Four-rope-driven snake-shaped arm robot

Abstract

The invention relates to the field of robots, in particular to a four-rope-driven snakelike arm robot which comprises an arm body and a driving part, the arm body is formed by sequentially and movably connecting a plurality of connecting rods, every two adjacent connecting rods are connected through a cross shaft to form a joint, and every two adjacent connecting rods freely swing in the up-down direction and the left-right direction through the corresponding cross shaft. The driving part comprises a plurality of driving units, a driving box for loading the driving units and a fixing rod arranged at the front end of the driving box, and the first joint in the arm body is connected with the fixing rod; the four-rope-driven snake-shaped arm robot structure comprises a plurality of connecting rods, each connecting rod is in linkage with two driving units at the same time, each driving unit is provided with two traction ends, the two traction ends are connected to the two opposite ends of the corresponding connecting rod respectively, and the two traction ends move oppositely to drive the corresponding connecting rods to swing up and down or left and right. The number of motors is equal to the number of joint degrees of freedom, and driving redundancy is avoided.

Description

Technical Field

[0001] The invention relates to the field of robots, in particular to a four-rope driven snake-arm robot. Background Art

[0002] When the serpentine arm is used in confined spaces or special working spaces, in order to avoid environmental interference with the drive and reduce the mass of the serpentine arm, it is generally chosen to place the drive device at the rear and use the traction line to drive the serpentine arm to move. Existing rope-driven serpentine arms generally use three-rope drive. Each traction line corresponds to a motor lead screw slider to achieve rope length changes. However, the three rope length variables correspond to two joint variables, and there is redundant drive. At the same time, the control cable of the end joint needs to pass through the wire hole of the front joint. There is friction between the traction line and the front wire hole, and there is serious coupling between the rope length variables. Summary of the invention

[0003] In order to overcome the above-mentioned shortcomings, the present invention aims to provide a technical solution that can solve the above-mentioned problems.

[0004] A four-rope driven serpentine arm robot comprises an arm body and a driving part, wherein the arm body is formed by a plurality of connecting rods movably connected in sequence, two adjacent connecting rods are connected by a cross shaft to form a joint, and the two adjacent connecting rods are free to swing in the up-down and left-right directions through the cross shaft, the driving part comprises a plurality of driving units, a driving box loaded with the driving units and a fixed rod arranged at the front end of the driving box, and the first joint in the arm body is connected to the fixed rod; each connecting rod is linked to two driving units at the same time, each driving unit is provided with two traction ends, and the two traction ends are respectively connected to the opposite ends of the connecting rod, and the two traction ends are driven to move in opposite directions to drive the corresponding connecting rod to swing in the up-down and left-right directions.

[0005] As a further solution of the present invention: the driving unit includes a driving assembly, a main screw slider module, a secondary screw slider module, a main rope head fixing seat, a secondary rope head fixing seat, a main traction line, a secondary traction line and a fixed plate, the main screw slider module and the secondary screw slider module are arranged in parallel on the fixed plate, the main screw slider module and the secondary screw slider module are both transmission connected to the driving assembly, the main rope head fixing seat is arranged on the slider of the main screw slider module, the secondary rope head fixing seat is arranged on the slider of the secondary screw slider module, the starting ends of the main traction line and the secondary traction line are respectively fixed on the main rope head fixing seat and the secondary rope head fixing seat, and the ends of the main traction line and the secondary traction line are respectively connected to the opposite ends of a connecting rod.

[0006] As a further solution of the present invention: the driving assembly includes a driving motor, a motor support frame, a driving gear and a driven gear, the driving motor is arranged on the motor support frame, the output shaft of the driving motor is connected to the driving gear, the driving gear and the driven gear are meshed with each other, the module and the number of teeth of the driving gear and the driven gear are equal, the driving gear is connected to the screw shaft of the main screw slider module, and the driven gear is connected to the screw shaft of the auxiliary screw slider module.

[0007] As a further solution of the present invention: the connecting rod includes a sleeve and a flange fixed on the end of the sleeve, and strip grooves for the main traction line and the auxiliary traction line to pass through are evenly opened along the axial direction of the tube wall of the sleeve, and corresponding wire holes are opened at positions corresponding to the strip grooves on the flange, and ear plates pivotally connected to a pair of relative pivots in the cross axis are formed on the end face of the flange.

