Mortise and tenon type 3D printing multi-material composite bionic ankle foot orthosis

Abstract

The invention discloses a tenon-and-mortise type 3D printing multi-material composite bionic ankle-foot orthosis, which belongs to the technical field of rehabilitation engineering and additive manufacturing, and comprises a tibia supporting part, a tenon-and-mortise type locking structure, an ankle joint part, a sole supporting part and an ankle-foot orthosis bandage, the tibia supporting part is of a semi-arc surface structure, the section of the tibia supporting part is gradually reduced from top to bottom, and the tibia supporting part is formed by compositely printing an inner side flexible attaching layer and an outer side rigid layer; the tibia supporting part, the ankle joint part and the sole supporting part are sequentially connected in a transition fit and locking manner through a mortise and tenon locking structure; the ankle joint part is of an approximately L-shaped cambered surface wrapping structure, and a bionic skin microstructure contact layer is arranged on the inner side of the ankle joint part; the sole supporting part is of a U-shaped cambered surface structure, and the section of the sole supporting part is gradually increased from inside to outside; a bionic octopus sucker is arranged on the bottom surface of the inner side, and sole anti-skid lines are arranged on the bottom surface of the outer side; the ankle-foot orthosis bandage is used for fixing the shank and the foot respectively. In conclusion, the invention has great application value in the fields of rehabilitation engineering and medical instruments.

Description

Technical Field

[0001] This invention belongs to the field of rehabilitation engineering and additive manufacturing technology, specifically relating to a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis. Background Technology

[0002] Ankle-foot orthoses (AFOs) are commonly used orthopedic rehabilitation devices in clinical practice. They are mainly used to improve the motor function of the foot and ankle. They are suitable for patients with stroke, cerebral palsy, spinal cord injury, and other conditions, as well as for rehabilitation after foot and ankle fracture surgery and as an adjunct treatment for conditions such as congenital clubfoot. Their core function is to help patients restore normal gait, reduce joint load, and lower the risk of secondary injury by limiting abnormal movement and providing support and stability.

[0003] However, with the development of rehabilitation medicine and manufacturing technology, traditional ankle and foot orthoses have gradually exposed many technical bottlenecks. Traditional ankle and foot orthoses have many technical limitations. In terms of materials, they mostly use a single rigid material, such as stainless steel or carbon fiber plate, or a single flexible material, such as silicone or elastic fabric. While rigid materials can provide stable support, they have poor fit and are heavy. Long-term wear can easily lead to problems such as skin pressure and poor blood circulation. While flexible materials improve comfort, they lack support strength and are difficult to effectively correct abnormal foot and ankle postures. They cannot meet the dual requirements of "support stability" and "wearing comfort".

[0004] In terms of connection structure, existing multi-component orthotics mostly rely on screws, clips or adhesives for connection. Mechanical connections are prone to loosening and falling off due to long-term gait impact, and stress concentration is easily generated during assembly, which reduces the overall structural strength of the orthotics and affects the service life and safety of use of the orthotics.

[0005] In terms of personalized fitting, due to the complex anatomical structure of the foot and ankle, there are significant individual differences in bone morphology, muscle tension, and type of movement disorder among different patients. Customized orthotics mostly rely on manual production, which has problems such as low production efficiency, high cost, and difficulty in accurately controlling material distribution and structural parameters.

[0006] In terms of biomimetic performance and functional integration, the human foot and ankle have complex biomimetic movement characteristics. Existing orthotics are mostly rigid constraints or simple elastic support structures, which cannot simulate the movement trajectory and mechanical transmission law of normal foot and ankle, resulting in stiff and unnatural gait for patients. At the same time, single materials and traditional structural designs are also difficult to achieve the functional integration of "support-cushioning-breathability-lightweight", which cannot meet the diverse needs of patients in daily activities.

