Pneumatic soft arm
By incorporating soft actuators and exoskeleton components within the soft arm, and connecting them with magnetic components and fastening rings, the output force and rigidity of the soft arm are enhanced. This addresses the shortcomings of existing soft arms in terms of precision and high output force, achieving a balance between flexibility and strength.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEBEI UNIV OF TECH
- Filing Date
- 2023-04-14
- Publication Date
- 2026-05-29
AI Technical Summary
Existing soft arms cannot effectively meet the requirements of stiffness and output force in applications that require both precision and large output force.
A pneumatic soft arm was designed, which contains a soft actuator and an exoskeleton assembly. The soft actuator is made of a material with a low elastic modulus, while the exoskeleton is made of a material with a high elastic modulus. The exoskeleton is fitted onto the outside of the soft actuator and connected by magnetic components and fastening rings to ensure synchronous movement and fixation. A V-shaped telescopic bar is set on the exoskeleton to enhance its telescopicity and output force.
It achieves the ability to output large forces while maintaining flexibility and precision, meeting the needs of various application environments.
Smart Images
Figure CN116423491B_ABST
Abstract
Description
Technical Field
[0001] This application generally relates to the field of robotic arm technology, and more particularly to a pneumatic soft arm. Background Technology
[0002] With the increasing level of automation, robotic arms have been fully utilized in industrial, medical, and special environment operations. Robotic arms can generally be divided into rigid arms and flexible arms. Rigid arms have complex structures, poor flexibility, and poor adaptability to certain working environments, while flexible arms can overcome these problems. However, existing flexible arms generally use materials with low elastic modulus, such as silicone, as actuators to apply corresponding forces to the objects being processed. It is conceivable that, to ensure flexibility and operational precision, the elastic modulus of these actuators cannot be too high. This naturally results in insufficient stiffness of the robotic arm, limiting its maximum output force. Therefore, existing flexible arms are inadequate for applications requiring both precision and large output force.
[0003] In Chinese patent document (CN115122314A), a multi-deformation mode soft actuator is disclosed to address the problem of enabling a robotic arm to perform various actions. This actuator utilizes two air channels within its main body to generate various deformation modes under pneumatic drive, including elongation deformation, contraction deformation, bidirectional bending deformation, elongation / bending coupled deformation, and contraction / bending coupled deformation. However, it still cannot solve the problem of insufficient output force and rigidity of the robotic arm in certain application scenarios. Summary of the Invention
[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a pneumatic soft arm with greater output force and stiffness.
[0005] The specific technical solution is as follows:
[0006] The pneumatic soft arm includes:
[0007] A driver assembly, comprising a soft driver, wherein a deformation cavity is formed within the soft driver and an opening on one side is provided for changing the air pressure within the deformation cavity. When the air pressure within the deformation cavity changes within a set range, the soft driver can extend or retract along its axial direction. The elastic modulus of the material of the soft driver is a first set value.
[0008] An exoskeleton assembly includes an exoskeleton with a cavity formed inside, an opening on one side, and is fitted onto a soft actuator. The exoskeleton can extend and retract with the soft actuator, and the elastic modulus of its material is a second set value, which is greater than a first set value.
[0009] As a further limitation of this application, the exoskeleton is composed of exoskeleton units, and the exoskeleton units include:
[0010] A circular skeleton, wherein at least two circular skeletons are provided, and both are coaxially sleeved on the outside of the software driver;
[0011] The V-shaped telescopic strip is provided in several parts, and its two ends on the open side are respectively connected to the adjacent circular frame.
[0012] As a further limitation of this application, in the direction of extension of the soft actuator axis, the opening directions of the V-shaped telescopic strips on two adjacent exoskeleton units are opposite.
[0013] As a further limitation of this application, the exoskeleton assembly also includes a first magnetic element;
[0014] The other side of the exoskeleton is provided with mounting holes for mounting the first magnetic component;
[0015] The software driver has a second magnetic element on the other side that cooperates with the first magnetic element.
[0016] As a further limitation of this application, the first magnetic element and / or the second magnetic element are of a plurality.
[0017] As a further limitation of this application, the driver component also includes:
[0018] An inflatable plug, which connects the opening of the soft actuator to the inflation device, has an elastic modulus of a material that is a third set value, which is greater than the second set value.
[0019] A fastening ring is fitted onto the outside of the exoskeleton to secure one side of the exoskeleton and one side of the soft actuator to the inflatable plug.
[0020] As a further limitation of this application, the outer wall of the inflator and the inner wall of the soft actuator have an anti-slip structure.
[0021] As a further limitation of this application, a deformation gap is provided on one side of the exoskeleton at the position for mounting the fastening ring.
