Intelligent joint rehabilitation brace based on 4D printing and customizable force feedback and preparation method and system thereof

Abstract

The invention discloses a preparation method and system of an intelligent joint rehabilitation brace based on 4D printing and customizable force feedback, and the method comprises the steps: determining a structural form adaptive to 4D printing according to the structure of a joint part, and pre-determining structural parameters in the structural form and a mapping relation between key structural parameters and force feedback, the model is embedded into model design software, and key structure parameters of the model can be correspondingly adjusted according to the mapping relation and force feedback needed by rehabilitation to obtain a brace sheet model; a three-dimensional structure is formed through 4D printing, and the intelligent joint rehabilitation brace is obtained after adjustment. Compared with a traditional brace manufacturing technology, the manufactured intelligent hand brace is lower in cost and higher in manufacturing speed and can have the function of sensing the force feedback magnitude of a patient in real time.

Description

Technical Field

[0001] The present invention belongs to the field of medical rehabilitation equipment, and specifically relates to an intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback, and a preparation method and system thereof. Background Art

[0002] Various joints play a vital role in daily life. Taking the hand as an example, due to its structural complexity and fragility, the hand joints are extremely susceptible to injuries such as fractures, soft tissue contusions and muscle strains. These injuries can seriously affect patients' daily life and work ability. Therefore, rehabilitation of hand injuries is particularly important. Traditional hand rehabilitation usually relies on hand braces (orthosis) to provide support and rehabilitation. However, existing hand orthoses have many limitations. First, most orthoses lack dynamic force feedback adjustment capabilities and cannot be adjusted in real time according to the needs of the patient's rehabilitation process. Secondly, these devices are often designed based on statistical averages and fail to fully consider the differences in individual hand sizes, resulting in low patient compliance and affecting rehabilitation effects.

[0003] At present, the manufacturing methods of hand braces mainly include 3D printing, low-temperature thermoplastic materials and mechanical exoskeletons. Among them, although low-temperature thermoplastic materials have certain plasticity, they are difficult to adjust and maintain their shape. Mechanical exoskeletons have complex structures, high production costs, and are inconvenient to wear. 4D printing technology, as an emerging additive manufacturing technology, has gradually attracted attention. Based on 3D printing, 4D printing can not only build objects in three-dimensional space, but also make them deform in the time dimension according to external stimuli (such as temperature changes). This feature makes 4D printing show great potential in the medical field, especially in the manufacture of wearable devices and rehabilitation equipment. Regarding the manufacturing problems of existing orthotics for joints such as hands, there are problems such as high cost, limited material selection, and inability to monitor and adjust force feedback in real time.

[0004] Based on this, the present invention proposes a new type of joint brace with low cost, personalization and adjustable force feedback. The present invention aims to provide a more effective and personalization solution for the rehabilitation of joints such as hands through 4D printing technology combined with sensor technology. Summary of the invention

[0005] The purpose of the present invention is to use 4D printing technology to manufacture a low-cost, customizable, and adjustable force feedback smart hand brace. Compared with traditional brace manufacturing technology, the smart hand brace manufactured by this invention has lower cost, faster manufacturing speed, and can sense the patient's force feedback in real time.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for preparing an intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback comprises the following steps:

[0008] According to the structure of the joint, the basic structure of the brace is explored, and the structural form suitable for 4D printing is determined in the elastic and stretchable structure. The structural form should be able to initially meet the adaptability and comfort of the brace and joint movement after heat treatment deformation;

[0009] Predetermine the structural parameters in the structural form, and the mapping relationship between the key structural parameters and the force feedback, embed the mapping relationship in the model design software, and form a preliminary model according to the determined structural form, wherein the preliminary model is a sheet model with a certain thickness, and adjust the key structural parameters of the model according to the mapping relationship and the force feedback required for rehabilitation; and obtain a brace sheet model;

[0010] According to the brace sheet model, 3D printing is performed to obtain a sheet structure of the brace, which is heat treated to control deformation, and 4D printing is completed to transform the sheet structure into a three-dimensional structure, and after adjustment, an intelligent joint rehabilitation brace is obtained.

[0011] In the above technical solution, further, the elastic stretchable structure includes a structural part that adopts a curve design or a hollow design to make the material stretchable, or also includes a structural part for wearing and fixing.

