A three-degree-of-freedom spherical joint structure

Abstract

The present invention discloses a three-degree-of-freedom spherical joint structure, which includes a stationary bracket, a hemispherical rotating bracket, a semi-circular ring rotating bracket, a control board, a driving motor, a gyroscope sensor, and an output shaft bracket; the stationary bracket is used to install and fix the overall structure, the Z-axis driving motor drives the hemispherical rotating bracket to achieve Z-axis rotation, the X-axis driving motor drives the semi-circular ring rotating bracket to achieve X-axis rotation, the Y-axis driving motor drives the output shaft bracket to achieve Y-axis rotation, and an external load can be installed on the output shaft bracket. When the three motors rotate simultaneously, three-degree-of-freedom movement of the external load can be achieved. The structure of the present invention is simple, small in size, large in output torque, easy to install and maintain, and can satisfy a large three-degree-of-freedom movement range at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent robots, and particularly relates to a three-degree-of-freedom spherical joint structure. Background Art

[0002] With the continuous development and improvement of robot technology, the research on robots has increasingly become a hot spot and highlight, and higher requirements are put forward for the flexibility and reliability of robots and their moving parts. The robotic arm joint is the key to realizing the flexible movement of the robot. Therefore, it is crucial to develop a three-degree-of-freedom robotic arm joint. At present, there are multi-motor series-parallel combination schemes through transmission mechanisms for three-degree-of-freedom robotic arm joints, and there are also schemes using a single motor to execute a three-degree-of-freedom spherical motor.

[0003] Chinese Patent Document CN208961997U discloses a three-degree-of-freedom robotic arm, which realizes the movement of the robotic arm within the rated range through the series connection of three joint link assemblies, and each joint is equipped with devices such as motors, encoders, and dampers. Chinese Patent Document CN114598181A discloses a piezoelectric-driven three-degree-of-freedom spherical joint, which uses at least four two-dimensional piezoelectric actuators as the power supply mechanism, provides force and displacement / position output in the two-dimensional direction through a combined stack, and the pre-tightening device provides the required pre-tightening force through a flexible mechanism. This pre-tightening force will provide sufficient friction force for the actuator to provide the execution thrust for the spherical motion joint.

[0004] The deficiencies of the prior art are as follows: For the conventional three-degree-of-freedom joints composed of multi-motor link series-parallel combinations, in order to achieve three degrees of freedom, a large volume is required, a large amount of space is occupied, the integration level is low, and at the same time, the structure is complex and the cost is high; while for single-motor or non-motor three-degree-of-freedom joints, most of them are still in the laboratory experiment stage, with small output torque, and at the same time, high requirements are placed on the structural design accuracy and sensing equipment, the processing difficulty is large, and the cost is high. Summary of the Invention

[0005] To overcome the deficiencies of the prior art, the present invention provides a three-degree-of-freedom spherical joint structure to solve the problems of complex structure, low integration level, large volume, small output torque, difficult processing, and difficult installation and maintenance of traditional three-degree-of-freedom robotic arm joints.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A three-degree-of-freedom spherical joint structure comprises a stationary bracket for overall fixing, a hemispherical rotating bracket for realizing Z-axis rotation, a semicircular ring rotating bracket for realizing X-axis rotation, an output shaft bracket, a control board, a Z-axis driving motor, a Y-axis driving motor, an X-axis driving motor and a gyroscope sensor; one side of the hemispherical rotating bracket is connected to the stationary bracket along the Z-axis, and the other side is connected to the stationary bracket through the Z-axis driving motor; one side of the semicircular ring rotating bracket is connected to the hemispherical rotating bracket along the X-axis, and the other side is connected to the hemispherical rotating bracket through the X-axis driving motor; the Y-axis driving motor is arranged at the center of the semicircular ring rotating bracket, and the output shaft bracket is arranged on the Y-axis driving motor; the gyroscope sensor is installed in the output shaft bracket; the control board is arranged in the heat dissipation slot of the stationary bracket, and is used to control the operation of the Z-axis driving motor, the Y-axis driving motor and the X-axis driving motor; an external load is installed on the upper end of the output shaft bracket, and when the Z-axis driving motor, the Y-axis driving motor and the X-axis driving motor rotate simultaneously, the three-degree-of-freedom movement of the external load is realized.

[0008] Furthermore, the stationary bracket is designed to be in a hemispherical shape and is fixed to the external structure via a bottom plane; the heat dissipation groove dissipates the heat generated by the control panel to the external space.

[0009] Furthermore, the hemispherical rotating bracket is designed into a hemispherical shape and is connected to the stationary bracket through bearings, rotating shafts, retaining rings, and bolts. The operation of the Z-axis driving motor drives the hemispherical rotating bracket to rotate around the Z-axis, and the motion range exceeds 90°.

[0010] Furthermore, the semicircular ring rotating bracket is designed in a semicircular ring shape and is connected to the hemispherical rotating bracket through bearings, rotating shafts, retaining rings, and bolts. The operation of the X-axis driving motor drives the semicircular ring rotating bracket to rotate around the X-axis, and the motion range exceeds 90°.

