A method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution

Abstract

The present invention is applicable to the technical field of automobile seat design and provides a method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution, comprising the following steps: conducting an experiment and recording static body pressure distribution data, measuring the positional relationship between the body pressure distribution area and the seat back rotation axis; respectively calculating the torque generated at the backrest rotation axis when the human body weight component acts on the backrest and the torque generated at the backrest rotation axis by the weight of the seat backrest, and adding the two calculated torques to obtain the total torque at the backrest angle adjustment hinge. The present invention can directly install a body pressure sensor for experiments on different seats, simplifying the experimental steps, reducing experimental costs, and saving time. At the same time, the method is universal for calculating the torque of different working conditions and different seats, and can quickly and accurately obtain the output torque range of the backrest angle adjustment motor during normal operation, thereby avoiding waste when selecting the motor, making reasonable selection, and effectively reducing the cost of the motor.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile seat design, and in particular relates to a method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution. Background Art

[0002] Amidst the booming modern automotive industry and continuous technological advancements, consumers' expectations for vehicle comfort are rising. As a key component that directly interacts with vehicle occupants, the comfort of car seats has become a crucial factor influencing the user experience. To meet this demand, an increasing number of vehicle models are adopting electrically controlled seat adjustment. Power seats in mid- to high-end vehicles are commonly equipped with motors for multiple position and angle adjustments, including fore / aft adjustment, up / down adjustment, backrest adjustment, and headrest adjustment. Therefore, motor design and selection have become crucial aspects of seat design. For the backrest angle adjustment motor, selecting the optimal torque is particularly crucial: the torque must ensure sufficient power to drive seat adjustment and maintain proper operation under heavy loads, while also avoiding the cost and energy waste caused by excessive torque. Therefore, quickly and accurately determining the output torque range of the backrest angle adjustment motor for normal operation has become a pressing challenge in seat design.

[0003] Traditional motor design methods typically obtain data from physical prototype test results to determine the torque experienced by the seat back hinge under normal driving conditions and to calculate the hinge motor output torque for motor selection. This process is not only cumbersome but also costly, requiring significant time and manpower. Furthermore, this method lacks versatility for torque measurement across different seats, making it difficult to meet diverse seat design requirements. To address this issue, the present invention proposes a method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution. Summary of the Invention

[0004] The object of the present invention is to provide a method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution, aiming to solve the problems raised in the above background technology.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution comprises the following steps:

[0007] Step S1: test data recording and measurement;

[0008] Conduct tests and record static body pressure distribution data, measuring the positional relationship between the body pressure distribution area and the seat back rotation axis;

[0009] Step S2: Calculate the torque generated by the weight of the human body at the backrest rotation axis;

[0010] Based on the static body pressure distribution data, the pressure on the sensing area of ​​each part of the backrest and the length of the force arm relative to the backrest rotation axis are calculated respectively, and the torque generated at the backrest rotation axis when the human body weight acts on the backrest is calculated;

[0011] Step S3: Calculate the torque generated by the weight of the seat back at the backrest rotation axis;

[0012] Estimate the mass and center of gravity of the backrest using computer-aided design software, measure the length of the gravity arm, and calculate the torque generated by the weight of the seat back at the backrest rotation axis;

[0013] Step S4: Calculate the total torque at the backrest shaft;

[0014] The torques calculated in step S2 and step S3 are added together to obtain the total torque at the backrest angle adjustment hinge.

[0015] Furthermore, the specific process of step S1 is as follows:

[0016] Fix the test seat on a test bench that simulates the vehicle vehicle environment, adjust the installation position and ensure that the body pressure sensor covers the entire seat back. After the test subject sits down, maintain a driving or sitting posture, collect body pressure sensor data from the backrest, and select a stable frame of data from the obtained static body pressure distribution data for recording. Open the test seat model data in computer-aided design software, calibrate the position of the backrest shaft axis and the position of the body pressure sensor sensing area, and measure the force arm length d1 from the lower edge of the sensing area to the axis of the backrest shaft.

