WO2020173009A1

WO2020173009A1 - Flexible mechanical arm based on sphere-pin pairs

Info

Publication number: WO2020173009A1
Application number: PCT/CN2019/088982
Authority: WO
Inventors: 梁斌; 刘宇; 朱先进; 王学谦; 孟得山; 陈章
Original assignee: 清华大学深圳研究生院
Priority date: 2019-02-25
Filing date: 2019-05-29
Publication date: 2020-09-03
Also published as: CN109773769A; CN109773769B

Abstract

A flexible mechanical arm based on sphere-pin pairs, comprising a plurality of arm rod segments (10), a plurality of linkage rope groups (30) and a plurality of drive ropes (40); the plurality of arm rod segments (10) are connected in sequence in an end-to-end manner; every two adjacent arm rod segments (10) are connected by means of a sphere-pin pair (20), each linkage rope group (30) corresponds to the respective arm rod segment (10) of which the two ends are connected to the sphere-pin pair (20), each linkage rope group (30) comprises a plurality of linkage ropes, the plurality of linkage ropes in each linkage rope group (30) bypass, in sequence, the sphere-pin pair (20) at a first end of the corresponding arm rod (10), the corresponding arm rod (10) and the sphere-pin pair (20) at a second end of the corresponding arm rod (10), so as to achieve linkage, and each linkage rope is S-shaped on the corresponding arm rod (10); and the plurality of drive ropes (40) pass through the plurality of arm rod segments (10) connected in sequence in the end-to-end manner, so as to realize driving of the plurality of arm rod segments (10). The flexible mechanical arm based on the sphere-pin pairs (20) facilitates engineering applications and has a stable and reliable linkage effect, achieving bending linkage at an equal curvature.

Description

A flexible mechanical arm based on ball pin pair

Technical field

The invention relates to the technical field of mechanical arms, in particular to a flexible mechanical arm based on a ball pin pair.

Background technique

Different from the traditional articulated tandem manipulator, the flexible manipulator has the advantages of high flexibility and strong obstacle avoidance ability. It has strong movement and operation ability in small spaces and complex environments. It has the advantages of aerospace manufacturing, large-scale equipment inspection and maintenance, etc. Important application value. In the prior art, each joint of the flexible manipulator is independently driven. Although the redundancy of the entire arm can be improved, the number of driving motors will be increased accordingly, resulting in the difficulty, weight, and cost of the flexible arm. increase.

In order to solve the problem of the large number of driving motors, the existing solution is to add elastic elements between the joints, and use a section of the arm as a control unit for control, or directly use elastic materials as the arm base for control to achieve arc-like deformation movement. The shape of the robot arm in the actual movement process is deviated from the arc, and the end accuracy is not high, which is difficult to meet the demand.

Fig. 1a and Fig. 1b show a gear-driven equal-curvature bending mechanical arm of prior art 1. A large bevel gear is mounted on a rotating support through interference or key fit with a pin, and one is connected to the large bevel gear. The small bevel gear that is engaged with the transmission shaft is installed at one end of the transmission shaft close to the universal joint by interference or key fit, and the intersection of the center line of the large bevel gear and the small bevel gear is located at the rotation center of the universal joint. The mechanical arm has the following disadvantages: (1) the gear transmission mechanism occupies a large space, which affects the applicable scenarios of the flexible arm; (2) only realizes the linkage on a single degree of freedom, which limits the flexible arm's motion capability. Chinese patent document CN106625639A discloses a flexible arm linkage joint section of the prior art 2, which has the following disadvantages: (1) The number of articulated rods in the arm section of this solution must be a multiple of 4, which is not convenient for the number of joint sections in the arm. Configuration; (2) During the linkage process of the remote linkage rope in this scheme, the pitch and yaw angles will affect the shape of the remote linkage rope, which in turn affects the effect of the linkage; (3) the remote linkage rope pole in this solution Occupies a large amount of the internal space of the boom, which affects the wiring of the end actuator cable of the boom solution, which is not conducive to the practical application of the solution; (4) In this solution, the shape of the remote linkage rope will change during the movement. Deformation causes a change in the pretension of the cable, which results in a change in the positive pressure between the joint rod of the arm section and the center block. The pre-tightening force of the "8"-shaped stainless steel rope on the opposite side can be regarded as a fixed value; during the movement of the boom, the eccentric load caused by the different positive pressures on both sides will also affect the angle of the boom. The precision of linkage; thereby reducing the overall control precision of the boom. In addition, none of the above solutions can realize the backup of the linkage rope on all two degrees of freedom.

