Self-sensing three-cavity bionic flexible finger

Abstract

The self-sensing three-cavity bionic flexible finger comprises a flexible finger base body, three cylindrical pneumatic cavities are formed in the base body, a resistance wire is wound around the base body, the upper end of the base body is open, the lower end of the base body is closed, and the base body is provided with a potentiometer signal converter electrically connected with the resistance wire. The potentiometer signal converter is in signal connection with an upper computer, the three cylindrical pneumatic cavities are connected with an external high-pressure air source, and the high-pressure air source enables the flexible finger base body to be bent by controlling the air pressure input into the three cylindrical pneumatic cavities. The potentiometer signal converter measures the resistance of the resistance wire in real time, converts the resistance into analog signals and sends the analog signals to the upper computer, the upper computer conducts air pressure regulation and control and bending angle calculation on the finger according to the input signals, and intelligent sensing control over the finger is achieved. According to the finger, the self-sensing ability of the finger can be achieved while multi-degree-of-freedom movement is achieved, and then driving and control integration of the finger can be achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of robot bionics and relates to a self-sensing three-cavity bionic flexible finger. Background Art

[0002] As an important part of the robotics field, the robot hand is also a hot spot and difficulty in research. When the dexterous hand grasps the target in the operating space, the degree of freedom of the dexterous fingers is extremely important. Multiple degrees of freedom and simple operation play a key role in the entire system. Most of the flexible dexterous fingers currently seen have three degrees of freedom, which has great limitations in the process of operating and grasping the target.

[0003] The existing finger sensing function is to install an IMU at the end of the flexible finger to sense the posture angle of the dexterous finger in real time. However, due to the large cumulative error and low accuracy of the IMU, it is impossible to accurately sense the current movement state and deflection angle of the finger. Summary of the invention

[0004] In order to solve the above technical problems existing in the prior art, the present invention proposes a self-sensing three-cavity bionic flexible finger, and its specific technical solution is as follows: A self-sensing three-cavity bionic flexible finger comprises a flexible finger substrate, wherein the flexible finger substrate is provided with three cylindrical pneumatic cavities inside and a resistance wire is wound outside, the upper end of the flexible finger substrate is open, the lower end is closed and a potentiometer signal converter electrically connected to the resistance wire is provided, the potentiometer signal converter is connected to a host computer signal, the three cylindrical pneumatic cavities are connected to an external high-pressure air source; the high-pressure air source bends the flexible finger substrate by controlling the air pressure input into the three cylindrical pneumatic cavities, the potentiometer signal converter measures the resistance of the resistance wire in real time and converts it into an analog signal and sends it to the host computer, the host computer controls the air pressure and calculates the bending angle of the finger according to the input signal, thereby realizing intelligent sensing control of the finger.

[0005] Furthermore, the flexible finger substrate is made of silicone rubber material.

[0006] Furthermore, three tracheal interfaces are provided on the upper part of the flexible finger base, the three tracheal interfaces correspond to three cylindrical pneumatic cavities, and the interfaces are sealed with flexible special glue.

[0007] Furthermore, the three cylindrical pneumatic cavities are arranged in a uniform distribution manner.

[0008] Furthermore, the potentiometer signal converter provides current to the resistance wire, and outputs a voltage analog signal by measuring the resistance of the resistance wire.

[0009] Furthermore, a groove is provided at the distal end of the finger.

[0010] Furthermore, the groove is 3 mm wide and 4 mm deep.

[0011] Furthermore, after the flexible finger substrate bends, the resistance of the resistance wire changes as the contact area between the resistance wires decreases.

[0012] Furthermore, the flexible finger base is 100 mm long, 20 mm wide and 15 mm thick.

[0013] Furthermore, the depth of the three cylindrical pneumatic cavities is 85 mm.

