Magnetic-thermal combined regulation and control flexible phase change grabbing system and method thereof

Abstract

The invention discloses a magnetic-thermal combined regulation and control flexible phase change grabbing system. The grabbing system comprises a soft grabbing hand with magnetism, a shell and a movable magnet. A reserved hole is formed in the center of the bottom end of the shell, and the center of the soft gripper is fixedly connected with the bottom end of the shell through the reserved hole; the movable magnet is installed in an inner cavity of the shell and slides up and down in the inner cavity of the shell to be used for providing magnetic driving force for the soft gripper, and the soft gripper is used for gripping external objects. When a magnetic field is applied at normal temperature, the eight fingers of the soft gripper are flattened and attached to the shell; when the magnetic field is removed at normal temperature, the eight fingers of the soft gripper are curled downwards; when the magnetic field is removed, heating is carried out, and the active layer expands, so that the eight fingers of the soft gripper further curl downwards. According to the magnetic-thermal combined regulation and control flexible phase change grabbing system, rapid grabbing and releasing can be achieved, the grabbing state is kept without power consumption, the clamping force is regulated and enhanced, and the magnetic-thermal combined regulation and control flexible phase change grabbing system has a large application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to a flexible grasping system in the field of soft robots, in particular to a flexible phase change grasping system jointly regulated by magnetism and heat. BACKGROUND

[0002] Flexible grippers composed of soft materials have significant advantages over traditional rigid grippers in terms of safety in human-machine interaction and adaptability to grasping of complex or fragile objects. Flexible grippers have different driving mechanisms, including fluid driving, dielectric elastomer driving, magnetic driving and the like. Among them, the fluid driving mode has been most widely applied due to its convenient and diverse design and good output performance, but the heavy and complex pump-valve system required by the fluid driving mode has become the main challenge to its miniaturization and portability. The liquid-gas phase change driving mode can eliminate the pump-valve system required by the traditional fluid driving mode, however, the existing soft body gripper based on the liquid-gas phase change driving mode still has problems of slow response speed, high energy consumption of grasping and holding, etc. At the same time, the existing magnetic driving soft body gripper has the problems of weak clamping force and difficulty in regulation, and the external magnetic field device is complex, and is currently only used for grasping of small and light objects. SUMMARY

[0003] The technical problem solved by the application is to provide a flexible phase change grasping system jointly regulated by magnetism and heat, which combines the advantages of the liquid-gas phase change driving mode and the magnetic driving mode and solves the problems of the two modes respectively; simultaneously integrates carbonyl iron powder and liquid-gas phase change working medium in the silicone rubber matrix at the material level, can deform quickly under the regulation of the magnetic field, and can realize adjustable clamping force enhancement through controllable liquid-gas phase change; realizes non-power consumption grasping and holding through the pre-stretching design of the soft body gripper; and adopts a compact and light device to provide a magnetic field, so that the overall integration and portability of the flexible phase change grasping system are good.

[0004] The technical scheme for achieving the purpose of the application is as follows: I. Flexible phase change grasping system jointly regulated by magnetism and heat The flexible phase change grasping system jointly regulated by magnetism and heat comprises a soft body gripper with magnetism, an outer shell and a movable magnet; the outer shell is provided with a reserved hole at the bottom center, the center of the soft body gripper is fixedly connected with the bottom end of the outer shell through the reserved hole, and the movable magnet is installed in the inner cavity of the outer shell and slides up and down in the inner cavity of the outer shell; the movable magnet is used for providing a magnetic driving force for the soft body gripper, and the soft body gripper is used for grasping external objects. The soft gripper is mainly composed of a passive layer and an active layer both having magnetism, the passive layer and the active layer both have eight fingers, the eight fingers of the passive layer and the active layer are in a cross shape, one finger of the passive layer is bonded with one finger of the active layer respectively, the thickness of the active layer is greater than that of the passive layer, the passive layer has magnetic response capability, and the active layer has magnetic and thermal double response capability; the center of the active layer is fixedly connected with a reserved hole at the bottom end of the shell, and the passive layer is bonded on the lower end surface of the active layer.

[0005] The active layer is mainly composed of an active layer body having magnetism and a spiral heating wire embedded therein; the spiral heating wire passes through the reserved hole below the shell and is connected with an external power supply, and the bottom surface of the active layer body is bonded with the passive layer below.

