A multi-degree-of-freedom robotic arm that can be equipped on small and medium-sized mobile platforms

Abstract

The present invention relates to the field of robotic arms, and more specifically, to a multi-degree-of-freedom robotic arm that can be mounted on small or medium-sized mobile platforms. The robotic arm comprises a base, a first servo mounted on the base, and a turntable connecting the first servo and a plurality of connecting arms. The turntable comprises a fixed plate fixedly connected to the base and a rotating plate rotatably connected to the fixed plate, and the rotating plate is connected to the output shaft of the first servo. The weight of the robotic arm and the object being grasped is borne by the base, while the output shaft of the first servo only needs to bear torque. This achieves the separation of force transmission and load bearing in the robotic arm, improves the reliability and lifespan of the robotic arm, and reduces vibration of the robotic arm during operation.

Description

Technical Field

[0001] The present invention relates to the field of robotic arms, and more particularly, to a multi-degree-of-freedom robotic arm that can be equipped on small or medium-sized mobile platforms. Background Art

[0002] In recent years, industrial robots have made a significant impact in the manufacturing industry, performing tasks such as handling, welding, assembly, and painting with precision and stability. Meanwhile, a wide variety of civilian robots are widely used for tasks such as aerial photography, surveying and mapping, exploration, inspection, positioning, film and television production, and communications relay. Compared to industrial robots, the tasks that civilian robots can perform are relatively limited. These tasks, such as grasping, assembly, and transportation, all rely on environmental awareness. These tasks require active interaction with the environment, but are difficult for small civilian robots to accomplish.

[0003] Industrial robots are arm-type robots characterized by high power, high torque, high precision, high payload, and low error. These features enable them to actively interact with the outside world and complete a variety of challenging industrial manufacturing tasks. However, these arm-type robots cannot be directly transferred to small civilian robots. Industrial robots are heavy and bulky, and their high power supply voltage and power requirements make them difficult to install on small civilian robots.

[0004] In order to reduce the weight of small and medium-sized arm-type robots on civilian robots, it is necessary to replace heavy motors with lighter servos. However, in addition to outputting torque, the servo output shaft must also withstand huge bending moments and the weight of almost the entire robotic arm plus the target object. This will generate complex three-dimensional stresses on the servo output shaft, which will not only cause fatigue failure of the servo output shaft and shorten its lifespan, but also cause the robotic arm to vibrate excessively, making it difficult to accurately grasp objects. In addition, the relative position relationship between the various joints of the existing robotic arm, the movement direction of each joint, and the arm length of each joint of the robotic arm are all fixed, and the structure and arm length of the robotic arm cannot be changed, which limits the scalability of the robotic arm. For example, the patent document with publication number CN207841381U discloses a multi-degree-of-freedom robotic arm. The first servo of the robotic arm not only outputs torque but also bears load during operation, which is prone to vibration. At the same time, the joints and arm lengths between the connecting arms are also fixed and cannot be adjusted. Summary of the Invention

[0005] In order to overcome the problem in the above-mentioned prior art that small and medium-sized robotic arms cannot accurately grasp objects due to shaking, the present invention provides a multi-degree-of-freedom robotic arm that can be equipped on small and medium-sized mobile platforms, thereby reducing the shaking of the robotic arm during work and changing the joints of the robotic arm to increase the applicability of the robotic arm.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform, comprising a base, a first servo installed on the base, a turntable connecting the first servo and several levels of connecting arms, the turntable comprising a fixed plate fixedly connected to the base, a rotating plate rotatably connected to the fixed plate, and the rotating plate is connected to the output shaft of the first servo.

[0007] In the working state, the load borne by the robotic arm is transferred to the rotating disk, and the rotating disk transfers the load to the fixed disk. The output shaft of the first servo does not bear the load brought by the robotic arm and only outputs torque, thereby realizing the separation of transmission and load, reducing the stress on the first servo and reducing vibration.

[0008] Preferably, the rotating disk is provided with a rotating metal sheet, and the fixed disk is provided with a fixed metal sheet; the fixed metal sheet is provided with a center hole, and the rotating metal sheet is provided with a hollow portion that fits into the center hole, and the end of the hollow portion close to the fixed metal sheet is provided with an extension portion that is clamped with the fixed metal sheet. The hollow portion of the rotating metal sheet passes through the center hole of the fixed metal sheet, and the extension portion is a frustum extending outward, which abuts against the end of the fixed metal sheet close to the base, thereby achieving the clamping connection between the rotating metal sheet and the fixed metal sheet. The load applied to the rotating disk is transmitted to the base through the extension portion, and the rotating metal sheet can rotate relative to the fixed metal sheet.

