A parallel, finely adjustable compliant joint and its working method

Abstract

This invention relates to the field of robot joint technology, specifically to a parallel, finely adjustable compliant joint and its operating method. The compliant joint includes: a cylindrical outer shell with multiple sliding grooves; an integral rotating assembly located at one end of the outer shell and connected to it, which drives the entire outer shell to rotate; a flexible output assembly located in the middle of the outer shell, comprising an output disk and lead-out components; the output disk being connected to the outer shell; and lead-out components all located on the output disk, inserted into the sliding grooves, and connected to an external load; a coarse stiffness adjustment assembly and a fine stiffness adjustment assembly located on either side of the output disk, with the fine stiffness adjustment assembly positioned closer to the integral rotating assembly. Structurally, it employs a parallel superposition stiffness adjustment principle, enabling both wide-range and fine-tuning of stiffness.

Description

Technical Field

[0001] This invention relates to the field of robot joint technology, specifically to a parallel compliant joint with finely adjustable stiffness and its working method. Background Technology

[0002] As human needs in industry, daily life, and military applications become increasingly diverse, new types of variable-configuration mechanisms adapted to complex mechanical environments have emerged, including modular self-assembly robots. Variable-configuration mechanisms often contain several kinematic pairs, which function to realize the mechanism's unfolding and locking motions and the transmission of forces. Among these, rotary joints are the most common type of kinematic pair structure. Rotary joints are the structural foundation for the motion of variable-configuration mechanisms, and their stiffness characteristics are a crucial factor affecting the static and dynamic characteristics of the mechanism. The stiffness of rotary joints has a multifaceted, nonlinear, and variable effect on system characteristics, depending on the specific scenario. For example, in multi-degree-of-freedom robotic arms, traditional rigid rotary joints can withstand high loads, have high response speeds, and ensure positional accuracy, but are prone to shocks and vibrations, adversely affecting system safety. To ensure that variable-configuration mechanisms can better adapt to the environment, it is necessary to develop variable-stiffness compliant joints that meet the requirements.

[0003] Currently, most variable stiffness compliant joint stiffness adjustment mechanisms have fixed stiffness adjustment characteristics and cannot simultaneously satisfy both fine stiffness adjustment and wide-range stiffness adjustment. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the stiffness adjustment characteristics of the existing variable stiffness compliant joint stiffness adjustment mechanism are fixed and cannot simultaneously satisfy fine stiffness adjustment and large-range stiffness adjustment, thereby providing a parallel compliant joint with finely adjustable stiffness and its working method.

[0005] To address the aforementioned technical problems, this invention provides a parallel-type compliant joint with finely adjustable stiffness, comprising: a cylindrical outer shell with multiple sliding grooves, an integral rotating assembly located at one end of the cylindrical outer shell and connected to it, the integral rotating assembly driving the cylindrical outer shell to rotate as a whole; a flexible output assembly located in the middle of the cylindrical outer shell, the flexible output assembly including an output disk and lead-out members, the output disk being connected to the cylindrical outer shell, the lead-out members being disposed on the output disk and inserted into the sliding grooves, the lead-out members being connected to an external load; a coarse stiffness adjustment assembly and a fine stiffness adjustment assembly located on both sides of the output disk, the fine stiffness adjustment assembly being disposed closer to the integral rotating assembly.

[0006] Furthermore, the overall rotating assembly includes a frameless motor, a fine-tuning motor mount, a load-bearing large bearing, a fine-tuning module fixing plate, a cylindrical shell, and stator brake components. The stator of the frameless motor is fixedly connected to the inner ring of the load-bearing large bearing through three stator brake components. The rotor of the frameless motor is fixedly connected to the fine-tuning motor mount. The fine-tuning motor mount is located on the fine-tuning module fixing plate, which is connected to the cylindrical shell. The rotor of the frameless motor drives the cylindrical shell to complete the overall rotation through the fine-tuning motor mount.

[0007] Furthermore, the flexible output component includes an output disk, a U-shaped spring, and a bearing with a constant cross-section. The U-shaped spring is connected to the output disk, the output disk is fixedly connected to the inner ring of the bearing with a constant cross-section, the outer ring of the bearing with a constant cross-section is connected to the cylindrical shell, and the lead-out member is connected to the output disk.

[0008] Furthermore, there are two U-shaped springs, which are symmetrically arranged on the output disk.

