A target seat posture acquisition method and system based on optimal fatigue degree

Abstract

The application discloses a target seat posture acquisition method and system based on optimal fatigue, and relates to the field of automobile seat adjustment. A human body skeletal muscle model is constructed according to human body size data, a human-chair coupling simulation model is constructed by using the human body skeletal muscle model and a seat model for kinematic constraint based on biomechanical simulation software, variable values corresponding to the seat posture are initialized and written into an intermediate file, the intermediate file is read by the biomechanical simulation software, the seat posture is adjusted based on the variable values in the intermediate file, the lumbar force, muscle force and human-chair contact force corresponding to the current driver are calculated based on the adjusted seat posture to obtain a comprehensive fatigue, the variable values in the intermediate file are updated, and the seat posture is adjusted based on the updated variable values until the minimum comprehensive fatigue is obtained, the simulation of a driving scene is realized, the fatigue evaluation index is enriched, and the calculation accuracy of the comprehensive fatigue is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive seat adjustment, and more particularly to a method and system for obtaining a target seat posture based on optimal fatigue level. Background Technology

[0002] Current seat designs need to balance safety, comfort, and ease of assembly. Seat comfort design typically considers parameters such as comfort cross-sections and the distance between the passenger and the frame's hard points. Passengers usually adjust the seat to their preferred position after boarding, or use the memory function, but it's impossible to determine if this position is optimal, nor can optimal comfort be determined from a biological perspective. Current biomechanical fatigue assessment models are relatively simple, generally focusing on joint and muscle forces, with limited evaluation indicators, especially in non-driving environments. In driving scenarios, however, there is extensive contact between the passenger and the driver's cab, and driving fatigue is caused by multiple factors. Therefore, current fatigue assessment models lack accuracy. To address these technical problems, this invention proposes a method and system for obtaining the target seat posture based on optimal fatigue, utilizing multi-dimensional information. Summary of the Invention

[0003] To address the problem that current fatigue assessment models rely on a single evaluation index and fail to consider the contact characteristics between the driver and the cab, resulting in insufficient accuracy, this invention proposes a method for obtaining the target seat posture based on optimal fatigue level, comprising: S1: Obtain the current driver's body size data, construct a human skeletal and muscular model based on the body size data, and use biomechanical simulation software to apply kinematic constraints between the human skeletal and muscular model and the seat model to construct a human-chair coupled simulation model. S2: Initialize the variable values ​​corresponding to the seat posture and write them to the intermediate file. Set the seat posture as the optimization variable and set the minimum overall fatigue as the optimization target. S3: Read the intermediate file through biomechanical simulation software and load it into the human-chair coupled simulation model, and adjust the seat posture based on the intermediate file; S4: Based on the adjusted seat posture, the lumbar force, muscle force and human-seat contact force of the current driver are calculated using biomechanical simulation software with kinematic constraints and dynamic conditions. S5: Calculate the overall fatigue level using the lumbar spine force, muscle force, and human-seat contact force corresponding to the current driver and store it in the data table. Update the variable values ​​in the intermediate file through a preset algorithm and return to step S3 until the minimum overall fatigue level is obtained. Set the seat posture corresponding to the minimum overall fatigue level as the target seat posture corresponding to the current driver.

[0004] Furthermore, the preset algorithm is gradient descent, genetic algorithm, or enumeration.

[0005] Furthermore, the lumbar force includes the anterior-posterior and lateral components of the force corresponding to the L4-L5 segments of the lumbar spine; the muscle force includes the activation degree of each subdivided muscle in the shoulder muscle group, spinal muscle group, thigh muscle group, and calf muscle group; the human-chair contact force includes the normal force and shear force on the seat cushion and the normal force and shear force on the backrest.

[0006] Furthermore, the kinematic constraints include H-point constraints, back intrusion point constraints, constraints between the foot and the pedal, and constraints between the hand and the steering wheel.