[0006] When the ambient temperature and the magnetic field exist, the eight fingers of the soft gripper are unfolded horizontally and adhere to the lower surface of the shell. When the ambient temperature and the magnetic field do not exist, the eight fingers of the soft gripper are bent towards the lower end, i.e. away from the shell, and are curled and gathered towards the center point of the soft gripper to form a hollow structure between the eight fingers. When the spiral heating wire is powered on and the magnetic field does not exist, the spiral heating wire heating makes the eight fingers of the soft gripper further bend towards the lower end, i.e. away from the shell, and curl and gather towards the center point of the soft gripper.

[0007] By adjusting the heating parameters of the spiral heating wire, the volume expansion ratio of the active layer is controlled, and then the controllable adjustment of the enhanced clamping force is realized.

[0008] The target temperature range of the spiral heating wire for heating the liquid-gas phase change working medium is 20-100℃. The shell is mainly composed of a first shell, a second shell and a third shell, the first shell and the second shell are in a semi-cylindrical shell shape, the first shell and the second shell are fixedly connected at the contact end surface to form a cylindrical inner cavity, and the bottom of the first shell and the second shell has a semicircular groove structure, and the third shell is embedded in the groove structure at the bottom of the first shell and the second shell; the third shell is centrally provided with a reserved hole, the center of the soft gripper is fixedly connected to the lower surface of the third shell through the reserved hole, and the movable magnet is arranged in the inner cavity formed by the first shell and the second shell and slides up and down in the inner cavity.

[0009] When the ambient temperature and the magnetic field exist, the eight fingers of the soft gripper are unfolded horizontally and adhere to the lower surface of the third shell.

[0010] The spiral heating wire passes through the reserved hole on the third shell and is connected with the external power supply.

[0011] The movable magnet is mainly composed of a permanent magnet and a magnet operating rod, the permanent magnet is provided with a hole in the center, the lower end of the magnet operating rod is fixed in the hole in the center of the permanent magnet, and the upper end extends out of the shell and is connected with an external lifting driving power source; The permanent magnet is in the form of a cylinder, and the outer diameter of the permanent magnet is gap-fitted with the inner diameter of the cylindrical inner cavity in the shell to form a sliding pair that can slide up and down.

[0012] II. Magnetic-thermal combined regulation method of flexible phase change grabbing system The method comprises the following steps: Step one: when the soft gripper is in a cooling liquefaction state, the permanent magnet is pushed to the lower end of the inner cavity of the shell to contact the upper surface of the third shell, a magnetic field is applied to the soft gripper, and eight fingers of the soft gripper are horizontally unfolded to release an object; Step two: the magnet operating rod is pulled to move the permanent magnet away from the upper surface of the third shell until the magnetic field applied to the soft gripper is removed, eight fingers of the soft gripper in the cooling liquefaction state are bent downward and close to each other to form a hollow structure between the eight fingers; Step three: the spiral heating wire is powered to heat, the whole active layer is heated and expanded, the soft gripper is in a heating gasification state, and eight fingers of the soft gripper are further bent downward and close to each other to provide greater clamping force to grab a heavier object; Step four: after the spiral heating wire stops being powered to heat, the soft gripper cools to be in a cooling liquefaction state, and returns to the state of the soft gripper in the cooling liquefaction state in step two; Step five: when the permanent magnet is pushed again to the lower end of the inner cavity of the shell to contact the upper surface of the third shell, the soft gripper is in a state that eight fingers of the soft gripper are horizontally unfolded.

[0013] The present application has the following advantages: 1. The magnetic-thermal combined regulation flexible phase change grabbing system can quickly grab / release an object, and greatly improves the deformation response speed of the existing liquid-gas phase change driven soft gripper.

[0014] 2. The magnetic-thermal combined regulation flexible phase change grabbing system can keep the state of the grabbed object without power consumption through pre-stretching design, and solves the problem of high energy consumption of the existing liquid-gas phase change driven soft gripper.

[0015] 3. The magnetic-thermal combined regulation flexible phase change grabbing system can realize adjustable clamping force enhancement through controllable liquid-gas phase change, and solves the problem of weak and uncontrollable clamping force of the existing magnetic driven soft gripper.

