Quaternion joint snake robot based on gear linkage

Abstract

The application discloses a four-element joint snake-shaped mechanical arm based on gear linkage, which comprises a driving part and a mechanical arm end part; the mechanical arm end part is based on a four-element joint, and a gear linkage joint capable of bending at equal angles is formed by adding gear linkage between two joints; the driving part is driven by a motor to rotate a lead screw, so that a lead screw nut moves along the axial direction of the lead screw; driving ropes are placed on the left and right sides of the lead screw nut respectively; one of the ropes is changed in direction through a fixed pulley and then changes direction with the other rope, so that the two ropes point to the same direction, but the movement directions of the two ropes are opposite and the change amounts are the same with the rotation of the motor; the single motor can control single degree of freedom by combining the characteristics that the change amounts of the driving part and the four-element joint on the two sides are the same; the driving part and the gear linkage joint are modularly combined to form the whole snake-shaped mechanical arm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of robot technology, and more particularly to the field of rope-driven snake-shaped mechanical arm. BACKGROUND

[0002] Robot is a broad concept, and the general impression of robot is a rigid robot with fixed shape. In fact, robot also includes flexible snake-shaped robot. The snake-shaped robot is designed by imitating the movement of animal snake or the movement of elephant trunk in biological world. The robot can bend in large angle in real time and change the shape of structure, so that it can better adapt to various environments and complete complex tasks, and is more flexible than traditional rigid robot. The snake-shaped robot has good bending characteristics and can be generally used for operation in narrow space.

[0003] The existing snake-shaped robot generally has the structure that a motor is placed at the joint for direct control or a universal joint structure is arranged at the joint for rope-driven control. The existing snake-shaped robot has problems in different degrees. The existing snake-shaped robot with the structure that a motor is placed at the joint for direct control has large volume and complex electrical circuit, and the structure is more complex due to multi-degree-of-freedom movement. The existing snake-shaped robot with the structure that a universal joint is arranged at the joint for rope-driven control has insufficient activity freedom, and the number of required motors is large, which increases the manufacturing cost and control difficulty. SUMMARY

[0004] The present application is to avoid the problems of the prior art, and provides a four-element number joint snake-shaped robot based on gear linkage, which realizes controllable linkage bending at the middle part of the gear linkage joint at the arm end, and increases the bending angle of the arm end. The four-element number joint is used at the arm end, so that single motor controls single degree of freedom, thereby reducing the number of motors.

[0005] The present application adopts the following technical scheme to achieve the object:

[0006] The four-element number joint snake-shaped robot based on gear linkage has the following characteristics: the snake-shaped robot is composed of an arm end, a driving box and a driving rope.

[0007] The arm end is composed of a plurality of gear linkage joint modules, and each gear linkage joint is composed of a four-element number joint. The four-element number joint is mainly composed of three connecting rods which are mutually constrained, and the bending of the joint is realized by simulating the rolling of two hemispherical surfaces. The two four-element number joints are meshed by gears, so that the six connecting rods in the two four-element number joints are mutually constrained to realize the equal-angle bending of the two four-element number joints. The plurality of gear linkage joint modules are modularized to form the arm end.

[0008] The drive box consists of a motor connected to a lead screw. The motor drives the lead screw to rotate, and a linear optical axis determines the direction of movement of the lead screw nut, enabling the linear reciprocating motion of the nut slider seat. Two drive ropes pointing in opposite directions are connected to the nut slider seat. The drive rope pointing towards the motor changes direction through a fixed pulley, so that the two drive ropes point in the same direction, ensuring that the elongation (shortening) of one drive rope is equal to the shortening (elongation) of the other drive rope. The drive ropes pull the joint to bend. The drive box, composed of multiple sets of motors, lead screws, linear optical axes, and pulleys, pulls multiple drive ropes to achieve the bending motion of the entire robotic arm.

