Distributed driving control method and device based on sliding mode control

Abstract

The embodiment of the invention relates to a distributed driving control method and device based on sliding mode control, and the method comprises the steps: carrying out the weighted combination of the yaw velocity deviation, the side slip angle deviation and the yaw velocity change rate deviation of a vehicle, and selecting a sliding mode surface of a sliding mode control system; determining a target working condition in the vehicle driving process based on at least one of the road adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information of the vehicle, the speed of the vehicle and the stability factor of the vehicle; adjusting a weight coefficient in the sliding mode surface based on the target working condition to obtain a sliding mode surface corresponding to the target working condition; and a control function of the sliding mode control system is determined based on the sliding mode surface, the three-degree-of-freedom model and the approaching rate function, and the vehicle is controlled based on the control function. Therefore, the situation that the vehicle is prone to yawing, and consequently the vehicle is unstable can be effectively avoided, different working conditions can be adapted, the adaptability to the environment is higher, and the safety and stability of the vehicle can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of sliding mode control, and in particular to a distributed drive control method and device based on sliding mode control. Background Art

[0002] Due to the advantage that the four-wheel motors of distributed drive can be controlled independently, the current discussion popularity is gradually increasing. For vehicles with distributed drive, traditional control methods have problems such as low control accuracy and low accuracy. Therefore, it is proposed to use sliding mode variable structure control (i.e., sliding mode control) to control vehicles with distributed drive, and good results have been achieved.

[0003] However, during the steering process of vehicles with distributed drive, problems such as yaw that easily cause vehicle instability are likely to occur. During the process of controlling the vehicle using the traditional sliding mode variable structure control method, the influence of different working conditions is lacking consideration, resulting in the vehicle stability being affected. Summary of the Invention

[0004] The present application provides a control method for distributed straight driving, which can effectively avoid the situation that the vehicle is prone to yaw and cause vehicle instability, considers the influence of working conditions, can adapt to different working conditions, has stronger adaptability to the environment, and can improve the safety and stability of the vehicle.

[0005] In a first aspect, the present application provides a distributed drive control method based on sliding mode control, including:

[0006] Establish a three-degree-of-freedom model of the vehicle;

[0007] Perform weighted combination on the yaw rate deviation, the sideslip angle deviation of the vehicle's center of mass, and the yaw rate change rate deviation of the vehicle, and select the sliding mode surface of the sliding mode control;

[0008] Determine the target working condition during the vehicle's driving process based on at least one of the road surface adhesion coefficient, the lateral acceleration of the vehicle, the vehicle's steering wheel information, the vehicle's speed, and the vehicle's stability factor;

[0009] Adjust the weight coefficient of the yaw rate deviation, the weight coefficient of the sideslip angle deviation of the vehicle's center of mass, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target working condition, and obtain the sliding mode surface corresponding to the target working condition;

[0010] Determine the control function of the sliding mode control based on the sliding mode surface corresponding to the target working condition, the three-degree-of-freedom model, and the reaching law function of the sliding mode control, and control the vehicle based on the control function.

[0011] In a second aspect, the present application provides a distributed drive control device based on sliding mode control, including:

[0012] A model establishment module for establishing a three-degree-of-freedom model of a vehicle;

[0013] A sliding mode surface selection module for performing weighted combination on the yaw rate deviation, the centroid side slip angle deviation, and the yaw rate change rate deviation of the vehicle to select a sliding mode surface for sliding mode control;

[0014] A working condition determination module for determining a target working condition during the driving of the vehicle based on at least one of a road surface adhesion coefficient, a lateral acceleration of the vehicle, a steering wheel information of the vehicle, a speed of the vehicle, and a stability factor of the vehicle;

[0015] A weight coefficient adjustment module for adjusting the weight coefficient of the yaw rate deviation, the weight coefficient of the centroid side slip angle deviation, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target working condition to obtain a target sliding mode surface corresponding to the target working condition;

[0016] A control module for determining a control function of sliding mode control based on the target sliding mode surface, the three-degree-of-freedom model, and an approach rate function of sliding mode control, and controlling the vehicle based on the control function.

[0017] In a third aspect, an embodiment of the present application provides an electronic device, including:

[0018] A memory for storing a computer program;

[0019] A processor for executing the computer program stored in the memory, and when the computer program is executed, implementing the method provided by the embodiment of the present application.

[0020] In a fourth aspect, a computer-readable storage medium provided by an embodiment of the present application has a computer program stored thereon, and when the computer program is executed by a processor, implementing the method provided by the embodiment of the present application.

[0021] The above technical solution provided by the embodiments of the present application has the following advantages compared with the prior art: The technical solution provided by the embodiments of the present application performs weighted combination on the yaw rate deviation, sideslip angle deviation of the center of mass, and yaw rate change rate deviation of the vehicle, selects a sliding mode surface, and determines the target working condition during the vehicle driving process based on at least one of the road adhesion coefficient, vehicle lateral acceleration, steering wheel information, speed, and stability factor. The weight coefficient in the sliding mode surface is adjusted through the target working condition to obtain the corresponding sliding mode surface, thereby obtaining a control function to achieve vehicle control; that is, by using the yaw rate deviation, sideslip angle deviation of the center of mass, and yaw rate change rate deviation of the vehicle to select the sliding mode surface, the vehicle yaw rate can approach the desired angular velocity, the sideslip angle of the vehicle center of mass can approach the desired sideslip angle of the center of mass, and the yaw rate change rate of the vehicle can approach the desired angular velocity change rate, which can effectively avoid the situation of vehicle yaw and instability; by determining the working condition during the current vehicle driving process through the road adhesion coefficient, lateral acceleration of the vehicle, steering wheel information, vehicle speed, and stability factor, and adjusting the weight coefficient in the sliding mode surface through the working condition, the influence of the working condition is considered, so that the vehicle control can adapt to different working conditions, has stronger environmental adaptability, makes the vehicle control more stable, and can better respond to the driver's intention and maintain the handling stability of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] One or more embodiments are illustrated by way of example in the corresponding pictures in the accompanying drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the drawings do not constitute a proportional limitation.

[0025] Figure 1 It is a flowchart of a distributed drive control method based on sliding mode control provided by the embodiments of the present application;

[0026] Figure 2 It is a flowchart of adjusting the weight coefficient of the yaw rate deviation, the weight coefficient of the sideslip angle deviation of the center of mass, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target working condition provided by the embodiments of the present application;

[0027] Figure 3 Flow chart of a distributed drive control method based on sliding mode control provided by an embodiment of the present application;

[0028] Figure 4 Block diagram of a distributed drive control device based on sliding mode control provided by an embodiment of the present application;

[0029] Figure 5 Schematic structural diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0031] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0032] To solve the technical problems in the prior art that in the steering process of a vehicle with distributed drive, the vehicle is prone to yaw and thus loses stability, and that the traditional control method lacks consideration of different working conditions and thus affects the vehicle stability, the embodiments of the present application provide a distributed drive control method and device based on sliding mode control, which can effectively avoid the situation of vehicle instability, can be applicable to different working conditions, have stronger environmental adaptability, and can improve the vehicle stability and safety.

