Variable stiffness flexible self-sensing actuator

Abstract

The application belongs to the technical field of soft robots, and particularly relates to a variable-stiffness flexible self-sensing actuator, which comprises a flexible actuator, a flexible magnetorheological fluid damping cavity arranged at the bottom of the flexible actuator, and magnetorheological fluid flowing in the flexible magnetorheological fluid damping cavity; and a square electromagnet arranged at the middle of the flexible actuator and used for applying a magnetic field to change the viscosity of the magnetorheological fluid. In use, the flexible actuator captures a target object after being driven by pressure fluid and being bent and deformed under pressure; the magnetorheological fluid is adsorbed in the flow channel of the flexible magnetorheological fluid damping cavity under the action of the magnetic field of the square electromagnet, greatly increasing the flow resistance of the magnetorheological fluid in the flexible magnetorheological fluid damping cavity and enhancing the clamping force of the flexible actuator, so that the object is prevented from sliding off due to insufficient clamping force caused by a complex environment after the target object is captured by the flexible actuator.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of soft robots, and particularly relates to a variable-rigidity flexible self-sensing actuator. BACKGROUND

[0002] Traditional rigid actuators are widely used in the fields of industry, medicine, food processing industry, etc., but the technical problems of large inertia, inflexible movement and high control difficulty of motor drive limit their application range, such as fragile object grabbing, underwater operation, complex space operation, etc.

[0003] Flexible actuators are currently a hot research topic, can change their own posture to adapt to complex space, have good adaptability, and have good grabbing effect on fragile and easily damaged objects and irregular objects, and are mainly applied to the grabbing scene of light objects in the food processing industry, medicine, electronic manufacturing industry, etc.

[0004] The common driving mode of flexible actuators is pressure fluid driving and intelligent material driving, and in the face of more complex and variable working requirements and operation space, flexible actuators need stronger clamping force and more variable grabbing capacity, and a single driving mode is insufficient. Therefore, a variable-rigidity flexible self-sensing actuator is urgently needed to solve the problem. SUMMARY

[0005] The purpose of the application is to provide a variable-rigidity flexible self-sensing actuator to solve the above problems.

[0006] To achieve the above purpose, the application provides the following scheme:

[0007] A variable-rigidity flexible self-sensing actuator, comprising a flexible actuator,

[0008] A flexible magnetorheological fluid damping cavity is arranged at the bottom of the flexible actuator, and magnetorheological fluid flows in the flexible magnetorheological fluid damping cavity;

[0009] A square electromagnet is arranged in the middle of the flexible actuator for applying a magnetic field to change the viscosity of the magnetorheological fluid.

[0010] Preferably, the flexible actuator comprises:

[0011] An end seat;

[0012] A flexible claw arm is fixed at one end of the end seat;

[0013] A plurality of rectangular columns are arranged on the top surface of the flexible claw arm at intervals, and the rectangular columns are fixed to the flexible claw arm;

[0014] The square electromagnet is fixed to the middle of the top surface of the flexible claw arm;

[0015] An internal communication flow channel is arranged in the flexible claw arm, one end of the internal communication flow channel is closed, and the other end is communicated with a flow channel opening, and the flow channel opening is arranged on the end seat;

[0016] A rectangular cavity is arranged in the rectangular column, and the rectangular cavity is arranged in communication with the internal communication flow channel;

[0017] The flexible magnetorheological fluid damping cavity is embedded in the inner side of the bottom of the flexible claw arm.

[0018] Preferably, the flexible magnetorheological fluid damping cavity comprises a root flexible magnetorheological fluid storage cavity, a magnetorheological fluid damping flow channel and an end flexible magnetorheological fluid storage cavity in communication;

[0019] The root flexible magnetorheological fluid storage cavity, the magnetorheological fluid damping flow channel and the end flexible magnetorheological fluid storage cavity are embedded in the inner side of the bottom of the flexible claw arm.

[0020] Preferably, the magnetorheological fluid damping flow channel is a continuous bending structure.