[0017] Furthermore, the specific process of step S2 is as follows:

[0018] The static body pressure distribution data of the backrest is divided into m rows and n columns, with a total of m*n measurement areas. Each area has a side length of a square; record the central pressure of each independent sensing area Data, where i=1,2...m; j=1,2...n; calculate the pressure of each sensing area according to the following formula :

[0019] ;

[0020] The pressure of the sensing area in the jth column is added together to obtain the pressure of the jth column area and F j :

[0021] ;

[0022] The distance between the center point of the j-th column area and the lower edge of the sensing area for:

[0023] ;

[0024] Then the length of the force arm of the pressure in the jth column area to the axis of the backrest shaft is for:

[0025] ;

[0026] It is stipulated that the positive direction is the direction pointing to the right side of the seat along the axis of the backrest shaft, then the torque of the pressure in the jth column area on the axis of the backrest shaft is for:

[0027] ;

[0028] Add up the torques in the n-column area to get the torque M1 of the backrest area body pressure on the backrest shaft center:

[0029] ;

[0030] M1 is the torque generated at the backrest shaft when the weight of the human body acts on the backrest under driving conditions.

[0031] Furthermore, the specific process of step S3 is as follows:

[0032] Open the test seat model data in CATIA software. When estimating the mass of the backrest, only the mass of the metal frame is estimated. The mass coefficient of the headrest, sponge, and vibration damping device components is selected. To calculate; select the seat back frame structure, select the material corresponding to the seat frame in the material properties, measure the inertia of the frame structure, and obtain the center of gravity coordinates of the frame structure (G x , G y , G z ), with mass m1; in the model, the coordinates (G x , G y , G z ) Determine the center of gravity of the backrest frame, draw a perpendicular line through the center of gravity to the horizontal plane, and measure the distance L2 between the perpendicular line and the axis of the backrest rotation axis; estimate the total mass m of the test seat backrest as:

[0033] ;

[0034] Select the gravity acceleration constant g = 9.8N / kg and calculate the backrest gravity G as:

[0035] ;

[0036] Calculate the torque M2 of the seat back's gravity on the backrest's rotation axis:

[0037] ;

[0038] It is the torque generated by the weight of the seat back at the backrest rotation axis under driving conditions.

[0039] Furthermore, the specific process of step S4 is as follows:

[0040] The total torque M at the seat backrest shaft is obtained by adding the torque generated at the seat backrest shaft by the weight of the human body acting on the seat backrest and the torque generated at the seat backrest shaft by the weight of the seat backrest:

[0041] ;

[0042] Based on the total torque M, determine the output torque range of the backrest angle adjustment motor during normal operation and select the motor.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention provides an engineering method for selecting a hinge motor by simply measuring the static body pressure distribution data of the seat during driving and combining it with the three-dimensional model data of the seat structure to calculate the torque at the seat back angle adjustment hinge. This method allows for direct installation of body pressure sensors for experiments on different seats, simplifying the experimental steps, reducing experimental costs, and saving time. Furthermore, the method is universal for calculating torque under different working conditions and for different seats, and can quickly and accurately determine the output torque range of the back angle adjustment motor during normal operation, thereby avoiding waste when selecting the motor, ensuring reasonable selection, and effectively reducing motor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of the present invention.

[0046] Figure 2 It is the length of the force arm from the lower edge of the sensing area to the axis of the rotating shaft.

[0047] Figure 3 Measure the distance between the vertical line of the center of gravity and the axis of the backrest shaft. DETAILED DESCRIPTION

[0048] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0049] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0050] One embodiment of the present invention provides a method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution, the flow chart of which is as follows: Figure 1The torque calculated by this method consists of two parts: the first part involves experimentally collecting body pressure distribution data from the test subject in the driving position, calculating the pressure exerted on the sensing area of ​​each backrest component and the length of the force arm relative to the backrest's rotation axis, and then calculating the torque generated at the backrest's rotation axis by the body's weight. The second part involves estimating the backrest's mass and center of gravity using computer-aided design software (CATIA), measuring the length of the gravity arm, and calculating the torque generated at the backrest's rotation axis by the seat's weight. Adding these two torque components yields the torque at the rotation axis under driving conditions.

[0051] The method specifically comprises the following steps:

[0052] Step S1: test data recording and measurement;

[0053] Conduct a test and record the static body pressure distribution data, and measure the positional relationship between the body pressure distribution area and the seat back rotation axis. The specific process is as follows:

[0054] Prepare the experimental seat, fix it on the test bench that simulates the vehicle environment, and adjust the installation position. Correctly install and fix the pressure distribution test system to ensure that the body pressure sensor covers the entire seat back, and the surface is flat, symmetrical, and wrinkle-free. Let the subject sit down, adjust the seat to a suitable position, maintain a driving or riding posture, make full contact with the seat, and lean the body naturally and relaxedly on the backrest. During the test, the subject should keep the posture unchanged, and then collect the data of the body pressure sensor on the backrest. Select a frame of relatively stable data from the static body pressure distribution data obtained for recording. Open the model data of the test seat in CATIA software, calibrate the position of the backrest shaft axis, calibrate the position of the body pressure sensor sensing area in the seat model according to the actual installation position of the body pressure sensor in the experiment, and measure the force arm length d1 (in cm) from the lower edge of the sensing area to the axis of the backrest shaft. For details, please refer to Figure 2 .

