumatic hybrid control, which has good motion performance and stable structure.

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

[0006] The present disclosure provides a rope-driven and pneumatic hybrid-controlled flexible mechanical arm, comprising a serpentine arm and a driving unit;

[0007] The serpentine arm comprises a serpentine arm body composed of a number of serpentine joints arranged in sequence, and a restraining rope, a driving rope and a ventilation hose arranged axially along the serpentine arm body; the serpentine joint has 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 serve as rolling contact surfaces of adjacent serpentine joints, the rolling contact surface is a stepped inner and outer contact curved surface, which is used to prevent torsion between the two serpentine 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, and the second side wall and the fourth side wall are respectively provided with The hose passage through which the ventilation hose passes and the driving rope hole through which the driving rope passes, the end of the driving rope is fixed to the end snake bone joint of the serpentine arm body, an elastic metal wire is provided between the ventilation hose and the side wall of the hose passage, and the ventilation hose squeezes the elastic metal wire after being ventilated and expanded to increase the friction between the elastic metal wire and the snake bone joint, thereby increasing the overall rigidity of the serpentine arm body; the restraint rope is connected between adjacent snake bone joints and is arranged in a cross shape on the outside of the first side wall and the third side wall, and the rope length of the restraint rope is unchanged and cannot be stretched, so as to ensure the close contact of adjacent snake bone joints, thereby improving the continuity of the serpentine arm body when bending;

[0008] The driving unit includes a rope control mechanism and a gas control mechanism installed on a frame; the front end serpentine joint of the serpentine arm body is installed on the frame; the rope control mechanism is connected to the front end of the driving rope, and is used to control the retraction and extension of the driving rope to change the posture of the serpentine arm body; the gas control mechanism is connected to the front end of the ventilation hose, and is used to keep the air pressure in the ventilation hose constant.

[0009] In some embodiments, the number of the restraint ropes provided in the serpentine arm is 1, 2 or 4.

[0010] In some embodiments, in two matching snake-bone joints, a small gap exists between the side surfaces of the inner contact curved surface and the side surfaces of the outer contact curved surface to reduce the internal friction when the snake-shaped arm is bent.

[0011] 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 of the serpentine bone joint, 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 serpentine bone joints, and between the second constraint rope hole and the fourth constraint rope hole.

[0012] In some embodiments, a boss is provided at a pair of diagonally arranged restraint rope holes on the same side wall of the snake bone joint to avoid contact between the restraint ropes at the intersection.

[0013] In some embodiments, the shapes of the inner contact curved surface and the outer contact curved surface of the snake bone joint end are determined according to the following steps:

[0014] The center of the third constraint rope hole in the first serpentine 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 serpentine joint is located is taken as the x-axis, and the line parallel to the axial direction of the serpentine 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 serpentine joint, and the contact surface in the first serpentine joint close to the fourth constraint rope hole and the first constraint rope hole is recorded as the first contact surface, and its projection curve on the xy plane is set, and the contact surface in the second serpentine joint that matches the first contact surface is recorded as the second contact surface;

[0015] 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 serpentine joint and the second serpentine 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.

[0016] In some embodiments, the outer surfaces of the first side wall and the third side wall of the snake bone joint 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.

[0017] In some embodiments, the rope control mechanism includes at least one rope control assembly for controlling a corresponding one of the drive ropes;

[0018] The rope control assembly includes a motor, a lead screw, a slide, a tension sensor and a fixed pulley group; the output end of the motor is connected to the lead screw, the slide is movably mounted on the lead screw, and the retraction and extension of the drive rope are controlled by the movement of the slide. The tension sensor is fixed on the slide and connected to the drive rope for obtaining the tension of the drive rope in real time; the fixed pulley group is arranged between the slide and the front end of the serpentine arm for guiding the drive rope.

[0019] In some embodiments, the rope control assembly also includes a manual adjustment structure for manually adjusting the tightness of the drive rope, the manual adjustment structure includes a manual translation platform and a movable pulley, the movable pulley is fixed on a slider inside the manual translation platform, the drive rope passes around the movable pulley and then connects to the corresponding fixed pulley group, and the tightness of the drive rope is adjusted by the movable pulley as the slider moves.

