A dual-motor parallel structure mechanical arm and a control method thereof

Abstract

The application relates to the technical field of robots, and particularly discloses a mechanical arm with a double-motor parallel structure, which comprises a fixing base, a telescopic lifting mechanism arranged on the fixing base, two transmission assemblies, vertical sliding rails, horizontal sliding rails, slide rods, first motors and belts, lifting sliding blocks slidably arranged on the vertical sliding rails, first belt pulleys and second belt pulleys arranged at the two ends of the horizontal sliding rails respectively, the middle portions of the slide rods in sliding fit with the horizontal sliding rails, lifting limit blocks arranged at the top portions of the vertical sliding rails of the two transmission assemblies, and horizontal limit blocks fixedly connected at the two ends of the horizontal slide rods of the two transmission assemblies, wherein one of the horizontal limit blocks is provided with a clamping mechanism for clamping an object. The application further discloses a control method of the mechanical arm with the double-motor parallel structure. The mechanical arm with the double-motor parallel structure and the control method thereof are simple in structure, convenient to control, convenient to disassemble and assemble, and easy to maintain.

Description

Technical Field

[0001] This invention relates to the field of robotics, and in particular to a robotic arm with a dual-motor parallel structure and its control method. Background Technology

[0002] Robotic arms are widely used in various robotics fields such as construction, medical, transportation, industry, and service. Currently, traditional robotic arms are divided into serial robotic arms and parallel robotic arms. Serial robotic arms have an open structure, where the position and attitude information of the robotic arm are calculated by inverse calculation based on its motion equations. Their advantages include a large operating range and good flexibility. However, due to the open working mode, there will be accumulated errors, which need to be eliminated periodically. Furthermore, their serial structure requires inverse calculation of the position and attitude information of each joint step by step, making them difficult to adapt to fast and high-precision grasping tasks. Parallel robotic arms have a closed structure with multiple arm segments (three or more) directly driven connections. They can share the load, are more stable, and are suitable for high-precision control. However, the coupling structure of multiple arm segments results in a large amount of motion control programming, making structural maintenance work extensive and complex. Summary of the Invention

[0003] This invention aims to solve at least one of the aforementioned technical problems by providing a robotic arm with a dual-motor parallel structure and its control method. The robotic arm's telescopic lifting mechanism is composed of only two integrated motors. By controlling the two motors to move in the same or opposite directions, the telescopic lifting mechanism can move up and down in the vertical direction and forward and backward in the horizontal direction. In addition, a horizontal rotation mechanism is added to drive the telescopic lifting mechanism to rotate 360° in the horizontal direction, thereby enabling the robotic arm to achieve three-dimensional motion adjustment in the XYZ directions. The structure is simple, easy to operate, easy to disassemble and assemble, and easy to maintain.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a robotic arm with a dual-motor parallel structure, comprising a fixed base and a telescopic lifting mechanism mounted on the fixed base. The telescopic lifting mechanism includes two transmission components, each including a vertical slide rail, a horizontal slide rail, a slide rod, a first motor, a belt, and a lifting slider. The vertical slide rail is mounted on the fixed base, and the lifting slider is slidably mounted on the vertical slide rail. The horizontal slide rail is fixedly mounted on the lifting slider. A first pulley and a second pulley are respectively provided at both ends of the horizontal slide rail. The middle part of the slide rod slides in cooperation with the horizontal slide rail. A lifting limit block is provided at the top of the vertical slide rail of both transmission components, and the two ends of the horizontal slide rod of the two transmission components are fixedly connected by the horizontal limit blocks. The first transmission component has a horizontal limiting block equipped with a clamping mechanism for holding objects, a lifting limiting block equipped with a third pulley, and an output shaft of the first motor equipped with a fourth pulley. One end of the belt of one transmission component is fixedly connected to the horizontal limiting block equipped with the clamping mechanism, and the other end passes sequentially around the bottom of the first pulley, the top of the third pulley, the bottom of the fourth pulley, and the top of the second pulley, and is fixedly connected to another horizontal limiting block. One end of the belt of another transmission component is fixedly connected to the horizontal limiting block equipped with the clamping mechanism, and the other end passes sequentially around the top of the first pulley, the bottom of the fourth pulley, the top of the third pulley, and the bottom of the second pulley, and is fixedly connected to another horizontal limiting block.

