Differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions and robot

Abstract

The invention discloses a differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions and a robot, and belongs to the technical field of robots. The device comprises a driving unit, a driving bevel gear with an elastic structure, a deformation sensing device, an output bevel gear and other connecting pieces. The driving unit consists of a permanent magnet synchronous motor and a speed reducer; the driving bevel gear is composed of a hub, a rim and an elastic spoke. The two driving units are located between the driving bevel gears, and the compact layout is achieved. When the joint transmits torque, the elastic spoke generates elastic deformation, on one hand, passive flexibility is provided for the joint, and on the other hand, the deformation can be detected through the sensing device to achieve torque sensing. The elastic and transmission functions are integrated into the gear component with the original single function, the layout of the driving unit is optimized, and the problems that in the prior art, the joint structure is complex, flexibility and compactness are difficult to consider, and torque sensing is difficult to integrate are solved.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology, specifically relating to a differential two-degree-of-freedom joint and robot that integrates passive compliance and torque sensing functions. Background Technology

[0002] As the core component enabling robot motion, the structure and performance of robot joints directly determine the robot's load capacity, accuracy, and human-robot interaction safety. Most existing robot joints are rigid, single-degree-of-freedom structures, which are insufficient to meet increasingly complex application requirements. Differential mechanisms, due to their ability to achieve two-degree-of-freedom output with a compact structure and increased load capacity, show great application potential in the field of robot joints.

[0003] The differential joint design in the current technology still has many shortcomings.

[0004] The application number CN201720210451.7 describes a motor-mounted dual-drive differential two-degree-of-freedom modular joint, in which the drive unit is located on one side of the differential module and drives the differential unit through a long transmission chain. The whole is a rigid transmission, lacking the compliance necessary for interaction with the environment, and does not integrate torque sensing function.

[0005] The two-degree-of-freedom rotational flexible differential drive joint module with application number CN201610638764.2 relies on independent, additional elastic units to achieve compliance, which further reduces the compactness of the structure and may affect dynamic performance. Moreover, its drive unit is external, which means that the motor needs to drive the differential unit through a lengthy transmission chain, resulting in a complex overall structure, large size, and difficult assembly.

[0006] The aforementioned joint structure has the following shortcomings: First, it is complex and has low integration. The external or separate layout of the drive unit results in a long transmission chain, numerous parts, and significant size and weight, which is detrimental to lightweight robot design. Second, compliance and compactness are difficult to balance. The transmission uses a rigid mechanism, lacking compliance. Compliance relies on an external, independent elastic module, which sacrifices the compactness of the joint. Third, torque sensing functionality is lacking or difficult to integrate. Existing compact rigid structures do not reserve space for torque sensors; while flexible structures with independent elastic modules also struggle to integrate high-precision torque sensors in a unified manner. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a differential two-degree-of-freedom joint and robot that integrates passive compliance and torque sensing functions. It aims to solve the technical problems of complex robot joint structure, lack of compliance safety, and difficulty in integrating torque sensing in the prior art.

[0008] To achieve the above objectives, the present invention employs the following technical solution: A differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions includes: Chassis; Two drive units are arranged back-to-back in a mirror image along the same axis and are fixedly mounted on the chassis; Two drive bevel gears are connected to the output ends of two drive units, respectively; An output bevel gear is rotatably connected to the chassis via a connector and simultaneously meshes with two drive bevel gears. The axis of the output bevel gear is perpendicular to the axis of the drive bevel gears, and the output bevel gear is used to connect the load. The two drive units are located on the axis between the two drive bevel gears; Each of the drive bevel gears includes a hub and a rim arranged circumferentially around the hub, with an elastic structure provided between the rim and the center of the hub; a deformation sensing device is provided on the elastic structure.

[0009] A further improvement of the present invention is that: Preferably, each of the drive units includes a permanent magnet synchronous motor and a reducer. The rotor of the permanent magnet synchronous motor is connected to the input of the reducer through a motor rotor connector, and the output of the reducer is connected to the corresponding drive bevel gear.