[0020] In some embodiments, the air control mechanism includes an air source, a proportional valve, two solenoid valves and a plurality of air pipes; the air source is connected to the air inlet of the proportional valve through a main air pipe, and each solenoid valve is respectively arranged on a corresponding air pipe branch connected to the air outlet of the proportional valve, and the on and off of each air pipe branch is respectively controlled by the first solenoid valve and the second solenoid valve, and the air outlet of each air pipe branch is connected to the front end of the corresponding ventilation hose.

[0021] The flexible robot arm with rope drive and pneumatic hybrid control provided by the embodiment of the present disclosure has the following characteristics and beneficial effects:

[0022] The present invention designs a new snake-bone joint and uses a cross-rope constraint connection to improve the continuity and stability of the movement. Specifically, the snake-bone joint designed in the present invention is a rolling contact joint, and the rolling contact surface satisfies the condition of equal length and invariance of the cross-rope constraint of the movement. The present invention adopts a control method combining rope drive and pneumatics to improve the flexibility of the movement. At the same time, the addition of pneumatic control can increase the overall rigidity and stability. In the drive unit, a structure for manually adjusting the tightness of the wire rope is added to ensure the stability of the rope drive and improve the movement performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the overall structure of the flexible mechanical arm provided by an embodiment of the present disclosure;

[0024] Figure 2 yes Figure 1 A schematic diagram of the internal structure of the snake-shaped arm in the flexible robotic arm;

[0025] Figure 3 yes Figure 2 Axonometric view of a single snake joint in the snake arm shown;

[0026] Figure 4 Yes Figure 3 The schematic diagram of the snake bone joint after being flipped 180° is shown;

[0027] Figure 5 yes Figure 3 Side view of the serpentine joint shown;

[0028] Figure 6a and Figure 6b Yes Figure 3A schematic diagram of the process of curve design of the first outer contact surface and the second outer contact surface in the snake bone joint shown;

[0029] Figure 7 yes Figure 1 A schematic diagram of the internal structure of a driving module in the flexible robotic arm shown;

[0030] Figure 8 Yes Figure 7 A partial exploded schematic diagram of the driving module after the frame is hidden;

[0031] Fig. 9 yes Figure 1 A schematic diagram of the structure of the connecting parts in the flexible robotic arm shown;

[0032] Fig.10 yes Figure 1 A schematic diagram of the connection of the driving rope in the flexible robotic arm shown;

[0033] Fig.11 yes Figure 1 Schematic diagram of the connection of the gas circuit in the flexible robotic arm shown.

[0034] Description of labels:

[0035] 100-snake arm; 110-snake bone 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 snake bone joint; 110B-end snake bone joint; 110B1-end cover;

[0036] 200-driving unit; 210-rope control mechanism; 211-motor; 212-screw; 213-slide; 214-tension sensor; 215-movable pulley; 216-base; 217-guide rail; 218-slider; 219-knob; f2-second fixed pulley; f3-third fixed pulley; f4-fourth fixed pulley; f5-fifth fixed pulley; 220-gas control mechanism; 221-proportional valve; 222a-first solenoid valve; 222b-second solenoid valve; 230-frame; 231-connecting piece; 231a-bolt hole; 231b-connecting groove; 231c-first air pipe through hole; 231d-second air pipe through hole; 231e-first drive rope hole; 231f-second drive rope hole. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] See also Figures 1 to 11 , a flexible robot arm with rope drive and pneumatic hybrid control provided by an embodiment of the present disclosure has one bending degree of freedom, and the flexible robot arm includes a snake arm 100 and a drive unit 200;