[0009] Furthermore, the stiffness coarse adjustment assembly includes a coarse adjustment motor, a coarse adjustment motor base, a coarse adjustment module fixing plate, coarse adjustment guide rails, a coarse adjustment gear, and a coarse adjustment rack with a column. The stator of the coarse adjustment motor is connected to the coarse adjustment motor base, the coarse adjustment motor base is mounted on the coarse adjustment module fixing plate, two coarse adjustment guide rails are symmetrically arranged on the coarse adjustment module fixing plate, the coarse adjustment rack with a column is connected to the two coarse adjustment guide rails via a slider, the coarse adjustment gear is fixedly connected to the rotor of the coarse adjustment motor and meshes with the coarse adjustment rack with a column, and one end of the coarse adjustment rack with a column is inserted into a U-shaped spring.

[0010] Furthermore, the stiffness fine-tuning assembly includes a fine-tuning motor, fine-tuning guide rails, fine-tuning gears, fine-tuning racks, and compression springs. The stator of the fine-tuning motor is connected to a fine-tuning motor mount, which is mounted on the fine-tuning module mounting plate. Two fine-tuning guide rails are symmetrically fixed on the fine-tuning module mounting plate. The fine-tuning rack is slidably connected to the fine-tuning guide rails via a slider. The fine-tuning gear is connected to the rotor of the fine-tuning motor and meshes with the fine-tuning rack. One end of the compression spring is fixed in the cylindrical hole of the fine-tuning rack and maintains a predetermined compression amount.

[0011] Furthermore, the output disk has two inner surfaces, and the compression spring is located between the two inner surfaces and abuts against the inner surfaces.

[0012] Furthermore, both the coarse and fine adjustment racks with columns include two interlocking toothed plates, which are connected to the slider.

[0013] Furthermore, the coarse adjustment guide rail and the fine adjustment guide rail are set in directions perpendicular to each other.

[0014] The present invention also provides a method for operating a compliant joint with finely adjustable stiffness in parallel configuration, comprising:

[0015] When the stiffness of the robot's rotary joint does not need to be changed but the joint angle needs to be changed, the overall rotating assembly drives the cylindrical shell to rotate, which in turn drives the output disk and the lead-out component to rotate. The lead-out component is connected to an external load to output power.

[0016] When the stiffness of the robot's rotary joint needs to be increased, a coarse stiffness adjustment is first performed using the coarse stiffness adjustment component to complete the coarse stiffness increase adjustment process. After the coarse adjustment is completed, a fine adjustment is performed using the fine stiffness adjustment component to complete the fine stiffness increase adjustment process.

[0017] The technical solution of this invention has the following advantages:

[0018] The present invention provides a parallel-type compliant joint with finely adjustable stiffness, comprising: a cylindrical outer shell, wherein the cylindrical outer shell is provided with multiple sliding grooves, and an integral rotating assembly is provided inside the cylindrical outer shell, the integral rotating assembly being located at one end of the cylindrical outer shell and connected to the cylindrical outer shell, the integral rotating assembly being used to drive the cylindrical outer shell to rotate as a whole; a flexible output assembly, disposed in the middle of the cylindrical outer shell, the flexible output assembly including an output disk and lead-out members, the output disk being connected to the cylindrical outer shell, the lead-out members being disposed on the output disk, the lead-out members being inserted into the sliding grooves, and the lead-out members being connected to an external load; a stiffness coarse adjustment assembly and a stiffness fine adjustment assembly, disposed on both sides of the output disk, the stiffness fine adjustment assembly being disposed on the side closer to the integral rotating assembly.

[0019] By installing an integral rotating assembly inside a cylindrical shell, and connecting this integral rotating assembly to the cylindrical shell, the integral rotating assembly can be rotated by the cylindrical shell. Simultaneously, a coarse stiffness adjustment assembly, a fine stiffness adjustment assembly, and a flexible output assembly are installed inside the cylindrical shell. Since the flexible output assembly includes an output disk and a lead-out component, and the lead-out component is connected to an external load, when a large range of stiffness adjustment is required, the coarse stiffness adjustment assembly is used to rotate the output disk, which in turn rotates the lead-out component within a sliding groove, thus allowing for a large range of stiffness adjustment of the external load. After the large range of stiffness adjustment is completed, fine stiffness adjustment is required. The fine stiffness adjustment assembly is used to rotate the output disk, which in turn rotates the lead-out component within a sliding groove, thus allowing for a fine adjustment of the stiffness of the external load.

