Trailer traction test device and method

Abstract

The invention discloses a trailer traction testing device and method, relates to the technical field of trailer traction testing, and aims to solve the technical problem that the mechanical property of a traction pin under complex working conditions is inconvenient to comprehensively detect in the prior art. Mechanical sensors are arranged on the inner hole wall of the test saddle and the inner wall of the spring bolt in the axis direction, and the tractor test saddle is connected with a trailer traction pin; s2, test working condition setting: setting constant-speed advancing and constant-speed reversing working conditions; and S3, constant-speed traction working condition testing is conducted, the tractor is started and runs according to the set constant-speed advancing working condition, pressure detection is conducted on the rear side surface of the traction pin through a mechanical sensor arranged on the inner wall of the spring bolt, a tractor driver adjusts the running angle according to the running path, and the relative positions of the traction pin and the mechanical sensor cover all detection areas. The method has the advantage of evaluating the mechanical property of the traction pin under the complex working condition.

Description

Technical Field

[0001] The present invention relates to the technical field of trailer towing test, and more specifically, to a trailer towing test device and method. Background Art

[0002] In the field of trailer traction performance testing, the prior art usually uses simple tensile testing equipment to test the basic mechanical properties of the connecting parts between the trailer and the tractor. This traditional testing method generally applies tensile force through a mechanical device under specific static conditions to measure the bearing capacity of the traction pin and other components in a single force direction, so as to evaluate whether it meets the basic use requirements. For example, some testing equipment can only fix the position of the traction pin, apply a stable tensile force to the tractor, observe the deformation of the traction pin or measure the maximum tensile force it can withstand.

[0003] However, this traditional detection technology has obvious shortcomings: it cannot comprehensively detect the mechanical properties of the towing pin under actual complex working conditions, especially the changes in the force on the towing pin surface caused by angle changes, speed changes and different driving directions during the driving of the tractor. It is difficult to accurately detect potential dent damage on the towing pin surface, and it is impossible to conduct a scientific and quantitative assessment of the safety level of the towing pin, which is extremely unfavorable for ensuring the safety of the connection between the trailer and the tractor.

[0004] In view of this, we propose a trailer towing test device and method. Summary of the invention

[0005] The object of the present invention is to provide a trailer towing test device and method to solve the technical problem that the prior art is not convenient for comprehensively testing the mechanical properties of a towing pin under complex working conditions.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a trailer towing test method, comprising the following steps: S1, preparation stage, remove the original traction saddle of the tractor to be tested, replace it with a test saddle, arrange mechanical sensors along the axis direction on the inner wall of the test saddle and the inner wall of the lock tongue, and connect the tractor test saddle with the trailer traction pin; S2, test condition setting, setting the uniform forward speed and uniform reverse speed conditions; S3, uniform speed traction condition test, the tractor is started and drives at the set uniform speed forward condition, and the pressure on the rear surface of the traction pin is detected by using the mechanical sensor arranged on the inner wall of the lock tongue. The tractor driver adjusts the driving angle according to the driving path so that the relative position of the traction pin and the mechanical sensor covers each detection area; S4. Uniform reverse driving condition test: The tractor starts and drives according to the set uniform reverse driving condition. The pressure on the front surface of the kingpin is detected by using the mechanical sensors arranged on the inner wall of the test saddle. The tractor driver adjusts the driving angle according to the driving path so that the relative position between the kingpin and the mechanical sensors covers each detection area. S5. Data analysis: Obtain the pressure data collected in steps S3 and S4, filter the collected data, and identify the indentation damage on the kingpin surface. S6. Safety assessment: Quantify the damage characteristics and evaluate the safety level of the kingpin.

[0007] Preferably, in S1, the mechanical sensor groups on the inner wall of the test saddle and the inner wall of the locking tongue are arranged opposite to each other. When connecting the trailer to the tractor, use a clearance measuring ruler with an accuracy of 0.1 mm to check the clearance at the connection part to ensure that the clearance value is within the standard range .

[0008] Preferably, in S3 and S4, the tractor driver adjusts the driving angle according to the driving path to meet , where is the maximum angle of the tractor swinging to the left, is the maximum angle of the tractor swinging to the right. The driver slowly turns the steering wheel to make the driving trajectory of the tractor change in a small arc, changing the relative position between the kingpin and the mechanical sensors to ensure that each detection area divided along the axis direction of the kingpin surface is at least swept by the mechanical sensors once.

