Whole-vehicle vibration evaluation method and system for diesel fork lift truck based on human body comfort

Abstract

The invention discloses a vehicle vibration evaluation method and system for a diesel fork lift truck based on human body comfort, and relates to the technical field of vehicle vibration evaluation, and the method comprises the steps: taking a direct contact point of a human body and a fork lift truck as a to-be-tested point, obtaining the vibration initial data of each to-be-tested point, and sequentially recording the vibration data corresponding to adjacent subjective feeling boundary regions; calculating the total value of effective values of the weighted acceleration of the vibration of each to-be-measured point based on the vibration initial data; performing statistical analysis on subjective feeling vibration data, and dividing the subjective feeling section into a vibration evaluation area by using an upper limit value of a confidence section as a limit value for dividing the subjective feeling section; comparing the total weighted acceleration effective value with a limit value of the vibration evaluation area to obtain a specific area where the total weighted acceleration effective value is located in the vibration evaluation area, thereby obtaining a vibration evaluation state of the to-be-measured point; according to the method and system for evaluating the vibration of the whole diesel fork lift truck, the subjective feeling of the human body of the whole diesel fork lift truck is fully reflected by evaluating related measuring points, and the magnitude of the subjective feeling of the human body is directly expressed by using the total effective value of the weighted acceleration.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle vibration evaluation, and in particular to a vehicle vibration evaluation method and system for an internal combustion forklift based on human comfort. Background Art

[0002] One of the key indicators for evaluating the comfort of internal combustion forklifts is human vibration comfort. Currently, there are no universal industry standards for evaluating forklift vibration comfort. The primary focus of forklift vibration comfort evaluation by various OEMs or researchers is the forklift steering wheel. The forklift vibration level is quantified and evaluated by measuring the effective value of the steering wheel's vibration acceleration under certain operating conditions. However, different parts of the human body perceive different vibration frequencies differently. While some vibration levels are high, they do not fully reflect the subjective perception of the human body, making it difficult to effectively evaluate comfort. Subsequently, some researchers have conducted research to establish a correlation between the effective value of objective vibration acceleration and the subjective perception of the human body, using the objective effective value of vibration acceleration to predict the subjective comfort evaluation results.

[0003] There are still several problems in the current research results on forklift vibration evaluation: First, the vast majority of research results focus on the steering wheel measurement point, and there is a lack of research on the vibration evaluation of other forklift contact points with the human body; second, the operating conditions in previous research results are mostly concentrated on special operating conditions such as idling and overflow, and there is a lack of vibration evaluation research on forklift full-speed operating conditions; finally, previous evaluation research results only studied the correlation between the effective value of vibration acceleration and the subjective feeling of the human body, without considering the differences in the perception of different parts of the human body to different frequencies. Therefore, it is impossible to obtain a strong correlation between the two. Ultimately, objective vibration data still cannot effectively express the subjective feeling of the human body. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a vibration evaluation method and system for an internal combustion forklift based on human comfort. By evaluating relevant measuring points, the method fully reflects the subjective human feeling of the forklift, and uses the total effective value of the weighted acceleration to directly express the size of the subjective human feeling.

[0005] The present invention proposes a vibration evaluation method for an internal combustion forklift based on human comfort, comprising:

[0006] The point where the human body directly contacts the forklift is used as the test point. The initial vibration data of each test point is obtained, and the vibration data corresponding to the adjacent subjective perception boundary areas are recorded in sequence.

[0007] Calculate the total effective value of the weighted acceleration of each test point based on the initial vibration data;

[0008] Performing statistical analysis on the vibration data corresponding to the subjective perception of each test point, using the upper limit of the confidence interval as the limit for dividing the subjective perception vibration evaluation interval, thereby dividing each test point into vibration evaluation areas, wherein the vibration evaluation areas include a low vibration area, a significant vibration area, and a high vibration area;

[0009] Compare the total effective value of the weighted acceleration of each test point with the limit value of the vibration evaluation area to obtain the specific area where the total effective value of the weighted acceleration of each test point is located in the vibration evaluation area, thereby obtaining the vibration evaluation status of the test point.

[0010] Furthermore, when the point of direct contact between the human body and the forklift is used as the test point,

[0011] When the driver maintains a normal driving posture on the forklift, four test points are set, namely: the contact position between the feet and the forklift footboard, the contact position between the buttocks and the upper surface of the seat, the contact position between the back and the seat backrest, and the contact position between the hands and the steering wheel.