The disclosure of the above background technical content is only used to assist the understanding of the concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application Under circumstances, the above-mentioned background technology should not be used to evaluate the novelty and inventive step of this application.

Summary of the invention

In order to solve the above technical problems, the present invention proposes a flexible mechanical arm based on a ball-and-pin pair, which is more convenient for engineering applications, has stable and reliable linkage effects, and realizes equal-curvature bending linkage.

In order to achieve the above effects, the present invention adopts the following technical solutions:

The invention discloses a flexible mechanical arm based on a ball pin pair, which includes a multi-segment arm rod, a multi-group linkage rope group and a plurality of driving ropes. The multi-segment arm rods are respectively connected end to end in sequence, and each of the two adjacent segments The arm rods are connected by a ball pin pair, and each group of the linkage rope group corresponds to each section of the arm rod with the ball pin pair connected at both ends, and each group of the linkage rope group includes multiple linkage ropes, A plurality of said interlocking ropes in each group of interlocking ropes respectively bypass the corresponding ball pin pair of the first end of the arm, the corresponding arm and the corresponding The ball pin pair at the second end of the arm rod realizes linkage, and each of the linkage ropes is S-shaped on the corresponding arm rod; a plurality of the driving ropes respectively pass through a plurality of sections connected end to end in sequence. The arm rod is used to realize the driving of multiple sections of the arm rod.

Preferably, the ball pin pair includes a first ball cavity, a second ball cavity and a pin shaft, the first ball cavity is fixedly connected to the first end of the arm, and the second ball cavity Is disposed in the first spherical cavity, and the pin shaft passes through the first spherical cavity and the second spherical cavity in order to make the first spherical cavity and the second spherical cavity in The degree of freedom of rotation in the axial direction of the arm rod is restricted and relatively rotatable in two directions perpendicular to the axial direction of the arm rod, wherein the second spherical cavity can be inserted into the phase The second end of the adjacent arm rod is connected with the second end of the adjacent arm rod by a key to form the ball pin pair.

Preferably, the first ball cavity or the second ball cavity is provided with a sliding groove, and the length of the sliding groove is arranged along the axial direction of the arm rod, wherein the first ball cavity When the cavity is provided with a sliding groove, the pin is threaded or interference fit with the second spherical cavity, and when the second spherical cavity is provided with the sliding groove, the pin and the first Ball cavity threaded connection or interference fit.

Preferably, each of the ball pin pairs includes two pin shafts, and the two pin shafts respectively pass through the first spherical cavity body and the second spherical cavity body in sequence, wherein the two pin shafts are symmetrical It is arranged at two ends of the first spherical cavity and the second spherical cavity, and the axes of the two pin shafts are collinear.

Preferably, the second spherical cavity body is composed of at least two spherical cavity body parts, wherein at least two of the spherical cavity body parts are spliced with each other to form the second spherical cavity body.

Preferably, a plurality of key grooves are provided in the second spherical cavity, and a plurality of protruding keys are provided on the second end of the arm rod, and the plurality of keys can be respectively inserted into the plurality of key grooves. And at the second end of the arm rod is also provided with a stopper, the second spherical cavity and/or the end of the first spherical cavity is provided with a thrust surface, the stopper The rear part of the plurality of keys is arranged to stop the thrust surface at the end of the second spherical cavity and/or the first spherical cavity in the axial direction of the arm rod.

Preferably, two ends of the multiple linkage ropes in each linkage rope group are respectively fixedly connected to the two sections of the arm rods respectively connected to the two ends of the corresponding arm rods.

Preferably, each interlocking rope group includes at least three interlocking ropes, and the three interlocking ropes are respectively distributed on the circumference of the corresponding arm rod without interfering with each other.

Preferably, both ends of each arm rod are respectively provided with first flanges, the first flange is provided with a plurality of first holes and a plurality of second holes, and the ball pin pair is provided with a first flange. Two flanges, the second flange is provided with a plurality of third holes, the first hole, the second hole and the third hole are respectively arranged along the axial direction of the arm, each The first end of the linkage rope is fixedly connected to the first hole of the first flange of the second end of the arm rod connected to the corresponding first end of the arm rod, and the second end Fixedly connected to the first hole of the first flange of the first end of the arm rod connected to the second end of the corresponding arm rod, and the first end of each link rope is connected to The second end passes through the third hole of the second flange on the ball pin pair of the first end of the corresponding arm rod, and the first end of the corresponding arm rod in turn The second hole on the first flange, the second hole on the first flange corresponding to the second end of the arm rod, and the corresponding second hole on the second end of the arm rod The third hole of the second flange of the ball pin pair; further, each of the linkage ropes is on the first flange of the first end of the corresponding arm rod The second hole and the second hole on the first flange of the second end of the corresponding arm rod are in an S shape; furthermore, each of the linkage ropes is also correspondingly provided S-shaped copper sleeve, the S-shaped copper sleeve is sleeved on the second hole on the first flange of the first end of the corresponding arm rod and the second hole of the corresponding second end of the arm rod On the linkage rope between the second holes on the first flange, and the second holes are stepped holes to fix both ends of the S-shaped copper sleeve.