[0009] Preferably, in S5, the data filtering processing method adopts the wavelet transform algorithm, and its transformation formula is: ; where is the original pressure signal, is the scale parameter, is the translation parameter, is the wavelet basis function; The discrete wavelet transform is the discretization of the continuous wavelet transform in terms of scale and translation. For the discrete sequence , its discrete wavelet transform is expressed as: ; where , is the discretized wavelet basis function, is the normalization factor, is the discrete time sequence number, is the length of the sequence, is the discrete index of the scale factor, The discrete index of the translation factor, which is used to determine the position of the wavelet function on the discrete time axis.

[0010] Preferably, in the step S5, the specific method for identifying the indentation damage on the surface of the towing pin is as follows: determining the position and quantity of the indentation damage through a preset pressure data missing identification algorithm based on threshold comparison, and the pressure data threshold , where is obtained by statistically averaging the pressure data collected from the towing pin under normal conditions under the same test conditions, representing the average level of the surface pressure of the towing pin under normal conditions, represents the standard deviation of the pressure data, represents the coefficient determined according to the misjudgment rate requirement and the test reliability requirement; When the processed pressure data satisfies , it is determined that there is indentation damage at this position.

[0011] Preferably, in the step S6, the method for quantifying the damage characteristics is as follows: Calculating the damage density , , , where represents the quantity of indentation damage on the outer surface of the towing pin, represents the outer surface area of the towing pin, represents the bottom radius of the towing pin, represents the length of the towing pin; The method for rating the safety level of the towing pin is as follows: Rating the safety level based on a neural network model. The model adopts a multi-layer perceptron structure. The input layer receives the damage characteristic data obtained from the data analysis, including the position, quantity, and density of the indentation damage. The model outputs the safety level , where represents the activation function, represents the weight, which is updated through the backpropagation algorithm, , represents the update amount of the weight, represents the input value of the th neuron in the input layer, represents the bias term, represents the learning rate, represents the loss function calculated through the cross-entropy loss function, , represents the true label, represents the model prediction value. The model is trained with a large amount of towing pin data with known safety states and damage characteristics to improve the accuracy and reliability of the model.

[0012] Preferably, in S6, a safety level determination criterion is set: Let the safety level score be obtained by linearly transforming the safety level output by the model through a linear transformation function , that is, . Among them, and are fitting coefficients, which are determined by performing linear regression analysis on the safety level output by the model for these samples and the corresponding actual safety level scores to minimize the error between the actual score and the transformed score; and When < , it is determined that the drawbar pin is in a safe state; When < , it is determined that the drawbar pin is in an unsafe state; Among them,

[0013] is the safety level score threshold determined in advance through a large amount of experimental data and industry standards.

[0013] A trailer towing test device includes a test saddle. An inner hole wall is formed inside the test saddle. A drawbar pin is detachably arranged inside the inner hole wall. A locking tongue for locking and limiting the drawbar pin is movably arranged inside the test saddle.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. By designing mechanical sensors arranged along the axial direction on the inner hole wall of the test saddle and the inner wall of the locking tongue, and setting a method of testing under the conditions of uniform forward movement and uniform reverse movement, the present invention can comprehensively detect the surface pressure change of the drawbar pin under different conditions during actual driving, accurately identify the surface indentation damage of the drawbar pin, and effectively solve the problem that the prior art cannot comprehensively detect the mechanical properties of the drawbar pin under complex conditions.

[0015] 2. The present invention uses the wavelet transform algorithm to filter the collected data, removing the noise generated by factors such as vehicle vibration and electromagnetic interference, making the detection data more accurate and reliable, further improving the accuracy of identifying the surface indentation damage of the drawbar pin, and thus more accurately evaluating the mechanical properties of the drawbar pin under complex conditions.

[0016] 3. The present invention evaluates the safety level of the drawbar pin based on a neural network model and sets a reasonable safety level determination criterion. By quantifying the damage characteristics, it can scientifically and quantitatively evaluate the safety status of the drawbar pin. Compared with the prior art, it provides a more reliable guarantee for the safety of the connection between the trailer and the tractor, and further ensures the safe use of the drawbar pin under complex conditions. Description of the Drawings

[0017] Figure 1 It is a schematic flow chart of the method of the present invention; Figure 2 It is a schematic structural diagram of the traction saddle and the traction pin of the present invention in a mating state.