[0014] Beneficial effects: The finger of the present invention is easy to operate, can realize multi-degree-of-freedom movement, and can realize the self-sensing ability of the finger, thereby realizing the integration of driving and control of the flexible finger. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of a self-sensing three-cavity bionic flexible finger structure of this embodiment; Figure 2 yes Figure 1 Schematic diagram of the finger structure when the medium resistance wire is loosely wound; Figure 3 Schematic diagram of the structure of the cylindrical pneumatic cavity body of this embodiment; Figure 4 is a schematic diagram of the process of pneumatic self-sensing of fingers in this embodiment; In the figure, 1-flexible finger substrate, 2-first pneumatic cavity, 3-second pneumatic cavity, 4-third pneumatic cavity, 5-resistance wire, 6-groove, 7-potentiometer signal converter. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and technical effect of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0017] like Figures 1 to 3As shown, this embodiment discloses a self-sensing three-cavity bionic flexible finger, which has an elliptical flexible finger substrate 1, and the elliptical flexible finger substrate 1 is made of silicone rubber material, with a substrate length of 100mm, a width of 20mm, and a thickness of 15mm. Due to the particularity and superelasticity of the substrate soft material, although the finger has infinite degrees of freedom, the bending direction of the finger cannot be controlled. Therefore, three identical cylindrical pneumatic cavities are set inside the substrate, including a first pneumatic cavity 2, a second pneumatic cavity 3, and a third pneumatic cavity 4. The three cavities are preferably set in a uniform distribution manner, and the depth of the cavity is 85mm; the upper end of the substrate is open and three tracheal interfaces are provided at the upper part, and the three tracheal interfaces correspond to the three cylindrical pneumatic cavities, and the interfaces are sealed with flexible special glue; the lower end of the substrate is closed. High-pressure gas source control is adopted to adjust the air pressure of each cavity through the tracheal interface. According to the vector relationship and the synthesis of force, the bending direction of the flexible finger can be freely adjusted, thereby expanding the working space of the finger and realizing the control of the multi-degree-of-freedom bending of the finger. The finger uses a high-pressure gas source to achieve control. The overall process is pollution-free to the environment, and the operation is simple and harmless to the operator.

[0018] However, when the finger expands and bends under force based on the above design, the finger will expand horizontally or axially due to the lack of external restraint and the superelasticity of the soft material, and the input energy cannot be completely converted into the energy consumed by the bending of the finger, resulting in energy loss. Therefore, a resistance wire 5 with a wire diameter of 2 mm is wrapped around the outside of the finger to exert a certain restraining effect on the finger, so that the energy lost by the expansion of the finger can be converted to the energy consumed by the bending of the finger to the greatest extent, and the finger is not easy to explode, which can achieve energy saving and safe human-computer interaction.

[0019] At the same time, more importantly, the resistance wire 5 wrapped around the outside of the finger can also indirectly realize the self-sensing function of the finger, and sense the deformation and deflection angle of the finger in real time. Specifically, a potentiometer signal converter 7 is provided at the bottom of the flexible finger. When the cylindrical pneumatic cavity is not inflated and in a normal state, the resistance wire 5 will fit the finger tightly and wrap itself tightly. During the inflation process, the flexible finger expands and the diameter becomes larger, resulting in a decrease in the tightness of the resistance wire 5 and a change in the current path of the resistance wire. The potentiometer signal converter 7 can provide a small current for the resistance wire 5, and provide an analog output signal by measuring the resistance of the resistance wire 5. Then, the analog output signal on the potentiometer signal converter 7, i.e., the voltage value, is received by the host computer. By measuring the voltage value, the deflection displacement of the finger can be indirectly known, thereby calculating the end position of the finger and realizing the self-sensing function of the finger.

[0020] A groove 6 with a width of 3 mm and a depth of 4 mm is arranged at the distal end of the flexible finger, so as to increase the friction between the contact surface of the flexible finger and the grasped object when the flexible finger is bent to grasp the target object, thereby facilitating easy grasping of the object.

[0021] During use, if Figure 4 As shown, after the host computer sends a control signal, the air pressure is regulated by the controller. When the same compressed air is introduced into the three cylindrical pneumatic cavities, the flexible and dexterous hand will bend laterally. When the air pressure of the three cavities is different, the pressure difference formed will cause the force of each cavity to be different. At this time, the flexible and dexterous finger will bend in different directions in space, such as sideways, that is, the finger will deflect according to the control signal. After the flexible finger bends and deflects, the resistance wire 5 wrapped around the outside of the finger will disrupt the tight arrangement of the resistance wires 5 wrapped around the outside of the finger due to the force expansion of the flexible finger matrix 1, and the contact area between the resistance wires 5 will become smaller. The contact area will affect the resistance of the resistance wire 5. The resistance of the resistance wire 5 is measured by the potentiometer signal converter 7, and the voltage analog signal is output. Finally, the host computer receives the signal and calculates the deformation of the flexible finger and the bending angle according to the resistance change, realizing intelligent perception control.

