Mixed-element variable-stiffness mechanical arm joint

Abstract

The invention provides a mixed-element variable-rigidity mechanical arm joint which is provided with an outer sleeve shell, an inner sleeve shell and a variable-rigidity system arranged between the outer sleeve shell and the inner sleeve shell, the variable-rigidity system comprises a shape memory alloy part and a particle blocking part, and switching between rigidity and flexibility of a mechanical arm is achieved. The shape memory alloy part is composed of a shape memory alloy coil and an electric heating wire which are wound mutually, and the rigidity is adjusted through heating. And the particle blocking part adjusts the particle arrangement state through air pressure. The sensing system comprises a bending sensor and a flexible sleeve, the bending angle is monitored in real time, data are fed back, and the intelligent level is improved. According to the mechanical arm joint, the shape memory alloy and the particle blocking technology are combined, and the mechanical arm joint with the dual variable stiffness mechanism is designed. By means of the mechanism, the mechanical arm can be flexibly switched between flexibility and rigidity in different operation environments. The design simplifies the structure, reduces the cost, enhances the man-machine interaction safety, and is suitable for complex industries and man-machine interaction scenes.

Description

Technical Field

[0001] The invention relates to a robot mechanical arm, in particular to a mixed element variable stiffness mechanical arm joint. Background Art

[0002] In the development of modern robotics, the flexibility and safety of robotic arms are crucial factors. In many human-machine interaction scenarios, robotic arms need to be flexible enough to adapt to complex environments and tasks, while providing sufficient rigidity to perform high-precision or high-intensity operations when necessary. However, traditional robotic arm designs can usually only make a trade-off between rigidity and flexibility, and cannot achieve flexible conversion between these two characteristics in 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 is composed 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 connection layer and are tightly arranged under the action of negative pressure, thereby realizing active adjustment of the stiffness of the robot arm. In specific operation, by controlling the air pressure in the main ventilation cavity, the bellows module of the robot arm can realize telescopic movement; at the same time, by adjusting 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 robot arm. This stiffness adjustment mechanism enables the robot arm to quickly switch between flexibility and rigidity according to work requirements. Disadvantages of this existing solution:

[0004] 1. Response speed may be limited: Since this technology relies on air pressure regulation to change the stiffness of the robot arm, the response speed may be limited by the air pressure control system. In some application scenarios that require rapid stiffness changes, it may not be possible to achieve a fast enough response speed, thus 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 structure is highly complex. This not only increases the difficulty and cost of manufacturing, but also makes system maintenance and debugging more cumbersome, which may pose challenges to the actual deployment of application scenarios.

[0006] 3. Limitations of particle blocking effect: Although the particle blocking principle can effectively adjust stiffness, its performance may be limited by particle material, size and pressure changes. Under high load or extreme environment, the pure particle blocking effect may not be ideal, resulting in inaccurate stiffness adjustment or insufficient stability.

[0007] 4. High air tightness requirements: This technology relies on the pneumatic system to achieve stiffness adjustment, which means that the air tightness requirements of the robot arm are high. If the air tightness is not good, it may lead to poor air pressure adjustment, which in turn affects the overall performance of the robot arm. In addition, the pneumatic system may face problems such as leakage and aging during long-term use, affecting the reliability of the robot arm.

[0008] Another solution of the prior art uses electrorheological fluid technology to achieve dynamic adjustment of the stiffness of the robot arm. Through the variable stiffness device set inside the robot arm module, the electrorheological fluid can be converted into liquid or solid at different voltages, so as to flexibly adjust the stiffness of the robot arm to meet the needs of different operating tasks. The ability of the robot arm to remain soft when high flexibility is required and to harden quickly when high rigidity is required improves its adaptability in complex operating environments. In addition, multiple air cavities are set around the robot arm module, and multi-degree-of-freedom movement is achieved through air pressure drive. These air cavities can be controlled independently, allowing the robot arm to perform complex posture adjustments and bending operations. A modular design is adopted, and each variable stiffness robot arm module is connected by connecting parts, which is convenient for disassembly and assembly, and has good portability and maintenance convenience. The robot 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 robot 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 greatly affected by temperature, humidity and electric field strength. In actual operation, changes in environmental conditions may cause the stiffness adjustment effect of electrorheological fluid to be unstable. In addition, although the response speed of electrorheological fluid is fast, it may not fully meet the requirements in applications that require extremely high precision and fast response.