[0012] Furthermore, in obtaining the initial vibration data of each test point, the time-domain transient values of the vibration acceleration in three directions of the test point from the idling stage to the full-speed stage are collected.

[0013] Furthermore, the acquisition process of the time-domain transient value of vibration acceleration is as follows:

[0014] Place the accelerometers at the points to be measured. For the contact points between the foot and the forklift footboard, the buttocks and the seat top surface, and the hands and the steering wheel, the x-direction points in front of and behind the driver, the y-direction points to the left and right sides of the driver, and the z-direction points up and down. For the contact point between the back and the seat backrest, the x-direction points in front of and below the driver, the y-direction points to the left and right sides of the driver, and the z-direction points in front of and behind the driver.

[0015] The driver maintains a standard sitting posture. After the collection begins, the driver's hands must not touch the steering wheel. The vibration acceleration time domain transient value at idle stage is collected continuously for 5-10 seconds.

[0016] The driver then depresses the accelerator pedal slowly and evenly, so that the acceleration from the idle stage to the full speed stage takes no less than 30 seconds, and the time-domain transient value of the vibration acceleration during this period is collected;

[0017] After reaching the full speed stage, continuously collect the time domain transient value of vibration acceleration for 5-10 seconds;

[0018] End the acquisition and release the accelerator pedal;

[0019] The acquisition process from the idle stage to the full speed stage was cycled at least three times to remove occasional interference and select normal data.

[0020] Furthermore, the weighted acceleration time domain value of the vibration of each test point is calculated based on the initial vibration data, and then the total effective value of the weighted acceleration of the vibration of each test point is calculated based on the weighted acceleration time domain value, wherein the weighted acceleration time domain value refers to the frequency weighted processing of the initial vibration data obtained from different test points, specifically:

[0021] When the point to be measured is the contact position between the foot and the forklift sole, the vibration acceleration in the x, y, and z directions of the sole measurement point where both feet touch is selected as W k Perform frequency weighting processing;

[0022] When the point to be measured is the contact position between the buttocks and the upper surface of the seat, the vibration acceleration in the z direction of the seat surface measurement point is W k Perform frequency weighting processing, and the vibration acceleration in the x and y directions is W d Perform frequency weighting processing;

[0023] When the point to be measured is the contact position between the back and the seat back, the vibration acceleration in the x direction of the backrest measurement point is W c Perform frequency weighting processing, using W in the x and y directions d Perform frequency weighting processing;

[0024] When the hand is in contact with the steering wheel at the test point, the vibration acceleration in the x, y, and z directions of the steering wheel test point where the arm contacts the steering wheel is selected as W. h Perform frequency weighting processing.

[0025] Furthermore, when calculating the weighted acceleration time domain value of each test point based on the initial vibration data, when the test point is the contact position between the buttocks and the upper surface of the seat, the influence of the driver's weight change on the seat vibration test result is corrected by the weight influence coefficient δ.

[0026] Furthermore, the total effective value A of the weighted acceleration of each test point is calculated based on the weighted acceleration time domain value. W The specific calculation formula is as follows:

[0027]

[0028] Among them, k x 、k y 、k z are the axial coefficients of the measured point in the x, y, and z directions, are the time domain values of the weighted acceleration of the measured point in the x, y, and z directions respectively.

[0029] Furthermore, when the point to be measured is not the contact position between the buttocks and the upper surface of the seat, the weight influence coefficient δ is set to 0.

[0030] Furthermore, in the statistical analysis of the vibration data of the subjective perception of each test point, the upper and lower limits of the confidence interval are used as the limits for dividing the subjective perception vibration evaluation interval, specifically:

[0031] The evaluators controlled the forklift's throttle and searched for the boundary areas of adjacent subjective feelings at different speeds. Each sampling period lasted no less than 10 seconds to obtain statistical samples.

[0032] Utilizing statistical tools and a mean confidence interval method to statistically analyze the statistical sample and obtain a statistical sample that meets a set confidence threshold;

[0033] The upper and lower limits based on the set confidence threshold are calculated by using the sample mean, standard deviation and t value, and the upper and lower limits are used as the vibration evaluation limit values of the current adjacent subjective perception boundary area.