[0033] Figure 1 Flow chart of a distributed drive control method based on sliding mode control provided by an embodiment of the present application. The method can be executed by a distributed drive control device based on sliding mode control, and the device can be configured in an electronic device such as an on-vehicle device.

[0034] As Figure 1 shown, the technical solution provided by the embodiment of the present application includes the following steps:

[0035] Step 101: Establish a three-degree-of-freedom model of the vehicle.

[0036] In this embodiment, for the vehicle steering motion, considering the lateral motion dimension, longitudinal motion dimension, and yaw motion dimension of the vehicle, a three-degree-of-freedom model of the vehicle is established based on these three dimensions.

[0037] In an alternative embodiment, establishing a three-degree-of-freedom model of the vehicle includes:

[0038] Determining the three-degree-of-freedom model of the vehicle based on the following formula:

[0039]

[0040] Wherein, in the above formula (1), F x1 , F x2 , F x3 and F x4 are the driving forces of the four wheels respectively; F y1 , F y2 , F y3 and F y4 are the lateral forces of the four wheels respectively; F f is the frictional resistance, F w is the air resistance, F i is the ramp resistance, F j is the acceleration resistance; F D is the steering resistance; r is the wheel radius;

[0041] a x is the longitudinal acceleration of the vehicle; a y is the lateral acceleration of the vehicle; m is the mass of the vehicle; a is the distance from the front axle to the center of mass, b is the distance from the rear axle to the center of mass, δ is the front wheel steering angle, d is the distance between the left and right wheels; M zd is the yaw moment; I z is the moment of inertia; ω is the vehicle yaw angular velocity; v x is the longitudinal speed of the vehicle; β is the center of mass sideslip angle of the vehicle.

[0042] The reason for establishing a three-degree-of-freedom model of the vehicle in the embodiments of the present application is that subsequently, in order to calculate the control function of the sliding mode control and analyze the influencing factors associated with the vehicle steering motion through the three-degree-of-freedom model of the vehicle, so as to establish the sliding mode surface of the sliding mode control.

[0043] Step 102: Perform weighted combination on the yaw angular velocity deviation, center of mass sideslip angle deviation, and yaw angular velocity change rate deviation of the vehicle, and select the sliding mode surface of the sliding mode control.

[0044] In the embodiments of the present application, during the steering process of the vehicle, the handling and stability control of the vehicle is very important. When the steering wheel is turned, it is necessary to control the vehicle torque so that the yaw rate of the vehicle reaches the desired yaw rate of the vehicle. When the vehicle speed is relatively high, if the torque control accuracy of the vehicle is low, the vehicle will yaw. Therefore, it is necessary to control the yaw rate of the vehicle to avoid vehicle instability. In addition, during the steering process of the vehicle, it is necessary to make the vehicle combine the driver's intention to reach the desired yaw rate as expected by the driver. Therefore, the yaw rate needs to be considered as a factor for the sliding mode surface. In summary, the yaw rate deviation determined by the vehicle yaw rate and the desired yaw rate is selected as the factor for the sliding mode surface selection, so as to control the vehicle yaw rate to reach the desired yaw rate. In addition, the yaw rate change rate of the vehicle will also affect the yaw situation of the vehicle. In order to avoid the vehicle yaw caused by the yaw rate change rate of the vehicle, the yaw rate change rate deviation determined by the vehicle yaw rate change rate and the desired angular velocity change rate is selected as the factor for the sliding mode surface selection, so that the yaw rate change rate of the vehicle can be controlled to reach the desired angular velocity change rate, effectively avoiding the vehicle yaw situation.

[0045] In this embodiment, the yaw situation of the vehicle can also be reflected by the yaw angle. Also, because the yaw angle is related to the sideslip angle of the center of mass, the sideslip angle of the center of mass of the vehicle can be controlled as a weighting for the vehicle yaw control. In order to avoid the vehicle yaw situation, therefore, the sideslip angle deviation of the center of mass of the vehicle determined by the sideslip angle of the center of mass of the vehicle and the desired sideslip angle of the center of mass can be selected as the factor for the sliding mode surface selection, so as to control the sideslip angle of the center of mass of the vehicle to reach the desired sideslip angle of the center of mass, effectively avoiding the vehicle yaw situation.

[0046] In this embodiment, the yaw rate deviation of the vehicle can be the difference between the vehicle yaw rate and the desired yaw rate; the sideslip angle deviation of the center of mass can be the difference between the sideslip angle of the center of mass of the vehicle and the desired sideslip angle; the yaw rate change rate deviation can be the difference between the yaw rate change rate of the vehicle and the desired yaw rate change rate. Among them, the vehicle yaw rate can be understood as the actual yaw rate of the vehicle; the sideslip angle of the center of mass of the vehicle can be understood as the actual sideslip angle of the center of mass of the vehicle; the yaw rate change rate of the vehicle can be understood as the actual angular velocity change rate of the vehicle. Among them, the relationship between the vehicle yaw angle and the sideslip angle of the center of mass of the vehicle is based on the following formula:

[0047] φ = θ - β (2)

[0048] Wherein, in the above formula (2), φ is the vehicle yaw angle; θ is the vehicle heading angle. Among them, the vehicle heading angle is the angle between the vehicle center of mass velocity and the horizontal axis in the ground coordinate system; the sideslip angle of the center of mass of the vehicle is the angle between the direction of the vehicle center of mass velocity and the direction of the vehicle head.

[0049] Among them, the desired yaw rate can be determined based on parameters such as the steering wheel angle and the throttle pedal opening. Specifically, the specific calculation of the desired angular velocity can refer to the following formula: Among them, δ′ is the steering wheel angle, L is the wheelbase of the vehicle, K is the vehicle stability factor, i is the wheel steering angle ratio, m is the vehicle mass, a and b are the distances from the center of mass to the front axle and the rear axle respectively, K f and K r are the stiffnesses of the front axle and the rear axle respectively; u is the peak adhesion coefficient of the road surface; g is the acceleration due to gravity. The desired angular velocity can be obtained through the above formula. Among them, the derivative of the desired angular velocity can be obtained to get the desired angular velocity change rate, or it can also be determined according to empirical calibration; among them, according to the formula the change curve of the sideslip angle of the center of mass can be obtained, which can be obtained by calibration on the curve, or it can also be obtained according to empirical calibration. Among them, V y is the lateral velocity of the vehicle.

[0050] In this embodiment, specifically, the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation of the vehicle can be linearly weighted and combined to obtain the sliding surface of the sliding mode control; or it can also be that the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation of the vehicle are weighted and combined in an exponential form, or it can also be that the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation of the vehicle are weighted and combined in an integral form to meet the desired yaw rate, the desired yaw rate change rate, and the desired sideslip angle of the center of mass, so as to make the system stable and avoid the situation of vehicle yaw and instability.

