A method for sensitivity analysis of load parameters of light electric vehicles

Abstract

The present invention belongs to the field of active safety control of electric vehicles, and specifically relates to a method for analyzing the sensitivity of load parameters of light electric vehicles. When passengers or cargo are loaded, the load parameters of light electric vehicles and the position of the center of mass and geometric parameters of the vehicle change. Through the nonlinear dynamic equation model of load parameter sensitivity analysis; the dynamic system state equation of sensitivity analysis is obtained, the trajectory sensitivity of the load parameter is defined, and a quantitative analysis method for the sensitivity of the load parameters of light electric vehicles is established; by calculating the average value of the absolute value of the trajectory sensitivity and comparing its size for quantitative analysis, the sensitivity-related conclusions of the load parameters of light electric vehicles are obtained. The present invention develops a nonlinear dynamic model for sensitivity analysis of load parameters of light electric vehicles, establishes a quantitative analysis method for the sensitivity of load parameters of light electric vehicles, provides relevant theoretical basis for active safety control of light electric vehicles, and is conducive to improving the active safety of electric vehicles.

Description

Technical Field

[0001] The invention belongs to the field of active safety control of electric vehicles, and in particular relates to a load parameter sensitivity analysis method for light electric vehicles. Background Art

[0002] Traditional fuel-powered vehicles emit a large amount of harmful exhaust gas during driving, which has an increasingly serious impact on global climate change. At the same time, due to their heavy dependence on non-renewable resources such as oil, they have also brought huge challenges to the global energy supply. In the face of environmental and energy problems caused by traditional fuel-powered vehicles, the development of new energy vehicles has become a new trend, and pure electric vehicles that are directly powered by batteries and are safer, cleaner and more energy-efficient are their main development direction.

[0003] Considering that light electric vehicles have a broad market space in my country, compared with traditional vehicles, due to the significant reduction in vehicle mass and body size, light electric vehicles bring energy saving, but also make the driving safety of the vehicle relatively fragile. In particular, the change of load parameters (passenger or cargo load) will affect the handling characteristics and trajectory tracking performance of light electric vehicles, and thus make the dynamic characteristics of light electric vehicles more sensitive to the uncertainty and change of load parameters. However. In the current research on active safety control of electric vehicles, the sensitivity analysis of load parameters of light electric vehicles is less explored. Therefore, quantitative analysis of the sensitivity of load parameters of light electric vehicles can provide relevant theoretical support for active safety control of electric vehicles, which is particularly important. Summary of the invention

[0004] In view of the above problems, the present invention provides a light electric vehicle load parameter sensitivity analysis method.

[0005] The present invention adopts the following technical solution:

[0006] The light electric vehicle load parameter sensitivity analysis method of the present invention comprises the following analysis steps:

[0007] S1. Establish a nonlinear dynamic equation model for load parameter sensitivity analysis of light electric vehicles;

[0008] According to the dynamic characteristics of longitudinal motion, lateral motion, yaw and roll motion in the light electric vehicle system, a nonlinear dynamic equation model for load parameter sensitivity analysis of light electric vehicles is established through the changes in load parameters and vehicle center of mass position when the light electric vehicle is loaded with passengers or cargo;

[0009] S2, performing trajectory sensitivity analysis on the nonlinear dynamic equation model of the light electric vehicle with sensitive load parameters established in step S1;

[0010] By obtaining the dynamic system state equation of light electric vehicle load parameter sensitivity analysis, the trajectory sensitivity of light electric vehicle load parameters is defined, the median method is used to improve the calculation accuracy of trajectory sensitivity, and the sensitivity analysis method of light electric vehicle load parameters is established;

[0011] S3. Through quantitative analysis of the sensitivity of light electric vehicle load parameters, the average value of the absolute value of trajectory sensitivity is defined, and quantitative analysis is performed by calculating the average value of the absolute value of trajectory sensitivity and comparing its size to obtain the quantitative analysis conclusion of the sensitivity of light electric vehicle load parameters.