[0021] Preferably, a flexible sensing layer is further arranged on the bottom surface of the flexible claw arm.

[0022] Preferably, the flexible sensing layer comprises:

[0023] A signal detection part is arranged on the bottom surface of the flexible claw arm, and the signal detection part is coated with a flexible sensing material.

[0024] A flexible sensing detection signal inlet is arranged at one end of the signal detection part.

[0025] A flexible sensing detection signal outlet is arranged at the other end of the signal detection part.

[0026] Preferably, the flexible sensing material is one of a conductive filler and elastomer mixture or a conductive paste, which is printed on the bottom surface of the flexible claw arm by film printing.

[0027] Preferably, the magnetorheological fluid is a micro-nano composite magnetorheological fluid, which is prepared by mixing micron magnetic particles and nano magnetic particles and then dispersing them in a silicon oil-based carrier liquid.

[0028] Compared with the prior art, the present application has the following advantages and technical effects:

[0029] In use, the flexible actuator is bent and deformed under pressure to capture the target object after being driven by the pressure fluid; the magneto-rheological fluid is adsorbed in the flow channel of the flexible magneto-rheological fluid damping cavity under the action of the magnetic field of the square electromagnet, greatly increasing the flow resistance of the magneto-rheological fluid in the flexible magneto-rheological fluid damping cavity, and enhancing the clamping force of the flexible actuator, avoiding the situation that the target object slips off due to insufficient clamping force of the flexible actuator caused by complex environment after capturing the target object. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor under the premise of the drawings:

[0031] Figure 1 Structure diagram of the variable stiffness flexible self-sensing actuator of the present application;

[0032] Figure 2 Structure diagram of the bottom structure of the variable stiffness flexible self-sensing actuator of the present application;

[0033] Figure 3 Structure diagram of the cross-section structure of the variable stiffness flexible self-sensing actuator of the present application;

[0034] Figure 4 Structure diagram of the flexible magneto-rheological fluid damping cavity of the present application;

[0035] Figure 5 Structure diagram of the flexible sensing layer of the present application;

[0036] Figure 6 Deformation effect simulation diagram of the flexible actuator of the present application under the action of pressure fluid;

[0037] 1, flexible actuator; 2, square electromagnet; 3, flexible magneto-rheological fluid damping cavity; 4, flexible sensing layer; 1.1, end seat; 1.2, rectangular column; 1.3, flexible claw arm; 1.4, flow channel opening; 1.5, rectangular cavity; 1.6, internal communication flow channel; 3.1, root flexible magneto-rheological fluid storage cavity; 3.2, magneto-rheological fluid damping flow channel; 3.3, end flexible magneto-rheological fluid storage cavity; 4.1, flexible sensing detection signal inlet; 4.2, signal detection position; 4.3, flexible sensing detection signal outlet. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of the present application.

[0039] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0040] With reference to Figures 1 to 6 The present application discloses a variable stiffness flexible self-sensing actuator, comprising a flexible actuator 1,

[0041] A flexible magnetorheological fluid damping cavity 3 is arranged at the bottom of the flexible actuator 1, and magnetorheological fluid flows in the flexible magnetorheological fluid damping cavity 3.

[0042] A square electromagnet 2 is arranged in the middle of the flexible actuator 1, and is used for applying a magnetic field to change the viscosity of the magnetorheological fluid.

[0043] In use, after the flexible actuator 1 is driven by the pressure fluid, the flexible actuator 1 is bent and deformed under pressure to capture the target object; the magnetorheological fluid is adsorbed in the flow channel of the flexible magnetorheological fluid damping cavity 3 under the action of the magnetic field of the square electromagnet 2, greatly increasing the flow resistance of the magnetorheological fluid in the flexible magnetorheological fluid damping cavity 3, and enhancing the clamping force of the flexible actuator 1, so as to avoid the clamping force from being insufficient and the object from sliding off due to complex environment after the flexible actuator 1 captures the target object.