[0011] Furthermore, the operation of the Y-axis driving motor drives the external load to rotate around the Y-axis, and the motion range exceeds 360°.

[0012] Furthermore, the Z-axis drive motor, the Y-axis drive motor, and the X-axis drive motor are stepping motors, DC drive motors, or servo motors.

[0013] Furthermore, the Z-axis drive motor, the Y-axis drive motor, and the X-axis drive motor are servo harmonic reduction motors with built-in temperature sensors, torque sensors, encoders, brakes, and reducers.

[0014] Furthermore, the gyro sensor realizes data fusion with encoders inside the Z-axis drive motor, the Y-axis drive motor, and the X-axis drive motor, so as to calibrate the position of the external load.

[0015] Further, the gyroscope sensor is a six-axis or nine-axis type.

[0016] The beneficial effects of the present invention are as follows:

[0017] (1) The present invention realizes the three-degree-of-freedom movement of the joint through three driving motors and a novel spherical structure, with a simple and compact structure, small volume, capable of meeting a large movement range, and facilitating installation and maintenance;

[0018] (2) The present invention adopts an integrated driving motor, with built-in sensors, encoders, brakes and speed reducers, effectively realizing stable operation at low speeds, having a large output torque, strong self-locking ability, accurate positioning, simplifying the structure, and reducing the volume and weight of the three-degree-of-freedom joint; Description of the Drawings

[0019] Figure 1 is the overall assembly drawing of the three-degree-of-freedom spherical joint structure of the present invention;

[0020] Figure 2 is the sectional view of the ZOY plane of the three-degree-of-freedom spherical joint structure of the present invention;

[0021] Figure 3 is Figure 1 the structural drawing of the hemispherical rotating bracket in

[0022] In the figure: 1 is the stationary bracket; 2 is the hemispherical rotating bracket; 3 is the semi-circular ring rotating bracket; 4 is the output shaft bracket; 5 is the control board; 6 is the Z-axis driving motor; 7 is the Y-axis driving motor; 8 is the X-axis driving motor; 9 is the gyroscope sensor; 11 is the heat dissipation groove. Detailed Embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] As Figure 1 shown, a three-degree-of-freedom spherical joint structure of the present invention includes a stationary bracket 1 for overall fixation, a hemispherical rotating bracket 2 for realizing Z-axis rotation, a semi-circular ring rotating bracket 3 for realizing X-axis rotation, and an output shaft bracket 4. The three degrees of freedom are the X, Y, and Z directions. The bottom surface of the stationary bracket 1 is defined as the XOZ plane, and the axis perpendicular to it is the Y axis. The stationary bracket 1 is designed in a hemispherical shape, with the smallest volume under the premise of realizing the three-degree-of-freedom movement range, and its bottom is designed as a plane, through which it can be fixed to the external structure through the bottom plane.

[0025] like Figure 2 As shown, the control board 5 is placed in the heat dissipation slot 11 of the stationary bracket 1, and the heat generated by the control board 5 is dissipated to the external space through the heat dissipation slot 11, which effectively solves the overheating problem of the control board 5 during long-term operation; the control board 5 is used to control the operation of the Z-axis drive motor 6, the Y-axis drive motor 7 and the X-axis drive motor 8.

[0026] like Figure 2 As shown in FIG. 3 , the hemispherical rotating bracket 2 is designed to be hemispherical in shape, with a diameter slightly smaller than that of the stationary bracket 1. A waist-shaped groove is opened along the YOZ plane to meet the rotation range of the semicircular rotating bracket 3; the hemispherical rotating bracket 2 is connected to the stationary bracket 1 along the Z axis and can rotate around the Z axis with a motion range of more than 90°. One side is connected to the stationary bracket 1 through a bearing, a rotating shaft, a retaining ring, and a bolt. The stator of the Z-axis driving motor 6 is connected to the stationary bracket 1 to fix the motor, and the rotor of the Z-axis driving motor 6 is connected to the hemispherical rotating bracket 2. The operation of the Z-axis driving motor 6 drives the hemispherical rotating bracket 2 to rotate around the Z axis.

[0027] like Figure 2 As shown, the semicircular ring-shaped rotating bracket 3 is designed to be in a semicircular shape and is designed to be a cylindrical surface along the Y-axis direction to realize the installation of the Y-axis drive motor 7. Support porous ribs are designed on both sides. Through software optimization, the semicircular ring-shaped rotating bracket 3 can not only achieve the strength and rigidity of the bearing motor, but also reduce the weight of the bracket to the greatest extent; the semicircular ring-shaped rotating bracket 3 is connected to the hemispherical rotating bracket 2 along the X-axis, and can rotate around the X-axis with a motion range of more than 90°. One side is connected to the hemispherical rotating bracket 2 through a bearing, a rotating shaft, a retaining ring, and a bolt. The stator of the X-axis drive motor 8 is connected to the hemispherical rotating bracket 2 to fix the motor, and the rotor of the X-axis drive motor 8 is connected to the semicircular ring-shaped rotating bracket 3. The operation of the X-axis drive motor 8 drives the semicircular ring-shaped rotating bracket 3 to rotate around the X-axis.