[0012] In the light electric vehicle load parameter sensitivity analysis method of the present invention, the steps of establishing a light electric vehicle load parameter sensitivity analysis nonlinear dynamic model in step S1 are as follows:

[0013] The initial longitudinal motion of the vehicle without passengers or cargo is expressed as:

[0014]

[0015]

[0016] Lateral motion expression:

[0017]

[0018]

[0019] The yaw and roll motion expressions are:

[0020]

[0021]

[0022] When a light electric vehicle is loaded with passengers or cargo, the yaw moment of inertia and the center of mass of the vehicle will change.

[0023] The center of mass of the loaded mass is located relative to the coordinate vector of the original coordinate system: r = (x p ,y p ,z p ); where x p ,y p 、z p are the longitudinal, lateral and vertical coordinates of the load relative to the vehicle coordinate system, respectively;

[0024] Load m p The total mass of the loaded vehicle is: m n =m s +m p ;

[0025] The velocity V at the new center of mass can be calculated from the velocity V at the original center of mass 0 It is expressed by the following formula:

[0026] V=V 0 +r×r n

[0027] That is, the equation at the original center of mass is expressed as:

[0028]

[0029] The equation for the rotational motion of the body of a light vehicle is defined as:

[0030]

[0031] In the above formula, V and V 0 They represent the longitudinal, lateral and vertical velocity vectors of the vehicle when loaded and unloaded, respectively, and V = [V x ,V y ,V z ] T ,

[0032] r. represents the vehicle roll, pitch and yaw angular velocity vectors and their antisymmetric matrices, and

[0033] M represents the external torque, and M=[M x ,M y ,M z ] T ;x n ,y n 、z n Respectively represent the longitudinal, lateral and vertical coordinates of the center of mass of the vehicle after loading (m), and r n =[x n ,y n ,z n ] T ;

[0034] The new center of mass position coordinates in the original coordinate system are obtained by the above formula:

[0035]

[0036] At the same time, when a light vehicle is loaded with passengers or cargo, its related geometric parameters also change accordingly:

[0037]

[0038] In the above formula, m n、m p Respectively represent the vehicle mass and loaded mass (kg);

[0039] l f , l r Respectively represent the horizontal distance from the center of mass to the front and rear axles of the vehicle after loading (m);

[0040] b l 、b r Respectively represent the horizontal distance from the center of mass to the center of the left and right wheels after loading (m);

[0041] I x ,I z ,I xz They represent the roll moment of inertia of the vehicle around the x-axis, the yaw moment of inertia around the z-axis, and the product of inertia of the vehicle's roll and yaw motions after loading (kgm 2 );

[0042] h n Indicates the distance of the roll axis from the ground after loading (m);

[0043] By using the above new center of mass position and the geometric parameter variables after loading passengers or cargo, the corresponding moment of inertia of the light vehicle dynamics model is expressed by the following formula:

[0044]

[0045] The light electric vehicle load parameter sensitivity analysis method of the present invention is based on the dynamic system state equation of the light electric vehicle load parameter sensitivity analysis in step S2 as follows:

[0046]

[0047] In the formula, x s represents the system state vector; represents the system parameter vector; u represents the system input; t represents the time variable; x s (0) represents the value of the system state vector at the initial moment;

[0048] In the above dynamic system state equation,

[0049]

[0050] θ p =[m p x p y p z p ] T

[0051] For the state equation of the light electric vehicle dynamic system, the trajectory sensitivity of the light electric vehicle load parameters is defined as:

[0052]

[0053]

[0054] In the above formula, represents the trajectory sensitivity of the i-th system state variable to the j-th parameter; k represents the system time sampling point;

[0055] For the relatively complex state equation system of the dynamic system of light electric vehicles, the numerical method is used to calculate the trajectory sensitivity to reduce the difficulty of calculation, and the median method is further used to improve the calculation accuracy of the trajectory sensitivity as follows:

[0056]

[0057] In the above formula, Indicates the rated value of the system parameter; Indicates the state variable value of the system when the parameter is the rated value;

[0058] The trajectory sensitivity is calculated based on a single factor disturbance as follows, where the longitudinal velocity V is defined as x For each parameter θ p The trajectory sensitivity is:

[0059]

[0060]

[0061]

[0062]

[0063] In the above formula, m p ′、x p ′、y p ′、z p ′ respectively represents the values ​​of the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position after the rated values ​​are perturbed; They represent the trajectory sensitivity of the vehicle longitudinal velocity to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively;

