A flexible arm with variable stiffness

Abstract

The present invention discloses a flexible arm with variable stiffness, comprising an annular outer enclosure and a conducting wire, flexible arm ends are respectively arranged at both ends of the annular outer enclosure, the annular outer enclosure is made of a flexible material, the annular outer enclosure and the flexible arm ends are enclosed together to form a filling space, and the conducting wire passes through the filling space; a pull rope assembly is arranged between the flexible arm ends at both ends, and the pull rope assembly is used to limit the distance between the flexible arm ends at both ends; the filling space is filled with particles, and a trachea joint is arranged on one of the flexible arm ends; the vacuum degree in the filling space is adjusted by the trachea joint to change the extrusion force between the plate particles, thereby adjusting the stiffness of the flexible arm. The present invention can effectively adjust the overall stiffness of the flexible arm by adjusting the vacuum degree in the filling space, and realize the stepless adjustment of the stiffness of the flexible arm, so as to meet the stiffness requirements of the flexible arm in various different scenarios, and improve its applicability in multiple fields.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical arms, and in particular to a flexible arm with variable stiffness. Background Art

[0002] In the current field of robotics, especially in industrial robots and service robots, rigid metal materials are widely used as the main structure of robotic arms. These robotic arms usually rely on powerful motor drives and precise joint control systems to perform complex movements. In industrial scenarios, rigid robotic arms are mostly used for handling, assembly, welding and other tasks, with high rigidity, high precision and durability. However, the rigidity of this type of robotic arm is determined by its material itself, and its own flexibility cannot be adjusted. In order to cope with diverse work requirements, some robotic arms have added force sensors at the joints or used complex control systems to achieve flexible operation, but the overall structure is still mainly rigid.

[0003] In human-machine collaboration scenarios such as medical and household robots, some flexible robotic arms are gradually being introduced, especially in rehabilitation robots and assistive devices. These flexible robotic arms usually use soft materials or pneumatic systems to achieve safe contact and flexible operation. However, the main problem with flexible robotic arms is that it is difficult to provide sufficient support and rigidity when needed, which limits their application scope.

[0004] Although existing rigid robotic arms have achieved great success in the fields of industry and automation, they still have obvious safety hazards and limitations. If a traditional rigid robotic arm accidentally collides with the human body or other objects during work, it may cause serious injuries. In addition, robotic arms made of rigid materials cannot adjust their stiffness according to task requirements, resulting in poor performance in certain scenarios that require flexible operations, such as medical surgery or human-machine collaboration. In addition, although existing flexible robotic arms have certain advantages in safety, they cannot provide sufficient structural support and cannot function effectively in application scenarios that require high stiffness.

[0005] Therefore, existing robotic arms lack effective adjustment capabilities between flexibility and rigidity and cannot meet the requirements of both high safety and high support force at the same time, which restricts their application in many fields. Summary of the invention

[0006] The object of the present invention is to solve the deficiencies in the prior art and provide a flexible arm with variable stiffness.

[0007] The objective of the present invention is achieved through the following technical solutions: a flexible arm with variable stiffness, comprising an annular outer enclosure and a conductor, wherein the annular outer enclosure is made of a flexible material, and flexible arm ends are respectively arranged at both ends of the annular outer enclosure, and the annular outer enclosure and the flexible arm ends are jointly enclosed to form a filling space, and the conductor passes through the filling space; a pull rope assembly is arranged between the flexible arm ends at both ends, and the pull rope assembly is used to limit the distance between the flexible arm ends at both ends;

[0008] The filling space is filled with particles, and an air pipe joint is arranged on the end of one of the flexible arms; the vacuum degree in the filling space is adjusted through the air pipe joint to change the squeezing force between the plate particles, thereby adjusting the rigidity of the flexible arm.

[0009] Preferably, the particles are ABS resin particles, the particles are spherical, and the diameter of the particles is 1-3 mm.

[0010] Preferably, the annular outer enclosure is an annular airbag; the annular airbag comprises an inner annular airbag layer and an outer annular airbag layer, the inner side of the inner annular airbag layer is provided with an annular connector corresponding to the end of the flexible arm; the annular connector is sealingly connected to the end of the flexible arm.

