A robot bionic forehead wrinkle forming device and control method based on under-actuation and deformation guidance

Abstract

The application provides a robot bionic forehead wrinkle forming device and control method based on underactuation and deformation guidance, which comprises the following steps: a forehead bionic elastic body module is fixed on a forehead bearing structure of a robot; a distal end action part of a traction mechanism is connected with a corresponding target area on the forehead bionic elastic body module; a deformation guidance constraint structure is fixed on the forehead bearing structure; a slider of the deformation guidance constraint structure is connected with the forehead bionic elastic body module so as to guide the formation of forehead wrinkles; a driving module power output end is connected with a driving part at the proximal end of the traction mechanism; and the driving module applies a backward traction force to the target area through the traction mechanism. The application also discloses a robot bionic forehead wrinkle forming control method. Through the method of'mechanical constraint guiding deformation', the application realizes high-imitative forehead expression simulation by using a simple underactuation structure, and solves the technical problems of traditional 'component driving' scheme, such as stiff expression and uncontrollable wrinkles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bionic robots, in particular to a robot bionic forehead wrinkle forming device and control method based on under-actuation and deformation guidance, which is used for simulating the physiological process of dynamic wrinkle generation of human forehead skin when facial expression changes. BACKGROUND

[0002] In the field of bionic robot facial expression simulation, forehead wrinkles (such as "elevated forehead wrinkles") are key visual features to express complex emotions such as surprise, doubt, thinking, concentration, etc. These wrinkles are not static notches, but dynamic and nonlinear deformations of skin soft tissue under the contraction of underlying muscles (such as forehead muscles) and the constraint of upper skeletal structures.

[0003] Existing bionic robot technology has obvious deficiencies in forehead wrinkle simulation. The mainstream solutions can be summarized into two categories:

[0004] 1. Static preset method: pre-sculpt or shape fixed wrinkles on bionic skin material. This method cannot achieve dynamic generation and disappearance of wrinkles at all, and the expression is distorted and rigid.

[0005] 2. Passive following method: some existing technologies use the movement of a rigid or semi-rigid "proxy component" to drive the displacement of the flexible skin covered on it, thereby passively generating some following wrinkles. The essence of this method is "component displacement driving", which has the following defects:

[0006] Deformation mechanism distortion: human wrinkles are structured buckling of the skin itself under active compression and constraint, not caused by the pressure of a hard sheet.

[0007] Wrinkle morphology uncontrollable: the generated skin wrinkles are the result of passive response of the material, which is random and cannot accurately control the direction, depth, number and dynamic process of the wrinkles, resulting in rigid and unnatural expression.

[0008] System complexity tendency: to simulate more natural wrinkles, it is often necessary to increase the driving points or use more complex multi-degree-of-freedom mechanisms, which contradicts the design requirements of compact head space and limited driving units of robots.

[0009] Therefore, the existing technology lacks a solution that can actively guide and actively constrain the forehead skin to produce dynamic and realistic wrinkles from the essence of biomechanics. A new technology is needed to shift the design focus from "how to drive a component" to "how to guide a piece of material to have constrained and controlled deformation". SUMMARY

[0010] The purpose of the present application is to overcome the fundamental defects of the existing "component-driven", and to propose a completely new "active deformation guiding" technical solution, aiming to solve the technical problems of rigid driving or simple pull line driving of bionic robots, which leads to stiff forehead expression movement, uncontrollable wrinkle generation, and poor simulation degree, thereby significantly improving the naturalness and realism of human-computer interaction.

[0011] To achieve the above-mentioned purpose, the first aspect of the present application provides a robot bionic forehead wrinkle forming device based on under-actuation and deformation guiding. The core idea is to abandon the conventional method of indirectly affecting the skin by driving independent rigid components, and instead design and introduce a "deformation guiding constraint structure" fixed on the bearing structure. As a "mechanical guide rail", when the driving module applies a basic traction force to the bionic skin through the traction mechanism, the deformation guiding constraint structure actively intervenes and directs the flow and deformation of the skin material, thereby converting simple linear input force into complex skin wrinkle output consistent with biomechanics.