[0064] Define the center of mass sideslip angle β for each parameter θ p Track sensitivity:

[0065]

[0066]

[0067]

[0068]

[0069] In the above formula, They represent the trajectory sensitivity of the vehicle center of mass sideslip angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0070] Define the roll angular velocity r x For each parameter θ p Track sensitivity:

[0071]

[0072]

[0073]

[0074]

[0075] In the above formula, They represent the trajectory sensitivity of the vehicle roll angular velocity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0076] Define the yaw rate r z For each parameter θ p Track sensitivity:

[0077]

[0078]

[0079]

[0080]

[0081] In the above formula, They represent the trajectory sensitivity of the vehicle yaw rate to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively;

[0082] Defining the roll angle For each parameter θ p Track sensitivity:

[0083]

[0084]

[0085]

[0086]

[0087] In the above formula, They represent the trajectory sensitivity of the vehicle roll angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

[0088] The light electric vehicle load parameter sensitivity analysis method of the present invention is to calculate the average value of the absolute value of the trajectory sensitivity by the following formula in step S3 and compare the values ​​to quantify the analysis sensitivity:

[0089]

[0090] In the above formula, represents the average value of the trajectory sensitivity of the i-th system state variable to the j-th parameter; K represents the total number of sampling points of the system trajectory sensitivity, which is the ratio of the system running time to the sampling time;

[0091] Define the longitudinal velocity V x For each parameter θ p The average absolute value of the trajectory sensitivity is:

[0092]

[0093]

[0094]

[0095]

[0096] In the above formula, are the average values ​​of the vehicle longitudinal velocity sensitivity to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively;

[0097] Define the center of mass sideslip angle β for each parameter θ p The average absolute value of the trajectory sensitivity is:

[0098]

[0099]

[0100]

[0101]

[0102] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle center of mass sideslip angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0103] Define the roll angular velocity r x For each parameter θ p The average absolute value of the trajectory sensitivity is:

[0104]

[0105]

[0106]

[0107]

[0108] In the above formula, are the average values ​​of the vehicle roll angular velocity sensitivity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0109] Define the yaw rate r z For each parameter θ p The average absolute value of the trajectory sensitivity is:

[0110]

[0111]

[0112]

[0113]

[0114] In the above formula, are the average values ​​of the trajectory sensitivity of the vehicle yaw rate to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0115] Defining the roll angle For each parameter θ p The average absolute value of the trajectory sensitivity is:

[0116]

[0117]

[0118]

[0119]

[0120] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle roll angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

[0121] The light electric vehicle load parameter sensitivity analysis method described in the present invention is characterized by: determining the sensitivity of the vehicle longitudinal speed, vehicle center of mass sideslip angle, vehicle roll angular velocity, and vehicle yaw angular velocity by calculating and comparing the average value of the absolute value of the trajectory sensitivity.

[0122] Beneficial Effects

[0123] The light electric vehicle load parameter sensitivity analysis method provided by the present invention, in the process of establishing the vehicle nonlinear dynamic model, takes into account the uncertainty of the light electric vehicle load parameters, such as the load mass, moment of inertia and center of mass position of the whole vehicle and the changes in related geometric parameters when passengers or cargo are loaded, and establishes a nonlinear dynamic model for the light electric vehicle load parameter sensitivity analysis.

[0124] The light electric vehicle load parameter sensitivity analysis method provided by the present invention adopts the trajectory sensitivity perturbation method to define the sensitivity of the light electric vehicle load parameters, quantitatively analyzes and studies the influence of the load parameters on the key dynamic control and characteristics of the vehicle, provides relevant theoretical basis for the active safety control of light electric vehicles, and is beneficial to improving the active safety of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0125] Figure 1 The present invention is a flow chart of a light electric vehicle load parameter sensitivity analysis method.

[0126] Figure 2 The invention discloses a load parameter sensitivity analysis dynamics model for a light electric vehicle taking loading into consideration.

