Rope-driven bending unit and snakelike mechanical arm

Abstract

The invention relates to the technical field of mechanical arms, and discloses a rope-driven bending unit and a snakelike mechanical arm. The bending unit comprises a supporting disc, a steering engine, a limiting disc and a plurality of bending assemblies, each bending assembly comprises two bending mechanisms, each bending mechanism comprises a hinged support and a connecting rod, one end of each connecting rod is rotationally connected with the corresponding hinged support, and the other end of each connecting rod is rotationally connected with the corresponding hinged support. The other ends of the two connecting rods are rotationally connected with each other, abutting parts are formed at the connecting positions, the number of the bending assemblies is three or an odd number of more than three, the bending assemblies are evenly distributed in the circumferential direction, the limiting disc is of a symmetrical crescent-shaped disc-shaped structure, the abutting parts are all matched with the periphery of the limiting disc, and the steering engine is used for driving the limiting disc to rotate. The snakelike mechanical arm comprises a plurality of bending units which are connected in sequence, and a mounting disc is arranged at the tail end of the snakelike mechanical arm to carry an execution end device. The rope-driven bending unit and the snakelike mechanical arm are light and simple in structure, enough rigidity can be kept in the bending posture, and high loads can be borne.

Description

Technical Field

[0001] The present invention relates to the technical field of robotic arms, and particularly to a cable-driven bending unit and a snake-shaped robotic arm. Background Art

[0002] In the maintenance operations in some narrow spaces (such as the regular maintenance of aerospace engines, aircraft fuel tanks, nuclear reactors, etc.), due to the small available working space and the relatively dangerous working environment, there are problems of high risk and great operation difficulty in the maintenance operations. To solve these problems, more and more robotic arms are used to replace humans to complete the maintenance work. Due to the limitations of its own structure and fewer degrees of freedom, the traditional rigid robotic arm is difficult to meet the requirements of entering narrow and complex spaces. The snake-shaped robotic arm has the characteristics of more degrees of freedom and higher flexibility. Therefore, for the above-mentioned maintenance operation environment in narrow and complex spaces, technicians have been committed to the research of snake-shaped robotic arms.

[0003] There are two common configurations of the existing snake-shaped robotic arms, namely the flexible central rod type and the universal joint type. Among them, the flexible central rod type robotic arm is supported by a central rod, and the discs on the rod are bent and controlled by pulling the drive cables, which has a high degree of freedom and a light weight, but has the disadvantage of insufficient rigidity and can carry a small load; the universal joint type robotic arm is connected by universal joints, and its flexibility depends on the number of universal joints and the angles at which the universal joints can rotate, which has a high degree of flexibility, stiffness and load capacity, but the structure of the robotic arm itself is relatively complex and the weight is heavier. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a cable-driven bending unit and a snake-shaped robotic arm, which have a simple and light structure and can maintain sufficient rigidity in the bending posture and can carry a higher load.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A cable-driven bending unit includes a support disk, a servo motor, a limit disk, and a plurality of bending components. The servo motor is fixedly installed on the support disk. The limit disk is fixedly connected to the output shaft of the servo motor. A plurality of the bending components are circumferentially distributed around the output shaft of the servo motor, and the number of the bending components is an odd number of three or more. Each bending component includes two bending mechanisms. Each bending mechanism includes a hinge support and a connecting rod. One ends of the two connecting rods are respectively rotatably connected to the two hinge supports, and the other ends of the two connecting rods are rotatably connected to each other. A contact portion is formed at the connecting position of the two connecting rods. One hinge support is fixedly connected to one end of the support disk, and the other hinge support is adapted to the other end of the support disk. The contact portion can bend along the radial direction of the output shaft of the servo motor towards the axis direction of the output shaft of the servo motor. The limit disk has a symmetric crescent-shaped disk structure. The symmetry axis of the limit disk is parallel to the radial direction of the output shaft of the servo motor. A plurality of the contact portions are all adapted to the outer periphery of the limit disk. When each bending component is bent by cable drive, each contact portion abuts against the outer periphery of the limit disk. Since the limit disk has a crescent-shaped structure, the bending angles of the bending components are different. At this time, the bending unit bends towards the inner side of the crescent shape of the limit disk. And because of the reaction force of the limit disk, the stiffness in the bent state can be maintained. The servo motor can drive the limit disk to rotate so as to adjust the bending direction of the bending unit.