Preferably, between the first end of each linkage rope and the second hole on the first flange of the corresponding first end of the arm rod, and the second end and the corresponding The second holes on the first flange of the second end of the arm rod are arranged along the axial direction of the arm rod; further, at least one threaded hole is correspondingly provided on the first hole The threaded hole is perpendicular to the first hole so that at least one screw can penetrate into the at least one threaded hole to fix the first end or the second end of the linkage rope.

Compared with the prior art, the beneficial effect of the present invention is that the flexible mechanical arm based on the ball pin pair disclosed in the present invention adopts a modular manner, and every two adjacent sections of arm rods are connected by the ball pin pair, and each group of linked ropes The group corresponds to each arm with a ball pin pair connected at both ends, which is convenient for engineering application, stable and reliable linkage effect, and realizes equal curvature bending linkage; wherein the linkage rope is combined with the ball pin pair to make the linkage rope The actual working disc diameter is close to the maximum outer diameter of the arm. When the maximum outer diameter of the arm is constrained, the linkage effect of the flexible manipulator is better and the accuracy is higher; and each group of linkage rope groups can be set according to actual needs. The linkage rope realizes the backup of the linkage rope and improves the reliability of the boom. In addition, due to the modular approach, the number of joint segments can be arbitrarily configured. By resetting the length of the arm of each joint segment, etc., the solution is more convenient and flexible in actual engineering application design; Compared with the existing technical solutions, the number of component parts of the robotic arm is also greatly reduced, the structure is simple, the arm composition is simpler, the assembly workload is reduced, the reliability is higher, it is convenient for miniaturization, lightweight design, and space utilization. High; In addition, the central space of the boom is largely reserved, which is used for the power cables, signal cables and trachea needed by the fiber laser for passing through the end tools, which improves the diversity and working ability of the end tools ; And the motor utilization is high, only need to use the motor to drive multiple driving ropes, the linkage rope corresponding to each arm rod automatically realizes the curvature bending linkage according to the drive, with higher precision and enhanced controllability.

Description of the drawings

Figure 1a is a schematic cross-sectional view of a gear-driven mechanical arm with constant curvature bending in the prior art;

Fig. 1b is a side view of a mechanical arm with constant curvature bending based on gear transmission in the prior art;

Fig. 2 is a schematic structural diagram of one end of a flexible mechanical arm of a preferred embodiment of the present invention;

Fig. 3 is a schematic structural diagram of a middle section of a flexible mechanical arm according to a preferred embodiment of the present invention;

4 is an exploded schematic view of the ball pin pair of the flexible mechanical arm of the preferred embodiment of the present invention;

Figure 5 is a schematic view of the structure of the small hemisphere in Figure 4;

Figure 6 is a schematic view of the structure of the arm in Figure 4;

Fig. 7 is a schematic structural diagram of the pin shaft in Fig. 4;

FIG. 8 is a schematic structural diagram of an articulation pair of a flexible mechanical arm according to a preferred embodiment of the present invention;

Figure 9 is a schematic structural diagram of a "spherical S"-shaped linkage rope of a flexible mechanical arm in a preferred embodiment of the present invention;

10 is a schematic cross-sectional view of the "spherical S"-shaped linkage rope of the flexible mechanical arm of the preferred embodiment of the present invention after assembly;

Fig. 11 is a schematic diagram of the principle of the "spherical S"-shaped linkage rope of the flexible mechanical arm of the preferred embodiment of the present invention.

detailed description

The present invention will be further described below with reference to the drawings and combined with preferred embodiments.