[0051] In an alternative embodiment, optionally, the sliding surface of the sliding mode control is selected based on the following formula:

[0052]

[0053] Among them, S is the switching function of the sliding surface; (ω - ω xd ) is the yaw rate deviation of the vehicle; ω is the vehicle yaw rate; ω xd is the desired yaw rate; ξ 1 is the weight coefficient of the yaw rate deviation;

[0054] Among them, (β - β xd ) is the sideslip angle deviation of the center of mass of the vehicle; β is the sideslip angle of the center of mass of the vehicle, β xd is the desired sideslip angle of the center of mass; ξ 2 is the weight coefficient of the sideslip angle deviation of the center of mass;

[0055] Among them, is the yaw rate change rate deviation of the vehicle; is the yaw rate change rate of the vehicle, is the desired yaw rate change rate; ξ 3 is the weight coefficient of the yaw rate change rate deviation. The above formula (3) is established by linearly combining the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation. The sliding mode surface established in this way can simplify the operation and improve the response speed when calculating the control function.

[0056] Step 103: Determine the target driving condition of the vehicle during driving based on at least one of the road surface adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information of the vehicle, the speed of the vehicle, and the stability factor of the vehicle.

[0057] In this embodiment, during the steering process of distributed drive, the state of the vehicle is affected by various driving conditions. For example, it is affected by the driving condition and the driver's demand. Therefore, it is necessary to distinguish different driving conditions. Among them, the driving condition can be reflected by the road surface adhesion coefficient, the stability factor, etc., and the driver's demand is reflected by the steering wheel angle, the steering wheel angle change rate, the speed of the vehicle, the lateral acceleration of the vehicle, etc.

[0058] In an optional implementation manner, the determining the target driving condition of the vehicle during driving based on at least one of the road surface adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information of the vehicle, the speed of the vehicle, and the stability factor of the vehicle includes: during the driving of the vehicle, if any one of the following driving conditions occurs, the occurring single driving condition is used as the target driving condition, and if at least two of the following driving conditions occur, the target driving condition is used as a composite driving condition:

[0059] The road surface adhesion coefficient and the road surface adhesion coefficient change rate change;

[0060] The lateral acceleration of the vehicle changes;

[0061] The steering wheel angle and the steering wheel angle change rate change;

[0062] The speed of the vehicle changes;

[0063] The magnitude of the stability factor of the vehicle changes.

[0064] Among them, optionally, the working conditions in which the road surface adhesion coefficient and the change rate of the road surface adhesion coefficient change can be an increase or a decrease in the road surface adhesion coefficient, and whether the change rate of the road surface adhesion coefficient is greater than the first target change rate threshold. The working conditions in which the lateral acceleration of the vehicle changes can specifically be an increase or a decrease in the lateral acceleration of the vehicle. The working conditions in which the steering wheel angle and the change rate of the steering wheel angle change can be an increase or a decrease in the steering wheel angle, or whether the change rate of the steering wheel angle is greater than the second target change rate threshold. The working conditions in which the speed of the vehicle changes can be an increase or a decrease in the speed of the vehicle. The working conditions in which the magnitude of the vehicle stability factor K changes can be that the vehicle stability factor K changes from being greater than or equal to 0 to less than 0, or the vehicle stability factor changes from less than 0 to greater than or equal to 0.

[0065] In this embodiment, if the target working condition includes at least one of the above individual working conditions, it is necessary to adjust each weight coefficient based on the target working condition. Among them, the weight coefficients in the sliding mode surfaces corresponding to the above different working conditions are also different.

[0066] Step 104: Adjust the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target working condition to obtain the sliding mode surface corresponding to the target working condition.

[0067] In this embodiment, if the target working condition is an individual working condition, the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, and the weight coefficient of the yaw rate change rate deviation corresponding to the individual working condition are the weight coefficients of the corresponding parameters in the sliding mode surface corresponding to the target working condition. If the target working condition is a composite working condition including at least two individual working conditions, the weight coefficients of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, and the weight coefficient of the yaw rate change rate deviation corresponding to each individual working condition are correspondingly processed to obtain the weight coefficients of the corresponding parameters in the sliding mode surface corresponding to the composite working condition. Among them, the parameters in the sliding mode surface can be the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, or the weight coefficient of the yaw rate change rate deviation.

[0068] Specifically, if the target working condition is a composite working condition, the weight coefficient corresponding to the parameter in the sliding mode surface can be to sum and normalize the weight coefficients of the parameters corresponding to at least two individual working conditions included in the target working condition, or it can also be to consider the influence of each individual working condition on the parameter, and then perform weighted processing on the weight coefficients of the parameters corresponding to each individual working condition, or there can also be other forms.

[0069] Thus, by adjusting the weight coefficient based on the target working condition, a corresponding sliding mode surface can be obtained, and subsequent corresponding control can be performed for different working conditions, improving the control accuracy of the vehicle and effectively avoiding the situation of yaw instability of the vehicle.

[0070] Step 105: Determine the control function of the sliding mode control based on the sliding mode surface corresponding to the target working condition, the three-degree-of-freedom model, and the reaching law function of the sliding mode control, and control the vehicle based on the control function.

[0071] In this embodiment, an exponential reaching law function, or a constant velocity reaching law function, or a general reaching law function, etc. can be adopted. Among them, in order to reduce the disturbance of the sliding mode control, an exponential reaching function can be adopted.

[0072] Among them, the exponential reaching law function can be: k > 0, where ε is the gain coefficient and k is the reaching law, is the exponential reaching term.

[0073] In this embodiment, the first derivative of the sliding mode surface can be obtained to get the dynamic equation of the sliding mode control. Through the dynamic equation of the sliding mode control, the three-degree-of-freedom model in the above formula (1), and the reaching law function, the control function of the sliding mode control can be obtained. Among them, the control function can be the control function of the vehicle torque.

[0074] The technical solution provided by the embodiment of the present application performs weighted combination through the yaw rate deviation, sideslip angle deviation of the vehicle's center of mass, and yaw rate change rate deviation of the vehicle, selects the sliding mode surface, and determines the target working condition during the vehicle's driving process based on at least one of the road surface adhesion coefficient, vehicle lateral acceleration, steering wheel information, speed, and stability factor. The weight coefficient in the sliding mode surface is adjusted through the target working condition to obtain the corresponding sliding mode surface, thereby obtaining the control function to control the vehicle; that is, by using the yaw rate deviation, sideslip angle deviation of the vehicle's center of mass, and yaw rate change rate deviation of the vehicle to select the sliding mode surface, the vehicle's yaw rate can approach the desired angular velocity, the sideslip angle of the vehicle's center of mass can approach the desired sideslip angle of the center of mass, and the yaw rate change rate of the vehicle can approach the desired yaw rate change rate, which can effectively avoid the situation of vehicle yaw leading to instability. By determining the working condition during the current vehicle driving process through the road surface adhesion coefficient, vehicle lateral acceleration, steering wheel information, vehicle speed, and stability factor, and adjusting the weight coefficient in the sliding mode surface through the working condition, it can adapt to different working conditions, has stronger environmental adaptability, makes the vehicle control more stable, and can also better respond to the driver's intention and maintain the handling and stability of the vehicle.