[0009] The quaternion-jointed serpentine robotic arm based on gear linkage of this invention is also characterized by the following: the end-arm structure of the robotic arm includes:

[0010] The quaternion joint is formed by connecting an inter-articular plate to a connecting block via a pin. The connecting block can rotate via the pin and is then connected to a connecting rod via a pin. Three connecting rods are connected to the inter-articular plate at 120° intervals around the circumference. The other end of the connecting rod is connected to a gear connecting block. The gear connecting block is connected to a gear-bearing plate at a position symmetrical to the connecting block. After the three connecting rods are fully connected, they constrain each other to form a quaternion joint.

[0011] The gear linkage joint consists of two quaternion joints placed symmetrically. The quaternion joints are fixed to the joint connectors by screws. The gear connecting blocks in the two quaternion joints mesh with each other, so that the six connecting rods are mutually constrained and the two quaternion joints bend at the same angle.

[0012] The end of the robotic arm is composed of five gear-linked joints, and each pair of gear-linked joints is connected and fixed to a joint connector by screws.

[0013] The quaternion-jointed serpentine robotic arm based on gear linkage of this invention is also characterized by the following: the drive box structure includes:

[0014] The motor is connected to the lead screw via a coupling. The left end of the lead screw is fixed to the lead screw fixing plate via a lead screw fixing seat, and the right side of the lead screw is placed on the lead screw support plate via a lead screw support seat. A fixed pulley is placed on the upper side of the lead screw fixing seat on the lead screw fixing plate, and an optical axis support seat for fixing the linear optical axis is placed on the lower side of the lead screw fixing seat. The lower side of the nut slider seat is connected to the optical axis slider, and the upper side of the nut slider seat is provided with a threaded hole for fixing a self-locking wire lock device, which can be connected to the drive rope. Between the lead screw fixing plate and the lead screw support plate, there are two rows and five columns each, totaling ten sets of motor, lead screw, linear optical axis, and pulley combinations. The lead screw fixing plate and the lead screw support plate are fixedly connected by four box positioning plates to form the box shell frame. The lead screw fixing plate and the lead screw support plate are fixed to the box positioning plates by L-shaped connectors. The lead screw support plate has threaded holes for connecting conduit connectors at the positions corresponding to the pulley and the nut slider seat.

[0015] The quaternion joint snake-shaped robotic arm based on gear linkage of the present invention is characterized by the fact that the total length of the two ropes at the symmetrical rope holes remains unchanged, that is, when the quaternion joint is bent, the elongation of one rope at the symmetrical position is equal to the shortening of the other rope; the gear linkage joint also has this characteristic.

[0016] The quaternion joint snake-like robotic arm based on gear linkage of this invention is characterized by the following: the joint connector has three protruding structures with threaded holes inside, which are connected and fixed to the joint plate by screws, and the distance between the two side plates of the joint connector is increased, so as to connect with the quaternion joint; 20 rope holes are distributed around the outer circumference of the joint connector, and the end face of the rope hole is rounded to reduce the friction between the rope and the rope hole; the outer surface of the joint connector is set in a concave shape to reduce the rope friction and reduce the difficulty of processing the small rope holes.

[0017] The quaternion joint snake-shaped robotic arm based on gear linkage of the present invention is characterized in that: a root joint connector is provided at the root of the robotic arm end, the root joint connector is provided with a rope hole for connecting to a conduit connector, and the conduit connector on the root joint connector is connected to a wire conduit corresponding to the conduit connector on the lead screw support plate.

[0018] The quaternion joint snake-shaped robotic arm based on gear linkage of the present invention is also characterized in that: the arm end of the robotic arm is connected to the drive box through a box-arm connector, the left end of the box-arm connector is embedded in the lead screw support plate and fixed by screws; the right end of the box-arm connector is connected to the root joint connector.

[0019] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0020] 1. The robotic arm of this invention is driven by a rope, with the joints and drive box designed separately. The joints and drive box are modularly composed, and multiple parts can be interchanged, which facilitates the production and assembly of parts.

