A human-friendly old-age-care walking aid and a lightening method thereof

Abstract

This invention discloses a user-friendly elderly mobility aid and its lightweighting method, belonging to the field of medical rehabilitation equipment technology. The lightweighting method is based on anti-rollover mechanical constraints and SIMP variable density topology optimization, constructing a critical mass global constraint. Through multi-condition loading, sensitivity iteration, and feature reconstruction, the legs are made into a variable cross-section porous truss, achieving precise weight reduction and preventing rollover. The mobility aid includes a topology-optimized main body, a walking wheel set, a spring-hydraulic composite shock absorption device, and an actuator module. The main body adopts a two-dimensional cutting and three-dimensional assembly process. The shock absorption device compensates for structural damping and attenuates high-frequency vibrations, and the actuator module realizes mode switching and mechanical limit load bearing. This invention solves the problems of excessive weight, easy rollover, and high-frequency hand vibration in traditional robots, balancing lightweight, high rigidity, safety, and user-friendliness. It has low manufacturing cost, is easy to mass-produce, and is suitable for assisting elderly people with mobility.

Description

Technical Field

[0001] This invention belongs to the field of medical rehabilitation assistive devices and robotics technology, specifically relating to a humanized elderly mobility aid and its lightweighting method. Background Technology

[0002] With the accelerating aging of the global population, the demand for intelligent devices that can assist the elderly in independent travel, provide daily care, and ensure safety is becoming increasingly urgent. As a new type of assistive device that integrates active assistance in walking, seated mobility, and safety protection, the elderly companion robot can effectively extend their activity radius, improve their self-care ability, and has significant social application value.

[0003] However, existing elderly-assisting robots suffer from significant technical shortcomings in terms of both lightweight design and shock absorption. On the one hand, to ensure load-bearing safety, traditional devices often use heavy, solid profiles, resulting in excessive weight, difficulty in pushing, and short battery life. Blindly reducing weight through conventional methods can easily break the critical boundary of the machine's center of gravity for preventing tipping, leading to a risk of overturning when the elderly lean asymmetrically, creating a physical paradox between lightweight design and tipping safety. On the other hand, pursuing extreme lightweighting by hollowing out the internal structure inevitably causes a precipitous drop in the system's inherent structural damping. The high-rigidity, porous frame transmits minor road bumps to the human body without attenuation, causing severe secondary defects such as "high-frequency hand vibration," which conventional single mechanical spring shock absorbers cannot mitigate.

[0004] Therefore, there is an urgent need for a scientific lightweighting method that can integrate strict anti-fall mechanical constraints into the underlying algorithm, and provide humanized equipment that can provide targeted soft and hard co-compensation after structural weight reduction induces new defects in structural damping loss. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a humanized elderly mobility aid and its lightweight method in response to the shortcomings of the prior art. This invention addresses the technical problems that currently, blindly reducing weight can easily lead to instability and tipping over, as well as the loss of structural damping and increased transmission of high-frequency vibrations caused by lightweight porous structures.

[0006] The present invention adopts the following technical solution: A method for lightweighting and making humane elderly mobility aids includes the following steps: S1. Static and dynamic modeling of the elderly companion robot under extreme interactive conditions is performed, an anti-rollover force mechanical model is established, the critical mass lower limit threshold for maintaining the whole machine from overturning under extreme interactive conditions is calculated, and the critical mass lower limit threshold is converted into a global volume fraction constraint condition in the topology optimization algorithm. S2. Define the front and rear outriggers of the robot body as the initial design domain, extract loads for typical operating conditions and convert them into combined bending and torsion loads, and apply the combined bending and torsion loads and displacement boundary conditions to the initial design domain. S3. Construct a SIMP variable density topology optimization mathematical model with the objective function of minimizing the overall structural flexibility of the initial design domain, and introduce a material interpolation function to nonlinearly penalize the pseudo density of the elements. S4. Under the constraints of the global volume fraction, perform sensitivity analysis on the objective function, and use the optimality criterion method to update variables and iteratively solve the problem to obtain the material pseudo-density distribution cloud map of each unit in the initial design domain. S5. Set a density stripping threshold, remove redundant material units in low-stress areas that are close to 0 according to the material pseudo-density distribution cloud map, retain the force transmission skeleton in high-stress areas that are close to 1, and reconstruct the front leg and rear leg into a variable cross-section porous hollow truss structure.

[0007] Preferably, in step S1, the extreme interaction conditions include uphill and downhill conditions under the maximum allowable slope and force conditions under the user's unilateral asymmetrical leaning. The entire machine and the human body are regarded as a mechanically coupled system. By establishing the torque balance equation between the system's center of gravity and the wheel contact point, under the critical rollover state, assuming that the ground vertical support force of the unloaded side wheel is just close to zero, by establishing the extreme value relationship between the stabilizing torque generated by gravity and the overturning torque generated by the lateral thrust, the minimum safe mass that the entire machine must maintain is solved in reverse. The minimum safe mass is used as the lower limit threshold of the critical mass. The critical mass lower limit threshold is irreversibly transformed into an absolute global volume fraction constraint in the topology optimization algorithm. ,in, The maximum volume of material that can be retained.

[0008] Preferably, in step S2, the three working conditions of assisted walking push-pull, static riding, and support to stand up are converted into combined bending and torsion qualitative loads and boundary conditions acting on the design domain. The boundary conditions include the bottom fixed support boundary conditions; the combined bending and torsion qualitative loads include the pedal lever force and armrest pressure, the main push rod force, the outrigger resistance, the trunk mass loading, the load and seat mass loading, and the armrest reaction force.

[0009] Preferably, in step S3, the specific mathematical model for SIMP variable density topology optimization is as follows: The material interpolation function is:

[0010] The objective function is:

[0011] in, For the first The elastic modulus of each unit For the first The pseudo density of each unit As a penalty factor, The elastic modulus of a solid material. The minimum elastic modulus is set to avoid the singularity of the stiffness matrix in the finite element method; For the overall structural flexibility, The total displacement vector, The overall stiffness matrix, For element displacement vectors, The initial stiffness matrix of the element. The total number of units.

[0012] Preferably, in step S4, during the sensitivity analysis and iterative solution process, a grid independence filtering mechanism based on node distance is introduced. The sensitivity is corrected by calculating the weighted average of the pseudo-densities of the central cell and its neighboring cells, so as to suppress the checkerboard effect and grid dependence in the evolution of lightweight materials.

