Vehicle energy-saving and stable coordinated control method, device, driving computer and storage medium based on phase plane

Abstract

The present invention provides a vehicle energy-saving stability coordinated control method, device, driving computer and storage medium based on phase plane, which relates to the field of vehicle control. The method judges the stability of the vehicle according to the vehicle's center of mass sideslip angle-center of mass sideslip angular velocity. When the vehicle is within the stable area, the vehicle's torque distribution is controlled by the energy-saving torque distributor, and the control target is to minimize the motor energy loss; when the vehicle state is outside the stable area, the vehicle's torque distribution is controlled by the yaw torque controller to generate a suitable additional yaw torque and minimize tire utilization to maintain vehicle stability; when the vehicle state moves from the stable area to the unstable area, and the vehicle state exceeds the stable boundary line, the torque distribution becomes the yaw torque controller control; when the vehicle state moves from the unstable area to the stable area, and the vehicle state enters the energy-saving boundary line, the torque distribution becomes the energy-saving torque distributor control.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control, and in particular to a vehicle energy-saving and stable coordinated control method, device, driving computer and storage medium based on a phase plane. Background Art

[0002] With the rapid development of the automotive industry and the continuous improvement of people's environmental awareness, people not only have higher and higher requirements for the safe and stable operation of vehicles, but also have higher requirements for the energy-saving effect of vehicles. However, during the operation of the vehicle, it is often difficult to take into account the energy saving and handling stability of the vehicle at the same time. With the vigorous development of four-wheel independent drive electric vehicles, the torque distribution between wheels has been decoupled. How to control the torque of each wheel to achieve the best energy-saving effect and maintain good handling stability has good prospects. Therefore, it is particularly important to propose a strategy that can coordinate control between energy saving and handling stability. Summary of the invention

[0003] Purpose of the invention: To propose a vehicle energy-saving and stable coordinated control method, device, on-board computer and storage medium based on phase plane to solve the above-mentioned problems existing in the prior art.

[0004] First, a vehicle energy-saving and stable coordinated control method based on a phase plane is proposed, and the steps are as follows:

[0005] S1. Using the sideslip angle and yaw rate as state variables, a two-degree-of-freedom model of the vehicle is established, wherein the two-degree-of-freedom model of the vehicle reflects the current state of the vehicle;

[0006] S2, inputting the current vehicle speed and the current front wheel turning angle, obtaining a center of mass sideslip angle-center of mass sideslip angular velocity phase plane, and determining a stable region, an unstable region and an energy-saving region of the phase plane, wherein the energy-saving region is located within the stable region;

[0007] S3. The driving computer calculates the vehicle state at the last moment and determines the area where the vehicle state at the last moment is located:

[0008] If it is located in the energy-saving area, jump to step S5;

[0009] Otherwise, jump to step S4;

[0010] S4. The driving computer determines whether the current vehicle state is within the stable area:

[0011] If yes, go to step S6;

[0012] If not, feedback is given to the yaw moment controller and the process goes to step S7;

[0013] S5. The driving computer determines whether the current vehicle state is within the stable area:

[0014] If yes, it is fed back to the energy-saving torque distributor and the process goes to step S7;

[0015] If not, feedback is given to the yaw moment controller and the process goes to step S8;

[0016] S6. The on-board computer determines whether the vehicle yaw moment controller is turned on at the current moment:

[0017] If yes, then feedback is given to the yaw moment controller and the process goes to step S8;

[0018] If not, the information is fed back to the energy-saving torque distributor and the process goes to step S7;

[0019] S7, the energy-saving torque distributor obtains an optimal torque distribution coefficient according to the current motor speed, and distributes the driver's required torque to each wheel according to the optimal torque distribution coefficient;

[0020] S8. The yaw moment controller calculates an additional yaw moment, and distributes the driver's required torque to each wheel according to the additional yaw moment.