[0055] Step S2: Calculate the torque generated by the weight of the human body at the backrest rotation axis;

[0056] Based on the static body pressure distribution data, the pressure on each sensing area of ​​the backrest and the length of the force arm relative to the backrest rotation axis are calculated respectively, and the torque generated at the backrest rotation axis when the body weight acts on the backrest is calculated. The specific process is as follows:

[0057] To simplify the calculation, the area where the body pressure sensor is installed on the seat back is approximately regarded as a plane. The static body pressure distribution data of the seat back recorded in the experiment is divided into m rows and n columns, with a total of m*n measurement areas. Each area has a side length of a (unit: cm) square. Record the central pressure of each independent sensing area (where i=1,2...m; j=1,2...n) (unit: N / cm 2 ) data. Calculate the pressure of each sensing area according to the following formula :

[0058] Formula 1: ;

[0059] Since the length of the force arm of the measuring area of ​​the jth column to the axis of the backrest shaft is equal, for the convenience of calculation, the pressure of the sensing area located in the jth column is added together to obtain the pressure and F of the area in the jth column. j :

[0060] Formula 2: ;

[0061] Further deduction yields:

[0062] Formula 3: ;

[0063] The distance between the center point of the j-th column area and the lower edge of the sensing area for:

[0064] Formula 4: ;

[0065] Then the length of the force arm of the pressure in the jth column area to the axis of the backrest shaft is for:

[0066] Formula 5: ;

[0067] Further deduction yields:

[0068] Formula 6: ;

[0069] It is stipulated that the positive direction is the direction pointing to the right side of the seat along the axis of the backrest shaft, then the torque of the pressure in the jth column area on the axis of the backrest shaft is for:

[0070] Formula 7: ;

[0071] Add up the torques in the n-column area to get the torque M1 of the backrest area body pressure on the backrest shaft center:

[0072] Formula 8: ;

[0073] Further deduction yields:

[0074] Formula 9: ;

[0075] The M1 obtained in this way is the torque generated at the backrest shaft when the weight of the human body acts on the backrest under driving conditions.

[0076] Step S3: Calculate the torque generated by the weight of the seat back at the backrest rotation axis;

[0077] Estimate the mass and center of gravity of the backrest using computer-aided design software, measure the length of the gravity arm, and calculate the torque generated by the weight of the seat backrest at the backrest rotation axis. The specific process is as follows:

[0078] Open the test seat model data in CATIA software. To simplify the calculation, only the mass of the metal frame is estimated when estimating the mass of the backrest in the software (the mass of the headrest, sponge, vibration damping device and other components is selected as the mass coefficient). Select the seat back frame structure, select the material corresponding to the seat frame in the material properties, measure the inertia of the frame structure, and obtain the center of gravity coordinates of the frame structure (G x , G y , G z ), with a mass of m1 (unit: kg). In the model, coordinates (G x , G y , G z ) Determine the center of gravity of the backrest frame, draw a perpendicular line through the center of gravity to the horizontal plane, and measure the distance L2 (i.e. the length of the gravity arm, in cm) between the center of gravity and the axis of the backrest shaft. Figure 3 The estimated total mass m of the test seat backrest is:

[0079] Formula 10: ;

[0080] Then the gravity G of the backrest (select the gravity acceleration constant g=9.8N / kg) is:

[0081] Formula 11: ;

[0082] Then, the torque M2 of the seat back weight on the backrest shaft is:

[0083] Formula 12: ;

[0084] Further deduction yields:

[0085] Formula 13: ;

[0086] This is obtained , which is the torque generated by the gravity of the seat back at the backrest shaft under driving conditions.

[0087] Step S4: Calculate the total torque at the backrest shaft;

[0088] The total torque M at the seat backrest shaft is obtained by adding the torque generated at the seat backrest shaft by the weight of the human body acting on the seat backrest and the torque generated at the seat backrest shaft by the weight of the seat backrest:

[0089] Equation 14: ;

[0090] The above calculations yield the torque at the rotating shaft under driving and riding conditions. This torque value allows for the rapid and precise determination of the normal operating output torque range of the seatback angle adjustment motor, enabling accurate motor selection and minimizing resource waste and costs.