[0010] Preferably, the rotor of the permanent magnet synchronous motor is connected to the reducer via a motor rotor connector; the stator of the permanent magnet synchronous motor is connected to the motor bearing via a motor stator connector.

[0011] Preferably, a reducer bracket is fixedly mounted on the chassis, and the motor rotor connector and the reducer are respectively mounted on both sides of the reducer bracket.

[0012] Preferably, the connector includes a vertical bearing bracket fixedly mounted on the chassis, a vertical bearing fixedly mounted on the vertical bearing bracket, and the vertical bearing being fitted inside the vertical support; the outer end of the vertical support is connected to a horizontal bearing bracket for mounting the output bevel gear.

[0013] Preferably, the horizontal bearing bracket is fitted inside the horizontal bearing, and the horizontal bearing is fitted in the horizontal support; the output bevel gear is fixedly connected to the horizontal support, and the output bevel gear is provided with a bearing cover plate that limits the movement of the horizontal bearing.

[0014] Preferably, the elastic structure includes a plurality of elastic spokes distributed circumferentially along the hub; the elastic spokes are straight or curved.

[0015] Preferably, the hub, rim, and elastic structure are integrally formed.

[0016] Preferably, the elastic structure is connected to the center of the rim and hub by adhesive bonding or heat fitting.

[0017] A robot comprising a differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions as described in any of the preceding claims.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions. By adopting a coaxial back-to-back built-in layout for the first and second drive units and directly connecting them to the drive bevel gears, the lengthy external transmission chains (such as timing belts or gears) of existing technologies are completely eliminated. This design greatly reduces the number of parts, shortens the power transmission path, and makes the overall joint structure more compact and lighter. Compared with external or separate drive unit layouts, this invention achieves higher power density in the same volume and simplifies assembly and maintenance.

[0019] Furthermore, this invention designs the drive bevel gear itself as an elastic element. Specifically, by machining elastic spokes between its hub and rim, the originally rigid transmission gear acquires torsional elasticity. This design integrates the elastic function within the transmission component, avoiding the problem in existing technologies where an additional independent elastic module must be connected in series to achieve compliance. Thus, without adding extra parts or increasing joint size, it provides the joint with the ability to absorb shock and ensure human-machine interaction safety. Moreover, this invention fully utilizes the physical property of the designed elastic spokes undergoing elastic deformation when transmitting torque. By attaching strain gauges to its surface to measure this deformation, the transmitted torque can be calculated. This solution combines torque sensing functionality with the elastic spokes as an elastic element, eliminating the need for a separate torque sensor for the joint. This not only solves the technical problem of insufficient space to install torque sensors in existing solutions but also provides a low-cost, highly integrated torque measurement solution, providing hardware support for advanced force control algorithms.

[0020] Furthermore, due to the aforementioned advantages of the joints, robots composed of these joints will possess superior kinematic and dynamic performance, as well as enhanced interaction safety. Specifically, the coupled drive method allows the power of the two motors to be combined through a differential mechanism, thereby achieving double the torque output during single-degree-of-freedom motion, significantly improving the robot's explosive force and load-bearing capacity. Simultaneously, thanks to the high integration design of this invention, the robotic arm composed of multiple joints connected in series will significantly reduce its rotational inertia, effectively improving end-effector response speed and motion accuracy, providing an ideal hardware foundation for achieving highly dynamic and flexible operations. Benefiting from the passive compliance characteristics and precise torque sensing capabilities integrated within the joints, when the robot accidentally collides with the environment or personnel, it can instantly absorb impact energy using elastic elements and rapidly adjust its control strategy through torque feedback to achieve additional active compliance, thereby maximizing personnel safety. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the detailed embodiments to explain the invention and do not constitute a limitation thereof.