[0044] Further optimization scheme, the flexible actuator 1 comprises:

[0045] An end seat 1.1;

[0046] A flexible claw arm 1.3 is fixed at one end of the end seat 1.1;

[0047] A plurality of rectangular column bodies 1.2 are arranged on the top surface of the flexible claw arm 1.3 at intervals, and the rectangular column bodies 1.2 are fixedly connected with the flexible claw arm 1.3;

[0048] The square electromagnet 2 is fixedly connected to the middle of the top surface of the flexible claw arm 1.3;

[0049] An internal communication flow channel 1.6 is arranged in the flexible claw arm 1.3, one end of the internal communication flow channel 1.6 is closed, and the other end is communicated with a flow channel opening 1.4, and the flow channel opening 1.4 is arranged on the end seat 1.1;

[0050] A rectangular cavity 1.5 is arranged in the rectangular column 1.2 and is in communication with the internal communication flow channel 1.6;

[0051] The flexible magneto-rheological fluid damping cavity 3 is embedded in the inner side of the bottom of the flexible claw arm 1.3.

[0052] The rectangular column 1.2 of the flexible actuator 1 is connected with the flexible claw arm 1.3, the rectangular column 1.2 is internally provided with the rectangular cavity 1.5, the rectangular cavities 1.5 are communicated through the internal communication flow channel 1.6, the flow channel opening 1.4 is arranged on the end seat 1.1 and is in communication with the internal communication flow channel 1.6 to form the cavity structure inside the flexible actuator 1, and the flow channel opening 1.4, the rectangular cavity 1.5 and the internal communication flow channel 1.6 are in communication with each other.

[0053] In a further optimization scheme, the flexible magneto-rheological fluid damping cavity 3 comprises a root flexible magneto-rheological fluid storage cavity 3.1, a magneto-rheological fluid damping flow channel 3.2 and an end flexible magneto-rheological fluid storage cavity 3.3 in communication;

[0054] The root flexible magneto-rheological fluid storage cavity 3.1, the magneto-rheological fluid damping flow channel 3.2 and the end flexible magneto-rheological fluid storage cavity 3.3 are embedded in the inner side of the bottom of the flexible claw arm 1.3.

[0055] In a further optimization scheme, the magneto-rheological fluid damping flow channel 3.2 is a continuous bending structure.

[0056] The square electromagnet 2 is arranged between two adjacent rectangular columns 1.2 in the middle of the flexible actuator 1 and is bonded with the flexible claw arm 1.3, and the magneto-rheological fluid is adsorbed by turning on and off the power.

[0057] The flexible magneto-rheological fluid damping cavity 3 is filled with magneto-rheological fluid and is arranged in the interior of the flexible claw arm 1.3.

[0058] The flexible magneto-rheological fluid damping cavity 3 is composed of the root flexible magneto-rheological fluid storage cavity 3.1 and the end flexible magneto-rheological fluid storage cavity 3.3 in communication through the magneto-rheological fluid damping flow channel 3.2. The flexible magneto-rheological fluid damping cavity 3 is filled with magneto-rheological fluid, which is prepared by mixing micron magnetic particles and nanometer magnetic particles and then dispersing them in a silicon oil-based carrier liquid.

[0059] The principle and process of flexible magneto-rheological fluid damping cavity 3 increasing the clamping force of flexible actuator: when the flexible actuator 1 is deformed to grab the target object, the flexible magneto-rheological fluid damping cavity 3 deforms with the deformation of the flexible actuator 1, the volume of the root flexible magneto-rheological fluid storage cavity 3.1 and the end flexible magneto-rheological fluid storage cavity 3.3 changes, the internal magneto-rheological fluid flows through the magneto-rheological fluid damping flow channel 3.2, so that the pressure in the flexible magneto-rheological fluid damping cavity 3 reaches balance, the square electromagnet 2 is powered to generate a magnetic field, the magneto-rheological fluid in the flexible magneto-rheological fluid damping cavity 3 is affected by the magnetic field, the viscosity increases, the flow resistance of the magneto-rheological fluid in the magneto-rheological fluid damping flow channel 3.2 is greatly increased, and the volume of the root flexible magneto-rheological fluid storage cavity 3.1 and the end flexible magneto-rheological fluid storage cavity 3.3 will not change again under the disturbance of the external environment, that is, the deformation after grabbing the object will not change, and finally the rigidity of the flexible actuator 1 increases, achieving the purpose of "self-locking". When grabbing objects of different weights, by passing different currents to the square electromagnet 2, the effect of variable rigidity within a certain range can be achieved.