[0020] This parallel, finely adjustable compliant joint utilizes a parallel, superimposed stiffness adjustment principle, enabling both wide-range and precise stiffness adjustment. Furthermore, its compact component layout results in a small overall size and minimal installation space, making it suitable for various robot rotary joint applications.

[0021] This parallel, finely adjustable compliant joint employs a gear-rack configuration in its structural design to ensure symmetrical stress distribution within the flexible output components when subjected to external loads. For stiffness adjustment, a wide range of stiffness adjustment is achieved by utilizing the non-linear deformation of a fixed U-shaped spring with varying pressure application point; while a fine-tuned stiffness adjustment is achieved by utilizing the linear variation of output torque with application point position when compression remains constant.

[0022] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the parallel-type compliant joint with finely adjustable stiffness provided by the present invention;

[0025] Figure 2 A cross-sectional view of the parallel, finely adjustable, compliant joint provided by the present invention.

[0026] Figure 3 An exploded view of the parallel, finely adjustable, compliant joint provided by the present invention.

[0027] Figure 4 An exploded view of the parallel-type compliant joint with finely adjustable stiffness provided by the present invention.

[0028] Figure 5 A schematic diagram of the coarse adjustment guide rail of the parallel compliant joint with finely adjustable stiffness provided by the present invention.

[0029] Figure 6 This is a schematic diagram of the fine-tuning guide rail for a parallel, finely adjustable stiffness compliant joint provided by the present invention.

[0030] Figure 7 A schematic diagram of the output disk of the parallel-connected, finely adjustable stiffness compliant joint provided by the present invention;

[0031] Figure 8 A schematic diagram of the structure of the lead-out component of the parallel-type compliant joint with finely adjustable stiffness provided by the present invention;

[0032] Figure 9 A schematic diagram of the stiffness fine-tuning component of the parallel-type compliant joint with finely adjustable stiffness provided by the present invention.

[0033] Figure 10 A schematic diagram of the structure of the stiffness fine-tuning component of the parallel-type compliant joint with finely adjustable stiffness provided by the present invention after operation.

[0034] Figure 11 A schematic diagram of the stiffness coarse adjustment component of the parallel compliant joint with finely adjustable stiffness provided by the present invention.

[0035] Figure 12 A schematic diagram of the structure of the stiffness coarse adjustment component of the parallel compliant joint with finely adjustable stiffness provided by the present invention after operation.

[0036] Figure 13 A schematic diagram of the parallel-type compliant joint with finely adjustable stiffness and a column coarse-adjustment rack provided by the present invention.

[0037] Figure 14 This is a schematic diagram of the fine-tuning rack of the parallel, compliant joint with finely adjustable stiffness provided by the present invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1-1. Frameless motor; 1-2. Fine-tuning motor base; 1-3. Load-bearing large bearing; 1-4. Fine-tuning module fixing plate; 1-5. Cylindrical outer shell; 1-6. Stator brake component; 2-1. Output disc; 2-2. U-shaped spring; 2-3. Lead-out component; 2-4. Uniform cross-section bearing; 3-1. Coarse-tuning motor; 3-2. Coarse-tuning motor base; 3-3. Coarse-tuning module fixing plate; 3-4. Coarse-tuning guide rail; 3-5. Coarse-tuning gear; 3-6. Coarse-tuning rack with column; 4-1. Fine-tuning motor; 4-2. Fine-tuning guide rail; 4-3. Fine-tuning gear; 4-4. Fine-tuning rack; 4-5. Compression spring; 5. Slider; 6. Sliding groove; A. Inner facade. Detailed Implementation

[0040] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.