[0018] Explanation of the reference numerals in the figure: 1. Test saddle; 2. Inner hole wall; 3. Traction pin; 4. Lock tongue. Specific implementation manners

[0019] To facilitate the understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings of the specification.

[0020] Example 1. As Figure 1 shown, the present invention provides a trailer traction test method, including the following steps: S1. Preparation stage: Remove the original traction saddle of the tractor to be tested, replace it with a test saddle, arrange mechanical sensors along the axial direction on the inner hole wall of the test saddle and the inner wall of the lock tongue, and connect the test saddle of the tractor to the trailer traction pin; S2. Test condition setting: According to the actual use scenario and industry standards, set the constant speed forward and constant speed reverse conditions, determine the speed range, and ensure that the deviation between the actual speed and the set speed is within the allowable range through a speed closed-loop control system; S3. Constant speed traction condition test: The tractor starts and travels according to the set constant speed forward condition, uses the mechanical sensor arranged on the inner wall of the lock tongue to detect the pressure on the rear surface of the traction pin, and the tractor driver adjusts the driving angle according to the driving path so that the relative position of the traction pin and the mechanical sensor covers each detection area; S4. Constant speed reverse condition test: The tractor starts and travels according to the set constant speed reverse condition, uses the mechanical sensor arranged on the inner hole wall of the test saddle to detect the pressure on the front surface of the traction pin, and the tractor driver adjusts the driving angle according to the driving path so that the relative position of the traction pin and the mechanical sensor covers each detection area; S5. Data analysis: Obtain the pressure data collected in steps S3 and S4, filter the collected data, and identify the indentation damage on the surface of the traction pin; S6. Safety assessment: Quantify the damage characteristics and evaluate the safety level of the traction pin.

[0021] In the embodiment of the present invention, in S1, the mechanical sensor groups on the inner hole wall of the test saddle and the inner wall of the lock tongue are arranged oppositely; When connecting the trailer and the tractor, use a clearance measuring ruler with an accuracy of 0.1 mm to check the clearance of the connection part to ensure that the clearance value is within the standard range , this standard range is determined by the connection design specifications of the trailer and the tractor; Measure the output torque of the tractor engine through an engine comprehensive performance detector and rotational speed , and use the power system power formula to calculate the power of the power system to ensure , where is determined according to the minimum power requirement for testing and the power demand when the vehicle is running at full load; By installing torque sensors and rotational speed sensors on the input shaft and output shaft of the transmission system, measure the input power and output power , and use the transmission system efficiency formula to calculate the transmission system efficiency to ensure , where is determined based on the industry standard efficiency value of the same type of transmission system, so as to ensure that the vehicle can drive normally.

[0022] In the embodiment of the present invention, in S3 and S4, the tractor driver adjusts the driving angle according to the driving path which needs to satisfy , where is the maximum angle for the tractor to swing to the left, is the maximum angle for the tractor to swing to the right. The driver slowly turns the steering wheel to make the driving trajectory of the tractor change in a small arc, changing the relative position between the kingpin and the mechanical sensor, and ensuring that each detection area divided along the axis direction of the kingpin surface is swept by the mechanical sensor at least once.

[0023] In the embodiment of the present invention, in S5, the data filtering processing method adopts the wavelet transform algorithm, and its transformation formula is: ; where is the original pressure signal, that is, the signal of the pressure on the kingpin surface collected by the mechanical sensor and changing with time without being processed, is the scale parameter, which is used to control the stretching of the wavelet function. Different scales correspond to different frequency components. Larger scales correspond to low-frequency components, and smaller scales correspond to high-frequency components, is the translation parameter, which is used to control the translation of the wavelet function on the time axis. Changing the value of b can make the wavelet function analyze the signal at different time positions, is the wavelet basis function, which is a function with finite duration and oscillation characteristics, represents its complex conjugate form; The discrete wavelet transform is the discretization of the continuous wavelet transform in terms of scale and translation. For the discrete sequence , and its discrete wavelet transform is expressed as: ; Wherein, is the discretized wavelet basis function, is the normalization factor, is the discrete time sequence number, is the length of the sequence, is the discrete index of the scale factor, corresponding to different scale levels, reflecting different frequency resolutions of the signal, The discrete index of the translation factor, used to determine the position of the wavelet function on the discrete time axis. First, select a suitable wavelet basis function and the number of decomposition layers, perform wavelet decomposition on the original pressure data, decompose the data into sub-signals of different scales and frequencies, and through setting a threshold, perform threshold processing on the wavelet coefficients to remove the wavelet coefficients corresponding to the noise generated by vehicle vibration and electromagnetic interference factors. Finally, perform wavelet reconstruction on the processed wavelet coefficients to obtain the filtered pressure data; The specific method for identifying the dent damage on the traction pin surface is: determine the position and quantity of the dent damage through a preset pressure data missing identification algorithm based on threshold comparison, and the pressure data threshold wherein, is obtained by statistically averaging the pressure data collected from the traction pin under normal conditions under the same test conditions, representing the average level of the surface pressure of the traction pin under normal conditions, represents the standard deviation of the pressure data, reflecting the degree of dispersion of the pressure data relative to the mean value, represents the coefficient determined according to the false judgment rate requirement and the test reliability requirement, and is generally determined through multiple simulation experiments and actual test verifications; When the processed pressure data satisfies , it is determined that there is a dent damage at this position.

