An electro-hydraulic driven electrostatic adsorption soft wall-climbing robot

Abstract

This invention discloses an electro-hydraulic driven electrostatic adsorption soft climbing robot. It includes a HASEL actuator, elastic connectors, and electrostatic adsorption feet, all of which are connected to the HASEL actuator. The soft climbing robot provided by this invention achieves electro-hydraulic drive through the HASEL actuator and electrostatic adsorption through the electrostatic adsorption feet, resulting in low energy consumption and facilitating prolonged climbing. The HASEL actuator includes a sealed bag and copper electrodes. The copper electrodes are attached to the upper and lower surfaces of the electrode area of ​​the sealed bag. The copper electrodes are thin copper tapes with moderate rigidity. The use of electrodes with a certain degree of rigidity, rather than completely flexible or rigid electrodes, allows the HASEL actuator to output linearity and good dynamic response performance, while also providing a large output amplitude, ensuring fast dynamic response and a large range of motion for the soft climbing robot provided by this invention.

Description

Technical Field

[0001] This invention belongs to the field of soft robot design and control, specifically relating to an electro-hydraulic driven electrostatic adsorption soft wall-climbing robot and its motion control method. Background Technology

[0002] Climbing robots are named for their ability to move on vertical or even steeply angled walls. When equipped with specific payloads, they can perform a variety of special tasks, such as pipeline damage inspection, ship rust removal, and military surveillance.

[0003] Traditional climbing robots are rigid electromechanical systems, with complex structures and large sizes and masses. To overcome these shortcomings, research on soft climbing robots has become a priority. The main research directions for soft climbing robots include actuation methods and adhesive structures.

[0004] For drive structures, soft robots generally employ pneumatic, magnetic, or shape memory alloy (SMA) drives. While pneumatic drives offer a large range of motion and freedom in motion design, they cannot escape the need for bulky air supply equipment. Magnetic controls are limited by the magnetic environment of a laboratory setting. SMA drives consume significant energy and suffer from poor dynamic response due to their thermal actuation. Electro-hydraulic drives, primarily based on hydraulically amplified self-healing electrostatic (HASEL) actuators, exhibit limitations. Using flexible electrodes results in lower output force, while rigid electrodes, although providing higher output force, suffer from nonlinearity and poor dynamic response performance.

[0005] For adsorption structures, soft wall-climbing robots use magnetic adsorption, negative pressure adsorption, and biomimetic adsorption to achieve wall adsorption. Among them, magnetic adsorption and biomimetic adsorption have specific requirements for wall conditions, while negative pressure adsorption requires not only wall conditions but also complex equipment to generate negative pressure. Summary of the Invention

[0006] To address the problems in the background art, this invention proposes an electro-hydraulic driven electrostatic adsorption soft wall-climbing robot.

[0007] The present invention adopts the following technical solution:

[0008] I. An electrostatic adsorption soft wall-climbing robot

[0009] It includes a hydraulically amplified self-healing electrostatic HASEL driver, four electrostatic adsorption feet, two elastic connectors, and copper electrodes. The four electrostatic adsorption feet are located at the four corners of the bottom of the HASEL driver. The elastic connectors are connected between the two corners on the same side of the bottom of the HASEL driver. Copper electrodes are attached to both the upper and lower surfaces of the driver.

[0010] The HASEL actuator includes two symmetrically arranged sealed bags, a liquid dielectric, and four copper electrodes. The two sealed bags are formed by heat-sealing two BOPP films. Each sealed bag is divided into a communicating deformation area and an electrode area. The front and rear sides of the actuator are the deformation areas of the sealed bags, and the middle is the electrode area of ​​the sealed bags. Copper electrodes are attached to the upper and lower surfaces of the electrode area of ​​each sealed bag. The left and right sides of the deformation area of ​​each sealed bag are bent inward or outward to form folds to facilitate the full deformation of the actuator. The sealed bags are filled with a liquid dielectric.

[0011] The connection point between the HASEL actuator, the electrostatic adsorption foot, and the elastic connector is located on the transverse axis of symmetry of the deformation zone, and the distance between the connection point and the center point of the fold is half the width of the front and back of the deformation zone.