[0041] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or connections that allow for communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0043] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this disclosure. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this disclosure, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0045] The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0046] Please see Figures 1 to 14 As shown, the present invention provides a parallel compliant joint with finely adjustable stiffness, comprising: a cylindrical shell 1-5, wherein the cylindrical shell 1-5 is provided with a plurality of sliding grooves 6, and an integral rotating assembly is provided inside the cylindrical shell 1-5, the integral rotating assembly being located at one end of the cylindrical shell 1-5 and connected to the cylindrical shell 1-5, the integral rotating assembly being used to drive the cylindrical shell 1-5 to rotate as a whole; a flexible output assembly, disposed in the middle of the cylindrical shell 1-5, the flexible output assembly including an output disk 2-1 and lead-out members 2-3, the output disk 2-1 being connected to the cylindrical shell 1-5, the lead-out members 2-3 being disposed on the output disk 2-1, the lead-out members 2-3 being inserted into the sliding grooves 6, and the lead-out members 2-3 being connected to an external load (not shown in the figure); a stiffness coarse adjustment assembly and a stiffness fine adjustment assembly, disposed on both sides of the output disk 2-1, the stiffness fine adjustment assembly being disposed on the side closer to the integral rotating assembly.

[0047] By installing an integral rotating assembly inside the cylindrical shell 1-5 and connecting it to the cylindrical shell 1-5, the integral rotating assembly can be rotated by the cylindrical shell 1-5. Simultaneously, a coarse stiffness adjustment assembly, a fine stiffness adjustment assembly, and a flexible output assembly are installed inside the cylindrical shell 1-5. Since the flexible output assembly includes an output disk 2-1 and a lead-out member 2-3, and the lead-out member 2-3 is connected to an external load, when a large range of stiffness adjustment is required, the coarse stiffness adjustment assembly rotates the output disk 2-1, which in turn rotates the lead-out member 2-3 within the sliding groove 6, thus allowing for a large range of stiffness adjustment of the external load. After the large range of stiffness adjustment is completed, fine stiffness adjustment is required. The fine stiffness adjustment assembly rotates the output disk 2-1, which in turn rotates the lead-out member 2-3 within the sliding groove 6, thus allowing for a fine adjustment of the stiffness of the external load.

[0048] This parallel, finely adjustable compliant joint utilizes a parallel, superimposed stiffness adjustment principle, enabling both wide-range and precise stiffness adjustment. Furthermore, its compact component layout results in a small overall size and minimal installation space, making it suitable for various robot rotary joint applications.

[0049] In some optional embodiments, the overall rotating assembly includes a frameless motor 1-1, a fine-tuning motor mount 1-2, a load-bearing bearing 1-3, a fine-tuning module mounting plate 1-4, a cylindrical shell 1-5, and stator brake components 1-6. The stator of the frameless motor 1-1 is fixedly connected to the inner ring of the load-bearing bearing 1-3 through three stator brake components 1-6. The rotor of the frameless motor 1-1 is fixedly connected to the fine-tuning motor mount 1-2. The fine-tuning motor mount 1-2 is mounted on the fine-tuning module mounting plate 1-4. The fine-tuning module mounting plate 1-4 is connected to the cylindrical shell 1-5. The rotor of the frameless motor 1-1 drives the cylindrical shell 1-5 to complete the overall rotation through the fine-tuning motor mount 1-2, thereby realizing the overall rotation of a parallel, finely adjustable, compliant joint.

[0050] Three stator brake components 1-6 are installed on the outer wall of the frameless motor 1-1, and the three stator brake components 1-6 are spaced apart. The three stator brake components 1-6 are connected to the load-bearing large bearing 1-3, thereby realizing the connection between the frameless motor 1-1 and the load-bearing large bearing 1-3.

[0051] Specifically, the flexible output assembly includes an output disk 2-1, a U-shaped spring 2-2, and a constant cross-section bearing 2-4. The U-shaped spring 2-2 is connected to the output disk 2-1, the output disk 2-1 is fixedly connected to the inner ring of the constant cross-section bearing 2-4, the outer ring of the constant cross-section bearing 2-4 is connected to the cylindrical outer shell 1-5, and the lead-out member 2-3 is connected to the output disk 2-1.

[0052] A constant cross-section bearing 2-4 is fitted onto the output disk 2-1. This constant cross-section bearing 2-4 is adapted to fit with the cylindrical outer shell 1-5, allowing the output disk 2-1 to rotate inside the cylindrical outer shell 1-5. Simultaneously, two U-shaped springs 2-2 are symmetrically arranged on the output disk 2-1. These U-shaped springs 2-2 are adapted to connect to a stiffness coarse adjustment component. The movement of the stiffness coarse adjustment component relative to the U-shaped springs 2-2 causes the output disk 2-1 to rotate, thereby driving the lead-out piece 2-3 mounted on the output disk 2-1 to rotate, thus achieving a wide range of stiffness adjustment for external loads.