[0021] In a further embodiment of the first aspect, the vehicle two-degree-of-freedom model expression in step S1 is as follows:

[0022]

[0023] In the formula, Indicates the front wheel turning angle; represents the yaw angular velocity; represents the sideslip angle of the center of mass; represents the yaw angular acceleration; represents the sideslip angular velocity of the center of mass; Indicates vehicle speed; represents the distance from the vehicle's center of mass to the front axle, Indicates the distance from the vehicle's center of mass to the rear axle; Indicates the front axle cornering stiffness; represents the rear axle lateral stiffness; m represents the vehicle body mass; Represents the vehicle's moment of inertia around the Z axis.

[0024] In a further embodiment of the first aspect, step S2 further comprises:

[0025] S2-1, according to the longitudinal speed measured by the vehicle sensor and lateral speed , calculate the center of mass sideslip angle :

[0026]

[0027] Based on the center of mass sideslip angle , substituting into the vehicle two-degree-of-freedom model expression, the center of mass sideslip angular velocity is obtained ;

[0028] S2-2. Determine the stable boundary line and energy-saving boundary line of the center of mass sideslip angle-center of mass sideslip angular velocity phase plane:

[0029] The mathematical model of the stable boundary line is:

[0030]

[0031] Where A is the slope of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces; B is the intercept of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces;

[0032] The mathematical model of the energy-saving boundary line is:

[0033]

[0034] Where, C is the slope of the energy-saving boundary line, and C=A; D is the intercept of the energy-saving boundary line, D=0.6*B;

[0035] S2-3. Based on the stable boundary line and the energy-saving boundary line, the area surrounded by the two stable boundary lines is a stable area, and the area surrounded by the two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stable area.

[0036] In a further embodiment of the first aspect, the vehicle energy-saving and stable coordinated control method implements the following strategy:

[0037] When the vehicle is within the energy-saving area, the torque distribution of the vehicle is controlled by the energy-saving torque distributor, and the control goal is to minimize the energy loss of the motor;

[0038] When the vehicle state is outside the stable region, the vehicle torque distribution is controlled by the yaw moment controller to generate appropriate additional yaw moment and minimize tire utilization to maintain vehicle stability;

[0039] When the vehicle state moves from the energy-saving area to the stable area, and the vehicle state does not exceed the stable boundary line, the torque distribution is still controlled to minimize the motor energy loss;

[0040] When the vehicle state moves from the stable region to the unstable region and the vehicle state exceeds the stable boundary line, the torque distribution changes to the yaw torque controller control;

[0041] When the vehicle state moves from the unstable area to the stable area, and the vehicle state does not enter the energy-saving boundary line, the torque distribution is still controlled by the yaw torque controller;

[0042] When the vehicle state moves from the unstable region to the stable region and the vehicle state enters within the energy-saving boundary line, the torque distribution changes to the energy-saving torque distributor control.

[0043] In a further embodiment of the first aspect, step S7 further comprises:

[0044] The energy-saving torque distributor minimizes the motor energy loss according to the motor efficiency map To optimize the target, the optimal torque distribution coefficient under different speeds and torques is obtained:

[0045]

[0046] In the formula, Indicates the wheel index, 1 indicates the left front wheel, 2 indicates the right front wheel, 3 indicates the left rear wheel, and 4 indicates the right rear wheel; represents the motor power on the i-th wheel; is the i-th wheel speed, Expressed as the driving torque of each wheel hub motor, including the left front wheel torque , right front wheel torque , left rear wheel torque , right rear wheel torque ; represents the efficiency of a single wheel motor, obtained from the motor efficiency diagram; It means minimizing the power of the four wheel motors;

[0047] At this time, the torque distributed to the four wheels is as follows:

[0048]

[0049] In the formula, , , , are the torque distribution coefficients of the four wheels respectively, ; Indicates the driver's demand torque.

[0050] In a further embodiment of the first aspect, the additional yaw moment in step S8 The expression is as follows:

[0051]

[0052] In the formula, Represents the vehicle's moment of inertia around the Z axis; Represents the rear axle cornering stiffness; Indicates the front axle cornering stiffness; The derivative of the difference between the actual center of mass sideslip angle and the ideal center of mass sideslip angle; The derivative representing the difference between the actual yaw rate and the ideal yaw rate; represents the reaching law constant; represents a symbolic function; Represents the relative weight coefficient between the error and the error change rate.