[0007] Furthermore, in step S5, the formula for calculating the overall fatigue level is: ; in: ; ; ; In the formula, Indicates an index for evaluating muscle activation. This indicates the human-chair contact force evaluation index. Indicates the lumbar spine force evaluation index, They represent , , The corresponding weights Indicates overall fatigue level. This is an array containing the activation levels of each sub-muscle within the shoulder muscle group. This is an array containing the activation levels of each sub-muscle within the spinal muscle group. This is an array containing the activation levels of each sub-muscle within the thigh muscle group. This is an array containing the activation values ​​of each sub-muscle in the calf muscle group. This indicates the maximum activation level in the current muscle group. This indicates the average activation level of the current muscle group. This represents the weight corresponding to the maximum activation level. This represents the weight corresponding to the average activation level; and These represent the normal force and shear force on the seat cushion, respectively. and These represent the normal force and shear force on the backrest, respectively. and These represent the maximum normal force and the average normal force on the seat cushion, respectively. and These represent the maximum shear force and the average shear force on the seat cushion, respectively. and These represent the maximum normal force and the average normal force on the backrest, respectively. and These represent the maximum shear force and the average shear force on the backrest, respectively. These represent the weights corresponding to the maximum contact force and the average contact force, respectively. These represent the anterior-posterior force and lateral-lateral force corresponding to the L4-L5 segments of the lumbar spine, respectively.

[0008] Furthermore, the variable values ​​corresponding to the seat posture include: the fore-and-aft adjustment of the seat cushion, the height adjustment of the seat cushion, and the angle between the backrest and the seat cushion.

[0009] Furthermore, the human body size data includes: height and weight.

[0010] This invention also proposes a target seat posture acquisition system based on optimal fatigue, comprising: The model building module is used to acquire the current driver's body size data, build a human skeletal and muscular model based on the body size data, and use biomechanical simulation software to apply kinematic constraints between the human skeletal and muscular model and the seat model to build a human-chair coupled simulation model. The initialization module is used to initialize the variable values ​​corresponding to the seat posture and write them to the intermediate file. The seat posture is set as the optimization variable, and the minimum overall fatigue is set as the optimization target. The adjustment module is used to read intermediate files through biomechanical simulation software and load them into the human-chair coupled simulation model, and adjust the seat posture based on the intermediate files; The calculation module is used to calculate the lumbar force, muscle force and human-seat contact force of the current driver based on the adjusted seat posture using biomechanical simulation software with kinematic constraints and dynamic conditions. The optimization module is used to calculate the overall fatigue level using the lumbar spine force, muscle force, and human-seat contact force of the current driver and store it in a data table. It updates the variable values ​​in the intermediate file through a preset algorithm and repeatedly adjusts the human-seat coupling simulation model through the adjustment module until the minimum overall fatigue level is obtained. The seat posture corresponding to the minimum overall fatigue level is set as the target seat posture of the current driver.

[0011] Furthermore, the preset algorithm is gradient descent, genetic algorithm, or enumeration; the lumbar force includes the anterior-posterior and lateral components of the force corresponding to the L4-L5 segments of the lumbar spine; the muscle force includes the activation degree of each subdivided muscle in the shoulder muscle group, spinal muscle group, thigh muscle group, and calf muscle group; the human-chair contact force includes the normal and shear forces on the seat cushion and the normal and shear forces on the backrest; the kinematic constraints include H-point constraints, back intrusion point constraints, constraints between the feet and pedals, and constraints between the hands and the steering wheel.

[0012] Furthermore, the variable values ​​corresponding to the seat posture include: the fore-and-aft adjustment of the seat cushion, the height adjustment, and the angle between the backrest and the seat cushion; the human body size data includes: height and weight.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects: This invention constructs a human skeletal and muscular model based on human body size data. Using biomechanical simulation software, it applies kinematic constraints between the human skeletal and muscular model and a seat model to construct a human-chair coupled simulation model. The invention initializes the variable values ​​corresponding to the seat posture and writes them into an intermediate file. The biomechanical simulation software reads the intermediate file and adjusts the seat posture based on the variable values. Based on the adjusted seat posture, it calculates the lumbar spine force, muscle force, and human-chair contact force corresponding to the current driver to obtain the comprehensive fatigue level. The variable values ​​in the intermediate file are then updated, and the seat posture is adjusted again based on the updated variable values ​​until the minimum comprehensive fatigue level is obtained. This invention simulates different driving scenarios by updating the variable values ​​corresponding to the seat posture. Furthermore, it improves the accuracy and reliability of the comprehensive fatigue level calculation by calculating the lumbar spine force, muscle force, and human-chair contact force corresponding to the current driver. By using lumbar spine force, muscle force, and human-chair contact force as the calculation data for comprehensive fatigue level, this invention enriches the fatigue evaluation indicators and further improves the accuracy of comprehensive fatigue level calculation. Attached Figure Description