[0041] The serpentine arm 100 comprises a serpentine arm body composed of a plurality of serpentine joints 110 arranged in sequence, and a restraining rope, a driving rope and a ventilation hose arranged axially along the serpentine arm body; the serpentine joint 110 comprises a first side wall 111 and a third side wall 113 arranged opposite to each other, and a second side wall 112 and a fourth side wall 114 arranged opposite to each other, and the ends of the first side wall 111 and the third side wall 113 serve as rolling contact surfaces of adjacent serpentine joints 110, and the rolling contact surfaces are inner and outer contact curved surfaces in a stepped shape, which are used to prevent torsion between the two serpentine joints 110, and 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, and at the second side The wall 112 and the fourth side wall 114 are respectively provided with a hose channel for the ventilation hose to pass through and a driving rope hole for the driving rope to pass through. The end of the driving rope is fixed on the end snake bone joint 110B of the serpentine arm body. 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 snake bone joint 110, thereby increasing the overall rigidity of the serpentine arm body; the restraint rope is connected between adjacent snake bone joints 110 and is arranged in a cross shape on the outside of the first side wall 111 and the third side wall 113. The rope length of the restraint rope is unchanged and cannot be stretched, which is used to ensure the close contact of adjacent snake bone joints 110, thereby improving the continuity of the serpentine arm body when bending;

[0042] The driving unit 200 includes a rope control mechanism 210 and a gas control mechanism 220 installed on a frame 230; the front end serpentine joint 110A of the serpentine arm body is installed on the frame 230; the rope control mechanism 210 is connected to the front end of the driving rope, and is used to control the retraction and extension of the driving rope to change the posture of the serpentine arm body; the gas control mechanism 220 is connected to the front end of the ventilation hose, and is used to keep the air pressure in the ventilation hose constant.

[0043] In some embodiments, see Figure 3 , 4 5. The snake bone joint 110 is a key component of the flexible mechanical arm provided by the embodiment of the present disclosure. A single snake bone joint 110 is a hollow block in a cylindrical shape formed by the first side wall 111, the second side wall 112, the third side wall 113 and the fourth side wall 114. The hollow part is rectangular, which can reduce the weight of the snake bone joint 110. Figure 3 ( Figure 3 For the general Figure 2), from its side view, the snake bone 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.

[0044] The two ends of the first side wall 111 and the third side wall 113 serve as rolling contact surfaces between adjacent snake bone joints. Each rolling contact surface is a stepped inner and outer contact curved surface. Specifically, the first side wall 111 is located at one end ( Figure 3 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 3 The 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 2 and Figure 3 When two snake-bone joints 110 are in contact, their first inner contact surface a1 and first outer contact surface b1 are in contact and tangent with the second inner contact surface a2 and second outer contact surface b2 of the other snake-bone joint, respectively. The two layers are in step-like contact to prevent the two snake-bone 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 5, 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 serpentine 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 when the serpentine arm 100 is bent. 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.

[0045] refer to Figure 2 , Figure 3 A 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 snake bone 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 connection line of the first constraint rope hole c1 and the third constraint rope hole c3 and the center point connection 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 rope hole and the hose channel setting in the snake bone joint 110 to avoid the influence of the constraint rope on the driving rope and the ventilation hose passing through the snake bone joint. 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 serpentine 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 serpentine joint, and the second constraint rope 122 connects the second constraint rope hole c2 and the fourth constraint rope hole c4 of the adjacent serpentine joint. The two constraint ropes are crossed on the outer surface of the serpentine 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 serpentine arm body:

[0046] The front end of the first restraint rope 121 is fixed on the front serpentine joint 110A. 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 serpentine joint 110A, and then passes through the third restraint rope hole c3 on the first side wall 111 of the adjacent first serpentine joint, thereby entering the first serpentine joint. 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 serpentine joint, and then passes through the second serpentine joint through the first restraint rope hole c1 on the first side wall 111 of the second serpentine 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 serpentine joints in sequence in the above manner. Finally, the end of the first restraint rope 121 is fixed by the end serpentine joint 110B.