[0009] Preferably, the output shaft of the first servo is connected to the rotating disk via a connecting key. The rotating disk is provided with a keyway, and the connecting key extends into the keyway of the rotating disk, but is in direct contact with the rotating disk. Only when the output shaft rotates will the connecting key rotate with the rotating disk, thereby preventing the rotating disk from transferring other loads to the output shaft, ensuring that the output shaft only outputs torque, and reducing vibration of the robotic arm.

[0010] Preferably, a cavity is formed between the rotating metal sheet and the fixed metal sheet, and a ball bearing is placed in the cavity. The rotating metal sheet is provided with a downwardly concave groove, and the fixed metal sheet is provided with an upwardly concave groove. The two opposing grooves form the cavity for the ball bearing. The ball bearing in the cavity does not affect the rotation of both, while also sharing the load force exerted on the metal sheet turntable.

[0011] Preferably, the multiple connecting arms are provided with a connecting rod portion for articulated connection; the connecting rod portion comprises a base and a connecting rod shaft, the base being detachably fixedly connected to the connecting rod shaft. The connecting rod portion is a detachable structure. When the length of the robotic arm needs to be changed, the connecting rod shaft can be disassembled and the connecting rod shafts and bases of two or more joints can be reassembled to reduce the number of joints in the connecting arm, thereby achieving the change in arm length and improving the adaptability of the robotic arm.

[0012] Preferably, the connecting rod shaft includes a sleeve that fits over the base and a retaining sleeve that fits over the sleeve; the sleeve is engaged with the base, and the retaining sleeve is movable along the sleeve. When in use, the sleeve limits the engagement position between the sleeve and the base, allowing the shaft head and the base to separate. To disassemble, the sleeve is moved to a position outside the engagement position and pulled outward, making disassembly convenient.

[0013] Preferably, the shaft sleeve is provided with a through hole, the base is provided with a groove, and balls are mounted on the through hole and the groove; the limiting sleeve moves on the shaft sleeve through the elastic force of the elastic member, and the limiting sleeve is provided with an inclined surface that abuts the balls. In use, a portion of the balls pass through the through hole and enter the groove, so that the shaft sleeve and the base are snap-fitted, while the inclined surface of the limiting sleeve presses the balls, and the shaft sleeve and the base do not separate. When the shaft sleeve needs to be disassembled, the limiting sleeve is pushed to move, and the elastic member is stretched or compressed, so that the inclined surface of the limiting sleeve moves, and the inclined surface leaves space for accommodating the balls. The balls can move outward and leave the groove, and the shaft sleeve and the sleeve can move relative to each other, thereby achieving separation. After separation, the elastic member can push the limiting sleeve to reset. The shaft sleeve, the base and the limiting sleeve can be installed layer by layer, and the shaft sleeve and the base can be separated by only pushing the limiting sleeve, which makes disassembly more convenient.

[0014] Preferably, the base is provided with a clamping block on the end face close to the shaft sleeve, and the shaft sleeve is provided with a clamping groove matched with the clamping block. During installation, the clamping block is inserted into the clamping groove to place the base and the shaft sleeve in relative motion.

[0015] Preferably, the multiple connecting arms include a first connecting arm, a second connecting arm, and a third connecting arm connected in sequence. The first connecting arm includes a second steering gear, a first U-shaped arm connected to the second steering gear, a second U-shaped arm, and a connecting rod A connecting the first and second U-shaped arms. The second connecting arm includes a third steering gear connected to the second U-shaped arm, a connecting rod B connected to the third steering gear, and a third U-shaped arm connected to the connecting rod B. The third connecting arm includes a fourth steering gear connected to the third U-shaped arm, and a fifth steering gear connected to the fourth steering gear via a connecting plate. Connecting rods A and B are identical in structure, but are actually connecting rods installed in different locations. The second, third, and fourth steering gears can swing vertically, and the steering wheel of the fifth steering gear can be connected to an output mechanism such as a gripping mechanism. Connecting rods A and B can be disassembled based on usage or space, and the sleeve of connecting rod B can be installed on the base of connecting rod A to adjust the length of the connecting arm.

