A dual-segment tendon sheath driven rigid-flexible manipulator

Abstract

This utility model discloses a dual-segment tendon sheath-driven rigid-flexible manipulator, comprising a base, a drive component, a proximal finger, a distal finger, and a tendon sheath transmission system. By configuring the drive component, proximal finger, distal finger, and tendon sheath transmission system, a unique hybrid structure of spring and skeleton is formed, achieving a perfect combination of rigidity and flexibility. This ensures sufficient structural rigidity while providing good compliance. Furthermore, the dual-segment tendon sheath drive design significantly enhances the manipulator's flexibility and workspace. Additionally, the two different tendon sheath arrangements allow users to choose between constant curvature or variable curvature bending modes according to specific application needs, providing greater adaptability. Moreover, the variable curvature bending mode enables sequential contact from proximal to distal, significantly increasing the contact area and improving gripping stability. The modular design facilitates manufacturing, assembly, and maintenance, while maintaining low cost.

Description

Technical Field

[0001] This utility model relates to the field of robotics technology, and in particular to a dual-segment tendon sheath driven rigid-flexible manipulator. Background Technology

[0002] Currently, traditional rigid-jointed robots are widely used in industrial manufacturing due to their precise control and high load capacity. However, when these robots are increasingly applied to environments outside of factories, such as unstructured environments like home services, medical rehabilitation, and agricultural harvesting, their inherent structural defects become apparent. Due to their large size, low compliance, and high driving inertia, traditional rigid robots are severely limited in adaptive operations within confined spaces. This is particularly true in grasping operations, where rigid manipulators face significant challenges. When grasping soft, fragile, irregularly shaped, or easily damaged items (such as fruits, pastries, and precision instruments), the contact between the rigid fingers and the object is typically point or line contact, leading to concentrated contact pressure. This concentrated pressure can cause discomfort, damage the surface of objects, cause scratches and discoloration of fruits and vegetables in agricultural harvesting, and potentially cause secondary injuries in medical rehabilitation. Furthermore, the plastic or paper packaging of industrial products must be handled with care to avoid damaging its shape.

[0003] To address these issues, researchers both domestically and internationally have developed various flexible manipulators. While pneumatically driven soft hands offer good compliance, they suffer from poor stiffness, poor dynamic characteristics, and expansion during actuation that reduces the actual workspace. Shape memory alloy actuations, on the other hand, are difficult to control in terms of deformation and motion precision, and their stability and time delay are challenging to manage. Regarding tendon actuations, existing designs are mainly divided into three categories: rigid tendon actuations, hybrid rigid-flexible actuations, and purely flexible actuations. Although rigid tendon-driven manipulators have mature modeling and control theories, the problem of pressure distribution on the contact surface remains unresolved. Purely flexible tendon-driven manipulators offer the best compliance, but kinematic modeling is still under development, and their stiffness and load-bearing capacity are limited. Hybrid rigid-flexible manipulators attempt to achieve a balance between compliance and stiffness, but existing designs still have certain shortcomings. For example, some only connect rigid phalanges with flexible materials, resulting in limited improvement in compliance; some employ tensioned integral structures or continuous manipulator designs, but these are structurally complex and costly to manufacture; and some, while using flexible joints, fail to achieve variable curvature bending from proximal to distal ends, leaving their grasping adaptability needing improvement. Utility Model Content

[0004] The purpose of this invention is to provide a dual-segment tendon sheath driven rigid-flexible manipulator, forming a unique hybrid structure of spring and skeleton, thus achieving a perfect combination of rigidity and flexibility. This ensures sufficient structural rigidity while providing good compliance. Furthermore, the dual-segment tendon sheath drive design greatly enhances the manipulator's flexibility and workspace. Additionally, the two different tendon sheath arrangements allow users to choose between constant curvature or variable curvature bending modes according to specific application needs, making it more adaptable. Moreover, the variable curvature bending mode enables sequential contact from proximal to distal, significantly increasing the contact area and improving gripping stability. The modular design facilitates manufacturing, assembly, and maintenance, resulting in lower costs. The compact overall structure allows operation in confined spaces, making it particularly suitable for applications in unstructured environments.

