Tracked vehicle soil adhesion coefficient evaluation method for highly saturated mud flat terrain

Abstract

The invention belongs to the technical field of tracked vehicle soil adhesion coefficient evaluation, and particularly relates to a tracked vehicle soil adhesion coefficient evaluation method for high-saturation mudflat terrains, which comprises the following steps: a tracked vehicle passes through a mudflat area, and the type and the moisture content range of the mudflat are identified by combining a mudflat state database and applying a classification algorithm; the sinking amount of the tracked vehicle is calculated; resistance parameters are calibrated on the basis of the sinking amount; and longitudinal resistance and transverse resistance models of the tidal flat of the tracked vehicle are constructed in combination with the structural size of the tracked vehicle. And evaluating longitudinal and transverse mud flat adhesion coefficients of the tracked vehicle by combining the weight of the whole vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of evaluating the soil adhesion coefficient of tracked vehicles, and particularly relates to a method for evaluating the soil adhesion coefficient of tracked vehicles for high-saturation tidal flat terrain. Background Art

[0002] Tracked amphibious vehicles are a type of multi-functional vehicle designed specifically for complex terrains, combining the mobility capabilities on land and water, making them perform excellently in various environments. Such vehicles are widely used in military, rescue, exploration and other fields, especially important in situations where it is necessary to cross water bodies and soft terrains. In military applications, tracked amphibious vehicles can quickly enter land directly from the sea or lakes, providing great strategic flexibility; in rescue missions, tracked amphibious vehicles can reach the disaster area through damaged roads or waters to transport rescue supplies and personnel in a timely manner; in engineering and exploration, tracked amphibious vehicles can undertake tasks such as transporting equipment and building materials, and can conduct geological exploration activities on water and land.

[0003] The tidal flat terrain that tracked amphibious vehicles inevitably face during the process of landing on land. The soil in the tidal flat is usually a mixture of sand, silt or clay. These soils have a high water content, resulting in a low soil density, high compressibility and relatively low bearing capacity. When the tracked vehicle is under heavy load, the soft tidal flat ground reduces the grip of the tracks and increases the risk of slipping. Summary of the Invention

[0004] (I) Technical Problems to be Solved

[0005] The technical problem to be solved by the present invention is: how to provide a method for evaluating the soil adhesion coefficient of tracked vehicles for high-saturation tidal flat terrain.

[0006] (II) Technical Solutions

[0007] To solve the above technical problems, the present invention provides a method for evaluating the soil adhesion coefficient of tracked vehicles for high-saturation tidal flat terrain, as Figure 1 shown. The method for evaluating the soil adhesion coefficient of tracked vehicles for high-saturation tidal flat terrain includes the following steps:

[0008] Step S1: Tidal flat state identification;

[0009] Step S2: Calibration of tidal flat settlement parameters;

[0010] Step S3: Construction of a pressure-settlement model for segmented tidal flat terrain;

[0011] Step S4: Prediction of tidal flat subsidence amount;

[0012] Step S5: Calibration of tidal flat resistance parameters of tracked vehicles;

[0013] Step S6: Construction of the beach soil resistance model for tracked vehicles;

[0014] Step S7: Evaluation of the tractive coefficient of tracked vehicles on the beach.

[0015] Among them, in the said Step S1, beach state identification is carried out;

[0016] Apply the classification learning algorithm ResNet-50 network (any algorithm with classification function can be implemented) to identify the type of the beach and the water content range of the soil;

[0017] The types of the beach are divided into frictional soils mainly with friction and cohesive soils mainly with cohesion, and the water content of the soil is divided into three water content levels: low, medium, and high.

[0018] Among them, as Figure 2 shown, the said Step S1 includes:

[0019] Step S11: Construction of the beach state database;

[0020] Step S12: Identification of the beach type;

[0021] Step S13: Identification of the beach water content range;

[0022] Step S14: Identification of the beach state.

