A hybrid variable stiffness robotic arm joint

Abstract

The present invention provides a hybrid variable stiffness robotic arm joint, which has an outer shell and an inner shell, and a variable stiffness system arranged therebetween, the system comprising a shape memory alloy part and a blocking particle part, which enables the robotic arm to switch between rigidity and flexibility. The shape memory alloy part is composed of a shape memory alloy coil and a heating wire intertwined with each other, and the stiffness is adjusted by heating; the blocking particle part adjusts the particle arrangement state by air pressure. The sensing system includes a bending sensor and a flexible sleeve, which monitors the bending angle in real time and feeds back data, thereby improving the level of intelligence. The present invention designs a robotic arm joint with a dual variable stiffness mechanism by combining shape memory alloy and particle blocking technology. This mechanism enables the robotic arm to flexibly switch between flexibility and rigidity in different operating environments. The design simplifies the structure, reduces costs, enhances the safety of human-computer interaction, and is suitable for complex industrial and human-computer interaction scenarios.

Description

Technical Field

[0001] The present invention relates to a robot manipulator arm, in particular to a mixed-element variable-rigidity manipulator arm joint. Background Art

[0002] The flexibility and safety of robotic arms are crucial factors in the development of modern robotics. In many human-machine interaction scenarios, robotic arms must possess sufficient flexibility to adapt to complex environments and tasks, while also providing sufficient rigidity to perform high-precision or high-intensity operations when necessary. However, traditional robotic arm designs typically offer a trade-off between rigidity and flexibility, failing to achieve a flexible transition between these two characteristics within the same structure.

[0003] One solution of the prior art uses a bellows module and a built-in variable stiffness body as core components. The bellows module consists of an inner bellows and an outer bellows. A variable stiffness cavity is formed between the inner and outer layers, and the cavity is filled with multiple hard particle layers. These particle layers are connected by a flexible connecting layer and are tightly arranged under the action of negative pressure, thereby realizing active adjustment of the stiffness of the robotic arm. In specific operations, by controlling the air pressure in the main ventilation cavity, the bellows module of the robotic arm can realize telescopic movement; at the same time, by adjusting the size of the negative pressure in the variable stiffness cavity, the inner and outer bellows are pressed against the variable stiffness body, causing the particles in the hard particle layer to squeeze each other, thereby changing the stiffness of the robotic arm. This stiffness adjustment mechanism enables the robotic arm to quickly switch between flexibility and rigidity according to work requirements. Disadvantages of this existing solution:

[0004] 1. Response speed may be limited: Because this technology relies on air pressure regulation to change the stiffness of the robotic arm, the response speed may be limited by the air pressure control system. In some applications that require rapid stiffness changes, the response speed may not be fast enough, affecting the smoothness and accuracy of the operation.

[0005] 2. High system complexity: Involving multiple bellows modules, pneumatic control systems, and particle blocking structures, the overall structural complexity is high. This not only increases manufacturing difficulty and cost, but also makes system maintenance and debugging more cumbersome, potentially posing challenges to actual deployment in application scenarios.

[0006] 3. Limitations of the particle blocking effect: Although the particle blocking principle can effectively adjust stiffness, its performance may be limited by particle material, size, and pressure variations. Under high loads or extreme environments, the pure particle blocking effect may not be ideal, resulting in less precise or unstable stiffness adjustment.

[0007] 4. High airtightness requirements: This technology relies on a pneumatic system to adjust stiffness, which means the robotic arm must meet high airtightness requirements. Poor airtightness can lead to poor air pressure regulation, affecting the overall performance of the robotic arm. Furthermore, the pneumatic system may experience leakage and aging over time, impacting the reliability of the robotic arm.