[0011] Preferably, an inner buckle ring and an outer buckle ring are provided on the end of the flexible arm, and the inner buckle ring and the outer buckle ring clamp the annular connector.

[0012] Preferably, the inner buckle ring is made of polyurethane.

[0013] Preferably, welding pins are respectively provided at both ends of the wire, the welding pins pass through the ends of the flexible arms, and an insulating sheath is provided between the welding pins and the ends of the flexible arms.

[0014] Preferably, the pull rope assembly includes a hollow rope and a glue filling head connected to both ends of the hollow rope, the glue filling head is provided with a glue filling hole, the end of the hollow rope extends into the glue filling hole on the glue filling head, the glue filling hole is filled with glue to achieve the connection between the hollow rope and the glue filling head; the hollow rope is filled with particles; the glue filling head is connected to the end of the flexible arm.

[0015] Preferably, a connecting piece is provided on the end of the flexible arm, and the connecting piece is connected to the end of the flexible arm by a screw; the connecting piece is provided with an external thread, and the glue filling head is provided with an internal thread matching the external thread, and the glue filling head and the connecting piece are threadedly matched.

[0016] Preferably, the air pipe joint is connected to the vacuum pump via an air guide tube.

[0017] Preferably, the annular airbag is spindle-shaped after being inflated.

[0018] The beneficial effects of the present invention are:

[0019] 1. The present invention can effectively adjust the overall stiffness of the flexible arm by adjusting the vacuum degree in the filling space, and realize stepless adjustment of the stiffness of the flexible arm, thereby being able to meet the stiffness requirements of the flexible arm in various scenarios and improving its applicability in multiple fields.

[0020] 2. When the stiffness of the flexible arm is adjusted in the present invention, it is only necessary to change the vacuum degree in the filling space, and the control method is relatively simple; and when the vacuum degree in the filling space changes, the stiffness of the flexible arm will also change rapidly, and the response speed is fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the structure of the present invention after the annular airbag is removed.

[0023] Figure 3 It is a cross-sectional view of the present invention.

[0024] Figure 4 It is a structural schematic diagram of the flexible arm end.

[0025] Figure 5 It is a schematic diagram of the structure of the pull rope assembly.

[0026] Figure 6 A cross-sectional view of the pull cord assembly.

[0027] Figure 7 Schematic diagram of the structure of the annular airbag.

[0028] In the figure: 1. annular airbag, 2. flexible arm end, 3. inner buckle ring, 4. welding pin, 5. insulating sheath, 6. trachea joint, 7. plug, 8. sealant, 9. outer buckle ring, 10. wire, 11. filling space, 12. hollow rope, 13. glue filling head, 14. joint through hole, 15. welding pin through hole, 16. threaded hole, 17. connector, 18. screw, 19. glue filling hole, 20. annular connector. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0030] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "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 drawings, which are only for the convenience of describing 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. Therefore, the above terms should not be understood as limiting the present invention.

[0031] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0032] like Figures 1 to 7 As shown, a flexible arm with variable stiffness includes an annular outer enclosure and a conductive wire 10. Flexible arm ends 2 are respectively provided at both ends of the annular outer enclosure, and the annular outer enclosure is made of a flexible material. The annular outer enclosure and the flexible arm end 2 together enclose a filling space 11, and the conductive wire 10 passes through the filling space 11; a pull rope assembly is provided between the flexible arm ends 2 at both ends, and the pull rope assembly is used to limit the distance between the flexible arm ends 2 at both ends; the filling space 11 is filled with granular bodies, and an air pipe joint 6 is provided on one of the flexible arm ends 2; the vacuum degree in the filling space 11 is adjusted by the air pipe joint 6 to change the extrusion force between the plate granular bodies, thereby adjusting the stiffness of the flexible arm.