[0013] Preferably, in step S5, the density stripping threshold is set to a specific value within the range [0.2, 0.4], and units with pseudo-density less than the density stripping threshold are regarded as redundant material units in the low-stress area and are eliminated in a thorough manner. When reconstructing the variable cross-section multi-hole hollow truss structure, the limitation of the uniform cross-section solid structure is broken, the continuous outer force-bearing frame is retained along the main stress transmission path, the internal low stress area is completely hollowed out to form a through-type weight-reducing hole, and at the large bending moment node, cross force transmission stiffeners are added between the adjacent through-type weight-reducing holes along the main tensile and compressive stress direction. During engineering 3D reconstruction, the generated complex porous morphology is decomposed into a configuration combining 2D plate topological cutting and 3D lateral assembly: For the front outrigger, two parallel and opposite front outrigger side plates are used as the main load-bearing components. The continuous outer force-bearing frame, through-type weight-reduction hole and cross force-transmitting rib plate are precisely preserved in the plane of the front outrigger side plate. The two front outrigger side plates are horizontally connected and welded together by the top front outrigger connecting plate and the bottom front outrigger base plate. The rear outrigger is assembled by clamping two rear outrigger side plates with the same porous features. At the high-stress hinge joint, a large-diameter hollow cylindrical connecting block is used for lateral torsional support, and the bottom end is sealed by a rear outrigger connecting plate.

[0014] Another technical solution of the present invention is a user-friendly elderly mobility aid, comprising: The fuselage body includes a front outrigger and a rear outrigger, both of which are variable cross-section porous truss structures prepared by the lightweight method. The walking wheel set is installed at the bottom of the main body of the machine; A composite shock absorption device is connected in series between the lower end of the front support leg and the corresponding walking wheel set; The variable cross-section multi-hole hollow truss structure has a continuous outer force-bearing frame, a through-type weight-reducing hole, and cross force-transmitting stiffeners set between adjacent through-type weight-reducing holes. The composite damping device is used to dynamically compensate for the decrease in the inherent damping of the whole system structure caused by the variable cross-section porous truss structure, and to attenuate the high-frequency vibration of the road surface transmitted by the high-rigidity porous frame.

[0015] Preferably, the composite shock absorption device is a spring-hydraulic composite shock absorber, which is externally coupled to the main body of the fuselage through a front wheel mounting bracket, connecting rod, fixed seat and connecting frame; The composite shock absorber has a piston rod, spring, oil reservoir cylinder, piston, bottom valve and compensation chamber arranged coaxially inside; The oil reservoir cylinder has an upper chamber and a lower chamber. The piston is located inside the oil reservoir cylinder and divides the oil reservoir cylinder into the upper chamber and the lower chamber. The piston rod is connected to the piston, and the spring is sleeved outside the piston rod. The bottom valve is located at the bottom of the oil storage cylinder, and the compensation chamber is connected to the bottom valve; The spring is used to absorb and attenuate the low-frequency, long-stroke impact energy during obstacle crossing. The oil reservoir is sealed with hydraulic oil. The viscous fluid friction damping generated when the hydraulic oil is squeezed by the piston and flows through the tiny pores of the bottom valve absorbs and attenuates the high-frequency fine vibrations transmitted non-destructively by the variable cross-section porous hollow truss structure.

[0016] Preferably, both the front support leg and the rear support leg adopt a modular configuration that combines two-dimensional plate cutting with three-dimensional lateral splicing; The front support leg consists of two parallel and opposite front support leg side plates as the main load-bearing components. The two front support leg side plates are laterally connected and assembled through a top front support leg connecting plate and a bottom front support leg base plate. The rear support leg consists of two parallel and opposite rear support leg side plates as the main load-bearing components. The two rear support leg side plates are laterally supported and torsion-resistant at the high-stress hinge joints by hollow cylindrical connecting blocks. The bottom end is laterally assembled and closed by the rear support leg connecting plate. Both the front support leg side plate and the rear support leg side plate are hollowed out in two-dimensional planes with continuous outer force-bearing frame, through-type weight-reducing holes and cross force-transmitting ribs, which together form a box-shaped three-dimensional multi-hole truss after being horizontally assembled.

[0017] Preferably, it also includes an actuator module mounted on the fuselage body; The actuator module is a macro-control and execution combined package module, which includes a three-pole linkage posture change mechanism for smooth switching of the center of gravity between the assisted walking and wheelchair transport modes, and a mechanical limiting seat mechanism that relies on the internal mechanical dead point for physical limiting and load bearing when unfolded to the horizontal set position.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: A lightweight method for humane elderly mobility aids uses the critical anti-tipping mass as a hard boundary condition for topology optimization. By establishing a mechanical model under extreme working conditions, the minimum safe mass is solved in reverse, ensuring that the lightweight structure will not overturn under extreme stress. This solves the most feared safety hazard of tipping over for elderly people using mobility aids in nursing homes. Simultaneously, the SIMP variable density method combined with multi-condition bending and torsional loads automatically identifies and retains high-stress force transmission paths and eliminates redundant materials. This not only achieves extreme structural lightweighting, reducing the resistance for elderly people to push the device, but also ensures the optimal distribution of structural stiffness through mathematical modeling, avoiding structural failure caused by excessive weight reduction. It provides a precise digital model basis for subsequent manufacturing, significantly improving R&D efficiency and product safety.

[0019] Furthermore, by treating the human-machine coupling system as a whole, the critical state where the unloading side wheel support force is zero is precisely calculated using the moment balance equation, thus deriving the insurmountable lower mass limit. This approach, which transforms physical safety thresholds into algorithmic constraints, gives the optimization process clear physical meaning and safety orientation, avoiding the lightweight but unstable structures that might result from purely mathematical optimization. Ensuring that the final truss structure possesses inherent anti-rollover capability under any permissible usage scenario greatly enhances product reliability and user trust, a key technical feature for protecting the lives of elderly users.

[0020] Furthermore, by transforming the complex actual stresses into combined bending and torsional loads identifiable by finite element analysis, the robustness of the optimization results in practical use was ensured. Consideration was given to the high-load instantaneous condition of assisting the elderly to stand up, ensuring that the outriggers would not undergo plastic deformation or breakage. The multi-condition collaborative optimization strategy enabled the final structure to maintain optimal performance under different usage modes, meeting both the needs for easy daily movement and the high-strength support required in critical moments, achieving a perfect balance between functionality and safety.