[0053] In a further embodiment of the first aspect, the yaw moment controller obtains the additional yaw moment After the driver's required torque T is calculated, the actual output torque of the four wheels is calculated as follows:

[0054] The optimization goal is to minimize tire utilization. Since the wheel hub motor can only control the longitudinal force, the objective function is constructed. :

[0055]

[0056] In the formula, The longitudinal driving force of the wheel hub motor of each wheel, is the road adhesion coefficient of each wheel, is the vertical load of each wheel;

[0057] The longitudinal driving force of each wheel hub motor ;

[0058] Provides torque for each wheel hub motor, including the left front wheel torque , right front wheel torque , left rear wheel torque , right rear wheel torque ; r represents the rolling radius of the wheel;

[0059] At this time, the torque distributed to the four wheels is as follows:

[0060]

[0061] Where, T represents the driver's required torque; represents the additional yaw moment; r represents the wheel rolling radius; Bw represents the wheel track; Indicates the road adhesion coefficient of the left rear wheel; Indicates the road adhesion coefficient of the right rear wheel; Indicates the vertical load on the left rear wheel; Indicates the vertical load on the right rear wheel; Indicates the vertical load on the left front wheel; Indicates the vertical load on the right front wheel.

[0062] According to a second aspect of the present invention, a vehicle energy-saving stability coordination control device is provided, which includes an energy-saving torque distributor, a yaw torque controller, and an energy-saving stability coordination controller.

[0063] The energy-saving stability coordination controller is used to construct a center of mass sideslip angle-center of mass sideslip angular velocity phase plane, and determine a stable boundary line and an energy-saving boundary line of the phase plane; based on the stable boundary line and the energy-saving boundary line, the area surrounded by two stable boundary lines is a stable area, and the area surrounded by two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stable area.

[0064] When the vehicle is within the energy-saving area, the torque distribution of the vehicle is controlled by the energy-saving torque distributor, and at this time, minimizing the energy loss of the motor is the control goal;

[0065] When the vehicle state is outside the stable region, the torque distribution of the vehicle is controlled by the yaw moment controller to generate a suitable additional yaw moment and minimize tire utilization to maintain vehicle stability;

[0066] When the vehicle state moves from the energy-saving area to the stable area, and the vehicle state does not exceed the stable boundary line, the torque distribution is still controlled to minimize the motor energy loss;

[0067] When the vehicle state moves from the stable region to the unstable region and the vehicle state exceeds the stable boundary line, the torque distribution changes to the yaw torque controller control;

[0068] When the vehicle state moves from the unstable region to the stable region and the vehicle state does not enter the energy-saving boundary line, the torque distribution is still controlled by the yaw torque controller;

[0069] When the vehicle state moves from the unstable region to the stable region and the vehicle state enters within the energy-saving boundary line, the torque distribution changes to the energy-saving torque distributor control.

[0070] According to the third aspect of the present invention, a driving computer is proposed, which includes a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, it implements the vehicle energy-saving and stability coordinated control method based on the phase plane as disclosed in the first aspect and its further embodiments.

[0071] The fourth aspect of the present invention proposes a computer-readable storage medium, which stores at least one executable instruction. When the executable instruction is run on an electronic device, the electronic device executes the vehicle energy-saving and stability coordinated control method based on the phase plane as disclosed in the first aspect and its further embodiments.

[0072] Beneficial effects: The present invention provides a vehicle energy-saving and stable coordinated control method, device, driving computer and storage medium based on the phase plane. Through the above control strategy, the vehicle can switch the torque control strategy in real time during driving, while maintaining the stability of the vehicle and improving the energy utilization efficiency, so as to achieve a control effect that takes into account both vehicle stability and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a flow chart of a vehicle energy-saving and stable coordinated control method in an embodiment of the present invention.