[0005] To achieve the above objectives, a dual-segment tendon sheath driven rigid-flexible manipulator is provided, comprising: Base, drive components, proximal fingers, distal fingers, and tendon sheath transmission system.

[0006] The upper surface of the base is fixedly connected to the drive component.

[0007] The proximal and distal fingers are connected in sequence to form the main body of the mechanical finger.

[0008] The proximal finger includes side-by-side proximal linear springs and multiple proximal bones connected in series on the proximal linear springs.

[0009] The distal finger includes a pair of parallel distal linear springs and multiple distal bones connected in series on the distal linear springs, and a fingertip pulley is installed at the end of the distal finger. The tendon sheath transmission system includes a proximal tendon sheath and a distal tendon sheath. The proximal tendon sheath connects the output end of the drive component to the end of the proximal finger. The distal tendon sheath passes through the proximal finger and wraps around the fingertip pulley. The distal tendon sheath is fixedly connected to the outer surface of the base or the base of the proximal finger.

[0010] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the tendon sheaths of the tendon sheath transmission system are arranged in two ways within the fingers: parallel and convergent.

[0011] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the driving component is a servo motor, the output end of the driving component is fixedly connected to a motor output pulley, and the tendon cord end of the distal tendon sheath is fixedly connected to the motor output pulley.

[0012] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the manipulator has three mechanical fingers evenly distributed in a circle on the base, and the manipulator integrates a bending sensor for real-time measurement of the bending angle of the finger segments.

[0013] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the proximal and distal bones are provided with holes or fixing structures for the proximal linear spring and the distal linear spring to pass through.

[0014] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the fingertip pulley is mounted on the distal end structure of the distal finger via a bearing.

[0015] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the distal tendon sheath is composed of an internal steel wire rope and a guide sleeve.

[0016] According to the aforementioned dual-segment tendon sheath driven rigid-flexible manipulator, the manipulator is equipped with a controller for centralized control of the drive components.

[0017] The above-mentioned solution has the following beneficial effects: 1. By setting up a unique hybrid structure of spring and skeleton, including drive components, proximal fingers, distal fingers, and tendon sheath transmission system, a perfect combination of rigidity and flexibility is achieved, ensuring sufficient structural rigidity while providing good compliance. Furthermore, the dual-segment tendon sheath drive design greatly enhances the robot's flexibility and workspace. Additionally, the two different tendon sheath arrangements allow users to choose between constant curvature or variable curvature bending modes according to specific application needs, making it more adaptable. Moreover, the variable curvature bending mode enables sequential contact from proximal to distal, significantly increasing the contact area and improving gripping stability. 2. The modular design facilitates manufacturing, assembly, and maintenance, resulting in lower costs. Its compact overall structure allows it to operate in confined spaces, making it particularly suitable for applications in unstructured environments.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 This is a schematic diagram of the overall structure of a dual-segment tendon sheath driven rigid-flexible manipulator according to the present invention. Figure 2 This is an exploded view of the structure of a single finger of a dual-segment tendon sheath driven rigid-flexible manipulator according to the present invention. Figure 3 This is a schematic diagram of two tendon sheath arrangement methods for a dual-segment tendon sheath driven rigid-flexible manipulator according to this utility model.

[0020] Legend: Among them, 1. base; 2. drive component; 3. proximal finger; 4. distal finger; 5. tendon sheath transmission system; 21. motor output pulley; 31. proximal linear spring; 32. proximal bone; 41. distal linear spring; 42. distal bone; 43. fingertip pulley; 51. proximal tendon sheath; 52. distal tendon sheath. Detailed Implementation

[0021] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0022] Reference Figures 1 to 3 This utility model discloses a dual-segment tendon sheath driven rigid-flexible manipulator, comprising: a base 1, a driving component 2, a proximal finger 3, a distal finger 4, and a tendon sheath transmission system 5. The manipulator has three mechanical fingers evenly distributed circumferentially on the base 1. The manipulator integrates a bending sensor (not shown in the figure, but a resistive flexible bending sensor can be selected, which is embedded in the back of the distal finger through silicone encapsulation or a special slot to monitor the bending state of the finger in real time) for real-time measurement of the bending angle of the finger segment. The manipulator is equipped with a controller for centralized control of the driving component 2 (not shown in the figure, responsible for coordinating the control of all driving components, and a high-performance controller based on ARM architecture can be selected).