[0007] As 3D printing technology is increasingly applied to orthotic manufacturing, multi-material composite 3D printing technology has further broken through the performance limitations of single materials. Through the synergistic distribution of materials with different stiffness and elasticity, it is expected to achieve a balance between support and comfort. Mortise and tenon structures, as a classic connection method in traditional Chinese woodworking, have the characteristics of "no nails or glue, self-locking structure, and smooth mechanical transmission." They achieve a stable connection through the interlocking of components, eliminating the need for additional fasteners, avoiding stress concentration, improving the overall integrity and reliability of the structure, and being easy to disassemble, environmentally friendly, and durable. However, currently, there is no existing technology that integrates mortise and tenon connection structures, multi-material composite 3D printing, and foot and ankle bionic design. There is an urgent need for an ankle and foot orthosis that can take into account personalized fit, structural reliability, balance of support and comfort, and excellent bionic performance to meet the actual needs of clinical rehabilitation treatment. Summary of the Invention

[0009] To address the problems existing in the aforementioned technical fields, a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis is provided to achieve a precise balance between "support stability" and "wearing comfort," improve the reliability and service life of structural connections, and at the same time simulate the bionic movement characteristics of the human foot and ankle to optimize the naturalness of the patient's gait and functional diversity.

[0010] The technical solution adopted in this invention is as follows:

[0011] A mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis includes: tibial support part 1, mortise and tenon type locking structure 2, ankle joint part 3, foot support part 4, and ankle and foot orthosis strap 5.

[0012] The tenon-and-mortise locking structure 2 includes an upper tenon-and-mortise locking structure 201 for the ankle joint and a lower tenon-and-mortise locking structure 202 for the ankle joint.

[0013] The ankle joint upper tenon and mortise locking structure 201 includes a tibial support tenon and mortise protrusion structure 102 and an ankle joint upper tenon and mortise protrusion structure 301 that are mutually transitioned and locked together.

[0014] The ankle joint lower tenon and mortise locking structure 202 includes an ankle joint lower tenon and mortise protrusion structure 304 and a foot support tenon and mortise protrusion structure 401 that are mutually transitioned and locked together.

[0015] The tibial support part 1 has a semi-circular arc surface structure, and the cross section gradually decreases from top to bottom; both sides are provided with tibial support part binding fixation sleeves 101, and the lower end is provided with a tibial support part tenon protrusion structure 102.

[0016] The ankle joint portion 3 has a near-L-shaped arc-shaped wrapping structure, which is composed of an upper curved surface 302 of the ankle joint portion and a lower arc-shaped guide surface 303 of the ankle joint portion.

[0017] The upper end of the upper curved surface 302 of the ankle joint is provided with an upper tenon and tenon protrusion structure 301 of the ankle joint, and the outer end of the lower arc-shaped guide surface 303 of the ankle joint is provided with a lower tenon and tenon protrusion structure 304 of the ankle joint.

[0018] The foot support part 4 has a U-shaped arc surface structure, and the cross-section gradually increases from the inside to the outside.

[0019] The foot support part 4 is provided with foot support part strap fixing sleeve 402 on both sides, and the inner bottom surface of the foot support part is provided with foot support part bionic octopus suction cup 403, and the outer bottom surface of the foot support part is provided with foot support part anti-slip texture 404.

[0020] The ankle-foot orthotic strap 5 includes a tibial support strap 50 and a plantar support strap 51;

[0021] The tibial support strap 50 connects to the tibial support strap fixing sleeves 101 on both sides, and the foot support strap 51 connects to the foot support strap fixing sleeves 402 on both sides.

[0022] The interlocking and locking tenon structure is composed of staggered dovetail tenon units 6.

[0023] The outer wall of the tenon unit 6 is provided with fine anti-slip textures with a depth of 0.3-0.5mm and a spacing of 1-2mm; and a rectangular slot is provided in the middle of the outer wall of the tenon unit 6, and an interference strip 60 is inserted into the rectangular slot of the tenon unit 6 to transition and cooperate with each other.

