A telescopic robot arm structure with flexibility and stiffness adjustment capability

Abstract

The application discloses a telescopic mechanical arm structure with flexibility and stiffness adjusting capability, which comprises a first muscle pipeline sleeved with a first pneumatic muscle, a second muscle pipeline sleeved with a second pneumatic muscle, one end of the first muscle pipeline fixedly connected with one end of the second muscle pipeline, the other end of the first muscle pipeline fixed on a base flange, the other end of the second muscle pipeline connected with a through end of the second pneumatic muscle through a pipeline end cover, the through end of the first pneumatic muscle fixed on the base flange, the blind end of the first pneumatic muscle and the blind end of the second pneumatic muscle oppositely arranged, the first muscle pipeline and the second muscle pipeline arranged in a sleeve, one end of the sleeve fixed on the base flange, one end of a sliding cylinder fixed on a terminal flange, the other end of the sliding cylinder inserted into the sleeve, the other end of the sliding cylinder, the blind end of the first pneumatic muscle and the blind end of the second pneumatic muscle fixedly connected. The application realizes bilateral active movement and axial stiffness adjustment of the telescopic arm through oppositely arranged pneumatic muscles.

Description

Technical Field

[0001] The invention belongs to the field of robots and relates to the design of a telescopic mechanical arm structure with flexibility and rigidity adjustment capabilities. Background Art

[0002] With the rapid development of the economy and the continuous advancement of science and technology, the application of robotics has expanded from traditional industrial manufacturing to all aspects of daily life, including education, medical care, and service robots. Robots in these fields need to frequently interact with humans, placing higher demands on the robots' flexibility and safety. To meet these demands, soft robots have emerged. They use flexible materials as actuators, enabling compliant movement while ensuring safe human-robot interaction. The present invention aims to provide a flexible, telescopic robotic arm structure for a soft robot, which is used to provide the soft robot with axial linear motion freedom.

[0003] In traditional rigid robots, axial extension and retraction typically rely on linear motion components such as electric or pneumatic cylinders. Electric cylinders are driven by motors, lacking flexibility and posing safety risks. While pneumatic cylinders possess a degree of flexibility due to their pneumatic drive, their pistons must simultaneously perform sealing and motion, leading to significant wear over long periods of operation. Furthermore, cylinder creep can cause system instability. To address this issue, the present invention proposes a telescopic robotic arm structure capable of both flexibility and stiffness adjustment. Summary of the Invention

[0004] The present invention aims to address the shortcomings of the existing technology by providing a telescopic robotic arm structure with flexible and adjustable stiffness capabilities, enabling bidirectional active motion and axial stiffness adjustment. The core concept of the present invention is to use two pneumatic muscles to achieve axial motion control. Bidirectional active telescopic motion can be achieved by inflating the muscles separately, while axial stiffness can be controlled by adjusting the air pressure difference between the two muscles.

[0005] The object of the present invention is achieved by the following technical solution: a telescopic manipulator structure with flexibility and stiffness adjustment capability, comprising a base flange, a sleeve, a first muscle conduit, a second muscle conduit, a first pneumatic muscle, a second pneumatic muscle, a conduit end cap, a slide cylinder, and an end flange;

[0006] The first muscle tube is covered with a first pneumatic muscle, and the second muscle tube is covered with a second pneumatic muscle. One end of the first muscle tube is fixedly connected to one end of the second muscle tube, and the other end of the first muscle tube is fixed to the base flange. The other end of the second muscle tube is connected to the through end of the second pneumatic muscle via a tube end cap. The through end of the first pneumatic muscle is fixed to the base flange, and the blocked end of the first pneumatic muscle and the blocked end of the second pneumatic muscle are arranged opposite to each other.

[0007] The first muscle conduit and the second muscle conduit are arranged in the sleeve, one end of the sleeve is fixed on the base flange; one end of the sliding cylinder is fixed on the end flange, and the other end is inserted into the sleeve, and the other end of the sliding cylinder, the blind end of the first pneumatic muscle and the blind end of the second pneumatic muscle are fixedly connected, for transmitting the axial movement of the pneumatic muscle to the sliding cylinder to make the sliding cylinder move axially.

