A four-legged crawling soft robot based on ieap flexible actuators

Abstract

The present application relates to a kind of flexible robots, the purpose is to provide a kind of four-legged crawling soft robot based on IEAP flexible driver, can crawl on ground, and with the characteristics of simple structure, easy to assemble, small size.The technical scheme is a kind of four-legged crawling soft robot based on IEAP flexible driver, including the body arranged parallel to ground and four legs supporting body respectively in front, back, left and right parts of body, each leg is sequentially connected with foot and sole;Characterized in that: the leg is strip driver, the foot is helical driver, and the sole is sheet;The strip driver and helical driver are IEAP driver, and are electrically connected IEAP drive controller by wire respectively.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of flexible robots, in particular, a kind of four-legged crawling soft robot based on IEAP flexible driver. BACKGROUND

[0002] In recent years, flexible drivable material gradually becomes the focus of everyone's research, and soft deformable robot based on flexible drivable material is also invented. This is because the traditional rigid robot has the shortcomings of single movement form and poor flexibility due to rigid structure, and cannot adapt to complex and narrow working environment. Therefore, researchers based on flexible drivable material, by imitating soft-bodied animals in nature, study and invent flexible soft robot. The commonly used soft drivable materials include shape memory alloy / polymer, piezoelectric polymer, electroactive polymer (Electroactive Polymers, EAP) and the like. Among them, piezoelectric polymer has limited application scenarios due to the need for high voltage driving; shape memory alloy / polymer requires high driving temperature and slow deformation, which is not suitable for the construction of soft robot. And EAP material can solve the problems caused by these materials.

[0003] As one of EAPs, ionic electroactive driver (Ionic Electroactive Polymers, IEAP) has excellent response speed, large tip displacement, and can be driven at low voltage (0.5-3V), and has good stability in air and low environmental impact. It has shown great application prospects in many fields such as bionic flexible soft robot, flexible electronic device, flexible sensor and flexible medical device. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the background art, and to provide a four-legged crawling soft robot based on IEAP flexible driver, which can crawl on the ground and has the characteristics of simple structure, easy assembly and small size.

[0005] The technical solution of the present application is:

[0006] A four-legged crawling soft robot based on IEAP flexible driver, comprising a body arranged parallel to the ground and four legs supporting the body at the front, rear, left and right parts of the body, each leg being connected with a foot and a sole in turn; characterized in that: the leg is a strip-shaped driver, the foot is a spiral-shaped driver, and the sole is a sheet; the strip-shaped driver and the spiral-shaped driver are both IEAP drivers, and are respectively electrically connected to an IEAP driving controller through wires.

[0007] The four strip-shaped drivers are of the same size and are fixed on the body with the normal planes of the four strip-shaped drivers all pointing to the moving direction; the four spiral-shaped drivers are of the same size and are connected to the legs with the moving direction being perpendicular to the ground.

[0008] The body is a hard plastic plate.

[0009] The thin sheet is in the shape of a square parallel to the ground, can provide greater friction and has certain elasticity to adapt to relatively uneven road surfaces; the square design makes the robot more stable when supported by two feet.

[0010] One end of the strip-shaped driver connected to the body is connected to a wire, and one end of the spiral-shaped driver connected to the leg is connected to a wire.

[0011] The IEAP driver comprises an ionomer film and flexible electrodes arranged on two sides of the ionomer film.

[0012] The working principle of the present application is as follows:

[0013] The robot moves in the manner of imitating quadruped reptiles, adopts the diagonal step-changing method, i.e., the left front and the right back, and the right front and the left back are alternately circulated; meanwhile, the cooperation mode of each leg is 'lifting foot - stepping leg - putting foot'; the'stepping leg' movement is realized by the bending deformation of the leg driver; the 'lifting foot' and 'putting foot' movements are realized by the scaling of the foot driver; the overall movement is realized by controlling the on-off sequence and time length of each driver.