[0022] As a further limitation of this application, the exoskeleton has at least three of the aforementioned accommodating cavities, and each of the aforementioned accommodating cavities is provided with a corresponding actuator assembly.
[0023] As a further limitation of this application, a limit rope is attached to the outer wall of the software driver.
[0024] The beneficial effects of this application are:
[0025] In applications requiring high precision, soft robotic arms need to possess both good flexibility and a certain degree of rigidity. Therefore, to maintain flexibility, the soft arm provided in this solution incorporates a soft actuator. The actuator's material needs sufficient elasticity, i.e., deformation flexibility. In practice, soft materials such as silicone are commonly used, with an elastic modulus typically around 10. 5 The elastic modulus is approximately 10 Pa. The exoskeleton is wrapped around the exoskeleton. To provide greater output force, as described in this solution, the elastic modulus of the exoskeleton material needs to be set slightly greater than that of the soft actuator. This allows the exoskeleton to move flexibly with the soft actuator to complete its preset actions; furthermore, it can provide greater output force at designated locations to complete the corresponding operational tasks. In reality, to complete the preset actions, the soft arm generally needs good extensibility. Therefore, the materials of the exoskeleton and the soft actuator also need to meet the corresponding requirements for material extensibility. Generally, the exoskeleton material is preferably TPU, with an elastic modulus typically of 10. 8 Approximately pa. In this way, the pneumatic flexible arm can perform highly flexible movements and output a set force after the movement to complete the corresponding task. Attached Figure Description
[0026] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:
[0027] Figure 1 This is a schematic diagram of the overall structure of the pneumatic soft arm after assembly, as provided in the embodiments of this application.
[0028] Figure 2 for Figure 1 Exploded view of the two parts: the exoskeleton and the soft actuator;
[0029] Figure 3 for Figure 1 Exploded view of the two parts: the inflator and the soft actuator;
[0030] The diagram is labeled as follows: 11, software actuator; 21, exoskeleton; 211, circular frame; 212, V-shaped telescopic bar; 22, first magnetic component; 12, second magnetic component; 13, air plug; 14, fastening ring; 210, deformation gap; 110, limiting rope. Detailed Implementation
[0031] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0033] Please refer to Figure 1 The pneumatic soft arm provided in this embodiment includes:
[0034] The actuator assembly includes a soft actuator 11, which has a deformation cavity formed therein and an opening on one side for filling and releasing gas to change the gas pressure in the deformation cavity. When the gas pressure in the deformation cavity changes within a set range, the soft actuator 11 can extend and retract along its axial direction. The elastic modulus of the material of the soft actuator 11 is a first set value.
[0035] An exoskeleton assembly, comprising an exoskeleton 21, wherein the exoskeleton 21 has a receiving cavity formed therein, an opening on one side, and is fitted onto the soft actuator 11. The exoskeleton 21 can extend and retract with the soft actuator 11, and the elastic modulus of its material is a second set value, wherein the second set value is greater than the first set value.
[0036] In applications requiring high precision, soft robotic arms need to possess both good flexibility and a certain degree of rigidity. Therefore, to maintain flexibility, the soft arm provided in this solution incorporates a soft actuator 11. The actuator's material needs sufficient elasticity, i.e., deformation flexibility. In practice, soft materials such as silicone are commonly used, with an elastic modulus typically around 10. 5 The elastic modulus is approximately 10 Pa. The exoskeleton 21 is wrapped around its outer side. To provide greater output force, as described in this solution, the elastic modulus of the exoskeleton 21 material needs to be set slightly greater than that of the soft actuator 11. This allows the exoskeleton 21 to move flexibly with the soft actuator 11 to complete its preset actions; and it also allows it to provide greater output force at designated locations to complete corresponding operational tasks. In reality, to complete the preset actions, the soft arm generally needs good extensibility. Therefore, the materials of the exoskeleton 21 and the soft actuator 11 also need to meet the corresponding requirements for material extensibility. Generally, the material of the exoskeleton 21 is preferably TPU, with an elastic modulus typically of 10. 8Approximately pa. In this way, the pneumatic flexible arm can perform highly flexible movements and output a set force after the movement to complete the corresponding task.
[0037] In a preferred embodiment that further enhances the output force of the soft arm, the exoskeleton 21 is composed of exoskeleton units, the exoskeleton units comprising:
[0038] At least two circular skeletons 211 are provided, and both are coaxially sleeved on the outside of the software driver 11.
[0039] V-shaped telescopic strips 212 are provided in multiple forms, and the two ends of the open side of the strips are respectively connected to the adjacent circular frame 211.