[0008] Another solution in the prior art uses electrorheological fluid technology to achieve dynamic adjustment of the stiffness of the robotic arm. By installing a variable stiffness device inside the robotic arm module, the electrorheological fluid can be converted into liquid or solid at different voltages, thereby flexibly adjusting the stiffness of the robotic arm to meet the needs of different operating tasks. The robotic arm's ability to remain soft when high flexibility is required and quickly harden when high rigidity is required improves its adaptability in complex operating environments. In addition, multiple air cavities are set around the robotic arm module, and multi-degree-of-freedom movement is achieved through air pressure drive. These air cavities can be controlled independently, allowing the robotic arm to perform complex posture adjustments and bending operations. A modular design is adopted, and each variable stiffness robotic arm module is connected by connecting parts, which is convenient for disassembly and assembly, and has good portability and maintenance convenience. The robotic arm body is made of flexible material, and a spiral fiber structure is embedded in the outside to enhance its durability and anti-deformation ability, ensuring that the robotic arm can maintain stable performance under various operating conditions. Disadvantages of this existing solution:

[0009] 1. Limitations of Electrorheological Fluid Materials: The performance of electrorheological fluid is significantly affected by temperature, humidity, and electric field strength. In actual operation, changes in environmental conditions can lead to unstable stiffness adjustment effects of the electrorheological fluid. Furthermore, while electrorheological fluids offer a relatively fast response speed, they may not fully meet the requirements of applications requiring extremely high precision and fast response.

[0010] 2. High energy consumption: To maintain the stiffness regulation of the electrorheological fluid, the system needs to continuously supply voltage, which may lead to high energy consumption, especially in the case of long-term operation or high-frequency stiffness adjustment. This high energy consumption may become a limiting factor in some application scenarios, especially in portable or energy-constrained devices.

[0011] 3. Structural complexity and manufacturing cost: While the modular design allows for a certain degree of maintainability and portability, the overall structure remains relatively complex, particularly when it comes to the electrorheological fluid device, air chamber, and sealing system. Manufacturing and assembling these components can require high precision and cost, which can be challenging in large-scale production or cost-sensitive applications.

[0012] 4. Long-term reliability of sealing performance: Complex sealing systems are required to ensure the airtightness of the air cavity and variable stiffness device. However, seals may wear, age, or fail due to environmental factors over long-term use, which will directly affect the performance and reliability of the system. Maintaining and replacing these seals can increase operating and maintenance costs.

[0013] 5. Limited adaptability: Although soft robotic arms have strong adaptability, the durability of electrorheological fluid and flexible materials may be limited in certain extreme environments, such as high temperature, high pressure, or corrosive environments. In addition, complex external control systems may also have difficulty functioning properly under certain harsh conditions, limiting their application in specific fields.

[0014] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0015] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and provide a hybrid variable stiffness robotic arm joint.

[0016] To achieve the above object, the present invention adopts the following technical solutions:

[0017] A hybrid variable stiffness robotic arm joint, comprising:

[0018] The outer shell and the inner shell are made of flexible material;

[0019] A variable stiffness system is disposed between the outer shell and the inner shell, and is used to switch the robotic arm between rigid and flexible states; the variable stiffness system comprises a shape memory alloy portion and a blocking particle portion; the shape memory alloy portion comprises a shape memory alloy coil and a heating wire, the shape memory alloy coils being arranged to be intertwined, the heating wire being used to heat the shape memory alloy coils to achieve phase change and adjust the stiffness of the robotic arm, becoming rigid when heated and returning to softness when cooled; the blocking particle portion adjusts the arrangement of particles through air pressure to control the flexibility and rigidity of the joint;

[0020] The sensing system includes a bending sensor and a flexible sleeve. The flexible sleeve is arranged in the inner sleeve shell, and the bending sensor extends axially in the flexible sleeve to monitor the bending angle and deformation of the robotic arm in real time; the flexible sleeve serves as a buffer layer and transmits the bending angle to the bending sensor.

[0021] Furthermore, the shape memory alloy coil is in a sleeve shape, the heating wire is in a sleeve shape and is coaxially arranged with the shape memory alloy coil, and the blocking particle portion is in a sleeve shape and is arranged between the shape memory alloy coil and the outer shell.

[0022] Furthermore, a strip-shaped grid structure is provided inside the outer shell to effectively isolate the blocking particles and evenly distribute the particles inside the outer shell.

