CN113183178B - Flexible joint and robot - Google Patents

Abstract

The invention relates to the technical field of robots, and discloses a flexible joint which comprises a plurality of joint units, wherein each joint unit comprises a first supporting piece, a second supporting piece, an inner spring and a plurality of outer springs, two ends of each inner spring and two ends of each outer spring are respectively connected with the first supporting piece and the second supporting piece, the projections of the plurality of outer springs on a plane vertical to the inner springs are sequentially connected to form a ring, the inner springs are positioned in the ring formed by the plurality of outer springs, the self-balancing performance is realized, so that the joint is stable, when the first supporting piece is subjected to external force which enables the first supporting piece to rotate relative to the second supporting piece, the restoring force of the outer spring can be balanced with the external force, deformation stability and restoration are facilitated, and environmental adaptability and deformation flexibility are better. In addition, the invention also provides a robot adopting a plurality of flexible joints to be axially connected in series.

Description

A flexible joint and robot

technical field

The invention relates to the technical field of robots, in particular to a flexible joint and a robot.

Background technique

Continuous robots are widely used in industry, medical care, life, special operations and other fields. Most of their structures are that several connecting rods are connected together by ball hinges or Hooke hinges, which have the characteristics of high flexibility and large deformation. However, such robots based on rigid joints are prone to rigid collisions and are difficult to adapt to interactive operations with complex objects in unstructured environments. Therefore, it is of great significance to develop robotics with flexible joints.

Chinese invention patent application CN110802584A (published on February 18, 2020) discloses a rope-driven multi-joint flexible manipulator, which includes several joint rod units connected in series along the axis direction. In any two adjacent joint rod units, The bottom part of one joint rod unit is sleeved on the top end of the other joint rod unit, and the top end of one joint rod unit and the top end of the other joint rod unit are flexibly connected through a spring assembly, and the bottom end of one joint rod unit is connected with the other joint rod unit. The top end of a joint rod unit is flexibly connected through a spring assembly, and the joint rod unit is provided with a number of rope holes. In this patent, the joint rod unit includes an annular bracket, at least three legs and a concentrator. One end of the legs is connected to the annular bracket and is evenly distributed along the circumference of the annular bracket, and the other ends of the legs are converged and connected to the concentrator. The three circumferentially arranged outer springs are connected to the annular brackets of the adjacent joint rod units, and the concentrator is located in the annular brackets of the adjacent joint rod units and connected to the annular brackets through the three radially distributed inner springs. When the joint lever unit of this patent is used alone, if an external force is applied to rotate the upper ring frame relative to the lower ring frame, both the outer spring and the inner spring are difficult to provide reaction force to maintain the stability and recovery of deformation. In addition, at least three outer springs need to be connected between the annular brackets of the patent, and the coordination of the three outer springs needs to be controlled in terms of axial expansion and contraction, which increases the difficulty of control, and because the outer springs are arranged outside, it is not conducive to the installation of the skin. It is easy to be limited by the skin, and when the joint rod unit is impacted by external force, it will directly contact the outer spring, which is easy to cause damage to the outer spring.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flexible joint and a robot with stronger environmental adaptability and better deformation flexibility.

In order to achieve the above object, the present invention provides a flexible joint, including several joint units, the joint unit includes a first support, a second support, an inner spring and a plurality of outer springs, the inner spring and the outer spring Both ends of the spring are connected to the first support member and the second support member respectively, and the projections of the outer springs on a plane perpendicular to the inner spring are connected in sequence to form a ring shape, and the inner spring is located in a ring shape surrounded by a plurality of the outer springs; the opposite sides of the first support member and the second support member are respectively concave to form at least two end portions, and the end portions of the first support member and the ends of the second support members are arranged staggered in the circumferential direction, and the two ends of the outer spring are respectively connected with the end of the adjacent first support member and the end of the second support member, so Both ends of the inner spring are respectively connected to the inner recess of the first support member and the inner recess of the second support member; the first support member and the second support member are C-ring structures, And the openings of the first support member and the second support member are opposite to each other and are arranged in a vertical intersection; when the joint units are arranged in two or more, in any two adjacent joint units , the first support of one joint unit and the second support of the other joint unit are vertically crossed and connected by connecting rods.

