Multi-degree-of-freedom robot end execution platform and control method

Abstract

The application discloses a multi-degree-of-freedom robot end execution platform and a control method thereof. The platform comprises a base, a screw rod motor arranged at the middle of the upper end of the base, a screw rod arranged on the output end of the screw rod motor, a lifting platform arranged above the base, a screw rod nut arranged at the middle of the lifting platform and screwed with the screw rod, the screw rod penetrating through the screw rod nut and being rotationally connected with a support seat arranged at the upper end of the lifting platform, an end platform connected with the middle of the support seat through a spherical hinge structure, at least two electric telescopic rods arranged between the end platform and the support seat, one end of each electric telescopic rod connected with the end platform through a flexible rubber ball head hinge structure and the other end of each electric telescopic rod fixed on the support seat. The control method comprises steps S1-S4. The multi-direction force sensing unit, the spring assembly and the linear guide mechanism are cooperative, can buffer instantaneous force fluctuation, limit excessive posture deviation, avoid scratching workpieces (polishing scene) or falling off (grabbing scene) of the execution end, and improve operation stability.

Description

Technical Field

[0001] This invention relates to the field of robot platforms, and more specifically to a multi-degree-of-freedom robot end effector platform and control method. Background Technology

[0002] In existing technologies, multi-degree-of-freedom end effectors not only suffer from insufficient force control precision, poor adaptability, difficulty in eliminating mechanical vibration, and overly complex and bulky structures, but also generally lack the ability to sense independent forces in multiple directions and coordinate attitude adjustment. When grinding curved surfaces or grasping irregular workpieces, they can only achieve force control in a single direction (such as the vertical direction). It is difficult to correct the tension fluctuations and attitude deviations in the front-back / left-right directions in real time, which can easily lead to scratches on the workpiece surface (grinding scenario) or the workpiece falling off (grabbing scenario). Moreover, traditional attitude adjustment relies on high-frequency intervention from the host computer, which results in a delayed response and further reduces the stability of the operation. Summary of the Invention

[0003] In view of the above-mentioned shortcomings of the prior art, the present invention provides a multi-degree-of-freedom robot end effector platform and control method, which solves the defects of inaccurate posture perception and low control precision in the prior art.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A multi-degree-of-freedom robot end effector platform is provided, comprising a base, a lead screw motor disposed at the upper middle of the base, a lead screw disposed at the output end of the lead screw motor, a lifting platform disposed above the base, a lead screw nut disposed in the middle of the lifting platform and engaging with the lead screw, the lead screw passing through the lead screw nut and rotatably connected to a support seat disposed at the upper end of the lifting platform, an end effector platform being connected to the middle of the support seat via a ball joint structure, at least two electric telescopic rods disposed between the end effector platform and the support seat, one end of the electric telescopic rod being connected to the end effector platform via a flexible rubber ball joint structure, and the other end being fixed to the support seat, and the two electric telescopic rods being distributed at a 90° angle in the circumferential direction.

[0005] Furthermore, at least four first springs are provided on the end platform. The four first springs are evenly distributed in the axial direction and are located on the outside of the support base. The two ends of two of the first springs are connected to the end platform and the base through spring connectors. One end of the other two first springs is connected to the end platform through a spring connector, and the other end is connected to the base through a tension sensor. The two tension sensors are distributed at 90° in the circumferential direction. The lifting platform has through holes for the first springs to pass through.

[0006] Furthermore, several sliding rods are arranged around the lead screw motor, a first sliding sleeve that slides and engages with the sliding rods is provided on the lifting platform, and a second sliding sleeve that slides and engages with the sliding rods is provided on the base.

[0007] Furthermore, the base is a hollow structure, and a shock-absorbing base is provided at the bottom of the base. The slide rod passes through the base and is connected to the shock-absorbing base. A second spring is provided between the second slide sleeve and the shock-absorbing base, and the second spring is sleeved on the slide rod.

[0008] Furthermore, an electrode spring is provided inside the base, and a pressure plate is provided at the end of the electrode spring. A piezoelectric ceramic electrode sheet that cooperates with the pressure plate is provided inside the shock-absorbing base, and the piezoelectric ceramic electrode sheet is located in a limiting ring provided inside the shock-absorbing base.

[0009] Furthermore, the flexible rubber ball joint structure includes a universal ball joint and a spherical cup structure. The universal ball joint is mounted on the electric telescopic rod and is movably mounted inside the spherical cup structure. The internal space dimension of the spherical cup structure is larger than the dimension of the universal ball joint. An elastic rubber pad is provided at the bottom of the spherical cup structure. The universal ball joint abuts against the elastic rubber pad to provide freedom during electric telescopic movement.