As shown in Figures 2 and 3, the preferred embodiment of the present invention discloses a flexible mechanical arm based on a ball pin pair, which includes a multi-segment arm 10, a multi-group linkage rope group 30, and a plurality of driving ropes 40. Connected end to end, each of the two adjacent segments of the arm 10 is connected by a ball pin pair 20, and each group of linkage rope groups 30 corresponds to each segment of the arm 10 with a ball pin pair 20 connected at both ends, each group The interlocking rope group 30 includes three interlocking ropes, and the three interlocking ropes in each interlocking rope group 30 respectively pass around the ball pin pair 20 at the first end of the corresponding arm 10, the corresponding arm 10, and the corresponding The ball pin pair 20 at the second end of the corresponding arm 10 realizes linkage, and each linkage rope is S-shaped on the corresponding arm 10; a plurality of driving ropes 40 respectively pass through the multi-segment arm 10 connected end to end in sequence. In order to realize the driving of the multi-segment arm rod 10, the rope heads 41 of the plurality of driving ropes 40 are fixed on the arm rod 10 at one end.

As shown in Figure 4, the arm 11 and the arm 12 are connected by a ball pin pair 21. The ball pin pair 21 includes a first ball cavity 210, a second ball cavity 220, and pin

shafts

311, 312. The first ball cavity 210 Fixedly connected to the first end of the arm 11, the second spherical cavity 220 is formed by splicing the

small hemispheres

211 and 212 with each other. The

small hemispheres

211 and 212 are placed in the first spherical cavity 210, and the

pins

311 and 312 are respectively Pass through the first spherical cavity 210 and the second spherical cavity 220 in sequence so that the first spherical cavity 210 and the second spherical cavity 220 are relatively fixed in the circumferential direction of the cross section of the

arm rods

11 and 12 and are positioned on the arm rods. 11 and 12 are relatively movable in the axial direction, wherein the second spherical cavity 220 can be sleeved on the second end of the arm rod 12 and connected with the second end of the arm rod 12 through a key to form a ball pin pair 21.

5 and 6, the first spherical cavity 210 is provided with a threaded hole 2101, the small hemisphere 211 (212) is provided with a sliding groove 2111 (2121), the length of the sliding groove 2111 (2121) is along the

arm

11 , 12 in the axial direction; combined with Figure 7, the pin 311 (312) is provided with an external thread 3111 (3121) and a mating surface 3112 (3122), of which the external thread 3111 (3121) is threadedly connected with the threaded hole 2101, The mating surface 3112 (3122) slides in the sliding groove 2111 (2121).

The small hemisphere 211 (212) is provided with multiple key grooves 2112 (2122), and the second ends of the

arm rods

11 and 12 are provided with multiple protruding keys 411. The multiple keys 411 can be inserted into the multiple key grooves 2112 respectively. (2122) to realize the key connection, and the second end of the

arm rods

11, 12 is also provided with a stop 412, the end of the small hemisphere 211 (212) is provided with a thrust surface 2113 (2123), the stop 412 is provided at the tail of the plurality of keys 411 to stop the thrust surface 2113 (2123) of the end of the small hemisphere 211 (212) in the axial direction of the

arm rods

11 and 12.

The

pin shafts

311, 312 are symmetrically arranged at the two ends of the first spherical cavity 210 and the second spherical cavity 220, and the axes of the

pin shafts

311, 312 are collinear, that is, the two threaded holes provided on the first spherical cavity 210 The axes of 2101 are collinear, and the

key grooves

2112, 2122 provided on the

small hemispheres

211, 212 are symmetrically arranged at both ends of the second spherical cavity.

The installation process of the ball pin pair 21 is: placing the

small hemispheres

211, 212 in the first spherical cavity 210 of the arm 11, using the

external threads

3111, 3121 of the

pin shafts

311, 312 and the threads of the first spherical cavity 210 The holes 2101 are matched. At this time, the mating surfaces 3112, 3122 of the

pins

311, 312 and the sliding

grooves

2111, 2121 of the

small hemispheres

211, 212 respectively form a sliding pair, so that it can slide in the waist-shaped sliding groove; push the arm 12 Into the

small hemispheres

211, 212, so that the protruding key 411 on the arm rod 12 and the

key grooves

2112, 2122 in the

small hemispheres

211, 212 realize a key sliding fit, and push to the thrust surfaces 2113, 2113, of the

small hemispheres

211, 212 2123 is in contact with the stop 412 of the arm rod 12 to form a unit of the arm main structure. In some embodiments, the

pin shafts

311 and 312 may also be connected with the first spherical cavity 210 in an interference fit; in some other embodiments, the sliding groove may also be provided on the first spherical cavity 210, and Correspondingly set threaded holes on the

small hemispheres

211 and 212 can also form a sliding pair.