[0033] In the present invention, the filling space 11 is a closed space, and the trachea joint 6 is connected with a trachea, which is connected to an external vacuum adjustment device, and the vacuum adjustment device (such as a vacuum pump, etc.) is used to adjust the vacuum in the filling space 11. When the filling space 11 is at a high vacuum, the annular outer inclusion tightly wraps the granules in the filling space 11 under the action of the internal negative pressure, so that the granules in the filling space 11 form a hard whole under tight squeezing, and it is difficult for the granules to move relative to each other. At this time, the flexible arm shows a higher rigidity and higher support; when the vacuum in the filling space 11 decreases, the tightness of the annular outer inclusion wrapping the granules decreases, so that the squeezing tightness between the granules decreases, and the fluidity between the granules is improved, thereby reducing the rigidity of the flexible arm and increasing the flexibility; by adjusting the vacuum in the filling space 11, the overall rigidity of the flexible arm can be effectively adjusted, and the stepless adjustment of the rigidity of the flexible arm can be achieved, so that the rigidity requirements of the flexible arm in various different scenarios can be met, and its applicability in multiple fields is improved. Moreover, when the present invention adjusts the stiffness of the flexible arm, it is only necessary to change the vacuum degree in the filling space 11, and the control method is relatively simple; and when the vacuum degree in the filling space 11 changes, the stiffness of the flexible arm will also change rapidly, and the response speed is fast; in this way, when encountering an emergency situation, such as when the flexible arm collides with other people or objects and needs to quickly switch to a flexible state and avoid it, the flexible arm can quickly adjust its stiffness to cope with the emergency.

[0034] In this embodiment, the particles are ABS resin particles, the particles are spherical, and the diameter of the particles is 1-3 mm.

[0035] In order to install the trachea connector 6 on the flexible arm end 2, a connector through hole 14 is provided on the flexible arm end 2. The trachea connector 6 is installed in the connector through hole 14 on one of the flexible arm ends 2, while a plug 7 is installed in the connector through hole 14 on the other flexible arm end 2, and the connector through hole 14 is closed by the plug 7.

[0036] Specifically, the annular outer wrapping body is an annular airbag 1; the annular airbag 1 includes an inner annular airbag layer and an outer annular airbag layer, and the inner side of the inner annular airbag layer is provided with an annular connector 20 corresponding to the flexible arm end 2; the annular connector 20 is sealed and connected to the flexible arm end 2.

[0037] After the annular airbag 1 is inflated, it swells up, making the outer side of the flexible arm flexible. The advantages are: 1. When the flexible arm collides with an external object or person, the annular airbag 1 can play a good buffering role, reduce the impact on the flexible arm, and avoid damage to the flexible arm; and the existence of the annular airbag 1 can also reduce the damage caused by the collision to external objects or people. 2. The inner and outer double-layer structure of the annular airbag 1 can effectively prevent the impact of scratches and punctures of external sharp objects on the airtightness of the internal filling space 11; but when the outer side of the flexible arm touches a sharp object, even if the sharp object scratches the outer annular airbag layer of the annular airbag 1, it is difficult to damage the inner annular airbag layer of the annular airbag 1. The existence of the inner annular airbag layer can still ensure the sealing of the filling space 11, thereby ensuring the normal operation of the flexible arm.

[0038] In this embodiment, the annular airbag 1 is spindle-shaped after being inflated.

[0039] The flexible arm end 2 is provided with an inner buckle ring 3 and an outer buckle ring 9, which clamp the annular connector 20. The annular connector 20 is a ring of flexible material arranged on the inner side of the inner annular airbag layer, and the material of the annular connector 20 is the same as that of the annular airbag 1; the inner buckle ring 3 is tightly sleeved on the flexible arm end 2, and the outer buckle ring 9 is located on the outer side of the inner buckle ring 3, and an annular gap is formed between the inner buckle ring 3 and the outer buckle ring 9. The annular connector 20 extends into the annular gap between the inner buckle ring 3 and the outer buckle ring 9 and is clamped by the inner buckle ring 3 and the outer buckle ring 9, thereby realizing a sealed connection between the annular airbag 1 and the flexible arm end 2, and air leakage occurs at the connection between the flexible arm end 2 and the annular airbag 1.