[0047] Similarly, the front end of the second restraint rope 122 is fixed on the front serpentine 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 serpentine joint 110A, and then passes through the second restraint rope hole c2 on the first side wall 111 of the adjacent first serpentine joint, thereby entering the first serpentine 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 serpentine joint, and then passes through the second serpentine joint through the fourth restraint rope hole c4 on the third side wall 113 of the adjacent second serpentine joint, and then passes through the second serpentine joint through the fourth restraint rope hole c4 on the first side wall 111 of the second serpentine 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 serpentine joints in sequence according to the above method, and finally, the end of the second restraint rope 122 is fixed by the end serpentine joint 110B;

[0048] 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 snake bone joint, and are arranged in parallel inside each snake bone joint.

[0049] 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 snake bone joint 110. In addition, the number of restraint ropes in the serpentine arm 100 can also be 1 or 4. When 1 restraint rope is used, the restraint rope in the snake bone joint at the end (which can be the front snake bone joint 110A or the terminal snake bone joint 110B) needs to be passed from the first side wall 111 through the inside of the snake bone 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.

[0050] 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 serpentine 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.

[0051] The restraint rope can strengthen the connection between two adjacent serpentine joints 110 and improve the continuity of the serpentine arm 100 when it is bent. In order to ensure that two adjacent serpentine 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 serpentine joint 110 need to be calculated and designed. The following objectives are ultimately achieved: when the serpentine arm 100 is bent, 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 serpentine joints, respectively, and the continuity and stability of the movement of the serpentine arm 100 are improved.

[0052] 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 4 , Figure 6a and Figure 6b , 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 6a , Figure 6b Point A in the middle) is the coordinate origin, with the third constraint rope hole c3 and the second constraint rope hole c2 ( Figure 6a , Figure 6b 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 snake arm 100 is the y-axis, and connected to the first constraint rope hole c1 ( Figure 6a , Figure 6b Point C) and the fourth constraint rope hole c4 ( Figure 6a , Figure 6bThe projection of the first outer contact surface b1 on the xy plane is set to be an elliptical curve (see Figure 6a , Figure 6b 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 6a , Figure 6b The 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 the snake 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 6a , Figure 6b 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.

[0053] refer to Figure 2~Figure 5 A plurality of hose channels and drive rope holes are symmetrically formed inside the second side wall 112 and the fourth side wall 114 of the snake-bone joint 110 and are arranged along the axis direction of the snake-shaped arm 100. 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 drive ropes, namely the first drive rope 131 and the second drive rope 132. Therefore, two first hose channels e1 and a first drive rope hole d1 located therebetween are provided on the second side wall 112, and two second hose channels e2 and a second drive rope hole d2 located therebetween are provided on the fourth side wall 114. Each first hose channel e1 is provided for a first ventilation hose 141 to pass through, and each second hose channel e2 is provided for a second ventilation hose 142 to pass through. The first drive rope hole d1 and the second drive rope hole d2 are provided for the first drive rope 131 and the second drive rope 132 to pass through, respectively. Two grooves f are provided on the side wall of each hose channel for placing elastic metal wires, and the elastic metal wires can be made of nickel-titanium alloy wires. It should be noted that the second side wall 112 and the fourth side wall 114 have two ends ( Figure 3 The spacing between the second side wall 112 and the fourth side wall 114 (shown as the upper and lower ends) 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 snake bone joints can be controlled by the inclination angle of the inclined surface.

[0054] refer to Figure 2The difference between the front end serpentine joint 110A and the terminal serpentine joint 110B in the serpentine arm 100 and the middle serpentine joint 110 is that the front end serpentine joint 110A and the terminal serpentine joint 110B are half of a single serpentine joint 110, that is, the front end serpentine joint 110A and the terminal serpentine joint 110B are only provided with inner and outer double-layer contact surfaces at one end facing the serpentine joint 110 connected thereto, the front end serpentine joint 110A is fixedly connected to the frame 230 of the drive unit 200 at one end facing away from the serpentine joint 110 connected thereto, and the terminal serpentine joint 110B is connected to an end cover 110B1 at one end facing away from the serpentine joint 110 connected thereto, and the ventilation hose is sealed by the end cover 110B1 and the end of the drive rope is fixed.

