Novel rigid-flexible coupling robot and working method thereof

Abstract

The application relates to a novel rigid-flexible coupling mechanical hand and a working method thereof, which comprises a base and a plurality of bendable finger structures arranged above the base, each finger structure comprising a top joint, a middle joint and a bottom joint arranged in sequence from top to bottom, wherein the top joint and the middle joint and the middle joint and the bottom joint are connected through elastic element groups, and a variable stiffness assembly is arranged in the middle joint and connected with the top joint and the bottom joint respectively. The application has the advantages of simple structure, reasonable design, good compliance, good compactness, safety and economy, small size and convenience, and the like.

Description

Technical Field

[0001] This invention relates to a novel rigid-flexible coupling manipulator and its working method. Background Technology

[0002] A robotic arm is an automated device that can mimic certain movements and functions of a human hand and arm to grasp, move objects, or operate tools according to a fixed program. Robotic arms can replace heavy human labor to achieve mechanization and automation of production, and can operate in hazardous environments to protect human safety; therefore, they are widely used in many fields.

[0003] Most existing rigid robotic hands use tendon drives, which are generally driven by motors. They require high positional control precision and have poor adaptability. If the control precision is insufficient, it can cause significant damage to the object being grasped. Therefore, rigid joints cannot fully utilize the characteristics of flexible deformation. On the other hand, most existing flexible robotic hands are pneumatically driven, with cylinders and air pumps. They are bulky, inconvenient to carry, and prone to air leakage. Although they can adapt to various unstructured environments, their load-bearing capacity is poor due to the properties of the materials, and the control precision is difficult to guarantee. At the same time, the fingers of robotic hands often need to be made of multiple materials to achieve unilateral bending capability through different bending strengths, which is inconvenient to manufacture. While soft robots, which are mainly made of soft materials, complement rigid robots to some extent, their stiffness problem has not yet been solved. Summary of the Invention

[0004] The present invention addresses the above-mentioned problems by providing a novel rigid-flexible coupling manipulator and its working method.

[0005] The present invention is configured as follows: it includes a base and a plurality of flexible finger structures disposed above the base. Each finger structure includes a top joint, a middle joint and a bottom joint arranged sequentially from top to bottom. The top joint and the middle joint, and the middle joint and the bottom joint are connected by an elastic element group. A variable stiffness component is disposed in the middle joint, and the variable stiffness component is connected to the top joint and the bottom joint respectively.

[0006] Furthermore, the elastic element group includes at least two vertical tension springs and at least two groups of laterally arranged saddle tension springs, each group of saddle tension springs including at least two laterally arranged saddle tension springs.

[0007] Furthermore, the variable stiffness assembly includes a rotatable cable reel located inside the middle joint and variable stiffness springs located above and below the cable reel. The upper end of the upper variable stiffness spring is connected to the lower middle part of the top joint, and the lower end of the upper variable stiffness spring is connected to the cable reel via an upper fixing rope. The upper end of the lower variable stiffness spring is connected to the cable reel via a lower fixing rope, and the lower end of the lower variable stiffness spring is connected to the upper middle part of the bottom joint.

[0008] Furthermore, the winding box is driven to rotate by a motor located outside the central joint.

[0009] Furthermore, the finger structure is driven to bend by a finger drive device located below the base.

[0010] Furthermore, the finger drive device includes a servo swing arm and a servo motor for driving the height of the two sides of the servo swing arm to change. Drive ropes are provided on both sides below the top joint. The drive ropes on both sides pass through the lower part of the top joint, the middle joint, and the bottom joint in sequence and are respectively connected to the two sides of the servo swing arm.

[0011] Furthermore, the included angle between two adjacent saddle tension springs in the same group is 40°.

[0012] Furthermore, a novel rigid-flexible coupling manipulator operates by using a servo motor to change the position of the drive ropes on both sides of each finger structure, thereby controlling the bending of the finger structure and completing the grasping task.