[0007] Further, a limit pin is provided on the hinge support. The limit pin is used to limit the angle of the contact portion swinging away from the axis direction of the output shaft of the servo motor, so as to ensure that each bending component bends inward under cable drive.

[0008] Further, a torsion spring is further provided between the hinge support and the connecting rod in the bending mechanism. The torsion spring is used to provide an elastic force for the contact portion to swing away from the axis direction of the output shaft of the servo motor. When the cable tension of the cable drive is released in the bent state, the bending unit can be reset by this elastic force.

[0009] Specifically, the outer periphery of the limit disk includes an arc section and a concave section. The two ends of the arc section are respectively connected to the two ends of the concave section. The arc section is coaxial with the output shaft of the servo motor.

[0010] A cable-driven snake-shaped robotic arm includes a mounting disk and a plurality of the aforementioned cable-driven bending units. A plurality of the cable-driven bending units are connected in sequence. The hinge supports far from the limit disk in the previous cable-driven bending unit are all fixedly connected to the limit disks in the next cable-driven bending unit. The hinge supports far from the limit disk in the last cable-driven bending unit are all fixedly connected to the mounting disk.

[0011] Further, it further includes a plurality of driving mechanisms. The driving mechanism includes a driving motor, a wire reel, and a pulling rope. The driving motor is fixedly connected to the limiting disc in the rope-driven bending unit away from the mounting disc. The wire reel is fixedly sleeved on the output shaft of the driving motor. One end of the pulling rope is fixedly wound on the wire reel, and the other end of the pulling rope sequentially passes through a plurality of the limiting discs and then is fixedly connected to the mounting disc. The driving motor can drive the wire reel to rotate, so that one end of the pulling rope is gradually wound on the wire reel, and the other end of the pulling rope acts on the mounting disc to provide a pulling force. In each of the rope-driven bending units, a plurality of the pulling ropes are respectively arranged close to a plurality of the bending assemblies.

[0012] The beneficial effects of the present invention are as follows:

[0013] The rope-driven bending unit includes a support disc, a steering gear, a limiting disc, and a plurality of bending assemblies. The bending assembly includes two bending mechanisms. The bending mechanism includes a hinge support and a connecting rod. One ends of two connecting rods are respectively rotatably connected to two hinge supports, and the other ends of the two connecting rods are rotatably connected to each other. A contact portion is formed at the position where the two connecting rods are connected. The number of the bending assemblies is an odd number of three or more, and each bending assembly is arranged circumferentially and evenly. The above-mentioned limiting disc has a symmetric crescent-shaped disc structure. When each bending assembly is bent by rope driving, each contact portion abuts against the outer periphery of the limiting disc. Since the limiting disc has a crescent-shaped structure, the bending angles of each bending assembly are different. At this time, the bending unit bends towards the inner side of the crescent shape of the limiting disc, and due to the reaction force of the limiting disc, the structural stiffness in the bent state can be maintained. The steering gear can drive the limiting disc to rotate so as to adjust the bending direction of the bending unit.

[0014] The rope-driven snake-like robotic arm includes a mounting disc, a plurality of driving mechanisms, and a plurality of the foregoing rope-driven bending units. Each rope-driven bending unit is connected in sequence. The mounting disc is connected to the outermost end for mounting the end effector device. The driving mechanism corresponds to the number of bending assemblies in the bending unit. It includes a driving motor, a wire reel, and a pulling rope. One end of the pulling rope is fixed on the wire reel, and the other end of the pulling rope sequentially passes through each support disc and then is connected to the mounting disc. When the driving motor drives the wire reel to rotate, it can drive one end of the pulling rope to wind on the wire reel, and the other end of the pulling rope acts on the mounting disc to provide a rope-driven pulling force. Through the action of each driving mechanism, a rope-driven pulling force can be provided for each bending assembly in each bending unit. The overall structure of the rope-driven snake-like robotic arm is light and simple; the bending direction of each bending unit is respectively controlled by each steering gear, and the bending flexibility is relatively high; each bending unit can maintain a high stiffness in the bent state, so that the entire robotic arm can maintain sufficient rigidity in the bent state and can carry a relatively high load. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of a rope-driven snake-like robotic arm according to the present invention;