[0074] Figure 2 It is a structural diagram of the vehicle energy-saving and stability coordinated control device in an embodiment of the present invention.

[0075] Figure 3 Schematic diagram of the center of mass sideslip angle-center of mass sideslip angular velocity phase plane in an embodiment of the present invention. DETAILED DESCRIPTION

[0076] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

[0077] Embodiment 1:

[0078] The present embodiment discloses a vehicle energy-saving stability coordinated control method based on a phase plane. Generally speaking, the present method determines the stability of the vehicle according to the vehicle's center of mass sideslip angle-center of mass sideslip angular velocity. When the vehicle is within the energy-saving area, the torque distribution of the vehicle is controlled by the energy-saving torque distributor, and the control target is to minimize the motor energy loss at this time; when the vehicle state is outside the stable area, the torque distribution of the vehicle is controlled by the yaw torque controller to generate a suitable additional yaw torque and minimize the tire utilization to maintain the stability of the vehicle; when the vehicle state moves from the energy-saving area to the stable area, and the vehicle state does not exceed the stable boundary line, the torque distribution is still controlled by minimizing the motor energy loss; when the vehicle state moves from the stable area to the unstable area, and the vehicle state exceeds the stable boundary line, the torque distribution becomes controlled by the yaw torque controller; when the vehicle state moves from the unstable area to the stable area, and the vehicle state does not enter the energy-saving boundary line, the torque distribution is still controlled by the yaw torque controller; when the vehicle state moves from the unstable area to the stable area, and the vehicle state enters the energy-saving boundary line, the torque distribution becomes controlled by the energy-saving torque distributor.

[0079] Embodiment 2:

[0080] To implement the method disclosed in the above embodiment 1, this embodiment discloses specific steps, see Figure 1 As shown:

[0081] Step 1: Using the sideslip angle and yaw rate as state variables, a two-degree-of-freedom model of the vehicle is established, and the two-degree-of-freedom model of the vehicle reflects the current state of the vehicle.

[0082] The mathematical expression of the vehicle two-degree-of-freedom model is as follows:

[0083]

[0084] In the formula, Indicates the front wheel turning angle; represents the yaw angular velocity; represents the sideslip angle of the center of mass; represents the yaw angular acceleration; represents the sideslip angular velocity of the center of mass; Indicates vehicle speed; represents the distance from the vehicle's center of mass to the front axle, Indicates the distance from the vehicle's center of mass to the rear axle; Indicates the front axle cornering stiffness; represents the rear axle lateral stiffness; m represents the vehicle body mass; Represents the vehicle's moment of inertia around the Z axis.

[0085] Step 2: input the current vehicle speed and the current front wheel turning angle, obtain the center of mass sideslip angle-center of mass sideslip angular velocity phase plane, and determine the stable region, unstable region and energy-saving region of the phase plane, wherein the energy-saving region is located within the stable region. The specific process is as follows:

[0086] First, according to the longitudinal speed measured by the vehicle sensor and lateral speed , calculate the center of mass sideslip angle :

[0087]

[0088] Based on the center of mass sideslip angle , substituting into the vehicle two-degree-of-freedom model expression, the center of mass sideslip angular velocity is obtained ;

[0089] Then determine the stable boundary line and energy-saving boundary line of the center of mass sideslip angle-center of mass sideslip angular velocity phase plane:

[0090] The mathematical model of the stable boundary line is:

[0091]

[0092] Where A is the slope of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces; B is the intercept of the stable boundary line, such as Figure 3 Indicated by the dashed line;

[0093] Adhesion coefficient of different road surfaces The phase plane stability boundary parameters are shown in Table 1.

[0094] Table 1: Adhesion coefficients of different road surfaces Phase plane stability boundary parameter table

[0095]

[0096] The mathematical model of the energy-saving boundary line is:

[0097]

[0098] In the formula, C is the slope of the energy-saving boundary line, and C=A; D is the intercept of the energy-saving boundary line, D=0.6*B, such as Figure 3 Shown by the solid line.