[0010] 2. High energy consumption: In order to maintain the stiffness regulation of the electrorheological fluid, the system needs to continuously provide voltage, which may lead to high energy consumption, especially in the case of long-term operation or high-frequency adjustment of stiffness. 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: Although the modular design makes the system maintainable and portable to a certain extent, the overall structure is still relatively complex, especially the parts involving the electrorheological fluid device, air cavity and sealing system. The manufacture and assembly of these parts may require high precision and cost, which may become a challenge in large-scale production or cost-sensitive application scenarios.

[0012] 4. Long-term reliability of sealing performance: A complex sealing system is relied upon to ensure the airtightness of the air cavity and the variable stiffness device. However, the seals may be worn, aged, or fail due to environmental factors during long-term use, which will directly affect the performance and reliability of the system. Maintaining and replacing these seals may increase operating and maintenance costs.

[0013] 5. Limited adaptability: Although the soft robotic arm has strong adaptability, the durability of electrorheological fluid materials 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 working 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 for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the 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 mechanical arm joint, comprising:

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

[0019] A variable stiffness system, which is arranged between the outer shell and the inner shell, and is used to realize the switching of the robot arm between the rigid and flexible states; the variable stiffness system includes a shape memory alloy part and a blocking particle part; the shape memory alloy part includes a shape memory alloy coil and a heating wire, the shape memory alloy coil is arranged to be intertwined, and the heating wire is used to heat the shape memory alloy coil to realize phase change and adjust the stiffness of the robot arm, becoming hard when heated and returning to softness when cooled; the blocking particle part adjusts the arrangement state of particles through air pressure to control the flexibility and rigidity of the joint;

[0020] The sensing system comprises a bending sensor and a flexible sleeve, wherein the flexible sleeve is arranged in the inner sleeve shell, and the bending sensor extends axially in the flexible sleeve for real-time monitoring of the bending angle and deformation of the robot arm; 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 body to effectively isolate the blocking particles and make the particles evenly distributed inside the outer shell body.

[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 body 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 sensor is fixed on the robot arm through a fixing piece.

[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] The present invention proposes a hybrid variable stiffness robotic arm joint, which combines shape memory alloy and particle blocking technology, and can realize the flexible and rigid switching of the robotic arm through external control, providing a more flexible solution for complex industrial and human-machine interaction scenarios. In addition, the robotic arm design also integrates a bending sensor, which can sense the bending angle changes of the robotic arm in real time, further improving the intelligence level of the system.

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

[0033] The present invention designs a dual variable stiffness mechanism by combining shape memory alloy and particle blocking technology. This mechanism enables the robot arm to flexibly switch between flexibility and rigidity in different operating environments. Shape memory alloy technology uses electric heating wire to heat shape memory alloy, so that the robot arm increases rigidity at high temperature and restores flexibility after cooling, thereby switching between high-precision operation and flexibility requirements. Particle blocking technology controls the arrangement state of particles by adjusting the air pressure inside the robot arm, uses the rigidity when the particles are closely arranged to improve the hardness of the robot arm, and restores flexibility when the particles are loosely arranged, thereby enhancing the adaptability of the robot arm in different tasks.

[0034] The present invention integrates an intelligent feedback system, which monitors the bending angle of the robotic arm in real time by integrating a bending sensor in the robotic arm, and feeds the data back to the system to ensure high-precision posture control of the robotic arm in complex tasks. This intelligent feedback system improves the accuracy of the robotic arm and the efficiency of task execution.

[0035] The present invention adopts a hollow structure design, which not only reduces the weight of the robot arm, but also provides space for internal integrated sensors and other components, enhancing the performance and adaptability of the robot arm in various mission scenarios. 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 robot arm 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 operating 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 It is a three-dimensional schematic diagram of a hybrid variable stiffness robotic arm joint according to an embodiment of the present invention.

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

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

[0042] Figure 4It is a schematic 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 decomposed 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] Fig. 9 Schematic diagram of the structure of the sensor 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 and application of the present invention.