As a preferred solution, the joint unit further includes an annular bracket, the first support member and the second support member are sleeved in the annular bracket, and the first support member or the second support member is connected to the annular bracket. The ring brackets are connected.

As a preferred solution, the free length of the outer spring is smaller than the distance between its connection with the first support and the connection with the second support, and the free length of the inner spring is smaller than its connection with the second support. The distance between the connection of the first support and its connection with the second support.

As a preferred solution, the inner spring and the outer spring are shape memory alloy springs or elastic cords.

The present invention also provides a robot, comprising the above-mentioned flexible joints, the flexible joints are connected in series along the axis direction through driving ropes, and the driving ropes pass through the annular supports of the flexible joints in sequence.

As a preferred solution, a driving device is also included, the driving device includes a driving unit, and the driving unit is connected with the driving rope to drive the driving rope to expand and contract.

As a preferred solution, the driving device further includes a top plate and a bottom plate, the driving unit is located between the top plate and the bottom plate, the driving unit includes a motor, a screw rod and a slider, and the motor is connected to the bottom plate One end of the screw rod is connected to the motor, the other end of the screw rod is rotatably connected to the top plate, and the slider is sleeved on the screw rod and engaged with the screw rod, The drive cable is connected to the slider.

Compared with the prior art, the beneficial effects of the present invention are:

In the present invention, the first support member and the second support member are connected by the inner spring and the outer spring, and the projections of the outer spring on the plane perpendicular to the inner spring are successively connected to form a ring, and the inner spring is located in the enclosed ring, so that the The outer springs constrain each other in the circumferential direction, and the outer springs and the inner springs constrain each other in the axial direction, forming a tension net, which has self-balancing properties and makes the joint stable. At the same time, the restoring force of the outer spring can be balanced with the external force, which is helpful for the stability and recovery of deformation, and the inner spring is located inside and has a space for free deformation, so that the joint of the present invention has stronger environmental adaptability and better deformation compliance. In addition, the inner spring will not be directly impacted by external force, which can reduce the probability of damage to the inner spring.

Description of drawings

FIG. 1 is a schematic structural diagram of a flexible joint without a ring support according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a flexible joint assembling an annular support and a driving rope according to an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a robot according to an embodiment of the present invention.

FIG. 4 is a schematic structural diagram of the deformation of a robot according to an embodiment of the present invention.

FIG. 5 is a schematic structural diagram of a driving device of a robot according to an embodiment of the present invention.

FIG. 6 is a schematic structural diagram of the annular bracket assembly strut of the joint unit closest to the drive device according to the embodiment of the present invention.

In the figure, 1-first support; 2-second support; 3-inner spring; 4-outer spring; 5-connecting rod; 6-pin shaft; 7-installation hole; 8-connecting ring; 9-ring Bracket; 10-drive rope; 11-top plate; 12-bottom plate; 13-motor; 14-screw; 15-slider; 16-bearing; 17-pillar; 18-connecting hole; 19-limiting edge.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "portrait", "horizontal", "top", "bottom", "front", "rear", "left", "right", " The orientations or positional relationships indicated by vertical, horizontal, top, bottom, inside, and outside are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying It is described, rather than indicated or implied, that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed to indicate or imply relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

Also, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

As shown in FIG. 1 , a flexible joint according to a preferred embodiment of the present invention includes several joint units. The joint unit includes a first support member 1 , a second support member 2 , an inner spring 3 and a plurality of outer springs 4 . The inner spring 3 Both ends of the outer spring 4 are connected to the first support 1 and the second support 2, respectively, and the projections of the outer springs 4 on the plane perpendicular to the inner spring 3 are connected in turn to form a ring shape, and the inner spring 3 is located in multiple positions. Inside the ring enclosed by the outer springs 4 . In this embodiment, the first support member 1 and the second support member 2 are connected by the inner spring 3 and the outer spring 4, and the projections of the outer spring 4 on the plane perpendicular to the inner spring 3 are successively connected to form a ring shape, and the inner spring 3 is located at the In the enclosed ring, the outer springs 4 are bound to each other in the circumferential direction, and the outer springs 4 and the inner springs 3 are bound to each other in the axial direction, forming a tension net, which has self-balancing properties and makes the joint stable. When the support member 1 rotates relative to the external force of the second support member 2, the restoring force of the outer spring 4 can be balanced with the external force, which is conducive to the stability and recovery of deformation, and the inner spring 3 is located inside, with a space for free deformation, which makes this implementation The joint of the example has stronger environmental adaptability and better deformation flexibility. In addition, the inner spring 3 will not be directly impacted by external force, which can reduce the probability of the inner spring 3 being damaged.