With reference to Figure 8, the arm 12 and the

small hemispheres

211, 212 are connected by keys to form a moving member. The outer spherical surface of the

small hemispheres

211, 212 of the moving member cooperates with the inner spherical surface of the first spherical cavity 210 of the arm 11 to form a ball. The two

pin shafts

311 and 312 are arranged symmetrically, and the axes are collinear; the

external threads

3111 and 3121 of the heads of the

pin shafts

311 and 312 are connected with the threads of the first spherical cavity 210 on the arm 11, and the pin shaft 311 The mating surfaces 3112, 3122 of 312 and 312 respectively cooperate with the sliding

grooves

2111, 2121 of the

small hemispheres

211, 212; a ball pin pair is formed as a whole, and the ball pin pair has the degree of freedom of rotation around the X and Y axes as shown in Fig. 8, The degree of freedom of rotation about the Z axis is restricted by the

pin shafts

311 and 312; when rotating about the X axis, the axes of the two

pin shafts

311 and 312 are used as the axis of rotation. When rotating about the Y axis, the two

pin shafts

311 and 312 are respectively The

slide grooves

2111 and 2121 of the

small hemispheres

211 and 212 slide inside.

As shown in Figure 9, the arm 11 and the arm 12 are connected by a ball pin pair 21, the arm 12 and the arm 13 are connected by a ball pin pair 22, and the linkage rope is connected between the arm 11 and the arm 13 In between, the ball pin pair 21, the arm rod 12, and the ball pin pair 22 are sequentially bypassed to achieve linkage. In this embodiment, the linkage rope is in the shape of a "spherical S" and is composed of a cable 011, an S-shaped copper sleeve 021,

copper tubes

031, 032,

screws

041, and 042. With reference to Figure 10, the arm 13 is provided with a light hole 13a, Two threaded holes 13b are provided corresponding to the light hole 13a and perpendicular to the light hole 13a. The first ball cavity of the ball pin pair 22 is provided with a limiting hole 13c, and the arm 12 is provided with a stepped hole 12d, in which the light hole 13a, The limit hole 13c and the step hole 12d are arranged along the axial direction of the arm rod; in order to avoid the screw directly squeezing the cable 011, the copper tube 032 is placed on the cable 011, and the screw 042 is inserted into the threaded hole 13b It is fixed in the optical hole 13a, and then passed through the limit hole 13c to the stepped hole 12d, and an S-shaped copper sleeve 021 is placed at 12d. The other side is exactly the same. The S-shaped copper sleeve 021 and the cable 011 are inserted together The stepped hole 12e passes through the limiting hole 11c, and finally provides a certain pre-tightening force to the other end of the cable 011, and then is sleeved into the copper tube 031, and the screw 041 penetrates into the threaded hole 11b to be compressed and fixed. The

copper tubes

031 and 032 can prevent the two ends of the cable 011 from being directly squeezed, and the S-shaped copper sleeve 021 can reduce friction. Among them, in this embodiment, the

light holes

13a, 11a, and the stepped

holes

12d, 12e are respectively provided on the flange 100 of the arm, and flanges 100 are respectively provided at both ends of the arm, and each flange 100 is There are a plurality of light holes and a plurality of stepped holes, respectively corresponding to each interlocking rope to pass through or be fixed; the

limit holes

13c, 11c are respectively provided on the flange 200 of the ball pin pair, and the flange 200 of the ball pin pair is set on At the outer surface of the first spherical cavity. In addition, in some other embodiments, the two ends of the cable 011 can also be fixed in a fixed form such as an indenter, a figure eight-shaped aluminum sleeve, or an indenter with a hole in the middle of the screw. In this embodiment, each interlocking rope in the interlocking rope group 30 includes an S-shaped copper sleeve. Of course, in some other embodiments, each interlocking rope in the interlocking rope group 30 may include an S-shaped copper sleeve. , Or without S-shaped copper sleeve, it can be configured according to the actual situation.

In this embodiment, the entire boom adopts the same "spherical S"-shaped linkage rope to achieve linkage; with reference to Figure 11, the following describes the principle of the "spherical S"-shaped linkage rope:

(1) Coordinate description: The arm 11 and the arm 12 are connected by a ball pin pair 21, and the arm 12 and the arm 13 are connected by a ball pin pair 22. The outer spherical surface of the ball pin pair 21 (the first ball The cavity) is integrated with the arm 11, and the outer spherical surface (the first spherical cavity) of the ball pin 22 and the arm 12 are integrated. In the figure, O'and O" are the sphere centers of the two joints. The plane where the cable is currently located is the YZ plane, and both X'and X" are perpendicular to the outside of the paper, and the coordinate systems O'-X'Y'Z' and O"-X"Y"Z" are established respectively.