[0034] A vibration evaluation system for an internal combustion forklift based on human comfort, comprising a data acquisition module, a calculation module, a statistical division module and a judgment module;

[0035] The data acquisition module is used to use the point of direct contact between the human body and the forklift as the test point, obtain the initial vibration data of each test point, and sequentially record the vibration data corresponding to the adjacent subjective perception boundary areas;

[0036] The calculation module is used to calculate the weighted acceleration time domain value of each test point based on the initial vibration data;

[0037] The statistical division module is used to perform statistical analysis on the vibration data of the subjective perception of each test point, and use the upper and lower limits of the confidence interval as the limits of the subjective perception vibration evaluation interval, thereby dividing it into vibration evaluation areas, which include a small vibration area, an obvious vibration area, and a large vibration area;

[0038] The determination module is used to compare the weighted acceleration time domain value with the upper and lower limits of the vibration evaluation area, and obtain the specific area where the weighted acceleration time domain value is located in the vibration evaluation area, thereby obtaining the vibration evaluation state of the test point.

[0039] The advantages of the human comfort-based internal combustion forklift vehicle vibration evaluation method and system provided by the present invention include: using four measuring points in contact with the human body as reference points for the internal combustion forklift vehicle vibration comfort evaluation. Compared to vibration evaluation focusing solely on the steering wheel measuring point, this method more fully reflects the impact of vehicle vibration on human comfort. Furthermore, a weight correction factor is introduced to correct the impact of weight changes on vibration measurements at the seat measuring point, thereby developing a specific method for collecting initial forklift vibration evaluation data. Taking into account the human body's perception differences in different frequencies, this embodiment applies frequency-weighted processing based on human comfort to the vibration data of measuring points across the entire speed range from idle to full speed. This ensures a strong correlation between the vibration values of the measuring points and the human subjective perception, allowing for the evaluation of vibration levels at the measuring points across the entire speed range. Acceleration data samples from two adjacent subjective perception boundary zones are sampled and statistically analyzed, and the upper limit of the confidence interval is used as the vibration limit for the adjacent subjective perception interval. This allows for clearer demarcation of the subjective perception intervals and avoids statistical blind spots. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the process of the present invention;

[0041] Figure 2 This is a schematic diagram of the collection locations of the four measurement points;

[0042] Figure 3 This is a curve of the total effective value of the weighted acceleration of a certain car's steering wheel. DETAILED DESCRIPTION

[0043] The technical solutions of the present invention are described in detail below through specific embodiments. Numerous specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] like Figures 1 to 3 As shown in the figure, the present invention proposes a vibration evaluation method for an internal combustion forklift based on human comfort. The vibration data is collected and post-processed to obtain the total effective value of the weighted acceleration based on human comfort at the four measuring points of the forklift steering wheel, footrest, backrest and seat from idle to full speed. The total value curve is placed in the designated subjective evaluation range for evaluation.

[0045] The vibration evaluation method includes steps one to four:

[0046] Step 1: Take the point where the human body directly contacts the forklift as the test point, obtain the initial vibration data of each test point, and record the vibration data corresponding to the adjacent subjective perception boundary areas in sequence;

[0047] When the driver maintains a normal driving posture on the forklift, his feet are in contact with the forklift footboard, his buttocks are in contact with the upper surface of the seat, his back is in contact with the seat back, and his hands are in contact with the steering wheel. Figure 2 These four measurement points are the points of direct contact between the human body and the forklift. Forklift vibrations are essentially transmitted to the human body through these four measurement points, and the magnitude of vibration at these locations directly affects the human body's subjective perception. Therefore, to fully evaluate the vibration condition of the entire forklift, this embodiment selects the steering wheel, footrest, seat and backrest as the evaluation measurement points, namely, the contact point between the foot and the forklift footrest, the contact point between the buttocks and the seat top surface, the contact point between the back and the seat backrest, and the contact point between the hand and the steering wheel.