[0021] Furthermore, through P The penalty mechanism of ≥3 strongly drives the unit density to polarize towards 0 or 1, effectively eliminating the ambiguity of intermediate density, making the optimization results clear and easy to translate into engineering applications. The model aims to minimize the overall structural flexibility, which is essentially pursuing maximum stiffness with a given amount of material, ensuring that the lightweight frame remains robust. The design cleverly avoids computational crashes caused by the singularity of the stiffness matrix, ensuring the convergence and stability of the algorithm. This makes the design results not only conform to engineering intuition but also reach the theoretical optimal solution, significantly improving the material utilization rate of the structure.

[0022] Furthermore, by correcting the sensitivity through neighborhood weighted averaging, the material distribution cloud map is smoothed, resulting in continuous and smooth structural boundaries and avoiding fragmented, unmanufacturable microporous structures. This improves the process feasibility of the optimization results and reduces the workload of subsequent geometric reconstruction. The use of the optimality criterion method for variable updates ensures efficient convergence of the iterative process, enabling the acquisition of stable optimal solutions in a short time.

[0023] Furthermore, by setting a reasonable density stripping threshold, low-stress areas are precisely eliminated while retaining key continuous outer frames and cross-stressing ribs, achieving optimal material configuration in space. The differentiated assembly design of the front and rear outriggers specifically addresses the stress characteristics of different parts. This achieves extreme lightweighting while maintaining sufficient redundancy to withstand impacts, enabling the high-end topology optimization results to be industrialized in a low-cost and high-efficiency manner.

[0024] A user-friendly mobility aid for the elderly utilizes a biomimetic skeletal truss structure to significantly reduce overall weight while maintaining extremely high structural strength, greatly alleviating the burden on elderly users. Its unique variable cross-section design distributes materials along the stress path, preventing stress concentration. A series-connected composite shock absorber dynamically compensates for damping loss due to the porous structure, isolating high-frequency hand vibrations and improving ease of use. This, combined with the series-connected composite shock absorber, effectively compensates for the reduced damping caused by the hollow structure, filtering high-frequency road vibrations and preventing vibrations from being transmitted to the elderly's arms, causing discomfort or injury. This combination of lightweight, high-strength design and active shock absorption significantly enhances the product's user-friendliness, providing a safer, more comfortable, and effortless mobility experience for elderly people with mobility issues. Furthermore, the external components are reliably coupled to the machine body via mounting brackets and connecting rods, ensuring a stable connection and efficient transmission. Internally, springs, hydraulic oil, and a bottom valve work together. The springs absorb low-frequency, large-stroke obstacle-crossing impacts, while the hydraulic oil flowing through the bottom valve orifices generates viscous damping, rapidly dissipating high-frequency, fine vibrations, resulting in excellent dual filtering. The coaxial arrangement creates a compact structure with minimal space occupation, without adding excessive weight to the machine. The compensation chamber ensures stable oil volume, and the bottom valve has high throttling accuracy, resulting in stable and reliable shock absorption. This design addresses the secondary defects of low damping and hand vibration associated with multi-hole machine bodies, significantly improving road adaptability and riding / pushing comfort, thus enhancing the user experience for elderly users.

[0025] Furthermore, the front outriggers adopt a sandwich structure with double side plates and upper and lower connecting plates, resulting in uniform load-bearing capacity and high torsional stiffness. The rear outriggers are equipped with hollow cylindrical connecting blocks to strengthen the high-stress nodes and improve overall durability. The side plates are hollowed out to retain the load-bearing frame, holes, and cross stiffeners, perfectly replicating the topology-optimized mechanical properties. All assembly structures use two-dimensional cut parts, which are simple to process, low in cost, and have a high yield rate. The standardized design of the front and rear outriggers facilitates mass production and replacement. This enables low-cost manufacturing of complex topological shapes, taking into account mechanical performance, manufacturability, and assemblability, thereby improving the equipment's cost-effectiveness and market competitiveness.

[0026] Furthermore, the three-pole linkage enables smooth switching between assisted walking and wheelchair mobility modes, ensuring no shift in the center of gravity and enhanced safety. The mechanically limited seat relies on purely mechanical dead-point load-bearing, eliminating the need for continuous motor power supply, achieving zero-energy standby and energy-efficient reliability. The modular mounting of the actuator module ensures it does not interfere with the chassis, facilitating assembly and maintenance. The posture adjustment and seat functions cater to the travel and rest needs of the elderly, enhancing the equipment's versatility and practicality. The purely mechanical limit structure provides stable load-bearing capacity and a high safety factor, avoiding safety risks caused by electrical faults and improving equipment reliability and user safety.

[0027] In summary, this invention achieves extreme lightweighting and high strength in walking aids through anti-rollover constraint topology optimization and two-dimensional assembly technology; the innovative dual-frequency composite shock absorption and multi-modal posture transformation mechanism significantly improve the walking comfort and safety reliability for elderly users; the modular design reduces manufacturing costs and has excellent engineering feasibility and market adaptability.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the following description of the relative embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart illustrating the overall process of the lightweight method for the elderly-assisting robot of the present invention. Figure 2 This is a schematic diagram of the anti-rollover force analysis and critical mass extraction mechanical model of the robot under extreme interactive conditions in an embodiment of the present invention; wherein, (a) is the user's center of gravity instability analysis state, and (b) is the stability analysis state of the elderly companion service robot; Figure 3 This is a schematic diagram of the qualitative load and boundary conditions applied to the fuselage outriggers as the initial design domain under typical working conditions in an embodiment of the present invention; wherein, (a) is the force model of the front outrigger and (b) is the force model of the rear outrigger. Figure 4 The above are verification cloud maps showing the stress deformation and equivalent stress distribution of the solid initial state fuselage legs before SIMP topology optimization in this embodiment of the invention; where (a) is the deformation cloud map and (b) is the stress cloud map. Figure 5 The above are cloud diagrams comparing the deformation and equivalent stress of the reconstructed variable cross-section porous truss structure generated by the method of this invention after removing the low stress zone; where (a) is the deformation cloud diagram and (b) is the stress cloud diagram. Figure 6 This is a schematic diagram of the physical disassembly and modular assembly structure of the variable cross-section front and rear support legs in an embodiment of the present invention; wherein, (a) is a disassembly diagram of the front support leg, and (b) is a disassembly diagram of the rear support leg; Figure 7 The following is a cross-sectional view of the internal structure of the shock absorption system and spring-hydraulic composite shock absorption device in the embodiments of the present invention; wherein, (a) is a structural diagram and (b) is a disassembled diagram of the hydraulic composite shock absorption device; Figure 8 This is an assembly drawing of a user-friendly elderly care and mobility aid device manufactured using the lightweight method described in this embodiment of the invention and equipped with a macroscopic actuator.