[0008] Further, the pneumatic muscle comprises a through-end cap, a through-end head, a through head, a silica tube, a braided mesh sleeve sleeved outside the silica tube, a blind head, and a blind-end head; the through head is provided with a gas hole for filling the silica tube with gas pressure;

[0009] The through-end head and the blind-end head are both provided with a limiting groove, and the two ends of the braided mesh sleeve are respectively installed in the limiting grooves of the through-end head and the blind-end head; the braided mesh sleeve sleeved outside the silica tube is used to limit the radial expansion of the silica tube to realize the axial elongation of the pneumatic muscle;

[0010] One end of the silica tube is sealed by being pressed tightly with the through head and the through-end head (this end is the through end of the pneumatic muscle), specifically, the through head is pressed into the silica tube to make the silica tube tightly adhere to the through head, and the through-end head is pressed tightly against the outer wall of the silica tube; the other end is sealed by being pressed tightly with the blind head and the blind-end head (this end is the blind end of the pneumatic muscle), specifically, the blind head is pressed into the silica tube to make the silica tube tightly adhere to the blind head, and the blind-end head is pressed tightly against the outer wall of the silica tube;

[0011] The through-end cap of the first pneumatic muscle cooperates with the through head of the first pneumatic muscle to fix the through end of the first pneumatic muscle on the base flange.

[0012] Further, the through-end cap of the first pneumatic muscle cooperates with the through head of the first pneumatic muscle, comprising:

[0013] The through head is provided with external threads, and the through-end cap is provided with corresponding threaded holes, which are matched and screwed with the external threads arranged on the through head.

[0014] Further, the through-end head and the blind-end head are both provided with square holes, and the through head and the blind head are both provided with square shafts; the square hole of the through-end head cooperates with the square shaft of the through head, and the square hole of the blind-end head cooperates with the square shaft of the blind head, for keeping the same circumferential movement between the through-end head and the through head and between the blind-end head and the blind head during screwing, and only retaining axial relative movement for pressing.

[0015] Further, the through-end head and the blind-end head are both provided with step faces, and the through head and the blind head are both provided with limiting faces; when pressing is in place, the step face of the through-end head is in contact with the limiting face of the through head, and the step face of the blind-end head is in contact with the limiting face of the blind head to limit the movement.

[0016] Furthermore, the open-end pressure head and the blocked-end pressure head are both provided with bite grooves for increasing friction and bite force during pressing; and / or

[0017] The open-end pressure head and the blocked-end pressure head are both provided with a flat surface for easy tightening; and / or

[0018] The through-head and the plug are both provided with arc surfaces for increasing the pressing effect.

[0019] Furthermore, the pneumatic muscle further comprises a blocking end cap and a blocking end nut;

[0020] The blocking end cap is provided with a connecting rod, and a corresponding slot is provided on the muscle tube 3 to provide movement space for the connecting rod extending from the blocking end cap;

[0021] The other end of the slide, the blocking end of the first pneumatic muscle and the blocking end of the second pneumatic muscle are fixedly connected, including: the other end of the slide, the blocking end cover of the first pneumatic muscle and the blocking end cover of the second pneumatic muscle are fixedly connected.

[0022] Furthermore, the end cap is provided with a through hole; the plug is provided with an external thread, and the external thread portion thereof passes through the through hole of the end cap and is fixed using a plug nut to avoid unnecessary twisting of the silicone tube during assembly.

[0023] Furthermore, the other end of the slide, the blocking end cap of the first pneumatic muscle, and the blocking end cap of the second pneumatic muscle are fixedly connected, including:

[0024] The connecting rod on the blocking end cover of the first pneumatic muscle is provided with a first connecting hole connected to the slide, and the connecting rod on the blocking end cover of the second pneumatic muscle is provided with a second connecting hole connected to the slide; the other end of the slide is also provided with corresponding holes, and the bolts are passed through the first connecting hole, the hole of the slide and the second connecting hole in turn and tightened with the nut.

[0025] Furthermore, during installation, liquid raw tape is used to seal between the external thread and the corresponding threaded hole.

[0026] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0027] 1. Use pneumatic muscles as actuators to make the telescopic arm flexible.

[0028] 2. The muscle charging method is used for driving, so that both sides of the telescopic arm are actively moving, and the axial stiffness of the telescopic arm can be adjusted.

[0029] 3. Use square holes with threaded screws to achieve axial compression and sealing of the silicone tube and ensure that the pneumatic muscle can be easily installed and disassembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 An overall view of a telescopic arm provided in an embodiment of the present invention.

[0032] Figure 2 Exploded view of the telescopic arm.

[0033] Figure 3 Overall cross-sectional view of the telescopic arm.

[0034] Figure 4 Detailed diagram of the pneumatic muscles.

[0035] Figure 5 Exploded view of pneumatic muscles.

[0036] Figure 6 Cross-section of a pneumatic muscle.