[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 fixing as well as for coupling or communication.

[0050] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0052] The present invention proposes a hybrid variable stiffness robotic arm joint, which combines shape memory alloy and particle blocking technology, and can realize the flexible and rigid switching of the robotic arm through external control, providing a more flexible solution for complex industrial and human-machine interaction scenarios. In addition, the robotic arm design also integrates a bending sensor, which can sense the bending angle changes of the robotic arm in real time, further improving the intelligence level of the system.

[0053] See also Figures 1 to 9 The hybrid variable stiffness mechanical arm joint of the embodiment of the present invention comprises: 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 arranged between the outer shell 1 and the inner shell 2, and is used to realize the switching of the mechanical arm between the rigid and flexible states; the variable stiffness system comprises a shape memory alloy part and a blocking particle part 5; the shape memory alloy part comprises 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 realize phase change and adjust the stiffness of the mechanical arm, harden when heated, and restore softness when cooled; the blocking particle part 5 adjusts the arrangement state of the particles by air pressure to control the flexibility and rigidity of the joint; a sensing system, which comprises 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 mechanical 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 coaxially arranged 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 part 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 arranged inside the outer shell 1 to effectively isolate the blocking particles and evenly distribute the particles inside the outer shell 1. A seal 10 is provided at the end of the outer shell 1 and the inner shell 2 to prevent the blocking particles from falling out of the shell. The inner shell 2 is provided with an air hole 11 for passing or exhausting gas. A pair of clamps 12 are provided at the ends of the outer shell 1 and the inner shell 2, and the clamps 12 are fastened by a retainer 13 and a screw to achieve a firm clamping of the robot arm, and the robot arm is connected to an external device through the clamp 12. The sensing system is composed of two bending sensors 6 spliced ​​together, and the bending sensor 6 is fixed on the robot arm through a fixing member 14.

[0055] The present invention solves the limitations of traditional robotic arms in adjusting flexibility and rigidity through innovative design. The present invention combines shape memory alloys and particle blocking technology to enable 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 operating tasks. This technology greatly improves the application potential of robotic arms in various industrial, medical and service robotic fields. At the same time, the invention particularly improves the safety of human-machine interaction by absorbing collision forces in a flexible state to protect human operators. In addition, the integrated bending sensor can monitor the bending angle of the robotic arm in real time, improve the intelligence level of the system, and enable it to complete more complex tasks. The joint structure design is relatively simple and has 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] The specific embodiments of the present invention are further described below.

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

[0058] The outer shell 1 and the inner shell 2 constitute the external structure of the robot arm. The outer shell 1 and the inner shell 2 are made of flexible materials such as rubber, so that the robot arm exhibits soft-body-like characteristics under normal conditions. This design not only provides the necessary mechanical protection, but also enhances the flexibility of the robot arm, allowing it to remain safe and soft when interacting with complex environments or the human body. Moreover, this flexible shell structure enables the robot arm to naturally adapt to the shape of the environment in a static or low-load state, and can reduce potential damage to surrounding objects.

[0059] The variable stiffness system is one of the core elements of the robot arm. Through this system, the robot arm can switch back and forth between rigid and flexible states to adapt to different operational requirements. When high-precision or high-intensity operations are required, the variable stiffness system can make the robot arm rigid to ensure stability and precision; when safe and flexible operations or passing through narrow spaces are required, the system can reduce the stiffness of the robot arm to make it more flexible. This ability to adjust stiffness gives the robot arm great adaptability in a variety of application scenarios.

[0060] The sensing system gives the robot arm the ability to perceive. The system is equipped with high-precision bending sensors6 that can monitor the bending angle and deformation of the robot arm in real time. These sensors feed data back to the system, allowing the robot arm to dynamically adjust according to its own status to ensure the accuracy and safety of operation. The sensing system not only improves the intelligence level of the robot arm, but also enables it to more accurately control its posture and movements in the execution of complex tasks, further improving operational efficiency.

[0061] case

[0062] The shell part is mainly composed of an outer shell 1 and an inner shell 2 made of rubber material. The entire body is made using 3D printing technology to ensure the accuracy and stability of the structure. This 3D printed shell design allows the robot arm to flexibly adapt to different geometric shapes and size requirements during the manufacturing process, while ensuring the uniform distribution of materials and the overall quality of the robot arm.