Further, the opposite sides of the first support member 1 and the second support member 2 are respectively concave to form at least two end portions, and the end portions of the first support member 1 and the end portions of the second support member 2 are arranged staggered in the circumferential direction. , the two ends of the outer spring 4 are respectively connected with the end of the adjacent first support 1 and the end of the second support 2, and the two ends of the inner spring 3 are respectively connected with the inner recess of the first support 1 and the end of the second support 2 respectively. The inner recess of the second support member 2 can facilitate the circumferential connection of the outer spring 4, and the inner recess can cover the inner spring 2 inside. The two supports 2 are in contact with each other, but not in contact with the inner spring 2 , so as to protect the inner spring 2 .

The first support member 1 and the second support member 2 in this embodiment are C-ring structures, and the openings of the first support member 1 and the second support member 2 are opposite to each other and are arranged in a vertical cross. The rigid structure affects the work of the inner spring 3 and the outer spring 4, which is beneficial to improve the flexibility of the joint. And, when there are two or more joint units, in any two adjacent joint units, the first support 1 of one joint unit and the second support 2 of the other joint unit are vertically intersected and arranged and The connection by the connecting rod 5 is beneficial to the consistency of the load distribution path of each joint unit, and the stability of the structure can be improved. In this embodiment, the inner spring 3 is connected to the first support member 1 and the second support member 2 through a pin 6 respectively, and the middle portion of the first support member 1 and the middle portion of the second support member 2 are provided with mounting holes 7 , the end of the inner spring 3 is located in the mounting hole 7 , and the pin 6 passes through the mounting hole 7 to fix the inner spring 3 . Two ends of the first support 1 and the second support 2 are respectively provided with connecting rings 8 , and the ends of the outer springs 4 are connected with the connecting rings 8 .

In addition, as shown in FIG. 2 , the joint unit further includes an annular bracket 9 , the first support 1 and the second support 2 are sleeved in the annular bracket 9 , and the first support 1 or the second support 2 is connected to the annular bracket 9 . 9 connections. The annular bracket 9 can be easily connected to the driving parts such as the driving rope, and can protect the first support 1 and the second support 2 and the inner spring 3 and the outer spring 4 connecting the two, so that the first support 1 and the second support 2 and the inner spring 3 and outer spring 4 connecting the two are not in direct contact with the external force of the impact, and there is also enough space for the inner spring 3 and the outer spring 4 to work.