[0022] Figure 1 A schematic diagram of a differential two-degree-of-freedom joint that integrates passive compliance and torque sensing functions; Figure 2 A schematic diagram of a differential two-degree-of-freedom joint that integrates passive compliance and torque sensing functions; Figure 3 This is a structural schematic diagram of the connector; Figure 4 A schematic diagram of one embodiment of driving a bevel gear and a deformation sensing device; Figure 5 A schematic diagram of one embodiment of driving a bevel gear; Figure 6 A schematic diagram of one embodiment of driving a bevel gear; Wherein: 0010, chassis; 0100, drive unit; 0101, first drive unit; 0102, second drive unit; 0110, permanent magnet synchronous motor; 0111, motor rotor connector; 0112, motor stator connector; 0113, motor bearing; 0120, reducer; 0200, drive bevel gear; 0201, first drive bevel gear; 0202, second drive bevel gear; 0210, hub; 0220, rim; 0230, elastic spoke; 0300, deformation sensing device; 0400, output bevel gear; 0501, vertical bearing bracket; 0502, vertical bearing; 0503, vertical support; 0504, horizontal bearing bracket; 0505, horizontal bearing; 0506, horizontal support; 0507, bearing cover plate; 0508, reducer bracket. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings: Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] The following is a further explanation with reference to the accompanying drawings.

[0025] like Figure 1 , Figure 2 As shown, an embodiment of a differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions according to the present invention includes a frame, a drive unit 0100, a drive bevel gear 0200, a deformation sensing device 0300, an output bevel gear 0400, and connecting parts.

[0026] The frame serves as the mounting base for the entire joint and is used to support various functional components, including the chassis 0010, vertical bearing bracket 0501, vertical support 0503, horizontal bearing bracket 0504, horizontal support 0506, bearing cover plate 0507, and reducer bracket 0508.

[0027] The vertical bearing bracket 0501 is divided into two parts, left and right, which are fixed together by screws. There is a space in the middle for clamping and fixing the vertical bearing 0502. The whole is directly fixed to the middle position of the chassis 0010 by screws. The vertical bearing bracket 0501 is connected to the vertical support 0503 through the vertical bearing 0502. The vertical bearing bracket 0501 is fitted on the outside of the vertical bearing 0502, so that the vertical support 0503 can rotate freely around the axis of the vertical bearing 0502. At the same time, the vertical bearing bracket 0501 is fixedly connected to the motor stator connector 0112 by set screws to fix the position of the permanent magnet synchronous motor 0110.

[0028] The horizontal bearing bracket 0504 is divided into two parts, upper and lower, which are fixed together by screws. The horizontal bearing bracket 0504 is directly connected to the vertical bracket 0503 and rotates synchronously with the vertical bracket 0503 around the vertical bearing 0502. The inner ring of the horizontal bearing 0505 is fitted onto the horizontal bearing bracket 0504, and the outer ring is connected to the horizontal bracket 0506, so that the horizontal bracket 0506 can rotate relative to the horizontal bearing bracket 0504.

[0029] There are four reducer brackets 0508, which are installed on the chassis 0010 by fasteners and are symmetrically arranged on both sides of the vertical bearing bracket 0501. They are used to install and fix the reducer 0120 in the drive unit 0100. The reducer brackets 0508 connect the chassis 0010 and the housing of the reducer 0120.

[0030] This invention uses the vertical bearing bracket 0501 as the intermediate reference and defines the direction from the vertical bearing bracket 0501 to the two reducer brackets 0508 as "from inside to outside". The component structures on both sides of the vertical bearing bracket 0501 are distributed in a mirror symmetrical manner, and the subsequent orientation descriptions are based on this standard.

[0031] The drive unit 0100 provides a power source for the joint. There are two drive units, namely the first drive unit 0101 and the second drive unit 0102. They are arranged back-to-back mirror symmetrically along the same common axis and are located axially between the first drive bevel gear 0201 and the second drive bevel gear 0202. They are fixed on the chassis 0010 of the frame. Each drive unit 0100 consists of an external rotor permanent magnet synchronous motor 0110, a motor rotor connector 0111, a motor stator connector 0112, a motor bearing 0113, and a reducer 0120.