[0023] Among them, in the said Step S11, the beach state database is constructed;

[0024] There are 6 labels for the beach state in the beach state database, namely frictional low water content soil, frictional medium water content soil, frictional high water content soil, cohesive low water content soil, cohesive medium water content soil, and cohesive high water content soil; the database is as Figure 3 shown;

[0025] In the said Step S12, the beach type is identified;

[0026] Apply the deep residual network ResNet-50 (any algorithm with classification function can be implemented), and identify and classify according to the color and texture characteristics of the beach to realize the identification of the beach type, and the output is frictional soil or cohesive soil. For example, the beach is frictional soil and the silt is cohesive soil;

[0027] In the said Step S13, the beach water content range is identified;

[0028] Apply the deep residual network ResNet-50 (any algorithm with classification function can be used) to identify the saturation state of the tidal flat. The moisture content of the tidal flat is divided into three levels: low, medium, and high. Among them, the recommended ranges of low, medium, and high moisture contents for the frictional soil corresponding to the sandy beach are 0% - 3%, 3% - 10%, and 10% - 25%; the recommended ranges of low, medium, and high moisture contents for the cohesive soil corresponding to the silt are 0 - 15%, 15% - 35%, and 35% - 60%.

[0029] In the step S14, identify the state of the tidal flat:

[0030] The input of the tidal flat state recognition process is the tidal flat photo collected in real time by the tracked vehicle, and the output is the tidal flat type and moisture content; as Figure 4 shown, after the tidal flat state recognition, judge the tidal flat type and moisture content of the tidal flat to be recognized.

[0031] Specifically, for example, construct a tidal flat state database. There are 6 labels for the tidal flat state in the database, namely frictional low moisture content soil, frictional medium moisture content soil, frictional high moisture content soil, cohesive low moisture content soil, cohesive medium moisture content soil, and cohesive high moisture content soil; apply the deep residual network ResNet-50 (any algorithm with classification function can be used), and identify and classify according to the characteristics such as the color and texture of the tidal flat to realize the recognition of the tidal flat type and moisture content. The input of the tidal flat state recognition process is the tidal flat photo collected in real time by the tracked vehicle, and the output is the tidal flat type and moisture content;

[0032] Among them, in the step S2, calibrate the tidal flat settlement parameters;

[0033] The soil settlement ability is related to the track structure size, the weight of the tracked vehicle, the soil type, and the moisture content. The settlement model is expressed as:

[0034]

[0035] In the formula: p is the ground contact pressure of the tracked vehicle; k c is the cohesive deformation modulus; k φ is the frictional deformation modulus; b is the track width; n is the settlement index; z is the settlement amount;

[0036] For the frictional soil corresponding to the sandy beach, the recommended values of the cohesive deformation modulus for low, medium, and high moisture contents are 3.7e-2 kPa / m n +1 、3.5e-2 kPa / m n+1 、3.4e-2 kPa / m n+1 , and the recommended value of the frictional deformation modulus is 1.4e-3 MPa / m n+2 、1.1e-3 MPa / m n+2 、0.8e-3 MPa / m n+2 The recommended values of the subsidence index are 0.4, 0.5, and 0.55;

[0037] For cohesive soils corresponding to clay, the recommended values of the cohesive deformation modulus for low, medium, and high water contents are 0.41 MPa / m n+1 、3.17 MPa / m n+1 、0.1 MPa / m n+1 The recommended value of the frictional deformation modulus is 2.1e-2 MPa / m n+2 、43e-2 MPa / m n+2 、0.5e-2 MPa / m n+2 The recommended values of the subsidence index are 0.5, 0.8, and 1.1;

[0038] The above recommended values are calibrated according to the recognition results of the tidal flat state.

[0039] Among them, in step S3, a sectional pressure-subsidence model of the tidal flat terrain is constructed;

[0040] During the pressure-subsidence process of the highly saturated tidal flat, there is a stratification phenomenon, which is divided into upper and lower loose and dense layers. The upper layer of soil is more prone to deformation; the water content of the loose layer of soil is higher, and the pore water content between soil particles is greater than that of the dense layer, directly resulting in a smaller liquid bridge force between particles. Macroscopically, the mechanical properties of the upper layer of soil are less than those of the lower layer of soil. A sectional pressure-subsidence model is required to more accurately characterize the subsidence process of the tracked vehicle:

[0041]

[0042] In the formula: k cl 、k cd are the cohesive deformation moduli of the loose layer and the dense layer; k φl 、k φd are the frictional deformation moduli of the loose layer and the dense layer; n l 、n d are the subsidence indices of the loose layer and the dense layer; in actual calculations, the water content of the lower layer of soil is one level lower than that of the upper layer of soil; if the recognition result of the tidal flat water content is high, the parameters of the upper tidal flat are assigned according to the high water content, and the lower tidal flat is calculated according to the medium water content assignment.