[0016] Figure 2 This is a schematic structural diagram of a rope-driven bending unit of the present invention;

[0017] Figure 3 This is a schematic structural diagram of a driving mechanism in a rope-driven snake-like robotic arm of the present invention;

[0018] Figure 4 This is a schematic structural diagram of a rope-driven snake-like robotic arm in a bent state of the present invention;

[0019] In the figure, 1 - support disk, 2 - servo motor, 3 - limit disk, 4 - connecting rod, 5 - hinge support, 6 - mounting disk, 7 - driving motor, 8 - wire reel, 9 - pulling rope. Detailed implementation manners

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0021] As Figure 2 shown, a rope-driven bending unit includes a support disk 1, a servo motor 2, a limit disk 3 and a plurality of bending assemblies. Each bending assembly includes two bending mechanisms. The bending mechanism includes a connecting rod 4 and a hinge support 5. One end of the connecting rod 4 is rotatably connected to the hinge support 5. The ends of the two connecting rods 4 away from the hinge support 5 are rotatably connected to each other. The rotation axis of the relative rotation of the two connecting rods 4 is parallel to the rotation axis of the connecting rod 4 relative to the hinge support 5. An abutting portion is formed at the position where the two connecting rods 4 are connected to each other. The servo motor 2 is fixedly installed on the support disk 1. The limit disk 3 is fixedly connected to the output shaft of the servo motor 2. The number of the above-mentioned bending assemblies is an odd number of three or more. These bending assemblies are circumferentially and evenly arranged around the output shaft of the servo motor 2. In each bending assembly, one hinge support 5 is fixedly connected to one end of the support disk 1, and the other hinge support 5 is adaptively and fixedly connectable to the other end of the support disk 1. Each abutting portion can be bent along the radial direction of the output shaft of the servo motor 2 towards the axis direction of the output shaft of the servo motor 2. The above-mentioned limit disk 3 has a symmetric crescent-shaped disk structure. The limit disk 3 is parallel to the support disk 1, and its symmetry axis is parallel to the radial direction of the output shaft of the servo motor 2. A plurality of abutting portions are all adapted to the outer circumference of the limit disk. When the abutting portion of the bending assembly bends towards the axis direction of the output shaft of the servo motor 2, it can abut against the outer circumference of the limit disk 3. Specifically, the fact that the limit disk 3 has a symmetric crescent-shaped disk structure means that the outer circumference of the limit disk 3 includes an arc segment and a concave segment. The two ends of the arc segment are respectively connected to the two ends of the concave segment. The arc segment is coaxial with the output shaft of the servo motor 2. The symmetry axis of the limit disk 3 is located on the line connecting the midpoint of the arc segment and the midpoint of the concave segment.

[0022] This rope-driven bending unit can be used to construct a rope-driven snake-like robotic arm. During implementation, as Figure 1 、 Figure 4As shown in the figure, the cable-driven snake-like robotic arm includes a mounting plate 6 and a number of the aforementioned cable-driven bending units. The cable-driven bending units are connected in sequence. During assembly, the hinge supports 5 of the previous cable-driven bending unit that are far from the limit plate 1 are fixedly connected to the limit plate 1 of the next cable-driven bending unit. The hinge supports 5 of the last cable-driven bending unit that are far from the limit plate 1 are fixedly connected to the mounting plate 6. The mounting plate 6 is used to carry and mount the execution device.