(2) Illustration of the reference point description: A ₁ , B ₄ are the cable fixing points; A ₂ , B ₂ are the center of the outer ring limit hole of the large spherical surface; A ₃ , B ₃ are the initial state of the boom (all corners are zero , That is, when the arm is a straight line), the tangent point between the cable and the outer spherical surface; A ₃ ', B ₃ 'is the tangent point between the cable and the outer spherical surface when the arm is linked (the corner is not zero); A ₄ , B ₁ It is the center of the cable step hole. Among them, in order to make the mechanical characteristics more reasonable and the linkage accuracy higher, in this embodiment, the linkage ropes A ₁ -A ₄ are symmetrical with B ₁ -B ₄ , and at the same time, A ₁ -A ₂ and A ₄ -A ₂ and B ₁ -B ₂ and B ₄ -B _{2 are} also arranged symmetrically.

(3) Description of the linkage principle of a single "spherical S"-shaped linkage rope: assuming that the arm 12 is stationary with respect to the inertial system, only consider that under the action of the single "spherical S"-shaped linkage rope as shown in the figure, the arm 11 will go around X 'The angle of rotation in the clockwise direction is α', the angle of rotation of the arm 12 in the counterclockwise direction around X" is α";

Obviously, in the process of linkage, the shape and length of the A ₁ A ₂ section of the cable are unchanged; under the action of the cable tension, the A ₃ A ₄ section of the cable is always connected to the large spherical surface of the arm 11 during the process of A ₃ becoming A ₃ ' Tangent, that is, when the arm 11 rotates through α', the increase in the length of the A ₁ A ₄ section of cable is the corresponding arc length of A ₃ A ₃ '. At the same time, the shape and length of the A ₄ B ₁ section of the cable are also unchanged under the premise of ignoring the change in cable length. Therefore, the decrease in the length of the B ₁ B ₄ cable length is equal to the corresponding arc length of A ₃ A ₃ '.

The analysis of the B ₁ B ₄ section of the cable shows that the shape and length of the B ₁ B ₂ section of the cable are unchanged; under the action of the cable tension, the B ₃ B ₄ section of the cable is always connected to the boom during the process of B ₃ becoming B ₃ ' The large spherical surface of 12 is tangent, that is, when the boom 12 rotates through α", the decrease in the length of the B ₁ B ₄ cable length is the corresponding arc length of B ₃ B ₃ '.

_{_{_{A 3 A '3 = B 3}}} B' 3

_{_{Where, A 3 A '3 = α'R}} , B 3 B' 3 = α "R can be obtained:

α′=α″

(4) Linkage decoupling: Take arm 11 and joint 21 as an example; when there is a rotation component around Y'in the rotation of the joint, the analysis of A ₁ A ₄ cables shows that the shape of A ₁ A ₂ cables is The length is not affected; the shape and length of the tangent point A ₃ 'will not be affected when sliding on the spherical surface, so the shape and length of the A ₂ A ₄ section of cable will not be affected; that is, the rotation component of the joint around Y'will not affect In this example, the linkage of rotation around the X'axis realizes the decoupling of rotation. That is to say, the combination of a flexible mechanical arm joint composed of a ball pin pair and a "spherical S"-shaped linkage rope realizes the constant curvature linkage with two degrees of freedom decoupling.

(5) Because the cable can only bear tensile force during transmission, at least 3 "spherical S"-shaped linkage ropes are required between each two joints to transfer the two degrees of freedom of rotation at the joints. In order to make the mechanical characteristics more reasonable, in this embodiment, three evenly distributed linkage ropes separated by 120° are used for linkage between the two joints. In some other embodiments, there may be more than three linkage ropes, and the distribution angle is not limited. It is only necessary to ensure that the linkage ropes do not interfere with each other.

In summary, when a certain number of small boom sections are used to form a whole boom section, the driving rope driven by the motor group passes through the outer ring of each boom and passes through to the end of the overall boom section; The rope head or other structure realizes the fixed connection; the number of driving ropes is at least 3; when the other end of the driving rope is pulled by the movable part, the whole arm section will move; at the same time, the linkage rope guarantees two degrees of freedom between each arm The equal angles on the upper part can realize the controllable boom configuration, the overall boom avoidance, path planning and other functions.

The flexible mechanical arm based on the ball pin pair in the preferred embodiment of the present invention has the following advantages:

(1) Compared with the shortcoming one in the first technical scheme, the structure of this scheme is more compact. Wire rope linkage occupies less space in the radial direction of the boom than gear linkage.

