Intelligent Joint Rehabilitation Brace Based on 4D Printing and Customizable Force Feedback, Preparation Method and System Thereof

Abstract

The present invention discloses a preparation method and system for an intelligent joint rehabilitation brace based on 4D printing and customizable force feedback. According to the structure of the joint part, the structural form adapted to 4D printing is determined, and the structural parameters in the structural form and the mapping relationship between the key structural parameters and the force feedback are determined in advance and embedded in the model design software. The key structural parameters of the model can be adjusted accordingly according to the mapping relationship and the force feedback required for rehabilitation to obtain a brace sheet model. Through 4D printing, a three-dimensional structure is formed, and after adjustment, an intelligent joint rehabilitation brace is obtained. Compared with the traditional brace manufacturing technology, the intelligent hand brace manufactured by the present invention has a lower cost, a faster production speed, and can have the function of real-time sensing of the magnitude of the patient's force feedback.

Description

Technical Field

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

[0002] All kinds of joint parts play a crucial role in daily life. Taking the hand as an example, due to the complexity and fragility of its structure, hand joints are extremely vulnerable to injuries such as fractures, soft tissue contusions, and muscle strains. These injuries will seriously affect the patient's daily life and working ability. Therefore, the rehabilitation of hand injuries is particularly important. Traditional hand rehabilitation usually relies on hand orthoses to provide support and rehabilitation. However, existing hand orthoses have many limitations. First of all, most orthoses lack the ability to adjust dynamically with force feedback 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 do not fully consider the differences in individual hand sizes, resulting in low patient wearing compliance and affecting the rehabilitation effect.

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

[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 personalized solution for joint rehabilitation such as the hand 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 an intelligent hand brace with low cost, customizable personalization, and adjustable force feedback function. Compared with traditional brace manufacturing technologies, the intelligent hand brace manufactured by this invention has lower costs, faster production speed, and can have the function of real-time sensing of the magnitude of the patient's force feedback.

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

[0007] Preparation method of intelligent joint rehabilitation brace based on 4D printing and customizable force feedback, comprising the following steps:

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

[0009] Pre-determine the structural parameters in the structural form, as well as 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. The preliminary model is a sheet model with a certain thickness. Adjust the key structural parameters of the model according to the mapping relationship and the force feedback required for rehabilitation to obtain the brace sheet model.

[0010] Perform 3D printing according to the brace sheet model to obtain the 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 adjust to obtain the intelligent joint rehabilitation brace.

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

[0012] Further, for finger rehabilitation braces, the structural form suitable for 4D printing is selected as a rhombus plate structure. The rhombus plate structure is a continuous rhombus frame structure formed by the staggered arrangement of two groups of strut assemblies, and each group of strut assemblies is composed of several parallel struts.

[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 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; 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; 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), respectively.

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

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

[0016] A fixed platform, a force sensor, and a protractor. 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 via a rigid connector. 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, 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 force feedback at the angle, which is then embedded in the model design software.

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

[0019] Furthermore, an additional structure is provided in the intelligent joint rehabilitation brace. The model of the additional structure is a sheet model, including a main structure and a connection structure. The main structure has structural units with the same structural form as the above-mentioned structure, and the connection 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 carried out 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 cause deformation and form a three-dimensional structure.

[0021] Furthermore, before heat treatment deformation in 4D printing, conductive tapes are used to arrange the sensing circuit lines on the printed part. After heat treatment deformation, a sensor module is installed on the three-dimensional structure to jointly form a sensing circuit with the sensing circuit lines to monitor the force feedback of the brace. Conductive cloth tapes and pressure sensors are used at this stage to monitor the force feedback provided by the brace in real time.