[0053] In some optional embodiments, the stiffness coarse adjustment assembly includes a coarse adjustment motor 3-1, a coarse adjustment motor base 3-2, a coarse adjustment module fixing plate 3-3, coarse adjustment guide rails 3-4, a coarse adjustment gear 3-5, and a coarse adjustment rack with a column 3-6. The stator of the coarse adjustment motor 3-1 is connected to the coarse adjustment motor base 3-2, the coarse adjustment motor base 3-2 is mounted on the coarse adjustment module fixing plate 3-3, the two coarse adjustment guide rails 3-4 are symmetrically mounted on the coarse adjustment module fixing plate 3-3, the coarse adjustment rack with a column 3-6 is connected to the two coarse adjustment guide rails 3-4 via a slider 5, the coarse adjustment gear 3-5 is fixedly connected to the rotor of the coarse adjustment motor 3-1 and meshes with the coarse adjustment rack with a column 3-6, and one end of the coarse adjustment rack with a column 3-6 is inserted into a U-shaped spring 2-2.

[0054] The coarse adjustment motor 3-1, coarse adjustment motor base 3-2, and coarse adjustment module fixing plate 3-3 are arranged. The coarse adjustment module fixing plate 3-3 is located at the end of the cylindrical outer shell 1-5 away from the frameless motor 1-1, and the coarse adjustment motor base 3-2 is provided on the coarse adjustment module fixing plate 3-3. The coarse adjustment motor 3-1 is located inside the coarse adjustment motor base 3-2, that is, the coarse adjustment motor base 3-2 provides an installation position for the coarse adjustment motor 3-1. Furthermore, the coarse adjustment motor 3-1 is connected to the coarse adjustment gear 3-5, which is located inside the cylindrical outer shell 1-5 and is adapted to the coarse adjustment rack 3-6 with a column. One end of the coarse adjustment rack 3-6 with a column is inserted into the U-shaped spring 2- Within section 2, since the bottom of the coarse adjustment rack 3-6 with column is equipped with a slider 5, the coarse adjustment motor 3-1 can rotate, driving the coarse adjustment gear 3-5 to rotate, which in turn drives the coarse adjustment rack 3-6 with column and the slider 5 to move on the coarse adjustment guide rail 3-4. That is, the coarse adjustment rack 3-6 with column translates along the coarse adjustment guide rail 3-4 between the U-shaped springs 2-2, so that the contact point between the column of the coarse adjustment rack 3-6 and the U-shaped spring 2-2 is appropriately close to the end fulcrum of the U-shaped spring 2-2, so that the deformation of the U-shaped spring 2-2 is smaller under the same external load torque, and finally the coarse adjustment process of increasing stiffness is completed. The coarse adjustment motor 3-1 rotates in the opposite direction to complete the coarse adjustment process of decreasing stiffness.

[0055] This parallel, finely adjustable compliant joint employs a gear meshing with a rack in its structural design, ensuring symmetrical stress distribution among the flexible output components within the joint when subjected to external loads. For stiffness adjustment, a wide range of stiffness adjustment is achieved by utilizing the non-linear deformation of the single-sided fixed U-shaped spring 2-2 with the position of the pressure application point; while a fine-range stiffness adjustment is achieved by utilizing the linear change in output torque of the compression spring 4-5 with the position of the application point when the compression is constant.

[0056] The coarse adjustment guide rail 3-4 is mounted on the coarse adjustment module fixing plate 3-3, and there are two coarse adjustment guide rails 3-4 arranged symmetrically; there are four sliders 5, and two sliders 5 are mounted on the coarse adjustment guide rail 3-4 as a group, and the sliders 5 are connected to the coarse adjustment rack 3-6 with column.

[0057] Specifically, the stiffness fine-tuning assembly includes a fine-tuning motor 4-1, a fine-tuning guide rail 4-2, a fine-tuning gear 4-3, a fine-tuning rack 4-4, and a compression spring 4-5. The stator of the fine-tuning motor 4-1 is connected to the fine-tuning motor base 1-2, which is mounted on the fine-tuning module mounting plate 1-4. The two fine-tuning guide rails 4-2 are symmetrically fixed on the fine-tuning module mounting plate 1-4. The fine-tuning rack 4-4 is slidably connected to the fine-tuning guide rail 4-2 via a slider 5. The fine-tuning gear 4-3 is connected to the rotor of the fine-tuning motor 4-1 and meshes with the fine-tuning rack 4-4. One end of the compression spring 4-5 is fixed in the cylindrical hole of the fine-tuning rack 4-4 and maintains a predetermined compression amount.