[0099] Based on the stable boundary line and the energy-saving boundary line, the area surrounded by the two stable boundary lines is a stable area, and the area surrounded by the two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stable area.

[0100] Step 3, the on-board computer calculates the vehicle status at the last moment and determines the area where the vehicle status at the last moment is located: if it is located in the energy-saving area, jump to step 5; otherwise, jump to step 4.

[0101] Step 4: The on-board computer determines whether the current vehicle state is within the stable region. If so, proceed to step 6; if not, feedback is given to the yaw torque controller and proceed to step 7.

[0102] Step 5. The on-board computer determines whether the current vehicle state is within the stable area. If so, it is fed back to the energy-saving torque distributor and the process goes to step 7. If not, it is fed back to the yaw torque controller and the process goes to step 8.

[0103] Step 6: The on-board computer determines whether the vehicle yaw torque controller is turned on at the current moment: if so, it is fed back to the yaw torque controller and the process goes to step 8; if not, it is fed back to the energy-saving torque distributor and the process goes to step 7.

[0104] Step 7: The energy-saving torque distributor obtains an optimal torque distribution coefficient according to the current motor speed, and distributes the driver's required torque to each wheel according to the optimal torque distribution coefficient.

[0105] Specifically, the working strategy of the energy-saving torque distributor is as follows:

[0106] Energy-saving torque distributor according to motor efficiency map to minimize motor energy loss To optimize the target, the optimal torque distribution coefficient under different speeds and torques is obtained:

[0107]

[0108] In the formula, Indicates the wheel index, 1 indicates the left front wheel, 2 indicates the right front wheel, 3 indicates the left rear wheel, and 4 indicates the right rear wheel; is the i-th wheel speed, Expressed as the driving torque of each wheel hub motor, including the left front wheel torque , right front wheel torque , left rear wheel torque , right rear wheel torque ; Indicates the power of a single wheel motor; represents the efficiency of a single wheel motor, obtained from the motor efficiency diagram; represents minimizing the power of the four wheel motors.

[0109] At this time, the torque distributed to the four wheels is as follows:

[0110]

[0111] In the formula, , , , are the torque distribution coefficients of the four wheels respectively, ; Indicates the driver's demand torque.

[0112] Step 8: The yaw moment controller calculates an additional yaw moment, and distributes the driver's required torque to each wheel according to the additional yaw moment.

[0113] The working strategy of the yaw moment controller is as follows:

[0114] Since the four motors of the distributed drive electric vehicle are independently controllable, additional yaw torque can be generated through torque vector distribution, and the two-degree-of-freedom model differential equation can be written as:

[0115]

[0116] In the formula, Indicates the front wheel turning angle; represents the yaw angular velocity; represents the sideslip angle of the center of mass; represents the yaw angular acceleration; represents the sideslip angular velocity of the center of mass; Indicates vehicle speed; represents the distance from the vehicle's center of mass to the front axle, Indicates the distance from the vehicle's center of mass to the rear axle; Indicates the front axle cornering stiffness; represents the rear axle lateral stiffness; m represents the vehicle body mass; Represents the vehicle's moment of inertia around the Z axis; represents the additional yaw moment.

[0117] The additional yaw moment is:

[0118]

[0119] In the formula, Represents the vehicle's moment of inertia around the Z axis; Represents the rear axle cornering stiffness; Indicates the front axle cornering stiffness; The derivative of the difference between the actual center of mass sideslip angle and the ideal center of mass sideslip angle; The derivative representing the difference between the actual yaw rate and the ideal yaw rate; represents the convergence law constant, which indicates the rate at which the state point of the system approaches the sliding surface; represents a symbolic function; Represents the relative weight coefficient between the error and the error change rate.