In this embodiment, the free length of the outer spring 4 is smaller than the distance between its connection with the first support 1 and the connection with the second support 2, and the free length of the inner spring 3 is smaller than the distance between its connection with the first support 1 and the connection with the second support 2 The distance between the connection of the support 1 and the connection with the second support 2 is such that the outer spring 4 and the inner spring 3 are both in a stretched state under the action of no external force, so that the joint has a pre-tensioned state. Tightening force, enhance stability, can quickly provide a balanced reaction force when deformed by external force, and have better self-balancing. The second support 2 is fixed, and the force of the first support 1 is analyzed. Since the outer spring 4 is short, the outer spring 4 is stretched. In the circumferential direction, the forces generated by the outer springs 4 are balanced. In the axial direction, the outer spring 4 provides an upward pulling force to the first support member 1. Since the inner spring 3 is stretched, the inner spring 3 provides a downward pulling force to the first support member 1. Therefore, in the axial direction, the maintain balance. The inner spring 3 and the outer spring 4 in this embodiment belong to tension springs, which together with the rigid first support member 1 and the second support member 2 form a tension integral structure, which can maximize the use of the characteristics of materials and cross-sections, and can use as much as possible Use less material to build larger span structures. And the inner spring 3 and outer spring 4 use tension springs, which can be lighter. If a compression spring is used as a support, a larger size and a thicker spring wire are generally required to have a strong supporting force, and the overall tension depends on rigidity. The flexible spring plays an auxiliary role in stabilization, and the spring does not play a supporting role. Therefore, if the spring is only in tension, a finer spring, or even an elastic cord, can be selected. In addition, the compression spring is easy to become unstable. When the ratio of the height to the diameter of the spring is large, if the compression force exceeds a certain limit, the spring will undergo large lateral bending, which will lead to loss of stability, resulting in uncontrollable structure and unclear mechanical properties. The tension spring, on the other hand, keeps the axis straight at all times. In addition, the tension spring is more flexible, and the connection point of the tension spring is not limited; the installation position of the compression spring needs to be clear. If the direction of action of the pressure is not along the axis, the spring will not only be under pressure, but also be subjected to bending moment, which is easy to become unstable. . The direction of action of the tensile force of the tension spring can be changed in real time with the deformation of the structure, and the axis is kept straight. In addition, the tension spring has a wider range of motion, and the compression spring generally has a smaller compression range. After the spring wire coil is pressed tightly, it can no longer be pressed. The tension spring stretches more, so the structure has a greater range of motion.

Optionally, the inner spring 3 and the outer spring 4 can also be shape memory alloy springs, and the joint can be deformed by changing the temperature without using a driving member. When a shape memory alloy spring is used, only one inner spring 3 can be used to realize telescopic and variable stiffness control. In addition, the inner spring 3 and the outer spring 4 can also use elastic cords.

As shown in FIG. 3 and FIG. 4 , this embodiment further provides a robot, which includes the above-mentioned flexible joints, and the flexible joints are connected in series along the axis direction through driving ropes 10 in sequence. By controlling the length of the driving rope 10 to change in coordination, the robot can then be controlled to bend and stretch and deform. The driving rope 10 is kept in a tensioned state, and the shape of the robot is determined by the length of the driving rope 10. The length of the driving ropes 10 can be changed (extended or shortened) through the cooperation of the driving ropes 10, and the relative rotation of the flexible joints can be driven to realize the robot in any direction. bending deformation. There are four driving ropes 10 in this embodiment, and they are evenly arranged along the circumferential direction of the annular support 9 . The springs of the flexible joints help stabilize the overall structure, allowing the robot to reach a stable state even when some of the ropes are slack.

Further, the robot further includes a driving device, the driving device includes a driving unit, and the driving unit is connected with the driving rope to drive the driving rope 10 to expand and contract. As shown in FIG. 6 , the driving device further includes a top plate 11 and a bottom plate 12, the driving unit is located between the top plate 11 and the bottom plate 12, the driving unit includes a motor 13, a screw rod 14 and a slider 15, the motor 13 is connected to the bottom plate 12, and the screw One end of the rod 14 is connected to the motor 13, the other end of the screw rod 14 is rotatably connected to the top plate 11, the slider 15 is sleeved on the screw rod 14 and is engaged with the screw rod 14, the driving rope 10 is connected to the slider 15, The motor 13 drives the screw rod 14 to rotate, so that the slider 15 moves along the screw rod 14, and the driving rope 10 can be controlled to extend or retract the driving device. The screw rod 14 in this embodiment is connected with the top plate 11 through the bearing 16 . In addition, the annular support 9 of the joint unit closest to the drive device is connected to the top plate 11 through the support 17, the support 17 is set to four, the support support 17 is vertically connected to the annular support 9, the top plate 11 is provided with a connecting hole 18, the support support 17 is inserted Connected in the connecting hole 18, the driving device and each joint are connected into one body, and the support 17 has a certain distance between the joint unit closest to the driving device and the driving device, which is conducive to the retraction and retraction of the driving rope 10. The bottom of the strut 17 in this embodiment is provided with a limit edge 19 for limiting the length of the strut 17 extending into the connecting hole 18 . In addition, in this embodiment, the diameter of the annular bracket 9 of the part of the joint unit at one end away from the driving device gradually decreases along the direction away from the driving device, forming a tail shape, making the robot shape like a fish. Therefore, this embodiment only needs to change The size of the ring support 9 can change the shape of the robot without changing the spring connection method and structure, and has high adaptability.