[0014] Figure 1 A flowchart of a method for obtaining the target seat posture based on optimal fatigue. Figure 2 A block diagram of a target seat posture acquisition system based on optimal fatigue. Figure 3 The diagram shows the human-chair coupling simulation model. Detailed Implementation

[0015] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0016] Example 1 To address the problem that current fatigue assessment models rely on a single evaluation index and fail to consider the contact characteristics between the driver and the cab, resulting in insufficient accuracy, such as... Figure 1 As shown, this invention proposes a method for obtaining the target seat posture based on optimal fatigue, including: S1: Obtain the current driver's body dimensions data, construct a human skeletal and muscular model based on the body dimensions data, and apply kinematic constraints between the human skeletal and muscular model and the seat model (specifically, a 3D seat model) using biomechanical simulation software to construct a model as follows: Figure 3 The human-chair coupling simulation model shown; the human body size data includes: height and weight.

[0017] In this embodiment, the biomechanical simulation software is Anybody, Opensim, or Mujoco, etc. Specifically, the human skeletal muscle model and the three-dimensional model of the chair are imported into the biomechanical simulation software to construct a human-chair coupled simulation model.

[0018] S2: Initialize the variable values ​​corresponding to the seat posture and write them to the intermediate file. Set the seat posture as the optimization variable and set the minimum overall fatigue as the optimization target. The variable values ​​corresponding to the seat posture include: the seat cushion fore-aft adjustment amount, the height adjustment amount, and the angle between the backrest and the seat cushion.

[0019] S3: Read the intermediate file through biomechanical simulation software and load it into the human-chair coupled simulation model, and adjust the seat posture based on the intermediate file; The kinematic constraints include H-point constraints, back intrusion point constraints, constraints between the foot and the pedals, and constraints between the hand and the steering wheel.

[0020] S4: Based on the adjusted seat posture, the lumbar force, muscle force and human-seat contact force of the current driver are calculated using biomechanical simulation software with kinematic constraints and dynamic conditions. It should be noted that the dynamic conditions are used to set the muscle forces and external forces in the human-chair coupling simulation model, that is, to achieve the set human posture through the combined action of muscle forces and external forces. Among them, the external forces include the supporting forces of the seat, footrests, and steering wheel on the human skeletal muscle model.

[0021] The lumbar force includes the anterior-posterior and lateral components of the force corresponding to the L4-L5 segments of the lumbar spine; the muscle force includes the activation degree of each subdivided muscle in the shoulder muscle group, spinal muscle group, thigh muscle group, and calf muscle group; the human-chair contact force includes the normal force and shear force on the seat cushion and the normal force and shear force on the backrest.

[0022] S5: Calculate the overall fatigue level using the lumbar spine force, muscle force, and human-seat contact force corresponding to the current driver and store it in the data table. Update the variable values ​​in the intermediate file and return to step S3 until the minimum overall fatigue level is obtained. Set the seat posture corresponding to the minimum overall fatigue level as the target seat posture corresponding to the current driver.