[0040] In this embodiment, the inner buckle ring 3 is made of polyurethane and has a certain elasticity. The inner buckle ring 3 is sleeved on the flexible arm end 2 and has an interference fit with the flexible arm end 2. The elasticity of the inner buckle ring 3 itself can tightly clamp the annular connector 20.

[0041] A welding pin 4 is provided at each end of the wire 10. The welding pin 4 passes through the flexible arm end 2. An insulating sheath 5 is provided between the welding pin 4 and the flexible arm end 2. The flexible arm end 2 is provided with a welding pin through hole 15 through which the welding pin 4 can pass. The insulating sheath 5 is arranged in the welding pin through hole 15. The insulating sheath 5 isolates the welding pin 4 from the flexible arm end 2, thereby maintaining insulation between the two. A sealant 8 is poured into the welding pin through hole 15 to ensure the airtightness of the filling space 11.

[0042] Specifically, the pull rope assembly includes a hollow rope 12 and a glue filling head 13 connected to both ends of the hollow rope 12. The glue filling head 13 is provided with a glue filling hole 19. The end of the hollow rope 12 extends into the glue filling hole 19 on the glue filling head 13. The glue filling hole 19 is filled with glue to achieve the connection between the hollow rope 12 and the glue filling head 13; the hollow rope 12 is filled with particles; the glue filling head 13 is connected to the end 2 of the flexible arm.

[0043] The hollow rope 12 is air permeable, and the vacuum degree of the hollow area in the hollow rope 12 is consistent with the vacuum degree in the filling space 11. This makes the state of the particles in the filling space 11 consistent with that of the particles in the hollow rope 12, that is, when the particles in the filling space 11 are in a rigid state, the particles in the hollow rope 12 are also in the same rigid state. In this embodiment, the material of the hollow rope 12 is aramid.

[0044] Furthermore, a connector 17 is provided on the flexible arm end 2, and the connector 17 is connected to the flexible arm end 2 by a screw 18; an external thread is provided on the connector 17, and an internal thread matching the external thread is provided on the glue filling head 13, and the glue filling head 13 and the connector 17 are threadedly matched. The connector 17 is an annular structure, and the external thread is provided on the outer ring surface of the connector 17; a threaded hole 16 matching the screw 18 is provided on the flexible arm end 2, and the screw 18 passes through the connector 17 and is connected to the threaded hole 16 on the flexible arm end 2, so that the connector 17 is fixed on the flexible arm end 2; the internal thread is provided on the inner side of the glue filling hole on the glue filling head 13, and the glue filling head 13 is fixedly connected with the connector 17 by threaded connection.

[0045] The air pipe joint 6 is connected to a vacuum pump via an air guide tube. The vacuum degree in the filling space 11 is controlled by the vacuum pump.

[0046] Furthermore, a pressure sensor is installed in the annular airbag 1, and the pressure sensor can be attached to the inner side of the annular airbag 1. The pressure sensor is connected to the control system, and the pressure sensor can transmit the air pressure value in the annular airbag 1 to the control system in real time. Through the pressure sensor, the annular airbag 1 can be accurately inflated to the required pressure state. At the same time, the pressure sensor can be used to determine whether the flexible arm collides with an external object or person. The principle is as follows: when an external object or person collides with the annular airbag 1 on the flexible arm, the annular airbag 1 will be squeezed due to the collision. At this time, the pressure inside the annular airbag 1 will instantly rise to a certain value, and an obvious peak will be generated on the pressure curve. During the conventional bending operation of the flexible arm, the pressure change inside the annular airbag 1 is very small, and the pressure change rate is relatively slow, which is different from the situation where the annular airbag 1 is collided. Therefore, it is only necessary to detect the pressure change of the annular airbag 1 to determine whether the flexible arm has collided with other objects or people. When it is detected that the flexible arm collides with an external object or person, the damage to the collided object or person can be reduced by increasing the flexibility of the flexible arm (i.e., reducing the stiffness of the flexible arm).