[0031] The components include: 1. Shock absorber; 2. Main body; 3. Body actuator; 4. Wheel assembly; 101. Front wheel mounting bracket; 102. Connecting rod; 103. Fixed seat; 104. Connecting frame; 105. Piston rod; 106. Spring; 107. Upper chamber; 108. Piston; 109. Lower chamber; 110. Bottom valve; 111. Compensation chamber; 201. Front outrigger connecting plate; 202. Front outrigger side plate; 203. Front outrigger bottom plate; 401. Hollow cylindrical connecting block; 402. Rear outrigger side plate; 403. Rear outrigger connecting plate. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0036] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0038] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0039] This invention provides a humane elderly mobility aid and its lightweight method. Based on topology optimization principles, the invention achieves lightweighting of the elderly companion robot. The main body is generated using the SIMP variable density topology optimization algorithm, and the front and rear legs are designed as variable cross-section hollow cavity structures. While meeting anti-rollover stability and mass constraints, redundant materials in low-stress areas are eliminated, achieving ultimate lightweighting of the entire machine. Furthermore, in addition to the original main body, shock absorption device, seat mechanism, and control system, the lightweight elderly companion robot is equipped with a spring-hydraulic composite shock absorption device to improve ride smoothness. A three-push-rod linkage mechanism enables smooth switching between assisted walking and wheelchair transport modes. The seat uses gear-rack transmission and mechanical limit load-bearing to ensure its humane elderly mobility aid design. This invention is the first to transform the anti-rollover safety threshold as an absolute red line into a global constraint for topology optimization, precisely eliminating redundant materials and reconstructing the porous truss using a dimensional reduction assembly method. Simultaneously, addressing the secondary defects of degraded road feel caused by the porous frame, it innovatively incorporates a fluid and mechanical composite shock absorption compensation device, perfectly balancing extreme lightweight, ease of manufacture, crash safety, and excellent ride comfort. It effectively solves the problems of short range and difficult operation caused by excessive weight in existing equipment, achieving a balance of lightweight, high rigidity, and high ride comfort.

[0040] Please see Figure 1 The present invention discloses a lightweight method for humanized elderly mobility aids, comprising the following steps: S1. Construct anti-rollover constraint boundaries The fatal flaw of existing lightweight designs lies in neglecting the deterioration of the overall anti-tipping boundary caused by weight reduction. This embodiment first performs static and dynamic modeling of the elderly companion robot under the most severe extreme interaction conditions, establishes the anti-tipping force mechanical model of the elderly companion robot, calculates the critical lower mass threshold that maintains the overall machine from tipping over under extreme interaction conditions, and transforms the critical lower mass threshold into a global volume fraction constraint condition in the topology optimization algorithm.

[0041] Please see Figure 2 The extreme interaction conditions include uphill and downhill conditions at the maximum permissible slope, as well as force conditions caused by the user's unilateral asymmetrical leaning (i.e., in the figure). Treating the entire machine and the human body as a mechanically coupled system, a torque balance equation is established between the system's center of gravity and the wheel contact point. In a critical rollover state, it is assumed that the vertical ground support force of the wheel on the unloading side (farthest from the force-bearing side) is exactly close to zero. By establishing the extreme value relationship between the stabilizing torque generated by gravity and the overturning torque generated by lateral thrust, the minimum safe mass that the entire machine must maintain is solved in reverse. Based on actual ergonomic parameters, the lower limit threshold of the anti-rollover critical safe mass for the robot of a specific size in this embodiment is 59.8 kg. Subsequently, this critical mass is irreversibly transformed into an absolute global volume fraction constraint condition in the topology optimization algorithm. This eliminates the physical hazard of overloading due to excessive weight loss at its source. The maximum volume of material that can be retained.

[0042] S2. Defining the Design Domain and Multi-Condition Loading The front and rear outriggers of the robot are defined as the initial design domain. Loads are extracted for typical operating conditions and converted into combined bending and torsion loads. The combined bending and torsion loads and displacement boundary conditions are applied to the initial design domain.

[0043] Please see Figure 3 The front and rear outriggers of the fuselage are extracted as the initial design domain. For three main operating conditions—assistance pushing / pulling, static seating, and assistance to stand up—these are transformed into combined bending and torsional qualitative loads and boundary conditions acting on the design domain. For example... Figure 3 The letters in the diagram represent: A for the bottom fixed support boundary conditions; B for the pedal lever force and armrest pressure; C for the main push rod force; D for the outrigger resistance; E for the rear cargo box mass loading; F for the load and seat mass loading; and G for the armrest reaction force. The precise application of these composite loads provides a mechanical basis for the subsequent scientific allocation of materials.

[0044] S3. Constructing a mathematical model for topology optimization A SIMP variable density topology optimization mathematical model is constructed with the objective function of minimizing the overall structural flexibility of the initial design domain, and a material interpolation function is introduced to impose a nonlinear penalty on the pseudo-density of the elements.

[0045] The specific mathematical model for SIMP variable density topology optimization is as follows: The material interpolation function is:

[0046] The objective function is:

[0047] in, For the first The elastic modulus of each unit For the first The pseudo-density of each unit and , The penalty factor has the following values: , The elastic modulus of a solid material. The minimum elastic modulus is set to avoid the singularity of the stiffness matrix in the finite element method; For the overall structural flexibility, The total displacement vector, The overall stiffness matrix, For element displacement vectors, The initial stiffness matrix of the element. The total number of units.

[0048] S4. Sensitivity Analysis and Iterative Solution Under the constraints of the global volume fraction, sensitivity analysis is performed on the objective function, and the optimality criterion method is used for variable updating and iterative solution to obtain the material pseudo density distribution cloud map of each unit in the initial design domain. In the process of sensitivity analysis and iterative solution, a grid independence filtering mechanism based on node distance is introduced. The sensitivity is corrected by calculating the weighted average of the pseudo density of the central cell and its neighboring cells, so as to suppress the checkerboard effect and grid dependence in the evolution of lightweight materials.

[0049] S5. Feature Reconstruction and Section Generation A density stripping threshold is set, and redundant material units in low-stress areas approaching 0 are removed based on the material pseudo-density distribution cloud map. The force transmission skeleton in high-stress areas approaching 1 is retained, and the front and rear legs are reconstructed into a variable cross-section porous hollow truss structure.