[0091] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for calculating the torque of a seat back angle adjustment mechanism based on body pressure distribution, characterized in that: The following steps are involved: Step S1: test data recording and measurement; Conduct tests and record static body pressure distribution data, measuring the positional relationship between the body pressure distribution area and the seat back rotation axis; Step S2: Calculate the torque generated by the weight of the human body at the backrest rotation axis; Based on the static body pressure distribution data, the pressure on the sensing area of ​​each part of the backrest and the length of the force arm relative to the backrest rotation axis are calculated respectively, and the torque generated at the backrest rotation axis when the human body weight acts on the backrest is calculated; Step S3: Calculate the torque generated by the weight of the seat back at the backrest rotation axis; Estimate the mass and center of gravity of the backrest using computer-aided design software, measure the length of the gravity arm, and calculate the torque generated by the weight of the seat back at the backrest rotation axis; Step S4: Calculate the total torque at the backrest shaft; The torques calculated in step S2 and step S3 are added together to obtain the total torque at the backrest angle adjustment hinge.

2. The method for calculating the torque of the seat back angle adjustment mechanism based on body pressure distribution according to claim 1, characterized in that: The specific process of step S1 is as follows: Fix the test seat on a test bench that simulates the vehicle vehicle environment, adjust the installation position and ensure that the body pressure sensor covers the entire seat back. After the test subject sits down, maintain a driving or sitting posture, collect body pressure sensor data from the backrest, and select a stable frame of data from the obtained static body pressure distribution data for recording. Open the test seat model data in computer-aided design software, calibrate the position of the backrest shaft axis and the position of the body pressure sensor sensing area, and measure the force arm length d1 from the lower edge of the sensing area to the axis of the backrest shaft.

3. The method for calculating the torque of the seat back angle adjustment mechanism based on body pressure distribution according to claim 1, characterized in that: The specific process of step S2 is as follows: The static body pressure distribution data of the backrest is divided into m rows and n columns, with a total of m*n measurement areas. Each area has a side length of a square; record the central pressure of each independent sensing area Data, where i=1,2...m; j=1,2...n; Calculate the pressure at each sensing area using the following formula: : ； The pressure of the sensing area in the jth column is added together to obtain the pressure of the jth column area and F j : ； The distance between the center point of the j-th column area and the lower edge of the sensing area for: ； Then the length of the force arm of the pressure in the jth column area to the axis of the backrest shaft is for: ； It is stipulated that the positive direction is the direction pointing to the right side of the seat along the axis of the backrest shaft, then the torque of the pressure in the jth column area on the axis of the backrest shaft is for: ； Add up the torques in the n-column area to get the torque M1 of the backrest area body pressure on the backrest shaft center: ； M1 is the torque generated at the backrest shaft when the weight of the human body acts on the backrest under driving conditions.

4. The method for calculating the torque of the seat back angle adjustment mechanism based on body pressure distribution according to claim 3, characterized in that: The specific process of step S3 is as follows: Open the test seat model data in CATIA software. When estimating the mass of the backrest, only the mass of the metal frame is estimated. The mass coefficient of the headrest, sponge, and vibration damping device components is selected. To calculate; Select the seat back frame structure, select the material corresponding to the seat frame in the material properties, measure the inertia of the frame structure, and obtain the center of gravity coordinates of the frame structure (G x , G y , G z ), with mass m1; in the model, the coordinates (G x , G y , G z ) Determine the center of gravity of the backrest frame, draw a perpendicular line through the center of gravity to the horizontal plane, and measure the distance L2 between the perpendicular line and the axis of the backrest rotation axis; estimate the total mass m of the test seat backrest as: ； Select the gravity acceleration constant g = 9.8N / kg and calculate the backrest gravity G as: ； Calculate the torque M2 of the seat back's gravity on the backrest's rotation axis: ； It is the torque generated by the weight of the seat back at the backrest rotation axis under driving conditions.

5. The method for calculating the torque of the seat back angle adjustment mechanism based on body pressure distribution according to claim 4, characterized in that: The specific process of step S4 is as follows: The total torque M at the seat backrest shaft is obtained by adding the torque generated at the seat backrest shaft by the weight of the human body acting on the seat backrest and the torque generated at the seat backrest shaft by the weight of the seat backrest: ； Based on the total torque M, determine the output torque range of the backrest angle adjustment motor during normal operation and select the motor.

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