[0012] Specifically, the device comprises:

[0013] a forehead bionic elastomer module, which is fixedly fitted on the bearing structure of the robot forehead;

[0014] a traction mechanism, the distal end of which is connected to the predetermined target area on the forehead bionic elastomer module;

[0015] a deformation guiding constraint structure, which is fixedly arranged on the forehead bearing structure. The deformation guiding constraint structure is connected to the forehead bionic elastomer module through the slider, and the deformation guiding constraint structure guides the skin layer of the forehead bionic elastomer module to produce one or more transverse forehead wrinkles during deformation movement;

[0016] a driving module, the power output end of which is connected to the proximal end driving part of the traction mechanism; the driving module is configured to apply a traction force mainly in the backward direction to the target area through the traction mechanism; at the same time, the fixed deformation guiding constraint structure produces specific geometric interference and motion constraint to the forehead bionic elastomer module which tries to move under traction, forcing the skin material of the module to occur directed and structured flexure wrinkles at the constraint site, thereby actively and predictably forming one or more realistic transverse forehead skin wrinkles.

[0017] Further, the deformation guiding constraint structure comprises at least one longitudinal clamping slot fixed on the forehead bearing structure, and a slider arranged inside the forehead bionic elastomer module and slidingly matched with the longitudinal clamping slot. This design constitutes a constraint mechanism:

[0018] Further, the traction mechanism is connected to the target area at a preset spatial inclination angle, so that the traction force is decomposed into an upward vertical component (for realizing possible eyebrow-related movements) and a backward horizontal component (for generating skin compression, the core driving force for forming wrinkles). The inclination angle can be designed according to the expression requirements, for example, its projection on the horizontal plane has an angle of 15° to 40° with the sagittal plane, and an upward angle of 15° to 75° with respect to the horizontal plane.

[0019] Further, the traction mechanism can be provided in two, independently acting on the left and right forehead areas respectively. By configuring the same or different traction parameters and deformation guiding constraints for the two, symmetric or asymmetric wrinkle patterns can be realized, greatly enriching the delicate expression performance.

[0020] Further, the forehead biomimetic elastomer module adopts a biomimetic layered structure, including a strain layer and a skin layer from inside to outside. The strain layer is an elastic matrix embedded with a biomimetic reinforced fiber network, which is distributed radially to simulate the mechanical properties of real skin and work cooperatively with the deformation guiding constraint structure, ensuring smooth, realistic and repeatable deformation.

[0021] Further, the driving module includes a controller, a motor and a transmission mechanism, forming a closed-loop or open-loop control system for accurately driving the physical execution process according to the target expression parameters.

[0022] According to a second aspect of the present application, a robot biomimetic forehead wrinkle formation control method based on under-actuation and deformation guiding is provided, applied to the foregoing device. The core of this method is to explicitly include the geometric and mechanical parameters of the deformation guiding constraint structure in the control model, thereby establishing an accurate mapping from the "target wrinkle pattern" to the "driving mechanism instruction". The method includes:

[0023] S1: receiving an expression instruction and analyzing to obtain the desired forehead wrinkle pattern parameters (such as depth, number, symmetry);

[0024] S2: converting the target pattern parameters into the control parameters (such as motor stroke, speed) of the driving module according to the pre-established control mapping model containing the specific parameters of the deformation guiding constraint structure and the nonlinear properties of the biomimetic elastomer material;

[0025] S3: controlling the driving module to drive the traction mechanism to perform corresponding actions;

[0026] S4: under the synergistic action of traction force and deformation guiding constraint structure, the forehead biomimetic elastomer module is accurately guided to produce dynamic transverse wrinkles consistent with expectations;

[0027] S5: After the expression is completed, the control driving module reverses the release force, and the forehead biomimetic elastomer module is automatically reset by relying on the material elasticity and the restoring force of the internal fiber network, and the wrinkles are smoothed and disappear.

[0028] The beneficial effects of the present application are to realize the innovative breakthrough of the technical principles and design paradigms:

[0029] 1. Principle innovation: from traditional "driving component displacement" to "guiding material deformation". Through fixed deformation guiding constraint structure, the final form of skin wrinkles is directly planned and determined, which is more close to the natural process of biological muscle and / or skin wrinkles caused by skeletal constraints.