[0024] In the embodiment of the present invention, in S6, the method for quantifying the damage characteristics is: Calculate the damage density , , wherein, represents the number of dent damages on the outer surface of the traction pin, represents the outer surface area of the traction pin, represents the bottom radius of the traction pin, represents the length of the traction pin, perform grid division on the traction pin surface, and count the number of dent damages in each grid area , thereby calculating the damage density; The method for evaluating the safety level of the traction pin is: The safety level is evaluated based on a neural network model. The model adopts a multi-layer perceptron structure. The input layer receives the damage feature data obtained from data analysis, including the position, quantity, and density of dent damages. The model outputs the safety level. , where represents the activation function, which is used to introduce non-linear factors and enhance the expression ability of the model. represents the weight, which is updated through the backpropagation algorithm. represents the update amount of the weight. represents the input value of the -th neuron in the input layer, that is, a certain dimension of the damage feature data. represents the bias term, which is used to adjust the activation threshold of the neuron. represents the learning rate, which is determined according to the convergence speed and stability requirements of model training and controls the step size of each weight update. represents the loss function calculated through the cross-entropy loss function. , which is used to measure the difference between the model prediction value and the true label. represents the true label, that is, the safety level corresponding to the drawbar with a known safety state. represents the model prediction value. The model is trained with a large amount of drawbar data with known safety states and damage features to improve the accuracy and reliability of the model. Set the safety level determination standard: Let the safety level score , which is obtained by linearly transforming the safety level output by the model through the linear transformation function , that is , , where and are fitting coefficients, which are obtained through statistical analysis of a large number of drawbar samples with known safety levels. By performing linear regression analysis on the model output safety level of these samples and the corresponding actual safety level scores , the values of and are determined by minimizing the error between the actual score and the transformed score; When , it is determined that the drawbar is in a safe state; When , it is determined that the drawbar is in an unsafe state; , where is the safety level score threshold determined in advance through a large amount of experimental data and industry standards.

[0025] Example 2. As Figure 2As shown in the figure, a trailer towing test device includes a test saddle 1. An inner hole wall 2 is formed inside the test saddle 1. A towing pin 3 is detachably arranged inside the inner hole wall 2. A locking tongue 4 for locking and limiting the towing pin 3 is movably arranged inside the test saddle 1.

[0026] The embodiments disclosed in the present invention are preferred embodiments, but not limited thereto. Those of ordinary skill in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not depart from the spirit of the present invention, they are within the protection scope of the present invention.

Claims

1. A trailer towing test method, characterized in that: The following steps are involved: S1, preparation stage, remove the original traction saddle of the tractor to be tested, replace it with a test saddle, arrange mechanical sensors along the axis direction on the inner wall of the test saddle and the inner wall of the lock tongue, and connect the tractor test saddle with the trailer traction pin; S2, test condition setting, setting the uniform forward speed and uniform reverse speed conditions; S3, uniform speed traction condition test, the tractor is started and drives at the set uniform speed forward condition, and the pressure on the rear surface of the traction pin is detected by using the mechanical sensor arranged on the inner wall of the lock tongue. The tractor driver adjusts the driving angle according to the driving path so that the relative position of the traction pin and the mechanical sensor covers each detection area; S4, uniform speed reverse working condition test, the tractor is started and drives according to the set uniform speed reverse working condition, and the pressure on the front surface of the traction pin is detected by using the mechanical sensor arranged on the inner hole wall of the test saddle. The tractor driver adjusts the driving angle according to the driving path so that the relative position of the traction pin and the mechanical sensor covers each detection area; S5, data analysis, obtaining the pressure data collected in steps S3 and S4, filtering the collected data, and identifying dent damage on the traction pin surface; S6. Safety assessment, quantify damage characteristics, and assess the safety level of the traction pin.