[0012] Furthermore, for the finger rehabilitation brace, the structural form adapted for 4D printing adopts a diamond-shaped structure, and the diamond-shaped structure is a continuous diamond frame structure composed of two groups of support rod assemblies staggered to form a continuous diamond frame structure, and each group of support rod assemblies is a plurality of parallel support rods.

[0013] Furthermore, the continuous diamond frame structure includes four diamond units A, B, C, and D connected in sequence in the same direction. In this direction, the distance from the end of the diamond unit A to the center point of the diamond unit B is L1, the distance from the center point of the diamond unit B to the center point of the diamond unit C is L2, and the distance from the center point of the diamond unit C to the center point of the diamond unit D is L2; ​​in a direction perpendicular to this direction, the length of the two diagonals of the diamond unit A is πD1, the length of the two diagonals of the diamond unit B is πD2, the distance between the two ends of the diamond frame of the section C is πD3, and the distance between the two ends of the diamond frame of the section D is πD4; In the figure, L1 and L2 correspond to the distance from the metacarpophalangeal joint (MP) to the proximal interphalangeal joint (PIP) and the distance between the proximal interphalangeal joint (PIP) and the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP), respectively. D1, D2, D3, and D4 correspond to the diameter at the midpoint from the metacarpophalangeal joint (MP) to the proximal interphalangeal joint (PIP), the diameter at the proximal interphalangeal joint (PIP), the diameter at the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP), and the diameter at the distal interphalangeal joint (DIP), respectively.

[0014] Furthermore, the mapping relationship between key structural parameters and force feedback is determined, including:

[0015] A special structure test device is used to conduct experiments on a three-dimensional structure, i.e., a test brace, obtained by 4D printing based on the structure form, to accurately control and test the influence of different structural parameters on elastic force feedback, determine the key structural parameters, and further obtain the mapping relationship between the key structural parameters and force feedback; the structure test device includes:

[0016] A fixed platform, a force sensor and a protractor, wherein the test brace is assembled on the fixed platform to ensure that it is stably fixed on the fixed platform, one end of the force sensor is connected to the force-applying end of the test brace through a rigid connector, and while the force-applying end of the test brace is pulled down by the force sensor, the protractor measures the angle between the force-applying end of the test brace and its fixed end in real time to obtain force feedback of the test brace at different angles;

[0017] For the same key structural parameter, the force feedback data corresponding to different structural parameter values ​​at the same angle are obtained through experiments, and the data are fitted to obtain the mapping relationship between the key structural parameter and the force feedback at the angle, which is then embedded in the model design software.

[0018] Furthermore, for the diamond-shaped structure, the key structural parameters are beam width and thickness, and the beam width is the width of the support rod.

[0019] Furthermore, the intelligent joint rehabilitation brace is also provided with an additional structure, and the model of the additional structure is a sheet model, including a main structure and a connecting structure, the main structure has a structural unit with the same structural form, and the connecting structure is arranged on the main structure for connecting and fixing with the preliminary model to change the force feedback of the corresponding structure of the preliminary model.

[0020] Furthermore, in the 4D printing, PLA material is first used, and 3D printing is performed at a speed of 30-150 mm / s, a layer thickness of 0.1 mm, and a temperature of 230°C. After printing is completed, the printed part is placed at 60°C~70°C to deform it to form a three-dimensional structure.

[0021] Furthermore, before heat treatment and deformation in 4D printing, the printed part is arranged with a conductive tape for the sensor circuit line. After heat treatment and deformation, a sensor module is installed on the three-dimensional structure to form a sensor circuit together with the sensor circuit line to monitor the force feedback of the brace. In this stage, conductive tape and pressure sensors are used to monitor the force feedback provided by the brace in real time.

[0022] A 4D printing-based and customizable force feedback intelligent joint rehabilitation brace design system is used to implement the method described in any one of the above items, the system comprising: a force feedback adjustment module and a model display module, the force feedback adjustment module is used to adjust the key structural parameters of the preliminary model and the setting of the additional structure according to the mapping relationship between the key structural parameters and the force feedback, and the force feedback required for rehabilitation; the model display module is used to display the brace sheet model obtained after adjustment by the force feedback adjustment module, as well as the effect after 4D printing.