[0040] In this design, the exoskeleton 21 is equipped with an exoskeleton unit structure to enhance its scalability. When the internal soft actuator 11 extends or retracts, the V-shaped telescopic strip 212 on the external exoskeleton 21 deforms under stress, thereby improving the scalability of the soft arm. Consequently, the elastic modulus of the exoskeleton 21 material can be further increased without affecting the scalability of the soft actuator 11. Therefore, its external output force can be further increased.
[0041] In a preferred embodiment that enhances the controllability of the soft arm's movements, the opening directions of the V-shaped telescopic strips 212 on two adjacent exoskeleton units are opposite in the direction of the extension of the axis of the soft actuator 11.
[0042] To enhance the output force of the exoskeleton 21, multiple exoskeleton units arranged sequentially are required in its extension direction. To prevent the V-shaped telescopic strips 212 on adjacent exoskeleton units from forming an angle between the extension direction of the exoskeleton 21 and its axial direction at the intersection of two exoskeleton units after being subjected to force, thus preventing the soft arm from performing the corresponding action, this solution sets the V-shaped telescopic strips 212 on two adjacent exoskeleton units to have opposite opening directions. This effectively balances the tension on two adjacent exoskeleton units deviating from their axial direction after the exoskeleton 21 is subjected to the telescopic force of the soft actuator 11.
[0043] In a preferred embodiment that enhances the ease of use of the soft arm, the exoskeleton assembly further includes a first magnetic element 22;
[0044] The other side of the exoskeleton 21 is provided with mounting holes for mounting the first magnetic component 22;
[0045] On the other side of the software driver 11, there is a second magnetic element 12 that cooperates with the first magnetic element 22.
[0046] According to the above scheme, the other side of the exoskeleton 21 and the other side of the soft actuator 11 are connected by magnetic connection to maintain synchronized movement. This not only maintains the synchronicity of their extension and retraction movements, but also makes it easier to remove the exoskeleton 21 when it needs to be replaced, thereby increasing the usability of the soft arm.
[0047] The first magnetic element 22 can be configured as follows: Figure 1 The granular magnet shown, the second magnetic element 12 can be configured as follows: Figure 2 The iron plate shown is connected to the other side of the software driver 11.
[0048] In a preferred embodiment that ensures the consistency of movement between the exoskeleton and the soft actuator, there are multiple first magnetic elements 22 and / or second magnetic elements 12. Through a stronger gravitational connection between the first magnetic elements 22 and the second magnetic elements 12, the consistency of movement between the exoskeleton and the soft actuator is enhanced, resulting in more precise execution of the set actions.
[0049] In a preferred embodiment where one side of the exoskeleton is connected to one side of the soft actuator, the actuator assembly further includes:
[0050] An air plug 13 is connected between the opening of the soft driver 11 and the inflation device, and the elastic modulus of its material is a third set value, which is greater than the second set value.
[0051] Fastening ring 14 is sleeved on the outside of the exoskeleton 21 and is used to fix one side of the exoskeleton 21 and one side of the soft actuator 11 to the inflatable plug 13.
[0052] According to this solution, the soft actuator 11 and the exoskeleton 21 on its outer side are both fixed to the inflatable plug 13 with a larger elastic modulus. After the fastening ring 14 on the outer side of the exoskeleton 21 is tightened, one side of the soft actuator 11 and one side of the exoskeleton 21 will be more firmly fixed, and the internal airtightness will be better, so that the inflation device can fill the deformation cavity with gas to realize the corresponding movement of the soft arm.
[0053] In a preferred embodiment that further enhances the airtightness of the deformation cavity, the outer wall of the inflation plug 13 and the inner wall of the soft actuator 11 have an anti-slip structure, such as... Figure 3 As shown in the image.
[0054] When the deformation cavity is filled with a large amount of gas, its internal air pressure will increase significantly, which will cause the soft actuator 11 and the inflation plug 13 to tend to separate from each other. Providing an appropriate anti-slip structure between them can effectively prevent the separation caused by excessive air pressure in the deformation cavity, thereby effectively ensuring the controllability of the soft arm's movements.
[0055] The anti-slip structure between the two can be a tenon and mortise joint, a threaded connection, or other structures known in the art for increasing the strength of the connection between the two.
[0056] In a preferred embodiment that further enhances the reliability of the connection between the exoskeleton and the soft actuator, a deformation gap 210 is provided on one side of the exoskeleton 21 at the location where the fastening ring 14 is installed.
[0057] like Figure 2 As shown in the figure, on one side of the exoskeleton 21, at its root position, there is a [feature / feature] as shown in the figure. Figure 2 The deformation gap 210 shown allows the exoskeleton 21 to radially contract when the fastening ring 14 is mounted thereon, thus making the connection between the exoskeleton 21 and the soft actuator 11 more secure by the fastening ring 14. Preferably, the deformation gap 210 adopts a design such as... Figure 2 The gap structure shown is formed by V-shaped strips similar to the V-shaped telescopic strip 212.
