A precision linkage robotic arm module based on bevel gears

Abstract

A precision linkage robotic arm module based on bevel gears consists of two drive ropes, a third arm, a second joint, a second arm, a first joint, a first arm, and some connecting parts. The two drive ropes work together to extend and retract in sequence; for example, when one rope extends by one centimeter, the other shortens by one centimeter. In the initial state of the robotic arm module, the third arm is fixed, and the entire module is in a straight position. When the two drive ropes move in coordination, they drive the first arm to rotate by an angle θ. Under the action of the linkage device, the second arm rotates relative to the third arm by an angle θ, achieving a precise linkage effect with equal angles. The precision linkage robotic arm module of this invention uses bevel gears to achieve linkage, which ensures a strict transmission ratio, high linkage accuracy, and improves the linkage efficiency of the robotic arm module.

Description

Technical Field

[0001] This invention relates to a precision linkage robotic arm module based on bevel gears, belonging to the field of robotic arms. Background Technology

[0002] With the development of science and technology, robotic arms are gradually replacing manual labor in performing tedious, dangerous, and complex tasks, reducing human workload and improving safety. Currently, the most commonly used type of robotic arm is the articulated robotic arm. However, its movement is limited in confined, unstructured spaces such as engine rooms, nuclear power plants, and tunnel boring machines, and its large weight and size cannot meet practical needs. To address these issues, rope-driven robotic arms have emerged. These arms employ a rear-mounted drive mechanism, significantly reducing the weight and size of the robotic arm structure. Using universal joints as connecting joints increases the robotic arm's degrees of freedom and further expands its range of motion. However, each arm in a rope-driven robotic arm requires three ropes for drive control. As the robotic arm's degrees of freedom increase, the number of drive ropes triples, making the drive system extremely complex and limiting the increase in the robotic arm's degrees of freedom. Therefore, researchers have proposed linked robotic arms, which interconnect the movements of multiple joints to achieve synchronized movement, increasing the degrees of freedom while reducing the number of drive ropes.

[0003] However, most existing robotic arm linkages are achieved through rope linkage, such as the technical solutions described in Chinese patents CN201711471782.7 and CN201711471781.2. Since ropes are elastic bodies, they will undergo elastic deformation after working for a period of time, which will lead to linkage errors. In addition, rope tensioning function is required, resulting in complex structure. Furthermore, the overall rigidity is not high due to the use of ropes. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art, realize high-precision linkage of the precision linkage robotic arm module and improve the overall rigidity of the robotic arm.

[0005] The objective of this invention is achieved through the following technical solutions:

[0006] A precision linkage robotic arm module based on bevel gears includes a third arm, a second joint, a second arm, a first joint, a first arm, and two drive ropes;

[0007] The first joint includes a first lug, a first transmission wheel, a first transmission shaft, a second lug, a third lug, a first center block, a second transmission shaft, a fourth lug, and a second transmission wheel;

[0008] The second joint includes the fifth lug, the fourth transmission wheel, the third transmission shaft, the sixth lug, the third transmission wheel, the seventh lug, the fourth transmission shaft, the eighth lug, and the second center block;

[0009] The second boom includes a hollow housing, a first connecting shaft, a connecting bearing, and a second connecting shaft;

[0010] The first lug is bolted to the first arm, and the third lug is also bolted to the first arm. The first lug is keyed to the first drive shaft, and the third lug is keyed to the second drive shaft. The first drive wheel is keyed to the first drive shaft. One end of the first drive shaft is keyed to the first center block, and the other end is keyed to the second lug via a copper sleeve, allowing for relative rotation. One end of the second drive shaft is keyed to the first center block, and the other end is keyed to the fourth lug via a copper sleeve, also allowing for relative rotation. Ultimately, the first lug, first drive wheel, first drive shaft, first center block, second drive shaft, and third lug are fixed as a detachable unit, and this unit can rotate relative to the second and fourth lugs. The axial positions of the components in the first joint connected to the first and second drive shafts are fixed by sleeves.