[0022] An intelligent joint rehabilitation brace design system based on 4D printing and customizable force feedback, used to implement the method described in any one of the above, the system includes: a force feedback adjustment module and a model display module. The force feedback adjustment module is used to adjust the key structure parameters of the preliminary model and the setting of the additional structure according to the mapping relationship between the key structure parameters and the force feedback, and the force feedback required for rehabilitation; the model display module is used to display the sheet model of the brace obtained after being adjusted by the force feedback adjustment module, and 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 manufacturing an intelligent hand brace based on 4D printing. Compared with traditional methods such as thermoplastics and plaster, this method can perform personalized design and manufacturing according to the hand size of the patient, shorten the production time of the brace, and reduce the production cost of the brace. At the same time, the present invention integrates sensors to monitor the hand rehabilitation force feedback data of the patient, providing quantitative rehabilitation data of the patient for rehabilitation physicians. Specifically, the present invention has the following advantages compared with the prior art:

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

[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 magnitude of the force feedback, and also designs an additional structure to quickly adjust the force feedback of the brace.

[0027] - Easy customization: The parametric design tool allows users to quickly design and manufacture personalized hand braces to meet the diverse rehabilitation needs of patients.

[0028] - Real-time monitoring: Integrated thin-film pressure sensors monitor the force feedback data during the patient's rehabilitation cycle and can display the force feedback data of the patient using the hand brace through a visual interface. Description of the Drawings

[0029] Figure 1 Schematic diagram of the operation method process for an example of the present invention. Where a is the hand parameter measurement step; b is the parametric design tool; c is the 3D printing step; d is the grinding and manual cutting step; e is the embedding step of the circuit and sensor; f is the water bath heating step; g is the brace wearing and debugging step; h is the real-time monitoring and adjustment step.

[0030] Figure 2 Structural design exploration process of the present invention.

[0031] Figure 3 Physiological size mapping principle of the diamond-shaped structure in the present invention. a is the physiological parameter annotation of the hand; b is the size parameter of the structure; c is the parameter of the thickness of the struts in the structure; d is the parameter of the thickness of the structure.

[0032] Figure 4 Experimental session of an embodiment of the present invention; a is the device for the structure test; b is the correlation data graph between the thickness and the elastic force feedback; c is the correlation data graph between the thickness of the struts and the elastic force feedback.

[0033] Figure 5 Additional structural design of an embodiment of the present invention. a is the basic structure and the additional structure; b is the cooperation between the additional structure and the basic structure achieved through a buckle; c is the wearing effect without the additional structure; d is the wearing effect with the additional structure.

[0034] Figure 6 Structural experimental data of the additional structure in an embodiment of the present invention. a is the experimental data of the additional structure with a basic structure thickness of 0.6 mm; b is the experimental data of the additional structure with a basic structure thickness of 0.8 mm.

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

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

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

[0038] Figure 10 Step 2 of the implementation 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; d shows the brace polishing step.

[0039] Figure 11 Step 3 of the implementation of the present invention: Wearing and monitoring. a shows the real-time monitoring step of the sensor; b shows the water bath adjustment step; c shows the overall effect of wearing on the hand. Detailed implementation manner

[0040] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] The preparation method of the intelligent joint rehabilitation brace based on 4D printing and 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 Figure 1 shown and includes the following steps:

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

[0043] In the example of the present invention, a total of 4 structure forms of elastic stretchable structures are explored, as Figure 2 shown, which are respectively: 1) Zip type: a structure supported by a Z-shaped zip with fixed parts at both ends; 2) Spring type: a structure supported by a surrounding spring with fixed parts at both ends; 3) Interleaved type: an interleaved diamond structure designed based on the physiological structure characteristics of the joint; 5) Rhombus plate type: a structure supported by a rhombus stable unit. After obtaining the preliminary structure through 4D printing and comparing and analyzing through actual wearing, the rhombus plate type structure is finally selected as the basic structure form of the hand joint brace in this example, which is specifically a continuous diamond frame structure formed by the interleaving of two groups of rod assemblies, and each group of rod assemblies is composed of several parallel rods. Compared with other structure forms, it has the following advantages: 1) It has good deformation ability and elasticity and can generate appropriate deformation under external force; 2) The spatial configuration of the brace is adjustable, and it can balance the requirements of joint mobility and elastic force feedback according to the needs of the patient's hand joint movement.