[0030] 2. Structural innovation and under-actuation advantage: using a sophisticated mechanical constraint design, a single, simple driving input (linear traction) is decoupled and reconstructed into a complex two-dimensional deformation output (up + transverse wrinkles). With few driving sources (under-actuation), high-dimensional expression simulation is realized, the system structure is greatly simplified, the reliability is improved, and the cost is reduced.

[0031] 3. High and controllable simulation: it can dynamically simulate the continuous and controllable change process of wrinkles from nothing to something, from shallow to deep, and the generated wrinkle form is accurate, natural, and consistent with the anatomical characteristics. Through parameterized design, a variety of forehead expressions can be programmed.

[0032] 4. Provide a new technical path: the "fixed constraint guided deformation" solution proposed in the present application opens up a new and creative way for biomimetic robot facial expression design, especially the simulation of skin texture and dynamic wrinkles, which is different from all existing technical routes. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A structure schematic diagram of a robot biomimetic forehead wrinkle forming device based on under-actuation and deformation guidance according to an embodiment of the present application;

[0034] Figure 2 A biomimetic elastomer module structure schematic diagram of a robot biomimetic forehead wrinkle forming device based on under-actuation and deformation guidance according to an embodiment of the present application;

[0035] Figure 3 A single driving module structure schematic diagram of a robot biomimetic forehead wrinkle forming device according to the present application;

[0036] Figure 4 A space inclination angle schematic diagram of a traction mechanism according to the present application (the number 7 in the figure is a preset inclination line, and the rectangular line is a simulated three-dimensional space);

[0037] Figure 5A structure diagram of a deformation guiding constraint structure (two deformation guiding constraint structures) of a robot bionic forehead wrinkle forming device based on under-actuation and deformation guiding according to an embodiment of the present application;

[0038] Figure 6 A structure diagram of a deformation guiding constraint structure (one deformation guiding constraint structure) of a robot bionic forehead wrinkle forming device based on under-actuation and deformation guiding according to an embodiment of the present application;

[0039] Figure 7 A control method logic flow chart of a robot bionic forehead wrinkle forming based on under-actuation and deformation guiding according to an embodiment of the present application;

[0040] Mark No. 1-forehead bionic elastomer module; 12-strain layer; 13-skin layer; 2-forehead bearing structure; 3-pulling mechanism; 31-acting part; 32-driving part; 33-pulling rope; 34-guiding channel assembly; 4-forehead target area; 41-forehead outer target area; 42-forehead middle target area; 5-driving module; 51-controller; 52-motor; 53-transmission mechanism; 6-deformation guiding constraint structure; 61-clamp slot; 62-sliding block; 7-preset inclined line. DETAILED DESCRIPTION

[0041] The technical solutions in the present application will be described in detail below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0042] It should be noted that the terms "include" and "have" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units need not be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0043] In the present application, the terms "upper", "front", "rear", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0044] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0045] In addition, the terms "mounting", "provided with", "connection" should be understood broadly. For example, it can be fixed connection, detachable connection, or integral structure; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific situation.

[0046] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the protection scope of the present application, and the present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0047] Embodiment 1

[0048] As shown in Figure 1 and Figure 3 The present embodiment provides a robot bionic forehead wrinkle forming device based on underactuation and deformation guidance, which comprises the following core parts: a forehead bionic elastomer module 1, a traction mechanism 3, a deformation guidance constraint structure 6 and a driving module 5. The forehead bionic elastomer module 1 is fixedly fitted on the forehead bearing structure 2 above the robot eyebrow arch. The forehead bearing structure 2 matches the shape of the forehead of a living being, such as the arc-shaped forehead of a human. The slider of the deformation guidance constraint structure is connected with the forehead bionic elastomer module. When the forehead bionic elastomer module deforms, the deformation guidance constraint structure drives the skin layer of the forehead bionic elastomer module to produce one or more transverse forehead wrinkles.

[0049] The forehead bionic elastomer module 1 can be made of bionic silica gel material, and contains a strain layer with a bionic reinforced fiber network embedded therein.