[0008] As a further solution of the present invention: a plurality of threaded holes are provided on the end face of the sleeve, a plurality of fixing holes corresponding to the threaded holes are provided on the flange, and the flange is fixed to the end face of the sleeve by screws passing through the fixing holes and threadedly connected with the threaded holes.

[0009] As a further solution of the present invention: a plurality of springs are connected between the flanges of two adjacent connecting rods, and the axis of the spring coincides with the axis of the wire hole.

[0010] As a further solution of the present invention: the main traction line and the auxiliary traction line are both covered with wire sleeves.

[0011] As a further solution of the present invention: the main rope end fixing seat, the auxiliary rope end fixing seat and the connecting rod are all provided with rope end fixers for fixing the main traction line and the auxiliary traction line.

[0012] As a further solution of the present invention: a plurality of layer plates for placing the drive units are arranged at intervals in the drive box, and a plurality of through holes for the traction ends of the drive units to pass through are opened at the front end of the drive box.

[0013] As a further solution of the present invention: the number of drive units is twice the number of joints.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. By setting up a drive unit with two traction ends, one motor can control two traction lines. The number of motors is equal to the number of joint degrees of freedom, thus avoiding drive redundancy.

[0016] 2. By setting the strip groove and the wire sleeve, the traction wire of the connecting rod at the end of the arm does not need to pass through the wire hole of the front connecting rod. The variable of each joint is only determined by the length of the traction wire of its corresponding connecting rod, and has nothing to do with the traction wire of other connecting rods, thus avoiding the coupling between the rope length variables and reducing friction.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 This is the structural diagram of the four-rope driven snake-arm robot;

[0020] Figure 2 This is a structural diagram of the joint part;

[0021] Figure 3 This is a partial structural diagram of the drive box;

[0022] Figure 4 This is a partial structural diagram of the drive component;

[0023] Figure 5 It is the structural diagram of the connecting rod part;

[0024] Figure 6 This is the line hole spacing analysis diagram of the two flanges when the joint rotates;

[0025] Figure 7 It is the relationship diagram between joint angle and wire hole spacing;

[0026] Figure 8 This is another relationship diagram between joint angle and wire hole spacing.

[0027] In the figure: 1, driving part, 2, arm body, 11, driving unit, 12, driving box, 13, layer plate, 14, through hole, 15, fixing rod, 21, connecting rod, 22, cross shaft, 23, spring, 24, wire sleeve, 25, rope head fixer, 26, joint, 111, driving assembly, 112, main screw rod slider module, 113, auxiliary screw rod slider module, 114, main rope head fixing seat, 115, auxiliary rope head fixing seat, 116, main traction line, 117, auxiliary traction line, 118, fixing plate, 211, sleeve, 212, flange, 213, strip groove, 214, wire hole, 215, ear plate, 216, threaded hole, 217, fixing hole, 1111, driving motor, 1112, motor support frame, 1113, driving gear, 1114, driven gear. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figures 1 to 5 In the embodiment of the present invention, a four-cable driven snake-arm robot includes an arm body 2 and a driving part 1. The arm body 2 is formed by a plurality of connecting rods 21 movably connected in sequence. Two adjacent connecting rods 21 are connected by a cross shaft 22 to form a joint 26. The two adjacent connecting rods 21 are connected by the cross shaft 22 to achieve free swing in the up and down and left and right directions. The driving part 1 includes a plurality of driving units 11, a driving box 12 loaded with the driving units 11, and a fixed rod 15 arranged at the front end of the driving box 12. The first joint 26 in the arm body 2 is connected to the fixed rod 15; each connecting rod 21 is connected to two driving units at the same time. The units 11 are linked, and each driving unit 11 is provided with two traction ends, which are respectively connected to the opposite ends of the connecting rod 21. The two traction ends move in opposite directions to drive the corresponding connecting rod 21 to swing up and down or left and right. The two adjacent connecting rods 21 of the arm body 2 have two degrees of freedom in the up and down and left and right directions. The last connecting rod 21 of the arm body 2 is used to connect with the working part. During operation, each connecting rod 21 of the arm body 2 is driven by two driving units 11, so that the arm body 2 can bend and swing in confined space and special working space.