[0063] At the end of the housing, two rigid clamping members 12 are provided, which are fixed by retaining members 13 and fastened with screws, thereby achieving a firm clamping of the mechanical arm. The mechanical arm can be fixed by these members and connected to external equipment.

[0064] A strip-shaped grid structure 9 is specially designed inside the outer shell 1 to effectively isolate the blocked particle part 5. This design solves the problem of uneven weight that may be caused by the accumulation of particles in the shell, thereby avoiding the situation where the mechanical arm stiffness change effect is deteriorated due to uneven weight distribution. Through the grid structure 9, the particles are evenly distributed inside the shell, ensuring the performance consistency and reliability of the mechanical arm in the variable stiffness operation.

[0065] The inner shell 2 is designed with an air hole 11 to allow an air pipe to be inserted therein so as to discharge gas inside.

[0066] In addition, the housing is also equipped with a seal 10, which is used to prevent blocking particles from falling out of the housing and ensure that the overall structure of the robot arm remains stable. The sealing design not only increases the service life of the robot arm, but also prevents performance degradation or operation failure caused by particle leakage during operation, thereby maintaining the long-term reliability of the robot arm. An outer shell cover 8 is also provided at the end of the housing.

[0067] Variable stiffness system

[0068] The variable stiffness system adopts a hybrid variable stiffness design combining shape memory alloy and blocking particles, aiming to provide the robot arm with flexible and reliable stiffness adjustment capabilities. These two variable stiffness technologies each have their own unique working mechanism, and through clever combination, the robot arm can freely switch between rigidity and flexibility under different working 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 will heat up rapidly, thereby heating the surrounding shape memory alloy coils 3. As the temperature rises, the shape memory alloy will undergo a phase change and become 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 powered off and cooled, the shape memory alloy will return to a soft state, reducing the stiffness of the robotic arm and showing greater flexibility, which is suitable for completing tasks that require flexibility and safety.

[0070] The particle blocking effect generated by the blocking particle part 5 further enhances the stiffness adjustment capability of the robot arm. These blocking particles are evenly distributed in the internal structure of the robot arm, and the particles are evenly distributed in various parts of the robot arm through precise layout design. When the system is started and a vacuum pressure is applied to the inside of the robot arm, the particles are compressed and tightly arranged. This dense arrangement significantly improves the stiffness of the robot arm, allowing it to perform excellent performance in operations that require high stiffness support. Conversely, when a positive pressure is applied inside the system, the particles are relatively loosely arranged, restoring the flexibility of the robot arm, making it easier to move and operate flexibly in narrow or complex operating environments.

[0071] Through the combination of these two variable stiffness methods, the present invention realizes the dynamic adjustment of the stiffness of the robot arm. This hybrid variable stiffness design not only gives the robot arm flexibility in a wide range of application scenarios, but also ensures its reliability in high-load and high-precision operations. Whether in situations that require soft touch or in tasks that require rigid support, the robot arm can adjust its own stiffness according to task requirements and complete the operation task in the most suitable state. The design of this variable stiffness system greatly expands the application range of the robot arm, enabling it to be competent for more diverse and complex operation tasks.

[0072] Sensing system

[0073] The sensing system is composed of two bending sensors 6, which are firmly mounted on the robot arm through a fixing 14 to ensure that it can accurately capture the bending angle during the movement of the robot arm. A flexible sleeve 7 such as a sponge sleeve is also designed in the system as a buffer layer. When the robot arm bends, the sponge sleeve can accurately transmit the bending angle to the sensor, thereby ensuring that the sensor can reflect the actual posture of the robot arm in real time and accurately. The design of this sensing system not only improves the accuracy and response speed of the robot arm, but also provides strong support for dynamic adjustment and posture control in complex tasks, ensuring the reliability and safety of operation.