[0050] The density stripping threshold is set to a specific value within the range [0.2, 0.4]. Units with pseudo-density less than the density stripping threshold are regarded as redundant material units in the low-stress area and are eliminated through the entire structure. When reconstructing the variable cross-section porous truss structure, the limitation of the uniform cross-section solid structure is broken. The continuous outer force-bearing frame is retained along the principal stress transmission path. The internal low-stress area is completely hollowed out to form a through-type weight-reducing hole. At the large bending moment node, cross force transmission ribs are added between the adjacent through-type weight-reducing holes along the principal tensile and compressive stress direction. This achieves extreme weight reduction while forming a biomimetic porous skeleton shape and increasing the cross-sectional moment of inertia.

[0051] exist Under the stringent constraint of ensuring the overall machine weight is not less than 59.8 kg, the optimality criterion method (OC method) is used to perform sensitivity analysis and iteration on the objective function, and a grid independence filtering mechanism based on node distance is introduced to eliminate the "checkerboard effect". After extracting the pseudo-density distribution cloud map, the density stripping threshold is set to a specific value between [0.2, 0.4] (preferably 0.3 in this embodiment), and the pseudo-density... The elements are considered low-stress areas and are completely eliminated through them. For example... Figure 4 As shown in Figures (a) and (b), the solid leg structure before topology optimization, while absolutely safe, has a large area of ​​low-stress redundancy. Combined with... Figure 5 and Figure 6 As shown, during the engineering 3D reconstruction, the traditional manufacturing mindset of solid tubes with equal wall thickness was completely broken. The retained backbone was reconstructed into a biomimetic variable cross-section porous hollow truss structure: that is, the outer continuous stress-bearing frame is retained along the principal stress transmission path; the internal low-stress area is completely hollowed out to form multiple through-type weight-reducing holes; and at the large bending moment node, cross force transmission ribs are added between adjacent holes along the principal tensile / compressive stress direction.

[0052] Finite element mechanical property verification: Figure 5 The finite element verification data in Figure (a) Deformation cloud diagram and Figure (b) Stress cloud diagram in the figure show that, under the premise of extreme weight reduction, the maximum equivalent stress of the reconstructed porous truss is only about 41.9 MPa, which is far below the yield safety limit of light alloy materials, and the maximum deformation is controlled at a very small 0.99 mm. This achieves the unexpected technical effect of increasing stiffness and strength without decreasing them.

[0053] Engineering Manufacturability Reduction Assembly Design: To overcome the engineering manufacturing barriers of complex three-dimensional porous structures that are difficult to integrally mold and cast or machine, this embodiment innovatively proposes a low-cost fuselage configuration combining "two-dimensional plate topological cutting and three-dimensional lateral assembly." For example... Figure 6 As shown in the disassembly diagram, the resulting complex porous morphology is decomposed into a smaller, more manageable form. For the front outrigger (… Figure 6 (a) Two parallel and opposite front support leg side plates 202 are used as the main load-bearing components. The front support leg side plates 202 can be formed in one piece by two-dimensional laser cutting or CNC stamping, and the continuous outer force-bearing frame, through-type weight-reduction holes and cross force-transmitting ribs are accurately preserved in the plane. The two front support leg side plates 202 are horizontally connected and welded together by the top front support leg connecting plate 201 and the bottom front support leg base plate 203.

[0054] The rear support leg is assembled by clamping two rear support leg side plates 402 with the same porous features. At the high-stress hinge joint, a large-diameter hollow cylindrical connecting block 401 is used for lateral torsional support, and the bottom end is sealed by a rear support leg connecting plate 403. This "sandwich" assembly process perfectly and cost-effectively reproduces the box-shaped porous mechanical skeleton generated by the topology algorithm, greatly enhancing its industrialization and promotion value.

[0055] While the high-rigidity porous frame used in the aforementioned embodiments perfectly resolved the conflict between weight reduction and rollover prevention in the dynamic compensation damping system with its porous high-rigidity frame configuration, the inherent structural damping of the entire system drops drastically as a large amount of solid material is removed and replaced with a porous frame. When pushing the vehicle across rough surfaces such as tactile paving or brick joints, high-frequency resonance is easily induced, and minor bumps are transmitted to the human body without attenuation along the high-rigidity frame, resulting in severe secondary defects such as high-frequency hand vibration.

[0056] Please see Figure 7 To address this new pain point caused by lightweight algorithms, this invention independently connects a dedicated shock-absorbing device 1 between the topology-optimized fuselage body 2 and the bottom wheel assembly 4. The shock-absorbing device 1 is a spring-hydraulic composite shock absorber. Externally, it is coupled to the outrigger suspension via a front wheel mounting bracket 101, connecting rod 102, fixed seat 103, and connecting frame 104. Internally, it coaxially arranges a piston rod 105, a spring 106 as a mechanical reset element, an upper chamber 107, a piston 108, a lower chamber 109, and a high-precision bottom valve 110 and a compensation chamber 111 at the bottom.

[0057] The dynamic compensation mechanism is as follows: When a low-frequency large impact is generated when the threshold is crossed, the spring 106 quickly undergoes a large-stroke compression to absorb the main impact kinetic energy. When pushed on a rough road surface that generates high-frequency fine vibrations, the spring cannot respond in time due to static friction. At this time, the piston 108 moves slightly with the front wheel at high frequency, forcing the sealing hydraulic oil to flow quickly and forcefully through the tiny orifice of the bottom valve 110 between the upper and lower chambers 107 and 109.

[0058] Utilizing the extremely high viscosity and friction properties of liquids, the kinetic energy of high-frequency mechanical vibration is converted into fluid heat energy dissipation with remarkable sensitivity, dynamically compensating for the loss of inherent structural damping in the porous metal skeleton and completely isolating the pain point of hand vibration.

[0059] Please see Figure 8 The present invention ultimately produces a user-friendly elderly mobility aid that combines lightness, safety and high comfort. Based on a minimalist high-rigidity chassis consisting of a shock-absorbing device 1, a main body 2 manufactured using an assembly process and a wheel set 4 at the bottom, the device also modularly mounts a macroscopically encapsulated body actuator 3 in order to construct an interactive functional closed loop.

[0060] As a packaged, externally integrated actuator, the actuator 3 internally includes a three-push-rod linkage posture-changing mechanism for smooth modal switching, and a seat mechanism that relies on internal purely mechanical dead points for physical limiting and load-bearing, achieving zero-energy standby for the motor. Each actuator module works in close conjunction with the high-rigidity, porous chassis, with clear physical boundaries and no structural interference, ultimately creating a new generation of intelligent mobility assistance system that is lightweight, has low manufacturing costs, high anti-tipping safety, and an excellent pushing experience.