(2) Compared with the first and second disadvantages of the prior art solution, this technical solution can realize the linkage of two degrees of freedom between each joint. Boom movement planning is more flexible. In addition, compared with gear transmission, due to the inherent clearance of gear transmission, the linkage accuracy is affected. In the rope drive mechanism, by converting the working load of the arm section to the load of the linkage rope, setting a reasonable pre-tightening force can effectively ensure the linkage accuracy.

(3) In view of the first defect in the second solution of the prior art, the number of joint rods in the linkage arm section can only be 4, or a multiple of 4. In the solution of the present invention, a fully modular joint section is adopted, and the number of joint rods in the linkage arm section can be freely configured. The overall boom can be designed more flexibly according to the actual working conditions and the joint rotation angle required by path planning.

(4) The entire flexible arm is composed of a ball pin pair and a spherical s-shaped linkage rope, which is more concise than the prior art scheme 2. The number and types of components are reduced, the reliability is better, and the cost is lower.

(5) In the second solution of the prior art, during the linkage process of the remote linkage rope, the pitch and yaw angles will affect the shape of the remote linkage rope. Because there is relative movement between the remote linkage rope and the hose of the remote linkage rope, and there is a gap between the two. Therefore, during the linkage process of the remote linkage rope, the force on the linkage rope will fluctuate. Reduce the linkage effect. However, in this solution, the "spherical S"-shaped linkage rope will be adopted compared to the remote linkage rope of technical solution 2, and will not produce any shape change during the linkage movement. In addition, in the solution of the present invention, the modular design prevents the eccentric load phenomenon in the second technical solution between the cables of each joint segment and the cables on the opposite side of the center block during the movement. Therefore, the equal-angle linkage process is more reliable and stable.

(6) For the second technical solution, the remote linkage rope hose fixation mode occupies part of the radial space of the joint section. Inside the joint section, there are still four hoses running through. And because the shape of the remote linkage rope hose changes during the linkage process, more radial space is required. In the case of a relatively narrow operating space, since the end of the flexible arm usually has an execution tool or a camera, LED and other sensing devices. In the second solution of the prior art, the remote linkage rope occupies the radial space originally used for the passage of cables and optical fibers.

In the solution of the present invention, on the premise that the outer diameter of the arm rod is the same, the "spherical S"-shaped linkage rope is compared with the remote linkage rope of technical solution 2, and the radial space only needs twice the outer diameter of the hose. And in the process of linkage, because the "spherical S"-shaped linkage rope is always tightly attached to the arm under the cable tension, its shape will not change during the movement. Therefore, more space is left for the passage of cables, etc. in the boom.

(7) The "8"-shaped stainless steel rope in the second prior art solution requires two fixing points on the same side of the center block, so that the diameter of the disc on the center block is limited in design. In addition, in order to avoid interference between the cross block and the end of the arm rod during the movement of the arm rod, the existence of the cross block greatly reduces the utilization of the overall radial space of the arm rod.

However, in the solution of the present invention, a ball pin pair is used instead of the cross block to maximize the utilization of radial space while retaining two degrees of freedom of rotation. It also highlights the movement ability of the flexible robotic arm in a small space.

(8) In addition, the solution of the present invention is more convenient to assemble than the second solution of the prior art. In the second solution of the prior art, the small s linkage rope is assembled and pre-tightened on the cross block at the rotating joint, and the operating space is limited by the cross block and the arm rod, which is very inconvenient. In the solution of the present invention, there is only one spherical s-shaped linkage rope, and its assembly and pre-tightening direction is the direction of the arm axis with relatively open space, which is convenient.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art to which the present invention belongs, without departing from the concept of the present invention, several equivalent substitutions or obvious modifications can be made, and the same performance or use should be regarded as belonging to the protection scope of the present invention.