[0032] The motor rotor connector 0111 and the reducer 0120 are respectively fixed on both sides of the reducer bracket 0508, with the motor rotor connector located on the inner side of the reducer bracket 0508 (near the vertical bearing bracket 0501) and the reducer 0120 located on the outer side of the reducer bracket 0508.

[0033] Preferably, the permanent magnet synchronous motor 0110 is an external rotor frameless permanent magnet synchronous motor to achieve greater output torque and less weight; however, those skilled in the art should understand that the permanent magnet synchronous motor is not limited thereto. Without departing from the concept of this invention, other types of motors, such as internal rotor permanent magnet synchronous motors, axial flux motors, and other forms of rotary actuators, can be applied to this invention and achieve the same technical effects.

[0034] Preferably, the reducer 0120 is a harmonic reducer to achieve a larger reduction ratio and a smaller size and weight. However, those skilled in the art should understand that the reducer is not limited to this. Other types of reducers, such as RV reducers, planetary reducers, and other forms of reducers, can be applied to this invention without departing from the inventive concept and achieve the same technical effect. In this embodiment, the elastic spokes 0230 preferably have a straight shape and are arranged radially to facilitate processing and ensure sufficient tangential elasticity. However, those skilled in the art should understand that the elastic spokes are not limited to this form. Other shapes of elastic structures, such as springs, torsion springs, and other forms of elastic structures, can be applied to this invention without departing from the inventive concept and achieve the same technical effect.

[0035] The rotor of the permanent magnet synchronous motor 0110 is rigidly connected to the motor rotor connector 0111, such as by bolts. The stator is rigidly connected to the motor stator connector 0112. The motor bearing 0113 is installed inside the motor stator connector 0112, which allows the shaft of the motor rotor connector 0111 to be rotatably connected to the motor stator connector 0112. This restricts the rotor of the permanent magnet synchronous motor 0110 to only rotate, thus preventing radial offset.

[0036] The motor rotor connector 0111 is fixedly connected to the input end of the reducer 0120, transmitting the rotational motion generated by the permanent magnet synchronous motor 0110 to the reducer 0120; the housing of the reducer 0120 is fixedly connected to the reducer bracket 0508, and the output end is connected to the drive bevel gear 0200, which is used to reduce and increase the high-speed, low-torque motion output by the motor, converting it into low-speed, high-torque power that is transmitted to the drive bevel gear 0200.

[0037] Preferably, the permanent magnet synchronous motor 0110 adopts an external rotor frameless structure to obtain greater output torque with smaller weight and volume; the external rotor of the permanent magnet synchronous motor 0110 is directly connected to the input end of the reducer 0120 by bolts to reduce transmission gap and improve transmission efficiency.

[0038] The teeth of the output bevel gear 0400 mesh simultaneously with the teeth of the first drive bevel gear 0201 and the second drive bevel gear 0202. Its axis is perpendicular to the axes of the first drive bevel gear 0201 and the second drive bevel gear 0202. The output bevel gear 0400 is directly connected to the load. The output bevel gear 0400 is fixedly connected to the horizontal support 0506 and rotatably connected to the frame via connecting components such as the horizontal support 0506, horizontal bearing 0505, horizontal bearing bracket 0504, vertical support 0503, and vertical bearing 0502, enabling two-degree-of-freedom motion of pitch and rotation. The side of the output bevel gear 0400 away from the meshing end is directly connected to the load, transmitting power to the load. As mentioned above, the outer ring of the horizontal bearing 0505 is connected to the horizontal support 0506, allowing the horizontal support 0506 to rotate relative to the horizontal bearing bracket 0504. The output bevel gear 0400 is fixedly connected to the horizontal support 0506 and is sleeved on the outside of the horizontal bearing 0505. The horizontal support 0506 consists of an integrally connected connecting plate and an isolation plate, wherein the isolation plate is fixed in the inner ring of the connecting plate, and the horizontal bearing 0505 is in the inner ring of the isolation plate. The isolation plate is used to isolate the output bevel gear 0400 and the horizontal bearing 0505. The connecting plate and the output bevel gear 0400 are fixedly connected. The bearing cover plate 0507 is connected to the output bevel gear 0400 and is fixedly installed on the inner ring of the output bevel gear 0400 to limit the axial and radial positions of the horizontal bearing 0505 and prevent it from displacing.