[0043] Among them, in step S4, the prediction of the tidal flat subsidence amount is carried out;

[0044] During the driving process of the tracked vehicle on the highly saturated tidal flat, the bearing characteristics of the tidal flat are random within a certain range. Therefore, the subsidence of the vehicle on the highly saturated tidal flat should be within a range. According to the sectional pressure-subsidence model of the tidal flat terrain, the subsidence range of the tracked vehicle during driving on the tidal flat is deduced:

[0045]

[0046] That is

[0047]

[0048] In the formula: L is the track length; W is the vehicle weight, z min and z max are the upper and lower extreme values of the settlement range.

[0049] Among them, in the step S5, the calibration of the beach resistance parameters of the tracked vehicle is carried out;

[0050] Before calculating the beach resistance of the tracked vehicle, it is necessary to complete the calibration of the beach bearing capacity coefficient. Since the track is not completely smooth and there is a considerable amount of friction between the track and the surface of the foundation soil, the foundation ultimate bearing capacity is applied to calculate the beach bearing capacity coefficient:

[0051] Kc = (Nc - tanφ)cos 2 φ

[0052]

[0053] In the formula: φ is the soil internal friction angle;

[0054] K c 、K r are the cohesion of the beach, the influence of the soil weight on the passive soil, and are dimensionless parameters;

[0055] Among them, the N of low, medium, and high moisture content frictional soils r takes values of 45.2, 21.6, 10.7, N c takes values of 57.4, 36.9, 24.7;

[0056] The N of low, medium, and high moisture content cohesive soils r takes values of 1.8, 0.5, 0, N c takes values of 9.6, 7.3, 5.7;

[0057] The above recommended values are calibrated according to the beach state recognition results.

[0058] Among them, in the step S6, the construction of the beach soil resistance model of the tracked vehicle is carried out;

[0059] The beach belongs to soft soil with large settlement. During the driving process of the tracked vehicle, a large amount of accumulated soil is generated around the track, and the soil pushing resistance will account for the vast majority of the vehicle's traveling resistance. According to the passive earth theory, the longitudinal resistance formula and transverse resistance formula of the soil of the tracked vehicle are obtained by integrating the track width and length:

[0060]

[0061] Where: F r is the longitudinal soil resistance of the tracked vehicle; F l is the lateral soil resistance of the tracked vehicle; c is the soil cohesion; ρ is the soil density;

[0062] For frictional soil, the recommended values of soil cohesion c for low, medium, and high moisture contents are 3.3 kPa, 3.1 kPa, and 2.8 kPa respectively, and the recommended values of soil internal friction angle φ are 34°, 30°, and 28° respectively;

[0063] For cohesive soil, the recommended values of soil cohesion c for low, medium, and high moisture contents are 8 kPa, 15 kPa, and 5 kPa respectively, and the recommended values of soil internal friction angle φ are 8°, 10°, and 3° respectively;

[0064] Among them, for low, medium, and high moisture content frictional soil, the N r values are 45.2, 21.6, and 10.7, and the N c values are 57.4, 36.9, and 24.7;

[0065] For low, medium, and high moisture content cohesive soil, the N r values are 1.8, 0.5, and 0, and the N c values are 9.6, 7.3, and 5.7;

[0066] The above recommended values are calibrated according to the recognition results of the tidal flat state.

[0067] Among them, in the step S7, the evaluation of the tractive coefficient of the tracked vehicle on the tidal flat is carried out;

[0068] Combined with the extreme values z min and z max of the subsidence amount of the tracked vehicle, substitute them into the longitudinal resistance formula and lateral resistance formula for the tracked vehicle to travel on the tidal flat, and combined with the weight of the tracked vehicle, complete the evaluation of the soil tractive coefficient of the tracked vehicle:

[0069] μ r =[F rmin ,F rmax

[0070] μ l =[F lmin ,F lmax

[0071] Where: μ r is the longitudinal soil resistance coefficient of the tracked vehicle; μ l is the lateral soil resistance coefficient of the tracked vehicle; F rmin and F rmax are the extreme values of the longitudinal soil resistance of the tracked vehicle respectively; F lmin and F lmax ​​They are the extreme values of the lateral soil resistance of the tracked vehicle respectively.