[0058] The fine-tuning motor 4-1, the fine-tuning motor mount 1-2, and the fine-tuning module mounting plate 1-4 are arranged such that the fine-tuning module mounting plate 1-4 is located inside the cylindrical outer shell 1-5, near one end of the frameless motor 1-1. The fine-tuning motor mount 1-2 is mounted on the fine-tuning module mounting plate 1-4, and the fine-tuning motor 4-1 is located inside the fine-tuning motor mount 1-2, meaning the fine-tuning motor mount 1-2 provides an installation position for the fine-tuning motor 4-1. Furthermore, the fine-tuning motor 4-1 is connected to the fine-tuning gear 4-3, which is located inside the cylindrical outer shell 1-5 and is adapted to the fine-tuning rack 4-4 with a column. The compression spring 4... -5 is fixed at one end in the cylindrical hole of the fine-adjusting rack 4-4, maintaining a predetermined compression. Since the bottom of the fine-adjusting rack 4-4 has a slider 5, it can be rotated by the fine-adjusting motor 4-1. The rotor of the fine-adjusting motor 4-1 drives the fine-adjusting gear 4-3, which is fixedly connected to it, to rotate. The rotation of the fine-adjusting gear 4-3 causes the fine-adjusting rack 4-4 to translate along the fine-adjusting guide rail 4-2 between the two inner surfaces A of the output disk 2-1. This makes the point of action of the compression spring 4-5 and the two inner surfaces A of the output disk 2-1 appropriately closer to the outer ring. By increasing the resistance arm, the deformation of the compression spring 4-5 under the same external load torque is reduced, ultimately completing the fine adjustment process of increasing stiffness. Rotating the fine-adjusting motor 4-1 in the opposite direction completes the fine adjustment process of decreasing stiffness.

[0059] The output disk 2-1 has two inner surfaces A, and the compression spring 4-5 is located between the two inner surfaces A and abuts against the inner surfaces A.

[0060] Two inner surfaces A are located in the middle of the output disk 2-1, and U-shaped springs 2-2 are located on both sides of the two inner surfaces A. That is, one end of the U-shaped spring 2-2 abuts against the inner surface A, and the other end abuts against the interior of the output disk 2-1.

[0061] In this embodiment, the coarse adjustment rack 3-6 and fine adjustment rack 4-4 with columns each include two interlocking toothed pieces, which are connected to the slider 5.

[0062] The coarse adjustment rack 3-6 and fine adjustment rack 4-4 with column are composed of two separate, interlocking toothed pieces. Two sliders 5 are provided at the bottom of one toothed piece, that is, four sliders 5 are provided at the bottom of the two toothed pieces. The four sliders 5 are slidably set on the coarse adjustment guide rail 3-4 and the fine adjustment guide rail 4-2, thereby realizing the sliding of the coarse adjustment rack 3-6 and fine adjustment rack 4-4 with column.

[0063] Specifically, the coarse adjustment guide rail 3-4 and the fine adjustment guide rail 4-2 are set in directions perpendicular to each other.

[0064] The present invention also provides a working method for a compliant joint with finely adjustable stiffness in parallel, comprising: when the stiffness of the robot rotary joint does not need to be changed but the joint angle needs to be changed, the cylindrical shell 1-5 is rotated by the overall rotating assembly, and the output disk 2-1 and the lead-out part 2-3 are rotated, and the lead-out part 2-3 is connected to an external load for power output.

[0065] When the stiffness of the robot's rotary joint needs to be increased, a coarse stiffness adjustment is first performed using the coarse stiffness adjustment component to complete the coarse stiffness increase adjustment process. After the coarse adjustment is completed, a fine adjustment is performed using the fine stiffness adjustment component to complete the fine stiffness increase adjustment process.