[0024] The anti-slip texture 404 of the foot support part 4 is integrally formed by additive manufacturing of ceramic particle reinforced rubber matrix composite material; the anti-slip texture is one or more combinations of cross grid texture, strip anti-slip texture or wave anti-slip texture, the texture depth is 0.8-2mm and the texture spacing is 2-5mm.

[0025] The biomimetic octopus suction cup 403 on the inner side of the foot support part 4 is arranged in an array of multiple columnar flexible protrusions.

[0026] The main body of the foot support part 4 adopts a layered composite structure, which is formed by the inner buffer layer and the outer bearing layer through a multi-material melt deposition molding process; the inner buffer layer is made of TPU-95A flexible material, and the outer bearing layer is made of carbon fiber reinforced polycarbonate material.

[0027] The ankle joint 3 allows the user's ankle to flex and extend within a range of ±15°; the ankle joint 3 has arc-shaped guide surfaces on both sides, and the radius of curvature R of the guide surfaces is 20-40mm.

[0028] The inner side of the ankle joint 3 is provided with a biomimetic skin microstructure contact layer, wherein the biomimetic skin microstructure is one or more combinations of millimeter-level protrusion array, honeycomb-shaped depression structure or biomimetic dermal texture structure.

[0029] The ankle joint 3 is printed using carbon fiber reinforced thermoplastic polyurethane composite material through fused deposition modeling technology; the root of the tenon unit 6 is provided with a stress transition rounded corner with a radius of 15-20mm, and the root wall thickness is increased by 20%-40% compared with the tenon unit 6.

[0030] The tibial support 1 includes an inner flexible bonding layer and an outer rigid support layer; the interference fit insert 60 has a cuboid structure and an interference fit of 0.15-0.25 mm.

[0031] This invention provides a mortise and tenon joint 3D-printed multi-material composite bionic ankle-foot orthosis, belonging to the fields of rehabilitation engineering and additive manufacturing technology. It includes: a tibial support portion, a mortise and tenon joint locking structure, an ankle joint portion, a foot support portion, and ankle-foot orthotic straps. The tibial support portion has a semi-circular arc surface structure with a gradually decreasing cross-section from top to bottom, and is composite-printed from an inner flexible adhesive layer and an outer rigid layer. The tibial support portion, ankle joint portion, and foot support portion are sequentially connected and locked together by the mortise and tenon joint locking structure. The ankle joint portion has a near-L-shaped arc surface wrapping structure, with a bionic skin microstructure contact layer on its inner side. The foot support portion has a U-shaped arc surface structure with a gradually increasing cross-section from the inside to the outside; its inner bottom surface has a bionic octopus suction cup, and its outer bottom surface has anti-slip textures. The ankle-foot orthotic straps are used for fixation of the lower leg and foot. In summary, this invention has significant application value in the fields of rehabilitation engineering and medical devices.

[0032] In summary, the mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis provided by this invention has the following beneficial effects:

[0033] 1) Based on the innovation of multi-material composite molding, FDM multi-material co-extrusion 3D printing technology is adopted to customize exclusive material combinations according to the functional requirements of different parts of the orthodontic device, so as to achieve a precise match between flexible fit and rigid support, ensuring both wearing comfort and structural support strength, and effectively improving the biomechanical performance and adaptability of the product.

[0034] 2) Based on biomimetic structural optimization and innovation, it integrates multi-dimensional biomimetic designs such as the biomimetic skin microstructure on the inner side of the ankle joint, the biomimetic octopus suction cup of the foot support part, and the arc-shaped motion guide surface. It accurately adapts to the characteristics of human skin and the natural movement trajectory of the ankle, significantly improving the fit and biomimetic movement, while enhancing breathability and solving the problems of stuffiness and poor fit of traditional orthotics.

[0035] 3) Based on the innovative mortise and tenon connection design, a detachable mortise and tenon unit and interference fit strip connection structure are adopted to achieve tool-free disassembly and assembly, greatly improving the convenience of maintenance; further enhancing the connection stability, avoiding loosening of parts during use, extending the product service life, and solving the pain points of cumbersome maintenance and unstable connection of traditional orthotics.

