Programmable bionic 4D printing intelligent gripper with electro-repair and visual feedback functions

Abstract

The invention discloses a programmable bionic 4D printing intelligent gripper with electrogenerated repair and visual feedback functions, and belongs to the field of structural design and manufacturing of intelligent grippers, the bionic design of the gripper is derived from a toe-facing efficient enveloping mechanism and color changing characteristics of the foot of a tree-dwelling chameleon and a primate phalanx structure; the main body structure of the gripper is two groups of driving structures which cooperatively move in opposite directions and are formed by four bionic fingers, each finger comprises three active driving units including a near section, a middle section and a far section, the main body structure of the gripper is formed by a shape memory polymer, and a conductive network formed by a conductive polymer is arranged in the main body structure; differentiated electric excitation is applied to a plurality of independently designed conductive contacts, so that the conductive network of the middle layer generates Joule heat, and the Joule heat generated when the conductive network is electrified can realize one or more of the following functions: electro-induced damage repair, visual feedback, programmable selective driving and self-adaptive rigidity dynamic adjustment.

Description

Technical Field

[0001] This invention belongs to the field of intelligent gripper structure design and manufacturing, specifically relating to a programmable biomimetic 4D printed intelligent gripper with electro-healing and visual feedback functions. Background Technology

[0002] In recent years, with the rapid development of additive manufacturing technology and smart materials, flexible intelligent grippers based on the concept of soft robots have gradually become a cutting-edge scientific field. Compared with traditional grippers, which are generally composed of rigid components and drive units and achieve gripping functions through transmission mechanisms, intelligent grippers effectively solve problems such as complex control, poor adaptability, or lack of status feedback functions. As a core actuator in the field of robot operation and intelligent equipment, intelligent grippers are widely used in industrial automation, medical assistance, space exploration, and special operations, and are gradually developing towards intelligence and multi-functionality.

[0003] Currently, the field of intelligent grippers faces the following problems: poor durability and short service life: grippers are prone to damage during cyclical operation, and the repair process is complex and the repair cycle is long; lack of status perception and feedback mechanisms: grippers lack effective feedback methods, making it difficult for operators to obtain gripper information in real time for adjustment and intervention; limitations in drive and control methods: existing grippers mostly use pneumatic or hydraulic drives, resulting in a complex overall system structure and difficulty in achieving independent and precise control; limited adaptive stiffness adjustment capability: variable stiffness mechanisms usually rely on phase change materials or structural design, which have problems such as slow response, the need for additional drive sources, or complex required structures, making it difficult to achieve rapid and reversible dynamic stiffness adjustment; difficulty in balancing system integration and lightweighting: existing grippers are usually composed of actuators and transmission mechanisms, leading to structural redundancy and increased weight.

[0004] With the development of advanced manufacturing technologies and materials, 3D printing has gradually evolved into 4D printing. 4D printing introduces a time dimension to 3D printing, enabling printed objects to autonomously undergo programmable shape and function responses under specific external stimuli. Based on 4D printing technology, the field of flexible intelligent grippers requires an innovative biomimetic intelligent gripper design and manufacturing method to solve the aforementioned problems, achieving integrated functionality such as electro-induced damage repair, state visualization, programmable selective actuation, adaptive stiffness adjustment, high integration, and lightweighting.

[0005] In summary, there is an urgent need in this field for a programmable biomimetic 4D printing smart gripper with electro-healing and visual feedback capabilities. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the above-mentioned technical field and to provide a programmable biomimetic 4D printed smart gripper with electro-healing and visual feedback functions. It uses the foot of an arboreal chameleon and the finger bones of primates as biomimetic prototypes, and combines 4D printing technology with smart materials to achieve a multifunctional integrated smart gripper design.

[0007] The technical solution of the present invention is as follows:

[0008] A programmable biomimetic 4D printed smart gripper with electro-healing and visual feedback functions is based on the efficient anti-toe envelopment mechanism and color-changing characteristics of the foot of the arboreal chameleon and combined with the phalangeal structure of primates. It includes: 2n evenly distributed biomimetic fingers, which form n sets of anti-toe envelopment groups for coordinated anti-toe movement.

[0009] The bionic finger comprises a proximal segment 10, joint one 11, middle segment 12, joint two 13, and distal segment 14 connected in sequence. The proximal segment 10 is the longest, followed by the middle segment 12, and the distal segment 14 is the shortest. All three are active deformation units.

[0010] When a third electrical excitation is applied to the conductive contacts I104 and II105 on the proximal segment 10, the proximal segment 10 bends;

[0011] When a third electrical excitation is applied to the conductive contacts III121 and IV122 on the middle section 12, the middle section 12 bends;

[0012] When a third electrical excitation is applied to the conductive contacts V141 and VI142 on the distal section 14, the distal section 14 bends.