[0050] The shape guiding constraint structure comprises at least one longitudinal clamping slot fixed on the forehead bearing structure, and a sliding block arranged inside the forehead biomimetic elastomer module and in sliding fit with the longitudinal clamping slot. This design constitutes a constraint mechanism.

[0051] Longitudinal sliding freedom: allows the module as a whole to move in the direction of the clamping slot (i.e. approximately perpendicular to the direction of the expected wrinkles), realizing the directional displacement of the target area of the forehead.

[0052] Lateral rigid constraint: the side wall of the clamping slot forms a strong lateral (i.e. parallel to the direction of the expected wrinkles) displacement limit for the sliding block.

[0053] Active wrinkle forming mechanism: when the traction force from the rear drives the module, the module material is forced to compressively destabilize in the lateral direction in the area between adjacent sliding blocks under the constraint of having longitudinal sliding freedom but being forbidden to expand laterally, thus forming clear lateral wrinkles by rising upwards. The arrangement of the longitudinal clamping slots directly presets the direction, position and number of the wrinkles.

[0054] As shown in Figure 1 and Figure 3 The acting part 31 of the distal end of the traction mechanism 3 is connected with the corresponding forehead target area 4 (including the eyebrow linkage area) on the forehead biomimetic elastomer module 1. The forehead target area 4 includes the forehead middle target area 42 and the forehead lateral target area 41.

[0055] The power output end of the driving module 5 is connected with the driving part 32 of the proximal end of the traction mechanism 3. The driving module 5 drives the traction mechanism 3 to tighten or release according to the control instruction, driving the forehead target area 4 to produce a composite deformation upward and rearward, thus forming lateral dynamic wrinkles in the forehead area, and naturally driving the eyebrows to lift up, realizing the high-realistic forehead expression and eyebrow linkage effect.

[0056] The traction mechanism 3 comprises a traction rope 33. The acting part 31 of the distal end of the traction rope 33 is connected with the forehead target area 4. The driving part 32 of the proximal end of the traction rope 33 is connected with the power output end of the driving module 5. The acting part 31 of the distal end of the traction rope 33 is connected with the forehead target area 4.

[0057] The traction rope 33 can be selected from one or a combination of high-strength fiber rope, ultra-fine steel wire rope or flexible webbing. These ropes have the characteristics of high strength, low elongation and bending fatigue resistance. It is best to use high-strength fiber rope because such rope has smaller friction and the sound produced by movement is particularly small.

[0058] The traction mechanism 3 also comprises a guide channel assembly 34, through which the traction rope 33 passes, and which is used to constrain the movement path of the traction rope 33. The guide channel assembly 34 is preferably composed of some sleeves or rails with small friction coefficients, which are used to constrain the movement path of the traction rope 33, ensure that the pulling force is transmitted in a predetermined direction, reduce energy loss and movement interference. At the same time, it can also provide the functions of guiding and limiting. The guide channel assembly 34 is fixed inside the head, and the driving module 5 is also fixedly installed inside the head.

[0059] The traction mechanism 3 is two, which are respectively a first traction mechanism 3 and a second traction mechanism 3, and the action parts 31 at the distal ends of the two traction mechanisms 3 are respectively connected to the front outer target area 41 and the front middle target area 42, so that the driving module 5 can independently control the two traction mechanisms 3, thereby realizing symmetrical or asymmetrical front wrinkle patterns and naturally driving the corresponding movement of the eyebrow part, and enriching the expression performance. That is, the first traction rope 33 of the first traction mechanism 3 and the second traction rope 33 of the second traction mechanism 3 are respectively connected to the front outer target area 41 and the front middle target area 42. By adopting two traction ropes 33 through the tightening and / or releasing working process, the shape of the front wrinkle and the movement trajectory of the eyebrow part can be effectively controlled.

[0060] The distal end action part 31 of the traction mechanism 3 is connected to the strain layer of the front forehead biomimetic elastomer module by vulcanization or adhesion.