[0014] The present application has the following advantages:

[0015] The IEAP driver adopted in the present application takes cellulose as the base, is green, environmentally friendly, low in cost and excellent in performance; the leg driver adopts a strip-shaped structure, converts the front and back swing of the IEAP driver into the power of overall forward movement; the foot driver adopts a spiral-shaped structure, converts the swing of the IEAP driver into the spiral deformation of axial extension and radial extension, realizes the up-down movement of the foot driver and thus realizes the 'lifting foot' and 'putting foot' movements; the bending deformation and the spiral deformation are combined together, the movement of 'lifting foot - stepping leg - putting foot' of each leg is realized by controlling the on-off sequence of the driver, and the quadruped crawling is realized by adopting the diagonal step-changing method; meanwhile, the present application is simple in structure, convenient to assemble, small in size, and provides certain reference significance for the application of IEAP to soft bionic robots and the like. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of the three-dimensional structure of the embodiment of the present application (not in the state of being electrified).

[0017] Figure 2 is a schematic diagram of the deformation principle of the IEAP material of the embodiment of the present application.

[0018] Figure 3-1 is one of the schematic diagrams of the foot driver of the embodiment of the present application (unpowered state).

[0019] Figure 3-2 is one of the schematic diagrams of the foot driver of the embodiment of the present application (powered deformed state).

[0020] Figure 4 is the schematic diagram of the crawling movement of the embodiment of the present application.

[0021] Figure 5-1 is one of the schematic diagrams of the crawling process of the embodiment of the present application (left front right rear foot driver powered to achieve the state of left front right rear foot lifting from the state of static).

[0022] Figure 5-2 is one of the schematic diagrams of the crawling process of the embodiment of the present application (left front right rear leg driver and right front left rear leg driver powered to achieve the state of left front right rear leg moving forward and right front left rear leg exerting force backward to achieve the state of overall forward movement).

[0023] Figure 5-3 is one of the schematic diagrams of the crawling process of the embodiment of the present application (left front right rear foot driver powered to achieve the state of left front right rear foot lifting from the state of static).

[0024] Figure 5-4 is one of the schematic diagrams of the crawling process of the embodiment of the present application (right front left rear foot driver powered to achieve the state of right front left rear foot lifting).

[0025] Figure 5-5 is one of the schematic diagrams of the crawling process of the embodiment of the present application (right front left rear leg driver and left front right rear leg driver powered to achieve the state of right front left rear leg moving forward and left front right rear leg exerting force backward to achieve the state of overall forward movement).

[0026] Figure 5-6 is one of the schematic diagrams of the crawling process of the embodiment of the present application (right front left rear foot driver powered to achieve the state of right front left rear foot lifting from the state of static).

[0027] Figure 5-7 is one of the schematic diagrams of the crawling process of the embodiment of the present application (left front right rear foot driver powered to achieve the state of left front right rear foot lifting from the state of static).

[0028] Reference signs: 1-1, body; 1-2, leg; 1-3, foot; 1-4, foot sole; 2-1, ionomer film; 2-2, flexible electrode. DETAILED DESCRIPTION

[0029] IEAP consists of a central ionomer layer and two electrode layers on either side. Under the influence of an applied electric field, cations in the ionomer layer move directionally along ion channels to the cathode and accumulate continuously. Due to the volume difference between the cations and anions, the anode contracts and the cathode expands, macroscopically manifesting as bending deformation. Currently, applications based on IEAP, such as flexible grippers, flexible fingers, and biomimetic petals, have been realized. It has been proven that IEAP is very suitable as a driving material for biomimetic soft robots to realize more biomimetic applications.

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] like Figure 1 The quadrupedal crawling soft robot shown includes an IEAP drive controller (existing technology, omitted in the figure), a torso 1-1, legs 1-2, feet 1-3, and foot pads 1-4.

[0032] The bottom of the torso 1-1 is fixed to the head of the leg 1-2 with glue; the head of the foot 1-3 is fixed to the tail of the leg with glue; the foot 1-4 is fixed to the tail (i.e., the bottom) of the foot. Wires are connected to the head of the leg and the head of the foot.