[0030] The driving unit 11 includes a driving component 111, a main screw slider module 112, an auxiliary screw slider module 113, a main rope head fixing seat 114, an auxiliary rope head fixing seat 115, a main traction line 116, an auxiliary traction line 117 and a fixing plate 118. The main screw slider module 112 and the auxiliary screw slider module 113 are arranged in parallel on the fixing plate 118. The main screw slider module 112 and the auxiliary screw slider module 113 are both transmission-connected to the driving component 111. The main rope head fixing seat 114 is arranged on the slider of the main screw slider module 112, and the auxiliary rope head fixing seat 115 is arranged on the slider of the auxiliary screw slider module 113. The starting ends of the main traction line 116 and the auxiliary traction line 117 are respectively fixed on the main rope head fixing seat 114 and the auxiliary rope head fixing seat 115, and the ends of the main traction line 116 and the auxiliary traction line 117 are respectively connected to the opposite ends of a connecting rod 21.

[0031] The driving assembly 111 includes a driving motor 1111, a motor support frame 1112, a driving gear 1113 and a driven gear 1114. The driving motor 1111 is arranged on the motor support frame 1112. The output shaft of the driving motor 1111 is connected to the driving gear 1113. The driving gear 1113 and the driven gear 1114 are meshed with each other. The module and the number of teeth of the driving gear 1113 and the driven gear 1114 are equal. The driving gear 1113 is connected to the screw shaft of the main screw slider module 112, and the driven gear 1114 is connected to the screw shaft of the auxiliary screw slider module 113.

[0032] It should be noted that when the driving motor 1111 rotates an angle θ, the driving gear 1113 rotates an angle θ, and the driven gear 1114 rotates an angle -θ. At this time, the slider of the main screw slider module 112 moves a distance L, and the slider of the auxiliary screw slider module 113 moves a distance -L. According to the matching relationship, the main rope head fixing seat 114 follows the movement of the slider on the main screw slider module 112, driving the main traction line 116 to move L at the driving connecting rod 21. The auxiliary rope head fixing seat 115 follows the movement of the slider on the auxiliary screw slider module 113, driving the auxiliary traction line 117 to move -L at the driving connecting rod 21. That is, the driving motor 1111 can control the movement of the main traction line 116 and the auxiliary traction line 117 at the same time.

[0033] The connecting rod 21 includes a sleeve 211 and a flange 212 fixed at the end of the sleeve 211. Strip grooves 213 for the main traction line 116 and the auxiliary traction line 117 to pass through are evenly opened along the axial direction of the tube wall of the sleeve 211. Corresponding wire holes 214 are opened at positions corresponding to the strip grooves 213 on the flange 212. Ear plates 215 pivotally connected to a pair of relative pivots in the cross shaft 22 are formed on the end surface of the flange 212. Two adjacent connecting rods 21 are connected to the two ear plates 215 through the cross shaft 22 to achieve double-degree-of-freedom rotation.

[0034] A plurality of threaded holes 216 are formed on the end surface of the sleeve 211 , and a plurality of fixing holes 217 corresponding to the threaded holes 216 are formed on the flange 212 . The flange 212 is fixed to the end surface of the sleeve 211 by screws passing through the fixing holes 217 and threadedly connected to the threaded holes 216 .

[0035] A plurality of springs 23 are connected between the flanges 212 of two adjacent connecting rods 21. The axis of the spring 23 coincides with the axis of the wire hole 214. The spring 23 can be wrapped around the outside of the main traction line 116 and the auxiliary traction line 117 to ensure the stability of the movement of the connecting rod 21, so that the connecting rod 21 can reach the specified position and remain stable.

[0036] The main traction line 116 and the auxiliary traction line 117 are both covered with a wire sleeve 24 to achieve flexible and bendable guidance of the main traction line 116 and the auxiliary traction line 117. The wire sleeve 24 can adopt a bicycle brake wire sleeve structure.

[0037] The main rope end fixing seat 114 , the auxiliary rope end fixing seat 115 , and the connecting rod 21 are all provided with rope end fixers 25 for fixing the main traction line 116 and the auxiliary traction line 117 .

[0038] A plurality of layer plates 13 for placing the drive units 11 are arranged at intervals in the drive box 12 , and a plurality of through holes 14 for the traction ends of the drive units 11 to pass through are opened at the front end of the drive box 12 .