[0047] The specific method is as follows: the gas pressure in the annular airbag 1 is detected in real time by a pressure sensor. When the pressure increase value of the gas pressure within a set time interval exceeds a threshold, it is judged that the flexible arm has collided with the surrounding objects or people. At this time, the control system immediately controls the vacuum adjustment device to start and immediately reduce the vacuum degree in the filling space 11 to the set value (that is, increase the pressure in the filling space 11), thereby quickly reducing the stiffness of the flexible arm to avoid people or objects and reduce the impact on people or objects. In this way, the flexible arm can respond immediately after the collision occurs, thereby improving the effectiveness of the avoidance operation.

[0048] The time interval and the threshold can be set in advance. The time interval can be 0.1 seconds.

[0049] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A flexible arm with variable stiffness, characterized in that: It includes an annular outer enclosure and a conductor. Flexible arm ends are respectively arranged at both ends of the annular outer enclosure. The annular outer enclosure is made of a flexible material. The annular outer enclosure and the flexible arm ends together enclose a filling space, and the conductor passes through the filling space. A pull rope assembly is arranged between the flexible arm ends at both ends, and the pull rope assembly is used to limit the distance between the flexible arm ends at both ends. The filling space is filled with particles, and an air pipe joint is provided on the end of one of the flexible arms; the vacuum degree in the filling space is adjusted through the air pipe joint to change the squeezing force between the particles, thereby adjusting the rigidity of the flexible arm; The particle body is ABS resin particle, and the particle body is spherical; the annular outer inclusion is an annular airbag; the annular airbag includes an inner annular airbag layer and an outer annular airbag layer, and the inner side of the inner annular airbag layer is provided with an annular connector corresponding to the end of the flexible arm; the annular connector is sealed and connected to the end of the flexible arm; A pressure sensor is installed in the annular airbag, and the gas pressure in the annular airbag is detected in real time by the pressure sensor. When the pressure increase value of the gas pressure within a set time interval exceeds a threshold, it is judged that the flexible arm has collided with the surrounding objects or people. At this time, the control system immediately controls the vacuum degree adjustment device to start and immediately reduce the vacuum degree in the filling space to the set value, thereby reducing the rigidity of the flexible arm; The pull rope assembly includes a hollow rope and a glue filling head connected to both ends of the hollow rope, wherein the glue filling head is provided with a glue filling hole, and the end of the hollow rope extends into the glue filling hole on the glue filling head, and the glue filling hole is filled with glue to achieve the connection between the hollow rope and the glue filling head; the hollow rope is filled with particles; the glue filling head is connected to the end of the flexible arm; the hollow rope is air permeable, and the vacuum degree of the hollow area in the hollow rope is consistent with the vacuum degree in the filling space, so that the state of the particles in the filling space is consistent with that of the particles in the hollow rope.

2. A flexible arm with variable stiffness according to claim 1, characterized in that: The diameter of the granules is 1-3 mm.

3. A flexible arm with variable stiffness according to claim 1, characterized in that: An inner buckle ring and an outer buckle ring are arranged on the end of the flexible arm, and the inner buckle ring and the outer buckle ring clamp the annular connector.

4. A flexible arm with variable stiffness according to claim 3, characterized in that: The inner buckle ring is made of polyurethane.

5. A flexible arm with variable stiffness according to claim 1, characterized in that: The two ends of the wire are respectively provided with welding pins, the welding pins pass through the ends of the flexible arms, and an insulating sheath is provided between the welding pins and the ends of the flexible arms.

6. A flexible arm with variable stiffness according to claim 1, characterized in that: The end of the flexible arm is provided with a connecting piece, which is connected to the end of the flexible arm through a screw; the connecting piece is provided with an external thread, and the glue filling head is provided with an internal thread matching the external thread, and the glue filling head and the connecting piece are threadedly matched.

7. A flexible arm with variable stiffness according to claim 1, characterized in that: The air pipe joint is connected to the vacuum pump through an air guide tube.

8. A flexible arm with variable stiffness according to claim 1, characterized in that: The annular airbag is spindle-shaped after being inflated.

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