[0016] Preferably, the connecting rod is provided with a through hole. The cable for connecting the servo can pass through the through hole of the connecting rod, so that all the wires are hidden inside the connecting rod, reducing the obstruction of the wires to the movement of the robotic arm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: the weight of the robotic arm and the grasped object are borne by the base, and the output shaft of the first servo only needs to bear torque, which realizes the separation of transmission force and load of the robotic arm, improves the reliability and life of the robotic arm, and reduces the shaking of the robotic arm during operation; the connection part of the robotic arm used to connect the joints can be disassembled and then reassembled, so that the length of each connecting rod of the robotic arm as a whole can be changed at any time as needed to meet the needs of different working spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to the present invention;

[0019] Figure 2 yes Figure 1 Cross-sectional view of MM;

[0020] Figure 3 yes Figure 2 A partial enlarged view of position A;

[0021] Figure 4 It is a structural schematic diagram of another embodiment of the present invention, a multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform.

[0022] Figure 5 It is a structural schematic diagram of the connecting rod portion of the present invention;

[0023] Figure 6 yes Figure 5 Cross-sectional view of CC;

[0024] Figure 7 It is a schematic cross-sectional structural diagram of another embodiment of the connecting rod portion of the present invention. DETAILED DESCRIPTION

[0025] The drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate the embodiments, some components in the drawings may be omitted, enlarged, or reduced in size, and do not represent actual product dimensions. Those skilled in the art will understand that some well-known structures and their descriptions may be omitted from the drawings. The positional relationships depicted in the drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0026] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc. indicating the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0027] In order to facilitate reading and understanding in the drawings of the embodiments of the present invention, the front plate, the rear plate and the top plate in the casing structure are all shown.

[0028] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0029] Example 1

[0030] like Figure 1-3 The figure shows an embodiment of a multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform. The figure includes a base 1, a first servo 2 mounted on the base 1, a turntable 4 connecting the first servo 2 and a plurality of connecting arms 3. The turntable 4 includes a fixed plate 5 fixedly connected to the base 1, a rotating plate 6 rotatably connected to the fixed plate 5, and the rotating plate 6 is connected to the output shaft 201 of the first servo 2.

[0031] The rotating disk 6 is provided with a rotating metal sheet 601, and the fixed disk 5 is provided with a fixed metal sheet 501. The fixed metal sheet 501 is provided with a center hole 502, and the rotating metal sheet 601 is provided with a hollow portion 602 that fits into the center hole 502. The end of the hollow portion 602 close to the fixed metal sheet 501 is provided with an extension portion 603 that is clamped to the fixed metal sheet 501. The hollow portion 602 of the rotating metal sheet 601 passes through the center hole 502 of the fixed metal sheet 501, and the extension portion 603 is an outwardly extending frustum that abuts against the end of the fixed metal sheet 501 close to the base 1, thereby achieving the clamping connection between the rotating metal sheet 601 and the fixed metal sheet 501. The load applied to the rotating disk 6 is transmitted to the base 1 through the extension portion 603, and the rotating metal sheet 601 can rotate relative to the fixed metal sheet 501.

[0032] To further prevent the rotating disk 6 from transferring other loads to the output shaft 201, ensuring that the output shaft 201 only outputs torque and reducing arm vibration, the output shaft 201 of the first servo 2 is connected to the rotating disk 6 via a connecting key 202. The rotating disk 6 is provided with a keyway, and the connecting key extends into the keyway of the rotating disk 6 but does not directly contact the rotating disk 6. It only rotates with the rotating disk 6 when the output shaft rotates.

[0033] Additionally, a cavity is formed between the rotating metal sheet 601 and the fixed metal sheet 501, within which a ball bearing 604 is placed. The rotating metal sheet 601 has a downwardly concave groove, while the fixed metal sheet 501 has an upwardly concave groove. These two opposing grooves form the cavity for the ball bearing 604. The ball bearing 604 within the cavity does not affect the rotation of either metal sheet, while also sharing the load applied to the metal sheet turntable 4.

[0034] The working principle or workflow of the present invention is as follows: in the working state, the load borne by the robotic arm is transmitted to the rotating disk 4, and the rotating disk 4 transmits the load to the fixed disk 5. The output shaft 201 of the first servo 2 does not bear the load brought by the robotic arm and only outputs torque, thereby realizing the separation of transmission and load, reducing the stress on the first servo 2 and reducing vibration.