[0005] Preferably, it also includes a horizontal rotating mechanism mounted on a fixed base, a telescopic lifting mechanism mounted on the horizontal rotating mechanism, and the horizontal rotating mechanism is capable of driving the telescopic lifting mechanism to rotate 360° in the horizontal direction.

[0006] Preferably, the horizontal rotation mechanism includes a turntable and a second motor. The turntable is rotatably connected to the fixed base. The vertical slide rails of the two transmission components are symmetrically fixed on opposite sides of the turntable. The second motor and the turntable can drive the turntable to rotate relative to the fixed base.

[0007] Preferably, the turntable is annular, and the outer edge of the turntable is rotatably engaged with the fixed seat via ball bearings.

[0008] Preferably, a connecting sleeve is fixedly installed on the output shaft of the second motor, and the connecting sleeve is fixedly connected to the bottom of the turntable through a connecting rod.

[0009] Preferably, the fixed base is equipped with fixed support legs.

[0010] Preferably, the clamping mechanism includes a third motor and two clamping arms. One end of each clamping arm is rotatably connected to a horizontal limiting block and is provided with a gear meshing part. The third motor is connected to the gear meshing part of the two clamping arms through a transmission gear, so as to drive the two clamping arms to move towards or away from each other.

[0011] This application also discloses a control method for a robotic arm with a dual-motor parallel structure. Using the aforementioned robotic arm, the method includes the following steps: A zero-motion control command is sent from the control center. Upon receiving the command, the motor control system controls the two first motors to rotate in opposite directions, returning the gripping mechanism to its zero point in the Y direction. Next, the motor control system controls the two first motors to rotate in the same direction, returning the gripping mechanism to its zero point in the X direction, thus achieving zero-motion operation of the gripping mechanism's planar motion in the XY direction. Then, the control center sends a control command to the motor control system to reach the desired position in the XY direction. First, the motor control system controls the two first motors to rotate in the same direction to reach the X-direction position point. Then, the motor control system controls the two first motors to rotate in opposite directions to reach the Y-direction position point, allowing the gripping mechanism to move to the designated position. Finally, the two first motors are shut off. If the robotic arm is equipped with a horizontal rotation mechanism, a control command to reach the desired position in the Z direction is sent from the control center to the motor control system. The motor control system then controls the second motor to rotate, causing the entire telescopic lifting mechanism to rotate horizontally, thus rotating the gripping mechanism to the designated position.

[0012] The beneficial effects are as follows: Compared with the prior art, the robotic arm and its control method with a dual-motor parallel structure of the present invention achieve the same motion function of multiple arm segments through the use of a dual-motor parallel structure robotic arm structure. It has the advantages of high stability, high speed and high precision, and simple structure. At the same time, the motion control of the robotic arm structure with dual-motor parallel structure only requires simple same-direction or reverse control, the motion control program is small, and the parts have good versatility, are easy to install and dismantle, and are easy to maintain. Attached Figure Description