[0011] The second and fourth lugs are both connected to the hollow shell and are symmetrically distributed; the second drive wheel meshes with the first drive wheel via bevel gears, the second drive wheel is connected to the first connecting shaft via a key, the first connecting shaft is connected to the connecting bearing via a key, the connecting bearing is fixed to the hollow shell as a whole via an interference fit, the second connecting shaft is connected to the connecting bearing via a key, the first connecting shaft and the second connecting shaft can rotate synchronously relative to the connecting bearing, and the second drive wheel is connected via a key;

[0012] The fifth and seventh lugs are both connected to the hollow shell and are symmetrically distributed; the third and fourth transmission wheels mesh with each other via bevel gears, the fourth transmission wheel is connected to the third transmission shaft via a key, one end of the third transmission shaft is connected to the second center block via a key, and the other end is connected to the sixth lug via a key, the fifth lug and the third transmission shaft have a clearance fit, which can realize relative rotational motion, the seventh lug and the fourth transmission shaft have a clearance fit, which can realize relative rotational motion, one end of the fourth transmission shaft is connected to the second center block via a key, and the other end is connected to the eighth lug via a key, the sixth and eighth lugs are both connected to the third arm and are symmetrically distributed;

[0013] Two drive ropes pass through the rope holes on the third arm, the hollow shell, and the first arm in sequence and are symmetrically distributed, and are fixed to the end of the first arm.

[0014] In one embodiment of the present invention, two drive ropes cooperate to extend and retract in length, thereby achieving the rotation of the robotic arm.

[0015] In one embodiment of the present invention, when the two drive ropes move in coordination, they drive the first arm to rotate by an angle θ. Since the first lug and the third lug are both connected to the first arm by bolts, and the first lug, the first transmission wheel, the first transmission shaft, the first center block, the second transmission shaft, and the third lug are fixed as a whole and the whole can rotate relative to the second lug and the fourth lug, the whole formed by the first arm and the first lug, the first transmission wheel, the first transmission shaft, the first center block, the second transmission shaft, and the third lug together rotate relative to the second lug and the fourth lug by an angle θ.

[0016] In one embodiment of the present invention, the second transmission wheel and the first transmission wheel mesh with each other via bevel gears, with a transmission ratio of m:n; the second transmission wheel and the third transmission wheel have a transmission ratio of m:n; the third transmission wheel and the fourth transmission wheel mesh with each other via bevel gears, with a transmission ratio of m:n.

[0017] In one embodiment of the present invention, the first ear and the third ear are symmetrically distributed.

[0018] In one embodiment of the present invention, the second ear and the fourth ear are symmetrically distributed.

[0019] In one embodiment of the present invention, the second and fourth lugs are both connected to the hollow shell by bolts and are symmetrically distributed.

[0020] In one embodiment of the present invention, the fifth and seventh lugs are both connected to the hollow shell by bolts and are symmetrically distributed.

[0021] In one embodiment of the present invention, the sixth lug and the eighth lug are both connected to the third arm by bolts and are symmetrically distributed.

[0022] In one embodiment of the present invention, when the transmission ratio between the first transmission wheel and the second transmission wheel is 1:2, and the transmission ratios between the second transmission wheel and the third transmission wheel and the third transmission wheel and the fourth transmission wheel are all 1:1, the first arm rotates relative to the second arm by an angle θ, and the second arm rotates relative to the third arm by an angle 2θ.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The precision linkage robotic arm module in this invention uses bevel gears to achieve linkage. The bevel gears can ensure a strict transmission ratio, high linkage accuracy, and improve the linkage efficiency of the robotic arm module.

[0025] (2) The precision linkage robotic arm module in this invention uses bevel gears to achieve linkage, which enhances the overall rigidity of the robotic arm module and improves the end-effector accuracy compared to using ropes.

[0026] (3) The joints and arms in the precision linkage robotic arm module of the present invention are connected by bolts, which makes it easier to assemble and disassemble.

[0027] (4) The joint parts in the precision linkage robotic arm module of the present invention are connected by keys, which facilitates assembly, disassembly and adjustment and improves efficiency.

[0028] (5) The precision linkage robotic arm module of the present invention can replace the bevel gear with the corresponding transmission ratio according to the required linkage angle ratio, thereby realizing the variable angle linkage function and expanding the application range of the module.

[0029] (6) Compared with existing domestic and foreign solutions, this technical solution can achieve high-precision linkage function, while improving the overall rigidity of the robotic arm. Moreover, the basic technology is relatively mature and easy to implement.

[0030] (7) The precision linkage robotic arm module of the present invention can ensure a strict transmission ratio with bevel gears and does not need to consider the loosening of the rope when using the rope method, thus achieving high rigidity and high precision. Attached Figure Description

[0031] Figure 1 This is a structural diagram of the linkage robotic arm module;

[0032] Figure 2 This is a schematic diagram of the linkage principle of the robotic arm module;

[0033] Figure 3 This is a structural diagram of the second boom;

[0034] Figure 4 This is a first-person view of the working state of the robotic arm module.

[0035] Figure 5 This is a second-person view of the working state of the linkage robotic arm module. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0037] The purpose of this invention is to provide a precision linkage robotic arm module based on bevel gears, which can achieve high-precision linkage and improve the overall rigidity of the robotic arm.