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

[0045] In this embodiment, by analyzing the relationship between the rhombus-shaped structure and the physiological characteristics of the hand joints, some structural parameters of the rhombus-shaped structure are determined. Since there are multiple different joint structures in the finger part and the physiological characteristic of getting thinner from the finger root to the fingertip, the key physiological parameters: D1-D4 are selected. As shown in a of Figure 3 it, they respectively 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 L1 between MP and PIP, and half of the distance L2 between PIP and DIP, which are used as the key external shape parameters of the hand rhombus structure. According to the structure of the finger, a corresponding relationship is established between the rhombus-shaped structure and the key parts of the finger (such as the proximal phalanx and the middle phalanx). That is: design the said rhombus-shaped structure as a continuous rhombus frame structure, which includes four rhombus units A, B, C, and D connected in sequence in the same direction. In this direction, the distance from the end of the A rhombus unit to the center point of the B rhombus unit is L1, the distance from the center point of the B rhombus unit to the center point of the C rhombus unit is L2, and the distance from the center point of the C rhombus unit to the center point of the D rhombus unit is L2. Among them, L1 and L2 respectively correspond to the distance from the metacarpophalangeal joint (MP) of the finger to the proximal interphalangeal joint (PIP) and the distance from the proximal interphalangeal joint (PIP) to the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP); in the direction perpendicular to this direction, the lengths of the two diagonals of the A rhombus unit are πD1, the lengths of the two diagonals of the B rhombus unit are πD2, the distance between the two ends of the C-section rhombus frame is πD3, and the distance between the two ends of the D-section 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-shaped structure are often the key parameters affecting its elastic force feedback. By conducting mechanical experiments on the braces obtained from the rhombus-shaped structures of rhombus units with different sizes and different thicknesses and combining fitting, the mapping relationship between each key parameter and the elastic force feedback can be obtained.

[0046] Furthermore, in this example, to precisely control and test the influence of different structural parameters on elastic force feedback, a special structural test device was designed. This device aims to test the mechanical properties of the brace under different structural designs, including the influence 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 influence of different beam widths and thicknesses on elastic force feedback, it was found that increasing the beam width and thickness would directly enhance the strength of the elastic force, determining that they are both key structural parameters. Therefore, in order to provide an appropriate rehabilitation training intensity while ensuring comfort, the present invention incorporates adjustable beam width and thickness parameter functions in the model design to allow for fine-tuning according to the patient's rehabilitation stage and individual differences.

[0047] The described structural test device mainly consists 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 when an external force is applied, the brace can be firmly fixed in the specified position, avoiding affecting the test results due to movement. 2) Dynamometer: That is, a force sensor, used to measure the magnitude of the force exerted by the brace at different angles in real time. The dynamometer can accurately record the force feedback of the brace at each angular position, ensuring 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 the recording of angle changes at different experimental stages. The protractor can work in coordination with the force sensor and other components to precisely control the angle of the applied force. As Figure 4 shown in a of, the specific operation steps of the structural experiment are as follows:

[0048] Step 1: Preparation work

[0049] Before the experiment starts, first obtain the three-dimensional solid structure, that is, the test brace, obtained by 4D printing of the structural form under the required research parameters, and assemble the test brace onto the fixed platform to ensure that the test brace is stably fixed on the platform. The installation method of the brace ensures that it can remain unchanged throughout the experiment, avoiding affecting the test results due to movement or instability. Connect the force sensor and the electronic protractor to an external electronic recording device to ensure that these instruments can accurately record the applied force and bending angle. At this time, the electronic recording device is ready to receive signals from the force sensor and the protractor.

[0050] Step 2: Apply force and record data

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

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

[0053] To ensure the reliability of the test results, each group of experiments was repeated three times to ensure the stability and repeatability of the data. After each experiment was completed, the recording instrument would save the data and display the relationship between the elastic force and the joint angle in the form of a chart. During the experiment, the parameters of the brace (such as beam width, thickness, etc.) were also adjusted for multiple tests to compare the mechanical property differences of the brace under different parameters. For the same key structural parameter, the force - feedback data corresponding to different structural - parameter values at the same angle were obtained through experiments, and they were fitted to obtain the mapping relationship between this key structural parameter and the force feedback at this angle, and then embedded it into the model - design software.