[0039] Each connecting rod 21 requires two driving units 11 to drive it. The number of driving units 11 is twice the number of joints 26. For example, if there are five joints 26, the number of driving units 11 is 5*2=10.

[0040] It is also necessary to note that, please refer to Figures 6 to 8 , the main traction line 116 and the auxiliary traction line 117 controlled by the same driving motor 1111 are distributed at 180 degrees. Since the main traction line 116 and the auxiliary traction line 117 are initially installed, the total length of the traction line is a fixed value. That is, when the main traction line 116 moves L at the driving unit 11 and the auxiliary traction line 117 moves -L at the driving unit 11, the main traction line 116 will move -L at the joint 26, and the auxiliary traction line 117 will move L at the joint 26.

[0041] Figure 6 2 is an analysis diagram of the spacing between the wire holes 214 of the two flanges 212 when the joint 26 rotates. The dotted line in the figure indicates the position of the flange 212 before the rotation, and the solid line indicates the position of the flange 212 after the rotation. At the joint 26, the initial spacing between the wire holes 214 is l 1 , the diameter of the wire hole 214 is d. Then when the joint 26 rotates q around the rotation center, according to the geometric relationship, 2α+q=180°, then The angles between the line connecting the wire holes 214 on both sides and the vertical direction are and According to the above angle relationship, we can get:

[0042] The spacing of the wire holes 214 after the left side rotation is:

[0043]

[0044] The spacing between the wire holes 214 after the right side rotation is:

[0045]

[0046] According to the above expression of the spacing between the left and right wire holes 214 after the change, the changes in the spacing between the left and right wire holes 214 are respectively because Then |Δl 左 |≥|Δl 右When the joint 26 rotates, the shortening amount of the distance between the left wire holes 214 is greater than the elongation amount of the distance between the right wire holes 214.

[0047] As can be seen from the above, the main traction line 116 moves -L at the joint 26, and the auxiliary traction line 117 moves L at the joint 26. Let Δl 左 =-L, then Δl 右 <L. At this time, the main traction line 116 is in a tension state, and the auxiliary traction line 117 is in a relaxed state. That is, by using the drive motor 1111 to control the rope length variable of the main traction line 116, the auxiliary traction line 117 remains relaxed and there is no risk of breakage.

[0048] Since only one side is in tension when the drive motor 1111 controls the main traction line 116 and the auxiliary traction line 117, in order to ensure the stability of the movement of the connecting rod 21, the spring 23 is wrapped outside the main traction line 116 and the auxiliary traction line 117, so that the connecting rod 21 can reach the specified position and remain stable.

[0049] Figure 7 For the joint angle q 1 = 0°, when q 2 changes from 0° to the limit angle of 30°, the change of the distance between the wire holes 214 of the main traction line 116 and the auxiliary traction line 117. It can be seen from the figure that the distance between the wire holes 214 of the main traction line 116 increases at the joint 26, and the distance between the wire holes 214 of the auxiliary traction line 117 decreases at the joint 26, and the distance between the wire holes 214 changes continuously. Then, by controlling the rope length variable of the auxiliary traction line 117 to be equal to the distance between the wire holes 214 of the auxiliary traction line 117, the position control of the connecting rod 21 can be realized. At this time, the main traction line 116 is in tension and the auxiliary traction line 117 is in a relaxed state.

[0050] Figure 8 For the joint angle q 1 = 30°, when q 2 changes from 0° to the limit angle of 30°, the change of the distance between the wire holes 214 of the main traction line 116 and the auxiliary traction line 117. When q 1 = 30°, q 2 = 0°, the distance between the wire holes 214 of the main traction line 116 at the joint 26 is -12.6845 mm, and the distance between the wire holes 214 of the auxiliary traction line 117 at the joint 26 is 9.2771 mm. Just control the rope length variable of the main traction line 116 to be equal to the distance between the wire holes 214 of the main traction line 116, and the position control of the connecting rod 21 can be realized. At this time, the main traction line 116 is in tension and the auxiliary traction line 117 is in a relaxed state. It can be seen from the figure that q 2=22.5°, the distance between the two flanges 212 is less than 0. Since the distance between the wire holes 214 and the length of the traction wire are continuously changing, according to the state of the previous two traction wires, the rope length variable of the main traction wire 116 is continued to be equal to the distance variable of the wire holes 214, so that the joint 26 can move according to the specified trajectory. At this time, the state of the traction wire is still that the main traction wire 116 is pulled, and the auxiliary traction wire 117 is in a relaxed state.