[0016] 4. The magnetic-thermal combined control flexible phase change gripping system of the present invention uses a compact and lightweight device to provide the magnetic field. The flexible phase change gripping system has good overall integration and portability, which solves the problem that existing magnetically driven soft grippers require complex and large external magnetic field devices, and has great application prospects. Attached Figure Description

[0017] Figure 1 This is a partial cross-sectional schematic diagram of the flexible phase change grasping system structure in this invention; Figure 2 This is an exploded view of the flexible phase change grasping system in this invention; Figure 3 An exploded view of the soft gripper structure; Figure 4 A schematic diagram illustrating the manufacturing process of a soft gripper; Figure 5 This is a schematic diagram illustrating the principle of the flexible phase change grasping system in this invention, which can reversibly switch between three working states.

[0018] In the figure: soft gripper 1, passive layer 11, active layer 12, active layer body 121, spiral heating wire 122, outer shell 2, first outer shell 21, second outer shell 22, third outer shell 23, movable magnet 3, permanent magnet 31, magnet control lever 32. Detailed Implementation

[0019] To illustrate the technical solution and objectives of this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0020] like Figure 1 and Figure 2 As shown, the flexible phase change gripping system with combined magnetothermal control includes a magnetic soft gripper 1, a shell 2, and a movable magnet 3. A pre-drilled hole is provided at the center of the bottom end of the shell 2, and the center of the soft gripper 1 is fixedly connected to the bottom end of the shell 2 through the pre-drilled hole. The movable magnet 3 is installed in the inner cavity of the shell 2 and slides up and down in the inner cavity of the shell 2. The movable magnet 3 is used to provide magnetic driving force to the soft gripper 1, and the soft gripper 1 is used to grip external objects.

[0021] like Figure 3 and Figure 4 As shown, the soft gripper 1 is mainly composed of a passive layer 11 and an active layer 12, both of which are magnetic. Both the passive layer 11 and the active layer 12 have eight fingers, which are distributed in a star-shaped pattern. One finger of each passive layer 11 is bonded to one finger of each active layer 12. The thickness of the active layer 12 is greater than that of the passive layer 11. The passive layer 11 has magnetic response capability, and the active layer 12 has magnetothermal dual response capability. The center of the active layer 12 is fixedly connected to the reserved hole at the bottom of the outer shell 2, and the passive layer 11 is bonded to the lower end face of the active layer 12.

[0022] The active layer 12 is mainly composed of an active layer body 121 with magnetism and a spiral heating wire 122 embedded therein; the spiral heating wire 122 is connected with the external power source through a reserved hole below the shell 2 by using a copper wire, and the bottom surface of the active layer body 121 is bonded with the passive layer 11 below. Figure 4 As shown, the soft gripper 1 is made by first stretching the passive layer 11 by four-axis pre-stretching, then bonding it with the active layer 12 and releasing the pre-strain. The material of the active layer body 121 is embedded with carbonyl iron powder and liquid-gas phase change working medium, and has a magnetic-thermal dual response capability. The material of the passive layer 11 is embedded with carbonyl iron powder, and has a magnetic response capability.

[0023] At normal temperature and under the action of a magnetic field, the eight fingers of the soft gripper 1 rapidly expand horizontally and adhere to the lower surface of the shell 2.

[0024] At normal temperature and without a magnetic field, the eight fingers of the soft gripper 1 rapidly bend towards the lower end, i.e. away from the shell 2, and curl towards the center point of the soft gripper 1, thereby forming a hollow structure between the eight fingers.

[0025] When the spiral heating wire 122 is powered on and without a magnetic field, the spiral heating wire 122 heating makes the eight fingers of the soft gripper 1 bend further towards the lower end than at normal temperature and without a magnetic field, i.e. away from the shell 2, and curl towards the center point of the soft gripper 1. By adjusting the heating parameters of the spiral heating wire 122, the volume expansion ratio of the active layer 12 can be controlled, thereby realizing controllable adjustment of the enhanced clamping force. The target temperature interval of the spiral heating wire 122 for heating the liquid-gas phase change working medium is 20-100℃.