[0023] The upper surface of the base 1 is fixedly connected to the drive component 2. The drive component 2 is set on the base 1 and is used to provide precise driving force. The drive component 2 is a servo motor. The output end of the drive component 2 is fixedly connected to the motor output pulley 21. The tendon end of the distal tendon sheath 52 is fixedly connected to the motor output pulley 21.

[0024] The proximal finger 3 and the distal finger 4 are connected in sequence to form the main body of the robotic finger. The segmented design greatly enhances the working space and flexibility of the robotic hand.

[0025] The proximal finger 3 includes a proximal linear spring 31 arranged side by side and multiple proximal bones 32 connected in series on the proximal linear spring 31. The bones provide the necessary support stiffness, precise motion guidance and reliable tendon sheath path fixation, while the linear springs give the finger good overall flexibility and adaptive deformation ability.

[0026] The distal finger 4 includes parallel distal linear springs 41 and multiple distal bones 42 connected in series on the distal linear springs 41. The bones provide the necessary support stiffness, precise motion guidance, and reliable tendon sheath path fixation, while the linear springs give the finger good overall flexibility and adaptive deformation ability. A fingertip pulley 43 is installed at the end of the distal finger 4. Holes or fixing structures are provided on the proximal bones 32 and the distal bones 42 for the proximal linear springs 31 and the distal linear springs 41 to pass through. The fingertip pulley 43 is mounted on the end structure of the distal finger 4 by bearings.

[0027] The tendon sheath transmission system 5 includes a proximal tendon sheath 51 and a distal tendon sheath 52. The proximal tendon sheath 51 connects the output end of the drive component 2 to the end of the proximal finger 3. The distal tendon sheath 52 passes through the proximal finger 3 and wraps around the fingertip pulley 43. The distal tendon sheath 52 is fixedly connected to the outer surface of the base 1 or the base of the proximal finger 3, changing the transmission path of the tendon rope, reducing friction loss, and improving transmission efficiency. The tendon sheaths of the tendon sheath transmission system 5 are arranged in two ways inside the finger: parallel and convergent. The parallel arrangement makes the finger present an arc shape with an approximately constant curvature when subjected to force. The kinematic model is relatively simple and easy to control, which is suitable for application scenarios that require precise trajectory tracking. The convergent arrangement makes the driving torque at the proximal end greater than that at the distal end when the finger bends, thus naturally forming a variable curvature shape with decreasing curvature from the proximal end to the distal end. The distal tendon sheath 52 is composed of an internal steel wire rope and a guide sleeve.

[0028] Those skilled in the art should connect all electrical components in this case to their compatible external power supply via wires, and should select a suitable controller according to the actual situation to meet the control requirements. The specific connection and control sequence should refer to the working principle described below, where the electrical components are connected in sequence. The detailed connection methods are well-known in the art. The following mainly introduces the working principle and process, and will not describe the electrical control further.