[0023] The beneficial effects of the present invention are:

[0024] The solution of the present invention provides a method for making an intelligent hand brace based on 4D printing. Compared with traditional methods such as thermoplasticity and plaster, this method can be designed and manufactured according to the size of the patient's hand, and shortens the brace production time and reduces the brace production cost. At the same time, the present invention integrates sensors to monitor the patient's hand rehabilitation force feedback data, providing the patient's quantitative rehabilitation data to the rehabilitation physician. Specifically, the present invention has the following advantages over the prior art:

[0025] - Cost-effectiveness: Using 4D printing technology and modular design, the production cost is lower than traditional smart orthotics.

[0026] - Adjustable force feedback: Traditional braces do not have the function of adjustable force feedback. The present invention provides a parametric design tool to customize the size of the force feedback, and also designs an additional structure to quickly adjust the force feedback of the brace.

[0027] - Easy customization: Parametric design tools allow users to quickly design and manufacture personalized hand braces to meet the diverse rehabilitation needs of patients.

[0028] - Real-time monitoring: The integrated thin-film pressure sensor monitors the force feedback data of the patient's rehabilitation cycle, and can use a visual interface to display the force feedback data of the patient using the hand brace. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The following is a flow chart of an operation method of an example of the present invention. A is a hand parameter measurement step; B is a parametric design tool; C is a 3D printing step; D is a polishing and manual cutting step; E is a circuit and sensor embedding step; F is a water bath heating step; G is a brace wearing and debugging step; H is a real-time monitoring and adjustment step.

[0030] Figure 2 An exploration process was developed for the structural design of the present invention.

[0031] Figure 3 The physiological dimension mapping principle of the diamond-shaped structure in the present invention is shown in FIG. a is the physiological parameter mark of the hand; b is the dimension parameter of the structure; c is the parameter of the thickness of the support rod in the structure; and d is the parameter of the thickness of the structure.

[0032] Figure 4 This is an experimental link of an embodiment of the present invention; a is a device for structural testing; b is a correlation data diagram between thickness and elastic force feedback; c is a correlation data diagram between support rod thickness and elastic force feedback.

[0033] Figure 5 This is an additional structure design of an embodiment of the present invention. a is the basic structure and the additional structure; b is the matching of the additional structure and the basic structure through buckles; c is the wearing effect without the additional structure; d is the wearing effect with the additional structure.

[0034] Figure 6 The structural test data of the additional structure in one embodiment of the present invention are shown in Figure 1. a is the additional structure test data of the basic structure with a thickness of 0.6 mm; b is the additional structure test data of the basic structure with a thickness of 0.8 mm.

[0035] Figure 7 It is a parametric design tool of an embodiment of the present invention. a is a data input interface; b is a parameter adjustment interface; c is a simulation interface after parameter adjustment; d is an additional structural parameter setting interface; and e is a deformation simulation interface.

[0036] Figure 8 A sensor module in an embodiment of the present invention.

[0037] Fig. 9This is the implementation step 1: measurement and modeling in an embodiment of the present invention. a is the patient diagnosis step; b is the joint parameter measurement step; c is the parameterized design step; d is the backend interface of the parameterized design tool.

[0038] Fig.10 This is the implementation step 2 of the present invention: 3D printing, adding circuits and water bath deformation. a shows the 3D printing step; b shows the circuit and sensor embedding step; c shows the water bath heating step; d shows the brace after the water bath is completed; d shows the brace polishing step.

[0039] Fig.11 This is the implementation step three of the present invention: wearing and monitoring. a shows the step of real-time monitoring by the sensor; b shows the step of water bath adjustment; c shows the overall effect of wearing on the hand. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0041] The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback of the present invention aims to provide personalized and adjustable force feedback for joint rehabilitation. Taking the finger joints of the hand as an example, the design and manufacturing process of the present invention is as follows: Figure 1 As shown, the following steps are included:

[0042] 1. According to the structure of the joint, explore the basic structure of the brace and determine the structural form suitable for 4D printing in the elastic stretchable structure. By collecting the key parameters of the joint, ensure that the structure can be deformed during the heat treatment process, and ensure the adaptability and comfort of the brace to the joint movement.