[0026] As shown in Figure 1 and Figure 2 , the shell 2 is mainly composed of a first shell 21, a second shell 22 and a third shell 23. The first shell 21 and the second shell 22 are semi-cylindrical shells, and the first shell 21 and the second shell 22 are fixedly connected at the contact end face to form a cylindrical inner cavity. The bottom of the first shell 21 and the second shell 22 has a semicircular groove structure, and the third shell 23 is fixedly embedded in the groove structure at the bottom of the first shell 21 and the second shell 22. The third shell 23 is centrally provided with a reserved hole, and the center of the soft gripper 1 is fixedly connected to the lower surface of the third shell 23 through the reserved hole. The movable magnet 3 is arranged in the inner cavity formed by the first shell 21 and the second shell 22 and slides up and down in the inner cavity. At normal temperature and under the action of a magnetic field, the eight fingers of the soft gripper 1 are in a horizontally expanded state and adhere to the lower surface of the third shell 23. The spiral heating wire 122 needs to be electrically connected, and a copper wire is used to pass through the reserved hole on the third shell 23 and connect with the external power source.

[0027] The movable magnet 3 is mainly composed of a permanent magnet 31 and a magnet control lever 32. The permanent magnet 31 has a hole in the center. The lower end of the magnet control lever 32 is fixed in the hole in the center of the permanent magnet 31, and the upper end extends out of the outer shell 2 and is connected to the external lifting drive power source.

[0028] The permanent magnet 31 is cylindrical, and its outer diameter is fitted with the inner diameter of the cylindrical cavity in the outer shell 2 to form a sliding pair that can slide up and down.

[0029] The magnetic-cold combined control method for the flexible phase change grasping system of the present invention includes the following steps: Step 1: When the soft gripper 1 is in a cooled and liquefied state, the permanent magnet 31 is pushed until the lower end of the inner cavity of the outer shell 2 contacts the upper surface of the third outer shell 23, thus applying a magnetic field to the soft gripper 1. The eight fingers of the soft gripper 1 are then horizontally extended to release the object.

[0030] Step 2: Pull the magnet control lever 32 to move the permanent magnet 31 away from the upper surface of the third outer shell 23 until the magnetic field applied to the soft gripper 1 is removed. The eight fingers of the soft gripper 1 in the cooled and liquefied state bend downward and close together to form a hollow structure between the eight fingers.

[0031] Step 3: The spiral heating wire 122 is energized and heated, causing the active layer 12 to expand as a whole. The soft gripper 1 is in a heated and vaporized state. The eight fingers of the soft gripper 1 bend downward and close together to provide greater clamping force to grasp heavier objects.

[0032] Step 4: After the spiral heating wire 122 stops heating, the soft gripper 1 cools down and enters a cooling liquefaction state, returning to the normal state of the soft gripper 1 in Step 2.

[0033] Step 5: When the permanent magnet 31 is pushed again until the lower end of the inner cavity of the outer shell 2 contacts the upper surface of the third outer shell 23, the soft gripper 1 is subjected to a magnetic field and is in a state where the eight fingers of the soft gripper 1 are horizontally spread out.

[0034] like Figure 5 As shown, specifically, the soft gripper 1 has a dual magnetothermal response capability and can achieve three different working states, determined according to the following method: When a magnetic field is applied at room temperature, the eight fingers of the soft gripper 1 quickly flatten and adhere to the lower surface of the third housing 23 due to magnetic attraction, and the soft gripper 1 is in the first working state of opening to release the object. When the magnetic field is removed at room temperature, the eight fingers of the soft gripper 1 quickly curl inward, and the soft gripper 1 is in the second working state of being closed to grasp objects. When the magnetic field is removed, the spiral heating wire 122 is powered to heat, and due to the liquid-gas phase change of the embedded liquid-gas phase change working medium, the active layer 12 expands, so that the eight fingers of the soft gripper 1 are further curled inward, which can provide adjustable greater clamping force for grabbing heavier objects, and the soft gripper 1 is in the third working state of enhanced grabbing.