[0075] Figure 2It is a flowchart for adjusting the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation in the sliding mode surface based on the target working condition provided by an embodiment of the present application. It is applicable to the case where the target working condition is a single working condition. Based on the process shown in Figure 1 and as shown in Figure 2 , the method includes the following steps:

[0076] Step 201: If the target working condition is that the road surface adhesion coefficient and the change rate of the road surface adhesion coefficient change, determine each weight coefficient in the sliding mode surface based on the current road surface adhesion coefficient and the change rate of the road surface adhesion coefficient.

[0077] In an embodiment of the present application, if the road surface adhesion coefficient changes from high to low and the change rate of the road surface adhesion coefficient is less than the first target change rate threshold, the weight coefficient in the sliding mode surface corresponding to the current road surface adhesion coefficient is used as the weight coefficient in the adjusted sliding mode surface. If the road surface adhesion coefficient changes from high to low and the change rate of the road surface adhesion coefficient is greater than the first target change rate threshold, each weight coefficient in the sliding mode surface corresponding to the first target change rate threshold is used as the weight coefficient in the adjusted sliding mode surface. Among them, the weight coefficient of the yaw rate deviation corresponding to the first target change rate threshold is greater than the weight coefficient of the yaw rate deviation corresponding to the current road surface adhesion coefficient. Among them, during the process of the road surface adhesion coefficient changing from high to low, in the initial period, the road surface adhesion coefficient suddenly changes and the change rate of the road surface adhesion coefficient is large, greater than the first target change rate threshold. The weight coefficient in the sliding mode surface corresponding to the first target change rate threshold is used as the weight coefficient in the adjusted sliding mode surface. After passing through the initial period, the change rate of the road surface adhesion coefficient is basically 0, and then the weight coefficient in the sliding mode surface corresponding to the current road surface adhesion coefficient can be used as the weight coefficient in the adjusted sliding mode surface. In the case where the road surface adhesion coefficient changes from low to high, the weight coefficient in the sliding mode surface corresponding to the current road surface adhesion coefficient can be used as the weight coefficient in the adjusted sliding mode surface.

[0078] Among them, if the road surface adhesion coefficient changes, the weight coefficient of the yaw rate deviation changes inversely with the road surface adhesion coefficient; within the first range of the change in the road surface adhesion coefficient, the weight coefficient of the sideslip angle deviation of the center of mass changes inversely with the road surface adhesion coefficient, and within the second range of the change in the road surface adhesion coefficient, the weight coefficient of the sideslip angle deviation of the center of mass remains unchanged. Specifically, if the road surface adhesion coefficient decreases (changes from high to low), the probability of vehicle instability increases. It is necessary to increase the control weight of the yaw rate, and within the first range of the change in the road surface adhesion coefficient, increase the control weight of the sideslip angle deviation of the center of mass. Therefore, it is necessary to increase the weight coefficient of the yaw rate deviation in the sliding mode surface and within the first range of the change in the road surface adhesion coefficient, increase the weight coefficient of the sideslip angle deviation of the center of mass, so that the yaw rate can reach the desired yaw rate faster and the sideslip angle of the center of mass can reach the desired sideslip angle of the center of mass faster, effectively reducing the probability of vehicle instability. Among them, the corresponding relationship between each weight coefficient in the sliding mode surface and the road surface adhesion coefficient can refer to Table 1.

[0079] Table 1

[0080]

[0081] Through the above Table 1, the first target change rate threshold is 0.2 / s, the first range of the change in the road surface adhesion coefficient can be 0.4 - 0.8, and the second range of the change in the road surface adhesion coefficient can be 0.2 - 0.4. Among them, the change range of the road surface adhesion coefficient is 0 ～ 1.

[0082] Step 202: If the target condition is that the lateral acceleration changes, determine each weight coefficient in the sliding mode surface based on the current lateral acceleration.

[0083] In the embodiment of the present application, if the lateral acceleration changes, the weight coefficient in the sliding mode surface corresponding to the current lateral acceleration is used as the weight coefficient in the adjusted sliding mode surface. Among them, the weight coefficient of the yaw rate deviation changes directly with the lateral acceleration, and within the first range of the change in the lateral acceleration, the weight coefficient of the yaw rate change rate deviation changes directly with the lateral acceleration. Within the second range of the change in the lateral acceleration, the weight coefficient of the yaw rate change rate deviation remains unchanged.

[0084] Specifically, if the target working condition is an increase in lateral acceleration, the centrifugal force acting on the vehicle increases, the lateral force required by the vehicle increases, and the probability of wheel skidding increases. In this case, it is necessary to increase the control weight of the yaw rate, and within the first range of lateral acceleration changes, increase the control weight of the yaw rate change rate. Therefore, in the sliding mode surface, it is necessary to increase the weight coefficient of the yaw rate deviation and increase the weight coefficient of the yaw rate change rate within the first range of lateral acceleration changes, so that the yaw rate and the yaw rate change rate of the vehicle reach the corresponding desired targets, effectively avoiding vehicle skidding. Similarly, if the target working condition is a decrease in lateral acceleration, the control weight of the yaw rate can be reduced and the control weight of the yaw rate change rate can be selectively reduced accordingly. Therefore, in the sliding mode surface, it is necessary to reduce the weight coefficient of the yaw rate deviation and selectively reduce the weight coefficient of the yaw rate change rate. Among them, the corresponding relationship between each weight coefficient in the sliding mode surface and the lateral acceleration can be referred to Table 2.

[0085] Table 2

[0086] <![CDATA[Lateral acceleration k a > <![CDATA[ξ 1 > <![CDATA[ξ 2 > <![CDATA[ξ 3 > <![CDATA[2m / s 2 > 0.3 0.4 0.3 <![CDATA[4m / s 2 > 0.4 0.2 0.4 <![CDATA[6m / s 2 > 0.5 0.1 0.4

[0087] Among them, the change range of the lateral acceleration can be 0 - 6 m / s 2 , and the first range of lateral acceleration changes can be 2 - 4 m / s 2 , and the second range of lateral acceleration changes can be 4 - 6 m / s 2 .

[0088] Step 203: If the target working condition is a change in the steering wheel angle and the steering wheel angle change rate, determine each weight coefficient in the sliding mode surface based on the current steering wheel angle and the steering wheel angle change rate.