[0061] Please see Figure 2 A user-friendly elderly mobility aid includes: The fuselage body, which is the topology-optimized support leg, includes a front support leg and a rear support leg. Its physical entity is the variable cross-section porous hollow truss structure generated by reconstructing after removing redundant materials using the lightweight method. The walking wheel set is installed at the bottom of the main body of the machine; A composite damping device is connected in series between the lower end of the front outrigger and the corresponding walking wheel set; the composite damping device is used to dynamically compensate for the decrease in the inherent damping of the whole system structure caused by the variable cross-section porous truss structure, and to attenuate the high-frequency vibration of the road surface transmitted by the high-rigidity porous frame.

[0062] The composite shock absorber is a spring-hydraulic composite shock absorber, which is externally coupled to the main body of the machine body through a front wheel mounting bracket, connecting rod, fixed seat and connecting frame; internally, a piston rod, a spring for mechanical reset, an oil reservoir cylinder forming an upper chamber and a lower chamber, a piston, a bottom valve for throttling and a compensation chamber are arranged coaxially; the spring is used to absorb and attenuate the low-frequency, long-stroke impact energy when crossing obstacles; the oil reservoir cylinder is sealed with hydraulic oil, and the viscous fluid friction damping generated when the hydraulic oil is squeezed by the piston and flows through the tiny pores of the bottom valve absorbs and attenuates the high-frequency fine vibrations transmitted non-destructively by the variable cross-section porous hollow truss structure, realizing mechanical and fluid dual filtering.

[0063] The front and rear outriggers of the fuselage body both adopt a modular configuration combining two-dimensional plate cutting and three-dimensional lateral splicing. Specifically, the front outrigger consists of two parallel and opposite front outrigger side plates as the main load-bearing components, which are laterally connected and spliced ​​together by a top front outrigger connecting plate and a bottom front outrigger base plate. The rear outrigger consists of two parallel and opposite rear outrigger side plates as the main load-bearing components, which are laterally supported and torsional at high-stress hinge nodes by hollow cylindrical connecting blocks, and are laterally assembled and closed at the bottom by a rear outrigger connecting plate. The two-dimensional planes of both the front and rear outrigger side plates are hollowed out with continuous outer force-bearing frames, through-type weight-reducing holes, and cross force-transmitting ribs, which together form a box-shaped three-dimensional multi-hole truss after lateral assembly.

[0064] It also includes an actuator module mounted on the main body of the machine: the actuator module is a macro-control and execution combined package module, which includes a three-push-rod linkage posture change mechanism for smooth switching of the center of gravity between the assisted walking and wheelchair transport modes, and a mechanical limiting seat mechanism that relies on the internal mechanical dead point for physical limiting and load bearing when unfolded to the horizontal set position.

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0066] A support frame with high specific stiffness and anti-rollover characteristics includes an internal force transmission network distributed along the principal stress path and a weight-reducing cavity; it consists of front and rear outriggers. The front outrigger is held between two parallel front outrigger side plates 202, and is welded to form a box-shaped structure via a top front outrigger connecting plate 201 and a bottom front outrigger base plate 203; the side plates have continuous outer force-bearing frames, through-type weight-reducing holes, and cross-force transmission ribs. The rear outrigger is similar, but has a hollow cylindrical connecting block 401 at the hinge joint to resist torsion.

[0067] Multiple alternative structures: Alternative Option A: The frame can be manufactured using carbon fiber winding molding technology, directly forming a variable cross-section porous structure in one piece, eliminating the need for sheet metal splicing, further reducing weight but at a higher cost.

[0068] Alternative Option B: The connection between the side panels can be changed from welding to high-strength bolt connection or riveting, which facilitates disassembly and maintenance.

[0069] Alternative Option C: The shape of the through-hole weight reduction pores can be adjusted to a honeycomb shape, a triangular mesh shape, or an irregular biomimetic trabecular shape, as long as the stress distribution after topology optimization is met.

[0070] A force transmission interface component that converts user thrust or pull into forward power of the whole machine mainly consists of a main push rod installed on the upper part of the machine body. The lower end of the main push rod is rigidly connected to the front support leg of the frame or the actuator module, and the upper end is wrapped with a non-slip soft rubber sleeve, which conforms to the ergonomic grip angle.

[0071] Alternative Option A: Add an electric power steering unit, including a hub motor or a mid-mounted motor, as an auxiliary power source.

[0072] Alternative Option B: The main push rod is designed to be height adjustable, adapting to elderly people of different heights through a telescopic sleeve and locking knob.

[0073] Alternative C: The drive interface can be integrated with a force sensor to detect user intent and control the output torque of the electric power steering system.

[0074] A mechanical link connecting the drive end and the actuator end to realize motion form conversion or power distribution is manifested in the actuator module as a three-push-rod linkage posture change mechanism. It consists of three linear push rods (electric cylinders or hydraulic cylinders) and multiple connecting rods hinged together, which convert the linear extension and retraction motion of the push rods into the rotational and translational motion of the seat posture.

[0075] Alternative Solution A: Use a gear and rack transmission combined with a crank-slider mechanism to achieve the unfolding and folding of the seat.

[0076] Alternative Option B: Use a wire rope traction system, where a winch retracts and releases the rope to deform the seat. This structure is lighter but has slightly lower rigidity.

[0077] Alternative C: A purely mechanical cam-linkage mechanism, driven by the user's weight or a manual crank, requiring no electricity.

[0078] A functional terminal that directly supports the user or performs specific tasks, including a mechanically restrained seat mechanism. When the seat panel is unfolded to the horizontal position, the internal linkage mechanism reaches its mechanical dead point, supported by a rigid restraining block, and bears the user's weight. It also includes a rear storage space.

[0079] Alternative Option A: Add an inflatable airbag layer to the seat surface to further improve ride comfort.

[0080] Alternative Solution B: The execution module can be replaced with a medical infusion stand interface or an oxygen cylinder holder to suit rehabilitation hospital scenarios.

[0081] Alternative Option C: The seat can be designed as a split type, with independent left and right adjustments to accommodate users with different leg lengths.

[0082] The components that restrict the degree of freedom of movement of the mechanism, ensuring precise movement trajectory and safe locking, include the internal mechanical dead point structure in the mechanical limit seat mechanism and the guide groove in the posture adjustment mechanism. When the seat is fully extended, the pin falls into the slot, forming a rigid lock.