[0043] In the examples described in the present invention, a total of 4 structural forms of elastic stretchable structures were explored, such as Figure 2 As shown, they are: 1) Zipper type: a structure supported by a Z-shaped zipper with fixed parts at both ends; 2) Spring type: a structure supported by a surrounding spring with fixed parts at both ends; 3) Interlaced type: a staggered diamond structure designed based on the physiological structure characteristics of the joint; 5) Diamond type: a structure supported by a diamond stabilizing unit. After obtaining the preliminary structure through 4D printing and comparing and analyzing the actual wearing, the diamond type structure was finally selected as the basic structural form of the hand joint brace in this example. Specifically, it is a continuous diamond frame structure composed of two groups of support rod assemblies interlaced, and each group of support rod assemblies is a number of parallel support rods. Compared with other structural forms, it has the following advantages: 1) It has good deformation ability and elasticity, and can produce appropriate deformation under the action of external force; 2) The spatial configuration of the brace is adjustable, which can balance the requirements of joint mobility and elastic force feedback according to the patient's hand joint movement needs.

[0044] 2. Predetermine the structural parameters in the structural form, and the mapping relationship between the key structural parameters and the force feedback, embed the mapping relationship in the model design software, and form a preliminary model according to the determined structural form, wherein the preliminary model is a sheet model with a certain thickness, and adjust the key structural parameters of the model according to the mapping relationship and the force feedback required for rehabilitation to obtain a brace sheet model;

[0045] In this embodiment, by analyzing the relationship between the diamond-shaped structure and the physiological characteristics of the hand joints, some structural parameters of the diamond-shaped structure are determined; since there are multiple different joint structures in the fingers and there are physiological characteristics from thick to thin from the base to the fingertip, the key physiological parameters are selected: D1-D4, such as Figure 3 As shown in a, they correspond to the diameter at the midpoint from the metacarpophalangeal joint (MP) to the proximal interphalangeal joint (PIP), the diameter at the proximal interphalangeal joint (PIP), the diameter at the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP), and the diameter at the distal interphalangeal joint (DIP), as well as the distance between MP and PIP L1, and half of the distance between PIP and DIP L2, as the key shape parameters of the hand rhombus structure. According to the structure of the finger, a corresponding relationship is established between the rhombus structure and the key parts of the finger (such as the proximal phalanx and the middle phalanx). That is, the diamond sheet structure is designed to be a continuous diamond frame structure, which includes four diamond units A, B, C, and D connected in sequence in the same direction. In this direction, the distance from the end of the diamond unit A to the center point of the diamond unit B is L1, the distance from the center point of the diamond unit B to the center point of the diamond unit C is L2, and the distance from the center point of the diamond unit C to the center point of the diamond unit D is L2, wherein L1 and L2 correspond to the distance from the metacarpophalangeal joint (MP) to the proximal interphalangeal joint (PIP) and the distance from the proximal interphalangeal joint (PIP) to the proximal interphalangeal joint (PIP), respectively. IP) and the midpoint of the distal joint (DIP); perpendicular to this direction, the length of the two diagonals of the A rhombus unit is πD1, the length of the two diagonals of the B rhombus unit is πD2, the spacing between the two ends of the C rhombus frame is πD3, and the spacing between the two ends of the D rhombus frame is πD4; after the preliminary structural parameters of the structural form are determined, the key structural parameters affecting its force feedback should be further determined. In this embodiment, the diagonal length, beam width (strut width) and thickness of the rhombus unit in the rhombus structure are often the key parameters affecting its elastic force feedback. By conducting mechanical experiments on the braces obtained from the rhombus unit rhombus structure of different sizes and thicknesses, and combining fitting, the mapping relationship between each key parameter and the elastic force feedback can be obtained.

[0046] Furthermore, in this example, in order to accurately control and test the effects of different structural parameters on elastic force feedback, a special structural testing device was designed. The device is intended to test the mechanical properties of the brace under different structural designs, including the effects of parameters such as brace thickness and beam width on elastic force feedback, as well as the performance of the brace at different joint angles. By experimentally testing the effects of different beam widths and thicknesses on elastic force feedback, it was found that an increase in beam width and thickness will directly increase the strength of the elastic force, and they are determined to be key structural parameters. Therefore, in order to provide appropriate rehabilitation training intensity while ensuring comfort, the present invention embeds adjustable beam width and thickness parameter functions in the model design to allow fine-tuning according to the patient's rehabilitation stage and individual differences.