[0010] Furthermore, a mating ring is provided at the upper end of the damping base. The outer diameter of the mating ring is smaller than the outer diameter of the damping base, so that a step is formed between the mating ring and the damping base. The mating ring is inserted into the lower end of the base.

[0011] A control method for the aforementioned multi-degree-of-freedom robot end effector platform is provided, comprising the following steps: S1: During operation, the end platform tilts in different directions by extending and retracting two electric telescopic rods. The universal ball joint of the flexural rubber ball joint structure rotates adaptively, while the elastic rubber pad layer deforms adaptively, ensuring that the end platform can deflect freely. S2: Two tension sensors collect the tension of the first spring in real time, and construct a relationship between the tension of the first spring and the tilt angle of the end platform in that direction. The conversion formula; ; in, For the current moment t The tension data collected by the tension sensor The tension data collected by the tension sensor in the initial state of the first spring. k Let be the stiffness coefficient of the first spring. The straight-line distance between the spherical hinge structure and the first spring; S3: The robot plans the tilt angle of the end effector platform in different directions according to the execution instructions, inputs it into the conversion formula, and calculates the tension force of the first spring on the tension sensor after the end effector platform moves into position. , T To determine the planned motion time, the tension sensor collects tension data in real time during the end-effector's movement until the tension is reached. After that, the electric telescopic pole stopped extending and retracting; S4: The electrode spring, together with the pressure plate, compresses the piezoelectric ceramic electrode sheet, and collects the vertical force in real time to obtain the load data of the robot end effector platform. When the load data exceeds the set threshold, an alarm is issued to prevent the robot end effector platform from being overloaded.

[0012] The beneficial effects of this invention are as follows: As an end effector platform for robots, this invention is particularly suitable for industrial robot applications. It enables the end effector platform to perform only deflection and movement in the left-right, forward-backward, and vertical directions, with independent sensing and control of movement in each direction, adapting to complex scenarios such as curved surface grinding and irregular workpiece gripping. The multi-directional force sensing unit, in conjunction with the spring assembly and linear guide mechanism, can buffer instantaneous force fluctuations, limit excessive posture deviations, and prevent the end effector from scratching the workpiece (grinding scenario) or causing it to fall off (grinding scenario), thus improving operational stability. Attached Figure Description

[0013] Figure 1 A 3D view of a multi-degree-of-freedom robot end effector platform.

[0014] Figure 2 This is a diagram of the internal structure of the base.

[0015] Figure 3 This is a structural diagram showing the fit between the base and the shock-absorbing base.

[0016] Among them, 1. End platform, 2. Spring connector, 3. First spring, 4. Limiting block, 5. First sliding sleeve, 6. Lifting platform, 7. Sliding rod, 8. Tension sensor, 9. Base, 10. Mating ring, 11. Shock-absorbing base, 12. Spherical bowl structure, 13. Electric telescopic rod, 14. Support seat, 15. Lead screw, 16. Lead screw motor, 17. Spherical hinge structure, 18. Lead screw nut, 19. Second sliding sleeve, 20. Pressure plate, 21. Electrode compression spring, 22. Limiting ring. Detailed Implementation

[0017] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0018] like Figures 1-3As shown, a multi-degree-of-freedom robot end effector platform includes a base 9. A lead screw motor 16 is disposed in the middle of the upper end of the base 9. A lead screw 15 is disposed on the output end of the lead screw motor 16. A lifting platform 6 is disposed above the base 9. A lead screw nut 18 is disposed in the middle of the lifting platform 6 and is screwed with the lead screw 15. The lifting platform 6 is driven to move up and down by the rotation of the lead screw motor 16, thereby realizing the vertical degree of freedom control of the robot end effector platform. The lead screw 15 passes through the lead screw nut 18 and is rotatably connected to the support seat 14 disposed in the upper end of the lifting platform 6. The end platform 1 is connected to the middle of the support seat 14 through a ball joint structure 17. At least two electric telescopic rods 13 are disposed between the end platform 1 and the support seat 14. One end of the electric telescopic rod 13 is connected to the end platform 1 through a flexible rubber ball joint structure, and the other end is fixed to the support seat 14. The two electric telescopic rods 13 are distributed at a 90° angle in the circumferential direction. The deflection of the end platform 1 is controlled by the extension and retraction of two electric telescopic rods 13, and the deflection can be adjusted at any angle. The flexible rubber ball joint structure can achieve rotation, extension and retraction, and compression, providing sufficient freedom for the deflection of the end platform 1.