[0033] The body is made of hard plastic sheet (preferably polyphenylene sulfide), the legs are strip-shaped actuators, the feet are spiral-shaped actuators, and the soles are square silicone rubber sheets; both the strip-shaped actuators and the spiral-shaped actuators are made of IEAP material (i.e., IEAP actuators); both the strip-shaped actuators and the spiral-shaped actuators are electrically connected to the IEAP drive controller via wires.

[0034] The four bar actuators are the same size and are fixed to the left front, right front, left rear, and right rear of the body, respectively. The plane normal of each bar actuator is consistent with the movement and is also parallel to the ground.

[0035] The four spiral actuators are the same size and are connected to the four bar actuators respectively, with the direction of movement perpendicular to the ground.

[0036] The feet are made of silicone rubber and are square in shape. After being connected to the bottom of the spiral actuator, they can provide greater friction and the material has a certain degree of elasticity to adapt to relatively uneven surfaces. The square design also makes the quadrupedal crawling soft robot more stable when supported by two feet.

[0037] The IEAP drive controller (existing technology, not described in detail here) includes a microcontroller, a voltage regulator module, a signal amplification module, and a control switch.

[0038] The IEAP driver includes an ionomer film 2-1 and flexible electrodes 2-2 arranged on both sides of the ionomer film, which can ensure good flexibility and also deform when powered.

[0039] Figure 2 The IEAP driver shown (prior art; see 202211087289.6) is a three-layer structure consisting of "sandwich", including flexible electrodes 2-2 on both sides and ionomer film 2-1 in the middle. The ionomer film uses carboxylated bacterial cellulose as the substrate, which is highly flexible and biodegradable, making it very suitable for preparing ion-type electroactive actuators; In addition, it is doped with ion liquid, polyvinyl alcohol, graphene and other polymer materials, which significantly enhances the physical and electrochemical properties of the actuator. The actuator has the advantages of large deformation, fast response, and strong durability. Experiments have confirmed that the IEAP driver exhibits the maximum deformation capacity under an alternating (direct) current voltage of 2V.

[0040] The spiral actuator is made from the strip actuator by thermoplastic method; the specific manufacturing method is as follows: prepare two strip actuators with the same size, curl them on the spiral mold, and place them in a dry box at 60°C for 15h to obtain the spiral actuator.

[0041] Figure 3-1 This is the state of the spiral actuator when it is not powered.

[0042] Figure 3-2 This is the shape of the spiral actuator when it is powered with a voltage of 2V, which is manifested as a shortening in the axial direction and a thickening in the radial direction, thereby realizing the "lifting" of the foot.

[0043] Figure 5 is a crawling schematic diagram of the four-legged crawling soft robot. For convenience of description, the left front leg actuator is denoted as A, the right front leg actuator is denoted as B, the left rear leg actuator is denoted as C, the right rear leg actuator is denoted as D, the left front foot actuator is denoted as a, the right front foot actuator is denoted as b, the left rear foot actuator is denoted as c, and the right rear foot actuator is denoted as d. Taking forward crawling as an example, the movement process can be divided into the following three stages:

[0044] First stage: A, B, C, D, a, b, c, and d are not powered, and the robot is in a free state; first, a and d are powered with a voltage of -2V, making the left front and right rear feet lift up Figure 5-1 ); then A and D are powered with a voltage of 2V, making the left front and right rear legs step forward, while B and C are powered with a voltage of -2V, making the right front and left rear legs step backward, making the robot move forward Figure 5-2 ); finally, a and d are powered off, making the left front and right rear feet return to the original state, showing the action of putting down the feet Figure 5-3 );