[0023] Furthermore, seals are provided at the ends of the outer shell and the inner shell to prevent blocking particles from falling out of the shell.

[0024] Furthermore, the heating wire is arranged in a reciprocating structure along the axial direction.

[0025] Furthermore, the inner shell is provided with air holes for letting in or exhausting gas.

[0026] Furthermore, a pair of clamping members are provided at the ends of the outer shell and the inner shell, and the clamping members are fastened by retaining members and screws to achieve a firm clamping of the robotic arm, and the robotic arm is connected to an external device through the clamping members.

[0027] Furthermore, the sensing system is composed of two bending sensors, and the bending sensors are fixed on the robotic arm through fixing parts.

[0028] Furthermore, the flexible material is rubber.

[0029] Furthermore, the flexible sleeve is a sponge sleeve.

[0030] The present invention has the following beneficial effects:

[0031] This paper proposes a hybrid variable-stiffness robotic arm joint that combines shape memory alloys with particle blocking technology. This design allows for switching between flexible and rigid robotic arm positions through external control, providing a more flexible solution for complex industrial and human-machine interaction scenarios. Furthermore, the robotic arm design incorporates a bend sensor that can detect changes in the arm's bending angle in real time, further enhancing the system's intelligence.

[0032] Compared with the prior art, the technical advantages of the present invention are mainly reflected in the following aspects:

[0033] This invention combines shape memory alloys with particle blocking technology to design a dual variable stiffness mechanism. This mechanism enables the robotic arm to flexibly switch between flexibility and rigidity in different operating environments. Shape memory alloy technology uses a heating wire to heat the shape memory alloy, increasing the rigidity of the robotic arm at high temperatures and restoring flexibility after cooling, thereby achieving a switch between high-precision operation and flexibility requirements. Particle blocking technology controls the arrangement of particles by adjusting the air pressure inside the robotic arm. The rigidity of the particles when they are tightly arranged is used to increase the hardness of the robotic arm, while the flexibility is restored when the particles are loosely arranged, enhancing the adaptability of the robotic arm in different tasks.

[0034] This invention incorporates an intelligent feedback system. By integrating a bending sensor into the robotic arm, it monitors the arm's bending angle in real time and feeds this data back to the system, ensuring high-precision posture control during complex tasks. This intelligent feedback system improves the robotic arm's precision and task execution efficiency.

[0035] This invention utilizes a hollow structure, which not only reduces the arm's weight but also provides space for integrating sensors and other components, enhancing its performance and adaptability in various mission scenarios. A sponge sleeve is embedded in the hollow section, and a built-in bending sensor provides accurate feedback, further improving the arm's performance in specific mission scenarios.

[0036] The overall structural design of the present invention is relatively simple, easy to manufacture and maintain, and reduces production costs. This simplified structural design makes the robot arm highly competitive in the market and provides a more flexible, safe and efficient solution for various complex operating environments.

[0037] The present invention particularly improves the safety of human-machine interaction by protecting the human operator by absorbing collision forces in a flexible state, while being able to quickly restore rigidity when needed to ensure the smooth completion of the operation task.

[0038] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a three-dimensional schematic diagram of the mixed variable stiffness robotic arm joint according to an embodiment of the present invention.

[0040] Figure 2 Schematic diagram of the decomposition structure of the variable stiffness system according to an embodiment of the present invention.

[0041] Figure 3 Schematic diagram of the exploded structure of the outer shell, inner shell and flexible sleeve according to an embodiment of the present invention.

[0042] Figure 4Schematic diagram of the exploded structure of the outer shell and the inner shell according to an embodiment of the present invention.

[0043] Figure 5 Schematic diagram of the structure of the outer shell of an embodiment of the present invention.

[0044] Figure 6 Schematic diagram of the structure of the inner shell of an embodiment of the present invention.

[0045] Figure 7 Schematic diagram of the decomposition structure of the variable stiffness system according to an embodiment of the present invention.