[0012] The copper electrode is made by cutting thin copper tape, preferably with a thickness of 0.065 mm, which does not restrict the movement of the soft climbing robot.

[0013] The electrostatic adsorption foot includes two PET films and an annular interdigital electrode located between the two PET films. The annular interdigital electrode is printed on the adhesive-coated side of the PET film, and then heat-sealed with another PET film and trimmed to form the electrostatic adsorption foot. The annular interdigital electrode is a silver paste electrode, which is formed by screen printing on the PET film.

[0014] II. A motion control method for a soft wall-climbing robot

[0015] The soft climbing robot adheres to a flat surface. By controlling the voltage state of the HASEL actuator and the electrostatic adsorption foot, the robot's movement and electrostatic adsorption state can be controlled, thereby enabling unidirectional and directional movement.

[0016] The unidirectional movement is achieved through the following steps: Assume the movement direction is to the left, the two electrostatic adsorption feet on the front left and right are electrostatic adsorption feet d and a respectively, and the two electrostatic adsorption feet on the rear left and right are electrostatic adsorption feet c and b respectively;

[0017] S1: In the initial state, no voltage is applied to the copper electrodes of the HASEL actuator. The actuator arches upward under the restoring force of the elastic connector, and the soft climbing robot is in a curled-up state.

[0018] S2: Apply a small voltage to electrostatic adsorption feet c and d, making them easy to move but still attached to the working surface. That is, the sum of the maximum static friction force between electrostatic adsorption feet c and d and the working surface and the restoring force of the elastic connector is less than the driving force of the driver under a driving voltage of 6000V. Apply a large voltage to electrostatic adsorption feet a and b, making them difficult to move. That is, the sum of the maximum static friction force between electrostatic adsorption feet a and b and the working surface and the restoring force of the elastic connector is greater than the driving force of the driver under a driving voltage of 6000V.

[0019] S3: Apply a voltage of 6000V to the HASEL actuator. Under the action of electrostatic force, the copper electrode compresses the liquid dielectric into the deformation zone of the sealed bag. The deformation zone expands and deforms, causing the actuator to overcome the resistance of the elastic connector and extend to the left, thereby driving the electrostatic adsorption feet c and d to move to the left.

[0020] S4: Apply a large voltage to electrostatic adsorption feet c and d to make them difficult to move, that is, the sum of the maximum static friction force between electrostatic adsorption feet c and d and the working surface and the restoring force of the elastic connector is greater than the driving force of the driver under a driving voltage of 6000V; apply a small voltage to electrostatic adsorption feet a and b to make them easy to move but still attached to the working surface, that is, the maximum static friction force between electrostatic adsorption feet a and b and the working surface is less than the restoring force of the elastic connector.

[0021] S5: No voltage is applied to the HASEL actuator. Under the restoring force of the elastic connector, the actuator returns to its initial curled state, causing the electrostatic adsorption feet a and b to move to the left.

[0022] S6. Repeat steps S2-S5 to achieve unidirectional movement of the soft climbing robot.

[0023] The turning movement is achieved through the following steps: Assume the rotation direction is right front, i.e. clockwise rotation, the two electrostatic adsorption feet on the front left and right are electrostatic adsorption feet d and a respectively, and the two electrostatic adsorption feet on the rear left and right are electrostatic adsorption feet c and b respectively.

[0024] S1: In the initial state, no voltage is applied to the copper electrodes of the HASEL actuator, and the soft climbing robot is in a curled-up state.

[0025] S2: Apply a small voltage to electrostatic adsorption foot c, so that it can move but still adheres to the plane, that is, the sum of the maximum static friction force of electrostatic adsorption foot c and the restoring force of the elastic connector is less than the driving force of the actuator; apply a large voltage to electrostatic adsorption feet a, b, and d, so that they are difficult to move, that is, the sum of the maximum static friction force of electrostatic adsorption feet a, b, and d and the restoring force of the elastic connector is less than the driving force of the actuator, and the maximum static friction force of electrostatic adsorption feet a, b, and d is greater than the maximum static friction force of electrostatic adsorption foot c;

[0026] S3: Apply voltage to the two copper electrodes on the rear sealing bag of the HASEL driver. Under the action of electrostatic force, the copper electrodes compress the liquid dielectric into the deformation zone of the sealing bag. The deformation zone expands and deforms, so that the rear of the driver has an extension tendency to overcome the resistance of the elastic connector. Since electrostatic adsorption feet a, b, and d are more difficult to move than c, electrostatic adsorption foot c first extends to the left front (2-3cm), and then drives electrostatic adsorption feet a and d to rotate clockwise by a certain angle (20-30°). At the same time, electrostatic adsorption foot b moves slightly to the left front (3-5mm).