[0013] When a third electrical excitation is applied to the conductive contact I104 and conductive contact VI142, the bionic finger bends as a whole.

[0014] The gripper is integrally formed using additive manufacturing technology; the proximal segment 10, middle segment 12, distal segment 14, and joint of the bionic finger are all three-layer composite structures.

[0015] The near section 10, middle section 12, and far section 14 are all composed of a thermochromic PLA outer layer 101, a conductive PLA network 102, and a thermochromic PLA inner layer 103.

[0016] Each joint is composed of a joint TPU 85A outer layer 111, a conductive PLA network 102, and a joint TPU 85A inner layer 112;

[0017] The conductive PLA network 102 generates Joule heat when energized, which can be used to achieve one or more of the following functions: as an electrical excitation for pre-grab shape programming, as a first electrical excitation (damage repair electrical excitation), as a second electrical excitation (status display electrical excitation), as a third electrical excitation (drive electrical excitation), and as a fourth electrical excitation (modulus control electrical excitation).

[0018] The bionic finger has bionic scale structures 143 on the inner sides of the proximal segment 10, middle segment 12, and distal segment 14 to increase the interface friction coefficient and improve gripping stability.

[0019] The conductive PLA network 102 in the three-layer composite structure is composed of graphene and basic PLA material. Graphene is uniformly dispersed in the PLA matrix in the form of filler, giving the composite material the dual functions of shape memory and conductivity.

[0020] The bionic finger consists of a three-layer composite structure with a thickness ratio of 3:2:1 from the inner to the outer layer, comprising the proximal segment 10, the middle segment 12, the distal segment 14, and the joint.

[0021] The conductive PLA network 102 can be controlled independently by partition, and it is provided with multiple conductive contacts that apply electrical excitation; a groove is provided at the position of the temperature-changing PLA outer layer 101 corresponding to the conductive contact.

[0022] A method for using a programmable bionic intelligent gripper with electro-healing and visual feedback functions, employing the aforementioned programmable bionic 4D printed intelligent gripper with electro-healing and visual feedback functions, is as follows:

[0023] 1) Damage Repair

[0024] A first electrical excitation is applied to the contacts near the area requiring damage repair. The conductive PLA network 102 generates Joule heat through the electrical excitation, heating the outer layer 101 and inner layer 102 of the thermochromic PLA to above their glass transition temperature Tg, thereby activating the shape memory effect of the material and repairing cracks and structural failures.

[0025] 2) Status display

[0026] A second electrical excitation is applied to the bionic finger that requires status display, and the status of the bionic finger is visualized by changing the color of the thermochromic material; the outer layer 101 and the inner layer 103 of the thermochromic PLA are reversible thermochromic materials with color-changing function triggered by heat.

[0027] 3) Crawler driver

[0028] When it is necessary to grasp an object, a third electrical excitation is applied to the bionic finger, which can apply independent and precise deformation control to the proximal segment 10, middle segment 12 and distal segment 14 of each finger, activate the application of pre-made differentiated internal stress at different levels, so that the molecular chain segments of SMP can resume movement, complete the flexible and adjustable grasping action and program the grasping posture in real time.

[0029] 4) Modulus control

[0030] When stiffness adaptive adjustment is required, a fourth electrical excitation is applied to the bionic finger to actively regulate the softness and hardness of the SMP, so that the gripper has active flexibility similar to biological muscles; it is in a softer state when approaching the object to prevent collision, and switches to a high-stiffness state during the gripping phase to provide a stable grip.

[0031] A method for manufacturing a programmable bionic intelligent gripper with electro-healing and visual feedback functions, using the aforementioned programmable bionic intelligent gripper with electro-healing and visual feedback functions, includes the following specific manufacturing steps:

[0032] Step 1: The gripper is made of materials according to the functional zoning requirements. The outer layer of the finger joints (proximal joint 10, middle joint 12, distal joint 14) is made of thermochromic PLA material, and the outer layer of the joint is made of TPU 85A. The interior is a conductive network formed by conductive PLA.

[0033] Step 2: The gripper model is established. The finger joint model of the gripper is designed and built using the 3D modeling software SolidWorks. The joints are designed using the generative shape design module and part design module in the 3D modeling software CATIA. The three-layer structure of the model is inserted and combined in different geometric forms to facilitate the subsequent assignment of material properties.

[0034] Step 3: After the 3D model is built, it is imported into the slicing software for processing: First, the material properties are assigned to each layer. The innermost and outermost layers of the grasping finger joint structure are made of thermochromic PLA material, the innermost and outermost layers of the joint are made of TPU 85A material, and the overall internal conductive network is made of conductive PLA.