[0055] refer to Figure 7~Figure 11 The driving unit 200 in the flexible robotic arm provided in this embodiment mainly realizes the functions of driving rope retraction and pneumatic control. The driving unit 200 includes a rope control mechanism 210 and a pneumatic control mechanism 220 installed on a frame 230.

[0056] The frame 230 is a box-shaped structure with two layers, one above the other. A connector 231 for mounting the front serpentine joint 110A is provided on the side wall of the frame 230 facing the front end of the serpentine arm 100, and each ventilation hose and driving rope in the serpentine arm 100 passes through the side wall of the frame 230 and the connector 231. Fig. 9 The connecting member 231 is provided with two bolt holes 231a, four air pipe through holes, two drive rope holes and a connecting groove 231b. The connecting member 231 is fixed to the front side wall of the frame 230 by bolt connection through the two bolt holes 231a. The connecting groove 231b on the connecting member 231 is snap-fitted with the front end serpentine joint 110A in the serpentine arm 100, so that the serpentine arm 100 and the drive unit 200 are connected together. The four air pipe through holes on the connecting member 231 are arranged at the four corners of the connecting groove 231b. The two first air pipe through holes 231c located on the upper side of the connecting groove 231b are respectively used to pass a corresponding first ventilation hose 141, and the two second air pipe through holes 231d located on the lower side of the connecting groove 231b are respectively used to pass a corresponding second ventilation hose 142. The first drive rope hole 231e is located between the two first air pipe through holes 231c, and is used for the first drive rope 131 to pass through; the second drive rope hole 231f is located between the two second air pipe through holes 231d, and is used for the second drive rope 132 to pass through.

[0057] refer to Figure 7 , Figure 8The rope control mechanism 210 includes a first rope control assembly and a second rope control assembly which are arranged vertically in the frame 230, and are used to control the first driving rope 131 and the second driving rope 132 respectively. Each rope control assembly includes a motor 211, a lead screw 212, a slide 213, a tension sensor 214 and a fixed pulley block. The output end of the motor 211 is connected to the lead screw 212 to drive the lead screw 212 to rotate. The slide 213 is sleeved on the lead screw 212. When the lead screw 212 rotates, the slide 213 can reciprocate along the axial direction of the lead screw 212. The movement of the slide 213 can control the tension and relaxation of the corresponding driving rope, thereby controlling the bending movement of the serpentine arm 100. The tension sensor 214 is fixed on the slide 213 and connected to a corresponding driving rope, and is used to obtain the tension of the corresponding driving rope in real time.

[0058] The fixed pulley block is arranged between the slide 213 and the front end of the serpentine arm 100, and is used to guide the driving rope. It should be noted that the difference between the first rope control assembly and the second rope control assembly is reflected in the arrangement of the fixed pulleys therein. Since the first rope control assembly and the second rope control assembly are arranged in the frame 230 in the form of upper and lower layers, the fixed pulley block in the second rope control assembly (hereinafter referred to as the second fixed pulley block) has two more fixed pulleys for changing the vertical height of the driving rope than the fixed pulley block in the first rope control assembly (hereinafter referred to as the first fixed pulley block). Specifically, see Fig.10 The first fixed pulley group is composed of a second fixed pulley f2 and a third fixed pulley f3 which are arranged in sequence. The axial directions of the two fixed pulleys are arranged in the vertical direction and are fixedly connected to the frame 230. The front end of the first driving rope 131 passes through the front side wall of the frame 230 at the first driving rope hole 231e on the connecting member 231 and then passes through the second fixed pulley f2 and the third fixed pulley f3 in the first fixed pulley group in sequence to change the horizontal position of the first driving rope 131, and then is connected to the tension sensor 214 in the first rope control assembly. On the basis of the first fixed pulley group, the second fixed pulley group is additionally provided with a fourth fixed pulley f4 and a fifth fixed pulley f5 between the connecting member 231 and the second fixed pulley f2, and the axial directions of the fourth fixed pulley f4 and the fifth fixed pulley f5 are arranged horizontally, so as to change the vertical position of the second driving rope 132. The front end of the second driving rope 132 passes through the front side wall of the frame 230 of the second driving rope hole 231f on the connecting piece 231, and then passes through the fourth fixed pulley f4 and the fifth fixed pulley f5 in the second fixed pulley group in sequence to change the vertical position of the second driving rope 132, and then passes through the second fixed pulley f2 and the third fixed pulley f3 in the second fixed pulley group in sequence to change the horizontal position of the second driving rope 132, and then is connected to the tension sensor 214 in the second rope control assembly.