[0013] Furthermore, by controlling the motor to drive the winding reel to rotate, the preload of the variable stiffness spring can be adjusted by tightening or loosening the upper and lower fixed ropes, thereby changing the stiffness of the finger structure.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The manipulator is formed by a top joint, a middle joint, and a bottom joint to form a rigid compression element, and by an elastic element and a variable stiffness component to form an elastic tension element. There is no contact between the rigid compression elements, resulting in low friction. (2) The two variable stiffness springs and the motor of the variable stiffness component form a tension joint. The transmission of motion, energy and force is achieved through the elastic deformation of the variable stiffness spring. It has significant advantages of being lightweight, modular and highly scalable. As a low-friction flexible joint, the tension joint has good environmental adaptability. (3) The servo motor is a position servo drive, which is particularly suitable for control systems that need to change angles and maintain them. With the improvement of electronic integration, the servo motor is becoming smaller and lighter, while being easy to control and having good stability. (4) The finger structure of the manipulator is modular, which facilitates disassembly and replacement of parts. (5) This device has a simple structure and reasonable design. The position of the drive rope on both sides of each finger structure is changed by the servo motor, thereby controlling the bending of the finger structure and completing the grasping work. During the operation, the motor drives the winding reel to rotate, and the state of the variable stiffness spring is controlled by the upper and lower fixed ropes. The stiffness of the finger structure is adjusted by adjusting the preload. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the finger structure in an embodiment of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the finger structure in an embodiment of the present invention. Figure 2 ; Figure 4 for Figure 2 A magnified view of a portion of the image; Figure 5 for Figure 3 Enlarged view of part B; Figure 6 A cross-sectional view of the finger structure according to an embodiment of the present invention. Figure 1 ; Figure 7 A cross-sectional view of the finger structure according to an embodiment of the present invention. Figure 2 ; Figure 8 This is a simplified schematic diagram illustrating the working state of the finger driving device according to an embodiment of the present invention; In the diagram: 1-base, 2-finger structure, 21-top joint, 22-middle joint, 23-bottom joint, 24-fixed plate, 3-elastic element group, 31-vertical tension spring, 32-saddle tension spring, 4-variable stiffness assembly, 41-coil reel, 42-variable stiffness tension spring, 43-upper fixed rope, 44-lower fixed rope, 45-motor, 5-finger drive device, 51-servo yaw arm, 52-servo, 53-drive rope, 54-guide hole, 55-joint. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0017] Example: Refer to Appendix Figure 1-8 As shown, a novel rigid-flexible coupling manipulator is provided, including a base 1 and three flexible finger structures 2 evenly arranged on the upper part of the base along the circumference of the base. Each finger structure includes a top joint 21, a middle joint 22 and a bottom joint 23 arranged sequentially from top to bottom. The top joint and the middle joint, and the middle joint and the bottom joint are connected by an elastic element group 3. A variable stiffness component 4 is provided in the middle joint, which is connected to the top joint and the bottom joint respectively.

[0018] The top, middle, and bottom joints mentioned above are rigid; the variable stiffness tension joints of the robot are constructed by two variable stiffness springs of the variable stiffness component. At the same time, they will also serve as the tension unit in the overall tension structure, together with the aforementioned six tension springs (two vertical tension springs and four saddle tension springs) to form a tension network.

[0019] In this embodiment of the invention, the elastic element group 3 includes two vertical tension springs 31 and two symmetrically arranged saddle tension spring groups, each saddle tension spring group including two transversely arranged saddle tension springs 32.

[0020] The lower part of the aforementioned top joint is fitted onto the outer side of the top of the middle joint. Fixing plates 24 are provided at the front and rear of the top of the middle joint. Two saddle tension springs 32 are provided between each fixing plate and the bottom of the middle joint. The lower part of the aforementioned middle joint is fitted onto the outer side of the top of the bottom joint. Fixing plates 24 are also provided at the front and rear of the top of the bottom joint. Two saddle tension springs are provided between each fixing plate and the bottom of the middle joint. The included angle between two adjacent saddle tension springs in the same group is 40°.

[0021] A vertical tension spring 31 is provided at the front and back of the top joint and the middle joint, and at the middle joint and the bottom joint.

[0022] In this embodiment of the invention, the variable stiffness component 4 includes a rotatable winding box 41 disposed inside the middle joint and variable stiffness springs 42 located above and below the winding box. The upper end of the upper variable stiffness spring is connected to the lower middle part of the top joint, the lower end of the upper variable stiffness spring is connected to the winding box via an upper fixing rope 43, the upper end of the lower variable stiffness spring is connected to the winding box via a lower fixing rope 44, and the lower end of the lower variable stiffness spring is connected to the upper middle part of the bottom joint.

[0023] The variable stiffness tension spring located at the top is situated between the two sets of saddle tension springs.

[0024] The aforementioned winding box is driven to rotate by a motor 45 located outside the central joint. The motor drives the winding reel to rotate, and the variable stiffness is achieved by controlling the tension of the upper and lower fixed ropes connected to the variable stiffness spring.

[0025] In this embodiment of the invention, the finger structure is driven to bend by a finger driving device disposed below the base.

[0026] The finger drive device 5 includes a servo swing arm 51 and a servo motor 52 for driving the height of the two sides of the servo swing arm to change. Drive ropes 53 are fixed on both sides below the top joint. The drive ropes on both sides pass through the lower part of the top joint, the middle joint and the bottom joint in sequence and are connected to the two sides of the servo swing arm respectively.

[0027] The top joint, middle joint and bottom joint mentioned above are all provided with guide holes 54 on both sides for driving the rope to pass through.