[0037] Figure 7 Detailed schematic diagram of the pneumatic muscle access end.

[0038] Figure 8 Schematic diagram of telescopic arm movement.

[0039] Telescopic arm main structure:

[0040] 1. Base flange; 2. Sleeve; 3. Muscle tube (3A / 3B); 4. Pneumatic muscle (4A / 4B); 5. Tube end cap

[0041] 6. Slide; 7. End flange;

[0042] The structure of pneumatic muscle 4:

[0043] 41. Through-end end cap; 42. Pressure head (42A / 42B); 43. Through-end cap; 44. Silicone tube; 45. Braided mesh; 46. Plug; 47. Plug end cap; Connecting rod 471; 48. Plug nut;

[0044] Some matching structures:

[0045] 411. Threaded hole; 421. Limiting groove; 422. Plane; 423. Square hole; 424. Engaging groove; 425. Step surface;

[0046] 431. External thread; 432. Square shaft; 433. Limiting surface; 434. Air hole. DETAILED DESCRIPTION

[0047] The present invention will be described in detail below with reference to the accompanying drawings. Unless there is any conflict, the features of the following embodiments and implementations may be combined with each other.

[0048] The present invention provides a telescopic mechanical arm structure with flexibility and stiffness adjustment capabilities, comprising a base flange, a sleeve, a first muscle pipe, a second muscle pipe, a first pneumatic muscle, a second pneumatic muscle, a pipe end cap, a slide cylinder, and an end flange;

[0049] The first muscle tube is covered with a first pneumatic muscle, and the second muscle tube is covered with a second pneumatic muscle. One end of the first muscle tube is fixedly connected to one end of the second muscle tube, and the other end of the first muscle tube is fixed to the base flange. The other end of the second muscle tube is connected to the through end of the second pneumatic muscle via a tube end cap. The through end of the first pneumatic muscle is fixed to the base flange, and the blocked end of the first pneumatic muscle and the blocked end of the second pneumatic muscle are arranged opposite to each other.

[0050] The first and second muscle tubes are positioned within a sleeve, one end of which is secured to the base flange. A slide tube, with one end secured to the terminal flange and the other end inserted into the sleeve, securely connects the other end of the slide tube, the plugged end of the first and second pneumatic muscles, and the plugged end of the second pneumatic muscle. This ensures that the axial motion of the pneumatic muscles is transmitted to the slide tube, causing the slide tube to move axially. When different air pressures are applied to the first and second pneumatic muscles, the first and second pneumatic muscles move axially, thereby driving the slide tube to move axially, i.e., the robotic arm performs telescopic motion.

[0051] Example 1:

[0052] The muscle sealing method in the embodiments of the present invention utilizes a combination of threaded tightening and inclined surface compression to ensure good sealing and convenient installation and removal. The pneumatic muscle structure is manufactured using stereolithography 3D printing technology, which not only improves manufacturing flexibility and reduces weight, but also helps control costs. The outer sleeve and slide are made of metal and are assembled with fixed connectors and other components.

[0053] See also Figures 1-8 The main structure of the telescopic arm in the embodiment of the present invention is mainly composed of the following parts: base flange 1, sleeve 2, muscle tube 3, pneumatic muscle 4, tube end cap 5, slide 6 and end flange 7. Among them, the muscle tube 3 and pneumatic muscle 4 each have two sets of identical structures, which are marked as 3A, 3B and 4A, 4B in the figure. Muscle tube 3A is the first muscle tube, muscle tube 3B is the second muscle tube, pneumatic muscle 4A is the first pneumatic muscle, and pneumatic muscle 4B is the second pneumatic muscle.

[0054] The pneumatic muscle 4, which serves as a driver, is mainly composed of the following parts: a through-end cap 41, a pressure head 42, a through-end cap 43, a silicone tube 44, a braided mesh 45, a plug 46, a plug end cap 47, and a plug end nut 48. The pressure head 42 has the same structure at both ends, marked as 42A and 42B in the figure. The pressure head 42A is the through-end pressure head, and the pressure head 42B is the plug end pressure head.