[0035] Then, parameters such as printing speed, infill density, and printing support are set, and the 3D model is adjusted to a suitable position and angle to balance surface quality and molding efficiency. Finally, Gcode code files are generated.

[0036] The printing speed is adjusted to achieve variable speed printing. The inner layer of the bionic finger uses a higher printing speed, while the outer layer uses a lower printing speed. During the printing process, pre-made differentiated internal stresses are applied to different layers. Programmable grasping can be achieved by changing the printing speed gradient or selecting different differentiated printing speed areas.

[0037] Step 4: Using multi-material FDM manufacturing process, shape memory polymer is used as the main material to print the above Gcode file into shape, accurately realizing the layer-by-layer construction of the gripper structure. After forming, the support structure is removed and the surface is finished to finally obtain a smart gripper with complete structure and integrated functions.

[0038] The working principle of the programmable bionic intelligent gripper with electro-healing and visual feedback functions of this invention is as follows:

[0039] Taking the proximal segment 10 of the bionic finger as an example: its internal conductive network resistance is R, its mass is m, its specific heat capacity is c, the applied electrical excitation is U, the energizing time is t, and the artificial shaping angle when heated to above Tg is θ. s The bending angle after shape programming and electrical excitation is θ a The initial temperature of the gripper is T0, the temperature after energization is T1, the elastic modulus of the material at the initial temperature T0 is E0, the elastic modulus of the material at the temperature T1 after energization is E1, and the temperature coefficient of the material's modulus is k.

[0040] The deformation angle of the single finger joint of the gripper after applying shape-programmed electrical excitation is:

[0041] ;

[0042] The shape fixation rate of the gripper's single finger joint after applying shape programming electrical excitation is:

[0043] ;

[0044] The deformation rate of a single finger joint of the gripper after applying three-electric excitation:

[0045] ;

[0046] After a power-on time t, the energy obtained by the gripper is:

[0047] ;

[0048] After a power-on time t, the temperature rise of the gripper is:

[0049] ;

[0050] After an energizing time t, the elastic modulus of the gripper is:

[0051] .

[0052] This invention provides a programmable biomimetic 4D-printed smart gripper with electrocautery and visual feedback functions, belonging to the field of smart gripper structural design and manufacturing. The biomimetic design of this gripper is derived from the efficient anti-toe envelopment mechanism and color-changing characteristics of the foot of the arboreal chameleon, as well as the phalanx structure of primates. The main structure of the gripper consists of four biomimetic fingers forming two sets of coordinated opposing motion drive structures. Each finger contains three active drive units: the proximal phalanx, the middle phalanx, and the distal phalanx. Its main structure is made of shape memory polymer, with an internal conductive network composed of conductive polymer. By applying differentiated electrical excitation to multiple independently designed conductive contacts, Joule heating is generated in the intermediate conductive network. When the conductive network is energized, the Joule heating generated can achieve one or more of the following functions: electrocautery repair, visual feedback, programmable selective actuation, and adaptive stiffness dynamic adjustment.

[0053] The beneficial effects and advantages of this invention compared with the prior art are as follows:

[0054] 1. The gripper is prone to damage when gripping sharp or rough objects or when used repeatedly. In-situ, active damage repair can be achieved by applying a first electrical excitation (damage repair electrical excitation) to raise the temperature of the shape memory polymer above the glass transition temperature, thereby activating the shape memory effect.

[0055] 2. By monitoring the stress, working mode, and damage warning information of the gripper, a second electrical excitation (status display electrical excitation) can be applied to make the temperature of the thermochromic PLA reach the color change threshold to change the material color, thereby realizing the visualization of the system status and giving the gripper a visual feedback function.

[0056] 3. Based on the segmented design of the intelligent gripper and the independent distribution of conductive contacts, the proximal, middle and distal segments of each finger can be independently and precisely deformed by applying a third-point excitation (driving electrical excitation). This supports independent adjustment of voltage, timing and duration of action for different segments, enabling flexible and programmable selective driving.

[0057] 4. By applying a fourth electrical excitation (modulating the SMP modulus electrical excitation), the stiffness of the SMP is actively controlled, giving the gripper active flexibility similar to biological muscles. This provides a unique advantage in scenarios involving precise interaction or grasping fragile objects. It maintains a softer state during the approach phase to prevent collisions, switches to a high-stiffness state during the grasping phase to provide a stable grip, and returns to a softer state during the release phase for a gentle detachment.

[0058] 5. By using additive manufacturing technology to integrate multiple polymer materials into one piece, the traditional multi-part assembly method is abandoned. Polymer materials have the characteristics of being lightweight and high-strength, which not only enables the high integration and lightweighting of the gripper structure, but also provides room for innovative design of complex functional components. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the overall structure of a programmable biomimetic 4D printed smart gripper with electro-healing and visual feedback functions according to the present invention.