[0083] Alternative Solution A: Use an electromagnetic latch for electronic locking, and unlock with a single button on the control panel.

[0084] Alternative Option B: Use a ratchet and pawl mechanism for one-way limiting to prevent the seat from folding accidentally.

[0085] Alternative Option C: Add a swivel wheel locking lever to the front of the travel wheel assembly as a parking guide limit.

[0086] Electronic or mechanical systems that monitor, regulate, and provide auxiliary functions for equipment status; controllers that control the linkage of three push rods (embedded in the actuator); and hydraulic oil circuit control systems in composite damping devices (the size of the bottom valve orifice determines the damping characteristics).

[0087] Alternative Option A: Add an intelligent control unit, including a gyroscope and accelerometer, to monitor rollover risk in real time and issue an alarm.

[0088] Alternative Option B: Replace the composite damping device with a magnetorheological damper, which can adjust the damping magnitude in real time via current to adapt to different road conditions.

[0089] Alternative Option C: The auxiliary module includes a fall detection radar and a GPS positioning module, which connects to a cloud-based monitoring platform.

[0090] Example 1 Replace the spring-hydraulic composite shock absorber with an air spring shock absorber system.

[0091] A closed air spring bladder is installed between the lower end of the front outrigger and the walking wheel assembly. The compressibility of air absorbs shocks, and damping is generated through an additional throttle orifice.

[0092] Air springs have non-linear stiffness characteristics, and the greater the load, the higher the stiffness, making them more suitable for elderly people with large weight differences; moreover, the stiffness can be manually adjusted through the inflation valve, making them more adaptable.

[0093] Example 2 The welded connection was changed to a modular bolt connection + adhesive composite connection.

[0094] Threaded holes are pre-drilled between the front outrigger side plate and the connecting plate, and high-strength aviation aluminum bolts are used for fastening. Structural epoxy resin adhesive is applied to the contact surface.

[0095] Completely eliminates the heat-affected zone of welding, avoiding strength reduction caused by aluminum alloy welding; facilitates disassembly into flat packaging during transportation, reducing logistics costs; and allows for individual replacement of a side panel in case of damage, resulting in low repair costs.

[0096] Example 3 The electric drive of the three-push-rod linkage posture-changing mechanism was removed and replaced with manual mechanical folding.

[0097] The seat folds using a simple latch and gravity-locking hinge; users need to manually pull the handle to unlock and flip the seat.

[0098] Significantly reduces circuit costs and failure rates, making it suitable for users who are reluctant to use electronic devices or have limited budgets, and features a lighter structure.

[0099] Add an active balancing assist system.

[0100] Two retractable auxiliary support feet are added to the bottom of the fuselage. When the gyroscope detects that the tendency to tip over exceeds the threshold, the support feet will automatically pop out to expand the support surface.

[0101] Based on topology optimization and lightweight design, it provides dynamic active safety protection, pushing anti-rollover capabilities to the extreme.

[0102] In summary, this invention presents a user-friendly elderly mobility aid and its lightweighting method. Its unique anti-rollover constraint topology optimization method directly embeds physical safety thresholds into the design algorithm, ensuring from the source that while achieving extreme weight reduction (estimated at 30%-45%), the overall anti-rollover capability is not reduced but rather increased, solving a major industry pain point. A unique spring-hydraulic dual-frequency composite shock absorption system is designed to precisely separate and attenuate low-frequency impacts and high-frequency vibrations, effectively protecting the fragile bones and joints of the elderly—a feature unmatched by traditional rigid or simple spring structures. Through innovative 2D cutting and 3D assembly processes, the complex topology optimization results are transformed into low-cost standardized sheet metal processing, avoiding expensive 3D printing or casting processes. This enables large-scale industrial production of high-end customized structures, making it highly valuable for market promotion. The integrated posture-changing mechanism allows for seamless switching between mobility aid and wheelchair use, meeting the diverse travel and rest needs of the elderly and improving the overall utility of the product. This invention is a truly innovative piece of equipment embodying a people-centered and technology-driven approach to aging.

[0103] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for lightweighting user-friendly elderly mobility aids, characterized in that, Includes the following steps: S1. Static and dynamic modeling of the elderly companion robot under extreme interactive conditions is performed, an anti-rollover force mechanical model is established, the critical mass lower limit threshold for maintaining the whole machine from overturning under extreme interactive conditions is calculated, and the critical mass lower limit threshold is converted into a global volume fraction constraint condition in the topology optimization algorithm. S2. Define the front and rear outriggers of the robot body as the initial design domain, extract loads for typical operating conditions and convert them into combined bending and torsion loads, and apply the combined bending and torsion loads and displacement boundary conditions to the initial design domain. S3. Construct a SIMP variable density topology optimization mathematical model with the objective function of minimizing the overall structural flexibility of the initial design domain, and introduce a material interpolation function to nonlinearly penalize the pseudo density of the elements. S4. Under the constraints of the global volume fraction, perform sensitivity analysis on the objective function, and use the optimality criterion method to update variables and iteratively solve the problem to obtain the material pseudo-density distribution cloud map of each unit in the initial design domain. S5. Set a density stripping threshold, remove redundant material units in low-stress areas that are close to 0 according to the material pseudo-density distribution cloud map, retain the force transmission skeleton in high-stress areas that are close to 1, and reconstruct the front leg and rear leg into a variable cross-section porous hollow truss structure.

2. The lightweight method for user-friendly elderly care and mobility assistance equipment according to claim 1, characterized in that, In step S1, the extreme interaction conditions include uphill and downhill conditions under the maximum allowable slope and force conditions under the user's unilateral asymmetrical leaning. The entire machine and the human body are regarded as a mechanically coupled system. By establishing the torque balance equation between the system's center of gravity and the wheel contact point, under the critical rollover state, assuming that the ground vertical support force of the unloaded side wheel is just close to zero, by establishing the extreme value relationship between the stabilizing torque generated by gravity and the overturning torque generated by the lateral thrust, the minimum safe mass that the entire machine must maintain is solved in reverse. The minimum safe mass is used as the lower limit threshold of the critical mass. The critical mass lower limit threshold is irreversibly transformed into an absolute global volume fraction constraint in the topology optimization algorithm. ,in, The maximum volume of material that can be retained.