[0046] Figure 8 Schematic diagram of the structure of a single shape memory alloy according to an embodiment of the present invention.

[0047] Figure 9 Schematic diagram of the structure of the sensing system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0049] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0050] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0052] This paper proposes a hybrid variable-stiffness robotic arm joint that combines shape memory alloys with particle blocking technology. This design allows for switching between flexible and rigid robotic arm positions through external control, providing a more flexible solution for complex industrial and human-machine interaction scenarios. Furthermore, the robotic arm design incorporates a bend sensor that can detect changes in the arm's bending angle in real time, further enhancing the system's intelligence.

[0053] See Figures 1 to 9 The hybrid variable stiffness robotic arm joint of an embodiment of the present invention includes: an outer shell 11 and an inner shell 2, which are made of a flexible material such as rubber; a variable stiffness system, which is configured between the outer shell 1 and the inner shell 2, and is used to realize the switching of the robotic arm between the rigid and flexible states; the variable stiffness system includes a shape memory alloy part and a blocking particle part 5; the shape memory alloy part includes a shape memory alloy coil 3 and a heating wire 4, the shape memory alloy coil 3 is arranged to be intertwined, and the heating wire 4 is used to heat the shape memory alloy coil 3 to achieve phase change and adjust the stiffness of the robotic arm, becoming hard when heated and returning to softness when cooled; the blocking particle part 5 adjusts the arrangement state of the particles through air pressure to control the flexibility and stiffness of the joint; a sensing system, which includes a bending sensor 6 and a flexible sleeve 7, such as a sponge sleeve, the flexible sleeve 7 is arranged in the inner shell 2, and the bending sensor 6 extends axially in the flexible sleeve 7, and is used to monitor the bending angle and deformation of the robotic arm in real time; the flexible sleeve 7 serves as a buffer layer and transmits the bending angle to the bending sensor 6.

[0054] like Figures 1 to 9 As shown, in some preferred embodiments, the shape memory alloy coil 3 is in the shape of a sleeve, the heating wire 4 is in the shape of a sleeve and is arranged coaxially with the shape memory alloy coil 3, and the heating wire 4 is arranged in a reciprocating structure along the axial direction. The blocking particle portion 5 is in the shape of a sleeve and is arranged between the shape memory alloy coil 3 and the outer shell 1. A strip-shaped grid structure 9 is provided inside the outer shell 1 to effectively isolate the blocking particles and evenly distribute the particles inside the outer shell 1. Seals 10 are provided at the ends of the outer shell 1 and the inner shell 2 to prevent blocking particles from falling out of the shell. The inner shell 2 is provided with air holes 11 for the introduction or exhaust of gas. A pair of clamps 12 are provided at the ends of the outer shell 1 and the inner shell 2. The clamps 12 are fastened by retaining members 13 and screws to achieve a secure clamping of the robotic arm. The robotic arm is connected to external equipment through the clamps 12. The sensing system is composed of two bending sensors 6 spliced ​​together, and the bending sensor 6 is fixed to the robotic arm by fixing members 14.

[0055] Through innovative design, the present invention overcomes the limitations of traditional robotic arms in adjusting flexibility and rigidity. The present invention combines shape memory alloys with particle blocking technology, enabling the robotic arm joints to flexibly switch their rigidity in different working scenarios, thereby achieving higher operational adaptability. In a flexible state, the robotic arm can smoothly enter complex or narrow spaces, such as the inside of a pipe, and return to a rigid state by adjusting the rigidity to perform precise operational tasks. This technology greatly enhances the application potential of robotic arms in various industrial, medical, and service robotics fields. At the same time, the invention particularly improves the safety of human-machine interaction, protecting human operators by absorbing collision forces in a flexible state. In addition, the integrated bending sensor can monitor the bending angle of the robotic arm in real time, enhancing the intelligence level of the system and enabling it to complete more complex tasks. The joint structure design is relatively simple, with good manufacturing economy and operational feasibility. This design not only reduces production costs, but also provides a more flexible, safe, and efficient solution for various complex operating environments.