[0089] In the embodiment of the present application, if the steering wheel angle increases and the steering wheel angle change rate is less than the second target change rate threshold, the weight coefficient of the sliding mode surface corresponding to the current steering wheel angle is used as the adjusted weight coefficient. If the steering wheel angle increases and the steering wheel angle change rate is greater than the second target change rate threshold, the weight coefficient of the sliding mode surface corresponding to the second target change rate threshold is used as the adjusted weight coefficient. Among them, the weight coefficient of the centroidal side slip angle deviation corresponding to the second target change rate is greater than the weight coefficient of the centroidal side slip angle deviation corresponding to the current steering wheel angle. Among them, during the process of the steering wheel angle changing, if the steering wheel angle change rate is greater than the second target change rate threshold, the weight coefficient of the sliding mode surface corresponding to the second target change rate threshold is used as the adjusted weight coefficient. When waiting for the steering wheel angle change rate to be less than the second target change rate threshold, the weight coefficient of the sliding mode surface corresponding to the current road surface adhesion coefficient is used as the adjusted weight coefficient. Among them, the second target change rate threshold can be 90° / s.

[0090] Among them, during the process of the steering wheel angle changing, the weight coefficient of the yaw rate deviation changes in direct proportion to the steering wheel angle. Specifically, if the steering wheel angle increases, the lateral acceleration increases, the weight of the lateral vehicle speed increases, and the vehicle is prone to skidding. It is necessary to increase the control weight of the yaw rate. Therefore, the weight coefficient of the yaw rate deviation is increased in the sliding mode surface. The intention of the driver corresponding to this working condition is to achieve the purpose of steering and needs to increase the steering wheel angle. At this time, the weight coefficient of the yaw rate deviation needs to be increased in the sliding mode surface. Similarly, if the target working condition is a decrease in the steering wheel angle, the weight coefficient of the yaw rate deviation can be reduced in the sliding mode surface. Among them, the corresponding relationship between the weight coefficients in the sliding mode surface and the steering wheel angle and the steering wheel change rate can be referred to Table 3. Among them, the change range of the steering wheel angle is 0 ～ 90°. When the steering wheel change rate is greater than or equal to 90° / s, the weight coefficient of the sideslip angle deviation is increased in the sliding mode surface.

[0091] Table 3

[0092]

[0093] Step 204: If the target working condition is a change in the vehicle speed, if the target working condition is a change in the vehicle speed, determine each weight coefficient in the sliding mode surface based on the current vehicle speed.

[0094] In the embodiment of the present application, when the vehicle speed changes, the weight coefficient in the sliding mode surface corresponding to the current vehicle speed is used as the weight coefficient in the adjusted sliding mode surface. Among them, the weight coefficient of the yaw rate deviation changes in direct proportion to the vehicle speed, and within the first range of the vehicle speed change, the weight coefficient of the sideslip angle deviation changes in direct proportion to the vehicle speed. Within the second range of the vehicle speed change, the weight coefficient of the sideslip angle deviation remains unchanged.

[0095] Specifically, if the target working condition is an increase in the vehicle speed, in this working condition, the stability of the vehicle needs to be enhanced. It is necessary to increase the control weight of the yaw rate and, within the first range of the vehicle speed change, increase the control weight of the sideslip angle of the center of mass. Therefore, it is necessary to increase the weight coefficient of the yaw rate deviation in the sliding mode surface and, within the first range of the vehicle speed change, increase the weight coefficient of the sideslip angle deviation of the center of mass. Similarly, if the target working condition is a decrease in the vehicle speed, the weight coefficient of the yaw rate deviation in the sliding mode surface can be reduced and the weight coefficient of the sideslip angle deviation of the center of mass can be selectively reduced. Among them, if the target working condition is an increase in the vehicle speed, the intention of the driver corresponding to this working condition is to want to turn quickly, and it is necessary to increase the throttle opening. When the vehicle speed increases, it is necessary to increase the weight coefficient of the yaw rate deviation and selectively increase the weight coefficient of the sideslip angle deviation in the sliding mode surface. Among them, the corresponding relationship between each weight coefficient in the sliding mode surface and the vehicle speed can be referred to Table 4. Among them, the vehicle speed change range can be 60 ～ 180 km / h.

[0096] Table 4

[0097] <![CDATA[Vehicle speed k v > <![CDATA[ξ 1 > <![CDATA[ξ 2 > <![CDATA[ξ 3 > 60 km / h 0.2 0.2 0.6 120 km / h 0.5 0.3 0.2 180 km / h 0.7 0.3 0

[0098] Step 205: If the magnitude of the stability factor of the vehicle changes in the target working condition, determine each weight coefficient in the sliding mode surface based on the comparison result between the stability factor and the preset value.

[0099] In the embodiment of the present application, the preset value can be 0. If the magnitude of the vehicle stability factor K changes, the comparison result between K and 0 can be judged, and the weight coefficient in the sliding mode surface corresponding to the comparison result is used as the weight coefficient in the adjusted sliding mode surface. Among them, the weight coefficient of the yaw rate deviation changes inversely with the vehicle stability factor K. Specifically, if the vehicle stability factor decreases, the weight coefficient of the yaw rate deviation can be increased, or if the vehicle stability factor K increases, the weight coefficient of the yaw rate deviation can be decreased.

[0100] Specifically, the vehicle stability factor K is the main parameter for judging the vehicle state, where a and b are the distances from the center of mass to the front axle and the rear axle respectively, K f and K rare the stiffnesses of the front axle and the rear axle respectively, L is the wheelbase of the vehicle, and m is the mass of the vehicle. When K>0, the vehicle is understeering; when K = 0, the vehicle is neutrally steering; when K<0, the vehicle is oversteering. When the vehicle is oversteering, the same steering wheel angle will cause a sharp increase in the yaw rate, and it is necessary to increase the control weight of the yaw rate. Therefore, if the vehicle stability factor K decreases (changes from greater than 0 to equal to 0, or from equal to 0 to less than 0), it is necessary to increase the weight coefficient of the yaw rate deviation in the sliding mode surface. Similarly, if the vehicle stability factor K increases (changes from less than 0 to equal to 0, or from equal to 0 to greater than 0), the weight coefficient of the yaw rate deviation in the sliding mode surface is decreased. Among them, the corresponding relationship between each weight coefficient in the sliding mode surface and the stability factor can be referred to Table 5.

[0101] Table 5

[0102] <![CDATA[Stability factor K k k > <![CDATA[ξ 1 > <![CDATA[ξ 2 > <![CDATA[ξ 3 > K>0 0.2 0.2 0.6 K＝0 0.3 0.3 0.4 K<0 0.8 0.1 0

[0103] Thus, when the target working conditions are respectively the change of road adhesion coefficient, the change of lateral acceleration, the change of steering wheel angle and the change rate of steering wheel angle, the change of vehicle speed, and the change of the vehicle stability factor, etc., by correspondingly adjusting the weight coefficients in the sliding mode surface, the vehicle can be controlled according to the working conditions, making the vehicle control more stable and more adaptable to the environment. When the target working conditions are respectively the change of steering wheel angle and the change rate of steering wheel angle, the change of vehicle speed, etc., by adjusting the weight coefficients in the sliding mode surface, the driver's intention can be better responded to, and the vehicle handling stability can be better maintained.