[0027] S4: Apply a large voltage to the electrostatic adsorption feet a, c, and d of the soft climbing robot, making them difficult to move. That is, the sum of the maximum static friction force of the electrostatic adsorption feet a, c, and d and the restoring force of the elastic connector is less than the driving force of the actuator. The maximum static friction force of the electrostatic adsorption feet a, c, and d is greater than the maximum static friction force of the electrostatic adsorption foot b. Apply a small voltage to the electrostatic adsorption foot b, allowing it to move but still adhere to the plane. That is, the maximum static friction force of the electrostatic adsorption foot b is less than the restoring force of the elastic connector.

[0028] S5: When no voltage is applied to the HASEL driver, the rear of the driver returns to the curled state under the restoring force of the elastic connector. First, the electrostatic adsorption foot b curls up to the left front. Electrostatic adsorption foot b drives electrostatic adsorption feet a and d to rotate clockwise by a certain angle (20-30°). Electrostatic adsorption foot c moves slightly to the left front (3-5mm).

[0029] S6. Repeat steps S2-S5 to make the soft climbing robot rotate clockwise.

[0030] The present invention has the following beneficial effects:

[0031] (1) The soft climbing robot provided by the present invention combines HASEL actuator and electrostatic adsorption foot to realize linear and turning motion during the climbing process. The HASEL actuator realizes electro-hydraulic drive, and the electrostatic adsorption foot realizes wall adsorption. It consumes less energy and is conducive to long-term climbing.

[0032] (2) The copper electrode used in this invention is a thin copper tape with moderate rigidity. The use of a certain rigidity electrode instead of a completely flexible or rigid electrode makes the HASEL driver linear on the one hand, with good dynamic response performance, and large output amplitude on the other hand, ensuring that the soft wall climbing robot provided by this invention has fast dynamic response and large movement range. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the soft wall-climbing robot designed in this invention.

[0034] Figure 2This is a schematic diagram of the manufacturing process of the HASEL actuator for the soft climbing robot designed in this invention.

[0035] Figure 3 This is a schematic diagram of the manufacturing process of the electrostatic adsorption feet of the soft climbing robot designed in this invention.

[0036] Figure 4 This is a schematic diagram of the curled-up state of the soft wall-climbing robot designed in this invention.

[0037] Figure 5 This is a schematic diagram of the unidirectional movement of the soft wall-climbing robot designed in this invention.

[0038] Figure 6 This is a schematic diagram of the rotational motion of the soft wall-climbing robot designed in this invention.

[0039] Figure 7 This is a comparison diagram of the output force of the actuator designed for this invention using copper electrodes and the actuators using rigid electrodes and flexible electrodes.

[0040] In the diagram: 1-HASEL driver, 2-electrostatic adsorption foot, 3-elastic connector. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] like Figure 1 As shown, the present invention provides a soft climbing robot, including a HASEL actuator 1, two elastic connectors 3, and four electrostatic adsorption feet 2. The four electrostatic adsorption feet are located at the four corners of the bottom of the HASEL actuator, and the two elastic connectors are respectively connected to the two corners on the same side of the bottom of the HASEL actuator.

[0043] like Figure 2 As shown, the HASEL (Hydraulic Amplification Self-Healing Electrostatic) actuator includes two sealed bags, a liquid dielectric, and four copper electrodes. The sealed bags are made of heat-sealed BOPP film and include a deformation zone and an electrode zone. The copper electrodes are attached to the electrode zone of the sealed bag. The left and right sides of the deformation zone of each sealed bag are bent inwards or outwards at 45° to form folds, facilitating full deformation of the actuator. The connection point between the HASEL actuator and the electrostatic adsorption foot and elastic connector is located 5mm from the center of the fold in the deformation zone. The copper electrodes are made of thin (0.065mm) copper tape, which does not restrict the movement of the soft climbing robot. The liquid dielectric fills the sealed bags.