[0072] (III) Beneficial Effects

[0073] Compared with the prior art, the present invention helps to reduce the risk of the vehicle getting stuck in the tidal flat terrain by accurately evaluating the resistance coefficient of the tracked vehicle on the tidal flat terrain. At the same time, through the accurate evaluation of the resistance coefficient, the present invention can be used to guide the operation strategy of the vehicle, such as selecting the best travel route and speed, so as to avoid unnecessary energy loss. By analyzing the resistance coefficients under different working conditions, the present invention can better understand the interaction mechanism between the vehicle and the soil, and then develop more efficient and reliable amphibious or tracked vehicles to ensure their stability and reliability in various harsh environments.

[0074] In summary, the present invention provides a method for evaluating the soil adhesion coefficient of a tracked vehicle for high-saturation tidal flat terrain, which solves the problems of evaluating the tidal flat soil state, identifying the soil type and moisture content, predicting the settlement amount of the vehicle, and quickly evaluating the driving resistance range of the tracked vehicle during the landing process of the amphibious tracked vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 is a flowchart of the method for evaluating the soil adhesion coefficient of a tracked vehicle for high-saturation tidal flat terrain provided by an embodiment of the present invention;

[0076] Figure 2 is a flowchart of the tidal flat state identification provided by an embodiment of the present invention;

[0077] Figure 3 is a tidal flat state identification database provided by an embodiment of the present invention;

[0078] Figure 4 is a schematic diagram of the tidal flat state identification result provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0079] To make the objectives, contents, and advantages of the present invention clearer, the following further describes in detail the specific embodiments of the present invention with reference to the drawings and embodiments.

[0080] To solve the above technical problems, the present invention provides a method for evaluating the soil adhesion coefficient of a tracked vehicle for high-saturation tidal flat terrain, as Figure 1 shown, the method for evaluating the soil adhesion coefficient of a tracked vehicle for high-saturation tidal flat terrain includes the following steps:

[0081] Step S1: Tidal flat state identification;

[0082] Step S2: Calibration of tidal flat settlement parameters;

[0083] Step S3: Construction of the sectional pressure-settlement model for the tidal flat terrain;

[0084] Step S4: Prediction of the subsidence amount of the tidal flat;

[0085] Step S5: Calibration of the tidal flat resistance parameters of the tracked vehicle;

[0086] Step S6: Construction of the tidal flat soil resistance model for the tracked vehicle;

[0087] Step S7: Evaluation of the tidal flat adhesion coefficient of the tracked vehicle.

[0088] Among them, in the said Step S1, the tidal flat state is identified;

[0089] The classification learning algorithm ResNet-50 network (any algorithm with classification function can be used) is applied to identify the type of the tidal flat and the water content range of the soil;

[0090] The types of the tidal flat are divided into frictional soil mainly with friction and cohesive soil mainly with cohesion, and the water content of the soil is divided into three water content levels: low, medium, and high.

[0091] Among them, as Figure 2 shown, the said Step S1 includes:

[0092] Step S11: Construction of the tidal flat state database;

[0093] Step S12: Identification of the tidal flat type;

[0094] Step S13: Identification of the tidal flat water content range;

[0095] Step S14: Identification of the tidal flat state.

[0096] Among them, in the said Step S11, the tidal flat state database is constructed;

[0097] There are 6 labels for the tidal flat state in the tidal flat state database, which are respectively frictional low water content soil, frictional medium water content soil, frictional high water content soil, cohesive low water content soil, cohesive medium water content soil, and cohesive high water content soil; the database is as Figure 3 shown;

[0098] In the said Step S12, the tidal flat type is identified;

[0099] The deep residual network ResNet-50 (any algorithm with classification function can be used) is applied to identify and classify according to the color and texture characteristics of the tidal flat, realizing the identification of the type of the tidal flat, and the output is frictional soil or cohesive soil, such as sandy beach is frictional soil and silt is cohesive soil;

[0100] In the said Step S13, the tidal flat water content range is identified;

[0101] Apply the deep residual network ResNet-50 (any algorithm with classification function can be used) to identify the saturation state of the tidal flat. The water content of the tidal flat is divided into three levels: low, medium, and high. Among them, the recommended ranges of low, medium, and high water contents for the frictional soil corresponding to the sandy beach are 0% - 3%, 3% - 10%, and 10% - 25%; the recommended ranges of low, medium, and high water contents for the cohesive soil corresponding to the silt are 0 - 15%, 15% - 35%, and 35% - 60%.

[0102] In step S14, identify the tidal flat state:

[0103] The input of the tidal flat state recognition process is the tidal flat photo collected in real time by the tracked vehicle, and the output is the tidal flat type and water content; as Figure 4 shown, after the tidal flat state is recognized, judge the tidal flat type and water content of the tidal flat to be recognized.