[0127] Figure 3 It is the sensitivity analysis result of the vehicle center of mass sideslip angle trajectory of the present invention. DETAILED DESCRIPTION

[0128] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0129] A light electric vehicle load parameter sensitivity analysis method comprises the following steps:

[0130] (1) Establish a nonlinear dynamic model for load parameter sensitivity analysis of light electric vehicles

[0131] For light electric vehicles, which are electric vehicles with a total mass of less than or equal to 1000KG, consider the changes in vehicle load parameters, vehicle center of mass position and geometric parameters when passengers or cargo are loaded. Figure 1 As shown. The nonlinear dynamic equation model for load parameter sensitivity analysis of light electric vehicles is established:

[0132] Longitudinal Movement:

[0133]

[0134]

[0135] Lateral Movement:

[0136]

[0137]

[0138] Yaw and roll motion:

[0139]

[0140]

[0141] When passengers or cargo are loaded, the yaw moment of inertia of the electric vehicle and the center of mass of the vehicle will change. Assume that the center of mass of the loaded mass is relative to the coordinate vector r = (x p ,y p ,z p ), where x p ,y p 、z p are the longitudinal, lateral and vertical coordinates of the load relative to the vehicle coordinate system, assuming that the load m p is loaded, and the total mass of the loaded vehicle is m n =m s +m p .

[0142] The velocity V at the new center of mass can be calculated from the velocity V at the original center of mass 0 calculate:

[0143] V=V 0 +r×r n

[0144] We can further obtain the equation at the original center of mass:

[0145]

[0146] The equation for the rotational motion of the vehicle body is:

[0147]

[0148] In the above formula, V, V 0 They represent the longitudinal, lateral and vertical velocity vectors of the vehicle when loaded and unloaded, respectively, and V = [V x ,V y ,V z ] T , r. represents the vehicle roll, pitch and yaw angular velocity vectors and their antisymmetric matrices, and r = [r x ,r y ,r z ] T , M represents the external torque, and M=[M x ,M y ,M z ] T ;x n ,y n 、z n Respectively represent the longitudinal, lateral and vertical coordinates of the center of mass of the vehicle after loading (m), and r n =[x n ,y n ,z n ] T .

[0149] Then we can get the new center of mass position coordinates in the original coordinate system:

[0150]

[0151] At the same time, when passengers or cargo are loaded, their related geometric parameters also change accordingly:

[0152]

[0153] In the above formula, m n 、m p Respectively represent the vehicle mass and loaded mass (kg); l f , l r Respectively represent the horizontal distance from the center of mass to the front and rear axles of the vehicle after loading (m); b l 、b r Respectively represent the horizontal distance from the center of mass to the center of the left and right wheels after loading (m); I x ,I z ,I xz They represent the roll moment of inertia of the vehicle around the x-axis, the yaw moment of inertia around the z-axis, and the product of inertia of the vehicle's roll and yaw motions after loading (kg·m 2 );h n Indicates the distance of the roll axis from the ground after loading (m);

[0154] After loading, the corresponding moment of inertia of the vehicle dynamics model also changes, and the calculation formula is as follows:

[0155]

[0156] At the same time, it is noticed that the calculation-related parameters of the dynamic model, such as the vertical load of the tire, the tire sideslip angle and the tire longitudinal slip rate, all change accordingly after loading.

[0157] (2) Trajectory sensitivity analysis of load parameters of light electric vehicles

[0158] According to the established nonlinear dynamic model for light electric vehicle load parameter sensitivity analysis, the dynamic system state equation for light electric vehicle load parameter sensitivity analysis can be obtained:

[0159]

[0160] In the formula, x s represents the system state vector; represents the system parameter vector; u represents the system input; t represents the time variable; x s (0) represents the value of the system state vector at the initial moment.

[0161]

[0162] θ p =[m p x p y p z p ] T

[0163] For the state equation of the dynamic system of light electric vehicles, the trajectory sensitivity of the load parameters of light electric vehicles is defined as:

[0164]

[0165]

[0166] In the above formula, represents the trajectory sensitivity of the i-th system state variable to the j-th parameter; k represents the system time sampling point.

[0167] For the relatively complex state equation system of the dynamic system of light electric vehicles, the numerical method is used to calculate the trajectory sensitivity to reduce the difficulty of calculation, and the median method is further used to improve the calculation accuracy of the trajectory sensitivity as follows:

[0168]

[0169] In the above formula, Indicates the rated value of the system parameter; Represents the state variable value of the system when the parameter is the rated value.