[0023] The formula model for calculating overall fatigue consists of three sub-indicators, used to evaluate muscle activation, human-chair contact force, and lumbar spine force, respectively. The expression of the formula model is as follows: ; In this embodiment, weight , , It can be adjusted according to actual application needs; those with experience can select... ; in: In the formula, 0.045 represents the commonly used muscle activation level, used for dimensionless calculation; in this embodiment, The lower the muscle activation level, the lower the likelihood of muscle fatigue. F The smaller, the more comfortable; In the formula, 600 is a commonly used value used for dimensionless transformation; in this embodiment, The more uniform the contact force distribution, the lower the maximum contact force, and the lower the likelihood of fatigue. H The smaller, the more comfortable; The L4-L5 segment of the lumbar spine is prone to soreness and fatigue when sitting in an incorrect posture. Therefore, the force between the L4-L5 segments of the lumbar spine is used to describe the fatigue of the lower back. For the overall index G, the lower the force, the lower the possibility of fatigue, that is, the smaller the G, the higher the comfort. Each of the above sub-indicators has a specific calculation weight, and the weight of each indicator can be adjusted according to different actual application scenarios; In the formula, Indicates an index for evaluating muscle activation. This indicates the human-chair contact force evaluation index. Indicates the lumbar spine force evaluation index, They represent , , The corresponding weights Indicates overall fatigue level. This is an array containing the activation levels of each sub-muscle within the shoulder muscle group. This is an array containing the activation levels of each sub-muscle within the spinal muscle group. This is an array containing the activation levels of each sub-muscle within the thigh muscle group. This is an array containing the activation values ​​of each sub-muscle in the calf muscle group. This indicates the maximum activation level in the current muscle group. This indicates the average activation level of the current muscle group. This represents the weight corresponding to the maximum activation level. This represents the weight corresponding to the average activation level; and These represent the normal force and shear force on the seat cushion, respectively. and These represent the normal force and shear force on the backrest, respectively. and These represent the maximum normal force and the average normal force on the seat cushion, respectively. and These represent the maximum shear force and the average shear force on the seat cushion, respectively. and These represent the maximum normal force and the average normal force on the backrest, respectively. and These represent the maximum shear force and the average shear force on the backrest, respectively. These represent the weights corresponding to the maximum contact force and the average contact force, respectively. These represent the anterior-posterior force and lateral-lateral force corresponding to the L4-L5 segments of the lumbar spine, respectively.

[0024] It should be noted that the activation level of each sub-muscle is directly provided by the biomechanical simulation software.

[0025] In step S5, the variable values ​​in the intermediate file are updated using gradient descent, genetic algorithm, or enumeration. If enumeration is used, the seat posture (variable value) is updated linearly. When using enumeration to update the variable values ​​in the intermediate file, the minimum value is selected by comparing the overall fatigue level under each seat posture (or under each update), and the seat posture corresponding to the minimum overall fatigue level is set as the target seat posture for the current driver.

[0026] This invention can perform simulation calculations on human body models of different body types to obtain the target seat posture (optimal seat posture) corresponding to users with different body characteristics.

[0027] This invention constructs a human skeletal and muscular model based on human body size data. Using biomechanical simulation software, it applies kinematic constraints between the human skeletal and muscular model and a seat model to construct a human-chair coupled simulation model. The invention initializes the variable values ​​corresponding to the seat posture and writes them into an intermediate file. The biomechanical simulation software reads the intermediate file and adjusts the seat posture based on the variable values. Based on the adjusted seat posture, it calculates the lumbar spine force, muscle force, and human-chair contact force corresponding to the current driver to obtain the comprehensive fatigue level. The variable values ​​in the intermediate file are then updated, and the seat posture is adjusted again based on the updated variable values ​​until the minimum comprehensive fatigue level is obtained. This invention simulates different driving scenarios by updating the variable values ​​corresponding to the seat posture. Furthermore, it improves the accuracy and reliability of the comprehensive fatigue level calculation by calculating the lumbar spine force, muscle force, and human-chair contact force corresponding to the current driver. By using lumbar spine force, muscle force, and human-chair contact force as the calculation data for comprehensive fatigue level, this invention enriches the fatigue evaluation indicators and further improves the accuracy of comprehensive fatigue level calculation.

[0028] Example 2 like Figure 2 As shown, this invention also proposes a target seat posture acquisition system based on optimal fatigue, comprising: The model building module is used to acquire the current driver's body size data, build a human skeletal and muscular model based on the body size data, and use biomechanical simulation software to apply kinematic constraints between the human skeletal and muscular model and the seat model to build a human-chair coupled simulation model. The initialization module is used to initialize the variable values ​​corresponding to the seat posture and write them to the intermediate file. The seat posture is set as the optimization variable, and the minimum overall fatigue is set as the optimization target. The adjustment module is used to read intermediate files through biomechanical simulation software and load them into the human-chair coupled simulation model, and adjust the seat posture based on the intermediate files; The calculation module is used to calculate the lumbar force, muscle force and human-seat contact force of the current driver based on the adjusted seat posture using biomechanical simulation software with kinematic constraints and dynamic conditions. The optimization module is used to calculate the overall fatigue level using the lumbar spine force, muscle force, and human-seat contact force of the current driver and store it in a data table. It updates the variable values ​​in the intermediate file through a preset algorithm and repeatedly adjusts the human-seat coupling simulation model through the adjustment module until the minimum overall fatigue level is obtained. The seat posture corresponding to the minimum overall fatigue level is set as the target seat posture of the current driver.