[0104] Specifically, for example, construct a tidal flat state database. There are 6 labels for the tidal flat state in the database, namely frictional low water content soil, frictional medium water content soil, frictional high water content soil, cohesive low water content soil, cohesive medium water content soil, and cohesive high water content soil; apply the deep residual network ResNet-50 (any algorithm with classification function can be used), and identify and classify according to the characteristics such as the color and texture of the tidal flat to realize the recognition of the type and water content of the tidal flat. The input of the tidal flat state recognition process is the tidal flat photo collected in real time by the tracked vehicle, and the output is the tidal flat type and water content;

[0105] Among them, in step S2, calibrate the tidal flat subsidence parameters;

[0106] The soil subsidence ability is related to the track structure size, the weight of the tracked vehicle, the soil type, and the water content. The subsidence model is expressed as:

[0107]

[0108] In the formula: p is the ground contact pressure of the tracked vehicle; k c is the cohesive deformation modulus; k φ is the frictional deformation modulus; b is the track width; n is the subsidence index; z is the subsidence amount;

[0109] For the frictional soil corresponding to the sandy beach, the recommended values of the cohesive deformation modulus for low, medium, and high water contents are 3.7e-2 kPa / m n +1 、3.5e-2 kPa / m n+1 、3.4e-2 kPa / m n+1 , and the recommended value of the frictional deformation modulus is 1.4e-3 MPa / m n+2, 1.1e-3 MPa / m n +2 , 0.8e-3 MPa / m n+2 , the recommended values of the settlement index are 0.4, 0.5, and 0.55;

[0110] For cohesive soils corresponding to clay, the recommended values of the cohesive deformation modulus for low, medium, and high water contents are 0.41 MPa / m n+1 , 3.17 MPa / m n+1 , 0.1 MPa / m n+1 , the recommended value of the frictional deformation modulus is 2.1e-2 MPa / m n+2 , 43e-2 MPa / m n+2 , 0.5e-2 MPa / m n+2 , the recommended values of the settlement index are 0.5, 0.8, and 1.1;

[0111] The above recommended values are calibrated according to the recognition results of the tidal flat state.

[0112] Among them, in the step S3, a sectional pressure-settlement model of the tidal flat terrain is constructed;

[0113] During the pressure-settlement process of the highly saturated tidal flat, there is a layering phenomenon, which is divided into upper and lower loose and dense layers. The upper layer of soil is more prone to deformation; the water content of the loose layer of soil is higher, and the pore water content between soil particles is greater than that of the dense layer, directly resulting in a smaller liquid bridge force between particles. Macroscopically, the mechanical properties of the upper layer of soil are less than those of the lower layer of soil. A sectional pressure-settlement model is required to more accurately characterize the settlement process of the tracked vehicle:

[0114]

[0115] In the formula: k cl , k cd are the cohesive deformation moduli of the loose layer and the dense layer; k φl , k φd are the frictional deformation moduli of the loose layer and the dense layer; n l , n d are the settlement indices of the loose layer and the dense layer; in actual calculations, the water content of the lower layer of soil is one level lower than that of the upper layer of soil; if the recognition result of the tidal flat water content is high, the parameters of the upper tidal flat are assigned according to the high water content, and the lower tidal flat is calculated according to the medium water content assignment.

[0116] Among them, in the step S4, the prediction of the tidal flat subsidence amount is carried out;

[0117] During the driving process of a tracked vehicle on a highly saturated tidal flat, the bearing characteristics of the tidal flat are random within a certain range. Therefore, the settlement of the vehicle on the highly saturated tidal flat should be within a range. According to the sectional pressure-settlement model of the tidal flat terrain, the settlement range of the tracked vehicle during driving on the tidal flat is derived:

[0118]

[0119] That is

[0120]

[0121] In the formula: L is the length of the track; W is the total vehicle weight, z min and z max are the upper and lower extreme values of the settlement range.