[0044] like Figure 3As shown, the electrostatic adsorption foot comprises two PET films and annular interdigital electrodes. The annular interdigital electrodes are silver paste electrodes, formed by screen printing on the PET films. One side of the PET film is coated with heat-sealable adhesive, and the annular interdigital electrodes are printed on the adhesive-coated side of the PET film. After printing the annular interdigital electrodes, the PET film is heat-sealed with another PET film to form the electrostatic adsorption foot.

[0045] Specifically, each elastic connector is connected to two electrostatic adsorption feet to provide a restoring force when curled up.

[0046] Example 1:

[0047] like Figure 4 As shown, when no voltage is applied to the HASEL actuator or a voltage of less than 1000V is applied, the HASEL actuator arches upward under the restoring force of the elastic connector, and the soft climbing robot is in a curled-up state.

[0048] like Figure 5 As shown, for a wall-climbing robot adsorbed onto a plane, controlling the voltage state of the HASEL actuator and the electrostatic adsorption foot controls the adsorption state of the soft robot and the movement of the HASEL actuator, achieving unidirectional movement. This is specifically achieved through the following steps:

[0049] Step 1: Apply a small voltage (200V) to electrostatic adsorption feet c and d to make them easy to move but still attached to the plane, and apply a large voltage (1000V) to electrostatic adsorption feet a and b to make them difficult to move.

[0050] Step 2: Apply voltage (6000V) to the copper electrode of the HASEL actuator. Under the action of electrostatic force, the copper electrode compresses the liquid dielectric into the deformation zone of the sealed bag, causing it to deform. This allows the soft climbing robot to overcome the resistance of the elastic connector and enter the extended state. The electrostatically adsorbed feet c and d move to the left a certain distance.

[0051] Step 3: Apply a large voltage (1000V) to the electrostatic adsorption feet c and d of the soft climbing robot to make it difficult to move; apply a small voltage (200V) to the electrostatic adsorption feet a and b to make them easy to move but still adhere to the plane.

[0052] Step 4: Without applying voltage to the HASEL actuator, the soft robot returns to its curled state under the restoring force of the elastic connector, causing electrostatic adsorption feet a and b to move a distance to the left.

[0053] Step 5: Repeat steps 1-4 to achieve unidirectional movement of the soft climbing robot.

[0054] like Figure 6As shown, for a wall-climbing robot adsorbed onto a plane, controlling the voltage state of the HASEL actuator and the electrostatic adsorption foot controls the adsorption state of the soft robot and the movement of the HASEL actuator, thus achieving a turning motion. Taking clockwise turning as an example, this is specifically achieved through the following steps:

[0055] Step 1: Apply a small voltage (200V) to electrostatic adsorption foot c so that it can move but still adheres to the plane. Apply a larger voltage (1000V) to electrostatic adsorption feet a, b, and d so that they are difficult to move.

[0056] Step 2: Apply voltage to the rear copper electrode of the HASEL actuator. Under the action of electrostatic force, the copper electrode compresses the liquid dielectric into the deformation area of ​​the sealed bag, causing it to deform. This allows the right side of the soft climbing robot to overcome the resistance of the elastic connector and extend into an extended state. Since electrostatic adsorption feet a, b, and d are more difficult to move than electrostatic adsorption foot c, electrostatic adsorption foot c first extends 2-3 cm to the left front, thereby causing electrostatic adsorption feet a and d to rotate clockwise by 20-30°. At the same time, electrostatic adsorption foot b moves slightly to the left front by 3-5 mm.

[0057] Step 3: Apply a large voltage (1000V) to the electrostatic adsorption feet a, c, and d of the soft climbing robot to make it difficult for them to move; apply a small voltage (200V) to the electrostatic adsorption foot b so that it can move but still adheres to the plane.

[0058] Step 4: Without applying voltage to the HASEL actuator, the soft robot returns to its curled-up state under the restoring force of the elastic connector. First, it causes the electrostatic adsorption foot b to curl up to the left front, then causes the electrostatic adsorption feet a and d to rotate clockwise, and the electrostatic adsorption foot c to move slightly to the left front.