[0048] Step 2: Calculate the total effective value of the weighted acceleration of each test point based on the initial vibration data; specifically:

[0049] Accelerometers are placed at the points to be measured. For the contact points between the foot and the forklift footboard, the buttocks and the seat top, and the hands and the steering wheel, the x-direction points in front of and behind the driver, the y-direction points to the left and right sides, and the z-direction points up and down. For the contact point between the back and the seat backrest, the x-direction points in front of and below the driver, the y-direction points to the left and right sides, and the z-direction points in front of and behind the driver. The driver maintains a standard sitting posture. After the acquisition begins, the driver's hands must not touch the steering wheel. The vibration acceleration time-domain transient values of the idling stage are continuously collected for 5-10 seconds. The driver then slowly and evenly presses the accelerator pedal so that the acceleration from the idling stage to the full speed stage lasts for no less than 30 seconds. The vibration acceleration time-domain transient values during this period are collected. After reaching the full speed stage, the vibration acceleration time-domain transient values are continuously collected for 5-10 seconds. The acquisition ends and the accelerator pedal is released. The acquisition process from the idling stage to the full speed stage is repeated at least three times to eliminate occasional interference and select normal data.

[0050] At present, people tend to ignore the differences in human body's subjective perception of different vibration frequencies, and directly use the time domain transient value of vibration acceleration in the three directions of X / Y / Z to obtain the time domain root mean square value a x 、a y 、a z , and finally calculate the total RMS value The A value is used to measure the vibration magnitude of the measuring point. This data processing method is similar to the linear superposition of the effective vibration values in the three directions of the measuring point. The final total vibration value A cannot effectively reflect the changes in the subjective comfort felt by the human body.

[0051] This embodiment sets frequency weighting for the initial vibration data obtained at each of the four test points set above to evaluate the impact of vibration on human health, comfort, vibration perception, etc. Specifically, when the test point is the contact position between the foot and the forklift sole, the vibration acceleration in the x, y, and z directions of the sole measurement point where both feet touch is selected as W. k Perform frequency weighting processing; when the point to be measured is the contact position between the buttocks and the upper surface of the seat, the vibration acceleration in the z direction of the seat surface measurement point is W k Perform frequency weighting processing, and the vibration acceleration in the x and y directions is W d Perform frequency weighting processing; when the point to be measured is the contact position between the back and the seat back, the vibration acceleration in the x direction of the backrest measurement point is W c Perform frequency weighting processing, using W in the x and y directions d Perform frequency weighting processing; when the hand is in contact with the steering wheel at the test point, the vibration acceleration in the x, y, and z directions of the steering wheel test point where the arm contacts the steering wheel is selected as W. h Perform frequency weighting processing and use the frequency weighted data as the weighted acceleration time domain value of each test point vibration. Then calculate the total effective value A of the weighted acceleration of each test point vibration based on the weighted acceleration time domain value. W , see Table 1 for details:

[0052] Table 1

[0053]

[0054] In Table 1, W i The value of i in the equation (i) can be k, d, c, or h, corresponding to different weighting functions. Frequency-weighted processing of the time-domain transient acceleration data (initial vibration data) at the measuring point can be performed in professional data processing software (such as Matlab). After frequency weighting, the effective value in the time domain is calculated. When calculating the total value in the time domain, the axial coefficient k must be added to the vibration acceleration along different axes at the measuring point. The values of the axial coefficient k are shown in Table 2.

[0055] Table 2

[0056] Measuring point location X direction Y direction Z direction Seat surface 1 1 1 Backrest surface 0.8 0.5 0.4 Foot contact surface 0.25 0.25 0.4 steering wheel 1 1 1

[0057] Since the forklift seat is installed on the hood, which is a thin plate structure, it is affected by the driver's weight, and its different deformations will have a significant impact on the vibration measurement. This embodiment introduces the weight influence coefficient δ, as shown in Table 3, to correct the impact of the driver's weight change on the seat vibration test results. This coefficient δ is only valid for the vibration calculation of the seat measurement point. When calculating the steering wheel, footrest and backrest measurement points, δ takes the value of 0.

[0058] Table 3

[0059] coefficient Q≤75kg <h2 style=";text-align:left;direction:ltr">75kg <Q≤100kg <h2 style=";text-align:left;direction:ltr"> 100kg<Q δ 0 0.05 0.15

[0060] Where Q is the current driver's weight. The specific value of the coefficient δ is set according to the driver's actual weight, so as to more effectively correct the impact of the driver's weight change on the seat vibration test results.