[0047] The structural test device described is mainly composed of the following three parts: 1) Fixed platform: used to support and fix the test brace to ensure the stability of the brace during the experiment. The design of the platform ensures that the brace can be firmly fixed in the specified position when external force is applied to avoid affecting the test results due to movement. 2) Dynamometer: a force sensor used to measure in real time the force applied by the brace at different angles. The dynamometer can accurately record the force feedback of the brace at various angles to ensure that the change in force is closely related to the structural parameters of the brace. 3) Electronic protractor: used to accurately measure the bending angle of the brace to ensure that the change in angle is recorded at different stages of the experiment. The protractor can work in conjunction with the force sensor and other components to accurately control the angle of force application. Figure 4 As shown in a, the specific operation steps of the structure experiment are as follows:

[0048] Step 1: Preparation

[0049] Before the experiment begins, first 4D print the three-dimensional structure of the structure under the required research parameters, that is, the test brace, and assemble the test brace on the fixed platform to ensure that the test brace is stably fixed on the platform. The brace is installed in a way that ensures that it can remain unchanged throughout the experiment to avoid affecting the test results due to movement or instability. Connect the force sensor and electronic protractor to the external electronic recording device to ensure that these instruments can accurately record the applied force and bending angle. At this point, the electronic recording device is ready to receive signals from the force sensor and protractor.

[0050] Step 2: Apply force and record data

[0051] In the test, the force sensor is connected to the force-applying end of the brace to be tested through a thin wire, and the protractor is adjusted to a specified angle (such as 15°, 30°, etc.). Then, the force sensor is gradually pulled by slowly and steadily applying force until the brace reaches the set bending angle. During the force application process, the force sensor will record the applied force in real time and record it through an electronic recording device. At the same time, the electronic protractor will accurately measure and record the bending angle of the brace.

[0052] Step 3: Repeat the experiment and analyze the data

[0053] In order to ensure the reliability of the test results, each set of experiments will be repeated three times to ensure the stability and repeatability of the data. After each experiment is completed, the recording instrument will save the data and display the relationship between the elastic force and the joint angle in a graphical manner. During the experiment, the parameters of the brace (such as beam width, thickness, etc.) will be adjusted for multiple tests to compare the differences in the mechanical properties of the brace under different parameters. For the same key structural parameter, the force feedback data corresponding to the values ​​of different structural parameters at the same angle are obtained through experiments, and they are fitted to obtain the mapping relationship between the key structural parameter and the force feedback at the angle, which is embedded in the model design software.

[0054] Through the above test device and process, the influence of different structural units on elastic force feedback can be accurately tested. The experimental results in this embodiment show that the thickness and beam width of the brace have an important influence on the elastic force feedback. Increasing the thickness and beam width will increase the elastic force of the brace (for example, Figure 4 The experimental data can reveal the mapping relationship between structure and force feedback, and after fitting, it can support the development of parametric design tools, thereby providing stronger rehabilitation support for patients.

[0055] In addition, an additional structure is also designed in the present invention. The additional structure is a modular design, which can be combined with the basic structure of the brace, and assembled and adjusted by plug-in, heat treatment and the like. The design idea of ​​the additional structure is to make the brace more flexible in elastic force feedback by adding an adjustable level to adapt to changes in force requirements during the patient's rehabilitation process. Specifically, the model of the additional structure is a sheet model, which is mainly divided into two parts: 1) the main structure: a structural unit with the same structural form as the basic structure; 2) a connecting structure: provided on the main structure for connecting and fixing with the preliminary model to change the force feedback of the corresponding structure of the preliminary model. For example, the additional structure is fixed to the basic brace through a designed plug-in joint. The plug-in structure ensures the stability of the additional part, and the user can easily replace or adjust the additional part according to actual conditions.