[0059] Furthermore, each group of rope control components also includes a manual adjustment structure, each manual adjustment structure is located on the side of the lead screw 212 away from the front end of the serpentine arm 100, and is used to manually adjust the tightness of the corresponding driving rope. The manual adjustment structure includes a manual translation platform and a movable pulley 215 arranged axially in the vertical direction. The manual translation platform includes a base 216, a guide rail 217, a slider 218 and a knob 219. The base 216 is fixedly connected to the frame 230, one end of the guide rail 217 is rotatably connected to the base 216 through a bearing, and the other end of the guide rail 217 is fixedly connected to the knob 219 after passing through the side wall of the base 216. The slider 218 is sleeved on the guide rail 217 and threadedly matched with the guide rail 217. The movable pulley 215 is fixed on the slider 218, and a corresponding driving rope passes around the movable pulley 215 and then connects to the corresponding fixed pulley group. The guide rail 217 is driven to rotate by manually turning the knob 219, so that the slider 218 and the movable pulley 215 thereon can be reciprocated along the axial direction of the guide rail 217. The movement of the movable pulley 215 will tighten or loosen the drive rope, thereby realizing the function of manually adjusting the tightness of the drive rope. When the tightness of the drive rope does not need to be adjusted, the movable pulley 215 remains stationary. The manual adjustment method can avoid the situation that the adjustment cannot be made due to the limited travel of the slide 213, and on the other hand, the manual adjustment can adjust the tightness of the drive rope without power.

[0060] The gas control mechanism 220 includes a gas source (the gas source is Figure 7 , Figure 8 The first solenoid valve 222a and the second solenoid valve 222b are both two-position two-way solenoid valves, which are respectively arranged on two air pipe branches. Each air pipe branch is respectively connected to an air outlet of the proportional valve 221, and the first solenoid valve 222a and the second solenoid valve 222b are respectively controlled to be on and off each air pipe branch. Specifically, see Fig.11, is a schematic diagram of gas circuit connection, the main gas pipe connected to the gas source first passes through the proportional valve 221 to adjust the gas pressure; after passing through the proportional valve 221, the main gas circuit is divided into two primary branches and passes through the first solenoid valve 222a and the second solenoid valve 222b respectively, each primary branch is further divided into two secondary branches, a total of four gas circuits, of which two secondary branches are connected to a corresponding first ventilation hose 141 through the two first air pipe through holes 231c on the connecting piece 231, and the remaining two secondary branches are connected to a corresponding second ventilation hose 142 through the two second air pipe through holes 231d on the connecting piece 231. When the serpentine arm 100 needs stronger rigidity and stability, the proportional valve 221 and the first solenoid valve 222a and the second solenoid valve 222b can be controlled to expand the corresponding ventilation hose and squeeze the elastic metal wire, increase the friction between the elastic metal wire and each snake bone joint, and thus meet the requirements of improving the rigidity and stability of the serpentine arm 100.

[0061] 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.