[0021] 2. The robotic arm of this invention uses quaternion joints as the main body, without the arm rod design in the traditional snake-shaped robotic arm, and the entire arm end can be bent; with the addition of gear linkage, the bending angle is increased without increasing the number of drive ropes, making the bending of the robotic arm more in line with the serpentine movement of a snake.

[0022] 3. This invention utilizes the characteristic that the sum of the lengths of the two ropes at the symmetrical rope holes of the quaternion joint remains unchanged. Combined with the design of adding a pulley above the lead screw in the drive box, it can achieve single motor control of a single degree of freedom, reducing the number of drive motors, lowering production costs, and also reducing the difficulty of equipment control. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the internal structure of the drive box in this invention;

[0025] Figure 3 This is a schematic diagram of the gear linkage joint principle structure in this invention;

[0026] Figure 4 (a) is a schematic diagram of the unbent drive rope length of the gear linkage joint in this invention;

[0027] Figure 4 (b) is a schematic diagram of the change in the length of the bending drive rope of the gear linkage joint in this invention;

[0028] Figure 5 This is a schematic diagram of the quaternion joint structure in this invention;

[0029] Figure 6 This is a schematic diagram of the interarticular plate installation in this invention;

[0030] Figure 7 This is a schematic diagram of the connecting wire conduit for the root joint connector in this invention;

[0031] Figure 8 This is a schematic diagram of the drive housing connecting to the joint arm end in this invention;

[0032] The diagram labels are as follows: 1. Robotic arm end cap; 2. Drive box; 3. Drive rope; 11. Gear linkage joint; 12. Quaternion joint; 101. Joint plate; 102. Pin; 103. Connecting block; 104. Linkage rod; 105. Gear connecting block; 106. Plate with gear hole; 107. Screw; 108. Joint connector; 109. Root joint connector; 110. Box arm connector; 201. Motor; 202. Coupling; 203. Lead screw; 204. Lead screw mounting base; 205. Lead screw mounting plate. 206 Screw support seat, 207 Screw support plate, 208 Pulley, 209 Linear optical axis, 210 Optical axis support seat, 211 Nut slider seat, 212 Optical axis slider, 213 Wire lock, 214 Box positioning plate, 215 L-shaped connector, 216 Conduit connector, 217 Screw nut, 218 Wire conduit, 301 Lower left rope length, 302 Upper left rope length, 303 Upper ball center distance, 304 Upper right rope length, 305 Lower right rope length, 306 Lower ball center distance. Detailed Implementation

[0033] See Figure 1 , Figure 2 and Figure 3 In this embodiment, the quaternion joint snake-shaped robotic arm based on gear linkage consists of the robotic arm end 1, the drive box 2, and the drive rope 3.

[0034] The robotic arm end 1 is modularly composed of multiple gear-linked joints 11, and each gear-linked joint 11 is composed of quaternion joints 12. The quaternion joint 12 is mainly constrained by three connecting rods 104. By simulating the rolling of two hemispheres, the bending of the joint is achieved. The two quaternion joints 12 are connected by gear meshing, so that the six connecting rods 104 in the two quaternion joints 12 are mutually constrained, so as to achieve the bending of the two quaternion joints 12 at the same angle. The robotic arm end 1 is modularly composed of multiple gear-linked joints 11.

[0035] The drive box 2 consists of a motor 201 connected to a lead screw 203. The motor 201 drives the lead screw 203 to rotate, and the linear optical axis 209 determines the direction of movement of the lead screw nut 217, realizing the linear reciprocating motion of the nut slider seat 211. Two drive ropes 3 in opposite directions are connected to the nut slider seat 211. The drive rope 3 pointing towards the motor 201 changes direction through a fixed pulley 208, so that the two drive ropes 3 point in the same direction, so that the elongation (shortening) of one drive rope is equal to the shortening (elongation) of the other drive rope. The joint is bent by pulling the drive ropes 3. The drive box 2 is composed of multiple sets of motors 201, lead screws 203, linear optical axes 209, and pulleys 208, which pull multiple drive ropes 3 to realize the bending motion of the entire robotic arm.