[0029] The preset algorithm is gradient descent, genetic algorithm, or enumeration; the lumbar force includes the anterior-posterior and lateral components of the force corresponding to the L4-L5 segments of the lumbar spine; the muscle force includes the activation degree of each subdivided muscle in the shoulder muscle group, spinal muscle group, thigh muscle group, and calf muscle group; the human-chair contact force includes the normal and shear forces on the seat cushion and the normal and shear forces on the backrest; the kinematic constraints include H-point constraints, back intrusion point constraints, constraints between the feet and pedals, and constraints between the hands and the steering wheel.

[0030] The variable values ​​corresponding to the seat posture include: the seat cushion fore-and-aft adjustment amount, the height adjustment amount, and the angle between the backrest and the seat cushion; the human body size data includes: height and weight.

[0031] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0032] Furthermore, in this invention, descriptions involving terms such as "first," "second," and "a" are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. A method for obtaining the posture of a target seat based on optimal fatigue, characterized in that, include: S1: Obtain the current driver's body size data, construct a human skeletal and muscular model based on the body size data, and use biomechanical simulation software to perform kinematic constraints on the human skeletal and muscular model and the seat model to construct a human-chair coupled simulation model. S2: Initialize the variable values ​​corresponding to the seat posture and write them to the intermediate file. Set the seat posture as the optimization variable and set the minimum overall fatigue as the optimization target. S3: Read the intermediate file through biomechanical simulation software and load it into the human-chair coupled simulation model, and adjust the seat posture based on the intermediate file; S4: Based on the adjusted seat posture, the lumbar force, muscle force and human-seat contact force of the current driver are calculated using biomechanical simulation software with kinematic constraints and dynamic conditions. The lumbar force includes the anterior-posterior and lateral components of the force corresponding to the L4-L5 segments of the lumbar spine; the muscle force includes the activation degree of each sub-muscle in the shoulder muscle group, spinal muscle group, thigh muscle group, and calf muscle group. The contact force between the person and the chair includes the normal force and shear force on the seat cushion and the normal force and shear force on the backrest; S5: Calculate the overall fatigue level using the lumbar spine force, muscle force and human-seat contact force corresponding to the current driver and store it in the data table. Update the variable values ​​in the intermediate file and return to step S3 until the minimum overall fatigue level is obtained. Set the seat posture corresponding to the minimum overall fatigue level as the target seat posture corresponding to the current driver. In step S5, the formula for calculating the overall fatigue level is: ； ； ； ； In the formula, Indicates an index for evaluating muscle activation. This indicates the human-chair contact force evaluation index. Indicates the lumbar spine force evaluation index, They represent , , The corresponding weights Indicates overall fatigue level. This is an array containing the activation levels of each sub-muscle within the shoulder muscle group. This is an array containing the activation levels of each sub-muscle within the spinal muscle group. This is an array containing the activation levels of each sub-muscle within the thigh muscle group. This is an array containing the activation values ​​of each sub-muscle in the calf muscle group. This indicates the maximum activation level in the current muscle group. This indicates the average activation level of the current muscle group. This represents the weight corresponding to the maximum activation level. This represents the weight corresponding to the average activation level; and These represent the normal force and shear force on the seat cushion, respectively. and These represent the normal force and shear force on the backrest, respectively. and These represent the maximum normal force and the average normal force on the seat cushion, respectively. and These represent the maximum shear force and the average shear force on the seat cushion, respectively. and These represent the maximum normal force and the average normal force on the backrest, respectively. and These represent the maximum shear force and the average shear force on the backrest, respectively. These represent the weights corresponding to the maximum contact force and the average contact force, respectively. These represent the anterior-posterior force and lateral-lateral force corresponding to the L4-L5 segments of the lumbar spine, respectively.

2. The method for obtaining the target seat posture based on optimal fatigue degree according to claim 1, characterized in that, In step S5, the variable values ​​in the intermediate file are updated using gradient descent, genetic algorithm, or enumeration.