[0029] Working principle: When the tendon sheath is arranged in parallel within the finger, the proximal bones 32 are first sequentially connected to the proximal linear springs 31 to form the flexible trunk of the proximal finger 3. Using the same method, the distal bones 42 are connected to the distal linear springs 41 to form the trunk of the distal finger 4. The fingertip pulleys 43 are then installed. The assembled proximal finger 3 and distal finger 4 are then connected via a specially designed segmental disc with pre-drilled holes for the tendon sheath. At this point, under the action of the parallel arrangement, the distal tendon sheath 52... The steel wire rope originates from the motor output pulley 21, ensuring its path remains parallel to the finger axis. It precisely passes through the guide holes on the proximal finger 3 and distal finger 4, smoothly wraps around the fingertip pulley 43, and then returns and is securely fixed to the base of the proximal finger 3. With this structure, when the distal tendon sheath 52 is tightened, the entire distal finger 4 will bend uniformly into an arc with an approximately constant curvature. This shape is particularly suitable for applications requiring precise trajectory control. Furthermore, when the tendon sheath is arranged in a converging pattern within the finger, the initial assembly steps are similar to those in a parallel arrangement. Similarly, in the design of the tendon sheath path, a specially designed oblique threading hole is made on the segment plate of the finger base, so that the entry point of the distal tendon sheath 52 is located on the periphery of the finger cross section. The travel path of the steel wire rope inside the finger is precisely calculated, gradually converging from the periphery to the center line, and finally passing around the fingertip pulley 43 before being fixed. This convergence path design produces unique mechanical characteristics. When the distal tendon sheath 52 is tightened, due to the long lever arm at the proximal end, a large bending moment is generated at the root, and the degree of bending is obvious. As it gets closer to the fingertip, the lever arm gradually shortens, and the degree of bending decreases accordingly, thus naturally forming a beautiful curve with the curvature gradually decreasing from the root to the fingertip. This bending shape is more biomimetic and can better adapt to objects of various complex shapes, achieving stable and reliable grasping. Finally, the three assembled fingers are precisely installed on the base 1 at 120-degree equal angles, all motors and sensors are connected to the controller, and a streamlined shell is installed to protect the internal mechanism. The entire robotic arm's circuit system adopts a modular design, which facilitates maintenance and troubleshooting.

[0030] In the description of this utility model, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," and "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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. At the same time, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "fixed installation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two elements or the interaction relationship between two elements. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A dual-segment tendon sheath driven rigid-flexible manipulator, characterized in that, include: Base (1), drive unit (2), proximal finger (3), distal finger (4) and tendon sheath transmission system (5); The upper surface of the base (1) is fixedly connected to the driving component (2); The proximal finger (3) and distal finger (4) are connected in sequence to form the main body of the mechanical finger; the proximal finger (3) includes a proximal linear spring (31) arranged side by side and multiple proximal bones (32) connected in series on the proximal linear spring (31). The distal finger (4) includes a pair of distal linear springs (41) arranged side by side and a plurality of distal bones (42) connected in series on the distal linear springs (41). The distal finger (4) is equipped with a fingertip pulley (43). The tendon sheath transmission system (5) includes a proximal tendon sheath (51) and a distal tendon sheath (52). The proximal tendon sheath (51) connects the output end of the drive component (2) to the end of the proximal finger (3). The distal tendon sheath (52) passes through the proximal finger (3) and passes around the fingertip pulley (43). The distal tendon sheath (52) is fixedly connected to the base (1) or the outer surface of the base of the proximal finger (3).

2. The dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The tendon sheaths of the tendon sheath transmission system (5) are arranged in two ways inside the finger: parallel and convergent.

3. The dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The driving component (2) is a servo motor, and the output end of the driving component (2) is fixedly connected to a motor output pulley (21). The tendon end of the distal tendon sheath (52) is fixedly connected to the motor output pulley (21).

4. The dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The robotic hand has three robotic fingers that are evenly distributed in a circle on the base (1). The robotic hand integrates a bending sensor for real-time measurement of the bending angle of the finger segments.

5. A dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The proximal bone (32) and distal bone (42) are provided with holes or fixing structures for the proximal linear spring (31) and distal linear spring (41) to pass through.

6. A dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The fingertip pulley (43) is mounted on the distal end structure of the distal finger (4) via a bearing.

7. A dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The distal tendon sheath (52) consists of an internal steel wire rope and a guide sleeve.

8. A dual-segment tendon sheath driven rigid-flexible manipulator according to claim 1, characterized in that, The robotic arm is equipped with a controller for centralized control of the drive component (2).

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