[0056] Specific embodiments of the present invention are further described below.

[0057] The overall design of the variable stiffness manipulator of the present invention can be divided into three main parts, namely the outer and inner shells, the variable stiffness system and the sensing system. Figures 1 to 9 shown.

[0058] The outer shell 1 and inner shell 2 form the external structure of the robotic arm. Made of flexible materials such as rubber, the outer shell 1 and inner shell 2 enable the robotic arm to exhibit soft-shell-like properties in normal operation. This design not only provides necessary mechanical protection but also enhances the robotic arm's flexibility, enabling it to remain safe and flexible when interacting with complex environments or the human body. Furthermore, this flexible shell structure allows the robotic arm to naturally adapt to the shape of its environment when static or under low load, minimizing potential damage to surrounding objects.

[0059] The variable stiffness system is a core element of the robotic arm. This system allows the arm to switch between rigid and flexible states to adapt to varying operational requirements. When high-precision or high-intensity operations are required, the variable stiffness system provides rigidity to ensure stability and accuracy. When safe and flexible operations or navigating confined spaces are required, the system reduces the arm's stiffness, allowing for greater flexibility. This ability to adjust stiffness gives the robotic arm immense adaptability in diverse application scenarios.

[0060] The sensing system empowers the robotic arm with perception capabilities. Equipped with high-precision bend sensors6, the system monitors the arm's bending angle and deformation in real time. These sensors feed data back to the system, enabling the arm to dynamically adjust based on its state, ensuring accurate and safe operation. The sensing system not only enhances the robotic arm's intelligence but also enables more precise control of its posture and movements during complex tasks, further improving operational efficiency.

[0061] case

[0062] The housing is primarily composed of an outer rubber shell 1 and an inner rubber shell 2. The entire structure is manufactured using 3D printing technology to ensure structural precision and stability. This 3D-printed housing design allows the robotic arm to flexibly adapt to different geometric shapes and sizes during the manufacturing process, while ensuring uniform material distribution and overall arm quality.

[0063] At the housing ends, two rigid clamping members 12 are provided, which are fixed and screwed by retaining members 13 to secure the robotic arm. These members can be used to secure the robotic arm and connect it to external equipment.

[0064] A specially designed striped grid structure 9 is incorporated into the outer shell 1 to effectively isolate the obstructed particle portion 5. This design addresses the uneven weight distribution that can result from particle accumulation within the shell, thereby preventing the deterioration of the robot arm's stiffness adjustment due to uneven weight distribution. The grid structure 9 evenly distributes particles within the shell, ensuring consistent and reliable performance during variable stiffness operation.

[0065] The inner shell 2 is designed with an air hole 11 to allow an air pipe to be inserted therein for internal exhaust of gas.

[0066] The housing is also equipped with a seal 10, which prevents obstructing particles from falling out of the housing, ensuring the overall structural stability of the robotic arm. This sealing design not only extends the service life of the robotic arm but also prevents performance degradation or operational failure caused by particle leakage during operation, maintaining the long-term reliability of the robotic arm. An outer cover 8 is also provided at the end of the housing.

[0067] Variable stiffness system

[0068] The variable stiffness system utilizes a hybrid variable stiffness design combining shape memory alloys and blocking particles, aiming to provide the robotic arm with flexible and reliable stiffness adjustment capabilities. These two variable stiffness technologies, each with its own unique operating mechanism, are cleverly combined to enable the robotic arm to freely switch between rigidity and flexibility in response to varying operating environments and task requirements.

[0069] The shape memory alloy part utilizes the unique properties of shape memory alloy materials under temperature changes. The system contains a coil 3 ( Figure 8 A single shape memory alloy 15 is shown), and these coils 3 are carefully designed to be intertwined to ensure optimal structural stability and deformation ability during operation. In the middle of the coil 3, the heating wire 4 is arranged in a reciprocating structure. When the heating wire 4 is energized, it heats up rapidly, thereby heating the surrounding shape memory alloy coils 3. As the temperature rises, the shape memory alloy undergoes a phase change and becomes more rigid, thereby significantly improving the stiffness of the robotic arm. This increase in stiffness enables the robotic arm to provide the required support force in high-precision operations or heavy-load tasks. When the heating wire 4 is de-energized and cooled, the shape memory alloy returns to a soft state, reducing the stiffness of the robotic arm and showing greater flexibility, making it suitable for completing tasks that require flexibility and safety.