[0061] The calculation formula of the total effective value of the weighted acceleration of the measuring point vibration is as follows:

[0062]

[0063] Among them, k x 、k y 、k z are the axial coefficients of the measured point in the x, y, and z directions, are the time-domain values of the weighted acceleration of the measured point in the x, y, and z directions after weighting the initial vibration data frequency, and δ is the weight influence coefficient.

[0064] Step 3: Statistically analyzing the vibration data corresponding to the subjective feelings of each test point, using the upper limit of the confidence interval as the limit of dividing the subjective vibration evaluation interval, thereby dividing the vibration evaluation area of each test point into vibration evaluation areas, wherein the vibration evaluation areas include a relatively small vibration area, an obvious vibration area, and a relatively large vibration area;

[0065] To establish the correlation between the total effective value of weighted acceleration and subjective human perception, and to express subjective evaluation results using vibration data, this embodiment establishes a subjective evaluation method for forklift comfort for the first time. This evaluation method includes several evaluation team members and several forklift prototypes to be evaluated. The forklift evaluation operating condition is the stationary acceleration process (idling to full speed). The evaluation measurement points are the four points mentioned above, and the subjective perception is divided into three regions: ① low vibration (little or no discomfort); ② significant vibration (discomfort is present and acceptable); and ③ high vibration (high discomfort is strong and unbearable for a long time). Specifically, the vibration data corresponding to adjacent subjective perception boundary regions are recorded, specifically the interval vibration data when the subjective state transitions from low vibration to significant vibration, and the interval vibration data when the subjective state transitions from significant vibration to high vibration. Existing technologies use subjective perception estimation as a method for determining vibration evaluation, but this method is relatively subjective and the evaluation results are subject to significant discrepancies. This embodiment performs statistical analysis based on the interval vibration data under subjective perception to obtain the interval vibration data under objective conditions, thereby improving the accuracy of vibration evaluation.

[0066] When collecting data, people are accustomed to directly collecting the vibration acceleration values corresponding to the above three subjective feeling intervals as statistical analysis samples to divide the subjective evaluation data intervals. However, this method is prone to creating "blind zones" between two adjacent subjective evaluation intervals. For example, according to the above method, the acceleration interval with relatively small subjective vibration may be in [0, 1.8], and if the vibration acceleration interval with obvious vibration is in [1.9, 3], then there will be an evaluation blind zone between (1.8, 1.9).

[0067] To avoid such problems, in this embodiment, it is stipulated that the collected sample is the vibration data corresponding to the boundaries of two adjacent subjective feeling regions. Finally, statistical analysis is performed on this sample data, and the upper limit value of the confidence interval is used as the limit value for dividing the subjective feeling interval. The specific operation method is as follows:

[0068] The evaluator controls the forklift throttle to find the boundary regions of the above two adjacent subjective feelings at different rotational speeds, such as the boundary region where the subjective feeling changes from relatively small to obvious vibration, or the boundary region where the vibration changes from obvious to large. Each collection time is not less than 10s. Using the statistical tool of the WPS spreadsheet function, the method of mean confidence interval is used to statistically analyze this data sample. For example, if the significance level of the sample data is set to 0.05, that is, the confidence level is 95%, the mean and standard deviation are calculated based on the AVERAGE and STDEV functions, the t-value is calculated using the TINV function, and finally the upper and lower limits of the interval based on the 95% confidence level are calculated using the sample mean, standard deviation, and t-value.

[0069] Taking the statistical data of the steering wheel vibration sample as an example, as shown in Table 4, the upper or lower limit of the estimated confidence interval can be taken as the boundary division of the corresponding critical interval (in this embodiment, the upper limit value is taken). Then, the boundary limit value for the change from relatively small subjective feeling to obvious vibration at the steering wheel measurement point is 2.6 m / s 2 , then Aw ≤ 2.6 m / s 2 is taken as the region with relatively small vibration. Then, 2.6 m / s 2 < Aw ≤ 4.5 m / s 2 is taken as the region with obvious vibration. The boundary limit value for the change from obvious vibration to large vibration is 4.5 m / s 2 , then 4.5 m / s 2 < Aw is taken as the region with large vibration. The evaluation limit interval division method for other measurement points is the same. Finally, the total value curve of the frequency-weighted vibration acceleration is placed into the subjective evaluation region. As Figure 3 shown, it is a graph of the total effective value of the weighted acceleration of a certain sample vehicle's steering wheel, with the rotational speed range from idle speed to full speed. From the graph, the steering wheel vibration value and the corresponding subjective feeling interval at a certain rotational speed point can be directly seen.