[0066] Specifically, when the stiffness of the robot's rotary joint does not need to be changed but the joint angle needs to be changed, the frameless motor 1-1 provides power. The inner rotor of the frameless motor 1-1 drives the fine-tuning motor base 1-2 to rotate. Since the fine-tuning motor base 1-2 is fixed on the fine-tuning module fixing plate 1-4, it drives the fine-tuning module fixing plate 1-4 and the fine-tuning guide rail 4-2 fixed on it to rotate. This drives the fine-tuning rack 4-4, which is engaged with the fine-tuning guide rail 4-2 through the slider 5, to rotate. Finally, it drives the compression spring 4-5 fixed in the cylindrical hole of the fine-tuning rack 4-4 to push the output disk 2-1 to rotate. The four cylinders of the lead-out part 2-3, which is fixedly connected to the output disk 2-1, connect to the external load for power output.

[0067] When the stiffness of the robot's rotary joint needs to be increased, a coarse adjustment of stiffness is first performed. The external load torque acts on the output disk 2-1, which is fixedly connected to it, through the lead-out component 2-3. The output disk 2-1 then transmits the external load torque to the U-shaped spring 2-2 and the compression spring 4-5. The stiffness is coarsely adjusted by changing the deformation of the U-shaped spring 2-2 under the same load torque. The coarse adjustment motor 3-1 provides power, and the rotor of the coarse adjustment motor 3-1 drives the coarse adjustment gear 3-5, which is fixedly connected to it, to rotate. The rotation of the coarse adjustment gear 3-5 causes the coarse adjustment rack 3-6 with a column to translate along the coarse adjustment guide rail 3-4 between the U-shaped springs 2-2. This makes the contact point between the column of the coarse adjustment rack 3-6 and the U-shaped spring 2-2 appropriately closer to the end fulcrum of the U-shaped spring 2-2, so that the deformation of the U-shaped spring 2-2 under the same external load torque is smaller, and finally the coarse adjustment process of increasing stiffness is completed.

[0068] After coarse adjustment, fine adjustment is performed. The external load torque acts on the output disk 2-1, which is fixedly connected to it, through the lead-out part 2-3. The output disk 2-1 then transmits the external load torque to the U-shaped spring 2-2 and the compression spring 4-5. The stiffness is finely adjusted by changing the deformation of the compression spring 4-5 under the same load torque. Power is provided by the fine adjustment motor 4-1. The rotor of the fine adjustment motor 4-1 drives the fine adjustment gear 4-3, which is fixedly connected to it, to rotate. The rotation of the fine adjustment gear 4-3 causes the fine adjustment rack 4-4 to translate along the fine adjustment guide rail 4-2 between the two inner surfaces A of the output disk 2-1. This makes the point of action of the compression spring 4-5 and the two inner surfaces A of the output disk 2-1 appropriately closer to the outer ring. By increasing the resistance arm, the deformation of the compression spring 4-5 under the same external load torque is reduced, and finally the fine adjustment process of stiffness increase adjustment is completed.

[0069] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A parallel, finely adjustable, compliant joint, characterized in that, include: A cylindrical shell (1-5) is provided with multiple sliding grooves (6). An integral rotating assembly is provided inside the cylindrical shell (1-5). The integral rotating assembly is located at one end of the cylindrical shell (1-5) and connected to the cylindrical shell (1-5). The integral rotating assembly is used to drive the cylindrical shell (1-5) to rotate as a whole. A flexible output assembly is located in the middle of the cylindrical shell (1-5). The flexible output assembly includes an output disk (2-1) and lead-out parts (2-3). The output disk (2-1) is connected to the cylindrical shell (1-5). The lead-out parts (2-3) are all located on the output disk (2-1). The lead-out parts (2-3) are inserted into the sliding groove (6) and connected to the external load. The coarse stiffness adjustment component and the fine stiffness adjustment component are located on both sides of the output disk (2-1), with the fine stiffness adjustment component located closer to the side of the overall rotating component. The flexible output assembly includes an output disk (2-1), a U-shaped spring (2-2), and a bearing with a constant cross-section (2-4). The U-shaped spring (2-2) is connected to the output disk (2-1), the output disk (2-1) is fixedly connected to the inner ring of the bearing with a constant cross-section (2-4), the outer ring of the bearing with a constant cross-section (2-4) is connected to the cylindrical shell (1-5), and the lead-out part (2-3) is connected to the output disk (2-1). The stiffness coarse adjustment assembly includes a coarse adjustment motor (3-1), a coarse adjustment gear (3-5), and a coarse adjustment rack with a column (3-6); the coarse adjustment gear (3-5) is fixedly connected to the rotor of the coarse adjustment motor (3-1) and meshes with the coarse adjustment rack with a column (3-6); one end of the coarse adjustment rack with a column (3-6) is inserted into the U-shaped spring (2-2); The stiffness fine-tuning assembly includes a fine-tuning motor (4-1), a fine-tuning gear (4-3), a fine-tuning rack (4-4), and a compression spring (4-5). The fine-tuning gear (4-3) is connected to the rotor of the fine-tuning motor (4-1) and meshes with the fine-tuning rack (4-4). One end of the compression spring (4-5) is fixed in the cylindrical hole of the fine-tuning rack (4-4) and maintains a predetermined compression amount. The output disk (2-1) has two inner surfaces (A), and the compression spring (4-5) is located between the two inner surfaces (A) and abuts against the inner surfaces (A).