[0104] Figure 3 is a flowchart of a distributed drive control method based on sliding mode control provided by an embodiment of the present application. This embodiment is applicable to the target working condition of a composite working condition. As Figure 3 shown, the method includes the following steps:

[0105] Step 301: Establish a three-degree-of-freedom model of the vehicle;

[0106] Step 302: Weight and combine the yaw rate deviation, the centroid side slip angle deviation and the yaw rate change rate deviation of the vehicle, and select the sliding mode surface of the sliding mode control;

[0107] Step 303: Determine the target working condition during the vehicle driving process based on at least one of the road adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information of the vehicle, the vehicle speed, and the vehicle stability factor.

[0108] Step 304: Based on the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to each individual operating condition included in the target operating condition, respectively, determine the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to the target operating condition, respectively, to obtain the sliding mode surface corresponding to the target operating condition.

[0109] Step 305: Determine the control function of the sliding mode control based on the sliding mode surface corresponding to the target operating condition, the three-degree-of-freedom model, and the reaching law function of the sliding mode control, and control the vehicle based on the control function.

[0110] Among them, the introductions of steps 301-303 and step 305 can refer to the introductions of the above embodiments. The following is an introduction to step 304.

[0111] In this embodiment, if the target operating condition includes at least two individual operating conditions, the target operating condition is a composite operating condition, and the introduction of the individual operating conditions can refer to the above embodiments. The adjustment of the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to each individual operating condition can refer to the introductions of the above embodiments. Each individual operating condition corresponds to a set of weight coefficients, that is, each individual operating condition has corresponding weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation.

[0112] In the case where the target operating condition is a composite operating condition, the weight coefficient of the yaw rate deviation in the sliding mode surface can be achieved in the following ways: summing and normalizing the weight coefficients of the yaw angle deviation corresponding to each individual operating condition included in the target operating condition, or considering the influence of each individual operating condition on vehicle control, and then weighting the weight coefficients of the yaw rate deviation corresponding to each individual operating condition, or it can also be other implementation methods. Similarly, the weight coefficients of the sideslip angle deviation of the center of mass and the yaw rate change rate deviation in the sliding mode surface can also adopt the implementation methods of the weight coefficient of the yaw rate deviation described above.

[0113] In an alternative embodiment, based on the weight coefficients of the yaw rate deviation, the sideslip angle deviation, and the yaw rate change rate deviation corresponding to each individual working condition included in the target working condition, respectively, determining the weight coefficients of the yaw rate deviation, the sideslip angle deviation, and the yaw rate change rate deviation corresponding to the target working condition includes: summing and normalizing the weight coefficients of the yaw rate deviation corresponding to each individual working condition included in the target working condition to obtain the weight coefficient of the yaw rate deviation corresponding to the target working condition; summing and normalizing the weight coefficients of the sideslip angle deviation corresponding to each individual working condition included in the target working condition to obtain the weight coefficient of the sideslip angle deviation corresponding to the target working condition; summing and normalizing the weight coefficients of the yaw rate change rate deviation corresponding to each working condition included in the target working condition to obtain the weight coefficient of the yaw rate change rate deviation corresponding to the target working condition.

[0114] Optionally, the summing and normalizing the weight coefficients of the yaw rate deviation corresponding to each individual working condition included in the target working condition to obtain the weight coefficient of the yaw rate deviation corresponding to the target working condition includes:

[0115] Determining the weight coefficient of the yaw rate deviation based on the following formula:

[0116]

[0117] Correspondingly, the summing and normalizing the weight coefficients of the sideslip angle deviation corresponding to each individual working condition included in the target working condition to obtain the weight coefficient of the sideslip angle deviation corresponding to the target working condition includes:

[0118] Determining the weight coefficient of the sideslip angle deviation based on the following formula:

[0119]

[0120] Correspondingly, the summing and normalizing the weight coefficients of the yaw rate change rate deviation corresponding to each individual working condition included in the target working condition to obtain the weight coefficient of the yaw rate change rate deviation corresponding to the target working condition includes:

[0121] Determining the weight coefficient of the yaw rate change rate deviation based on the following formula:

[0122]

[0123] where n is the number of individual working conditions included in the target working condition; k μ1 、kμ2 and k μ3 are respectively the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to the working conditions where the road surface adhesion coefficient changes; where k a1 , k a2 and k a3 are respectively the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to the working conditions where the lateral acceleration of the vehicle changes; where k δ1 , k δ2 and k δ3 are respectively the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to the working conditions where the steering wheel angle and the steering wheel angle change rate change; where k v1 , k v2 and k v3 are respectively the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to the working conditions where the vehicle speed changes; where k k1 , k k2 and k k3 are respectively the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation corresponding to the working conditions where the magnitude of the vehicle stability factor changes.

[0124] Thus, in the case where the target working condition is a composite working condition, by summing and normalizing each weight parameter corresponding to each individual working condition included in the target working condition, the weight parameter of the corresponding sliding mode surface is obtained. When there are multiple individual working conditions, the influence of each individual working condition on vehicle control is considered, so that the vehicle control is more stable and the adaptability to the environment is stronger.

[0125] Figure 4 is a structural block diagram of a distributed drive control device based on sliding mode control provided by an embodiment of the present application. As Figure 4 shown, the device includes: a model establishment module 410, a sliding mode surface selection module 420, a working condition determination module 430, a weight coefficient adjustment module 440, and a control module 450.

[0126] Among them, the model establishment module 410 is used to establish a three-degree-of-freedom model of the vehicle;

[0127] The sliding mode surface selection module 420 is used to perform weighted combination on the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation of the vehicle, and select the sliding mode surface of the sliding mode control;

[0128] The operating condition determination module 430 is configured to determine a target operating condition during the vehicle driving based on at least one of a road surface adhesion coefficient, a lateral acceleration of the vehicle, a steering wheel information of the vehicle, a speed of the vehicle, and a stability factor of the vehicle;

[0129] The weight coefficient adjustment module 440 is configured to adjust a weight coefficient of a yaw rate deviation, a weight coefficient of a sideslip angle deviation of the center of mass, and a weight coefficient of a yaw rate change rate deviation in the sliding mode surface based on the target operating condition, so as to obtain a target sliding mode surface corresponding to the target operating condition;

[0130] The control module 450 is configured to determine a control function of the sliding mode control based on the target sliding mode surface, the three-degree-of-freedom model, and an approaching rate function of the sliding mode control, and control the vehicle based on the control function.

[0131] In a possible embodiment, the sliding mode surface selection module 420 is specifically configured to:

[0132] Select a sliding mode surface of the sliding mode control based on the following formula:

[0133]

[0134] where S is a switching function of the sliding mode surface; (ω - ω xd ) is a yaw rate deviation of the vehicle; ω is the yaw rate of the vehicle; ω xd is the desired yaw rate; ξ 1 is the weight coefficient of the yaw rate deviation;

[0135] where (β - β xd ) is a sideslip angle deviation of the center of mass of the vehicle; β is the sideslip angle of the center of mass of the vehicle, β xd is the desired sideslip angle of the center of mass; ξ 2 is the weight coefficient of the sideslip angle deviation of the center of mass;

[0136] where is a yaw rate change rate deviation of the vehicle; is the yaw rate change rate of the vehicle, is the desired yaw rate change rate; ξ 3 is the weight coefficient of the yaw rate change rate deviation.