[0062] 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 manipulator with rope drive and pneumatic hybrid control, characterized in that: Including a serpentine arm and a drive unit; The serpentine arm comprises a serpentine arm body composed of a number of serpentine joints arranged in sequence, and a restraining rope, a driving rope and a ventilation hose arranged axially along the serpentine arm body; the serpentine joint has 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 serve as rolling contact surfaces of adjacent serpentine joints, the rolling contact surface is a stepped inner and outer contact curved surface, which is used to prevent torsion between the two serpentine 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, and the second side wall and the fourth side wall are respectively provided with The hose passage through which the ventilation hose passes and the driving rope hole through which the driving rope passes, the end of the driving rope is fixed to the end snake bone joint of the serpentine arm body, an elastic metal wire is provided between the ventilation hose and the side wall of the hose passage, and the ventilation hose squeezes the elastic metal wire after being ventilated and expanded to increase the friction between the elastic metal wire and the snake bone joint, thereby increasing the overall rigidity of the serpentine arm body; the restraint rope is connected between adjacent snake bone joints and is arranged in a cross shape on the outside of the first side wall and the third side wall, and the rope length of the restraint rope is unchanged and cannot be stretched, so as to ensure the close contact of adjacent snake bone joints, thereby improving the continuity of the serpentine arm body when bending; The driving unit includes a rope control mechanism and a gas control mechanism installed on a frame; the front end serpentine joint of the serpentine arm body is installed on the frame; the rope control mechanism is connected to the front end of the driving rope, and is used to control the retraction and extension of the driving rope to change the posture of the serpentine arm body; the gas control mechanism is connected to the front end of the ventilation hose, and is used to keep the air pressure in the ventilation hose constant.

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

3. The flexible robotic arm according to claim 1, characterized in that: In the two matching snake-bone 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 when the snake-shaped arm is bent.

4. The flexible robotic arm according to claim 1, characterized in that: The first side wall and the third side wall of the snake bone joint are respectively formed with four constraint rope holes arranged along the direction of their respective wall thicknesses. 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. The constraint rope is connected between the first constraint rope hole and the third constraint rope hole of two adjacent snake bone joints, and between the second constraint rope hole and the fourth constraint rope hole.

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

6. The flexible robotic arm according to claim 4, characterized in that: The shapes of the inner contact curved surface and the outer contact curved surface of the end of the snake bone joint are determined according to the following steps: The center of the third constraint rope hole in the first serpentine 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 serpentine joint is located is taken as the x-axis, and the line parallel to the axial direction of the serpentine 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 serpentine joint, and the contact surface in the first serpentine joint close to the fourth constraint rope hole and the first constraint rope hole is recorded as the first contact surface, and its projection curve on the xy plane is set, and the contact surface in the second serpentine 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 serpentine joint and the second serpentine 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.

7. The flexible robotic arm according to claim 1, characterized in that: The outer surfaces of the first side wall and the third side wall of the snake bone joint 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 as inclined surfaces.

8. The flexible robotic arm according to claim 1, characterized in that: The rope control mechanism includes at least one rope control assembly for controlling a corresponding driving rope; The rope control assembly includes a motor, a lead screw, a slide, a tension sensor and a fixed pulley group; the output end of the motor is connected to the lead screw, the slide is movably mounted on the lead screw, and the retraction and extension of the drive rope are controlled by the movement of the slide. The tension sensor is fixed on the slide and connected to the drive rope for obtaining the tension of the drive rope in real time; the fixed pulley group is arranged between the slide and the front end of the serpentine arm for guiding the drive rope.

9. The flexible robotic arm according to claim 8, characterized in that: The rope control assembly also includes a manual adjustment structure for manually adjusting the tightness of the drive rope, the manual adjustment structure includes a manual translation platform and a movable pulley, the movable pulley is fixed on a slider in the manual translation platform, the drive rope passes around the movable pulley and then connects to the corresponding fixed pulley group, and the tightness of the drive rope is adjusted by the movable pulley as the slider moves.

10. The flexible robotic arm according to claim 1, characterized in that: The air control mechanism includes an air source, a proportional valve, two solenoid valves and a plurality of air pipes; the air source is connected to the air inlet of the proportional valve through a main air pipe, and each solenoid valve is respectively arranged on a corresponding air pipe branch connected to the air outlet of the proportional valve, and the on and off of each air pipe branch is respectively controlled by the first solenoid valve and the second solenoid valve, and the air outlet of each air pipe branch is connected to the front end of the corresponding ventilation hose.

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