[0060] Figure 2 This is a schematic diagram of the finger-shaped envelope structure of a programmable bionic 4D printed smart gripper with electro-healing and visual feedback functions according to the present invention.

[0061] Figure 3 This is a schematic diagram of the overall design structure of the knuckles and joints of a programmable bionic 4D printed smart gripper with electro-repair and visual feedback functions according to the present invention.

[0062] Figure 4 This is a schematic diagram of the three-layer composite structure of the knuckles and joints of a programmable bionic 4D printed smart gripper with electro-repair and visual feedback functions according to the present invention.

[0063] Figure 5 This is a schematic diagram of the conductive contact distribution of a single finger of a programmable bionic 4D printed smart gripper with electro-repair and visual feedback functions according to the present invention.

[0064] Figure 6 This is a schematic diagram of the conductive contact structure of a programmable biomimetic 4D printed smart gripper with electro-repair and visual feedback functions according to the present invention.

[0065] Figure 7 This is a schematic diagram of the biomimetic scale structure of a programmable biomimetic 4D printed smart gripper with electro-repair and visual feedback functions according to the present invention.

[0066] In the attached diagram:

[0067] 1. Finger 1; 2. Finger 2; 3. Finger 3; 4. Finger 4; 10. Proximal segment; 11. Joint 1; 12. Middle segment; 13. Joint 2; 14. Distal segment; 101. Thermochromic PLA outer layer; 102. Conductive PLA network; 103. Thermochromic PLA inner layer; 104. Conductive contact I; 105. Conductive contact II; 111. Joint TPU 85A outer layer; 112. Joint TPU 85A inner layer; 121. Conductive contact III; 122. Conductive contact IV; 141. Conductive contact V; 142. Conductive contact VI; 143. Bionic scale structure. Detailed Implementation

[0068] Example 1:

[0069] A programmable bionic 4D printed smart gripper with electro-repair and visual feedback functions is based on the efficient enveloping mechanism and color-changing characteristics of the foot of the arboreal chameleon and combined with the phalangeal structure of primates. It includes four bionic fingers: finger 1, finger 2, finger 3, and finger 4, which are evenly distributed and form two sets of opposing enveloping groups for coordinated opposing movements.

[0070] The bionic finger comprises a proximal segment 10, joint one 11, middle segment 12, joint two 13, and distal segment 14 connected in sequence. The proximal segment 10 is the longest, followed by the middle segment 12, and the distal segment 14 is the shortest. All three are active deformation units.

[0071] When a third electrical excitation is applied to the conductive contacts I104 and II105 on the proximal segment 10, the proximal segment 10 bends;

[0072] When a third electrical excitation is applied to the conductive contacts III121 and IV122 on the middle section 12, the middle section 12 bends;

[0073] When a third electrical excitation is applied to the conductive contacts V141 and VI142 on the distal section 14, the distal section 14 bends.

[0074] When a third electrical excitation is applied to the conductive contact I104 and conductive contact VI142, the bionic finger bends as a whole.

[0075] The gripper is integrally formed using additive manufacturing technology; the proximal segment 10, middle segment 12, distal segment 14, and joint of the bionic finger are all three-layer composite structures.

[0076] The near section 10, middle section 12, and far section 14 are all composed of a thermochromic PLA outer layer 101, a conductive PLA network 102, and a thermochromic PLA inner layer 103.

[0077] Each joint is composed of a joint TPU 85A outer layer 111, a conductive PLA network 102, and a joint TPU 85A inner layer 112;

[0078] The conductive PLA network 102 generates Joule heat when energized, which can be used to achieve one or more of the following functions: as an electrical excitation for pre-grab shape programming, as a first electrical excitation (damage repair electrical excitation), as a second electrical excitation (status display electrical excitation), as a third electrical excitation (drive electrical excitation), and as a fourth electrical excitation (modulus control electrical excitation).

[0079] The bionic finger has bionic scale structures 143 on the inner sides of the proximal segment 10, middle segment 12, and distal segment 14 to increase the interface friction coefficient and improve gripping stability.

[0080] The conductive PLA network 102 in the three-layer composite structure is composed of graphene and basic PLA material. Graphene is uniformly dispersed in the PLA matrix in the form of filler, giving the composite material the dual functions of shape memory and conductivity.

[0081] The bionic finger consists of a three-layer composite structure with a thickness ratio of 3:2:1 from the inner to the outer layer, comprising the proximal segment 10, the middle segment 12, the distal segment 14, and the joint.