[0038] The linkage robotic arm module of this invention consists of two drive ropes 1, a third arm 2, a second joint 3, a second arm 4, a first joint 5, a first arm 6, and some connecting parts. The two drive ropes 1 cooperate to achieve a length-to-length extension and retraction; for example, when one extends by one centimeter, the other shortens by one centimeter. In the initial state of the robotic arm module, the third arm 2 is fixed, and the entire module is in a straight state. When the two drive ropes 1 move in coordination, they drive the first arm 6 to rotate by an angle θ. Under the action of the linkage device, the second arm 4 rotates relative to the third arm 2 by an angle θ, achieving a precise linkage effect with equal angles.

[0039] Specifically:

[0040] In this invention, the linkage robotic arm module consists of two drive ropes 1, a third arm 2, a second joint 3, a second arm 4, a first joint 5, a first arm 6, and some connecting parts, such as... Figure 1 As shown. Figure 2 As shown, the first joint 5 includes a first lug 5-1, a first transmission wheel 5-2, a first transmission shaft 5-3, a second lug 5-4, a third lug 5-5, a first center block 5-6, a second transmission shaft 5-7, a fourth lug 5-8, and a second transmission wheel 5-9. The second joint 3 includes a fifth lug 3-1, a fourth transmission wheel 3-2, a third transmission shaft 3-3, a sixth lug 3-4, a third transmission wheel 3-5, a seventh lug 3-6, a fourth transmission shaft 3-7, an eighth lug 3-8, and a second center block 3-9. Figure 3 As shown, the second arm 4 includes a hollow housing 4-1, a first connecting shaft 4-2, a connecting bearing 4-3, and a second connecting shaft 4-4.

[0041] The first lug 5-1 is bolted to the first arm 6, and the third lug 5-5 is also bolted to the first arm 6. The first lug 5-1 and the third lug 5-5 are symmetrically distributed. The first lug 5-1 is connected to the first drive shaft 5-3 by a key, and the third lug 5-5 is connected to the second drive shaft 5-7 by a key. The first drive wheel 5-2 is connected to the first drive shaft 5-3 by a key. One end of the first drive shaft 5-3 is connected to the first center block 5-6 by a key, and the other end is connected to the second lug 5-4 by a copper... The first joint 5 is connected to the first center block 5-6 via a key, and the other end is connected to the fourth lug 5-8 via a copper sleeve, allowing for relative rotation. The second lug 5-4 and the fourth lug 5-8 are symmetrically distributed, ultimately fixing the first lug 5-1, the first transmission wheel 5-2, the first transmission shaft 5-3, the first center block 5-6, the second transmission shaft 5-7, and the third lug 5-5 into a easily detachable whole, which can rotate relative to the second lug 5-4 and the fourth lug 5-8. The axial positions of the components in the first joint 5 connected to the first transmission shaft 5-3 and the second transmission shaft 5-7 are fixed by sleeves.

[0042] The second lug 5-4 and the fourth lug 5-8 are both bolted to the hollow shell 4-1 and are symmetrically distributed. The second transmission wheel 5-9 meshes with the first transmission wheel 5-2 via bevel gears. The second transmission wheel 5-9 is keyed to the first connecting shaft 4-2. The first connecting shaft 4-2 is keyed to the connecting bearing 4-3. The connecting bearing 4-3 is fixed to the hollow shell 4-1 as a whole via an interference fit. The second connecting shaft 4-4 is keyed to the connecting bearing 4-3. The first connecting shaft 4-2 and the second connecting shaft 4-4 can rotate synchronously relative to the connecting bearing 4-3. The second connecting shaft 4-4 is keyed to the third transmission wheel 3-5.

[0043] The fifth lug 3-1 and the seventh lug 3-6 are both connected to the hollow shell 4-1 by bolts and are symmetrically distributed. The third transmission wheel 3-5 and the fourth transmission wheel 3-2 mesh with each other via bevel gears. The fourth transmission wheel 3-2 is connected to the third transmission shaft 3-3 by a key. One end of the third transmission shaft 3-3 is connected to the second center block 3-9 by a key, and the other end is connected to the sixth lug 3-4 by a key. The fifth lug 3-1 and the third transmission shaft 3-3 have a clearance fit, which allows for relative rotational movement. The seventh lug 3-6 and the fourth transmission shaft 3-7 have a clearance fit, which allows for relative rotational movement. One end of the fourth transmission shaft 3-7 is connected to the second center block 3-9 by a key, and the other end is connected to the eighth lug 3-8 by a key. The sixth lug 3-4 and the eighth lug 3-8 are both connected to the third arm 2 by bolts and are symmetrically distributed.