[0039] Among them, the vertical bearing 0502 is responsible for bearing the pitching motion of the output bevel gear 0400, providing support and guidance for the pitching motion; the horizontal bearing 0505 is responsible for bearing the rotational motion of the output bevel gear 0400, providing support and guidance for the rotational motion.

[0040] The output bevel gear 0400 meshes with the teeth of the first drive bevel gear 0201 and the second drive bevel gear 0202 simultaneously. Its axis is perpendicular to the axes of the first and second drive bevel gears 0200. The output bevel gear 0400 is fixedly connected to the horizontal support 0506 and can be rotatably connected to the frame through connecting parts such as the horizontal support 0506, the horizontal bearing 0505, the horizontal bearing bracket 0504, the vertical support 0503, and the vertical bearing 0502, realizing two-degree-of-freedom motion of pitch and rotation. The side of the output bevel gear 0400 away from the meshing end is directly connected to the load, transmitting power to the load.

[0041] Among them, the vertical bearing 0502 is responsible for bearing the pitching motion of the output bevel gear 0400, providing support and guidance for the pitching motion; the horizontal bearing 0505 is responsible for bearing the rotational motion of the output bevel gear 0400, providing support and guidance for the rotational motion.

[0042] There are two drive bevel gears 0200, namely the first drive bevel gear 0201 and the second drive bevel gear 0202. They are arranged coaxially and located on the outer side (away from the vertical bearing bracket 0501) of the first drive unit 0101 and the second drive unit 0102, respectively. That is, the first drive unit 0101 and the second drive unit 0102 are axially located between the first drive bevel gear 0201 and the second drive bevel gear 0202. The first drive bevel gear 0201 and the second drive bevel gear 0202 are respectively connected to the output end (reducer 0120) of the first drive unit 0101 and the second drive unit 0102. The output end is fixedly connected to the motor rotor connector 0111 via a reducer 0120. Specifically, the input end of the reducer 0120 is connected to the output end of the motor rotor connector 0111. The output of the reducer 0120 is connected to the hubs 0210 of the first drive bevel gear 0201 and the second drive bevel gear 0202, allowing the first drive bevel gear 0201 and the second drive bevel gear 0202 to rotate following the first drive unit 0100 and the second drive unit 0100, respectively. The first drive bevel gear 0200 and the second drive bevel gear 0200 have elastic structures to provide passive compliance. The reducer 0120 slows down the rotational motion generated by the permanent magnet synchronous motor 0110, increasing the torque and driving the drive bevel gear 0200.

[0043] Each drive bevel gear 0200 includes a hub 0210, a rim 0220, and an elastic structure. The hub 0210 is the main structure of the drive bevel gear 0200, and the rim 0220 is arranged circumferentially around the periphery of the hub 0210. The elastic structure is installed between the rim 0220 and the hub 0210. The elastic structure provides passive compliance, and a deformation sensor 0300 is installed on the elastic structure to detect the elastic deformation of the elastic structure to determine the transmitted torque.