[0082] The bionic finger has an inner layer thickness ratio of 3, firstly to provide greater deformation recovery force, and secondly because the inner layer is prone to wear and damage when in contact with the object being grasped. The middle layer has a thickness ratio of 2, because it acts as a heat source when energized, and its own deformation recovery effect is poor. The outermost layer has a thickness ratio of 1, which uses an inner and outer clamping repair mechanism to ensure the uniformity of electrical damage repair and effectively avoid uneven deformation that may be caused by unilateral repair.

[0083] The conductive PLA network 102 can be controlled independently by partition, and it is provided with multiple conductive contacts that apply electrical excitation; a groove is provided at the position of the temperature-changing PLA outer layer 101 corresponding to the conductive contact.

[0084] The bionic finger does not have adjacent conductive contacts merging, and conductive contacts are not placed at the joints; if conductive contacts are placed at the joints, the conductive network is prone to deterioration or even failure due to material fatigue.

[0085] Example 2:

[0086] A method for using a programmable bionic intelligent gripper with electrocautery and visual feedback functions is as follows:

[0087] 1) Damage Repair

[0088] A first electrical excitation is applied to the contacts near the area requiring damage repair. The conductive PLA network 102 generates Joule heat through the electrical excitation, heating the outer layer 101 and inner layer 102 of the thermochromic PLA to above their glass transition temperature Tg, thereby activating the shape memory effect of the material and repairing cracks and structural failures.

[0089] 2) Status display

[0090] A second electrical excitation is applied to the bionic finger that requires status display, and the status of the bionic finger is visualized by changing the color of the thermochromic material; the outer layer 101 and the inner layer 103 of the thermochromic PLA are reversible thermochromic materials with color-changing function triggered by heat.

[0091] Thermochromic materials refer to a class of smart materials whose color can change reversibly with temperature. The core of the color-changing function of the thermochromic PLA material selected in this invention lies in uniformly mixing thermochromic liquid crystals (TCLCs) into the PLA matrix in the form of microcapsules. Its color-changing principle is based on the optical properties of liquid crystal molecules being extremely sensitive to temperature.

[0092] 3) Crawler driver

[0093] When it is necessary to grasp an object, a third electrical excitation is applied to the bionic finger, which can apply independent and precise deformation control to the proximal segment 10, middle segment 12 and distal segment 14 of each finger, activate the application of pre-made differentiated internal stress at different levels, so that the molecular chain segments of SMP can resume movement, complete the flexible and adjustable grasping action and program the grasping posture in real time.

[0094] 4) Modulus control

[0095] When stiffness adaptive adjustment is required, a fourth electrical excitation is applied to the bionic finger to actively regulate the softness and hardness of the SMP, so that the gripper has active flexibility similar to biological muscles; it is in a softer state when approaching the object to prevent collision, and switches to a high-stiffness state during the gripping phase to provide a stable grip.

[0096] Taking finger 1 as an example: A fourth electrical excitation is applied to the internal conductive network of finger 1, causing the internal conductive PLA network 102 to generate a Joule heating effect in a short time, which causes the overall temperature of the three-layer composite structure to rise rapidly. In order to achieve precise control of modulus adjustment and ensure that the main structure after the gripper shape programming is not changed, it is necessary to control the voltage magnitude and energizing time, and strictly control the overall temperature of the material below its glass transition temperature Tg. Within this temperature range, although the shape memory polymer does not undergo a macroscopic phase transition from the glassy state to the elastic state, the frequency of its molecular chain segment motion gradually increases with the temperature, which can achieve a certain degree of continuous and reversible dynamic adjustment of the material modulus.

[0097] Example 3:

[0098] A method for manufacturing a programmable bionic intelligent gripper with electro-healing and visual feedback functions, the specific manufacturing steps of which are as follows:

[0099] Step 1: The gripper is made of materials according to the functional zoning requirements. The outer layer of the finger joints (proximal joint 10, middle joint 12, distal joint 14) is made of thermochromic PLA material, and the outer layer of the joint is made of TPU 85A. The interior is a conductive network formed by conductive PLA.

[0100] Step 2: The gripper model is established. The finger joint model of the gripper is designed and built using the 3D modeling software SolidWorks. The joints are designed using the generative shape design module and part design module in the 3D modeling software CATIA. The three-layer structure of the model is inserted and combined in different geometric forms to facilitate the subsequent assignment of material properties.

[0101] Step 3: After the 3D model is built, it is imported into the slicing software for processing: First, the material properties are assigned to each layer. The innermost and outermost layers of the grasping finger joint structure are made of thermochromic PLA material, the innermost and outermost layers of the joint are made of TPU 85A material, and the overall internal conductive network is made of conductive PLA.