[0044] Two drive ropes 1 pass through the rope holes on the third arm 2, the hollow shell 4-1, and the first arm 6 in sequence and are symmetrically distributed, and are fixed to the end of the first arm 6.

[0045] The working principle of the linkage robotic arm module is as follows:

[0046] Two drive ropes 1 work together to extend and retract in length; for example, when one rope extends by one centimeter, the other shortens by one centimeter. In the initial state of the robotic arm module, the third arm 2 is fixed, and the entire module is in a straight position. When the two drive ropes 1 move in coordination, they drive the first arm 6 to rotate by an angle θ. Since the first lug 5-1 and the third lug 5-5 are both bolted to the first arm 6, and the first lug 5-1, the first transmission wheel 5-2, the first transmission shaft 5-3, the first center block 5-6, the second transmission shaft 5-7, and the third lug 5-5 are fixed as a whole and can rotate relative to the second lug 5-4 and the fourth lug 5-8, the first arm 6 and the whole formed by the first lug 5-1, the first transmission wheel 5-2, the first transmission shaft 5-3, the first center block 5-6, the second transmission shaft 5-7, and the third lug 5-5 rotate together relative to the second lug 5-4 and the fourth lug 5-8 by an angle θ.

[0047] The second transmission wheel 5-9 meshes with the first transmission wheel 5-2 via bevel gears, and the transmission ratio is m:n (in this embodiment, m:n = 1:1). The second transmission wheel 5-9 rotates by the same angle -θ. The second transmission wheel 5-9 is connected to the first connecting shaft 4-2 via a key. The first connecting shaft 4-2 is connected to the connecting bearing 4-3 via a key. The connecting bearing 4-3 is fixed to the hollow housing 4-1 via an interference fit. The second connecting shaft 4-4 is connected to the connecting bearing 4-3 via a key. The first connecting shaft 4-2 and the second connecting shaft 4-4 can rotate synchronously relative to the connecting bearing 4-3. The second connecting shaft 4-4 is connected to the third transmission wheel 3-5 via a key, and the transmission ratio between the second transmission wheel 5-9 and the third transmission wheel 3-5 is m:n (in this embodiment, m:n = 1:1). Therefore, when the second transmission wheel 5-9 rotates by an angle -θ, the third transmission wheel 3-5 rotates by an angle θ. The third transmission wheel 3-5 and the fourth transmission wheel 3-2 mesh with each other via bevel gears, and the transmission ratio is m:n (in this embodiment of the invention, m:n = 1:1). Under normal circumstances, when the third transmission wheel 3-5 rotates by an angle θ, the fourth transmission wheel 3-2 rotates by an angle -θ. However, since the fourth transmission wheel 3-2 is connected to the third transmission shaft 3-3 by a key, one end of the third transmission shaft 3-3 is connected to the second center block 3-9 by a key, and the other end is connected to the sixth lug 3-4 by a key, the fifth lug 3-1 and the third transmission shaft 3-3 have a clearance fit, allowing for relative rotational motion. The seventh lug 3-6 and the fourth transmission shaft 3-7 have a clearance fit, allowing for relative rotational motion. One end of the fourth transmission shaft 3-7 is connected to the second center block 3-9 by a key, and the other end is connected to the eighth lug 3-8 by a key. The sixth lug 3-4 and the eighth lug 3-8 are both connected to the third arm 2 by bolts and are symmetrically distributed. The third arm 2 is fixed. Therefore, under the constraint of the reaction force, the first arm 6, the first joint 5, the second arm 4, the fifth lug 3-1, and the seventh lug 3-6 rotate as a whole by an angle θ. The final shape of the robotic arm module is as follows: Figure 4 and Figure 5 As shown, the third arm 2 is fixed, the first arm 6 rotates relative to the second arm 4 by an angle θ, and the second arm 4 rotates relative to the third arm 2 by an angle θ, achieving the effect of precise linkage at equal angles.

[0048] At the same time, when the transmission ratio between the first transmission wheel 5-2 and the second transmission wheel 5-9 is 1:2, and the transmission ratio between the second transmission wheel 5-9 and the third transmission wheel 3-5 and the third transmission wheel 3-5 and the fourth transmission wheel 3-2 is 1:1, the first arm 6 rotates relative to the second arm 4 by an angle θ, and the second arm 4 rotates relative to the third arm 2 by an angle 2θ, achieving the effect of precise linkage with variable angle.