[0070] The particle blocking effect generated by the blocking particle section 5 further enhances the stiffness adjustment capability of the robot arm. These blocking particles are evenly distributed within the internal structure of the robot arm, and through precise layout design, the particles are evenly distributed throughout the robot arm. When the system is started and negative pressure is applied to the interior of the robot arm, the particles are compressed and tightly packed. This dense arrangement significantly improves the stiffness of the robot arm, enabling it to exhibit excellent performance in operations requiring high-rigidity support. Conversely, when positive pressure is applied to the system, the particles are relatively loosely arranged, restoring the flexibility of the robot arm and facilitating flexible movement and operation in narrow or complex operating environments.

[0071] By combining these two variable stiffness methods, the present invention achieves dynamic adjustment of the robotic arm's stiffness. This hybrid variable stiffness design not only grants the robotic arm flexibility in a wide range of applications, but also ensures its reliability in high-load and high-precision operations. Whether in situations requiring soft touch or tasks requiring rigid support, the robotic arm can adjust its stiffness based on the task requirements, completing the operation in the most optimal state. The design of this variable stiffness system greatly expands the application range of the robotic arm, enabling it to handle more diverse and complex operational tasks.

[0072] Sensing system

[0073] The sensing system consists of two bend sensors 6, securely mounted to the robotic arm via fixtures 14, ensuring accurate detection of bending angles during movement. A flexible sleeve 7, such as a sponge, is also incorporated into the system as a buffer layer. When the robotic arm bends, the sponge accurately transmits the bending angle to the sensor, ensuring that the sensor accurately reflects the actual posture of the robotic arm in real time. This sensing system design not only improves the robotic arm's precision and responsiveness, but also provides strong support for dynamic adjustment and posture control during complex tasks, ensuring operational reliability and safety.

[0074] The present invention has the following features and advantages: 1. Dual variable stiffness mechanism: By combining shape memory alloys and particle blocking technology, the present invention achieves wide-range adjustable stiffness of the robotic arm. The shape memory alloy stiffens the joints when heated and softens when cooled; the particle blocking technology further controls the flexibility and stiffness of the joints through air pressure regulation. This dual variable stiffness mechanism allows the robotic arm to freely switch its mechanical properties in different operating environments. 2. High adaptability and flexibility: The robotic arm, in its flexible state, can adapt to complex and confined operating environments, such as those within pipelines. When high-precision or high-rigidity operations are required, the robotic arm can quickly return to its rigid state, ensuring operational stability. 3. Human-machine interaction safety: In the event of a collision, the robotic arm prioritizes impact absorption, minimizing harm to humans. When necessary, the robotic arm can restore its rigidity by heating the shape memory alloy, ensuring smooth completion of the task. This feature significantly improves the reliability of the robotic arm in safety-critical applications. 4. Intelligent feedback system: The present invention integrates bending sensors into the joints of the robotic arm. These sensors detect the bending angle of the robotic arm in real time and provide feedback to the control system. This can improve the accuracy and efficiency of task execution. 5. The versatility of the hollow design: The hollow structure of the robotic arm not only reduces the overall weight, but also provides space for internal integrated sensors and other components. For example, the hollow part is embedded with a sponge sleeve, and the built-in bending sensor can provide accurate feedback information, further improving the performance of the robotic arm in specific task scenarios. 6. Simple structure and easy to manufacture: Although the present invention combines a variety of advanced technologies, its overall structural design is relatively simple. This enables the robotic arm to maintain high economy and operability during the manufacturing process, reduce costs, and is easy to maintain.