[0102] Then, parameters such as printing speed, infill density, and printing support are set, and the 3D model is adjusted to a suitable position and angle to balance surface quality and molding efficiency. Finally, Gcode code files are generated.

[0103] The printing speed is adjusted to achieve variable speed printing. The inner layer of the bionic finger uses a higher printing speed, while the outer layer uses a lower printing speed. During the printing process, pre-made differentiated internal stresses are applied to different layers. Programmable grasping can be achieved by changing the printing speed gradient or selecting different differentiated printing speed areas.

[0104] Step 4: Using multi-material FDM manufacturing process, shape memory polymer is used as the main material to print the above Gcode file into shape, accurately realizing the layer-by-layer construction of the gripper structure. After forming, the support structure is removed and the surface is finished to finally obtain a smart gripper with complete structure and integrated functions.

[0105] The working principle of the programmable bionic intelligent gripper with electro-healing and visual feedback functions of this invention is as follows:

[0106] Taking the proximal segment 10 of the bionic finger as an example: its internal conductive network resistance is R, its mass is m, its specific heat capacity is c, the applied electrical excitation is U, the energizing time is t, and the artificial shaping angle when heated to above Tg is θ. s The bending angle after shape programming and electrical excitation is θ a The initial temperature of the gripper is T0, the temperature after energization is T1, the elastic modulus of the material at the initial temperature T0 is E0, the elastic modulus of the material at the temperature T1 after energization is E1, and the temperature coefficient of the material's modulus is k.

[0107] The deformation angle of the single finger joint of the gripper after applying shape-programmed electrical excitation is:

[0108] ;

[0109] The shape fixation rate of the gripper's single finger joint after applying shape programming electrical excitation is:

[0110] ;

[0111] The deformation rate of a single finger joint of the gripper after applying three-electric excitation:

[0112] ;

[0113] After a power-on time t, the energy obtained by the gripper is:

[0114] ;

[0115] After a power-on time t, the temperature rise of the gripper is:

[0116] ;

[0117] After an energizing time t, the elastic modulus of the gripper is:

[0118] ;

[0119] The application scenarios of the bionic intelligent gripper of this invention are as follows:

[0120] (1) Intelligent grasping:

[0121] The flat, hand-shaped base structure is brought close to the target object, and a third electrical excitation is applied to activate the pre-prepared differentiated internal stresses at different levels, so that the molecular chain segments of the SMP can resume movement to complete the function of grasping the object.

[0122] Application scenarios of intelligent grasping: The programmable bionic 4D printed intelligent grasper with electro-healing and visual feedback functions described in this invention is particularly suitable for scenarios with high requirements for operational precision and adaptability, based on its flexible envelope, high integration and lightweight characteristics, such as precision electronic assembly, grasping of minimally invasive medical devices, space debris recovery or on-orbit maintenance. It can achieve non-destructive and reliable grasping of fragile, irregular and lightweight target objects.

[0123] (2) Repair of electrical damage:

[0124] The gripper is prone to damage when grasping sharp or rough objects or when used repeatedly. A first electrical excitation (damage repair electrical excitation) can be applied to the damaged finger units. By using Joule heating to bring the shape memory polymer to its glass transition temperature, its shape memory effect is activated, thereby achieving in-situ, active damage repair.

[0125] Application scenarios of electro-induced damage repair: By real-time monitoring of the gripper's status or periodic manual inspection, microcracks or surface wear, excessive bending or twisting of the finger joints can be detected in a timely manner. Subsequently, an electro-induced damage repair mechanism can be triggered by applying an initial electrical excitation, allowing the material to be repaired in situ before the gripping performance completely fails. This effectively maintains the structural integrity and functional reliability of the gripper, extending its service life and working cycle.

[0126] (3) State perception and visual feedback:

[0127] By monitoring the stress on the gripper, its working mode, and damage warnings, a second electrical excitation (status display electrical excitation) can be applied to make the temperature of the thermochromic PLA reach the color change threshold to change the material color, thus realizing the visualization of the system status.

[0128] Applications of status awareness and visual feedback: For example, in human-machine collaborative work units, changes in gripper color, such as green for successful gripping, yellow for moderate load, and red for overload or damage, provide operators with intuitive status feedback. Or, predictive maintenance of gripper systems: when the gripper is accidentally damaged, the color-changing material in the damaged area continues to display color under a second electrical excitation, providing maintenance personnel with intuitive damage location or indication of the degree of damage.

[0129] (4) Programmable selective drive:

[0130] Based on the design of conductive contacts, the proximal, middle and distal phalanges of each finger can be independently and precisely deformed by applying a third point excitation (driving electrical excitation), so as to complete flexible and adjustable grasping actions and program the grasping posture in real time.