[0035] Due to the rapid application / removal of the magnetic field and the rapid release of the elastic potential energy stored in the structure of the soft gripper 1, the soft gripper 1 can quickly and reversibly switch between the first working state and the second working state, realizing the rapid grabbing and releasing of the object. Due to the reversibility of the liquid-gas phase change of the liquid-gas phase change working medium and the elasticity of the two-component silicone rubber material, by controlling the heating / cooling of the spiral heating wire 122, the soft gripper 1 can reversibly switch between the second working state and the third working state. Due to the natural curling of the eight fingers of the soft gripper 1 inward to form a hollow structure at room temperature and without the action of the magnetic field, the soft gripper 1 can maintain the state of grabbing the object without power consumption in the second working state. In the third working state, by adjusting the heating parameters of the spiral heating wire 122, the volume expansion ratio of the active layer 12 can be controlled, and then the controllable adjustment of the enhanced clamping force can be realized.

[0036] By controlling the movement of the movable magnet 3 in the cylindrical inner cavity of the shell 2, the application or removal of the magnetic field to the soft gripper 1 can be controlled. Specifically, when the permanent magnet 31 contacts the upper surface of the third shell 23, the movable magnet 3 applies a magnetic field to the soft gripper 1; when the distance between the permanent magnet 31 and the upper surface of the third shell 23 exceeds the effective action distance of the permanent magnet 31 to the soft gripper 1, the movable magnet 3 removes the magnetic field applied to the soft gripper 1.

[0037] The material components of the active layer body 121 include carbonyl iron powder with a mass fraction of 15%-40%, liquid-gas phase change working medium with a mass fraction of 15%-40%, and low-hardness two-component silicone rubber with a mass fraction of 40%-60%, wherein the liquid-gas phase change working medium can be a single component or a mixture of multiple components; the material components of the passive layer 11 include carbonyl iron powder with a mass fraction of 40%-60% and high-hardness two-component silicone rubber with a mass fraction of 40%-60%; the low-hardness two-component silicone rubber is a two-component silicone rubber with a Shore hardness between 0A5A, and the mixed mass ratio of A and B components in the low-hardness two-component silicone rubber is 1:1; the high-hardness two-component silicone rubber is a two-component silicone rubber with a Shore hardness between 10A50A, and the mixed mass ratio of A and B components in the high-hardness two-component silicone rubber is 1:1; the liquid-gas phase change working medium is a fluid with a boiling point between 20℃ and 100℃; the material of the permanent magnet 31 is neodymium iron boron magnet.

[0038] While the application has been described by way of example with reference to preferred embodiments, it is to be understood that this application is not limited to the embodiments disclosed, but is intended to cover modifications and variations within the spirit and scope of the application. Therefore, the scope of the application is defined not by the detailed description of the application but by the following claims, wherein reference to an alternative embodiment includes reference to all features describing that embodiment.

Claims

1. A flexible phase change grasping system with combined magnetocaloric control, characterized in that: The device includes a magnetic soft gripper (1), a housing (2), and a movable magnet (3); the housing (2) has a pre-drilled hole at the center of its bottom end, and the center of the soft gripper (1) is fixedly connected to the bottom end of the housing (2) through the pre-drilled hole; the movable magnet (3) is installed in the inner cavity of the housing (2) and slides up and down in the inner cavity of the housing (2); the movable magnet (3) is used to provide magnetic driving force to the soft gripper (1), and the soft gripper (1) is used to grasp external objects; The soft gripper (1) is mainly composed of a passive layer (11) and an active layer (12) that are both magnetic. Both the passive layer (11) and the active layer (12) have eight fingers. The eight fingers of the passive layer (11) and the active layer (12) are distributed in a star shape. One finger of each passive layer (11) is bonded to one finger of each active layer (12). The thickness of the active layer (12) is greater than the thickness of the passive layer (11). The center of the active layer (12) is fixedly connected to the reserved hole at the bottom of the outer shell (2). The passive layer (11) is bonded to the lower end face of the active layer (12).

2. The flexible phase change grasping system with combined magnetocaloric control according to claim 1, characterized in that: The active layer (12) is mainly composed of a magnetic active layer body (121) and a spiral heating wire (122) embedded therein; the spiral heating wire (122) is connected to an external power source, and the bottom surface of the active layer body (121) is bonded to the passive layer (11) below.