[0054] Through the above test device and process, the influence of different structural units on the elastic - force feedback can be accurately tested. In this embodiment, the experimental results 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 (specifically as shown in b and c in Figure 4 )). The experimental data can reveal the mapping relationship between the structure and the force feedback. 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 designed in the present invention. The additional structure is a modular design that can be combined with the basic structure of the brace and assembled and adjusted through plug - in, heat treatment, etc. The design idea of the additional structure is to make the brace more flexible in terms of elastic - force feedback by adding an adjustable level to adapt to the change of force requirements during the patient's rehabilitation process. Specifically, the model of the additional structure is a sheet - like model, which is mainly divided into two parts: 1) The main structure: It has the same structural units as the structural form of the basic structure; 2) The connection structure: It is arranged on the main structure and used to connect and fix 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 users can easily replace or adjust the additional part according to the actual situation.

[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, heat treatment methods such as water bath heating can be used to deform the two parts together, ensuring a perfect fit between the additional structure and the basic brace. 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 those of the basic part. The additional structure is fixed to the basic brace through the designed plug-in joint, and the plug-in structure ensures the stability of the additional part, and the user can easily replace or adjust the additional part according to the actual situation.

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

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

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

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

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

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

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

[0064] 3) Deformation control: During the heating process, the deformation of the brace is guided by the pre-set structural units in the design (such as diamond units, beam width, and thickness). Each structural unit of the brace bends appropriately according to the thermal deformation characteristics of the material after being heated, so that the contact surface between the brace and the hand is more fitting. After heating, the shape of the brace will fit as closely as possible to the patient's fingers, joints, etc., ensuring comfort and functionality during wearing;

[0065] In addition, a conductive cloth tape can be used to arrange the sensing circuit lines before heat deformation. After the heat deformation and form adjustment are completed, the brace will enter the installation stage of the sensor module, such as installing a pressure sensor to monitor the force feedback provided by the brace in real time. The specific steps are as follows: 1) Sensor installation: The magnetic installation method can be adopted to install the conductive cloth tape on the surface of the brace according to the preset wiring diagram. After that, the cloth tape and other components such as the sensor are fixed through magnetic connectors; 2) Debugging and testing: After installation, connect the sensor to an external monitoring device and conduct debugging and testing of the sensor to ensure that the sensor can accurately sense the force changes during the use of the brace and transmit data to the monitoring device. The embedded pressure sensor is integrated into the orthosis and placed at the key stress points of the orthosis to monitor the force applied during the patient's rehabilitation. These sensors can provide real-time data for 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 smartphone via Bluetooth to achieve the remote monitoring function. For example 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 a conductive tape. The signal controller and the lithium battery are placed in a hardware shell with a magnet, and are adsorbed on the magnet of the brace circuit by the suction force of the magnet. After the brace undergoes heat deformation and sensor installation, a final wearing test will be carried out. The rehabilitation physician or brace manufacturing expert will make an adaptation adjustment 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 during actual use. The final form of the brace can be finely adjusted according to the patient's hand size and rehabilitation needs to ensure its good comfort and functionality, and can help the patient carry out rehabilitation training smoothly.

[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 Figure 9 , 10 , as shown in Fig. 11, 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 joints of the patient's hand, etc. are evaluated and measured. Taking the hand as an example, it includes measuring the circumference of the fingers and the length between the joints. 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, adjust the force feedback parameters, such as the beam width and thickness, or during the rehabilitation process, change the force feedback of the orthosis by adding additional structures to ensure that the orthosis provides appropriate force feedback at different bending angles.

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

[0068] A large number of experimental verifications have been carried out in this invention, proving the feasibility and effectiveness of this method. In the future, this technology can be further extended to the rehabilitation applications of other joints.