3. The method for obtaining the target seat posture based on optimal fatigue degree according to claim 2, characterized in that, The kinematic constraints include H-point constraints, back intrusion point constraints, constraints between the foot and the pedals, and constraints between the hand and the steering wheel.

4. A method for obtaining the target seat posture based on optimal fatigue degree according to any one of claims 1 to 3, characterized in that, The variable values ​​corresponding to the seat posture include: the seat cushion fore-aft adjustment amount, the height adjustment amount, and the angle between the backrest and the seat cushion.

5. The method for obtaining the target seat posture based on optimal fatigue degree according to claim 1, characterized in that, The human body size data includes: height and weight.

6. A target seat posture acquisition system based on optimal fatigue, characterized in that, include: The model building module is used to acquire the current driver's body size data, build a human skeletal and muscular model based on the body size data, and use biomechanical simulation software to apply kinematic constraints between the human skeletal and muscular model and the seat model to build a human-chair coupled simulation model. The initialization module is used to initialize the variable values ​​corresponding to the seat posture and write them to the intermediate file. The seat posture is set as the optimization variable, and the minimum overall fatigue is set as the optimization target. The adjustment module is used to read intermediate files through biomechanical simulation software and load them into the human-chair coupled simulation model, and adjust the seat posture based on the intermediate files; The calculation module is used to calculate the lumbar force, muscle force and human-seat contact force of the current driver based on the adjusted seat posture using biomechanical simulation software with kinematic constraints and dynamic conditions. The lumbar force includes the anterior-posterior and lateral components of the force corresponding to the L4-L5 segments of the lumbar spine; the muscle force includes the activation degree of each sub-muscle in the shoulder muscle group, spinal muscle group, thigh muscle group, and calf muscle group. The contact force between the person and the chair includes the normal force and shear force on the seat cushion and the normal force and shear force on the backrest; The optimization module is used to calculate the overall fatigue level using the lumbar spine force, muscle force and human-seat contact force of the current driver and store it in the data table. It updates the variable values ​​in the intermediate file through a preset algorithm and repeatedly adjusts the human-seat coupling simulation model through the adjustment module until the minimum overall fatigue level is obtained. The seat posture corresponding to the minimum overall fatigue level is set as the target seat posture of the current driver. The formula for calculating overall fatigue level is: ； ； ； ； In the formula, Indicates an index for evaluating muscle activation. This indicates the human-chair contact force evaluation index. Indicates the lumbar spine force evaluation index, They represent , , The corresponding weights Indicates overall fatigue level. This is an array containing the activation levels of each sub-muscle within the shoulder muscle group. This is an array containing the activation levels of each sub-muscle within the spinal muscle group. This is an array containing the activation levels of each sub-muscle within the thigh muscle group. This is an array containing the activation values ​​of each sub-muscle in the calf muscle group. This indicates the maximum activation level in the current muscle group. This indicates the average activation level of the current muscle group. This represents the weight corresponding to the maximum activation level. This represents the weight corresponding to the average activation level; and These represent the normal force and shear force on the seat cushion, respectively. and These represent the normal force and shear force on the backrest, respectively. and These represent the maximum normal force and the average normal force on the seat cushion, respectively. and These represent the maximum shear force and the average shear force on the seat cushion, respectively. and These represent the maximum normal force and the average normal force on the backrest, respectively. and These represent the maximum shear force and the average shear force on the backrest, respectively. These represent the weights corresponding to the maximum contact force and the average contact force, respectively. These represent the anterior-posterior force and lateral-lateral force corresponding to the L4-L5 segments of the lumbar spine, respectively.

7. The target seat posture acquisition system based on optimal fatigue degree according to claim 6, characterized in that, The preset algorithm is gradient descent, genetic algorithm or enumeration; the kinematic constraints include H-point constraint, back intrusion point constraint, constraint between foot and pedal and constraint between hand and steering wheel.

8. The target seat posture acquisition system based on optimal fatigue degree according to claim 7, characterized in that, The variable values ​​corresponding to the seat posture include: the seat cushion fore-and-aft adjustment amount, the height adjustment amount, and the angle between the backrest and the seat cushion; the human body size data includes: height and weight.

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