[0056] Furthermore, the additional structure and the basic structure can also be adapted through heat treatment. After the additional structure is combined with the basic brace, the two parts can be deformed together through heat treatment such as water bath heating to ensure that the additional structure and the basic brace are perfectly matched. This heat treatment method can not only adjust the overall shape of the brace, but also ensure that the force feedback characteristics of the additional part match the basic part. The additional structure is fixed to the basic brace through the designed plug-in connector. The plug-in structure ensures the stability of the additional part, and the user can easily replace or adjust the additional part according to actual conditions.

[0057] In addition, the same experimental method as above can also be used to study the changes between the additional structure and the force feedback. In this embodiment, the thickness of the additional structure is adjusted to test the elastic force feedback provided by the brace under different configurations, and the force change curve is recorded. The experimental results show that the additional structure can effectively change the force feedback strength of the brace to meet the needs of different rehabilitation stages. Figure 6 shown.

[0058] In this embodiment, a parametric design tool is also provided by the above method. The tool is mainly implemented by model design software such as Rhino Grasshopper software. Figure 7 As shown, a force feedback adjustment module and a model display module are set in the tool. The force feedback adjustment module is used to adjust the key structural parameters of the preliminary model and the setting of the additional structure according to the mapping relationship between the key structural parameters and the force feedback, and the force feedback required for rehabilitation; the model display module is used to display the brace sheet model obtained after adjustment by the force feedback adjustment module, and the effect after 4D printing. The tool designs the shape of the hand brace according to the patient's specific parameters (finger joint size). The tool customizes force feedback according to the patient's rehabilitation needs by adjusting parameters such as thickness, beam width and overall shape.

[0059] 3. Perform 3D printing according to the brace sheet model to obtain a sheet structure of the brace, perform heat treatment on it to control deformation, complete 4D printing to transform the sheet structure into a three-dimensional structure, and obtain an intelligent joint rehabilitation brace after adjustment.

[0060] Specifically, in this embodiment, the brace is manufactured using 4D printing technology and printed using PLA (polylactic acid) material. PLA material has good thermal deformation properties and can deform in response to external heat, meeting the requirements for brace production. During the printing process, the 3D printer used was Raise3D E2, and the following main parameters were set during printing: Printing speed: 30-150mm / s, adjusted according to the complexity and precision requirements of the brace; Printing layer thickness: 0.1mm, to ensure that the printed brace has a smooth surface and stable mechanical properties; Printing temperature: 230°C, to ensure that the material can be melted evenly and avoid printing defects due to unstable temperature.

[0061] Furthermore, after 3D printing is completed, the core process of the brace is heating deformation treatment. The purpose of the heating process is to transform the brace from a two-dimensional plane state to a three-dimensional structure that conforms to the patient's hand shape. The specific steps are as follows:

[0062] 1) Heating equipment preparation: Use a temperature-controlled water bath to heat the brace. The temperature range of the water bath is set between 60°C and 70°C;

[0063] 2) Heating process: Immerse the printed and post-processed brace in a water bath preheated to 60°C to 70°C to ensure that the PLA material can soften and deform, but not overheat and cause the material to melt or deform excessively. The heating time is 2 to 3 minutes, which should be adjusted appropriately according to the thickness of the brace and the printing density. Under the action of the hot water in the water bath, the PLA material begins to soften and gradually deform. During the heating process, the brace will deform in the preset direction to form a three-dimensional shape that conforms to the anatomical structure of the hand;

[0064] 3) Deformation control: During the heating process, the deformation of the brace is guided by the structural units (such as diamond units, beam width and thickness) pre-set in the design. After being heated, each structural unit of the brace is appropriately bent according to the thermal deformation characteristics of the material, so that the contact surface between the brace and the hand fits better. After heating, the shape of the brace will fit the patient's fingers, joints and other parts as much as possible to ensure comfort and functionality when worn;