[0013] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of a robotic arm with a dual-motor parallel structure according to the present invention, taken from one perspective. Figure 2 This is a schematic diagram of the structure of a robotic arm with a dual-motor parallel structure according to the present invention from another perspective. Figure 3 This is a schematic diagram of the installation structure of the telescopic lifting mechanism; Figure 4 This is a schematic diagram of the clamping mechanism; Figure 5 This is a schematic diagram of the control hardware for a robotic arm with a dual-motor parallel structure according to the present invention; Figure 6 This is a flowchart of the zero-reset operation control for a robotic arm with a dual-motor parallel structure according to the present invention; Figure 7 This is a flowchart illustrating the working control of a robotic arm with a dual-motor parallel structure according to the present invention. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0015] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a central component. When a component is described as "connected to" another component, it can be directly connected to the other component or may have a central component. When a component is described as "set on" another component, it can be directly set on the other component or may have a central component. When a component is described as "set in the middle," it is not simply set in the exact center, as long as it is not set within the area defined by both ends being in the middle. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] like Figures 1 to 4As shown, this application discloses a robotic arm with a dual-motor parallel structure, including a fixed base 1 and a telescopic lifting mechanism mounted on the fixed base 1. The fixed base 1 can be equipped with fixed legs 17, facilitating its installation on other motion platforms. The telescopic lifting mechanism includes two transmission components, each comprising a vertical slide rail 2, a horizontal slide rail 3, a slide rod 4, a first motor 5, a belt 6, and a lifting slider 7. The vertical slide rail 2 is mounted on the fixed base 1, and the lifting slider 7 is slidably mounted on the vertical slide rail 2. The horizontal slide rail 3 is fixedly mounted on the lifting slider 7. A first pulley 8 and a second pulley 9 are respectively provided at both ends of the horizontal slide rail 3. The middle part of the slide rod 4 slides in cooperation with the horizontal slide rail 3. A lifting limit block 10 is provided at the top of the vertical slide rail 2 of both transmission components. The two ends of the horizontal slide rod 4 of both transmission components are fixedly connected by horizontal limit blocks 11. One horizontal limit block 11 is equipped with a clamping mechanism 12 for clamping objects, and a third belt is mounted on the lifting limit block 10. A fourth pulley 14 is mounted on the output shaft of the first motor 5. One end of the belt 6 of one transmission component is fixedly connected to a horizontal limiting block 11 with a clamping mechanism 12, and the other end passes sequentially around the lower part of the first pulley 8, the upper part of the third pulley 13, the lower part of the fourth pulley 14, and the upper part of the second pulley 9, and is fixedly connected to another horizontal limiting block 11. One end of the belt 6 of the other transmission component is fixedly connected to a horizontal limiting block 11 with a clamping mechanism 12, and the other end passes sequentially around the upper part of the first pulley 8, the lower part of the fourth pulley 14, the upper part of the third pulley 13, and the lower part of the second pulley 9, and is fixedly connected to another horizontal limiting block 11. In this embodiment, the first pulley 8 is closer to the clamping mechanism 12 than the second pulley 9. By adopting the above-mentioned winding mechanism, the belts 6 of the two transmission components can form a horizontal transmission section and a vertical transmission section, thereby enabling the horizontal slide bar 4 to move in both the horizontal and vertical directions.

[0018] In one preferred embodiment of this application, the robotic arm further includes a horizontal rotation mechanism mounted on a fixed base 1, and a telescopic lifting mechanism mounted on the horizontal rotation mechanism. The horizontal rotation mechanism can drive the telescopic lifting mechanism to rotate 360° in the horizontal direction, so that the robotic arm structure of this application can realize rotational adjustment in the horizontal direction, and the robotic arm has an additional Z-axis degree of freedom.

[0019] Specifically, the horizontal rotation mechanism includes a turntable 15 and a second motor 16. The turntable 15 is rotatably connected to the fixed base 1. The vertical slide rails 2 of the two transmission components are symmetrically fixed on opposite sides of the turntable 15. The second motor 16 and the turntable 15 can drive the turntable 15 to rotate relative to the fixed base 1, thereby adjusting the rotation angle of the turntable 15 by controlling the rotation of the second motor 16. In this embodiment, the turntable 15 can be annular, and the outer edge of the turntable 15 can be rotatably engaged with the fixed base 1 through ball bearings. Specifically, the center of the fixed base 1 can be provided with a circular hole for mounting the turntable 15. The wall of the circular hole can be provided with a mounting groove, and ball bearings are installed in the mounting groove. By rolling the outer edge of the turntable 15 with the ball bearings, the rotational connection between the turntable 15 and the fixed base 1 is realized.

[0020] More specifically, a connecting sleeve 18 can be fixedly installed on the output shaft of the second motor 16. The connecting sleeve 18 is fixedly connected to the bottom of the turntable 15 via a connecting rod 19. The connecting rod 19 is L-shaped, with one end fixedly connected to the connecting sleeve 18 and the other end fixedly connected to the bottom of the turntable 15. During installation, the second motor 16 is fixedly installed on the equipment or on the fixed base 1. The second motor 16 drives the connecting rod 19 to rotate, thereby causing the turntable 15 to rotate 360° relative to the fixed base 1 in the horizontal direction. Fixed support feet 17 are installed on the fixed base 1.