2. A trailer towing test method according to claim 1, characterized in that: In S1, the mechanical sensor group on the inner hole wall of the test saddle and the inner wall of the lock tongue are arranged opposite to each other; When connecting the trailer and the tractor, use a gap measuring ruler with an accuracy of 0.1mm to check the gap at the connection to ensure that the gap value is In the standard range .

3. A trailer towing test method according to claim 2, characterized in that: In S3 and S4, the tractor driver adjusts the driving angle according to the driving path. Need to meet ,in, is the maximum angle of the tractor to swing to the left, In order to achieve the maximum right swing angle of the tractor, the driver slowly turns the steering wheel to change the driving trajectory of the tractor into a slight arc, thereby changing the relative position of the traction pin and the mechanical sensor, ensuring that each detection area divided along the axial direction of the traction pin surface is scanned by the mechanical sensor at least once.

4. A trailer towing test method according to claim 3, characterized in that: In S5, the data filtering processing method adopts the wavelet transform algorithm, and its transformation formula is: ； in, is the raw pressure signal, is the scale parameter, is the translation parameter, is the wavelet basis function; Discrete wavelet transform is a discretization of continuous wavelet transform in scale and translation. , its discrete wavelet transform is expressed as: ； in, , is the discretized wavelet basis function, is the normalization factor, is a discrete time sequence number, is the length of the sequence, is the discrete index of the scale factor, Discrete index of the translation factor that determines the position of the wavelet function on the discrete time axis.

5. A trailer towing test method according to claim 4, characterized in that: In said S5, the specific method for identifying the dent damage on the traction pin surface is: determining the dent damage location and quantity by using a preset pressure data missing recognition algorithm based on threshold comparison, and the pressure data threshold ,in, The average pressure value of the traction pin under normal conditions is obtained by statistically averaging the pressure data collected under the same test conditions. represents the standard deviation of the pressure data, It represents the coefficient determined according to the false positive rate requirement and the test reliability requirement; When the processed pressure data satisfy , it is determined that there is dent damage at that location.

6. A trailer towing test method according to claim 5, characterized in that: In S6, the method for quantifying the damage characteristics is: Calculating damage density , , ,in, Indicates the number of dent damages on the outer surface of the traction pin, represents the outer surface area of ​​the traction pin, It represents the bottom radius of the traction pin. Indicates the length of the traction pin; The safety level assessment method for traction pins is as follows: Safety level is assessed based on a neural network model. The model uses a multi-layer perceptron structure. The input layer receives damage feature data obtained through data analysis, including the location, number, and density of dent damage. The model outputs the safety level. ,in, represents the activation function, represents the weight, which is updated by the back-propagation algorithm. , represents the update amount of weight, The input layer The input value of a neuron, represents the bias term, represents the learning rate, represents the loss function calculated by the cross entropy loss function, , represents the true label, It represents the predicted value of the model. The model is trained through a large amount of traction pin data with known safety status and damage characteristics to improve the accuracy and reliability of the model.

7. A trailer towing test method according to claim 6, characterized in that: In S6, the security level determination criteria are set: the security level score is set , the safety level output by the model Linear transfer function Get, that is , ,in, and is the fitting coefficient, and the safety level is output by the model of these samples and the corresponding actual safety level score Linear regression analysis was performed to minimize the error between the actual score and the transformed score to determine and The value of when When the traction pin is in a safe state; when When the traction pin is in an unsafe state; in, The safety level score threshold is determined in advance based on a large amount of experimental data and industry standards.

8. A device applied to a trailer towing test method as claimed in claim 7, characterized in that: The invention comprises a test saddle, wherein an inner hole wall is formed inside the test saddle, a traction pin is detachably arranged inside the inner hole wall, and a locking tongue for locking and limiting the traction pin is movably arranged inside the test saddle.

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