[0028] The output shaft bracket 4 is placed on the Y-axis drive motor 7. An external load can be installed on the upper end of the output shaft bracket 4, which can rotate around the Y-axis with a motion range of more than 360°. When the three-axis drive motors rotate simultaneously, three-degree-of-freedom motion of the external load can be achieved.

[0029] The X, Y, Z axis drive motors 6, 7, 8 can be any one of a stepper motor, a DC drive motor, and a servo motor, preferably a servo harmonic reduction motor, with built-in temperature sensor, torque sensor, encoder, brake and reducer. Therefore, when the spherical joint structure is powered off as a whole, the built-in brake of the drive motor can keep the output shaft position of the spherical joint structure unchanged.

[0030] like Figure 2As shown, the gyroscope sensor 9 is installed inside the output shaft bracket 4 and can achieve data fusion with the encoders inside the Z-axis drive motor 6, Y-axis drive motor 7, and X-axis drive motor 8 for calibrating the position of an external load.

[0031] The gyroscope sensor 9 can be of any type such as six-axis or nine-axis, and preferably a nine-axis type is suitable.

[0032] Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-degree-of-freedom spherical joint structure, characterized in that: It includes a stationary bracket (1) for overall fixation, a hemispherical rotating bracket (2) for realizing Z-axis rotation, a semi-circular ring rotating bracket (3) for realizing X-axis rotation, an output shaft bracket (4), a control board (5), a Z-axis driving motor (6), a Y-axis driving motor (7), an X-axis driving motor (8), and a gyroscope sensor (9); one side of the hemispherical rotating bracket (2) is connected to the stationary bracket (1) along the Z-axis, and the other side is connected to the stationary bracket (1) through the Z-axis driving motor (6); one side of the semi-circular ring rotating bracket (3) is connected to the hemispherical rotating bracket (2) along the X-axis, and the other side is connected to the hemispherical rotating bracket (2) through the X-axis driving motor (8); the Y-axis driving motor (7) is arranged at the center of the semi-circular ring rotating bracket (3), and the output shaft bracket (4) is arranged on the Y-axis driving motor (7); the gyroscope sensor (9) is installed inside the output shaft bracket (4); the control board (5) is arranged in the heat dissipation groove (11) of the stationary bracket (1) to control the operation of the Z-axis driving motor (6), Y-axis driving motor (7), and X-axis driving motor (8); an external load is installed at the upper end of the output shaft bracket (4), and when the Z-axis driving motor (6), Y-axis driving motor (7), and X-axis driving motor (8) rotate simultaneously, three-degree-of-freedom movement of the external load is realized; the operation of the X-axis driving motor (8) drives the semi-circular ring rotating bracket (3) to rotate around the X-axis, and the movement range exceeds 90°; the operation of the Y-axis driving motor (7) drives the external load to rotate around the Y-axis, and the movement range exceeds 360°; three-degree-of-freedom movement of the joint is realized through three driving motors and a new spherical structure.

2. The three-degree-of-freedom spherical joint structure according to claim 1, characterized in that: The stationary bracket (1) is designed in a hemispherical shape and is fixed to the external structure through the bottom plane; the heat dissipation groove dissipates the heat generated by the control board to the external space.

3. The three-degree-of-freedom spherical joint structure according to claim 1, characterized in that: The hemispherical rotating bracket (2) is designed in a hemispherical shape and is connected to the stationary bracket (1) through bearings, rotating shafts, retaining rings, and bolts. The operation of the Z-axis driving motor (6) drives the hemispherical rotating bracket (2) to rotate around the Z-axis, and the movement range exceeds 90°.

4. The three-degree-of-freedom spherical joint structure according to claim 1, characterized in that: The semi-circular ring rotating bracket (3) is designed in a semi-circular ring shape and is connected to the hemispherical rotating bracket (2) through bearings, rotating shafts, retaining rings, and bolts.

5. The three-degree-of-freedom spherical joint structure according to claim 1, wherein: The Z-axis driving motor (6), Y-axis driving motor (7), and X-axis driving motor (8) are stepper motors, DC driving motors, or servo motors.

6. The three-degree-of-freedom spherical joint structure according to claim 1, wherein: The Z-axis driving motor (6), Y-axis driving motor (7), and X-axis driving motor (8) are servo harmonic reduction motors, with built-in temperature sensors, torque sensors, encoders, brakes, and speed reducers.

7. The three-degree-of-freedom spherical joint structure according to claim 6, wherein: The gyroscope sensor (9) realizes data fusion with the encoders inside the Z-axis driving motor (6), Y-axis driving motor (7), and X-axis driving motor (8) for calibrating the position of the external load.

8. The three-degree-of-freedom spherical joint structure according to claim 1, characterized in that: The gyroscope sensor (9) is six-axis or nine-axis.

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