[0036] In specific implementation, the corresponding structural settings include:

[0037] like Figure 3 andFigure 5 As shown, the quaternion joint 12 is formed by connecting the interarticular plate 101 to the connecting block 103 via the pin 102. The connecting block 103 can be rotated via the pin 102. The connecting block 103 is then connected to the connecting rod 104 via the pin 102. Three connecting rods 104 are circumferentially distributed on the interarticular plate 101 at 120° intervals. The other end of the connecting rod 104 is connected to the gear connecting block 105. The gear connecting block 105 is connected to the gear-bearing plate 106 at a position symmetrical to the connecting block 103. After the three connecting rods 104 are fully connected, they constrain each other to form the quaternion joint 12. The gear linkage joint 11 consists of two quaternion joints 12 placed symmetrically. The quaternion joints 12 are fixed to the joint connectors 108 by screws 107. The gear connecting blocks 105 in the two quaternion joints 12 mesh with each other, so that the six connecting rods 104 are mutually constrained and the two quaternion joints 12 bend at equal angles. The end of the robotic arm 1 is modularly composed of five gear linkage joints 11. Each pair of gear linkage joints 11 is connected and fixed to a joint connector 108 by screws 107.

[0038] like Figure 2 As shown, the motor 201 is connected to the lead screw 203 via a coupling 202. The left end of the lead screw 203 is fixed to the lead screw fixing plate 205 via a lead screw fixing seat 204, and the right side of the lead screw is placed on the lead screw support plate 207 via a lead screw support seat 206. A fixed pulley 208 is placed on the upper side of the lead screw fixing seat 204 on the lead screw fixing plate 205, and an optical axis support seat 210 for fixing the linear optical axis 209 is placed on the lower side of the lead screw fixing seat 204. The lower side of the nut slider seat 211 is connected to the optical axis slider 212, and the upper side of the nut slider seat 211 is provided with a threaded hole. This threaded hole fixes a self-locking wire lock 213, which can be connected to the drive rope 3. The center hole of the wire lock 213 must be at the same height as the bottom end of the pulley 208. Ten sets of motors 201, lead screws 203, linear shafts 209, and pulleys 208 are arranged in two rows of five columns each, one above the other, between the lead screw fixing plate 205 and the lead screw support plate 207. The lead screw fixing plate 205 and the lead screw support plate 207 are fixedly connected by four housing positioning plates 214 to form the housing frame. The lead screw fixing plate 205 and the lead screw support plate 207 are fixed to the housing positioning plates 214 by L-shaped connectors 215. The lead screw support plate 207 has threaded holes for connecting conduit connectors 216 at the positions corresponding to the pulleys 208 and the nut slider seat 211. These threaded holes must also correspond to the center hole of the cable lock 213 and the height of the pulleys 208. Figure 2 As shown, when motor 201 rotates, it drives lead screw 203 to rotate, and the nut slider seat 211 on it will move along the axial direction of lead screw 203, causing the ropes on both sides to stretch. The amount of change in the ropes on both sides is the same, which can be compared with... Figure 3 The gear linkage joint is engaged, pulling the joint to bend, thereby causing the end of the robotic arm to bend.

[0039] like Figure 3 and Figure 5 As shown, the quaternion joint 12 has the characteristic that the total length of the two ropes at the symmetrical rope holes remains unchanged. That is, when the quaternion joint 12 is bent, the elongation of one rope at the symmetrical position is equal to the shortening of the other rope; the gear linkage joint 11 also has this characteristic.