[0021] In another specific embodiment of this application, the clamping mechanism 12 may include a third motor 20 and two clamping arms 21. One end of each clamping arm 21 is rotatably connected to a horizontal limiting block 11 and is provided with a gear meshing part 22. The third motor 20 is driven to drive the two clamping arms 21 to move towards or away from each other through a transmission gear. Specifically, a mounting plate is provided on the horizontal limiting block 11, and the third motor 20 is fixedly mounted on the mounting plate. An active gear is mounted on the output shaft of the third motor 20. The wheel 23 and one end of the two clamping arms 21 are rotatably connected to the mounting plate via a rotating shaft. Two gear meshing parts 22 are installed on one of the clamping arms 21. The driving gear 23 is connected to one of the gear meshing parts 22 of one of the clamping arms 21, and the other gear meshing part 22 of the clamping arm 21 is connected to the gear meshing part 22 of the other clamping arm 21. By controlling the third motor 20 to rotate in the forward or reverse direction, the two clamping arms 21 can be driven to move towards or away from each other to clamp the object or release the clamped object.

[0022] In addition, such as Figures 5 to 7As shown, this application also discloses a control method for a robotic arm with a dual-motor parallel structure. Using the aforementioned robotic arm, the method includes the following steps: The robotic arm automatically returns to zero upon startup. A zero-return motion control command is sent through the control center. Upon receiving the command, the motor control system controls the two first motors 5 to rotate in opposite directions, driving the clamping mechanism 12 upwards along the vertical slide rail 2 until the lifting slider 7 abuts against the lifting limit block 10, causing the clamping mechanism 12 to return to the zero point in the Y direction. Next, the motor control system controls the two first motors 5 to rotate in the same direction, causing the slide bar 4 to drive the clamping mechanism 12 to move along the horizontal slide rail 3 until the horizontal limit block 11 abuts against the end of the horizontal slide rail 3, causing the clamping mechanism 12 to return to the zero point in the X direction, thus achieving zero-return planar motion of the clamping mechanism 12 in the XY direction. If the robotic arm is equipped with a horizontal rotation mechanism, a zero-return control command for the Z-direction position is sent to the motor control system through the control center. The motor control system then controls the second motor 16 to rotate, driving the entire telescopic lifting mechanism back to the designated zero point position. The control center and the motor control system are connected via a common industrial CAN or RS485 bus. If a fault occurs during the zeroing process, exceeding its safe operating range, the control center enters its fault diagnosis mode and takes over its operation to ensure the controllability and safety of the robotic arm. After the robotic arm achieves the zeroing operation, it enters the normal control mode. The control center sends control commands to the motor control system to reach the X and Y positions. First, the motor control system controls the two first motors 5 to rotate in the same direction to reach the X position point. Then, the motor control system controls the two first motors 5 to rotate in the opposite direction to reach the Y position point, so that the gripping mechanism 12 moves to the designated position. Finally, the two first motors 5 are turned off. If the robotic arm is equipped with a horizontal rotation mechanism, the control center sends control commands to the motor control system to reach the Z position. The motor control system controls the second motor 16 to rotate, driving the entire telescopic lifting mechanism to rotate horizontally, so that the gripping mechanism 12 rotates to the designated position.

[0023] Therefore, the robotic arm and its control method with a dual-motor parallel structure of the present invention achieve the same motion function of multiple arm segments through two arm segments by adopting a dual-motor parallel structure robotic arm structure. It has the advantages of high stability, high speed and high precision, and simple structure. At the same time, the motion control of the robotic arm structure with dual-motor parallel structure only requires simple same-direction or reverse control, the motion control program is small, the parts have good versatility, and it is easy to install, disassemble and maintain.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the technical solutions of the present invention.