[0122] Among them, in the step S5, the calibration of the tidal flat resistance parameters of the tracked vehicle is carried out;

[0123] Before calculating the tidal flat resistance of the tracked vehicle, the calibration of the tidal flat bearing capacity coefficient needs to be completed. Since the track is not completely smooth and there is a considerable frictional force between the track and the surface of the foundation soil, the foundation ultimate bearing capacity is applied to calculate the tidal flat bearing capacity coefficient:

[0124] Kc = (Nc - tanφ)cos 2 φ

[0125]

[0126] In the formula: φ is the soil internal friction angle;

[0127] K c 、K r are the cohesion of the tidal flat and the influence of the soil weight on the passive soil, which are dimensionless parameters;

[0128] Among them, the N r values of low, medium, and high moisture content frictional soils are 45.2, 21.6, and 10.7, and the N c values are 57.4, 36.9, and 24.7;

[0129] The N r values of low, medium, and high moisture content cohesive soils are 1.8, 0.5, and 0, and the N c values are 9.6, 7.3, and 5.7;

[0130] The above recommended values are calibrated according to the recognition results of the tidal flat state.

[0131] Among them, in the step S6, the construction of the tidal flat soil resistance model of the tracked vehicle is carried out;

[0132] Tidal flats belong to soft soil with relatively large subsidence. During the driving process of tracked vehicles, a large amount of soil accumulates around the tracks, and the pushing resistance will account for the vast majority of the vehicle's driving resistance. According to the passive earth theory, by integrating the track width and length, the longitudinal soil resistance formula and transverse resistance formula of tracked vehicles are obtained:

[0133]

[0134] In the formula: F r is the longitudinal soil resistance of the tracked vehicle; F l is the transverse soil resistance of the tracked vehicle; c is the soil cohesion; ρ is the soil density;

[0135] For frictional soil, the recommended values of soil cohesion c for low, medium, and high water contents are 3.3 kPa, 3.1 kPa, and 2.8 kPa respectively, and the recommended values of soil internal friction angle φ are 34°, 30°, and 28° respectively;

[0136] For cohesive soil, the recommended values of soil cohesion c for low, medium, and high water contents are 8 kPa, 15 kPa, and 5 kPa respectively, and the recommended values of soil internal friction angle φ are 8°, 10°, and 3° respectively;

[0137] Among them, for low, medium, and high water content frictional soil, the N r values are 45.2, 21.6, and 10.7, and the N c values are 57.4, 36.9, and 24.7;

[0138] For low, medium, and high water content cohesive soil, the N r values are 1.8, 0.5, and 0, and the N c values are 9.6, 7.3, and 5.7;

[0139] The above recommended values are calibrated according to the recognition results of the tidal flat state.

[0140] Among them, in step S7, the evaluation of the tractive coefficient of the tracked vehicle on the tidal flat is carried out;

[0141] Combined with the extreme values z min 、z max of the subsidence of the tracked vehicle, substitute them into the longitudinal resistance formula and transverse resistance formula of the tracked vehicle driving on the tidal flat, and combined with the weight of the tracked vehicle, complete the evaluation of the soil tractive coefficient of the tracked vehicle:

[0142] μ r =[F rmin ,F rmax

[0143] μ l =[F lmin ,F lmax

[0144] ​​Where: μ r is the longitudinal soil resistance coefficient of the tracked vehicle; μ l is the lateral soil resistance coefficient of the tracked vehicle; F rmin and F rmax are the extreme values of the longitudinal soil resistance of the tracked vehicle respectively; F lmin and F lmax are the extreme values of the lateral soil resistance of the tracked vehicle respectively.

[0145] In summary, the present invention belongs to the technical field of evaluating the soil adhesion coefficient of tracked vehicles, and specifically relates to a method for evaluating the soil adhesion coefficient of tracked vehicles for high-saturation tidal flat terrain. The method includes that the tracked vehicle passes through the tidal flat area, combines the tidal flat state database, applies a classification algorithm to identify the type and moisture content range of the tidal flat, predicts the settlement parameters of the tidal flat, establishes a segmented pressure-settlement model of the soft tidal flat for the tracked vehicle, calculates the subsidence amount of the tracked vehicle, calibrates the resistance parameters based on the subsidence amount, combines the track structure dimensions, constructs the longitudinal and lateral resistance models of the tracked vehicle on the tidal flat, and evaluates the longitudinal and lateral tidal flat adhesion coefficients of the tracked vehicle in combination with the vehicle weight.

[0146] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain, characterized in that The method for evaluating the soil adhesion coefficient of a crawler vehicle facing a highly saturated tidal flat terrain includes the following steps: Step S1: Tidal flat state identification; Step S2: Calibration of tidal flat settlement parameters; Step S3: Construction of a sectional pressure-settlement model for the tidal flat terrain; Step S4: Prediction of the subsidence amount of the tidal flat; Step S5: Calibration of the tidal flat resistance parameters of the crawler vehicle; Step S6: Construction of a tidal flat soil resistance model for the crawler vehicle; Step S7: Evaluation of the tidal flat adhesion coefficient of the crawler vehicle.