[0036] 4) Additive manufacturing enables personalized and efficient customization to meet diverse needs. It allows for precise customization of product size and shape based on the anatomical structure of different patients, addressing the pain points of traditional orthotics' strong universality and poor adaptability. It achieves multi-dimensional synergistic optimization in biomechanical performance, wearing comfort, and service life, demonstrating significant technological advancement. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the overall structure of a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis of the present invention;

[0038] Figure 2 This is a schematic diagram of the three-dimensional structure of the tibial support part of a tenon-and-mortise type 3D printed multi-material composite bionic ankle and foot orthosis of the present invention;

[0039] Figure 3 This is a schematic diagram of the mortise and tenon locking structure installation method of a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis of the present invention;

[0040] Figure 4 This is a three-dimensional structural diagram of the ankle joint of a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to the present invention;

[0041] Figure 5 This is a schematic diagram of the specific structure of the foot support part of a tenon-and-mortise type 3D printed multi-material composite bionic ankle and foot orthosis of the present invention;

[0042] Figure 6 This is a schematic diagram of the specific structure of the anti-slip texture of the foot support part of the mortise and tenon joint type 3D printed multi-material composite bionic ankle and foot orthosis of the present invention;

[0043] Figure 7 This is a schematic diagram of the specific structure of the mortise and tenon unit of a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis of the present invention.

[0044] In the attached diagram:

[0045] 1. Tibial support; 101. Tibial support bandage fixation sleeve; 102. Tibial support tenon and mortise protrusion structure;

[0046] 2. Mortise and tenon locking structure; 201. Upper mortise and tenon locking structure of the ankle joint; 202. Lower mortise and tenon locking structure of the ankle joint;

[0047] 3. Ankle joint; 301. Upper tenon and mortise protrusion structure of the ankle joint; 302. Upper curved surface of the ankle joint; 303. Lower arc-shaped guide surface of the ankle joint; 304. Lower tenon and mortise protrusion structure of the ankle joint;

[0048] 4. Foot support section; 401. Tenon and mortise protrusion structure of the foot support section; 402. Strap fixing sleeve of the foot support section; 403. Bionic octopus suction cup of the foot support section; 404. Anti-slip texture of the foot support section;

[0049] 5. Ankle-foot orthotic strap; 50. Tibial support strap; 51. Plantar support strap;

[0050] 6. Mortise and tenon unit; 60. Interference fitting. Detailed Implementation

[0051] Example 1

[0052] A mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis includes: tibial support part 1, mortise and tenon type locking structure 2, ankle joint part 3, foot support part 4, and ankle and foot orthosis strap 5.

[0053] The tenon-and-mortise locking structure 2 includes an upper tenon-and-mortise locking structure 201 for the ankle joint and a lower tenon-and-mortise locking structure 202 for the ankle joint.

[0054] The ankle joint upper tenon and mortise locking structure 201 includes a tibial support tenon and mortise protrusion structure 102 and an ankle joint upper tenon and mortise protrusion structure 301 that are mutually transitioned and locked together.

[0055] The ankle joint lower tenon and mortise locking structure 202 includes an ankle joint lower tenon and mortise protrusion structure 304 and a foot support tenon and mortise protrusion structure 401 that are mutually transitioned and locked together.

[0056] The tibial support 1 has a semi-circular arc surface structure, and the cross section gradually decreases from top to bottom; both sides of its front end are provided with tibial support strap fixing sleeves 101, and its lower end is provided with a tibial support tenon protrusion structure 102.

[0057] The ankle joint portion 3 has a near-L-shaped arc-shaped wrapping structure, which is composed of an upper curved surface 302 of the ankle joint portion and a lower arc-shaped guide surface 303 of the ankle joint portion.

[0058] The upper end of the upper curved surface 302 of the ankle joint is provided with an upper tenon and tenon protrusion structure 301 of the ankle joint, and the outer end of the lower arc-shaped guide surface 303 of the ankle joint is provided with a lower tenon and tenon protrusion structure 304 of the ankle joint.