[0051] In summary, in the four-rope driven serpentine arm robot structure, the number of motors is equal to the number of degrees of freedom of the joint 26, avoiding drive redundancy. The control cable of the end link 21 does not need to pass through the wire hole 214 of the front link 21, and each joint variable is only determined by the traction wire length of its corresponding link 21, and has nothing to do with the traction wires of other links 21, avoiding coupling between rope length variables.

[0052] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A four-cable driven snake-arm robot, characterized in that: include: The arm body is composed of a plurality of connecting rods connected in sequence. A cross axis is used to connect two adjacent connecting rods to form a joint. The cross axis is used to realize free swinging in the up and down and left and right directions between the two adjacent connecting rods. The driving part includes a plurality of driving units, a driving box for loading the driving units, and a fixing rod arranged at the front end of the driving box, and the first joint in the arm body is connected to the fixing rod; Each connecting rod is linked to two driving units at the same time. Each driving unit is provided with two traction ends, which are respectively connected to the opposite ends of the connecting rod. The two traction ends move in opposite directions to drive the corresponding connecting rod to swing up and down or left and right.

2. A four-cable driven snake-arm robot according to claim 1, characterized in that: The driving unit includes a driving assembly, a main screw slider module, an auxiliary screw slider module, a main rope head fixing seat, an auxiliary rope head fixing seat, a main traction line, an auxiliary traction line and a fixing plate. The main screw slider module and the auxiliary screw slider module are arranged in parallel on the fixing plate. The main screw slider module and the auxiliary screw slider module are both transmission-connected to the driving assembly. The main rope head fixing seat is arranged on the slider of the main screw slider module, and the auxiliary rope head fixing seat is arranged on the slider of the auxiliary screw slider module. The starting ends of the main traction line and the auxiliary traction line are respectively fixed on the main rope head fixing seat and the auxiliary rope head fixing seat, and the ends of the main traction line and the auxiliary traction line are respectively connected to the opposite ends of a connecting rod.

3. A four-cable driven snake-arm robot according to claim 2, characterized in that: The driving assembly includes a driving motor, a motor support frame, a driving gear and a driven gear. The driving motor is arranged on the motor support frame. The output shaft of the driving motor is connected to the driving gear. The driving gear and the driven gear are meshed with each other. The module and the number of teeth of the driving gear and the driven gear are equal. The driving gear is connected to the screw shaft of the main screw slider module, and the driven gear is connected to the screw shaft of the auxiliary screw slider module.

4. A four-cable driven snake-arm robot according to claim 3, characterized in that: The connecting rod includes a sleeve and a flange fixed on the end of the sleeve. Strip grooves for the main traction line and the auxiliary traction line to pass through are evenly opened along the axial direction of the tube wall of the sleeve. Corresponding wire holes are opened at positions corresponding to the strip grooves on the flange. Ear plates pivotally connected to a pair of relative pivots in the cross axis are formed on the end surface of the flange.

5. A four-cable driven snake-arm robot according to claim 4, characterized in that: The end surface of the sleeve is provided with a plurality of threaded holes, and the flange is provided with a plurality of fixing holes corresponding to the threaded holes. The flange is fixed on the end surface of the sleeve by screws passing through the fixing holes and threadedly connected with the threaded holes.

6. A four-cable driven snake-arm robot according to claim 4, characterized in that: A plurality of springs are connected between the flanges of two adjacent connecting rods, and the axes of the springs coincide with the axes of the wire holes.

7. The four-cable driven snake-arm robot according to claim 2, characterized in that: The main traction line and the auxiliary traction line are both covered with wire sleeves.

8. The four-cable driven snake-arm robot according to claim 2, characterized in that: The main rope head fixing seat, the auxiliary rope head fixing seat and the connecting rod are all provided with rope head fixers for fixing the main traction line and the auxiliary traction line.

9. The four-cable driven snake-arm robot according to claim 1, characterized in that: A plurality of layer plates for placing the driving units are arranged at intervals in the driving box, and a plurality of through holes for the traction ends of the driving units to pass through are opened at the front end of the driving box.

10. The four-cable driven snake-arm robot according to claim 1, characterized in that: The number of drive units is twice the number of joints.

Images