3. The flexible phase change grasping system with combined magnetocaloric control according to claim 2, characterized in that: At room temperature and under the influence of a magnetic field, the eight fingers of the soft gripper (1) spread out horizontally and adhere to the lower surface of the outer shell (2); At room temperature and without the influence of a magnetic field, the eight fingers of the soft gripper (1) bend downwards and come together to form a hollow structure between the eight fingers; When the spiral heating wire (122) is energized and there is no magnetic field, the heating of the spiral heating wire (122) causes the eight fingers of the soft gripper (1) to bend and close further towards the lower end than when at room temperature and without magnetic field.

4. The flexible phase change grasping system with combined magnetocaloric control according to claim 3, characterized in that: By adjusting the heating parameters of the spiral heating wire (122), the volume expansion ratio of the active layer (12) is controlled, thereby achieving controllable adjustment of the enhanced clamping force.

5. The flexible phase change grasping system with combined magnetocaloric control according to claim 4, characterized in that: The spiral heating wire (122) heats the liquid-gas phase change working fluid in the temperature range of 20-100℃.

6. The flexible phase change grasping system with combined magnetocaloric control according to claim 1, characterized in that: The outer shell (2) is mainly composed of a first outer shell (21), a second outer shell (22) and a third outer shell (23). The first outer shell (21) and the second outer shell (22) are semi-cylindrical shells. The first outer shell (21) and the second outer shell (22) are fixedly connected at the contact end face to form a cylindrical inner cavity. The bottom of the first outer shell (21) and the second outer shell (22) has a semi-annular groove structure. The outer periphery of the third outer shell (23) is fixedly embedded in the groove structure at the bottom of the first outer shell (21) and the second outer shell (22). The third outer shell (23) has a reserved hole in the center. The center of the soft gripper (1) is fixedly connected to the lower surface of the third outer shell (23) through the reserved hole. The movable magnet (3) is set in the inner cavity composed of the first outer shell (21) and the second outer shell (22) and slides up and down in the inner cavity.

7. A flexible phase change grasping system with combined magnetocaloric control according to claim 2 or 6, characterized in that: The spiral heating wire (122) passes through a reserved hole on the third outer shell (23) and is connected to an external power source.

8. The flexible phase change grasping system with combined magnetocaloric control according to claim 1, characterized in that: The movable magnet (3) is mainly composed of a permanent magnet (31) and a magnet control lever (32). The permanent magnet (31) has a hole in the center. The lower end of the magnet control lever (32) is fixed in the hole in the center of the permanent magnet (31), and the upper end extends out of the outer shell (2) and is connected to the external lifting drive power source. The permanent magnet (31) is cylindrical, and the outer diameter of the permanent magnet (31) is in clearance fit with the inner diameter of the cylindrical inner cavity in the outer shell (2) to form a sliding pair that can slide up and down.

9. A method for combined magnetocaloric control of a flexible phase change grasping system according to any one of claims 1-8, characterized in that: The method is implemented by the following steps: Step 1: When the soft gripper (1) is in a cooled and liquefied state, and the permanent magnet (31) is pushed to the lower end of the inner cavity of the outer shell (2) to contact the upper surface of the third outer shell (23), a magnetic field is applied to the soft gripper (1), and the eight fingers of the soft gripper (1) are horizontally spread out to release the object; Step 2: Pull the magnet control lever (32) to move the permanent magnet (31) away from the upper surface of the third shell (23) until the magnetic field applied to the soft gripper (1) is removed. The eight fingers of the soft gripper (1) in the cooled and liquefied state bend downward and close together to form a hollow structure between the eight fingers. Step 3: The spiral heating wire (122) is energized and heated, causing the active layer (12) to expand as a whole. The soft gripper (1) is in a heated and vaporized state. The eight fingers of the soft gripper (1) are further bent downward and joined together to provide greater clamping force to grasp heavier objects. Step 4: After the spiral heating wire (122) stops being powered on, the soft gripper (1) is cooled and liquefied, returning to the state of the soft gripper (1) in the state of cooling and liquefiing in Step 2; Step 5: When the permanent magnet (31) is pushed to the lower end of the inner cavity of the outer shell (2) and contacts the upper surface of the third outer shell (23), the soft gripper (1) is subjected to a magnetic field and is in a state where the eight fingers of the soft gripper (1) are horizontally spread out.

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