Claims

1. A robotic arm with a dual-motor parallel structure, characterized in that, The system includes a fixed base (1), and a telescopic lifting mechanism and a horizontal rotation mechanism mounted on the fixed base (1). The telescopic lifting mechanism includes two transmission components, each of which includes a vertical slide rail (2), a horizontal slide rail (3), a slide rod (4), a first motor (5), a belt (6), and a lifting slider (7). The vertical slide rail (2) is mounted on the fixed base (1), and the lifting slider (7) is slidably mounted on the vertical slide rail (2). The horizontal slide rail (3) is fixedly mounted on the lifting slider (7), and a first pulley (8) and a horizontal pulley (7) are respectively provided at both ends of the horizontal slide rail (3). The second pulley (9), the middle part of the slide bar (4) slides in cooperation with the horizontal slide rail (3), the top of the vertical slide rail (2) of both transmission components is provided with a lifting limit block (10), the two ends of the horizontal slide bar (4) of the two transmission components are fixedly connected by a horizontal limit block (11), one of the horizontal limit blocks (11) is provided with a clamping mechanism (12) for clamping objects, the lifting limit block (10) is equipped with a third pulley (13), the output shaft of the first motor (5) is equipped with a fourth pulley (14), and the belt (6) of one of the transmission components One end of the belt (6) of the other transmission component is fixedly connected to the horizontal limiting block (11) provided with the clamping mechanism (12), and the other end passes successively around the bottom of the first pulley (8), the top of the third pulley (13), the bottom of the fourth pulley (14), and the top of the second pulley (9), and is fixedly connected to another horizontal limiting block (11). One end of the belt (6) of the other transmission component is fixedly connected to the horizontal limiting block (11) provided with the clamping mechanism (12), and the other end passes successively around the top of the first pulley (8), the bottom of the fourth pulley (14), and the third pulley (13). Above the second pulley (9) and below it, and fixedly connected to another horizontal limiting block (11); the telescopic lifting mechanism is installed on the horizontal rotating mechanism, and the horizontal rotating mechanism can drive the telescopic lifting mechanism to rotate 360° in the horizontal direction; the horizontal rotating mechanism includes a turntable (15) and a second motor (16), the turntable (15) is rotatably connected to the fixed seat (1), the vertical slide rails (2) of the two transmission components are symmetrically fixed on opposite sides of the turntable (15), and the second motor (16) can drive the turntable (15) to rotate relative to the fixed seat (1).

2. The robotic arm with a dual-motor parallel structure according to claim 1, characterized in that, The turntable (15) is annular, and the outer edge of the turntable (15) is rotatably engaged with the fixed seat (1) by ball bearings.

3. The robotic arm with a dual-motor parallel structure according to claim 1, characterized in that, A connecting sleeve (18) is fixedly installed on the output shaft of the second motor (16), and the connecting sleeve (18) is fixedly connected to the bottom of the turntable (15) through the connecting rod (19).

4. The robotic arm with a dual-motor parallel structure according to claim 1, characterized in that, The fixed base (1) is equipped with a fixed support leg (17).

5. A robotic arm with a dual-motor parallel structure according to claim 1, characterized in that, The clamping mechanism (12) includes a third motor (20) and two clamping arms (21). One end of the two clamping arms (21) is rotatably connected to the horizontal limiting block (11) and is provided with a gear meshing part (22). The third motor (20) is connected to the gear meshing part (22) of the two clamping arms (21) through a transmission gear, so as to drive the two clamping arms (21) to move towards each other or away from each other.

6. A control method for a robotic arm with a dual-motor parallel structure, characterized in that, The robotic arm described in any one of claims 1-5 includes the following steps: a zero-motion control command is sent through the control center. After receiving the command, the motor control system controls the two first motors (5) to rotate in opposite directions, so that the gripping mechanism (12) returns to the zero point in the Y direction. Then, the motor control system controls the two first motors (5) to rotate in the same direction, so that the gripping mechanism (12) returns to the zero point in the X direction, thereby realizing the zero-motion operation of the planar motion of the gripping mechanism (12) in the XY direction. Next, the control center sends a control command to the motor control system to reach the position in the XY direction. First, the motor control system controls the two first motors (5) to rotate in the same direction to reach the position point in the X direction. Then, the motor control system controls the two first motors (5) to rotate in opposite directions to reach the position point in the Y direction, so that the gripping mechanism (12) moves to the designated position to work. Finally, the two first motors (5) are controlled to shut down.

Images