[0061] The deformation guiding and constraining structure 6 is fixedly arranged on the front forehead bearing structure 2. In the preferred embodiment, the deformation guiding and constraining structure 6 is composed of a longitudinal clamping groove 61 fixed on the front forehead bearing structure 2 and a sliding block 62 which is in sliding cooperation with the clamping groove 61 and is connected to the strain layer of the front forehead biomimetic elastomer module 1. The core function of this structure is to allow the sliding block 62 and the connected elastomer material to smoothly slide along the longitudinal direction of the clamping groove (i.e. perpendicular to the expected wrinkle direction), while strictly limiting its transverse displacement expansion (i.e. parallel to the wrinkle direction) through the side wall of the clamping groove.

[0062] As shown in Figure 3 The driving module 5 comprises a controller 51, a motor 52 and a transmission mechanism 53; the controller 51 is electrically connected to the motor 52 for controlling the operation of the motor 52, the motor 52 is connected to the transmission mechanism 53 to drive the transmission mechanism 53 to rotate, and the controller 51 is used to control the motor 52 to drive the traction mechanism 3 to move through the transmission mechanism 53 according to the target expression and wrinkle parameters. The motor 52 adopts a micro motor 52 (such as a servo motor 52 or a stepping motor 52), and the transmission mechanism 53 can adopt a reducer and a transmission shaft in cooperation, or a winding wheel.

[0063] The application can realize the dynamic generation and disappearance of transverse forehead wrinkles, and synchronously drive the natural movement of the eyebrow. Two groups of driving modules 5 can be arranged to control the left and right forehead regions respectively, to realize symmetrical or asymmetrical wrinkles and eyebrow expressions, with simple structure, high fidelity and flexible control.

[0064] Embodiment 2

[0065] The other parts are the same as those in Embodiment 1, and the difference from Embodiment 1 is that the forehead biomimetic elastomer module 1 comprises a strain layer 12 and a skin layer 13 from inside to outside; the strain layer 12 is an elastic matrix embedded with a biomimetic reinforced fiber network; the strain layer 12 is fixedly attached to the forehead bearing structure 2; the forehead biomimetic elastomer module 1 covers the forehead and eyebrow regions. The fiber network is distributed in a radial manner, and the fiber density of the biomimetic reinforced fiber network decreases gradually from the region above the eyebrow arch to the hairline, to simulate the mechanical properties of the forehead skin and the wrinkle formation trend.

[0066] The outer surface of the skin layer 13 has a biomimetic skin texture, which should have a human skin texture when applied to the human body of a biomimetic robot. The skin layer 13 is made of medical-grade silicone with skin color pigment and surface texture. The biomimetic reinforced fiber network in the strain layer 12 is a network of aramid fibers radiating outward, to guide the forehead skin to bend and form wrinkles along the preset direction when subjected to tension. The silicone matrix in the strain layer 12 is added with a softener, and its elastic modulus is designed by gradient, which is harder near the eyebrow arch and gradually softer upward.

[0067] The distal end acting part 31 of the traction mechanism 3 is connected with the strain layer 12 of the forehead biomimetic elastomer module 1 by vulcanization or bonding.

[0068] Embodiment 3

[0069] The other parts are the same as those in Embodiment 1 or Embodiment 2, and the difference is that, to realize natural forehead wrinkle generation and eyebrow linkage, the traction mechanism 3 is not pulled vertically upward, but is connected to the corresponding target region on the forehead biomimetic elastomer module 1 at a preset inclined angle. The driving module 5 drives the traction mechanism 3 to pull, so that the traction mechanism 3 exerts a pulling force with a rear upward spatial direction on the forehead target region 4 along the preset inclined angle, to drive the forehead target region to produce a composite deformation of rear stretching and upward pulling.

[0070] As shown in Figure 4 , the preset inclined angle is a spatial angle, and the reference sign 7 is a preset inclined line, i.e. the movement path direction of the traction rope 33. The included angle α between the projection of the preset inclined angle on the horizontal plane and the sagittal plane is 15°, and the preset inclined angle is an elevation angle formed by looking upward from the horizontal plane, and the elevation angle β is 30°.

[0071] Through this design, when the driving module 5 pulls upward and backward, a spatial pulling force is applied to the forehead target area 4, which can be decomposed into a backward component (making the skin tense backward and guided to form horizontal forehead wrinkles) and an upward component (naturally lifting the eyebrows), thereby synchronously achieving "forehead wrinkle formation" and "eyebrow expression linkage". After releasing the traction, the forehead biomimetic elastic body module 1 relies on its own elastic reset, and the wrinkles disappear smoothly, and the eyebrows return to the original position.