[0060] The rigidity of the flexible actuator 1 is the flow resistance of the magneto-rheological fluid in the magneto-rheological fluid damping flow channel 3.2, which is determined by the magnetic field strength generated by the square electromagnet 2 and the cross-sectional area of the magneto-rheological fluid damping flow channel 3.2. The viscosity of the magneto-rheological fluid increases with the increase of the magnetic field strength, and the flow resistance increases with the increase of the viscosity of the magneto-rheological fluid. The flow resistance of the magneto-rheological fluid flowing through the magneto-rheological fluid damping flow channel 3.2 increases with the decrease of the cross-sectional area of the magneto-rheological fluid damping flow channel 3.2. When the rigidity requirement is high, the ideal effect can be achieved by designing and adjusting the cross-sectional area of the magneto-rheological fluid damping flow channel 3.2.

[0061] Further, the magneto-rheological fluid damping flow channel 3.2 is in a meandering form, which greatly increases the flow distance of the magneto-rheological fluid while reducing the cross-section. By applying an electromagnetic field to the meandering magneto-rheological fluid damping flow channel 3.2, the flow resistance of the magneto-rheological fluid in the magneto-rheological fluid damping flow channel 3.2 can be greatly increased.

[0062] By designing the magneto-rheological fluid damping flow channel 3.2 in a meandering form, only one square electromagnet 2 needs to be provided to meet the design requirements, which greatly saves costs and improves efficiency while retaining the structure and function of the flexible actuator 1.

[0063] The variable rigidity flexible self-sensing actuator has high flexibility and wide adjustment range, solving the problem of single control scheme of the current variable rigidity flexible self-sensing actuator.

[0064] Further optimization scheme, the magneto-rheological fluid is a micro-nano composite magneto-rheological fluid, which is prepared by mixing micron magnetic particles and nano magnetic particles and then dispersing them in a silicon oil-based carrier liquid.

[0065] Further optimization scheme, the flexible sensing layer 4 is arranged on the bottom surface of the flexible claw arm 1.3.

[0066] Further optimization scheme, the flexible sensing layer 4 comprises:

[0067] The signal detection part 4.2 is a continuous bending structure, which is attached to the bottom surface of the flexible claw arm 1.3, and the flexible sensing material is coated on the signal detection part 4.2;

[0068] The flexible sensing signal inlet 4.1 is arranged at one end of the signal detection part 4.2.

[0069] The flexible sensing signal outlet 4.3 is arranged at the other end of the signal detection part 4.2.

[0070] Further optimization scheme, the flexible sensing material is one of a conductive filler and elastomer mixture or a conductive slurry, which is printed on the bottom surface of the flexible claw arm 1.3 by coating.

[0071] The flexible sensing layer 4 is composed of the flexible sensing signal inlet 4.1, the signal detection part 4.2, the flexible sensing signal outlet 4.3 and the flexible sensing material coated thereon. The flexible sensing material comprises a conductive filler and elastomer mixture or a conductive slurry, which is printed on the bottom end of the flexible actuator 1 by coating.

[0072] The principle and process of the flexible sensing layer 4 monitoring the deformation signal of the flexible actuator 1 are as follows: during the deformation process of the flexible actuator 1, the flexible sensing layer 4 located on the surface layer of the bottom end of the flexible actuator 1 deforms with the deformation of the flexible actuator 1, and the signal detection part 4.2 coated with the flexible sensing material deforms accordingly. The flexible sensing material coated on the signal detection part 4.2 can be equivalent to a long resistance wire, and with the deformation of the flexible sensing layer 4, the equivalent length and equivalent cross-sectional area of the long resistance wire change, which results in the change of the resistance value of the signal detection part 4.2. After processing and application, the motion state of the flexible actuator 1 can be obtained.