[0170] The trajectory sensitivity is calculated based on a single factor disturbance as follows, where the longitudinal velocity V is defined as x For each parameter θp The trajectory sensitivity is:

[0171]

[0172]

[0173]

[0174]

[0175] In the above formula, m p ′、x p ′、y p ′、z p ′ respectively represents the values ​​of the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position after the rated values ​​are perturbed; They represent the trajectory sensitivity of the vehicle longitudinal velocity to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively;

[0176] Define the center of mass sideslip angle β for each parameter θ p Track sensitivity:

[0177]

[0178]

[0179]

[0180]

[0181] In the above formula, They represent the trajectory sensitivity of the vehicle center of mass sideslip angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0182] Define the roll angular velocity r x For each parameter θ p Track sensitivity:

[0183]

[0184]

[0185]

[0186]

[0187] In the above formula, They represent the trajectory sensitivity of the vehicle roll angular velocity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0188] Define the yaw rate r z For each parameter θ p Track sensitivity:

[0189]

[0190]

[0191]

[0192]

[0193] In the above formula, They represent the trajectory sensitivity of the vehicle yaw rate to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively;

[0194] Defining the roll angle For each parameter θ p Track sensitivity:

[0195]

[0196]

[0197]

[0198]

[0199] In the above formula, They represent the trajectory sensitivity of the vehicle roll angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively;

[0200] (3) Quantitative analysis of trajectory sensitivity of light electric vehicle load parameters

[0201] In order to avoid the sensitivity measurement deviation caused by different selection standards, the analysis sensitivity is quantified by defining the average value of the absolute value of the trajectory sensitivity and comparing the size, that is,

[0202]

[0203] In the above formula, represents the average value of the trajectory sensitivity of the i-th system state variable to the j-th parameter; K represents the total number of sampling points of the system trajectory sensitivity, which is the ratio of the system running time to the sampling time.

[0204] Define the longitudinal velocity V x For each parameter θ p The average absolute value of the trajectory sensitivity is:

[0205]

[0206]

[0207]

[0208]

[0209] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle longitudinal velocity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

[0210] Define the center of mass sideslip angle β for each parameter θ p The average absolute value of the trajectory sensitivity

[0211]

[0212]

[0213]

[0214]

[0215] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle's center of mass sideslip angle to the vehicle's load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

[0216] Define the roll angular velocity r x For each parameter θ p The average absolute value of the trajectory sensitivity is:

[0217]

[0218]

[0219]

[0220]

[0221] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle roll angular velocity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

[0222] Define the yaw rate r z For each parameter θ p The average absolute value of the trajectory sensitivity

[0223]

[0224]

[0225]

[0226]

[0227] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle's yaw rate to the vehicle's load mass and the longitudinal, lateral, and vertical coordinates of the load position, respectively.

[0228] Defining the roll angle For each parameter θ p The average absolute value of the trajectory sensitivity

[0229]

[0230]

[0231]

[0232]

[0233] In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle roll angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

[0234] (4) Conclusions of quantitative analysis of the sensitivity of load parameters of light electric vehicles

[0235] Using the trajectory sensitivity quantitative analysis method of light electric vehicle load parameters, it can be determined that among the load parameters, the vehicle longitudinal velocity V x Load mass m p The most sensitive vertical coordinate value z of the load position p Least sensitive, z p The impact is almost negligible.

[0236] The vehicle's center of mass sideslip angle β also has an effect on the load mass m p The highest sensitivity is y, followed by the lateral coordinate y of the load position. p , vertical coordinate x p , vertical coordinate z p , and the mass center side slip angle β is related to the vertical coordinate z p The sensitivity of β to m is also very low, so this effect can basically be ignored. p ,y p 、x p The sensitivity to z is much greater than that to p impact.

[0237] Vehicle roll angular velocity r x The lateral coordinate y of the load position pThe most sensitive, followed by the load mass m p , vertical coordinate x p and the vertical coordinate z p .