[0075] In summary, compared with the prior art, the present invention has the following significant innovative features and advantages:

[0076] First, the core design of this invention lies in the use of a dual variable stiffness mechanism, which combines shape memory alloy technology and particle blocking technology. Shape memory alloy technology uses electric heating wire to harden the alloy at high temperatures, thereby increasing the stiffness of the robot arm, and then restores flexibility after cooling. This property enables the robot arm to flexibly switch between environments requiring high-precision operation and flexible adaptability. Particle blocking technology controls the arrangement of particles by adjusting the internal air pressure, thereby adjusting the stiffness of the robot arm. This design enhances the adaptability of the robot arm when performing different tasks.

[0077] Secondly, the invention further enhances the performance of the robotic arm through an intelligent feedback system. This system integrates a bending sensor to monitor the arm's bending angle in real time and feeds this critical data back to the control system, ensuring high-precision posture control when performing complex tasks.

[0078] In addition, the hollow structure design of the present invention not only reduces the weight of the robotic arm, but also provides space for the integration of sensors and other components. Such a design not only optimizes the function of the robotic arm, but also ensures its efficient operation in various tasks.

[0079] Furthermore, the present invention simplifies and modularizes the structural design, which makes the robotic arm easier to manufacture and maintain, thereby improving the economy and operability of the entire system.

[0080] Moreover, the present invention also improves the safety of human-machine interaction by protecting the human operator by absorbing the collision force in a flexible state, while being able to quickly restore rigidity when needed to ensure the smooth completion of the operation task.

[0081] The present invention significantly improves the performance of the robotic arm and provides a more flexible, safe and efficient solution for various complex operating environments.

[0082] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these 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 any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A hybrid variable stiffness robotic arm joint, characterized in that: include: The outer shell and the inner shell are made of flexible material; A variable stiffness system is disposed between the outer shell and the inner shell, and is used to switch the robotic arm between rigid and flexible states; the variable stiffness system comprises a shape memory alloy portion and a blocking particle portion; the shape memory alloy portion comprises a shape memory alloy coil and a heating wire, the shape memory alloy coils being arranged to be intertwined, the heating wire being used to heat the shape memory alloy coils to achieve phase change and adjust the stiffness of the robotic arm, becoming rigid when heated and returning to softness when cooled; the blocking particle portion adjusts the arrangement of particles through air pressure to control the flexibility and rigidity of the joint; The sensing system includes a bending sensor and a flexible sleeve. The flexible sleeve is arranged in the inner sleeve shell, and the bending sensor extends axially in the flexible sleeve to monitor the bending angle and deformation of the robotic arm in real time; the flexible sleeve serves as a buffer layer and transmits the bending angle to the bending sensor.

2. The hybrid variable stiffness manipulator joint according to claim 1, characterized in that: The shape memory alloy coil is in a sleeve shape, the heating wire is in a sleeve shape and is coaxially arranged with the shape memory alloy coil, and the blocking particle portion is in a sleeve shape and is arranged between the shape memory alloy coil and the outer shell.

3. The hybrid variable stiffness manipulator joint according to claim 1, characterized in that: A strip-shaped grid structure is provided inside the outer shell to effectively isolate the blocking particles and evenly distribute the particles inside the outer shell.

4. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: The ends of the outer shell and the inner shell are provided with sealing members for preventing blocking particles from falling out from the interior of the shell.

5. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: The heating wire is arranged in a reciprocating structure along the axial direction.

6. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: The inner shell is provided with air holes for letting in or exhausting gas.

7. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: A pair of clamping members are provided at the ends of the outer shell and the inner shell. The clamping members are fastened by retaining members and screws to achieve firm clamping of the robotic arm. The robotic arm is connected to external equipment through the clamping members.

8. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: The sensing system is composed of two bending sensors, which are fixed on the robotic arm via a fixing piece.

9. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: The flexible material is rubber.

10. The hybrid variable stiffness manipulator joint according to any one of claims 1 to 3, characterized in that: The flexible sleeve is a sponge sleeve.

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