[0073] Further, the variable stiffness flexible self-sensing actuator of the present application is integrally manufactured, the manufacturing material is thermoplastic elastomer, and the standard thermoplastic processing equipment and process are used for processing and molding. The use of thermoplastic elastomer as flexible material can make the variable stiffness flexible self-sensing actuator meet different environmental requirements and achieve stronger grabbing effect. The thermoplastic processing mode ensures the flexibility, environmental friendliness and compactness of the overall structure, so that the variable stiffness flexible self-sensing actuator can well adapt to the surrounding environment, bear high pressure and quickly complete large deformation, thereby realizing flexible grabbing.

[0074] In the description of the present application, it needs to be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0075] The above-described embodiments are only to describe the preferred modes of the present application, and not to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A variable stiffness flexible self-sensing actuator, comprising a flexible actuator (1), characterized in that: a flexible magnetorheological fluid damping cavity (3) is arranged at the bottom of the flexible actuator (1), and a magnetorheological fluid flows in the flexible magnetorheological fluid damping cavity (3); a square electromagnet (2) is arranged in the middle of the flexible actuator (1) and is used for applying a magnetic field to change the viscosity of the magnetorheological fluid; the flexible actuator (1) comprises: an end seat (1.1); a flexible claw arm (1.3) fixed at one end of the end seat (1.1); a plurality of rectangular columns (1.2) are arranged on the top surface of the flexible claw arm (1.3) at intervals, and the rectangular columns (1.2) are fixedly connected with the flexible claw arm (1.3); the square electromagnet (2) is fixedly connected to the middle of the top surface of the flexible claw arm (1.3); an internal communication flow channel (1.6) is arranged in the flexible claw arm (1.3), one end of the internal communication flow channel (1.6) is closed, and the other end is communicated with a flow channel opening (1.4) arranged on the end seat (1.1); a rectangular cavity (1.5) is arranged in the rectangular column (1.2), and the rectangular cavity (1.5) is in communication with the internal communication flow channel (1.6); the flexible magnetorheological fluid damping cavity (3) is embedded in the inner side of the bottom of the flexible claw arm (1.3); the flexible magnetorheological fluid damping cavity (3) comprises a root flexible magnetorheological fluid storage cavity (3.1), a magnetorheological fluid damping flow channel (3.2) and an end flexible magnetorheological fluid storage cavity (3.3) in communication; the root flexible magnetorheological fluid storage cavity (3.1), the magnetorheological fluid damping flow channel (3.2) and the end flexible magnetorheological fluid storage cavity (3.3) are embedded in the inner side of the bottom of the flexible claw arm (1.3); the magnetorheological fluid damping flow channel (3.2) has a continuous bending structure; a flexible sensing layer (4) is arranged on the bottom surface of the flexible claw arm (1.3); the flexible sensing layer (4) comprises: a signal detection part (4.2) having a continuous bending structure, which is attached to the bottom surface of the flexible claw arm (1.3), and a flexible sensing material is applied on the signal detection part (4.2); a flexible sensing detection signal inlet (4.1) is arranged at one end of the signal detection part (4.2); a flexible sensing detection signal outlet (4.3) is arranged at the other end of the signal detection part (4.2); the flexible sensing material is a mixture of conductive filler and elastomer, or a conductive slurry, and the flexible sensing material is printed on the bottom surface of the flexible claw arm (1.3) by film coating. The magnetorheological fluid is a micro-nano composite magnetorheological fluid, which is prepared by mixing and doping micron magnetic particles and nano magnetic particles in a silicon oil based carrier liquid. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. A variable-stiffness flexible self-sensing actuator according to claim 1, characterized in that: ​

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