[0131] Applications of programmable selective actuation: When grasping irregular target objects, selective actuation of independent phalanges and the efficient enveloping mechanism of the toe can achieve efficient and stable grasping. Or, when grasping continuously moving target objects, the grasping posture of the phalange units can be dynamically adjusted according to the object's movement during the grasping phase to achieve adaptive and stable grasping.

[0132] (5) Adaptive stiffness dynamic adjustment:

[0133] By applying a fourth electrical excitation (regulating the SMP modulus electrical excitation), the softness and hardness of the SMP are actively controlled. It is in a softer state when approaching the object to prevent collision, switches to a high-rigidity state during the grasping phase to provide a stable grip, and returns to a softer state during the release phase to achieve a gentle release.

[0134] Applications of adaptive stiffness dynamic adjustment include: when rapidly grasping irregularly shaped or fragile targets, it is necessary to avoid damage during the grasping process while ensuring stability. Alternatively, in space environments, such as capturing targets or performing on-orbit maintenance, gentle capture is essential to prevent collisions and debris, while maintaining stiffness during the grasping phase for subsequent rigid docking or operations.

[0135] In summary, the described programmable biomimetic 4D-printed intelligent gripper with electrocautery and visual feedback functions is integrally molded from a polymer material using a multi-material 4D printing process. It incorporates an internal conductive network and an external shape memory polymer. The gripper offers advantages such as electrocautery repair, visual feedback, programmable actuation, high integration, and lightweight design.

Claims

1. A programmable biomimetic 4D printed intelligent gripper with electro-healing and visual feedback functions, characterized in that: The gripper is modeled after the efficient anti-digital envelopment mechanism and color-changing characteristics of the arboreal chameleon's foot, and incorporates the phalangeal structure of primates. It comprises 2n evenly distributed bionic fingers, forming n groups of cooperative anti-digital envelopment groups. The bionic finger comprises a proximal segment (10), joint one (11), middle segment (12), joint two (13), and distal segment (14) connected in sequence. The proximal segment (10) is the longest, followed by the middle segment (12), and the distal segment (14) is the shortest. All three are active deformation units. When a third electrical excitation is applied to the conductive contact I (104) and conductive contact II (105) on the proximal segment (10), the proximal segment (10) bends; When a third electrical excitation is applied to the conductive contacts III (121) and IV (122) on the middle section (12), the middle section (12) bends; When a third electrical excitation is applied to the conductive contact V (141) and conductive contact VI (142) on the distal segment (14), the distal segment (14) bends; When a third electrical excitation is applied to the conductive contact I (104) and the conductive contact VI (142), the bionic finger bends as a whole; The gripper is integrally formed using additive manufacturing technology; the proximal segment (10), middle segment (12), distal segment (14) and joint of the bionic finger are all three-layer composite structures; The near section (10), middle section (12), and far section (14) are all composed of a thermochromic PLA outer layer (101), a conductive PLA network (102), and a thermochromic PLA inner layer (103); Each joint is composed of a joint TPU 85A outer layer (111), a conductive PLA network (102), and a joint TPU 85A inner layer (112); When the conductive PLA network 102 is energized, it generates Joule heat to achieve one or more of the following functions: as an electrical excitation for pre-grab shape programming, as a first electrical excitation (damage repair electrical excitation), as a second electrical excitation (status display electrical excitation), as a third electrical excitation (drive electrical excitation), and as a fourth electrical excitation (modulus control electrical excitation).

2. The programmable biomimetic 4D printed smart gripper with electrocautery and visual feedback functions according to claim 1, characterized in that: The bionic finger has bionic scale structures (143) on the inner sides of the proximal segment (10), middle segment (12), and distal segment (14) to increase the interface friction coefficient.

3. The programmable biomimetic 4D printed intelligent gripper with electrocautery and visual feedback functions according to claim 2, characterized in that: The gripper is modeled after the efficient enveloping mechanism and color-changing characteristics of the arboreal chameleon's foot, combined with the phalangeal structure of primates.

4. A programmable biomimetic 4D printed smart gripper with electro-healing and visual feedback functions according to claim 1, 2, or 3, characterized in that: The conductive PLA network (102) in the three-layer composite structure is composed of graphene and basic PLA material, giving the composite material the dual functions of shape memory and conductivity.

5. A programmable biomimetic 4D printed intelligent gripper with electrocautery and visual feedback functions according to claim 4, characterized in that: The proximal segment (10), middle segment (12), distal segment (14) and joint of the bionic finger are all three-layer composite structures with a thickness ratio of 3:2:1 from the inner layer to the outer layer.