[0045] Second stage: when the robot is in the state as shown in Fig. 2, first, the voltage of 2V is applied to b and c to make the right front and left rear legs lift up as shown in Fig. 3; then the voltage of 2V is applied to B and C to make the right front and left rear legs move forward, and the voltage of -2V is applied to A and D to make the left front and right rear legs move backward, so that the robot moves forward as shown in Fig. 4; finally, the voltage of b and c is cut off to make the right front and left rear legs return to the original state, showing the action of putting down the legs as shown in Fig. 5; Figure 5-3 Figure 5-4 Figure 5-5 Figure 5-6

[0046] Third stage: different from the initial state of the first stage, the robot is initially in the state as shown in Fig. 6; the voltage of -2V is applied to a and d to make the left front and right rear legs lift up as shown in Fig. 7, and the rest of the states are the same as those of the first stage. Figure 5-6 Figure 5-7

[0047] The above process of applying and cutting off the voltage is repeated continuously, so that the whole robot can continuously crawl on the ground; by changing the size of the voltage applied to the leg driver, the front and rear deflection amplitudes of the leg driver are changed, the deflection amplitudes of the left and right sides are different, so that the robot can turn; and by changing the sequence of applying and cutting off the voltage, the flexible four-legged crawling robot can move in any direction.

[0048] The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described in the specification. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.​​​​​​

Claims

1. A four-legged crawling soft robot based on IEAP flexible driver, comprising a body (1-1) arranged parallel to the ground and four legs (1-2) supporting the body at the front, rear, left and right parts of the body respectively, each leg being sequentially connected with a foot (1-3) and a sole (1-4); characterized in that: The leg is a strip-shaped driver, the foot is a spiral-shaped driver, and the sole is a sheet; the strip-shaped driver and the spiral-shaped driver are both IEAP drivers and are electrically connected to an IEAP driver controller through wires respectively; The four strip-shaped drivers have the same size and are fixed on the body so that the normal lines of their planes all point to the moving direction; the four spiral-shaped drivers have the same size and are connected to the legs so that the moving direction is perpendicular to the ground; The body is a hard plastic plate; The sheet has a square shape parallel to the ground, can provide a large friction force, and has a certain elasticity to adapt to a relatively uneven road surface; One end of the strip-shaped driver connected to the body is connected to a wire, and one end of the spiral-shaped driver connected to the leg is connected to a wire; The moving process of the robot is divided into the following three stages: In the first stage, the left front leg driver, the right front leg driver, the left rear leg driver, the right rear leg driver, the left front foot driver, the right front foot driver, the left rear foot driver, and the right rear foot driver are not powered, and the robot is in a free state; first, the left front foot driver and the right rear foot driver are powered with a voltage of-2V, so that the left front foot and the right rear foot are lifted; then, the left front leg driver and the right rear leg driver are powered with a voltage of 2V, so that the left front leg and the right rear leg move forward, while the right front leg driver and the left rear leg driver are powered with a voltage of-2V, so that the right front leg and the left rear leg step backward, making the robot move forward; finally, the left front foot driver and the right rear foot driver are powered off, so that the left front foot and the right rear foot return to the original state, showing the action of putting down the foot; In the second stage, first, the right front foot driver and the left rear foot driver are powered with a voltage of-2V, so that the right front foot and the left rear foot are lifted; then, the right front leg driver and the left rear leg driver are powered with a voltage of 2V, so that the right front leg and the left rear leg move forward, while the left front leg driver and the right rear leg driver are powered with a voltage of-2V, so that the left front leg and the right rear leg step backward, making the robot move forward; finally, the right front foot driver and the left rear foot driver are powered off, so that the right front foot and the left rear foot return to the original state, showing the action of putting down the foot; In the third stage, the left front foot driver and the right rear foot driver are powered with a voltage of-2V to lift the left front foot and the right rear foot, and the rest of the states are the same as in the first stage.

2. The IEAP-flexural actuator based quadrupedal creeping soft robotic of claim 1, wherein: The IEAP driver includes an ionomer film (2-1) and flexible electrodes (2-2) arranged on both sides of the ionomer film.

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