[0049] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0050] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A precision linkage robotic arm module based on bevel gears, characterized in that, It includes a third boom, a second joint, a second boom, a first joint, a first boom, and two drive ropes; The first joint includes a first lug, a first transmission wheel, a first transmission shaft, a second lug, a third lug, a first center block, a second transmission shaft, a fourth lug, and a second transmission wheel; The second joint includes the fifth lug, the fourth transmission wheel, the third transmission shaft, the sixth lug, the third transmission wheel, the seventh lug, the fourth transmission shaft, the eighth lug, and the second center block; The second boom includes a hollow housing, a first connecting shaft, a connecting bearing, and a second connecting shaft; The first lug is bolted to the first arm, and the third lug is also bolted to the first arm. The first lug is keyed to the first drive shaft, and the third lug is keyed to the second drive shaft. The first drive wheel is keyed to the first drive shaft. One end of the first drive shaft is keyed to the first center block, and the other end is keyed to the second lug via a copper sleeve, allowing for relative rotation. One end of the second drive shaft is keyed to the first center block, and the other end is keyed to the fourth lug via a copper sleeve, also allowing for relative rotation. Ultimately, the first lug, first drive wheel, first drive shaft, first center block, second drive shaft, and third lug are fixed as a detachable unit, and this unit can rotate relative to the second and fourth lugs. The axial positions of the components in the first joint connected to the first and second drive shafts are fixed by sleeves. The second and fourth lugs are both connected to the hollow shell and are symmetrically distributed; the second drive wheel meshes with the first drive wheel via bevel gears, the second drive wheel is connected to the first connecting shaft via a key, the first connecting shaft is connected to the connecting bearing via a key, the connecting bearing is fixed to the hollow shell as a whole via an interference fit, the second connecting shaft is connected to the connecting bearing via a key, the first connecting shaft and the second connecting shaft can rotate synchronously relative to the connecting bearing, and the second drive wheel is connected via a key; The fifth and seventh lugs are both connected to the hollow shell and are symmetrically distributed; the third and fourth transmission wheels mesh with each other via bevel gears, the fourth transmission wheel is connected to the third transmission shaft via a key, one end of the third transmission shaft is connected to the second center block via a key, and the other end is connected to the sixth lug via a key, the fifth lug and the third transmission shaft have a clearance fit, which can realize relative rotational motion, the seventh lug and the fourth transmission shaft have a clearance fit, which can realize relative rotational motion, one end of the fourth transmission shaft is connected to the second center block via a key, and the other end is connected to the eighth lug via a key, the sixth and eighth lugs are both connected to the third arm and are symmetrically distributed; Two drive ropes pass through the rope holes on the third arm, the hollow shell, and the first arm in sequence and are symmetrically distributed, and are fixed to the end of the first arm.

2. The precision linkage robotic arm module according to claim 1, characterized in that, The two drive ropes work together to extend and retract, thereby enabling the robotic arm to rotate at different angles.

3. The precision linkage robotic arm module according to claim 2, characterized in that, When the two drive ropes move in coordination, they drive the first arm to rotate by an angle θ. Since the first and third lugs are both connected to the first arm by bolts, and the first lug, the first drive wheel, the first drive shaft, the first center block, the second drive shaft, and the third lug are fixed as a whole and the whole can rotate relative to the second and fourth lugs, the whole formed by the first arm and the first lug, the first drive wheel, the first drive shaft, the first center block, the second drive shaft, and the third lug together rotate relative to the second and fourth lugs by an angle θ.

4. The precision linkage robotic arm module according to claim 1, characterized in that, The second transmission wheel meshes with the first transmission wheel via bevel gears, with a transmission ratio of m:n. The transmission ratio between the second and third transmission wheels is m:n; the third and fourth transmission wheels mesh with each other via bevel gears, and the transmission ratio is m:n.

5. The precision linkage robotic arm module according to claim 1, characterized in that, The first and third auricles are symmetrically distributed.

6. The precision linkage robotic arm module according to claim 1, characterized in that, The second and fourth lugs are both connected to the hollow shell by bolts and are symmetrically distributed.

7. The precision linkage robotic arm module according to claim 1, characterized in that, The fifth and seventh lugs are both connected to the hollow shell by bolts and are symmetrically distributed.

8. The precision linkage robotic arm module according to claim 1, characterized in that, The sixth and eighth lugs are both connected to the third arm by bolts and are symmetrically distributed.

9. The precision linkage robotic arm module according to claim 1, characterized in that, When the transmission ratio between the first and second transmission wheels is 1:2, and the transmission ratios between the second and third transmission wheels and between the third and fourth transmission wheels are all 1:1, the first arm rotates relative to the second arm by an angle θ, and the second arm rotates relative to the third arm by an angle 2θ.

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