[0059] The foot support part 4 has a U-shaped arc surface structure, and the cross-section gradually increases from the inside to the outside.

[0060] The upper ends of both sides of the foot support part 4 are provided with foot support strap fixing sleeves 402, the inner bottom surface of which is provided with a foot support bionic octopus suction cup 403, and the outer bottom surface of which is provided with a foot support anti-slip texture 404.

[0061] The ankle-foot orthotic strap 5 includes a tibial support strap 50 and a plantar support strap 51;

[0062] The tibial support strap 50 connects to the tibial support strap fixing sleeves 101 on both sides, and the foot support strap 51 connects to the foot support strap fixing sleeves 402 on both sides.

[0063] See appendix Figure 7 The interlocking mortise and tenon structure is composed of staggered dovetail tenon and tenon units 6, and the clamping angle of the dovetail tenon and tenon unit 6 (isosceles trapezoidal cross-section) is... The calculation formula is shown in the following formula [1]:

[0064] [1]

[0065] in, The length of the top side of mortise and tenon unit 6. The length of the bottom side of mortise and tenon unit 6. The height of the mortise and tenon unit 6.

[0066] The outer wall of the tenon unit 6 is provided with fine anti-slip textures with a depth of 0.3-0.5mm and a spacing of 1-2mm; the tenon units 6 that fit together achieve initial pre-tightening through the interlocking effect of the anti-slip textures, and the gap between them is no more than 0.1mm.

[0067] A rectangular slot is provided in the middle of the outer wall of the tenon unit 6. An interference strip 60 is inserted into the rectangular slot of the tenon unit 6 to achieve double fixing and force transmission between the components, and further realize the stable connection between the components.

[0068] The anti-slip texture 404 of the foot support part 4 is integrally formed by additive manufacturing of ceramic particle reinforced rubber matrix composite material; the anti-slip texture is one or more combinations of cross grid texture, strip anti-slip texture or wave anti-slip texture, which are regularly arranged along the entire area of ​​the anti-slip and wear-resistant layer or the key stress area of ​​the sole. The texture depth is 0.8-2mm and the texture spacing l2 is 2-5mm. By increasing the contact friction coefficient with the ground, the anti-slip performance and wear resistance during walking are improved, and the safety of use is ensured.

[0069] The biomimetic octopus suction cup 403 on the inner side of the foot support part 4 is arranged in a double-sided symmetrical array of multiple columnar flexible protrusions. It enhances the tightness of the fit between the foot support part 4 and the skin through adsorption, while inhibiting relative slippage during wearing, thus improving wearing stability and fit comfort.

[0070] The main body of the foot support part 4 adopts a layered composite structure, which is formed by the inner buffer layer and the outer bearing layer through a multi-material fused deposition molding process; the inner buffer layer is used to absorb foot pressure and buffer the impact of walking; the outer bearing layer bears the weight of the foot and maintains gait stability.

[0071] The ankle joint 3 is configured to restrict the lateral displacement of the user's ankle along a direction perpendicular to the plane of motion, allowing the ankle to flex and extend within a range of ±15°;

[0072] The ankle joint 3 has arc-shaped guide surfaces on both sides, with a radius of curvature R of 20-40mm, and the ankle flexion angle... The calculation formula is shown in the following formula [2]:

[0073] [2]

[0074] The inner side of the ankle joint 3 is provided with a biomimetic skin microstructure contact layer. The biomimetic skin microstructure is one or more combinations of millimeter-level protrusion array, honeycomb-shaped depression structure or biomimetic dermal texture structure. Among them, the protrusion height h1 of the millimeter-level protrusion array is 0.5-2mm and the protrusion spacing l3 is 1-3mm. The texture depth of the biomimetic dermal texture structure is 0.2-0.8mm and the texture spacing is 0.8-2mm. The size parameters of the biomimetic microstructure are adapted to the contact characteristics of human skin, improving the fit, comfort and breathability.