[0072] This "inclined traction" mechanism accurately reproduces the oblique backward and upward resultant force generated by the frontal muscle contraction, synchronously achieving the two core visual features of "horizontal forehead wrinkle generation" and "eyebrow natural lifting", and the expression is natural and the mechanism is realistic.

[0073] Embodiment 4

[0074] The difference between embodiment 3 and embodiment 4 is that the angle α between the projection of the preset inclined angle on the horizontal plane and the sagittal plane is 30°, and the preset inclined angle is an upward-looking angle formed by looking upward from the horizontal plane, and the upward-looking angle β is 60°.

[0075] Embodiment 5

[0076] According to another aspect of the present application, a robot forehead wrinkle and eyebrow linkage expression control method is also provided, which is applied to a biomimetic simulation device, such as Figure 7 As shown, the method comprises the steps of:

[0077] S1: receiving an expression instruction and analyzing to obtain the deformation parameters of the forehead target area wrinkle;

[0078] The controller 51 receives an expression instruction (such as "slight surprise", "strong doubt", etc.) from the robot main control system, the controller 51 analyzes the instruction, calls the internal preset expression parameter library, and obtains the specific deformation parameters required for the current expression, including the expected depth, distribution of forehead wrinkles, and the related movement amplitude of the eyebrows.

[0079] S2: converting the deformation parameters into target strokes of the corresponding traction mechanism 3 according to the kinematic mapping model;

[0080] The controller 51 converts the deformation parameters of the forehead target area into the target strokes required for driving the corresponding traction mechanism 3 (the first traction mechanism 3 and the second traction mechanism 3) according to the pre-stored kinematic mapping model (S1, S2). The mapping model considers factors such as the geometric layout of the traction mechanism 3, the material mechanics properties of the elastic body module, the parameters of the deformation guiding and restraining structure 6, and the transmission relationship of the driving module, and establishes a mathematical relationship between the target deformation and the target stroke.

[0081] S3: Control the driving module 5 to drive each traction mechanism 3 to perform a traction action to complete the target stroke thereof;

[0082] The controller 51 generates a control signal according to the calculated target stroke and speed curve, drives the motor 52 to operate, and the motor 52 accurately pulls each traction mechanism 3 through the transmission mechanism 53, so that each traction mechanism 3 completes the target stroke thereof.

[0083] S4: Through the synergistic action of the inclined traction of the traction mechanism 3 and the deformation guiding and restraining structure 6, the target area of the forehead biomimetic elastomer module 1 generates an expected transverse forehead wrinkle and a composite biomimetic deformation. Specifically, the traction force provides the original driving force (stretching) for forming the wrinkle, and the deformation guiding and restraining structure 6 defines and limits the accurate position and direction of the skin material releasing strain and forming the wrinkle, like a 'track'.

[0084] Under the synergistic action of the inclined traction of the traction mechanism 3 and the deformation guiding and restraining structure 6, the target area on the forehead biomimetic elastomer module 1 is subjected to a specific spatial direction of the pulling force and geometric constraint, the skin material is guided to occur transverse flexure, form natural forehead wrinkles, and synchronously drive the eyebrow to produce associated lifting movement, complete a highly realistic forehead expression.

[0085] S5: After the expression is completed, the driving module 5 reverses the pulling force, and the forehead biomimetic elastomer module 1 resets itself by relying on its elasticity.

[0086] The kinematic mapping model is established through a calibration experiment and contains the material nonlinear mechanical properties of the forehead biomimetic elastomer module 1 and the geometric parameters of the deformation guiding and restraining structure 6.

[0087] In the embodiment of the application, the specific operation process is as follows: the controller 51 sends a signal to control the rotation of the two motors 52, the rotation of the motor 52 drives the rotation of the transmission mechanism 53 (such as the rotation of the winding wheel), so that the forehead target area is pulled to move backward and upward, a dynamic transverse wrinkle is formed on the forehead, and the eyebrow is moved. The controller 51 receives an expression instruction from an upper computer (a robot main control system), and the controller 51 stores a "forehead expression parameter" mapping table. When asymmetric wrinkles and eyebrow linkage need to be simulated, differential control can be performed on the two traction mechanisms to form a natural and delicate expression effect.