[0023] When the cable-driven snake-like robotic arm is in use, each bending unit can achieve the bending function in a set direction and can maintain the structural stiffness in the bent state. Specifically, taking the bending unit near one end of the mounting plate 6 in the embodiment shown in the figure as an example, this bending unit includes three bending components. By tightening the mounting plate 6 towards the support plate 1 in the bending unit with a cable, it can drive the abutting parts of each bending component to bend inwards (the axial direction of the output shaft of the servo motor 2) until the abutting parts of each bending component abut against the outer circumference of the limit plate 3. Since the limit plate 3 has a symmetric crescent-shaped disc structure and the three bending components are evenly distributed in the circumferential direction, the servo motor 2 can be used to drive the limit plate 3 to rotate so that the midpoint of the concave section of the limit plate 3 faces the abutting part of one of the bending components. When the mounting plate 6 and the support plate 1 are tightened against each other with a cable, the abutting part of this bending component can bend and abut against the midpoint position of the concave section of the limit plate 3 (at the same time, this position is on the axis of symmetry of the limit plate 3, and the abutting parts of the other two bending components abut against the limit plate 3 and are symmetric along this axis of symmetry). Its bending angle is greater than that of the other two bending components. Thus, the entire bending unit can be bent towards the concave section of the limit plate 3, and since the abutting parts of each bending component abut against the outer circumference of the limit plate 3, the structural stiffness in this bent state can be maintained when the cable continuously provides the tension to tighten the mounting plate 6 and the support plate 1 against each other. Figure 4 In the above embodiment, three bending components are evenly distributed in the inner circumference of the cable-driven bending unit. It can achieve bending in three directions (with a 120-degree phase difference between adjacent directions) under cable drive and maintain the structural stiffness during bending. It should be understood that during implementation, any odd number of bending components more than three can also be set. Since the bending components are evenly distributed in the circumferential direction, when the abutting part of one of the bending components bends and abuts against the midpoint position of the concave section of the limit plate 3, the abutting parts of the other bending components abut against the outer circumference of the limit plate 3 and are divided into two groups symmetric along the axis of symmetry of the limit plate 3. Thus, by setting multiple bending components, multi-directional bending under cable drive and maintaining the structural stiffness in the bent state can be achieved.

[0024]

[0025] Figure 1 Figure 3 Figure 1 、 Figure 3As shown in the figure, the cable-driven snake-like robotic arm further includes a number of driving mechanisms. Each driving mechanism includes a driving motor 7, a cable reel 8, and a pulling cable 9. During implementation, a workbench is also provided. The driving motor 7 and the limit disk 1 in the cable-driven bending unit away from the mounting disk 6 are both fixedly installed on the workbench. The cable reel 8 is fixedly sleeved on the output shaft of the driving motor 7. One end of the pulling cable 9 is fixedly wound around the cable reel 8, and the other end of the pulling cable 9 sequentially passes through a number of limit disks 1 and is fixedly connected to the mounting disk 6. The number of the driving mechanisms corresponds to the number of bending components in each cable-driven bending unit, and a number of pulling cables 9 are respectively arranged close to a number of bending components. When the driving motor 7 rotates, it can drive the cable reel 8 to rotate, so that the pulling cable 9 is gradually wound around the cable reel 8. When winding, the other end of the pulling cable 9 acts on the mounting disk 6 to provide a pulling force. When all the driving mechanisms work, the mounting disk 6 can be tightened towards the workbench direction through the pulling cables 9, that is, cable drive is realized. It should be noted that during this cable drive process, in addition to tightly pulling the mounting disk 6 and the adjacent support disk 1 close to it through the rope as described above, the adjacent two support disks 1 are also tightly pulled synchronously. At this time, the bending direction of each bending unit can be adjusted through the control of the servo motor 2 in each bending unit, and then the bending direction of the entire robotic arm can be adjusted. And because each bending unit maintains a certain stiffness in the bending state, the entire robotic arm also realizes stiffness maintenance when bending and can carry a large load.