[0058] In a preferred embodiment that ensures the soft arm can perform a flipping motion, the exoskeleton 21 has at least three accommodating cavities, and each accommodating cavity is provided with a corresponding actuator assembly.
[0059] According to this solution, the air pressure inside each soft actuator 11 can be changed by filling or deleting corresponding gas into or from each actuator assembly in the soft arm, thereby changing its length. When different soft actuators 11 have different lengths, this is reflected in the exoskeleton 21, causing the exoskeleton 21 to bend as a whole. On the other side, and as... Figure 1 The top part shown will rotate accordingly to complete the required action.
[0060] In a preferred embodiment that ensures the controllability of the soft arm's movements, a limit rope 110 is attached to the outer wall of the soft actuator 11.
[0061] According to this solution, the soft actuator 11 is secured with a limiting rope 110. Specifically, the limiting rope 110 is embedded in a designated groove on the outer wall of the soft actuator 11 to prevent the limiting rope 110 from shifting during the expansion of the soft actuator 11 and thus losing its uniform restraint on the outer wall of the soft actuator 11. When the internal air pressure of the soft actuator 11 increases, its deformation will only occur in its axial direction, such as the top of the soft actuator 11. Figure 2 The second magnetic element 12 shown will be implemented as an iron sheet. The second magnetic element 12 is embedded inside the chamber wall at the top of the soft actuator 11. This ensures that when the soft actuator 11 performs extension or bending actions, the top of the soft actuator 11 will not undergo unnecessary deformation, thereby ensuring that the corresponding actions of the soft arm can be completed smoothly.
[0062] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. A pneumatic flexible arm, characterized in that, include: The actuator assembly includes a soft actuator (11), which has a deformation cavity formed inside and an opening on one side for filling and releasing gas to change the gas pressure inside the deformation cavity. When the gas pressure inside the deformation cavity changes within a set range, the soft actuator (11) can extend and retract along its axial direction. The elastic modulus of the material of the soft actuator (11) is a first set value. The exoskeleton assembly includes an exoskeleton (21), which has a cavity inside, an opening on one side, and is fitted onto the soft actuator (11). The exoskeleton (21) can extend and retract with the soft actuator (11), and the elastic modulus of its material is a second set value, which is greater than the first set value. The exoskeleton (21) is composed of exoskeleton units, which include: At least two circular skeletons (211) are provided, and both are coaxially sleeved on the outside of the software driver (11); V-shaped telescopic strip (212), wherein there are several V-shaped telescopic strips (212), and both ends of the open side are respectively connected to the adjacent circular frame (211); In the direction of the extension of the axis of the soft actuator (11), the opening directions of the V-shaped telescopic strips (212) on two adjacent exoskeleton units are opposite; When the internal soft actuator (11) extends or retracts, the V-shaped telescopic strip (212) on the external exoskeleton (21) will deform under force, thereby improving the extensibility of the soft arm. As a result, the elastic modulus of the material of the exoskeleton (21) can be further increased, and the external output force can be further increased.
2. The pneumatic flexible arm according to claim 1, characterized in that, The exoskeleton assembly also includes a first magnetic element (22); The exoskeleton (21) has mounting holes on the other side for mounting the first magnetic component (22); The software driver (11) has a second magnetic element (12) on the other side that cooperates with the first magnetic element (22).
3. The pneumatic flexible arm according to claim 2, characterized in that, The first magnetic element (22) and / or the second magnetic element (12) have a plurality of them.
4. The pneumatic flexible arm according to claim 1, characterized in that, The driver component also includes: An air plug (13) is connected between the opening of the soft driver (11) and the inflation device, and the elastic modulus of its material is a third set value, which is greater than the second set value. Fastening ring (14), which is sleeved on the outside of the exoskeleton (21), is used to fix one side of the exoskeleton (21) and one side of the soft actuator (11) to the inflatable plug (13).
5. The pneumatic flexible arm according to claim 4, characterized in that, The outer wall of the inflator (13) and the inner wall of the soft actuator (11) have an anti-slip structure.
6. The pneumatic flexible arm according to claim 4, characterized in that, A deformation gap (210) is provided on one side of the exoskeleton (21) at the position for mounting the fastening ring (14).
7. The pneumatic flexible arm according to any one of claims 1-6, characterized in that, The exoskeleton (21) has at least three accommodating cavities, and each accommodating cavity is provided with a corresponding actuator assembly.
8. The pneumatic flexible arm according to claim 7, characterized in that, A limiting rope (110) is attached to the outer wall of the software actuator (11).