[0055] The movement of the pneumatic muscle in the embodiment of the present invention is primarily achieved by injecting air pressure into the silicone tube 44 while simultaneously limiting the radial expansion of the silicone tube 44 through a braided mesh sleeve 46 placed on the outside of the silicone tube 44 to achieve axial extension of the pneumatic muscle. The braided mesh sleeve 46 is positioned by a limiting groove 421 on the outside of the pressure head 42 to prevent the ends of the braided mesh sleeve 46 from sliding apart during movement. The seal between the silicone tube 44 and the main structure is primarily achieved by the mutual compression of the through-head 43, the plug 46, and the respective pressure heads 42A and 42B at both ends. A threaded hole 411 is provided on the through-end cap 41 for mating with the external thread 431 provided on the through-head 43 for tightening. A square hole 423 is provided on the pressure head 42 for mating with the square shaft 432 on the through-head 43 for limiting position. A flat surface 422 is also provided on the outside of the pressure head 42 to facilitate tightening using tools such as a wrench. This ensures that the main structures used to compress the silicone tube, the pressure head 42 and the through head 43, maintain the same circumferential motion during the tightening process, retaining only the axial relative motion that acts on the compression. In order to prevent excessive squeezing during muscle compression, which may damage the silicone tube 44, a step surface 425 is designed on the pressure head 42 for limiting the position during compression. When the compression is in place, the limiting surface 433 on the through head 43 will contact the step surface 425 of the pressure head 42, thereby playing a limiting role. In order to achieve a better compression effect and prevent the silicone tube 44 from loosening, a tightly arranged bite groove 424 is provided on the inner wall of the pressure head 42 to increase the friction and bite force during compression. The part used for compression on the through head 43 is designed as a circular arc surface to achieve a better compression effect. A similar structure is also provided on the plug end on the other side for sealing the silicone tube 44, except that the external thread on one side of the plug 46 is left longer and is fixed with a plug nut 48 after passing through the through hole on the plug end cover 47. This eliminates the need to rotate the entire structure to tighten it during final assembly, thus preventing unnecessary twisting of the silicone tube 44. To ensure the airtightness of the structure during actual installation, liquid raw tape is used to seal between the threaded hole 411 and the external thread 431. Furthermore, the pneumatic muscles of the present invention use air pressure as their power source. The driving air pressure is connected via an air tube to the through-end caps 41 of each of the pneumatic muscles 4 on both sides and then pumped into the silicone tube 44 through the air holes 434 reserved within the through-end to achieve movement of a single muscle.

[0056] The overall movement of the telescopic arm is achieved by respectively charging different air pressures p1 and p2 into the pneumatic muscles 4A and 4B on both sides to achieve axial telescopic movement. The corresponding hole position for connecting with the slide 6 is reserved on the end cap 47, and the pneumatic muscle as a whole is connected to the sleeve 2 through the base flange 1, and finally the axial telescopic movement of the slide 6 relative to the sleeve 2 is achieved. A muscle pipe 3 is designed on the outside of the pneumatic muscle 4 to further restrict the pneumatic muscle 4 and prevent it from producing unexpected deformation and buckling due to its own flexibility during the inflation process. At the same time, the muscle pipe 3 cooperates with the pipe end cap 5 to also play the role of fixing the pneumatic muscle as a whole to the base flange 1. For the convenience of installation, the muscle pipe 3 is designed to be a symmetrically distributed structure, and 3A and 3B are connected by bolts. At the same time, in order to transmit the movement inside the muscle pipe 3 to the external slide 6, a corresponding slot is also set on the muscle pipe 3 to provide movement space for the connecting rod 471 extending from the end cap 47. At the same time, the axial stiffness of the telescopic arm can be controlled by adjusting the air pressures p1 and p2 charged into the pneumatic muscles 4 on both sides.

[0057] It should be noted that the device embodiment shown in this embodiment matches the content of the above method embodiment. You can refer to the content of the above method embodiment and will not repeat it here.

[0058] The above embodiments are intended only to illustrate the design concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The scope of protection of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design concepts disclosed in the present invention are within the scope of protection of the present invention.