2. The method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain according to claim 1, wherein In the said Step S1, tidal flat state identification is carried out; A classification learning algorithm is applied to identify the type of the tidal flat and the range of soil moisture content; The types of the tidal flat are divided into frictional soil mainly with friction and cohesive soil mainly with cohesion, and the soil moisture content is divided into three levels: low, medium, and high.

3. The method for evaluating the soil adhesion coefficient of a crawler vehicle for a highly saturated tidal flat terrain according to claim 2, wherein As shown in Figure 2, the said Step S1 includes: Step S11: Construction of a tidal flat state database; Step S12: Identification of the tidal flat type; Step S13: Identification of the range of tidal flat moisture content; Step S14: Tidal flat state identification.

4. The method for evaluating the soil adhesion coefficient of a crawler vehicle for a highly saturated tidal flat terrain according to claim 3, wherein, In the said Step S11, a tidal flat state database is constructed; There are 6 labels for the tidal flat state in the tidal flat state database, namely frictional low moisture content soil, frictional medium moisture content soil, frictional high moisture content soil, cohesive low moisture content soil, cohesive medium moisture content soil, and cohesive high moisture content soil; In the said Step S12, the tidal flat type is identified; The deep residual network ResNet-50 is applied to identify and classify according to the color and texture characteristics of the tidal flat, realizing the identification of the type of the tidal flat, and the output is frictional soil or cohesive soil; In the said Step S13, the range of tidal flat moisture content is identified; The deep residual network ResNet-50 is applied to identify the saturation state of the tidal flat, and the tidal flat moisture content is divided into three levels: low, medium, and high; In the said Step S14, tidal flat state identification is carried out: The input of the tidal flat state identification process is the tidal flat photo collected by the crawler vehicle in real time, and the output is the tidal flat type and moisture content; after the tidal flat state identification, the tidal flat type and moisture content of the tidal flat to be identified are judged.

5. The method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain according to claim 2, wherein, In the said Step S2, calibration of tidal flat settlement parameters is carried out; The soil settlement ability is related to the track structure size, the weight of the crawler vehicle, the soil type, and the moisture content. The settlement model is expressed as: Where: p is the ground contact pressure of the tracked vehicle; k c is the cohesive deformation modulus; k φ is the frictional deformation modulus; b is the track width; n is the settlement index; z is the settlement amount; For the frictional soil corresponding to the beach, the recommended values of the cohesive deformation modulus for low, medium, and high water contents are 3.7e-2 kPa / m n+1 , 3.5e-2 kPa / m n+1 , 3.4e-2 kPa / m n+1 , and the recommended value of the frictional deformation modulus is 1.4e-3 MPa / m n+2 , 1.1e-3 MPa / m n+2 , 0.8e-3 MPa / m n+2 , and the recommended values of the settlement index are 0.4, 0.5, and 0.55; For cohesive soil corresponding to clay, the recommended values of cohesive deformation modulus for low, medium and high water contents are 0.41 MPa / m n+1 , 3.17 MPa / m n+1 , 0.1 MPa / m n+1 , and the recommended value of frictional deformation modulus is 2.1e-2 MPa / m n+2 , 43e-2 MPa / m n+2 , 0.5e-2 MPa / m n+2 , and the recommended values of settlement index are 0.5, 0.8, 1.1; The above recommended values are calibrated according to the tidal flat state identification results.

6. The method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain according to claim 5, characterized in that In the said Step S3, construction of a sectional pressure-settlement model for the tidal flat terrain is carried out; There is a layering phenomenon in the pressure-settlement process of the highly saturated tidal flat, which is divided into upper and lower loose and dense layers. The upper layer of soil is more prone to deformation; the water content of the loose layer of soil is higher, and the pore water content between soil particles is greater than that of the dense layer, directly resulting in a smaller liquid bridge force between particles. Macroscopically, the mechanical properties of the upper layer of soil are less than those of the lower layer of soil. A sectional pressure-settlement model is required to more accurately characterize the settlement process of the crawler vehicle: Where: k cl , k cd are the cohesive deformation moduli of the loose layer and the dense layer; k φl , k φd are the frictional deformation moduli of the loose layer and the dense layer; n l , n d are the settlement indices of the loose layer and the dense layer; in actual calculations, the water content of the lower soil layer is one level lower than that of the upper soil layer; if the recognition result of the water content of the tidal flat is high, the parameters of the upper tidal flat are assigned according to the high water content, and the lower tidal flat is calculated according to the medium water content assignment.