[0059] Step 5: Repeat steps 1-4 to make the soft climbing robot rotate clockwise.

[0060] like Figure 7 The figure shows a comparison of the output force of the actuator designed in this invention using copper electrodes and the actuators using rigid and flexible electrodes. As can be seen from the figure, the actuator designed in this invention has a larger output force than the actuator using flexible electrodes, and its output is linear and without step phenomena compared to the actuator using rigid electrodes. This makes it suitable for applications such as soft robots and artificial muscles.

[0061] The soft climbing robot provided by this invention includes one HASEL actuator, two elastic connectors, and four electrostatic adsorption feet. The electrostatic adsorption feet and elastic connectors are connected to the HASEL actuator. The soft climbing robot provided by this invention achieves electro-hydraulic drive through the HASEL actuator and electrostatic adsorption through the electrostatic adsorption feet, resulting in low energy consumption and facilitating long-term climbing. The HASEL actuator includes two sealed bags and four copper electrodes, which are thin copper tapes with moderate rigidity. Using electrodes with a certain degree of rigidity, rather than completely flexible or rigid electrodes, allows the HASEL actuator to maintain linear output even with large output amplitude and force, resulting in good dynamic response performance. This enables the soft climbing robot provided by this invention to have fast dynamic response and a large range of motion.

[0062] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. An electrostatic adsorption soft wall-climbing robot, characterized in that, The device includes a hydraulically amplified self-healing electrostatic HASEL driver (1), four electrostatic adsorption feet (2), two elastic connectors (3) and copper electrodes. The four electrostatic adsorption feet (2) are located at the four corners of the bottom of the HASEL driver. The elastic connectors (3) are connected between the two corners on the same side of the bottom of the HASEL driver. Copper electrodes are attached to the upper and lower surfaces of the driver. The HASEL actuator includes two symmetrically arranged sealed bags, a liquid dielectric, and four copper electrodes. The two sealed bags are formed by heat-sealing two BOPP films. Each sealed bag is divided into a deformation area and an electrode area. The front and rear sides of the actuator are the deformation areas of the sealed bags, and the middle is the electrode area of ​​the sealed bags. Copper electrodes are attached to the upper and lower surfaces of the electrode area of ​​each sealed bag. The left and right sides of the deformation area of ​​each sealed bag are bent inward or outward to form folds. The sealed bags are filled with a liquid dielectric. The connection point of the HASEL actuator (1) with the electrostatic adsorption foot (2) and the elastic connector (3) is located on the transverse axis of symmetry of the deformation zone, and the distance between the connection point and the center point of the fold is half the width of the front and back of the deformation zone.

2. The electrostatic adsorption soft wall-climbing robot according to claim 1, characterized in that, The copper electrode is made by cutting thin copper tape with a thickness of 0.065 mm.

3. The electrostatic adsorption soft wall-climbing robot according to claim 1, characterized in that, The electrostatic adsorption foot (2) includes two PET films and an annular interdigital electrode, which is located between the two PET films. The annular interdigital electrode is printed on the adhesive side of the PET film and then heat-sealed with another PET film and trimmed to form the electrostatic adsorption foot. The annular interdigital electrode is a silver paste electrode, which is formed by screen printing on the PET film.

4. The motion control method for the soft climbing robot according to any one of claims 1 to 3, characterized in that, The soft climbing robot is attached to a plane. By controlling the voltage state of the HASEL actuator (1) and the electrostatic adsorption foot (2) respectively, the action of the actuator (1) and the electrostatic adsorption state of the electrostatic adsorption foot (2) are controlled, thereby realizing the unidirectional movement and turning movement of the soft climbing robot.