2. The parallel-type compliant joint with finely adjustable stiffness according to claim 1, characterized in that, The overall rotating assembly includes a frameless motor (1-1), a fine-tuning motor mount (1-2), a load-bearing large bearing (1-3), a fine-tuning module mounting plate (1-4), a cylindrical shell (1-5), and a stator brake assembly (1-6). The stator of the frameless motor (1-1) is fixedly connected to the inner ring of the load-bearing large bearing (1-3) through three stator brake assemblies (1-6). The rotor of the frameless motor (1-1) is fixedly connected to the fine-tuning motor mount (1-2). The fine-tuning motor mount (1-2) is located on the fine-tuning module mounting plate (1-4). The fine-tuning module mounting plate (1-4) is connected to the cylindrical shell (1-5). The rotor of the frameless motor (1-1) drives the cylindrical shell (1-5) to complete the overall rotation through the fine-tuning motor mount (1-2).

3. A parallel-type compliant joint with finely adjustable stiffness according to claim 2, characterized in that, There are two U-shaped springs (2-2), which are symmetrically arranged on the output disk (2-1).

4. A parallel-type compliant joint with finely adjustable stiffness according to claim 2 or 3, characterized in that, The stiffness coarse adjustment assembly includes a coarse adjustment motor base (3-2), a coarse adjustment module fixing plate (3-3), and a coarse adjustment guide rail (3-4). The stator of the coarse adjustment motor (3-1) is connected to the coarse adjustment motor base (3-2), the coarse adjustment motor base (3-2) is set on the coarse adjustment module fixing plate (3-3), and two coarse adjustment guide rails (3-4) are symmetrically set on the coarse adjustment module fixing plate (3-3). The coarse adjustment rack (3-6) with column is connected to the two coarse adjustment guide rails (3-4) through a slider (5).

5. A parallel-type compliant joint with finely adjustable stiffness according to claim 4, characterized in that, The stiffness fine-tuning assembly includes fine-tuning guide rails (4-2), the stator of the fine-tuning motor (4-1) is connected to the fine-tuning motor base (1-2), the fine-tuning motor base (1-2) is set on the fine-tuning module fixing plate (1-4), two fine-tuning guide rails (4-2) are symmetrically fixed on the fine-tuning module fixing plate (1-4), and the fine-tuning rack (4-4) is slidably connected to the fine-tuning guide rails (4-2) through the slider (5).

6. A parallel-type compliant joint with finely adjustable stiffness according to claim 5, characterized in that, The coarse adjustment rack (3-6) and fine adjustment rack (4-4) with column each include two interlocking toothed pieces, which are connected to the slider (5).

7. A parallel-type compliant joint with finely adjustable stiffness according to claim 6, characterized in that, The coarse adjustment guide rail (3-4) and the fine adjustment guide rail (4-2) are set in perpendicular directions to each other.

8. A method for operating a compliant joint with finely adjustable stiffness in parallel configuration as described in any one of claims 1-7, characterized in that, include: When the stiffness of the robot's rotary joint does not need to be changed but the joint angle needs to be changed, the cylindrical shell (1-5) is rotated by the overall rotating assembly, which in turn drives the output disk (2-1) and the lead-out part (2-3) to rotate. The lead-out part (2-3) is connected to an external load for power output. When the stiffness of the robot's rotary joint needs to be increased, a coarse stiffness adjustment is first performed using the coarse stiffness adjustment component to complete the coarse stiffness increase adjustment process. After the coarse adjustment is completed, a fine adjustment is performed using the fine stiffness adjustment component to complete the fine stiffness increase adjustment process.

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