[0137] In a possible embodiment, the operating condition determination module 430 is specifically configured to:

[0138] During the vehicle driving, if one of the following operating conditions occurs, the occurring single operating condition is used as the target operating condition; if at least two of the following operating conditions occur, the target operating condition is used as a composite operating condition:

[0139] The road surface adhesion coefficient and the change rate of the road surface adhesion coefficient change;

[0140] The lateral acceleration of the vehicle changes;

[0141] The steering wheel angle and the change rate of the steering wheel angle change;

[0142] The speed of the vehicle changes;

[0143] The magnitude of the vehicle stability factor changes.

[0144] In a possible embodiment, the weight coefficient adjustment module 440 is specifically configured to:

[0145] If the target working condition is that the road surface adhesion coefficient and the change rate of the road surface adhesion coefficient change, determine each weight coefficient in the sliding mode surface based on the current road surface adhesion coefficient and the change rate of the road surface adhesion coefficient;

[0146] If the target working condition is that the lateral acceleration of the vehicle changes, determine each weight coefficient in the sliding mode surface based on the current lateral acceleration;

[0147] If the target working condition is that the steering wheel angle and the change rate of the steering wheel angle change, determine each weight coefficient in the sliding mode surface based on the current steering wheel angle and the change rate of the steering wheel angle;

[0148] If the target working condition is that the speed of the vehicle changes, determine each weight coefficient in the sliding mode surface based on the current speed of the vehicle;

[0149] If the target working condition is that the magnitude of the vehicle stability factor changes, determine each weight coefficient in the sliding mode surface based on the comparison result between the stability factor and a preset value.

[0150] In a possible embodiment, if the lateral acceleration changes, the weight coefficient of the yaw rate deviation changes in direct proportion to the lateral acceleration, and within the first range of the change in the lateral acceleration, the weight coefficient of the yaw rate change rate deviation changes in direct proportion to the lateral acceleration, and within the second range of the change in the lateral acceleration, the weight coefficient of the yaw rate change rate deviation remains unchanged;

[0151] If the speed of the vehicle changes, the weight coefficient of the yaw rate deviation changes in direct proportion to the speed of the vehicle, and within the first range of the change in the speed of the vehicle, the weight coefficient of the sideslip angle deviation of the center of mass changes in direct proportion to the speed of the vehicle, and within the second range of the change in the speed of the vehicle, the weight coefficient of the sideslip angle deviation of the center of mass remains unchanged;

[0152] If the magnitude of the stability factor of the vehicle changes, the weight coefficient of the yaw rate deviation changes inversely with the stability factor of the vehicle.

[0153] In a possible embodiment, the weight coefficient adjustment module 440 is specifically configured to:

[0154] Based on the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the weight coefficient of the yaw rate change rate corresponding to each individual condition included in the target condition, respectively, determine the weight coefficient of the yaw rate deviation, the weight coefficient of the sideslip angle deviation of the center of mass, and the weight coefficient of the yaw rate change rate corresponding to the target condition.

[0155] In a possible embodiment, based on the weight coefficients of the yaw rate deviation, the sideslip angle deviation of the center of mass, and the weight coefficient of the yaw rate change rate corresponding to each individual condition included in the target condition, respectively, determining the weight coefficient of the yaw rate deviation, the weight coefficient of the sideslip angle deviation of the center of mass, and the weight coefficient of the yaw rate change rate corresponding to the target condition includes:

[0156] Sum and normalize the weight coefficients of the yaw rate deviation corresponding to each individual condition included in the target condition to obtain the weight coefficient of the yaw rate deviation corresponding to the target condition;

[0157] Sum and normalize the weight coefficients of the sideslip angle deviation of the center of mass corresponding to each individual condition included in the target condition to obtain the weight coefficient of the sideslip angle deviation of the center of mass corresponding to the target condition;

[0158] Sum and normalize the weight coefficients of the yaw rate change rate deviation corresponding to each condition included in the target condition to obtain the weight coefficient of the yaw rate change rate deviation corresponding to the target condition.

[0159] The technical solution provided by the embodiments of the present application can select a sliding mode surface through the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation of the vehicle, so that the yaw rate of the vehicle approaches the desired angular velocity, the sideslip angle of the vehicle center of mass approaches the desired sideslip angle of the center of mass, and the yaw rate change rate of the vehicle approaches the desired angular velocity change rate, which can effectively avoid the situation of vehicle yaw and instability; determine the working conditions during the current vehicle driving process through the road surface adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information, the vehicle speed, and the stability factor, and adjust the weight coefficients in the sliding mode surface through the working conditions, which can adapt to different working conditions, has stronger environmental adaptability, makes the vehicle control more stable, and can better respond to the driver's intention and maintain the handling and stability of the vehicle.

[0160] As Figure 5 shown, an embodiment of the present application provides an electronic device, including a processor 111, a communication interface 112, a memory 113, and a communication bus 114. Among them, the processor 111, the communication interface 112, and the memory 113 complete mutual communication through the communication bus 114.

[0161] The memory 113 is used to store a computer program.

[0162] In an embodiment of the present application, when the processor 111 executes the program stored on the memory 113, it implements the distributed drive control method based on sliding mode control provided by any one of the foregoing method embodiments, including:

[0163] Establish a three-degree-of-freedom model of the vehicle.

[0164] Perform weighted combination on the yaw rate deviation, the sideslip angle deviation of the center of mass, and the yaw rate change rate deviation of the vehicle, and select a sliding mode surface of the sliding mode control.

[0165] Determine the target working condition during the vehicle driving process based on at least one of the road surface adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information of the vehicle, the speed of the vehicle, and the stability factor of the vehicle.

[0166] Adjust the weight coefficient of the yaw rate deviation, the weight coefficient of the sideslip angle deviation of the center of mass, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target working condition to obtain a sliding mode surface corresponding to the target working condition.

[0167] Determine the control function of the sliding mode control based on the sliding mode surface corresponding to the target working condition, the three-degree-of-freedom model, and the reaching law function of the sliding mode control, and control the vehicle based on the control function.

[0168] An embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps of the distributed drive control method based on sliding mode control provided by any one of the foregoing method embodiments.

[0169] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0170] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the relevant technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0171] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, as used herein, the singular forms "a", "an", and "the" may also include the plural forms. The terms "comprising", "including", "containing", and "having" are inclusive and thus specify the presence of the stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the particular order described or illustrated, unless the order of performance is explicitly stated. It should also be understood that additional or alternative steps may be used.