[0035] The beneficial effects of this embodiment are as follows: the weight of the robotic arm and the grasped object are all borne by the base 1, and the output shaft 201 of the first servo 2 only needs to bear torque, thereby realizing the separation of transmission force and load of the robotic arm, improving the reliability and life of the robotic arm, and reducing the vibration of the robotic arm during operation.

[0036] Example 2

[0037] Figure 4 Another embodiment of a multi-degree-of-freedom robotic arm that can be installed on small or medium-sized mobile platforms is shown. This differs from the first embodiment in that the multiple connecting arms comprise a first connecting arm 8, a second connecting arm 9, and a third connecting arm 10, which are connected in sequence. The first connecting arm 8 comprises a second servo 801, a first U-shaped arm 802 connected to the second servo 801, a second U-shaped arm 803, and a connecting rod A71 connecting the first and second U-shaped arms 802 and 803. The second connecting arm 9 comprises a third servo 901 connected to the second U-shaped arm 803, a connecting rod B72 connected to the third servo 901, and a third U-shaped arm 902 connected to the connecting rod B72. The third connecting arm 10 comprises a fourth servo 1001 connected to the third U-shaped arm 902, and a fifth servo 1003 connected to the fourth servo 1001 via a connecting plate 1002. The connecting rods A71 and B72 are identical in structure, but are actually connecting rods 7 installed in different locations. The second, third and fourth steering gears swing in the vertical direction, and the steering wheel of the fifth steering gear is connected to the clamping mechanism and other output mechanisms.

[0038] like Figure 5-6As shown, the connecting rod portion 7 includes a base 701 and a connecting rod shaft 702, and the base 701 is detachably fixedly connected to the connecting rod shaft 702, and the connecting rod shaft 702 is arranged at both ends of the base 701. The connecting rod portion 7 is a detachable structure. When the length of the robotic arm needs to be changed to another length, the connecting rod shaft 702 can be disassembled and the connecting rod shaft 702 of two or more joints and the base 701 can be reassembled to reduce the number of joints of the connecting arm, thereby changing the arm length of the robotic arm and improving the applicability of the robotic arm. When using the robotic arm, the connecting rod portion A71 and the connecting rod portion B72 can be disassembled according to the usage situation or space, and the shaft sleeve 7021 of the connecting rod portion B72 can be installed on the base 701 of the connecting rod portion A71 to change the length of the connecting arm.

[0039] The connecting rod shaft 702 includes a sleeve 7021 that fits over the base 701 and a retaining sleeve 7022 that fits over the sleeve 7021. The sleeve 7021 is engaged with the base 701, and the retaining sleeve 7022 is movable along the sleeve 7021. During use, the sleeve 7021 limits the engagement between the sleeve 7021 and the base 701, allowing the shaft head to separate from the base 701. To facilitate disassembly, the sleeve 7021 is moved to a position outside the engagement position and then pulled outward.

[0040] Specifically, the shaft sleeve 7021 is provided with a through hole 7023, and the base 701 is provided with a groove 7011. Balls 703 are mounted on the through hole 7023 and the groove 7011. The limiting sleeve 7022 is movable on the shaft sleeve 7021 by the elastic force of the elastic member 704. The limiting sleeve 7022 is provided with an inclined surface 7024 that abuts against the ball 703. In use, a portion of the ball 703 passes through the through hole 7023 and enters the groove, thereby achieving a snap connection between the shaft sleeve 7021 and the base 701. At the same time, the inclined surface 7024 of the limiting sleeve 7022 compresses the ball, preventing the shaft sleeve 7021 and the base 701 from separating. When the shaft sleeve 7021 needs to be removed, the limiting sleeve 7022 is pushed to move, and the elastic member 704 is stretched or compressed, causing the inclined surface 7024 of the limiting sleeve 7022 to move. The inclined surface 7024 leaves space for the ball 703, and the ball 703 can move outward and leave the groove 7011. The shaft sleeve 7021 and the base 701 can move relative to each other, thereby achieving separation. After separation, the elastic member 704 can push the limiting sleeve 7022 to return to its original position. The shaft sleeve 7021, the base 701, and the limiting sleeve 7022 can be installed layer by layer. The shaft sleeve 7021 and the base 701 can be separated by simply pushing the limiting sleeve 7022, making disassembly more convenient.

[0041] In addition, the connecting rod is provided with a through hole 705. The cable for connecting the servo can pass through the through hole 705 of the connecting rod, so that all the wires are hidden inside the connecting rod, reducing the obstruction of the wires to the movement of the manipulator.