[0040] like Figure 4 As shown, Figure 4 (a) is a schematic diagram of the gear linkage joint 11 without bending the drive rope length. Figure 4 (b) is a schematic diagram of the change in rope length driven by the bending state of the gear linkage joint 11. The quaternion joint 12 rotates along the semi-circular trajectory shown in the figure. When the quaternion joint 12 bends, the distance between the center of the balls remains unchanged, and the difference between the lower left rope length 301 and the lower ball center distance 306 is equal to the difference between the lower ball center distance 306 and the lower right rope length 305. That is, the change in rope length on both sides is equal. Due to the characteristics of gear linkage, the lengths of the lower left rope length 301 and the upper left rope length 302 are always equal, the lengths of the upper right rope length 304 and the lower right rope length 305 are always equal, and the lengths of the lower ball center distance 306 and the upper ball center distance 303 are also always equal. It can be seen that the change in rope length on both sides of the gear linkage joint 11 is also equal.

[0041] like Figure 6 As shown, the joint connector 108 has three protruding structures with threaded holes inside, which are connected and fixed to the joint plate 101 by screws 107, and increase the distance between the two side plates of the joint connector 108, so as to connect with the quaternion joint 12; the joint connector 108 has 20 rope holes distributed around its outer circumference, and the end face of the rope hole is rounded to reduce the friction between the rope and the rope hole; the outer surface of the joint connector 108 is set in a concave shape to reduce the rope friction and reduce the difficulty of processing the small rope holes.

[0042] like Figure 7 As shown, the root end of the robotic arm 1 is provided with a root joint connector 109. The root joint connector 109 is provided with a rope hole for connecting to the conduit connector 216. The conduit connector 216 on the root joint connector 109 is connected to the lead screw support plate 207 and the wire conduit 218 is connected.

[0043] like Figure 8 As shown, the robotic arm end 1 is connected to the drive box 2 via a box-arm connector 110. The left end of the box-arm connector 110 is embedded in the lead screw support plate 207 and fixed with screws; the right end of the box-arm connector 110 is connected to the root joint connector 109.

[0044] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. Any embodiment that achieves the technical effects of the present invention using the same means should fall within the protection scope of the present invention. Within the protection scope of the present invention, various modifications and variations can be made to the technical solutions and / or implementation methods.

Claims

1. A quaternion-jointed serpentine robotic arm based on gear linkage, characterized in that: The serpentine robotic arm consists of a robotic arm end (1), a drive box (2), and a drive rope (3); The end of the robotic arm (1) is modularly composed of multiple gear linkage joints (11), each gear linkage joint (11) is composed of quaternion joints (12); the quaternion joints (12) are constrained by three connecting rods (104), and the bending of the joint is achieved by simulating the rolling of two hemispheres; the two quaternion joints (12) are connected by gear meshing, so that the six connecting rods (104) in the two quaternion joints (12) are constrained by each other, so that the two quaternion joints (12) can bend at the same angle; The robotic arm end (1) structure includes: The quaternion joint (12) is formed by connecting the inter-articular plate (101) to the connecting block (103) via the pin (102). The connecting block (103) can rotate via the pin (102). The connecting block (103) is connected to the connecting rod (104) via the pin (102). Three connecting rods (104) are connected in a circumferential arrangement at 120° intervals on the inter-articular plate (101). The other end of the connecting rod (104) is connected to the gear connecting block (105). The gear connecting block (105) is connected to the gear-hole plate (106) at a position symmetrical to the connecting block (103). After the three connecting rods (104) are fully connected, they constrain each other to form the quaternion joint (12). The gear linkage joint (11) is composed of two quaternion joints (12) placed symmetrically. The quaternion joints (12) are fixed to the joint connectors (108) by screws (107). The gear connecting blocks (105) in the two quaternion joints (12) mesh with each other. The drive box (2) consists of a motor (201) connected to a lead screw (203). The motor (201) drives the lead screw (203) to rotate. The linear optical axis (209) determines the direction of movement of the lead screw nut (217), realizing the linear reciprocating motion of the nut slider seat (211). Two drive ropes (3) with opposite directions are connected to the nut slider seat (211). The drive rope (3) pointing towards the motor (201) changes direction through a fixed pulley (208), so that the two drive ropes (3) point in the same direction, so that the elongation or shortening of one drive rope is equal to the shortening or elongation of the other drive rope. The joint is bent by pulling the drive ropes (3). The drive box (2) is composed of multiple sets of motors (201), lead screws (203), linear optical axes (209), and pulleys (208), and then multiple drive ropes (3) are pulled to realize the bending motion of the entire robotic arm.