To sum up, the embodiment of the present invention provides a flexible joint, which connects the first support 1 and the second support 2 through the inner spring 3 and the outer spring 4, and the projection of the outer spring 4 on a plane perpendicular to the inner spring 3 The inner springs 3 are located in the enclosed ring, so that the outer springs 4 are bound to each other in the circumferential direction, and the outer springs 4 and the inner springs 3 are bound to each other in the axial direction to form a tension net with self-balancing. When the first support 1 is rotated relative to the second support 2, the restoring force of the outer spring 4 can be balanced with the external force, which helps to stabilize and restore the deformation, and the inner spring 3 is located in Inside, there is a space for free deformation, so that the joint of this embodiment has stronger environmental adaptability and better deformation flexibility. In addition, the inner spring 3 will not be directly impacted by external force, which can reduce the probability of damage to the inner spring 3 . In addition, this embodiment also provides a robot composed of a plurality of the above-mentioned flexible joints connected in sequence in the axial direction.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and replacements can be made. These improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (7)

1. A flexible joint, characterized by comprising several joint units, the joint units comprising a first support (1), a second support (2), an inner spring (3) and a plurality of outer springs (4) , both ends of the inner spring (3) and the outer spring (4) are connected to the first support (1) and the second support (2) respectively, and each of the outer springs (4) ) projections on a plane perpendicular to the inner spring (3) are successively connected to form a ring, and the inner spring (3) is located in the ring formed by a plurality of the outer springs (4); The opposite sides of the first support (1) and the second support (2) are concave to form at least two ends respectively, and the end of the first support (1) and the second support The ends of the supports (2) are staggered in the circumferential direction, and the two ends of the outer spring (4) are respectively connected to the ends of the adjacent first supports (1) and the second supports (2). ) are connected to the ends of the inner spring (3), and the two ends of the inner spring (3) are respectively connected to the inner recess of the first support (1) and the inner recess of the second support (2); The first support member (1) and the second support member (2) are C-shaped ring structures, and the openings of the first support member (1) and the second support member (2) are opposite to each other and are in a shape. vertical cross arrangement; When the number of the joint units is two or more, in any two adjacent joint units, the first support member (1) of one joint unit and the other joint unit The said second supports (2) are vertically crossed and connected by connecting rods (5). 2. The flexible joint according to claim 1, wherein the joint unit further comprises an annular bracket (9), the first support (1) and the second support (2) are sleeved on inside the annular support (9), and the first support (1) or the second support (2) is connected with the annular support (9). 3. The flexible joint according to claim 2, characterized in that the free length of the outer spring (4) is smaller than the connection between the outer spring (4) and the first support (1) and the second support (2) The distance between the junctions, the free length of the inner spring (3) is smaller than its junction with the first support (1) and its connection with the second support (2) distance between. 4. The flexible joint according to claim 2, wherein the inner spring (3) and the outer spring (4) are shape memory alloy springs or elastic ropes. 5. A robot, characterized in that it comprises a plurality of flexible joints according to any one of claims 2-4, the flexible joints are connected in series along the axis direction of the flexible joints in sequence by driving ropes (10), and the driving ropes (10) ) pass through the annular brackets (9) of the flexible joints in sequence. 6. The robot according to claim 5, further comprising a driving device, the driving device comprising a driving unit, and the driving unit is connected with the driving rope (10) to drive the driving rope (10) telescopic. 7. The robot according to claim 6, characterized in that, the driving device further comprises a top plate (11) and a bottom plate (12), and the driving unit is located between the top plate (11) and the bottom plate (12) In the meantime, the drive unit includes a motor (13), a screw (14) and a slider (15), the motor (13) is connected to the bottom plate (12), and one end of the screw (14) is connected to the The motor (13) is connected, the other end of the lead screw (14) is rotatably connected to the top plate (11), and the slider (15) is sleeved on the lead screw (14) and is connected to the top plate (11). The lead screw (14) is engaged, and the driving rope (10) is connected to the slider (15).

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