Claims

1. A telescopic robotic arm structure with flexibility and stiffness adjustment capabilities, characterized in that: It includes a base flange, a sleeve, a first muscle pipe, a second muscle pipe, a first pneumatic muscle, a second pneumatic muscle, a pipe end cover, a slide and an end flange; The first muscle tube is covered with a first pneumatic muscle, the second muscle tube is covered with a second pneumatic muscle, one end of the first muscle tube is fixedly connected to one end of the second muscle tube, the other end of the first muscle tube is fixed to the base flange, the other end of the second muscle tube is connected to the through end of the second pneumatic muscle via a tube end cap, and the through end of the first pneumatic muscle is fixed to the base flange; The first muscle tube and the second muscle tube are arranged in the sleeve, and one end of the sleeve is fixed to the base flange; one end of the slide is fixed to the end flange, and the other end is inserted into the sleeve, and the other end of the slide, the blocking end of the first pneumatic muscle, and the blocking end of the second pneumatic muscle are fixedly connected to transmit the axial movement of the pneumatic muscle to the slide, so that the slide performs axial movement; the pneumatic muscle is driven by charging, so that both sides of the telescopic arm are actively moving, and the axial stiffness of the telescopic arm can be regulated; The pneumatic muscle includes a through-end end cap, a through-end pressure head, a through-end head, a silicone tube, a braided mesh sleeve wrapped around the outside of the silicone tube, a plug, and a plug pressure head; the through-end head is provided with an air hole for filling the silicone tube with air pressure; The through-end pressure head and the blocked-end pressure head are both provided with limit grooves, and the two ends of the braided mesh sleeve are respectively installed in the limit grooves of the through-end pressure head and the blocked-end pressure head. The braided mesh sleeve sleeved on the outside of the silicone tube is used to limit the radial expansion of the silicone tube to achieve axial elongation of the pneumatic muscle; One end of the silicone tube is sealed by pressing the through-end head and the through-end pressure head together, and the other end is sealed by pressing the plug and the plug-end pressure head together; The through-end end cap of the first pneumatic muscle and the through-end head of the first pneumatic muscle cooperate to fix the through-end of the first pneumatic muscle on the base flange; The through-end pressure head and the plugging-end pressure head are both provided with square holes, and the through-end and the plugging head are both provided with square shafts; the square hole of the through-end pressure head cooperates with the square shaft of the through-end pressure head, and the square hole of the plugging-end pressure head cooperates with the square shaft of the plugging head, so as to maintain the same circumferential movement between the through-end pressure head and the through-end pressure head, and between the plugging-end pressure head and the plugging head during the tightening process, and only retain the axial relative movement acting on the tightening; The through-end pressure head and the blocking-end pressure head are both provided with a step surface, and the through-end and the blocking head are both provided with a limiting surface; when pressed into place, the step surface of the through-end pressure head contacts the limiting surface of the through-end head, and the step surface of the blocking-end pressure head contacts the limiting surface of the blocking head, thereby achieving a limiting effect.

2. A telescopic mechanical arm structure with flexibility and stiffness adjustment capabilities according to claim 1, characterized in that: The through-end end cap of the first pneumatic muscle cooperates with the through-end head of the first pneumatic muscle, including: The through head is provided with an external thread, and the through end cover is provided with a corresponding threaded hole, which is screwed together with the external thread provided on the through head.

3. The telescopic mechanical arm structure with flexibility and stiffness adjustment capability according to claim 1, characterized in that: The open-end pressure head and the blocked-end pressure head are both provided with bite grooves for increasing friction and bite force during pressing; and / or The open-end pressure head and the blocked-end pressure head are both provided with a flat surface for easy tightening; and / or The through-head and the plug are both provided with arc surfaces for increasing the pressing effect.

4. The telescopic mechanical arm structure with flexibility and stiffness adjustment capability according to claim 1, characterized in that: The pneumatic muscle also includes a blocking end cap and a blocking end nut; The blocking end cap is provided with a connecting rod, and a corresponding slot is provided on the muscle tube to provide movement space for the connecting rod extending from the blocking end cap; The other end of the slide, the blocking end of the first pneumatic muscle and the blocking end of the second pneumatic muscle are fixedly connected, including: the other end of the slide, the blocking end cover of the first pneumatic muscle and the blocking end cover of the second pneumatic muscle are fixedly connected.

5. The telescopic mechanical arm structure with flexibility and stiffness adjustment capability according to claim 4, characterized in that: The end cap is provided with a through hole; the plug is provided with an external thread, and the external thread portion thereof passes through the through hole of the end cap and is fixed using a plug nut to avoid unnecessary twisting of the silicone tube during assembly.

6. The telescopic mechanical arm structure with flexibility and stiffness adjustment capability according to claim 4, characterized in that: The other end of the slide, the blocking end cap of the first pneumatic muscle, and the blocking end cap of the second pneumatic muscle are fixedly connected, including: The connecting rod on the blocking end cover of the first pneumatic muscle is provided with a first connecting hole connected to the slide, and the connecting rod on the blocking end cover of the second pneumatic muscle is provided with a second connecting hole connected to the slide; the other end of the slide is also provided with corresponding holes, and the bolts are passed through the first connecting hole, the hole of the slide and the second connecting hole in turn and tightened with the nut.

7. A telescopic mechanical arm structure with flexibility and stiffness adjustment capability according to claim 2 or 5, characterized in that: During installation, liquid raw tape is used to seal the external thread and the corresponding threaded hole.

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