[0088] In the embodiments of the application, the biomimetic elastomer structure, the spatial inclined traction layout, the deformation guiding and restraining structure, and the independent partition control are adopted, the highly realistic forehead expression of the robot in the wrinkle form, the dynamic process, and the eyebrow linkage is realized, and the naturalness and the reality of human-computer interaction are significantly improved.

[0089] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A robotically-enabled forehead wrinkle formation device based on under-actuation and morphogenesis guidance, comprising: The application relates to a forehead biomimetic elastic body module (1) which is fixedly fitted on a forehead bearing structure (2) of a robot, a traction mechanism (3) which is connected with a corresponding target area on the forehead biomimetic elastic body module (1), a deformation guiding and restraining structure (6) which is fixedly arranged on the forehead bearing structure (2) and connected with the forehead biomimetic elastic body module, a driving module (5) which is connected with a driving part (32) of a proximal end of the traction mechanism (3) and applies a rearward traction force to the target area through the traction mechanism (3), wherein the deformation guiding and restraining structure (6) comprises at least one longitudinal clamping groove (61) which is fixed on the forehead bearing structure (2) and a plurality of sliding blocks (62) which are slidingly matched with the clamping groove (61), so that the sliding blocks slide along the longitudinal direction of the clamping groove and the transverse displacement of the sliding blocks is restrained by the clamping groove wall, the traction mechanism (3) further comprises a traction rope (33) and a guide channel assembly (34), the traction rope (33) is arranged in the channel of the guide channel assembly (34) and is used for restraining the movement path of the traction rope, the traction mechanism (3) is connected with the target area at a preset spatial inclination angle, so that the traction force has a vertical upward component and a horizontal rearward component. The projection of the preset spatial inclination angle on a horizontal plane forms an angle of 15-40 degrees with a sagittal plane, and the upward angle relative to the horizontal plane is 15-75 degrees. The traction mechanism (3) is provided with two traction mechanisms which are independently connected with the target areas on the left and right sides respectively, and the driving module (5) can independently or cooperatively control the two traction mechanisms. The forehead biomimetic elastic body module (1) comprises a strain layer (12) and a skin layer (13) from inside to outside, the strain layer (12) is an elastic matrix in which a biomimetic reinforcing fiber network is embedded, and the fiber network is distributed in a radial manner. The driving module (5) comprises a controller (51), a motor (52) and a transmission mechanism (53), the controller (51) is used for controlling the motor (52) to drive the traction mechanism (3) through the transmission mechanism (53) according to target wrinkle parameters. The application further discloses a forehead biomimetic elastic body module control method comprising the following steps: S1: receiving an expression instruction and analyzing to obtain the shape parameters of target wrinkles; S2: converting the shape parameters into control parameters of the driving module according to a control mapping model which is pre-established and contains the geometric parameters of the deformation guiding and restraining structure (6) and the material characteristics of the forehead biomimetic elastic body module; 2. The bionic forehead wrinkle forming device according to claim 1, characterized in that, S3: controlling the driving module to drive the traction mechanism to perform a traction action.

3. The bionic forehead wrinkle forming device according to claim 1, characterized in that, ​ 4. The bionic forehead wrinkle forming device according to claim 1, characterized in that, ​ 5. The bionic forehead wrinkle forming device according to claim 1, characterized in that, ​ 6. A method for controlling the formation of a forehead wrinkle in a robot based on under-actuation and morphing guidance, applied to the device for forming a forehead wrinkle according to any one of claims 1 to 5, characterized in that, ​ ​ ​ ​ S4: under the cooperation of the traction force of the traction mechanism and the deformation guiding constraint structure, the skin layer of the forehead biomimetic elastic body module is guided to generate expected transverse forehead wrinkles; S5: after the expression is completed, the driving module is controlled to reverse and release the traction force, and the forehead biomimetic elastic body module resets relying on its own elasticity, and the wrinkles disappear.

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