[0065] In addition, conductive tape can be used to arrange the sensor circuit before heating and deformation. After heating, deformation and shape adjustment are completed, the brace will enter the installation stage of the sensor module, such as installing a pressure sensor, so as to monitor the force feedback provided by the brace in real time. The specific steps are: 1) Sensor installation: The magnetic installation method can be used to install the conductive tape on the surface of the brace according to the preset circuit diagram. After that, the tape and components such as the sensor are fixed by magnetic connectors; 2) Debugging and testing: After the installation is completed, connect the sensor to the external monitoring equipment, debug and test the sensor to ensure that the sensor can accurately sense the force changes of the brace during use and transmit data to the monitoring equipment. Embedded pressure sensors are integrated into the orthosis and placed at the key stress points of the orthosis to monitor the force applied by the patient during rehabilitation. These sensors can provide real-time data to rehabilitation therapists or medical staff to monitor and adjust the hand brace. The embedded pressure sensor transmits the pressure sensor signal to a computer or smart phone via Bluetooth to achieve remote monitoring function. Such as Figure 8 , two Φ5 × 1 mm N52 neodymium magnets need to be embedded at the bottom of the pressure sensor with the help of conductive adhesive to connect to the GND and analog input ports of the controller. The embedded pressure sensor and the brace are connected by conductive tape, and the signal controller and lithium battery are placed in the hardware housing with a magnet, and are adsorbed on the magnet of the brace circuit by the suction of the magnet. After the brace is heated and deformed and the sensor is installed, the final wearing test will be carried out. The rehabilitation physician or brace making expert will make adaptation adjustments according to the actual situation of the patient's hand to ensure that the brace can provide the required force feedback and achieve the rehabilitation effect in actual use. The final form of the brace can be fine-tuned according to the patient's hand size and rehabilitation needs to ensure that it has good comfort and functionality, and can help patients to smoothly carry out rehabilitation training.

[0066] It can be seen that the design of the present invention can provide a comprehensive solution for the personalized rehabilitation of patients. And it can greatly simplify the customized preparation process of joint rehabilitation braces, such as Fig. 9 , 10 As shown in , 11, by using the system and method developed by the present invention, the design and preparation of joint rehabilitation braces can be completed conveniently and efficiently. First, the patient's hands and other joints are evaluated and measured. Taking the hand as an example, the circumference of the fingers and the length between the joints are measured. These data are input into the parametric design tool we developed, and the design tool will automatically generate the preliminary structure of the hand orthosis, including four diamond units. According to the patient's rehabilitation needs, the force feedback parameters such as beam width and thickness are adjusted, or in the rehabilitation process, the force feedback of the orthosis is changed by adding additional structures to ensure that the orthosis provides appropriate force feedback at different bending angles.

[0067] The patient monitors the force feedback during the rehabilitation training process through the controller and pressure sensor magnetically attached to the brace during the continuous rehabilitation movement of the finger. The sensor data is transmitted to a computer or smartphone via Bluetooth for real-time monitoring by doctors and patients. During long-term use, the orthosis may be deformed due to frequent bending. In this case, the orthosis can be reshaped by a secondary heating treatment. The orthosis is placed in a water bath again to heat it and then manually adjusted to restore its original shape or adjust it according to the patient's rehabilitation progress.

[0068] The present invention has carried out a large number of experimental verifications, which proves the feasibility and effectiveness of the method. In the future, the technology can be further extended to the rehabilitation application of other joints.

[0069] The above-described embodiments are only some of the preferred solutions of the present invention, but they are not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A method for preparing an intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback, characterized in that: The steps include: According to the structure of the joint, the basic structure of the brace is explored, and the structural form suitable for 4D printing is determined in the elastic and stretchable structure. The structural form should be able to initially meet the adaptability and comfort of the brace and joint movement after heat treatment deformation; Predetermine the structural parameters in the structural form, and the mapping relationship between the key structural parameters and the force feedback, embed the mapping relationship in the model design software, and form a preliminary model according to the determined structural form, wherein the preliminary model is a sheet model with a certain thickness, and adjust the key structural parameters of the model according to the mapping relationship and the force feedback required for rehabilitation; and obtain a brace sheet model; According to the brace sheet model, 3D printing is performed to obtain a sheet structure of the brace, which is heat treated to control deformation, and 4D printing is completed to transform the sheet structure into a three-dimensional structure, and after adjustment, an intelligent joint rehabilitation brace is obtained.

2. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 1, characterized in that: The elastic stretchable structure includes a structural part that adopts a curve design or a hollow design to make the material stretchable, or also includes a structural part for wearing and fixing.

3. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 1, characterized in that: For the finger rehabilitation brace, the structural form adapted for 4D printing is a diamond-shaped structure, which is a continuous diamond-shaped frame structure composed of two groups of support rod assemblies staggered to form a plurality of parallel support rods.

4. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 3, characterized in that: The continuous diamond frame structure comprises four diamond units A, B, C, and D connected in sequence in the same direction. In this direction, the distance between the end of diamond unit A and the center point of diamond unit B is L1, the distance between the center point of diamond unit B and the center point of diamond unit C is L2, and the distance between the center point of diamond unit C and the center point of diamond unit D is L2; ​​in a direction perpendicular to this direction, the length of the two diagonals of diamond unit A is πD1, the length of the two diagonals of diamond unit B is πD2, the distance between the two ends of diamond frame section C is πD3, and the distance between the two ends of diamond frame section D is πD4; wherein, L 1. L2 corresponds to the distance from the metacarpophalangeal joint (MP) to the proximal interphalangeal joint (PIP) and the distance between the proximal interphalangeal joint (PIP) and the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP), respectively. D1, D2, D3, and D4 correspond to the diameter at the midpoint from the metacarpophalangeal joint (MP) to the proximal interphalangeal joint (PIP), the diameter at the proximal interphalangeal joint (PIP), the diameter at the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP), and the diameter at the distal interphalangeal joint (DIP), respectively.

5. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to any one of claims 1 to 4, characterized in that: Determine the mapping relationship between key structural parameters and force feedback, including: A special structure test device is used to conduct experiments on a three-dimensional structure, i.e., a test brace, obtained by 4D printing based on the structure form, to accurately control and test the influence of different structural parameters on elastic force feedback, determine the key structural parameters, and further obtain the mapping relationship between the key structural parameters and force feedback; the structure test device includes: A fixed platform, a force sensor and a protractor, wherein the test brace is assembled on the fixed platform to ensure that it is stably fixed on the fixed platform, one end of the force sensor is connected to the force-applying end of the test brace through a rigid connector, and while the force-applying end of the test brace is pulled down by the force sensor, the protractor measures the angle between the force-applying end of the test brace and its fixed end in real time to obtain force feedback of the test brace at different angles; For the same key structural parameter, the force feedback data corresponding to different structural parameter values ​​at the same angle are obtained through experiments, and the data are fitted to obtain the mapping relationship between the key structural parameter and the force feedback at the angle, which is then embedded in the model design software.

6. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 5, characterized in that: For the diamond-shaped structure, the key structural parameters are beam width and thickness, and the beam width is the width of the support rod.

7. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 6, characterized in that: The intelligent joint rehabilitation brace is also provided with an additional structure, and the model of the additional structure is a sheet model, including a main structure and a connecting structure. The main structure has a structural unit with the same structural form, and the connecting structure is arranged on the main structure for connecting and fixing with the preliminary model to change the force feedback of the corresponding structure of the preliminary model.

8. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 1, characterized in that: In the 4D printing, PLA material is first used to perform 3D printing at a speed of 30-150 mm / s, a layer thickness of 0.1 mm, and a temperature of 230° C. After printing is completed, the printed part is placed at 60° C. to 70° C. to deform it to form a three-dimensional structure.

9. The method for preparing the intelligent joint rehabilitation brace based on 4D printing and with customizable force feedback according to claim 1, characterized in that: Before heat treatment and deformation in 4D printing, the printed part is arranged with conductive tape for sensor circuit lines. After heat treatment and deformation, the sensor module is installed on the three-dimensional structure to form a sensor circuit together with the sensor circuit line to monitor the force feedback of the brace. Conductive tape and pressure sensor are used in this stage to monitor the force feedback provided by the brace in real time.

10. An intelligent joint rehabilitation brace design system based on 4D printing and customizable force feedback, characterized in that: Used to implement the method described in any one of claims 1 to 9, the system includes: a force feedback adjustment module and a model display module, the force feedback adjustment module is used to adjust the key structural parameters of the preliminary model and the setting of the additional structure according to the mapping relationship between the key structural parameters and the force feedback, and the force feedback required for rehabilitation; the model display module is used to display the brace sheet model obtained after adjustment by the force feedback adjustment module, as well as the effect after 4D printing.

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