[0070] Table 4

[0071]

[0072] Step 4: Compare the total effective value of the weighted acceleration of each test point with the limit value of the vibration evaluation area to obtain the specific area where the total effective value of the weighted acceleration of each test point is located in the vibration evaluation area, thereby obtaining the vibration evaluation status of the test point.

[0073] After dividing the vibration evaluation area corresponding to each test point obtained in step 3, based on the calculated total effective value of weighted acceleration, it can be determined in which vibration evaluation area the total effective value of weighted acceleration falls, thereby obtaining the vibration evaluation of each test point.

[0074] The first problem that this evaluation method needs to solve is to fully reflect the subjective feeling of the human body of the forklift by evaluating relevant measuring points. The evaluation conditions should include the entire speed range of the forklift. At the same time, the total effective value of the weighted acceleration can directly express the size of the human body's subjective feeling.

[0075] This embodiment uses four measuring points in contact with the human body as reference points for the vibration comfort evaluation of the internal combustion forklift. Compared with the vibration evaluation of the steering wheel measuring point only, it can more fully reflect the impact of the vibration of the whole vehicle on human comfort. In addition, a weight correction coefficient is introduced to correct the impact of weight changes on the vibration measurement of the seat measuring point, thereby formulating a specific method for collecting data for the initial vibration evaluation of the forklift. In view of the fact that the human body has different perceptions of different frequencies, this embodiment performs frequency weighting processing based on human comfort on the vibration data of the measuring points in the entire speed range from idle to full speed, so that the vibration values of the measuring points are strongly correlated with the subjective feelings of the human body, and the vibration levels of the measuring points in the entire speed range can be examined and evaluated. The acceleration data samples of the two adjacent subjective feeling boundary areas are sampled and statistically analyzed, and the upper limit of the confidence interval is used as the vibration limit value of the adjacent subjective feeling interval. This can make the division of the subjective feeling interval clearer and avoid statistical blind spots.

[0076] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A vibration evaluation method for an internal combustion forklift based on human comfort, characterized in that: include: The point where the human body directly contacts the forklift is used as the test point. The initial vibration data of each test point is obtained, and the vibration data corresponding to the adjacent subjective perception boundary areas are recorded in sequence. Calculate the total effective value of the weighted acceleration of each test point based on the initial vibration data; Performing statistical analysis on the vibration data corresponding to the subjective perception of each test point, using the upper limit of the confidence interval as the limit for dividing the subjective perception vibration evaluation interval, thereby dividing each test point into vibration evaluation areas, wherein the vibration evaluation areas include a low vibration area, a significant vibration area, and a high vibration area; Compare the total effective value of the weighted acceleration of each test point with the limit value of the vibration evaluation area to obtain the specific area where the total effective value of the weighted acceleration of each test point is located in the vibration evaluation area, thereby obtaining the vibration evaluation status of the test point.

2. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 1 is characterized in that: When the point of direct contact between the human body and the forklift is used as the test point, When the driver maintains a normal driving posture on the forklift, four test points are set, namely: the contact position between the feet and the forklift footboard, the contact position between the buttocks and the upper surface of the seat, the contact position between the back and the seat backrest, and the contact position between the hands and the steering wheel.

3. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 1 is characterized in that: In obtaining the initial vibration data of each test point, the time domain transient values of the vibration acceleration in three directions of the test point from the idling stage to the full speed stage are collected.

4. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 2 is characterized in that: The acquisition process of the time-domain transient value of vibration acceleration is as follows: Place the accelerometers at the points to be measured. For the contact points between the foot and the forklift footboard, the buttocks and the seat top surface, and the hands and the steering wheel, the x-direction points in front of and behind the driver, the y-direction points to the left and right sides of the driver, and the z-direction points up and down. For the contact point between the back and the seat backrest, the x-direction points in front of and below the driver, the y-direction points to the left and right sides of the driver, and the z-direction points in front of and behind the driver. The driver maintains a standard sitting posture. After the collection begins, the driver's hands must not touch the steering wheel. The vibration acceleration time domain transient value at idle stage is collected continuously for 5-10 seconds. The driver then depresses the accelerator pedal slowly and evenly, so that the acceleration from the idle stage to the full speed stage takes no less than 30 seconds, and the time-domain transient value of the vibration acceleration during this period is collected; After reaching the full speed stage, continuously collect the time domain transient value of vibration acceleration for 5-10 seconds; End the acquisition and release the accelerator pedal; The acquisition process from the idle stage to the full speed stage was cycled at least three times to remove occasional interference and select normal data.

5. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 2 is characterized in that: In calculating the weighted acceleration time domain value of vibration of each test point based on the initial vibration data, the weighted acceleration time domain value of vibration of each test point is calculated based on the initial vibration data, and then the total effective value of the weighted acceleration of vibration of each test point is calculated based on the weighted acceleration time domain value, wherein the weighted acceleration time domain value refers to frequency weighted processing of the initial vibration data obtained from different test points, specifically: When the point to be measured is the contact position between the foot and the forklift sole, the vibration acceleration in the x, y, and z directions of the sole measurement point where both feet touch is selected as W k Perform frequency weighting processing; When the point to be measured is the contact position between the buttocks and the upper surface of the seat, the vibration acceleration in the z direction of the seat surface measurement point is W k Perform frequency weighting processing, and the vibration acceleration in the x and y directions is W d Perform frequency weighting processing; When the point to be measured is the contact position between the back and the seat back, the vibration acceleration in the x direction of the backrest measurement point is W c Perform frequency weighting processing, using W in the x and y directions d Perform frequency weighting processing; When the hand is in contact with the steering wheel at the test point, the vibration acceleration in the x, y, and z directions of the steering wheel test point where the arm contacts the steering wheel is selected as W. h Perform frequency weighting processing.

6. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 5 is characterized in that: When calculating the weighted acceleration time domain value of each test point based on the initial vibration data, when the test point is the contact position between the buttocks and the upper surface of the seat, the influence of the driver's weight change on the seat vibration test results is corrected by the weight influence coefficient δ.

7. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 6 is characterized in that: The total effective value A of the weighted acceleration of each test point is calculated based on the weighted acceleration time domain value. W The specific calculation formula is as follows: Among them, k x 、k y 、k z are the axial coefficients of the measured point in the x, y, and z directions, are the time domain values of the weighted acceleration of the measured point in the x, y, and z directions respectively.

8. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 7 is characterized in that: When the point to be measured is not the contact position between the buttocks and the upper surface of the seat, the weight influence coefficient δ is set to 0.

9. The internal combustion forklift vehicle vibration evaluation method based on human comfort according to claim 1, characterized in that: In the statistical analysis of the vibration data of the subjective perception of each test point, the upper limit of the confidence interval is used as the limit value for dividing the subjective perception vibration evaluation interval, specifically: The evaluators controlled the forklift's throttle and searched for the boundary areas of adjacent subjective feelings at different speeds. Each sampling period lasted no less than 10 seconds to obtain statistical samples. Utilizing statistical tools and a mean confidence interval method to statistically analyze the statistical sample and obtain a statistical sample that meets a set confidence threshold; The upper and lower limits based on the set confidence threshold are calculated by using the sample mean, standard deviation and t value, and the upper limit is used as the vibration evaluation limit of the current adjacent subjective perception boundary area.

10. A vehicle vibration evaluation system for internal combustion forklifts based on human comfort, characterized in that: It includes data acquisition module, calculation module, statistical division module and judgment module; The data acquisition module is used to use the point of direct contact between the human body and the forklift as the test point, obtain the initial vibration data of each test point, and sequentially record the vibration data corresponding to the adjacent subjective perception boundary areas; The calculation module is used to calculate the weighted acceleration time domain value of each test point based on the initial vibration data; The statistical division module is used to perform statistical analysis on the vibration data of the subjective perception of each test point, and use the upper and lower limits of the confidence interval as the limits of the subjective perception vibration evaluation interval, thereby dividing it into vibration evaluation areas, which include a small vibration area, an obvious vibration area, and a large vibration area; The determination module is used to compare the weighted acceleration time domain value with the upper and lower limits of the vibration evaluation area, and obtain the specific area where the weighted acceleration time domain value is located in the vibration evaluation area, thereby obtaining the vibration evaluation state of the test point.

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