Claims

A flexible mechanical arm based on a ball pin pair, which is characterized in that it comprises a multi-segment arm rod, a multi-group linkage rope group and a plurality of driving ropes. The multi-segment arm rods are connected end to end in sequence, and each of the two adjacent segments The arm rods are connected by a ball pin pair, and each group of the linkage rope group corresponds to each section of the arm rod with the ball pin pair connected at both ends, and each group of the linkage rope group includes multiple linkage ropes, A plurality of said interlocking ropes in each group of interlocking ropes respectively bypass the corresponding ball pin pair of the first end of the arm, the corresponding arm and the corresponding The ball pin pair at the second end of the arm rod realizes linkage, and each of the linkage ropes is S-shaped on the corresponding arm rod; a plurality of the driving ropes respectively pass through a plurality of sections connected end to end in sequence. The arm rod is used to realize the driving of multiple sections of the arm rod.
The flexible mechanical arm according to claim 1, wherein the ball pin pair includes a first ball cavity, a second ball cavity and a pin shaft, and the first ball cavity is fixedly connected to the arm rod. The second spherical cavity is arranged in the first spherical cavity, and the pin shaft passes through the first spherical cavity and the second spherical cavity in order to make the first The degree of freedom of rotation of the spherical cavity and the second spherical cavity in the axial direction around the arm rod is constrained and can be relatively rotated in two directions perpendicular to the axial direction of the arm rod, wherein The second ball cavity can be sleeved on the second end of the adjacent arm rod and connected with the second end of the adjacent arm rod through a key to form the ball pin pair.
The flexible mechanical arm according to claim 2, wherein the first spherical cavity or the second spherical cavity is provided with a sliding groove, and the length of the sliding groove is along the length of the arm. It is arranged in the axial direction, wherein when a sliding groove is provided on the first spherical cavity, the pin is threaded or interference fit with the second spherical cavity, and the second spherical cavity is provided with When sliding grooves, the pin and the first spherical cavity are threaded or interference fit.
The flexible mechanical arm according to claim 2, wherein each of the ball pin pairs includes two pin shafts, and the two pin shafts respectively pass through the first spherical cavity and the second A spherical cavity, wherein two of the pins are symmetrically arranged at two ends of the first spherical cavity and the second spherical cavity, and the axes of the two pin shafts are collinear.
The flexible mechanical arm according to claim 2, wherein the second spherical cavity is composed of at least two spherical cavity body parts, wherein at least two of the spherical cavity body parts are spliced with each other to form the second ball Cavity.
The flexible mechanical arm according to claim 2, wherein a plurality of key grooves are provided in the second spherical cavity, a plurality of protruding keys are provided on the second end of the arm rod, and a plurality of The keys can be inserted into the plurality of key grooves respectively; and a stop part is also provided at the second end of the arm rod, and the end of the second spherical cavity and/or the first spherical cavity The part is provided with a thrust surface, and the stop part is provided on the tail part of the plurality of keys to stop the second spherical cavity and/or the first spherical cavity in the axial direction of the arm rod The thrust surface at the end of the body.
The flexible mechanical arm according to claim 1, wherein the two ends of the plurality of linkage ropes in each linkage rope group are respectively fixedly connected to two sections connected to the two ends of the corresponding arm rod. On the arm.
The flexible mechanical arm according to claim 1, wherein each group of linkage ropes includes at least three of the linkage ropes, and the three linkage ropes are respectively distributed on the circumference of the corresponding arm rod without interfering with each other .
The flexible mechanical arm according to claim 1, wherein each of the two ends of the arm rod is provided with a first flange, and the first flange is provided with a plurality of first holes and a plurality of second Two holes, the ball pin pair is provided with a second flange, the second flange is provided with a plurality of third holes, the first hole, the second hole and the third hole are respectively along Set in the axial direction of the arm rod, the first end of each linkage rope is fixedly connected to the first protrusion of the second end of the arm rod connected to the first end of the corresponding arm rod In the first hole of the rim, the second end is fixedly connected to the first hole of the first flange of the first end of the arm rod connected to the corresponding second end of the arm rod , The first end to the second end of each of the linkage ropes sequentially pass through the third hole of the second flange on the ball pin pair at the first end of the corresponding arm rod , The corresponding second hole on the first flange of the first end of the arm rod, and the second hole on the first flange of the corresponding second end of the arm rod Hole and the third hole of the second flange on the ball pin pair at the second end of the corresponding arm rod; further, each of the linkage ropes is on the corresponding arm rod The second hole on the first flange of the first end and the corresponding second hole on the first flange of the second end of the arm rod are in an S shape; Ground, each of the linkage ropes is also provided with an S-shaped copper sleeve corresponding to the second hole and the second hole on the first flange of the first end of the corresponding arm rod. On the linkage rope between the second holes on the first flange of the corresponding second end of the arm rod, and the second hole is a stepped hole to fix the S-shaped copper sleeve The ends.
The flexible mechanical arm according to claim 9, wherein the first end of each linkage rope corresponds to the second end on the first flange of the first end of the arm rod. Between the holes and between the second end and the second hole on the first flange of the corresponding second end of the arm rod are arranged along the axial direction of the arm rod; further, At least one threaded hole is correspondingly provided on the first hole, and the threaded hole is arranged perpendicular to the first hole so that at least one screw can respectively penetrate into the at least one threaded hole to fix the first of the linkage rope One end or second end.