[0069] The above-described embodiments are only some of the better solutions of the present invention, but they are not intended to limit the present invention. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. Preparation method of an intelligent joint rehabilitation brace based on 4D printing and customizable force feedback, characterized in that, The steps include the following: According to the structure of the joint part, explore the basic structure of the brace, and determine the structural form suitable for 4D printing in the elastic stretchable structure. The structural form should be able to initially meet the adaptability and comfort of the brace to joint movement after heat treatment deformation; Pre-determine the structural parameters in the structural form, as well as 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. The preliminary model is a sheet model with a certain thickness. Adjust the key structural parameters of the model according to the mapping relationship and the force feedback required for rehabilitation; obtain the sheet model of the brace; Perform 3D printing according to the sheet model of the brace to obtain the sheet structure of the brace, perform heat treatment on it to control the deformation, complete 4D printing to transform the sheet structure into a three-dimensional structure, and adjust to obtain the intelligent joint rehabilitation brace.

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

3. The preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to claim 1, wherein, For the finger rehabilitation brace, the structural form suitable for 4D printing is selected as the rhombus plate type structure. The rhombus plate type structure is a continuous rhombus frame structure formed by the staggered arrangement of two groups of strut assemblies, and each group of strut assemblies is composed of several parallel struts.

4. The preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to claim 3, characterized in that, The continuous rhombus frame structure includes four rhombus units A, B, C, and D connected in sequence in the same direction. In this direction, the distance from the end of the A rhombus unit to the center point of the B rhombus unit is L1, the distance from the center point of the B rhombus unit to the center point of the C rhombus unit is L2, and the distance from the center point of the C rhombus unit to the center point of the D rhombus unit is L2; in the direction perpendicular to this direction, the lengths of the two diagonals of the A rhombus unit are πD1, the lengths of the two diagonals of the B rhombus unit are πD2, the distance between the two ends of the C-section rhombus frame is πD3, and the distance between the two ends of the D-section rhombus frame is πD4; where L1 and L2 respectively correspond to the distance from the metacarpophalangeal joint (MP) of the finger to the proximal interphalangeal joint (PIP) and the distance from the proximal interphalangeal joint (PIP) to the midpoint between the proximal interphalangeal joint (PIP) and the distal interphalangeal joint (DIP), and D1, D2, D3, and D4 respectively 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).

5. The preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to any one of claims 1 to 4, characterized in that, Determine the mapping relationship between the key structural parameters and the force feedback, specifically including: Use a special structural test device to conduct experiments on the three-dimensional structure (i.e., the test brace) obtained by 4D printing based on the structural form, accurately control and test the influence of different structural parameters on the elastic force feedback, determine the key structural parameters, and further obtain the mapping relationship between the key structural parameters and the force feedback; the structural test device includes: A fixed platform, a force sensor and a protractor. The test fixture is assembled on the fixed platform to ensure its stable fixation on the fixed platform. One end of the force sensor is connected to the force application end of the test fixture through a rigid connector. While pulling down the force application end of the test fixture through the force sensor, the protractor measures the angle between the force application end and the fixed end of the test fixture in real time to obtain the force feedback of the test fixture 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 they are fitted to obtain the mapping relationship between this key structural parameter and the force feedback at this angle, and it is embedded in the model design software.

6. The preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to claim 3, wherein, For the rhombus-shaped structure, its key structural parameters are the beam width and thickness, and the beam width is the width of the strut.

7. The preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to claim 6, characterized in that, An additional structure is also provided in the intelligent joint rehabilitation brace. The model of the additional structure is a sheet model, including a main structure and a connecting structure. The main structure has structural units with the same structural form as the structure form. 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 preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to claim 1, characterized in that, In the 4D printing, first use PLA material 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, place the printed part at 60 °C - 70 °C to make it deform and form a three-dimensional structure.

9. The preparation method of the intelligent joint rehabilitation brace based on 4D printing and customizable force feedback according to claim 1, characterized in that, Before the heat treatment deformation in the 4D printing, arrange the sensing circuit lines on the printed part with a conductive tape. After the heat treatment deformation, install a sensor module on the three-dimensional structure to jointly form a sensing circuit with the sensing circuit lines to monitor the force feedback of the brace. In this stage, use a conductive cloth tape and a pressure sensor 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, For implementing the method according to any one of claims 1 - 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 parameter and the force feedback, and the required force feedback for rehabilitation; the model display module is used to display the sheet model of the brace obtained after being adjusted by the force feedback adjustment module, and the effect after 4D printing.

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