[0075] The ankle joint 3 is printed using carbon fiber reinforced thermoplastic polyurethane composite material through fused deposition modeling technology; the root of the tenon unit 6 is provided with a stress transition rounded corner with a radius of 15-20mm, and the root wall thickness is increased by 20%-40% compared with the tenon unit 6.

[0076] The tibial support 1 is integrally printed using multi-material fused deposition modeling technology, forming a composite double-layer structure in the thickness direction, including an inner flexible adhesive layer and an outer rigid support layer. The inner flexible adhesive layer is in direct contact with the human tibia, and the adaptability of the flexible material improves wearing comfort and avoids skin pressure and friction damage. The outer rigid support layer provides stable structural support, effectively corrects abnormal foot and ankle postures, and achieves the dual requirements of "comfortable fit" and "stable support".

[0077] The interference insert 60 has a cuboid structure and is integrally formed by additive manufacturing using medical-grade 3D printed thermoplastic polyester material (such as PLA). Its interference fit is 0.15-0.25mm.

[0078] This invention discloses a mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis, the specific preparation method and assembly steps of which are as follows:

[0079] S1. First, perform 3D model preprocessing: The completed 3D model of the bionic ankle and foot orthosis is divided into the structure of tibial support part 1, ankle joint part 3, foot support part 4, and interference strip 60. The tibial support part 1 and foot support part 4 are set to dual-material or multi-material composite printing mode, while the ankle joint part 3 and interference strip 60 are set to single-material printing mode.

[0080] S2. Material of tibial support 1: Its flexible bonding layer is made of TPU-95A flexible material, and its outer rigid support layer is made of PA engineering plastic;

[0081] S3. Material of ankle joint 3: The entire structure is made of carbon fiber reinforced thermoplastic polyurethane composite material (TPU-CF).

[0082] S4. Material of foot support part 4: The biomimetic octopus suction cup 403 of the foot support part is made of TPU-95A flexible material; the inner layer of the main body of the foot support part 4 is made of TPU-95A flexible material; the outer layer of the main body is made of carbon fiber reinforced polycarbonate material (PC-CF); the anti-slip texture 404 of the foot support part is made of ceramic particle reinforced rubber base composite material.

[0083] S5. Material of the interference fit insert 60: It is made entirely of PLA polylactic acid material;

[0084] S6. Set the printing parameters for each component according to the selected materials, and print each component as a single piece;

[0085] S7. Finished Product Assembly and Debugging: After each component is printed, molded, cooled and set, the tibial support part 1, ankle joint part 3, and foot support part 4 are assembled and connected in sequence through tenon and mortise units 6. Adjustable straps are installed on the strap fixing sleeves of the tibial support part 1 and the foot support part 4. By adjusting the tightness of the straps, the orthosis fits tightly with the human lower limbs, while ensuring wearing comfort, and the overall assembly is completed.

[0086] The ankle-foot orthosis provided by this invention achieves performance customization of different functional areas through multi-material composite 3D printing technology, taking into account wearing comfort, structural support strength and bionic movement. In addition, the mortise and tenon connection structure with detachable locking blocks greatly improves the ease of maintenance of the product. It is suitable for daily orthopedic and rehabilitation assistance for patients with lower limb motor dysfunction and has great technological advancement and application value in the fields of rehabilitation engineering and personalized medical devices.