3. The lightweight method for user-friendly elderly care and mobility assistance equipment according to claim 1, characterized in that, In step S2, the three working conditions of assisted walking push-pull, static sitting, and support to stand up are transformed into combined bending and torsion qualitative loads and boundary conditions acting on the design domain. The boundary conditions include the bottom fixed support boundary conditions; the combined bending and torsion qualitative loads include the pedal lever force and armrest pressure, the main push rod force, the outrigger resistance, the trunk mass loading, the load and seat mass loading, and the armrest reaction force.

4. The method for lightweighting humanized elderly care and mobility assistance equipment according to claim 1, characterized in that, In step S3, the specific mathematical model for SIMP variable density topology optimization is as follows: The material interpolation function is: The objective function is: in, For the first The elastic modulus of each unit For the first The pseudo density of each unit As a penalty factor, The elastic modulus of a solid material. The minimum elastic modulus is set to avoid the singularity of the stiffness matrix in the finite element method; For the overall structural flexibility, The total displacement vector, The overall stiffness matrix, For element displacement vectors, The initial stiffness matrix of the element. The total number of units.

5. The lightweight method for user-friendly elderly care and mobility assistance equipment according to claim 1, characterized in that, In step S4, during the sensitivity analysis and iterative solution process, a grid independence filtering mechanism based on node distance is introduced. The sensitivity is corrected by calculating the weighted average of the pseudo density of the central cell and its neighboring cells, so as to suppress the checkerboard effect and grid dependence in the evolution of lightweight materials.

6. The method for lightweighting humanized elderly care and mobility assistance equipment according to claim 1, characterized in that, In step S5, the density stripping threshold is set to a specific value within the range [0.2, 0.4], and units with pseudo-density less than the density stripping threshold are regarded as redundant material units in the low-stress area and are eliminated in a thorough manner. When reconstructing the variable cross-section multi-hole hollow truss structure, the limitation of the uniform cross-section solid structure is broken, the continuous outer force-bearing frame is retained along the main stress transmission path, the internal low stress area is completely hollowed out to form a through-type weight-reducing hole, and at the large bending moment node, cross force transmission stiffeners are added between the adjacent through-type weight-reducing holes along the main tensile and compressive stress direction. During engineering 3D reconstruction, the generated complex porous morphology is decomposed into a configuration combining 2D plate topological cutting and 3D lateral assembly: For the front outrigger, two parallel and opposite front outrigger side plates are used as the main load-bearing components. The continuous outer force-bearing frame, through-type weight-reduction hole and cross force-transmitting rib plate are precisely preserved in the plane of the front outrigger side plate. The two front outrigger side plates are horizontally connected and welded together by the top front outrigger connecting plate and the bottom front outrigger base plate. The rear outrigger is assembled by clamping two rear outrigger side plates with the same porous features. At the high-stress hinge joint, a large-diameter hollow cylindrical connecting block is used for lateral torsional support, and the bottom end is sealed by a rear outrigger connecting plate.

7. A user-friendly elderly mobility aid, characterized in that, include: The fuselage body (2) includes a front support leg and a rear support leg, both of which are variable cross-section porous truss structures prepared by the lightweighting method described in any one of claims 1 to 6. The walking wheel assembly (4) is installed at the bottom of the main body (2); A composite shock absorber (1) is connected in series between the lower end of the front support leg and the corresponding walking wheel set (4); The variable cross-section multi-hole hollow truss structure has a continuous outer force-bearing frame, a through-type weight-reducing hole, and cross force-transmitting stiffeners set between adjacent through-type weight-reducing holes. The composite damping device (1) is used to dynamically compensate for the decrease in the inherent damping of the whole system structure caused by the variable cross-section porous hollow truss structure, and to attenuate the high-frequency vibration of the road surface transmitted by the high-rigidity porous frame.

8. The user-friendly elderly care and mobility aid equipment according to claim 7, characterized in that, The composite shock absorber (1) is a spring-hydraulic composite shock absorber, which is externally coupled to the main body (2) of the fuselage through a front wheel mounting bracket (101), a connecting rod (102), a fixed seat (103), and a connecting frame (104); The composite damping device (1) has a piston rod (105), a spring (106), an oil reservoir cylinder, a piston (108), a bottom valve (110), and a compensation chamber (111) arranged coaxially inside. The oil reservoir has an upper chamber (107) and a lower chamber (109) formed inside. The piston (108) is located inside the oil reservoir and divides the oil reservoir into the upper chamber (107) and the lower chamber (109). The piston rod (105) is connected to the piston (108), and the spring (106) is sleeved on the piston rod (105). The bottom valve (110) is located at the bottom of the oil storage cylinder, and the compensation chamber (111) is connected to the bottom valve (110); The spring (106) is used to absorb and attenuate the low-frequency, long-stroke impact energy during obstacle crossing. The oil storage cylinder is sealed with hydraulic oil. The viscous fluid friction damping generated when the hydraulic oil is squeezed by the piston (108) and flows through the tiny pores of the bottom valve (110) absorbs and attenuates the high-frequency fine vibrations transmitted non-destructively by the variable cross-section porous hollow truss structure.

9. The user-friendly elderly care and mobility assistance equipment according to claim 7, characterized in that, Both the front support leg and the rear support leg adopt a modular configuration that combines two-dimensional plate cutting with three-dimensional horizontal splicing; The front support leg consists of two parallel and opposite front support leg side plates (202) as the main load-bearing components. The two front support leg side plates (202) are laterally connected and assembled through the top front support leg connecting plate (201) and the bottom front support leg base plate (203). The rear support leg consists of two parallel and opposite rear support leg side plates (402) as the main load-bearing components. The two rear support leg side plates (402) are laterally supported and resisted torsion at the high stress hinge joint by a hollow cylindrical connecting block (401). The bottom end is laterally assembled and closed by a rear leg connecting plate (403). Both the front support leg side plate (202) and the rear support leg side plate (402) have the continuous outer force-bearing frame, the through-type weight-reducing hole and the cross force-transmitting rib plate hollowed out in the two-dimensional plane, and together they form a box-shaped three-dimensional multi-hole truss after being assembled laterally.

10. The user-friendly elderly care and mobility aid equipment according to claim 7, characterized in that, It also includes an actuator module (3) mounted on the fuselage body (2); The actuator module (3) is a macro-control and execution combined encapsulation module, which includes a three-pole linkage posture change mechanism for smooth switching of center of gravity between the assisted walking and wheelchair transport modes, and a mechanical limit seat mechanism that relies on the internal mechanical dead point for physical limit load bearing when unfolded to the horizontal set position.

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