[0044] Some embodiments of the present invention are described below. Figure 4 and Figure 5The elastic structure is the elastic spoke 0230 of the driving bevel gear 0200, which connects the hub 0210 and the rim 0220 of the driving bevel gear 0200. The rim 0220 is arranged circumferentially along the driving bevel gear 0200, and the hub 0210 is a disc-shaped structure located at the center of the driving bevel gear 0200. There are four elastic spokes 0230, which are arranged symmetrically at 90° to each other and extend radially along the driving bevel gear 0200, with their two ends connected to the hub 0210 and the rim 0220 respectively. The elastic spokes 0230 are formed by machining multiple curved cuts on the disc-shaped substrate of the driving bevel gear 0200 through wire cutting or precision milling processes, and have good elastic deformation capability. The deformation sensing device 0300 is one or more strain gauges, which are attached to the surface of the elastic structure.

[0045] Some embodiments of the present invention are described below. Figure 6 The hub 0210 is located in the middle of the entire output bevel gear 0400, and the outer periphery is the rim 0220 that does not contact it. The hub 0210 and the rim 0200 are connected by multiple curved elastic spokes 0230.

[0046] Specifically, the elastic spokes 0230 are formed by machining multiple curved cuts using wire cutting or precision milling processes.

[0047] In some embodiments of the present invention, the hub 0210, the rim 0220 and the elastic structure can be integrally formed or assembled by splicing.

[0048] See Figure 4 and Figure 6 In a specific example, the hub 0210, the rim 0220, and the flexible spokes 0230 are composed of three structures that are integrally formed from the same metal blank.

[0049] See Figure 5 In another specific example, the drive bevel gear 0200 is composed of a hub 0210, a rim 0220, and an elastic spoke 0230, which are processed as independent components and then spliced ​​together. Since the joint mainly transmits tangential torque, in order to facilitate processing and assembly, the elastic spoke 0230 is installed in the preset slots of the hub 0210 and the rim 0220 through adhesive bonding or heat fitting processes to achieve a fixed connection between the three.

[0050] Preferably, the deformation sensing device 0300 for detecting the deformation of the elastic spokes 0230 comprises multiple strain gauges, which are attached to the surface of one or more elastic spokes 0230 to directly measure the surface strain caused by torsional deformation. The multiple strain gauges are configured as a half-bridge or full-bridge circuit of a Wheatstone bridge to improve measurement sensitivity and compensate for the effects of temperature changes. Those skilled in the art should understand that the deformation sensing device is not limited thereto. Without departing from the inventive concept, other types of sensors capable of detecting deformation, such as position encoders, optical variable sensors, and other devices capable of detecting angular changes between the hub 0210 and the rim 0220, can be applied to this invention and achieve the same technical effects.

[0051] The following is a further description with reference to the accompanying drawings.

[0052] like Figure 1 The figure shows a schematic diagram of the joint as a whole. The first drive unit 0101 and the second drive unit 0102 are located inside the whole, arranged back to back, with the output facing outwards. The first drive bevel gear 0201 and the second drive bevel gear 0202 are respectively located outside the two drive units 0100, and their inputs are directly connected to the outputs of the corresponding drive units. The output bevel gear 0400 meshes with both drive bevel gears 0200 simultaneously, forming a two-degree-of-freedom differential gear train. When the two drive bevel gears 0200 rotate simultaneously in one direction, the output bevel gear 0400 produces a pitching rotational motion, with the axis of rotation being the axis of the drive bevel gear 0200; when the two drive bevel gears 0200 rotate in opposite directions, the output bevel gear 0400 produces a rotational motion, with the axis of rotation being the axis of the output bevel gear 0400. The two drive units 0100 are fixed on the chassis 0010.