[0238] The order of sensitivity of yaw rate to parameters is m p ,y p 、x p 、z p For the roll angle The influence of vehicle load position on the lateral coordinate y p and load mass m p Much larger than the horizontal coordinate x p and the vertical coordinate z p , and y p and m p The degree of impact of the two is not much different.

[0239] Combining all the above analysis, we can draw the following conclusions: the longitudinal speed V x For m p The sensitivity of x is much higher than other parameters. p ,y p Secondly, z p The least sensitive and can be ignored. The sideslip angle β and the yaw rate r z The sensitivity ranking of load parameters is m p >y p >x p >z p , and z p The influence of the roll angular velocity r is very weak. x Then for y p and m p The most sensitive to x p and z p Relatively insensitive. Roll angle For m p and p The sensitivity of is large and close, and the influence of both is much greater than x p and z p .

[0240] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A light electric vehicle load parameter sensitivity analysis method, characterized in that: The analysis steps are as follows: S1. Establish a nonlinear dynamic equation model for load parameter sensitivity analysis of light electric vehicles; According to the dynamic characteristics of longitudinal motion, lateral motion, yaw and roll motion in the light electric vehicle system, a nonlinear dynamic equation model for load parameter sensitivity analysis of light electric vehicles is established through the changes in load parameters and vehicle center of mass position when the light electric vehicle is loaded with passengers or cargo; S2, performing trajectory sensitivity analysis on the nonlinear dynamic equation model of the light electric vehicle with sensitive load parameters established in step S1; By obtaining the dynamic system state equation of light electric vehicle load parameter sensitivity analysis, the trajectory sensitivity of light electric vehicle load parameters is defined, the median method is used to improve the calculation accuracy of trajectory sensitivity, and the sensitivity analysis method of light electric vehicle load parameters is established; The dynamic system state equation for light electric vehicle load parameter sensitivity analysis is as follows: In the formula, x s represents the system state vector; represents the system parameter vector; u represents the system input; t represents the time variable; x s (0) represents the value of the system state vector at the initial moment; In the above dynamic system state equation, θ p [m p x p y p z p ] Τ For the state equation of the light electric vehicle dynamic system, the trajectory sensitivity of the light electric vehicle load parameters is defined as: In the above formula, represents the trajectory sensitivity of the i-th system state variable to the j-th parameter; k represents the system time sampling point; For the relatively complex state equation system of the dynamic system of light electric vehicles, the numerical method is used to calculate the trajectory sensitivity to reduce the difficulty of calculation, and the median method is further used to improve the calculation accuracy of the trajectory sensitivity as follows: In the above formula, Indicates the rated value of the system parameter; Indicates the state variable value of the system when the parameter is the rated value; The trajectory sensitivity is calculated based on a single factor disturbance as follows, where the longitudinal velocity V is defined as x For each parameter θ p The trajectory sensitivity is: In the above formula, m p ′、x p ′、y p ′、z p ′ respectively represents the values ​​of the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position after the rated values ​​are perturbed; They represent the trajectory sensitivity of the vehicle longitudinal velocity to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively; Define the center of mass sideslip angle β for each parameter θ p Track sensitivity: In the above formula, They represent the trajectory sensitivity of the vehicle center of mass sideslip angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively; Define the roll angular velocity r x For each parameter θ p Track sensitivity: In the above formula, They represent the trajectory sensitivity of the vehicle roll angular velocity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively; Define the yaw rate r z For each parameter θ p Track sensitivity: In the above formula, They represent the trajectory sensitivity of the vehicle yaw rate to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively; Defining the roll angle For each parameter θ p Track sensitivity: In the above formula, They represent the trajectory sensitivity of the vehicle roll angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively; S3. By quantitatively analyzing the sensitivity of the light electric vehicle load parameters, the average value of the absolute value of the trajectory sensitivity is defined, and the average value of the absolute value of the trajectory sensitivity is calculated and compared for quantitative analysis, so as to obtain the quantitative analysis conclusion of the sensitivity of the light electric vehicle load parameters; 2. The light electric vehicle load parameter sensitivity analysis method according to claim 1 is characterized in that: The steps of establishing a nonlinear dynamic model for light electric vehicle load parameter sensitivity analysis in step S1 are as follows: The initial longitudinal motion of the vehicle without passengers or cargo is expressed as: Lateral motion expression: The yaw and roll motion expressions are: When a light electric vehicle is loaded with passengers or cargo, the yaw moment of inertia and the center of mass of the vehicle will change. The center of mass of the loaded mass is located relative to the coordinate vector of the original coordinate system: r = (x p ,y p ,z p ); where x p ,y p 、z p are the longitudinal, lateral and vertical coordinates of the load relative to the vehicle coordinate system, respectively; Load m p The total mass of the loaded vehicle is: m n =m s +m p ; The velocity V at the new center of mass can be calculated from the velocity V at the original center of mass 0 It is expressed by the following formula: V=V 0 +r×r n That is, the equation at the original center of mass is expressed as: The equation for the rotational motion of the body of a light vehicle is defined as: In the above formula, V and V 0 They represent the longitudinal, lateral and vertical velocity vectors of the vehicle when loaded and unloaded, respectively, and V = [V x ,V y ,V z ] Τ , r. represents the vehicle roll, pitch and yaw angular velocity vectors and their antisymmetric matrices, and r = [r x ,r y ,r z ] Τ , M represents the external torque, and M=[M x ,M y ,M z ] Τ ;x n ,y n 、z n Respectively represent the longitudinal, lateral and vertical coordinates of the center of mass of the vehicle after loading (m), and r n =[x n ,y n ,z n ] Τ ; The new center of mass position coordinates in the original coordinate system are obtained by the above formula: At the same time, when a light vehicle is loaded with passengers or cargo, its related geometric parameters also change accordingly: In the above formula, m n 、m p Respectively represent the vehicle mass and loaded mass in kg; l f , l r Respectively represent the horizontal distance m from the center of mass to the front and rear axles of the vehicle after loading; b l 、b r Respectively represent the horizontal distance m from the center of mass to the center of the left and right wheels after loading; I x ,I z ,I xz They represent the roll moment of inertia of the vehicle around the x-axis, the yaw moment of inertia around the z-axis, and the product of inertia of the vehicle's roll and yaw motions after loading, respectively. 2 ; h n It indicates the distance m between the roll axis and the ground after loading; By using the above new center of mass position and the geometric parameter variables after loading passengers or cargo, the corresponding moment of inertia of the light vehicle dynamics model is expressed by the following formula:

3. The light electric vehicle load parameter sensitivity analysis method according to claim 1, characterized in that: The analytical sensitivity is quantified by calculating the average value of the absolute value of the trajectory sensitivity in step S3 by the following formula and comparing the values: In the above formula, represents the average value of the trajectory sensitivity of the i-th system state variable to the j-th parameter; K represents the total number of sampling points of the system trajectory sensitivity, which is the ratio of the system running time to the sampling time; Define the longitudinal velocity V x For each parameter θ p The average absolute value of the trajectory sensitivity is: In the above formula, are the average values ​​of the vehicle longitudinal velocity sensitivity to the vehicle load mass, longitudinal, lateral and vertical coordinates of the load position, respectively; Define the center of mass sideslip angle β for each parameter θ p The average absolute value of the trajectory sensitivity is: In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle center of mass sideslip angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively; Define the roll angular velocity r x For each parameter θ p The average absolute value of the trajectory sensitivity is: In the above formula, are the average values ​​of the vehicle roll angular velocity sensitivity to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively; Define the yaw rate r z For each parameter θ p The average absolute value of the trajectory sensitivity is: In the above formula, are the average values ​​of the trajectory sensitivity of the vehicle yaw rate to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively; Defining the roll angle For each parameter θ p The average absolute value of the trajectory sensitivity is: In the above formula, They represent the average values ​​of the trajectory sensitivity of the vehicle roll angle to the vehicle load mass and the longitudinal, lateral and vertical coordinates of the load position, respectively.

4. The light electric vehicle load parameter sensitivity analysis method according to claim 3 is characterized in that: The sensitivity of the vehicle longitudinal velocity, the vehicle center of mass sideslip angle, the vehicle roll angular velocity, and the vehicle yaw angular velocity is determined by calculating the average values ​​of the absolute values ​​of the trajectory sensitivities and comparing them.

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