7. The method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain according to claim 6, wherein In the said Step S4, prediction of the subsidence amount of the tidal flat is carried out; During the driving process of the crawler vehicle on the highly saturated tidal flat, the bearing characteristics of the tidal flat are random within a certain range. Therefore, the subsidence of the vehicle on the highly saturated tidal flat should be a range. According to the sectional pressure-settlement model of the tidal flat terrain, the subsidence range of the crawler vehicle during driving on the tidal flat is deduced: That is Where: L is the crawler length; W is the vehicle weight, z min and z max are the upper and lower extreme values of the subsidence range.

8. The method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain according to claim 7, characterized in that In the step S5, the calibration of the beach resistance parameters of the tracked vehicle is carried out; Before calculating the beach resistance of the tracked vehicle, the calibration of the beach bearing capacity coefficient needs to be completed. Since the track is not completely smooth and there is a considerable amount of friction between the track and the surface of the foundation soil, the foundation ultimate bearing capacity is applied to calculate the beach bearing capacity coefficient: Kc = (Nc - tanφ)cos 2 φ In the formula: φ is the soil internal friction angle; K c and K r are the influence of cohesive force of tidal flat and soil weight on passive soil, and are dimensionless parameters; Among them, the N values of low, medium, and high moisture content frictional soils r are 45.2, 21.6, and 10.7, and the N c values are 57.4, 36.9, and 24.7; N values for cohesive soils with low, medium and high water contents r The N values are 1.8, 0.5, 0 c and the N values are 9.6, 7.3, 5.7; The above recommended values are calibrated according to the beach state recognition results.

9. The method for evaluating the soil adhesion coefficient of a crawler vehicle for high-saturation tidal flat terrain according to claim 8, wherein In the step S6, the construction of the beach soil resistance model of the tracked vehicle is carried out; The beach belongs to soft soil with large settlement. During the driving process of the tracked vehicle, a large amount of soil accumulates around the track, and the soil pushing resistance will account for the vast majority of the vehicle's traveling resistance. According to the passive earth theory, the longitudinal and lateral soil resistance formulas of the tracked vehicle are obtained by integrating the track width and length: In the formula: F r is the longitudinal soil resistance of the tracked vehicle; F l is the lateral soil resistance of the tracked vehicle; c is the soil cohesion; ρ is the soil density; The recommended values of the soil cohesion c for low, medium, and high moisture contents of frictional soil are 3.3 kPa, 3.1 kPa, and 2.8 kPa respectively, and the recommended values of the soil internal friction angle φ are 34°, 30°, and 28° respectively; The recommended values of the soil cohesion c for low, medium, and high moisture contents of cohesive soil are 8 kPa, 15 kPa, and 5 kPa respectively, and the recommended values of the soil internal friction angle φ are 8°, 10°, and 3° respectively; Among them, the N values of low, medium, and high moisture content frictional soils r are 45.2, 21.6, and 10.7, and the N c values are 57.4, 36.9, and 24.7; N values for cohesive soils with low, medium, and high moisture contents r take values of 1.8, 0.5, 0, and N c take values of 9.6, 7.3, 5.7; The above recommended values are calibrated according to the beach state recognition results.

10. The method for evaluating the soil adhesion coefficient of a crawler vehicle for a highly saturated tidal flat terrain according to claim 9, wherein, In the step S7, the evaluation of the beach adhesion coefficient of the tracked vehicle is carried out; Combined with the extreme value z of the subsidence amount of the tracked vehicle min 、z max Substitute into the longitudinal resistance formula and lateral resistance formula for the tracked vehicle to travel on the mudflat, and combined with the weight of the tracked vehicle, complete the evaluation of the soil adhesion coefficient of the tracked vehicle: μ r = [F rmin , F rmax ​ μ l = [F lmin , F lmax ​ where: μ r is the longitudinal soil resistance coefficient of the tracked vehicle; μ l is the lateral soil resistance coefficient of the tracked vehicle; F rmin and F rmax are the extreme values of the longitudinal soil resistance of the tracked vehicle respectively; F lmin and F lmax are the extreme values of the lateral soil resistance of the tracked vehicle respectively.

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