[0053] like Figure 4 The figure shows one embodiment of the drive bevel gear 0200 and a schematic diagram of its installation relationship with one embodiment of the deformation sensing device 0300. The drive bevel gear 0200 consists of a hub 0210, a rim 0220, and elastic spokes 0230, which are integrally connected. The hub 0210 serves as the main structure, with the rim 0220 located around its periphery. A groove is provided on the hub 0210 for mounting the elastic spokes 0230. Four elastic spokes 0230 are provided, arranged at 90° angles to each other. The elastic spokes 0230 are symmetrically arranged along the center of the chassis 0204, and radially arranged along the chassis 0204. Part of the elastic spokes are located in the groove on the hub 0210, and the other end abuts against the outer end of the chassis 0240. Figure 4In the illustrated embodiment, the drive bevel gear 0200 is integrally machined from a single metal blank. The elastic spokes 0230 are formed by machining multiple curved cuts into the disc-shaped substrate of the drive bevel gear 0200 using wire cutting or precision milling. The deformation sensing device 0300 in this embodiment consists of four strain gauges, each attached to one of the four elastic spokes 0230. The deformation of the elastic spokes 0230 can be detected by measuring the resistance of the deformation sensing device 0300, thereby estimating the magnitude of the torque transmitted by the drive bevel gear 0200.

[0054] like Figure 5 As shown, another embodiment of the drive bevel gear 0200 is illustrated. The drive bevel gear 0200 is composed of a hub 0210, a rim 0220, and elastic spokes 0230 spliced ​​together. Since it primarily transmits tangential torque, for ease of processing, the elastic spokes 0230 are connected at both ends to the hub 0210 and the rim 0220 respectively via adhesive bonding or heat fitting, and fixed in corresponding slots. In this connection method, notches are provided on the hub 0210 and the rim 0220 to allow the elastic spokes 0230 to be inserted, and the connection is achieved through adhesive bonding or heat fitting. Figure 5 In the embodiment of the drive bevel gear 0200, the deformation sensing device 0300 can be connected with... Figure 4 As in the embodiment, it is pasted onto the four elastic spokes 0230.

[0055] The specific working process of this invention is as follows: During operation, the first and second drive units 0100 located inside the joint serve as power sources. Specifically, when the external rotor permanent magnet synchronous motor 0110 is energized, its rotor drives the motor rotor connector 0111, which is rigidly connected to it, to rotate at high speed, thereby driving the input end of the reducer 0120 to rotate. The reducer 0120 reduces and amplifies the high-speed, low-torque output generated by the external rotor motor, converting it into low-speed, high-torque power output from its output end. The power reduced by the reducer 0120 directly drives the drive bevel gear 0200 connected to it.

[0056] In this process, the power is not rigidly transmitted directly from the reducer 0120 to the rim 0220 of the drive bevel gear 0200, but must pass through the elastic spokes 0230. When the load torque is applied, the elastic spokes 0230 undergo elastic deformation. This deformation achieves passive compliance on the one hand, absorbing instantaneous impacts in the transmission chain; on the other hand, the deformation sensing device 0300 attached to it synchronously senses this deformation and converts it into an electrical signal, thereby monitoring the magnitude of the currently transmitted torque in real time and realizing force perception.

[0057] After elastic transmission, the power ultimately reaches the rim 0220 of the drive bevel gear 0200. The joint adopts a differential layout, with the first and second drive bevel gears 0200 on both sides simultaneously meshing with the output bevel gear 0400 in the middle, forming a differential gear train. The final power output depends on the coordination of the drive units 0100 on both sides. Pitch motion: When the drive units 0100 on both sides drive the two drive bevel gears 0200 to rotate at the same speed and in the same direction, the driving torque is superimposed at the output bevel gear 0400, driving it to pitch around the horizontal axis, i.e., the axis of the drive bevel gear 0200. This motion is supported and guided by the vertical bearing 0502 and its support system 0501, 0503. Rotation motion: When the drive units 0100 on both sides drive the two drive bevel gears 0200 to rotate at the same speed but in opposite directions, the driving torque is converted into a torque that drives the output bevel gear 0400 to rotate around its own axis, realizing rotation. This motion is supported and guided by the horizontal bearing 0505 and its support system 0504, 0506, and 0507. Compound motion: When the speeds of the two drive units 0100 are not completely consistent, the output bevel gear 0400 will simultaneously generate a compound spatial motion of pitch and rotation.