5. The motion control method for the soft wall-climbing robot according to claim 4, characterized in that, The unidirectional movement is achieved through the following steps: Let the direction of movement be left, and the two electrostatic adsorption feet on the front left and right be electrostatic adsorption feet d and a, respectively, and the two electrostatic adsorption feet on the rear left and right be electrostatic adsorption feet c and b, respectively. S1: In the initial state, no voltage is applied to the copper electrode of the HASEL actuator. The actuator arches upward under the restoring force of the elastic connector (3), and the soft climbing robot is in a curled-up state. S2: Apply a small voltage to electrostatic adsorption feet c and d, making them easy to move but still attached to the working surface. That is, the sum of the maximum static friction force between electrostatic adsorption feet c and d and the working surface and the restoring force of the elastic connector is less than the driving force of the driver under a driving voltage of 6000V. Apply a large voltage to electrostatic adsorption feet a and b, making them difficult to move. That is, the sum of the maximum static friction force between electrostatic adsorption feet a and b and the working surface and the restoring force of the elastic connector is greater than the driving force of the driver under a driving voltage of 6000V. S3: Apply a voltage of 6000V to the HASEL actuator. Under the action of electrostatic force, the copper electrode compresses the liquid dielectric into the deformation zone of the sealed bag. The deformation zone expands and deforms, causing the actuator to overcome the resistance of the elastic connector and extend to the left, thereby driving the electrostatic adsorption feet c and d to move to the left. S4: Apply a large voltage to electrostatic adsorption feet c and d to make them difficult to move, that is, the sum of the maximum static friction force between electrostatic adsorption feet c and d and the working surface and the restoring force of the elastic connector is greater than the driving force of the driver under a driving voltage of 6000V; apply a small voltage to electrostatic adsorption feet a and b to make them easy to move but still attached to the working surface, that is, the maximum static friction force between electrostatic adsorption feet a and b and the working surface is less than the restoring force of the elastic connector; S5: No voltage is applied to the HASEL actuator. Under the restoring force of the elastic connector, the actuator returns to its initial curled state, causing the electrostatic adsorption feet a and b to move to the left. S6. Repeat steps S2-S5 to achieve unidirectional movement of the soft climbing robot.

6. The motion control method for the soft wall-climbing robot according to claim 4, characterized in that, The steering movement is achieved through the following steps: Assume the rotation direction is right front, i.e. clockwise, and the two electrostatic adsorption feet on the front left and right are electrostatic adsorption feet d and a, respectively, and the two electrostatic adsorption feet on the rear left and right are electrostatic adsorption feet c and b, respectively. S1: In the initial state, no voltage is applied to the copper electrodes of the HASEL actuator, and the soft climbing robot is in a curled-up state. S2: Apply a small voltage to electrostatic adsorption foot c, so that it can move but still adheres to the plane, that is, the sum of the maximum static friction force of electrostatic adsorption foot c and the restoring force of the elastic connector is less than the driving force of the actuator; apply a large voltage to electrostatic adsorption feet a, b, and d, so that they are difficult to move, that is, the sum of the maximum static friction force of electrostatic adsorption feet a, b, and d and the restoring force of the elastic connector is less than the driving force of the actuator, and the maximum static friction force of electrostatic adsorption feet a, b, and d is greater than the maximum static friction force of electrostatic adsorption foot c; S3: Apply voltage to the two copper electrodes on the rear sealing bag of the HASEL driver. Under the action of electrostatic force, the copper electrodes compress the liquid dielectric into the deformation zone of the sealing bag. The deformation zone expands and deforms, so that the rear of the driver has an extension tendency to overcome the resistance of the elastic connector. The electrostatic adsorption foot c first extends to the left front, and then drives the electrostatic adsorption feet a and d to rotate clockwise. At the same time, the electrostatic adsorption foot b moves slightly to the left front. S4: Apply a large voltage to the electrostatic adsorption feet a, c, and d of the soft climbing robot to make it difficult to move. That is, the sum of the maximum static friction force of the electrostatic adsorption feet a, c, and d and the restoring force of the elastic connector is less than the driving force of the actuator. The maximum static friction force of the electrostatic adsorption feet a, c, and d is greater than the maximum static friction force of the electrostatic adsorption foot b. A small voltage is applied to the electrostatic adsorption foot b, allowing it to move but still adhere to the plane, meaning that the maximum static friction of the electrostatic adsorption foot b is less than the restoring force of the elastic connector; S5: When no voltage is applied to the HASEL driver, the rear of the driver returns to the curled state under the restoring force of the elastic connector. First, it causes the electrostatic adsorption foot b to curl to the left front. Electrostatic adsorption foot b causes electrostatic adsorption feet a and d to rotate clockwise. Electrostatic adsorption foot c moves slightly to the left front. S6: Repeat steps S2-S5 to achieve clockwise rotation of the soft climbing robot.

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