[0042] Compared with Example 1, the beneficial effect of this embodiment is that the connection part of the robot arm used to connect the joints can be disassembled and then reassembled, so that the length of each connecting rod of the entire robot arm can be changed at any time as needed to meet the needs of different workspaces.

[0043] The working principle of this embodiment is consistent with that of embodiment 1.

[0044] Example 3

[0045] Figure 7 Another embodiment of the connecting rod portion is shown. Based on the second embodiment, the structure of the connecting rod portion is further defined. The difference from the second embodiment is that a clamping block 7012 is provided on the end surface of the base 701 near the shaft sleeve 7021, and the shaft sleeve 7021 is provided with a clamping groove 7025 that cooperates with the clamping block 7012. During installation, the clamping block 7012 is inserted into the clamping groove 7025, preventing the base 701 and the shaft sleeve 7021 from moving relative to each other.

[0046] The remaining features and working principles of this embodiment are consistent with those of embodiment 2.

[0047] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform, comprising a base (1), a first steering gear (2) mounted on the base (1), and a turntable (4) connecting the first steering gear (2) and a plurality of connecting arms (3), characterized in that: The turntable (4) comprises a fixed disk (5) fixedly connected to the base (1), and a rotating disk (6) rotatably connected to the fixed disk (5); the rotating disk (6) is connected to the output shaft (201) of the first steering gear (2); the output shaft (201) of the first steering gear (2) is connected to the rotating disk (6) via a connecting key (202); The rotating disk (6) is provided with a rotating metal sheet (601), and the fixed disk (5) is provided with a fixed metal sheet (501); the fixed metal sheet (501) is provided with a center hole (502), the rotating metal sheet (601) is provided with a hollow portion (602) fitted into the center hole (502), and an end of the hollow portion (602) close to the fixed metal sheet (501) is provided with an extension portion (603) engaged with the fixed metal sheet (501); A cavity is formed between the rotating metal sheet (601) and the fixed metal sheet (501), and a ball (604) is placed in the cavity.

2. The multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to claim 1, characterized in that: The plurality of connecting arms (3) are provided with a connecting rod portion (7) for joint connection; the connecting rod portion (7) comprises a base (701) and a connecting rod shaft (702), and the base (701) and the connecting rod shaft (702) are detachably fixedly connected.

3. The multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to claim 2, characterized in that: The connecting rod shaft (702) comprises a shaft sleeve (7021) sleeved on the base (701) and a limiting sleeve (7022) sleeved on the shaft sleeve (7021); the shaft sleeve (7021) is snap-connected with the base (701), and the limiting sleeve (7022) can move along the shaft sleeve (7021).

4. The multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to claim 3, characterized in that: The shaft sleeve (7021) is provided with a through hole (7023), the base (701) is provided with a groove (7011), and round balls (703) are installed on the through hole (7023) and the groove (7011); the limiting sleeve (7022) moves on the shaft sleeve (7021) through the elastic force of the elastic member (704), and the limiting sleeve (7022) is provided with an inclined surface (7024) abutting against the round ball (703).

5. The multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to claim 3, characterized in that: A clamping block (7012) is provided on the end surface of the base (701) close to the shaft sleeve (7021), and the shaft sleeve (7021) is provided with a clamping groove (7025) that cooperates with the clamping block (7012).

6. The multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to claim 2, characterized in that: The plurality of connecting arms (3) include a first connecting arm (8), a second connecting arm (9), and a third connecting arm (10) connected in sequence; the first connecting arm (8) includes a second servo (801), a first U-shaped arm (802) connected to the second servo (801), a second U-shaped arm (803), and a connecting rod portion A (71) for connecting the first U-shaped arm (802) and the second U-shaped arm (803); the second connecting arm (9) includes a third servo (901) connected to the second U-shaped arm (803), a connecting rod portion B (72) connected to the third servo (901), and a third U-shaped arm (902) connected to the connecting rod portion B (72); the third connecting arm (10) includes a fourth servo (1001) connected to the third U-shaped arm (902), and a fifth servo (1003) connected to the fourth servo (1001) via a connecting plate (1002).

7. The multi-degree-of-freedom robotic arm that can be equipped on a small or medium-sized mobile platform according to claim 2, characterized in that: The connecting rod portion (7) is provided with a through hole (705).

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