6. A programmable biomimetic 4D printed intelligent gripper with electrocautery and visual feedback functions according to claim 5, characterized in that: The conductive PLA network (102) is controlled independently by partitions and has multiple conductive contacts that apply electrical excitation; a groove is provided at the position of the temperature-changing PLA outer layer (101) corresponding to the conductive contact.

7. A programmable bionic intelligent gripper with electrocautery and visual feedback functions according to claim 6, characterized in that: Taking the proximal segment (10) of the bionic finger as an example: its internal conductive network resistance is R, its mass is m, its specific heat capacity is c, its applied electrical excitation is U, its energizing time is t, and its artificial shaping angle when heated to above Tg is θ. s The bending angle after shape programming and electrical excitation is θ a The initial temperature of the gripper is T0, the temperature after energization is T1, the elastic modulus of the material at the initial temperature T0 is E0, the elastic modulus of the material at the temperature T1 after energization is E1, and the temperature coefficient of the material's modulus is k. The deformation angle of the single finger joint of the gripper after applying shape-programmed electrical excitation is: ； The shape fixation rate of the gripper's single finger joint after applying shape programming electrical excitation is: ； The deformation rate of a single finger joint of the gripper after applying three-electric excitation: ； After a power-on time t, the energy obtained by the gripper is: ； After a power-on time t, the temperature rise of the gripper is: ； After an energizing time t, the elastic modulus of the gripper is: 。 8. A method for using a programmable bionic intelligent gripper with electrocautery and visual feedback functions, characterized in that: The programmable biomimetic 4D printed smart gripper with electro-healing and visual feedback functions as described in claim 6 is used as follows: 1) Damage Repair Apply a first electrical excitation to the contacts near the area requiring damage repair. Through the electrical excitation, the conductive PLA network (102) generates Joule heating, heating the thermochromic PLA outer layer (101) and thermochromic PLA inner layer (102) to above their glass transition temperature Tg, activating the shape memory effect of the material, and repairing cracks and structural failures. 2) Status display A second electrical excitation is applied to the bionic finger that requires status display, and the status of the bionic finger is visualized by changing the color of the thermochromic material; the thermochromic PLA outer layer (101) and thermochromic PLA inner layer (103) are reversible thermochromic materials with color-changing function triggered by heat. 3) Crawler driver When it is necessary to grasp an object, a third electrical excitation is applied to the bionic finger, and independent and precise deformation control is applied to the proximal segment (10), middle segment (12), and distal segment (14) of each finger. This activates the application of pre-made differentiated internal stress at different levels, allowing the molecular chain segments of the SMP to resume movement, complete the flexible and adjustable grasping action, and program the grasping posture in real time. 4) Modulus control When stiffness adaptive adjustment is required, a fourth electrical excitation is applied to the bionic finger to actively regulate the stiffness of the SMP, so that the gripper has active flexibility similar to biological muscles. It is in a softer state when approaching the object to prevent collisions, and switches to a high-rigidity state during the grasping phase to provide a stable grip.

9. A method for manufacturing a programmable bionic intelligent gripper with electro-healing and visual feedback functions, characterized in that: The specific manufacturing steps of the programmable bionic intelligent gripper with electro-healing and visual feedback functions as described in claim 6 are as follows: Step 1: The gripper is made of materials according to the functional zoning requirements. The outer layer of the knuckle is made of thermochromic PLA, the outer layer of the joint is made of TPU 85A, and the interior is made of conductive PLA forming a conductive network. Step 2: The gripper model is established. The finger joint model of the gripper is designed and built using the 3D modeling software SolidWorks. The joints are designed using the generative shape design module and part design module in the 3D modeling software CATIA. The three-layer structure of the model is inserted and combined in different geometric forms to facilitate the subsequent assignment of material properties. Step 3: After the 3D model is built, it is imported into the slicing software for processing: First, the material properties are assigned to each layer. The innermost and outermost layers of the grasping finger joint structure are made of thermochromic PLA material, the innermost and outermost layers of the joint are made of TPU 85A material, and the overall internal conductive network is made of conductive PLA. Then, parameters such as printing speed, infill density, and printing support are set, and the 3D model is adjusted to a suitable position and angle to balance surface quality and molding efficiency. Finally, Gcode code files are generated. The printing speed is adjusted to achieve variable speed printing; the inner layer of the bionic finger uses a higher printing speed, while the outer layer uses a lower printing speed. During the printing process, pre-made differentiated internal stresses are applied to different layers, and programmable gripping is achieved by changing the printing speed gradient or selecting different differentiated printing speed areas; Step 4: Using multi-material FDM manufacturing process, shape memory polymer is used as the main material to print the above Gcode file into shape, accurately realizing the layer-by-layer construction of the gripper structure. After forming, the support structure is removed and the surface is finished to finally obtain a smart gripper with complete structure and integrated functions.

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