Claims

1. A mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis, characterized in that, include: Tibial support (1), tenon-and-mortise locking structure (2), ankle joint (3), foot support (4), ankle-foot orthotic strap (5); The tenon-and-mortise locking structure (2) includes an upper tenon-and-mortise locking structure (201) at the ankle joint and a lower tenon-and-mortise locking structure (202) at the ankle joint. The ankle joint upper tenon and mortise locking structure (201) includes a tibial support tenon and mortise protrusion structure (102) and an ankle joint upper tenon and mortise protrusion structure (301) that are mutually transitioned and locked together. The ankle joint lower tenon locking structure (202) includes an ankle joint lower tenon protrusion structure (304) and a foot support tenon protrusion structure (401) that are mutually transitionally fitted and locked together. The tibial support (1) has a semi-circular arc structure, and the cross section gradually decreases from top to bottom; both sides are provided with tibial support strap fixing sleeves (101), and the lower end is provided with a tibial support tenon protrusion structure (102). The ankle joint (3) has a near-L-shaped arc-shaped wrapping structure, consisting of an upper curved surface (302) of the ankle joint and a lower arc-shaped guide surface (303) of the ankle joint; The upper end of the upper curved surface (302) of the ankle joint is provided with an upper tenon protrusion structure (301) of the ankle joint, and the outer end of the lower arc-shaped guide surface (303) of the ankle joint is provided with a lower tenon protrusion structure (304). The foot support part (4) has a U-shaped arc surface structure, and the cross section gradually increases from the inside to the outside; The foot support part (4) is provided with foot support part strap fixing sleeves (402) on both sides, and the inner bottom surface of the foot support part is provided with a foot support part bionic octopus suction cup (403), and the outer bottom surface of the foot support part is provided with a foot support part anti-slip texture (404). The ankle-foot orthotic strap (5) includes a tibial support strap (50) and a plantar support strap (51). The tibial support strap (50) connects to the tibial support strap fixing sleeves (101) on both sides, and the foot support strap (51) connects to the foot support strap fixing sleeves (402) on both sides.

2. The mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 1, characterized in that: The interlocking and locking tenon structure is composed of staggered dovetail tenon units (6); The outer wall of the tenon unit (6) is provided with fine anti-slip texture with a depth of 0.3-0.5mm and a spacing of 1-2mm; and a rectangular slot is provided in the middle of the outer wall of the tenon unit (6), and an interference strip (60) is inserted into the rectangular slot of the tenon unit (6) to transition and cooperate with each other.

3. The mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 2, characterized in that: The anti-slip pattern (404) of the foot support part (4) is integrally formed by additive manufacturing of ceramic particle reinforced rubber matrix composite material; the anti-slip pattern is one or more combinations of cross grid pattern, strip anti-slip pattern or wave anti-slip pattern, the pattern depth is 0.8-2mm, and the pattern spacing l2 is 2-5mm.

4. The mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 3, characterized in that: The biomimetic octopus suction cup (403) on the inner side of the foot support part (4) is arranged in an array of multiple columnar flexible protrusions.

5. The mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 4, characterized in that: The main body of the foot support part (4) adopts a layered composite structure, which is formed by the inner buffer layer and the outer bearing layer through a multi-material melt deposition molding process; the inner buffer layer is made of TPU-95A flexible material, and the outer bearing layer is made of carbon fiber reinforced polycarbonate material.

6. The mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 5, characterized in that: The ankle joint (3) allows the user's ankle to flex and extend within a range of ±15°; the ankle joint (3) has arc-shaped guide surfaces on both sides, with a radius of curvature R of 20-40 mm. The inner side of the ankle joint (3) is provided with a biomimetic skin microstructure contact layer, wherein the biomimetic skin microstructure is one or more of the following: millimeter-level protrusion array, honeycomb-shaped depression structure, or biomimetic dermal texture structure.

7. A mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 5 or 6, characterized in that: The ankle joint (3) is printed using carbon fiber reinforced thermoplastic polyurethane composite material through melt deposition molding technology; the root of the tenon unit (6) is provided with a stress transition rounded corner with a radius of 15-20mm, and the root wall thickness is increased by 20%-40% compared with the tenon unit (6).

8. The mortise and tenon type 3D printed multi-material composite bionic ankle and foot orthosis according to claim 7, characterized in that: The tibial support (1) includes an inner flexible bonding layer and an outer rigid support layer; the interference strip (60) is a cuboid structure with an interference fit of 0.15-0.25 mm.

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