[0019] In this embodiment, at least four first springs 3 are provided on the end platform 1. The four first springs 3 are evenly distributed in the axial direction and distributed on the outside of the support base 14. The two ends of two of the first springs 3 are connected to the end platform 1 and the base 9 through spring connectors 2. One end of the other two first springs 3 is connected to the end platform 1 through spring connectors 2, and the other end is connected to the base 9 through a tension sensor 8. The two tension sensors 8 are distributed at 90° in the circumferential direction. The first springs 3 provide stable support for the deflection of the end platform 1. At the same time, by transmitting the tension to the tension sensor 8, the deflection angle is controlled. The lifting platform 6 is provided with through holes for the first springs 3 to pass through.

[0020] In this embodiment, a plurality of slide rods 7 are arranged around the lead screw motor 16, a first sliding sleeve 5 is provided on the lifting platform 6 to slide in cooperation with the slide rods 7, a second sliding sleeve 19 is provided on the base 9 to slide in cooperation with the slide rods 7, and a limit block 4 is provided at the upper end of the slide rods 7 to prevent the lifting platform 6 from rising excessively.

[0021] The base 9 is a hollow structure. A shock-absorbing base 11 is provided at the bottom of the base 9. The slide rod 7 passes through the base 9 and is connected to the shock-absorbing base 11. A second spring is provided between the second slide sleeve 19 and the shock-absorbing base 11, and the second spring is sleeved on the slide rod 7.

[0022] In this embodiment, an electrode compression spring 21 is provided inside the base 9, and a pressure plate 20 is provided at the end of the electrode compression spring 21. A piezoelectric ceramic electrode sheet that cooperates with the pressure plate 20 is provided inside the shock-absorbing base 11, and the piezoelectric ceramic electrode sheet is located inside the limiting ring 22 provided inside the shock-absorbing base 11.

[0023] The piezoelectric ceramic electrode sheet receives vibration and load data from the compression, and the robot combines the vibration data to avoid excessive vibration and prevent overload.

[0024] The flexible rubber ball joint structure includes a universal ball joint and a spherical cup structure 12. The universal ball joint is mounted on the electric telescopic rod 13 and is movably mounted inside the spherical cup structure 12. The internal space of the spherical cup structure 12 is larger than the size of the universal ball joint. An elastic rubber pad is provided at the bottom of the spherical cup structure 12. The universal ball joint abuts against the elastic rubber pad to provide freedom during electric telescopic movement.

[0025] In this embodiment, a mating ring 10 is provided at the upper end of the shock-absorbing base 11. The outer diameter of the mating ring 10 is smaller than the outer diameter of the shock-absorbing base 11, so that a step is formed between the mating ring 10 and the shock-absorbing base 11. The mating ring 10 is inserted into the lower end of the base 9.

[0026] A control method for the aforementioned multi-degree-of-freedom robot end effector platform includes the following steps: S1: During operation, the end platform 1 is tilted in different directions by the extension and retraction of the two electric telescopic rods 13. The universal ball head of the flexural rubber ball joint structure rotates adaptively, and the elastic rubber pad layer deforms adaptively to ensure that the end platform 1 can deflect freely. S2: Two tension sensors 8 collect the tension of the first spring 3 in real time, and construct the relationship between the tension of the first spring 3 and the tilt angle of the end platform 1 in this direction. The conversion formula; ; in, For the current moment t The tension data collected by tension sensor 8 The initial state of the first spring 3 is measured by the tension data collected by the tension sensor 8. k Let be the stiffness coefficient of the first spring 3. The straight-line distance between the spherical hinge structure 17 and the first spring 3; S3: The robot plans the tilt angle of the end-effector 1 in different directions according to the execution instructions, inputs the formula into the conversion formula, and calculates the tension force output by the first spring 3 to the tension sensor 8 after the end-effector 1 moves into position. , T To determine the planned motion time, the tension sensor 8 collects tension data in real time during the motion of the end platform 1 until the tension is reached. After that, the electric telescopic pole 13 stopped extending and retracting; S4: The electrode spring 21, together with the pressure plate 20, compresses the piezoelectric ceramic electrode sheet, and collects the force in the vertical direction in real time to obtain the load data of the robot end effector platform. When the load data is greater than the set threshold, an alarm is issued to prevent the robot end effector platform from being overloaded.