[0022] In summary, the present invention tightly wraps a layer of resistance wire around the outside of the flexible finger substrate. During the bending process of the flexible finger, the deformation amount and deflection angle of the finger can be indirectly sensed based on the resistance wire wound around the outside of the flexible finger, thereby indirectly obtaining the deformation and bending performance of the flexible finger during bending. The resistance wire has high precision and can indirectly limit the energy lost by the flexible finger due to lateral expansion, and can completely convert the input energy into the energy consumed by the bending of the finger, thereby realizing energy-saving and high-precision sensing functions. In addition, different air pressure gases are introduced through three cavities to realize multi-degree-of-freedom operations in space, thereby changing the operable space of the dexterous finger, making it easier to realize the grasping operation of the space target, and increasing the working space of the flexible finger. The finger has the advantages of simple structure, easy to carry, low cost, pollution-free, large operating space, and integrated sensing and control.

[0023] In the industrial and manufacturing fields, during the automated grasping process, the finger can grasp the target object smoothly, with less restrictions on the rigidity requirements of the target object, and is not likely to cause damage to the grasped target object. It can even perform protective grasping on target objects with low rigidity and easy to be damaged, achieving non-destructive grasping and precise perception. For example, it can adapt to irregular objects such as electronic components and glass products, avoiding the rigid damage of traditional robotic arms.

[0024] It has great advantages in grasping microorganisms and less flexible objects, and is widely used in many fields such as automated grasping and rehabilitation medicine.

[0025] The above is only a preferred implementation case of the present invention and does not limit the present invention in any form. Although the implementation process of the present invention is described in detail above, for those familiar with the art, they can still modify the technical solutions recorded in the above examples, or replace some of the technical features therein with equivalents. All modifications, equivalent replacements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-sensing three-cavity bionic flexible finger, characterized in that: The invention comprises a flexible finger substrate (1), wherein three cylindrical pneumatic cavities are arranged inside the flexible finger substrate (1) and a resistance wire (5) is wound around the outside. The upper end of the flexible finger substrate (1) is open and the lower end is closed, and a potentiometer signal converter (7) electrically connected to the resistance wire (5) is arranged. The potentiometer signal converter (7) is connected to a host computer signal. The three cylindrical pneumatic cavities are connected to an external high-pressure gas source. The high-pressure gas source bends the flexible finger substrate (1) by controlling the air pressure input into the three cylindrical pneumatic cavities. The potentiometer signal converter (7) measures the resistance of the resistance wire in real time and converts the result into an analog signal and sends it to the host computer. The host computer controls the air pressure of the finger and calculates the bending angle according to the input signal, thereby realizing intelligent sensing control of the finger.

2. The bionic flexible and dexterous finger according to claim 1, characterized in that: The flexible finger base (1) is made of silicone rubber material.

3. The bionic flexible and dexterous finger according to claim 1, characterized in that: The upper part of the flexible finger base (1) is provided with three air pipe interfaces, the three air pipe interfaces correspond to three cylindrical pneumatic cavities, and the interfaces are sealed with a flexible special glue.

4. The bionic flexible and dexterous finger according to claim 1, characterized in that: The three cylindrical pneumatic cavities are arranged in a uniform distribution manner.

5. The bionic flexible and dexterous finger according to claim 1, characterized in that: The potentiometer signal converter (7) provides current to the resistance wire (5), and outputs a voltage analog signal by measuring the resistance of the resistance wire (5).

6. The bionic flexible and dexterous finger according to claim 1, characterized in that: A groove (6) is provided at the distal end of the finger.

7. The bionic flexible and dexterous finger according to claim 6, characterized in that: The groove (6) is 3 mm wide and 4 mm deep.

8. The bionic flexible and dexterous finger according to claim 1, characterized in that: After the resistance wire (5) is bent on the flexible finger base (1), the resistance of the resistance wire (5) changes as the contact area between the resistance wires (5) decreases.

9. The bionic flexible and dexterous finger according to claim 1, characterized in that: The flexible finger substrate (1) is 100 mm long, 20 mm wide and 15 mm thick.

10. The bionic flexible and dexterous finger according to claim 1, characterized in that: The depth of the three cylindrical pneumatic cavities is 85 mm.

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