2. The quaternion-jointed serpentine robotic arm based on gear linkage according to claim 1, characterized in that: The robotic arm end (1) structure also includes: The end of the robotic arm (1) is modularly composed of five gear linkage joints (11), and each pair of gear linkage joints (11) is connected and fixed to a joint connector (108) by screws (107).

3. The quaternion-jointed serpentine robotic arm based on gear linkage according to claim 1, characterized in that: The drive box (2) structure includes: The motor (201) is connected to the lead screw (203) via a coupling (202). The left end of the lead screw is fixed to the lead screw fixing plate (205) via a lead screw fixing seat (204), and the right side of the lead screw is placed on the lead screw support plate (207) via a lead screw support seat (206). A fixed pulley (208) is placed on the upper side of the lead screw fixing seat (204) on the lead screw fixing plate, and an optical axis support seat (210) for fixing the linear optical axis (209) is placed on the lower side of the lead screw fixing seat (204). The lower side of the nut slider seat (211) is connected to the optical axis slider (212), and a threaded hole is provided on the upper side of the nut slider seat (211). The threaded hole fixes a self-locking wire lock (213). 3) Connect to the drive rope (3); place two rows of five columns each, totaling ten sets of motors (201), screws (203), linear optical shafts (209) and pulleys (208) between the screw fixing plate (205) and the screw support plate (207); the screw fixing plate (205) and the screw support plate (207) are fixedly connected by four box positioning plates (214) to form the box shell frame, and the screw fixing plate (205) and the screw support plate (207) are fixed to the box positioning plate (214) by L-shaped connectors (215); the screw support plate (207) is provided with threaded holes for connecting the conduit connector (216) at the positions corresponding to the pulley (208) and the nut slider seat (211).

4. The quaternion-jointed serpentine robotic arm based on gear linkage according to claim 1, characterized in that: The quaternion joint (12) has the characteristic that the sum of the lengths of the two ropes at the symmetrical rope holes remains unchanged. That is, when the quaternion joint (12) is bent, the elongation of one rope at the symmetrical position is equal to the shortening of the other rope. The gear linkage joint (11) also has this characteristic.

5. The quaternion-jointed serpentine robotic arm based on gear linkage according to claim 2, characterized in that: The joint connector (108) has three protruding structures with threaded holes inside, which are connected and fixed to the joint plate (101) by screws (107) and increase the distance between the two side plates of the joint connector (108) to connect with the quaternion joint (12); the joint connector (108) has 20 rope holes distributed around its outer circumference, and the end face of the rope hole is rounded to reduce the friction between the rope and the rope hole; the joint connector (108) is set in a concave shape on the outside to reduce the friction of the rope and reduce the difficulty of processing the small rope holes.

6. The quaternion-jointed serpentine robotic arm based on gear linkage according to claim 2, characterized in that: A root joint connector (109) is provided at the root of the arm end (1) of the robotic arm. The root joint connector (109) is provided with a rope hole that connects to the conduit connector (216). The conduit connector (216) on the root joint connector (109) is connected to the wire conduit (218) on the corresponding conduit connector (216) on the screw support plate (207).

7. The quaternion-jointed serpentine robotic arm based on gear linkage according to claim 1, characterized in that: The arm end (1) of the robotic arm is connected to the drive box (2) through a box-arm connector (110). The left end of the box-arm connector (110) is embedded in the lead screw support plate (207) and fixed by screws. The right end of the box-arm connector (110) is connected to the root joint connector (109).

Images