[0058] In the description of this invention, 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," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention 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 the invention. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, "above" or "below" a second feature may include direct contact between the first and second features, or it may include contact between the first and second features not being in direct contact but through another feature between them.

[0059] In the description of this invention, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0060] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0062] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions, characterized in that, The application relates to a drive device for a load, comprising: a chassis (0010); two drive units (0100) arranged in a back-to-back mirror image along the same axis and fixedly arranged on the chassis (0010); two drive bevel gears (0200) respectively connected with the output ends of the two drive units (0100); an output bevel gear (0400) rotatably connected with the chassis (0010) through a connecting piece and simultaneously meshed with the two drive bevel gears (0200), the axis of the output bevel gear (0400) being perpendicular to the axes of the drive bevel gears (0200), and the output bevel gear (0400) being used for connecting a load; the two drive units (0100) being located between the two drive bevel gears (0200) along the axes; each drive bevel gear (0200) comprising a hub (0210) and a rim (0220) arranged circumferentially around the hub (0210), an elastic structure being arranged between the rim (0220) and the center of the hub (0210), and a deformation sensing device (0300) being arranged on the elastic structure.

2. The differential two-degree-of-freedom joint integrated with passive compliance and torque sensing functions according to claim 1, wherein, each drive unit (0100) comprising a permanent magnet synchronous motor (0110) and a speed reducer (0120), the rotor of the permanent magnet synchronous motor being connected with the input of the speed reducer (0120) through a motor rotor connecting piece (0111), and the output of the speed reducer (0120) being connected with the corresponding drive bevel gear (0200).

3. The differential two-DOF joint integrated with passive compliance and torque sensing functions according to claim 2, wherein, the rotor of the permanent magnet synchronous motor (0110) being connected with the speed reducer (0120) through the motor rotor connecting piece (0111), and the stator of the permanent magnet synchronous motor (0110) being connected with the motor bearing (0113) through the motor stator connecting piece (0112).

4. The differential two-DOF joint integrated with passive compliance and torque sensing functions according to claim 3, wherein, the chassis (0010) being fixedly provided with a speed reducer support (0508), and the motor rotor connecting piece (0111) and the speed reducer (0120) being arranged on the two sides of the speed reducer support (0508) respectively.

5. The integrated passive compliant and torque-sensing differential two-DOF joint of claim 1, wherein, the connecting piece comprising a vertical bearing support (0501) fixedly installed on the chassis (0010), a vertical bearing (0502) fixedly installed on the vertical bearing support (0501), the vertical bearing (0502) being sleeved in a vertical support (0503), and the outer end of the vertical support (0503) being connected with a horizontal bearing support (0504) used for installing the output bevel gear (0400).

6. The differential two-degree-of-freedom joint integrated with passive compliance and torque sensing functionality according to claim 5, wherein, the horizontal bearing support (0504) being sleeved in a horizontal bearing (0505), the horizontal bearing (0505) being sleeved in a horizontal support (0506), the output bevel gear (0400) being fixedly connected with the horizontal support (0506), and the output bevel gear (0400) being provided with a bearing cover plate (0507) limiting the movement of the horizontal bearing (0505).

7. The integrated passive compliant and torque-sensing differential two-DOF joint of claim 1, wherein, the elastic structure comprising a plurality of elastic spokes (0230) distributed circumferentially along the hub (0210), and the elastic spokes (0230) being in a straight line shape or a curve shape.

8. The integrated passive compliant and torque-sensing differential two-DOF joint of claim 1, wherein, the hub (0210), the rim (0220) and the elastic structure being integrally formed.

9. The integrated passive compliant and torque-sensing differential two-DOF joint of claim 1, wherein, The elastic structure is connected with the wheel rim (0220) and the center of the wheel hub (0210) by gluing or heat shrinkage.

10. A robot, characterized in that A differential two-degree-of-freedom joint integrating passive compliance and torque sensing functions as claimed in any one of claims 1 to 9.

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