[0028] When the finger-driven device is working: the microcontroller controls the swing of the servo motor, which pulls the drive rope through the servo motor's swing arm, transmitting the driving torque of the servo motor. When the servo motor swing arm rotates at a certain angle, the two sides of the servo motor swing arm move in opposite directions by a distance of ∆ML, thereby causing a change in the length of the corresponding drive rope, which in turn causes each joint to bend at 55 degrees. The length of the drive rope connected to the upper end of the servo motor arm will increase, while the length of the drive rope on the other side will decrease by ∆ML. This is the principle of the expansion and contraction of the drive rope on both sides when the servo motor is working.

[0029] In this embodiment of the invention, the manipulator is a rigid-flexible coupling manipulator based on a tensioned integral structure. The top, middle, and bottom joints of the manipulator are three rigid components that do not contact each other, resulting in low friction between the components. Combined with two vertical tension springs and four saddle springs in each set of elastic elements, the variable stiffness springs of the variable stiffness component form a tension network. The rigid components achieve self-balancing within this tension network. As a combination of rigid and flexible materials, the stiffness of the tensioned integral structure can be adjusted by the preload, i.e., by driving the winding reel with a motor to change the variable stiffness springs, thereby adjusting the preload. The tensioned joints, as low-friction flexible joints, offer advantages such as lightweight, modularity, and high scalability. As low-friction flexible joints, the tensioned joints also exhibit good environmental adaptability. Furthermore, this manipulator possesses excellent characteristics such as good quality, high symmetry, good compliance, sufficient toughness, and excellent topological properties. Its high symmetry allows for easy connection of unit units to form a modular robot.

[0030] In this embodiment of the invention, during operation: the position of the drive ropes on both sides of each finger structure is changed by the servo motor, thereby controlling the bending of the finger structure to complete the grasping work; during operation, the motor drives the winding reel to rotate, and the state of the variable stiffness spring is controlled by the upper and lower fixed ropes, and the stiffness of the finger structure is adjusted by adjusting the preload.

[0031] Unless otherwise stated, if any technical solution disclosed in this invention discloses a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely a range of numerical values ​​among many implementable values ​​that have a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0032] If the terms "first" or "second" are used in this document to specify components, those skilled in the art should know that the use of "first" or "second" is merely for the purpose of distinguishing components in description, and unless otherwise stated, the above terms have no special meaning.

[0033] Meanwhile, if the present invention discloses or relates to mutually fixedly connected parts or structural components, then unless otherwise stated, fixed connection can be understood as: a fixed connection that can be detached (e.g., using bolts or screws), or a fixed connection that cannot be detached (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured by integral molding using a casting process) (except where it is obviously impossible to use an integral molding process).

[0034] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0035] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A novel rigid-flexible coupling manipulator, characterized in that, It includes a base and multiple bendable finger structures disposed above the base. Each finger structure includes a top joint, a middle joint and a bottom joint arranged sequentially from top to bottom. The top joint and the middle joint, as well as the middle joint and the bottom joint, are connected by an elastic element group. A variable stiffness component is disposed inside the middle joint, and the variable stiffness component is connected to the top joint and the bottom joint respectively. The top joint, middle joint, and bottom joint mentioned above are all provided with guide holes on both sides for threading the drive rope. The elastic element group includes at least two vertical tension springs and at least two groups of laterally arranged saddle tension springs, each group of saddle tension springs including at least two laterally arranged saddle tension springs; The included angle between two adjacent saddle tension springs in the same group is 40°; The finger drive device includes a servo swing arm and a servo motor for driving the height of the two sides of the servo swing arm to change. Drive ropes are provided on both sides below the top joint. The drive ropes on both sides pass through the lower part of the top joint, the middle joint, and the bottom joint in sequence and are connected to the two sides of the servo swing arm respectively.

2. The novel rigid-flexible coupling manipulator according to claim 1, characterized in that, The variable stiffness assembly includes a rotatable cable reel located inside the middle joint and variable stiffness springs located above and below the cable reel. The upper end of the upper variable stiffness spring is connected to the lower middle part of the top joint, and the lower end of the upper variable stiffness spring is connected to the cable reel via an upper fixing rope. The upper end of the lower variable stiffness spring is connected to the cable reel via a lower fixing rope, and the lower end of the lower variable stiffness spring is connected to the upper middle part of the bottom joint.

3. The novel rigid-flexible coupling manipulator according to claim 2, characterized in that, The winding box is driven to rotate by a motor located outside the central joint.

4. The novel rigid-flexible coupling manipulator according to claim 3, characterized in that, The finger structure is driven to bend by a finger drive device located below the base.

5. A working method for a novel rigid-flexible coupling manipulator as described in claim 4, characterized in that, By changing the position of the drive ropes on both sides of each finger structure through a servo motor, the bending of the finger structure is controlled to complete the grasping task.

6. The working method of the novel rigid-flexible coupling manipulator according to claim 5, characterized in that, By controlling the motor to drive the winding reel to rotate, the preload of the variable stiffness spring can be adjusted by winding up or loosening the upper and lower fixed ropes, thereby changing the stiffness of the finger structure.

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