[0172] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A distributed drive control method based on sliding mode control, characterized in that: include: Establish a three-degree-of-freedom model of the vehicle; Performing a weighted combination of the vehicle's yaw rate deviation, center of mass sideslip angle deviation, and yaw rate change rate deviation to select a sliding mode surface for sliding mode control; Determining a target operating condition during driving of the vehicle based on at least one of a road adhesion coefficient, a lateral acceleration of the vehicle, steering wheel information of the vehicle, a speed of the vehicle, and a stability factor of the vehicle; adjusting the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target operating condition to obtain the sliding mode surface corresponding to the target operating condition; A control function of the sliding mode control is determined based on the sliding mode surface corresponding to the target operating condition, the three-degree-of-freedom model, and a reaching rate function of the sliding mode control, and the vehicle is controlled based on the control function.

2. The method according to claim 1, characterized in that The step of weighting and combining the yaw rate deviation, the center of mass sideslip angle deviation and the yaw rate change rate deviation of the vehicle to select a sliding mode surface for sliding mode control comprises: The sliding surface of the sliding mode control is selected based on the following formula: Where S is the switching function of the sliding surface; (ω-ω xd ) is the yaw rate deviation of the vehicle; ω is the vehicle yaw rate; ω xd is the desired yaw rate; ξ1 is the weight coefficient of the yaw rate deviation; Among them, (β-β xd ) is the center of mass sideslip angle deviation of the vehicle; β is the center of mass sideslip angle of the vehicle, β xd is the desired center of mass sideslip angle; ξ2 is the weight coefficient of the center of mass sideslip angle deviation; in, is the yaw rate change rate deviation of the vehicle; is the rate of change of the vehicle's yaw rate, is the expected yaw rate change rate; ξ3 is the weight coefficient of the yaw rate change rate deviation.

3. The method according to claim 1, characterized in that: The determining of the target operating condition during the driving of the vehicle based on at least one of the road adhesion coefficient, the lateral acceleration of the vehicle, the steering wheel information of the vehicle, the speed of the vehicle, and the stability factor of the vehicle includes: During vehicle driving, if one of the following operating conditions occurs, the target operating condition is a single operating condition; if at least two of the following operating conditions occur, the target operating condition is a composite operating condition: The road adhesion coefficient and the rate of change of the road adhesion coefficient change; The vehicle's lateral acceleration changes; Changes in steering wheel angle and steering wheel angle change rate; The speed of the vehicle changes; The vehicle's stability factor changes in size.

4. The method according to claim 3, characterized in that If the target operating condition is a separate operating condition, the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface are adjusted based on the target operating condition, including: If the target working condition is that the road adhesion coefficient and the road adhesion coefficient change rate change, determine each weight coefficient in the sliding surface based on the current road adhesion coefficient and the road adhesion coefficient change rate; If the target operating condition is a change in the lateral acceleration of the vehicle, determining each weight coefficient in the sliding mode surface based on the current lateral acceleration; If the target working condition is a change in the steering wheel angle and the steering wheel angle change rate, determining each weight coefficient in the sliding surface based on the current steering wheel angle and the steering wheel angle change rate; If the target operating condition is a change in the speed of the vehicle, determining each weight coefficient in the sliding surface based on the current speed of the vehicle; If the target operating condition is that the stability factor of the vehicle changes, each weight coefficient in the sliding surface is determined based on a comparison result between the stability factor and a preset value.

5. The method according to claim 4, characterized in that If the lateral acceleration changes, the weight coefficient of the yaw rate deviation changes in proportion to the lateral acceleration, and within a first range of the lateral acceleration change, the weight coefficient of the yaw rate change rate deviation changes in proportion to the lateral acceleration, and within a second range of the lateral acceleration change, the weight coefficient of the yaw rate change rate deviation remains unchanged; If the speed of the vehicle changes, the weight coefficient of the yaw rate deviation changes in proportion to the speed of the vehicle, and within a first range of speed changes of the vehicle, the weight coefficient of the center of mass sideslip angle deviation changes in proportion to the speed of the vehicle, and within a second range of speed changes of the vehicle, the weight coefficient of the center of mass sideslip angle deviation remains unchanged; If the magnitude of the stability factor of the vehicle changes, the weight coefficient of the yaw rate deviation changes inversely proportional to the stability factor of the vehicle.

6. The method according to claim 3, characterized in that If the target operating condition is a composite operating condition, the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation, and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface are adjusted based on the target operating condition, including: Based on the weight coefficients of the yaw rate deviation, the weight coefficients of the center of mass sideslip angle deviation and the weight coefficients of the yaw rate change rate deviation corresponding to each individual operating condition included in the target operating condition, the weight coefficients of the yaw rate deviation, the weight coefficients of the center of mass sideslip angle deviation and the weight coefficients of the yaw rate change rate deviation corresponding to the target operating condition are determined accordingly.

7. The method according to claim 6, characterized in that Based on the weight coefficients of the yaw rate deviation, the weight coefficients of the center of mass sideslip angle deviation and the weight coefficients of the yaw rate change rate deviation respectively corresponding to each individual operating condition included in the target operating condition, the weight coefficients of the yaw rate deviation, the weight coefficients of the center of mass sideslip angle deviation and the weight coefficients of the yaw rate change rate deviation corresponding to the target operating condition are determined accordingly, including: The weight coefficients of the yaw rate deviations corresponding to the individual operating conditions included in the target operating condition are summed and normalized to obtain the weight coefficient of the yaw rate deviation corresponding to the target operating condition; The weight coefficients of the center of mass sideslip angle deviation corresponding to each individual working condition included in the target working condition are summed and normalized to obtain the weight coefficient of the center of mass sideslip angle deviation corresponding to the target working condition; The weight coefficients of the yaw rate change rate deviation corresponding to each operating condition included in the target operating condition are summed and normalized to obtain the weight coefficient of the yaw rate change rate deviation corresponding to the target operating condition.

8. A distributed drive control device based on sliding mode control, characterized in that: include: Model building module, used to build a three-degree-of-freedom model of the vehicle; A sliding surface selection module is used to weight the vehicle's yaw rate deviation, center of mass sideslip angle deviation, and yaw rate change rate deviation to select a sliding surface for sliding mode control; a working condition determination module, configured to determine a target working condition during driving of the vehicle based on at least one of a road adhesion coefficient, a lateral acceleration of the vehicle, steering wheel information of the vehicle, a speed of the vehicle, and a stability factor of the vehicle; a weight coefficient adjustment module, configured to adjust the weight coefficient of the yaw rate deviation, the weight coefficient of the center of mass sideslip angle deviation and the weight coefficient of the yaw rate change rate deviation in the sliding mode surface based on the target working condition, so as to obtain a target sliding mode surface corresponding to the target working condition; A control module is used to determine a control function of the sliding mode control based on the target sliding mode surface, the three-degree-of-freedom model and a reaching rate function of the sliding mode control, and control the vehicle based on the control function.

9. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to execute a computer program stored in the memory, and when the computer program is executed, implement the method described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method described in any one of claims 1 to 7 is implemented.

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