[0027] This invention, serving as an end effector platform for robots, is particularly suitable for industrial robot applications. It enables the end effector platform 1 to perform only deflection and movement in the left-right, forward-backward, and vertical directions, with independent sensing and control of movement in each direction. This adapts to complex scenarios such as curved surface grinding and irregular workpiece gripping. The multi-directional force sensing unit, in conjunction with spring components and linear guide mechanisms, can buffer instantaneous force fluctuations, limit excessive posture deviations, and prevent the end effector from scratching the workpiece (in grinding scenarios) or causing it to fall off (in gripping scenarios), thus improving operational stability.

Claims

1. A multi-degree-of-freedom robot end effector platform, characterized in that, The device includes a base, a lead screw motor located at the upper center of the base, a lead screw at the output end of the lead screw motor, a lifting platform above the base, a lead screw nut in the middle of the lifting platform that engages with the lead screw, the lead screw passing through the lead screw nut and rotatably connected to a support seat at the upper end of the lifting platform, an end platform connected to the middle of the support seat via a ball joint structure, at least two electric telescopic rods between the end platform and the support seat, one end of each electric telescopic rod being connected to the end platform via a flexible rubber ball joint structure, and the other end being fixed to the support seat, with the two electric telescopic rods distributed at a 90° angle in the circumferential direction; At least four first springs are provided on the end platform. The four first springs are evenly distributed in the axial direction and are located on the outside of the support base. Two of the first springs are connected to the end platform and the base at both ends through spring connectors. One end of the other two first springs is connected to the end platform through a spring connector, and the other end is connected to the base through a tension sensor. The two tension sensors are distributed at 90° in the circumferential direction. The lifting platform has through holes for the first springs to pass through. The base is a hollow structure. A shock-absorbing base is provided at the bottom of the base. An electrode spring is provided inside the base. A pressure plate is provided at the end of the electrode spring. A piezoelectric ceramic electrode sheet that cooperates with the pressure plate is provided inside the shock-absorbing base. The piezoelectric ceramic electrode sheet is located in a limiting ring provided inside the shock-absorbing base.

2. The multi-degree-of-freedom robot end effector platform according to claim 1, characterized in that, The lead screw motor is surrounded by several sliding rods, the lifting platform is provided with a first sliding sleeve that slides with the sliding rods, and the base is provided with a second sliding sleeve that slides with the sliding rods.

3. The multi-degree-of-freedom robot end effector platform according to claim 2, characterized in that, The slide rod passes through the base and connects to the shock-absorbing base. A second spring is provided between the second slide sleeve and the shock-absorbing base, and the second spring is sleeved on the slide rod.

4. The multi-degree-of-freedom robot end effector platform according to claim 3, characterized in that, The flexible rubber ball joint structure includes a universal ball joint and a spherical cup structure. The universal ball joint is mounted on the electric telescopic rod and is movably mounted inside the spherical cup structure. The internal space of the spherical cup structure is larger than the size of the universal ball joint. An elastic rubber pad is provided at the bottom of the spherical cup structure. The universal ball joint abuts against the elastic rubber pad to provide freedom during electric telescopic movement.

5. The multi-degree-of-freedom robot end effector platform according to claim 4, characterized in that, The upper end of the damping base is provided with a mating ring. The outer diameter of the mating ring is smaller than the outer diameter of the damping base, so that a step is formed between the mating ring and the damping base. The mating ring is inserted into the lower end of the base.

6. A control method for a multi-degree-of-freedom robot end effector platform as described in claim 5, characterized in that, Includes the following steps: S1: During operation, the end platform tilts in different directions by extending and retracting two electric telescopic rods. The universal ball joint of the flexural rubber ball joint structure rotates adaptively, while the elastic rubber pad layer deforms adaptively, ensuring that the end platform can deflect freely. S2: Two tension sensors collect the tension of the first spring in real time, and construct a relationship between the tension of the first spring and the tilt angle of the end platform in that direction. The conversion formula; ； in, For the current moment t The tension data collected by the tension sensor The tension data collected by the tension sensor in the initial state of the first spring. k Let be the stiffness coefficient of the first spring. The straight-line distance between the spherical hinge structure and the first spring; S3: The robot plans the tilt angle of the end effector platform in different directions according to the execution instructions, inputs it into the conversion formula, and calculates the tension force of the first spring on the tension sensor after the end effector platform moves into position. , T To determine the planned motion time, the tension sensor collects tension data in real time during the end-effector's movement until the tension is reached. After that, the electric telescopic pole stopped extending and retracting; S4: The electrode spring, together with the pressure plate, compresses the piezoelectric ceramic electrode sheet, and collects the vertical force in real time to obtain the load data of the robot end effector platform. When the load data exceeds the set threshold, an alarm is issued to prevent the robot end effector platform from being overloaded.

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