[0026] During specific implementation, a limit pin is further provided on each hinge support 5. The limit pin is used to block the side of the connecting rod 4 away from the limit disk 3, so as to limit the angle of the abutting part swinging away from the axis direction of the output shaft of the servo motor 2, so that the abutting part can only bend towards the limit disk 3 in the cable drive tightening state, ensuring the reliability of the cable drive.

[0027] Furthermore, in each bending mechanism, a torsion spring is also provided between the hinge support 5 and the connecting rod 4. The torsion spring is used to provide an elastic force for the abutting part to swing away from the axis direction of the output shaft of the servo motor 2. When the robotic arm is in the bending state, the pulling cable 9 can be released by reversing the rotation of each driving motor 7. At this time, under the action of each torsion spring, the robotic arm can be reset to a straight state. It should be understood that setting the torsion spring is only a preferred implementation form. In some specific scenarios, such as when the robotic arm is used vertically and the mounting disk 6 is located directly below the entire robotic arm, the torsion spring can also not be installed. After the pulling cable 9 is released, the entire robotic arm can be reset under the action of its own weight.

[0028] The above description is only a preferred implementation manner of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. And any changes and modifications made by those skilled in the art without departing from the spirit and scope of the present invention should fall within the protection scope of the appended claims of the present invention.

Claims

1. A cable-driven bending unit, characterized in that, It includes a support disc, a steering gear, a limit disc and a number of bending components. The steering gear is fixedly installed on the support disc. The limit disc is fixedly connected to the output shaft of the steering gear. A number of the bending components are circumferentially evenly distributed around the output shaft of the steering gear, and the number of the bending components is an odd number of three or more. The bending component includes two bending mechanisms. The bending mechanism includes a hinge support and a connecting rod. One ends of the two connecting rods are respectively rotatably connected to the two hinge supports, and the other ends of the two connecting rods are rotatably connected to each other. A position where the two connecting rods are connected forms an abutting portion. One hinge support is fixedly connected to one end of the support disc, and the other hinge support is adapted to the other end of the support disc. The abutting portion can be bent along the radial direction of the output shaft of the steering gear towards the axis direction of the output shaft of the steering gear. The limit disc has a symmetric crescent-shaped disc structure. The symmetry axis of the limit disc is parallel to the radial direction of the output shaft of the steering gear. A number of the abutting portions are all adapted to the outer circumference of the limit disc.

2. The cable-driven bending unit according to claim 1, wherein, A limit pin is arranged on the hinge support, and the limit pin is used to limit the swinging angle of the abutting portion away from the axis direction of the output shaft of the steering gear.

3. The cable-driven bending unit according to claim 2, characterized in that, A torsion spring is further arranged between the hinge support and the connecting rod in the bending mechanism, and the torsion spring is used to provide an elastic force for the abutting portion to swing away from the axis direction of the output shaft of the steering gear.

4. A cable-driven bending unit according to claim 1, characterized in that, The outer circumference of the limit disc includes an arc segment and a concave segment. Two ends of the arc segment are respectively connected to two ends of the concave segment, and the arc segment is coaxial with the output shaft of the steering gear.

5. A cable-driven snake-like robotic arm, characterized in that, It includes a mounting disc and a number of rope-driven bending units as described in any one of claims 1 to 4. A number of the rope-driven bending units are connected in sequence. The hinge supports far from the limit disc in the previous rope-driven bending unit are all fixedly connected to the limit disc in the next rope-driven bending unit. The hinge supports far from the limit disc in the last rope-driven bending unit are all fixedly connected to the mounting disc.

6. A cable-driven snake-like robotic arm according to claim 5, characterized in that, It further includes a number of driving mechanisms. The driving mechanism includes a driving motor, a wire reel and a pulling rope. The driving motor is fixedly connected to the limit disc in the rope-driven bending unit far from the mounting disc. The wire reel is fixedly sleeved on the output shaft of the driving motor. One end of the pulling rope is fixedly wound on the wire reel, and the other end of the pulling rope passes through a number of the limit discs in sequence and is fixedly connected to the mounting disc; in each of the rope-driven bending units, a number of the pulling ropes are respectively arranged close to a number of the bending components.

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