[0074] The present invention has the following characteristics and advantages: 1. Dual variable stiffness mechanism: By combining shape memory alloy and particle blocking technology, the present invention realizes a wide range of adjustable stiffness of the robot arm. Shape memory alloy makes the joint hard when heated and restores softness when cooled; particle blocking technology further controls the flexibility and rigidity of the joint through air pressure regulation. This dual variable stiffness mechanism allows the robot arm to freely switch its mechanical properties in different operating environments. 2. High adaptability and flexibility: The robot arm can adapt to complex and narrow operating environments in a flexible state, such as operating in a pipeline. When high-precision or high-rigidity operation is required, the robot arm can quickly restore the rigid state to ensure the stability of the operation. 3. Human-machine interaction safety: In the event of a collision, the robot arm can preferentially absorb the impact force to reduce damage to humans. When necessary, the robot arm can restore rigidity by heating the shape memory alloy to ensure the smooth completion of the operation task. This feature greatly improves the reliability of the robot arm in application scenarios with high safety requirements. 4. Intelligent feedback system: The present invention integrates bending sensors in the joints of the robot arm, which can detect the bending angle of the robot arm in real time and feed back the data to the control system. This can improve the accuracy and efficiency of task execution. 5. Versatility of 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, a sponge sleeve is embedded in the hollow part, 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 of all, the core design of the present invention is to adopt a dual variable stiffness mechanism, which combines shape memory alloy technology and particle blocking technology. Shape memory alloy technology uses electric heating wire to make the alloy harden at high temperature, thereby increasing the stiffness of the robot arm, and restores flexibility after cooling. This feature enables the robot arm to flexibly switch between environments that require high-precision operation and flexible adaptation. Particle blocking technology controls the arrangement state 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 improves the performance of the robot arm through an intelligent feedback system. This system integrates a bending sensor to monitor the bending angle of the robot arm in real time and feeds this key data back to the control system, ensuring that the robot arm can achieve 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 robot arm easier to manufacture and maintain, thereby improving the economy and operability of the entire system.

[0080] Moreover, the present invention also particularly 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 robot arm and provides a more flexible, safe and efficient solution for various complex operating environments.

[0082] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. 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 can 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, which is arranged between the outer shell and the inner shell, and is used to realize the switching of the robot arm between the rigid and flexible states; the variable stiffness system includes a shape memory alloy part and a blocking particle part; the shape memory alloy part includes a shape memory alloy coil and a heating wire, the shape memory alloy coil is arranged to be intertwined, and the heating wire is used to heat the shape memory alloy coil to realize phase change and adjust the stiffness of the robot arm, becoming hard when heated and returning to softness when cooled; the blocking particle part adjusts the arrangement state of particles through air pressure to control the flexibility and rigidity of the joint; The sensing system comprises a bending sensor and a flexible sleeve, wherein the flexible sleeve is arranged in the inner sleeve shell, and the bending sensor extends axially in the flexible sleeve for real-time monitoring of the bending angle and deformation of the robot arm; the flexible sleeve serves as a buffer layer and transmits the bending angle to the bending sensor.

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

3. The hybrid variable stiffness mechanical arm joint according to claim 1 or 2, characterized in that: A strip-shaped grid structure is arranged inside the outer shell to effectively isolate the blocking particles and evenly distribute the particles inside the outer shell.

4. The hybrid variable stiffness mechanical arm 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 inside of the shell.

5. The hybrid variable stiffness mechanical arm joint according to any one of claims 1 to 4, characterized in that: The heating wire is arranged in a reciprocating structure along the axial direction.

6. The hybrid variable stiffness mechanical arm joint according to any one of claims 1 to 5, characterized in that: The inner shell is provided with air holes for letting in or exhausting gas.

7. The hybrid variable stiffness mechanical arm joint according to any one of claims 1 to 6, 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 a firm clamping of the robot arm. The robot arm is connected to an external device through the clamping members.

8. The hybrid variable stiffness mechanical arm joint according to any one of claims 1 to 7, characterized in that: The sensing system is composed of two bending sensors, and the bending sensors are fixed on the mechanical arm through a fixing piece.

9. The hybrid variable stiffness mechanical arm joint according to any one of claims 1 to 8, characterized in that: The flexible material is rubber.

10. The hybrid variable stiffness mechanical arm joint according to any one of claims 1 to 9, characterized in that: The flexible sleeve is a sponge sleeve.

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