[0120] The yaw moment controller obtains the additional yaw moment After the driver's required torque T is calculated, the actual output torque of the four wheels is calculated as follows:

[0121] The optimization goal is to minimize tire utilization. Since the wheel hub motor can only control the longitudinal force, the objective function is constructed. :

[0122]

[0123] In the formula, The longitudinal driving force of the wheel hub motor of each wheel, is the road adhesion coefficient of each wheel, is the vertical load of each wheel;

[0124] The longitudinal driving force of each wheel hub motor ;

[0125] Provides torque for each wheel hub motor, including the left front wheel torque , right front wheel torque , left rear wheel torque , right rear wheel torque ; r represents the rolling radius of the wheel;

[0126] At this time, the torque distributed to the four wheels is as follows:

[0127]

[0128] Where, T represents the driver's required torque; represents the additional yaw moment; r represents the wheel rolling radius; Bw represents the wheel track; Indicates the road adhesion coefficient of the left rear wheel; Indicates the road adhesion coefficient of the right rear wheel; Indicates the vertical load on the left rear wheel; Indicates the vertical load on the right rear wheel; Indicates the vertical load on the left front wheel; Indicates the vertical load on the right front wheel.

[0129] Embodiment 3:

[0130] This embodiment discloses a vehicle energy-saving and stable coordinated control device. Figure 2 The device includes an energy-saving torque distributor, a yaw torque controller, and an energy-saving stability coordination controller.

[0131] The energy-saving stability coordination controller is used to construct a center of mass sideslip angle-center of mass sideslip angular velocity phase plane, and determine the stability boundary line and energy-saving boundary line of the phase plane; based on the stability boundary line and the energy-saving boundary line, the area surrounded by two stability boundary lines is a stable area, and the area surrounded by two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stability area; when the vehicle is within the energy-saving area, the torque distribution of the vehicle is controlled by the energy-saving torque distributor, and at this time, minimizing the energy loss of the motor is the control goal; when the vehicle state is outside the stable area, the torque distribution of the vehicle is controlled by the yaw torque controller to generate a suitable additional yaw torque and minimum The tire utilization rate is optimized to maintain vehicle stability; when the vehicle state moves from the energy-saving area to the stable area, and the vehicle state does not exceed the stable boundary line, the torque distribution is still controlled by minimizing the motor energy loss; when the vehicle state moves from the stable area to the unstable area, and the vehicle state exceeds the stable boundary line, the torque distribution is changed to be controlled by the yaw torque controller; when the vehicle state moves from the unstable area to the stable area, and the vehicle state does not enter the energy-saving boundary line, the torque distribution is still controlled by the yaw torque controller; when the vehicle state moves from the unstable area to the stable area, and the vehicle state enters the energy-saving boundary line, the torque distribution is changed to be controlled by the energy-saving torque distributor.

[0132] Embodiment 4:

[0133] The present embodiment discloses a driving computer ECU, which includes a processor, a memory, a communication interface and a communication bus. The processor, the memory and the communication interface communicate with each other through the communication bus. The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute the vehicle energy-saving stability coordinated control method disclosed in the above embodiment. The electronic device can also communicate with one or more external devices (such as keyboards, pointing devices, Bluetooth devices, etc.), and can also communicate with one or more devices that enable users to interact with the electronic device, and / or communicate with any device that enables the electronic device to communicate with one or more other computing devices (such as routers, modems, etc.). This communication can be carried out through an input / output (I / O) interface. In addition, the electronic device can also communicate with one or more networks (such as local area networks (LANs), wide area networks (WANs) and / or public networks, such as the Internet) through a network adapter. The network adapter communicates with other modules of the electronic device through a bus. It should be understood that although not shown in the figures, other hardware and / or software modules may be used in conjunction with the electronic device, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0134] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0136] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0137] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0138] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0139] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0140] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0141] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A vehicle energy-saving and stable coordinated control method based on phase plane, characterized in that: The steps include: S1: Using the sideslip angle and yaw rate as state variables, a two-degree-of-freedom model of the vehicle is established, wherein the two-degree-of-freedom model of the vehicle reflects the current state of the vehicle; S2: inputting the current vehicle speed and the current front wheel turning angle, obtaining a center of mass sideslip angle-center of mass sideslip angular velocity phase plane, and determining a stable region, an unstable region and an energy-saving region of the phase plane, wherein the energy-saving region is located within the stable region; S2-1: Longitudinal vehicle speed measured by vehicle sensors and lateral speed , calculate the center of mass sideslip angle : ； Based on the center of mass sideslip angle , substituting into the vehicle two-degree-of-freedom model expression, the center of mass sideslip angular velocity is obtained ; S2-2: Determine the stability boundary line and energy-saving boundary line of the center of mass sideslip angle-center of mass sideslip angular velocity phase plane: The mathematical model of the stable boundary line is: ； Where A is the slope of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces; B is the intercept of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces; The mathematical model of the energy-saving boundary line is: ； Where, C is the slope of the energy-saving boundary line, and C=A; D is the intercept of the energy-saving boundary line, D=0.6*B; S2-3: Based on the stable boundary line and the energy-saving boundary line, the area surrounded by the two stable boundary lines is a stable area, and the area surrounded by the two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stable area; S3: The driving computer calculates the vehicle state at the last moment and determines the area where the vehicle state at the last moment is located: If it is in the energy-saving area, jump to step S5; Otherwise, jump to step S4; S4: The on-board computer determines whether the current vehicle state is within the stable area: If yes, go to step S6; If not, feedback is given to the yaw moment controller and the process goes to step S7; S5: The on-board computer determines whether the current vehicle state is within the stable area: If yes, it is fed back to the energy-saving torque distributor and the process goes to step S7; If not, feedback is given to the yaw moment controller and the process goes to step S8; S6: The on-board computer determines whether the vehicle yaw moment controller is turned on at the current moment: If yes, then feedback is given to the yaw moment controller and the process goes to step S8; If not, the information is fed back to the energy-saving torque distributor and the process goes to step S7; S7: the energy-saving torque distributor obtains an optimal torque distribution coefficient according to the current motor speed, and distributes the driver's required torque to each wheel according to the optimal torque distribution coefficient; S8: The yaw moment controller calculates an additional yaw moment, and distributes the driver's required torque to each wheel according to the additional yaw moment.

2. The vehicle energy-saving and stable coordinated control method based on the phase plane according to claim 1 is characterized in that: The vehicle two-degree-of-freedom model expression in step S1 is as follows: ； In the formula, Indicates the front wheel turning angle; represents the yaw angular velocity; represents the sideslip angle of the center of mass; represents the yaw angular acceleration; represents the sideslip angular velocity of the center of mass; Indicates the longitudinal vehicle speed; represents the distance from the vehicle's center of mass to the front axle, Indicates the distance from the vehicle's center of mass to the rear axle; Indicates the front axle cornering stiffness; represents the rear axle lateral stiffness; m represents the vehicle body mass; Represents the vehicle's moment of inertia around the Z axis.

3. The vehicle energy-saving and stable coordinated control method based on the phase plane according to claim 1 is characterized in that: When the vehicle is within the energy-saving area, the torque distribution of the vehicle is controlled by the energy-saving torque distributor, and the control goal is to minimize the energy loss of the motor; When the vehicle state is outside the stable region, the vehicle torque distribution is controlled by the yaw moment controller to generate appropriate additional yaw moment and minimize tire utilization to maintain vehicle stability; When the vehicle state moves from the energy-saving area to the stable area, and the vehicle state does not exceed the stable boundary line, the torque distribution is still controlled to minimize the motor energy loss; When the vehicle state moves from the stable region to the unstable region and the vehicle state exceeds the stable boundary line, the torque distribution changes to the yaw torque controller control; When the vehicle state moves from the unstable area to the stable area, and the vehicle state does not enter the energy-saving boundary line, the torque distribution is still controlled by the yaw torque controller; When the vehicle state moves from the unstable region to the stable region and the vehicle state enters within the energy-saving boundary line, the torque distribution changes to the energy-saving torque distributor control.

4. The vehicle energy-saving and stable coordinated control method based on the phase plane according to claim 2 is characterized in that: Step S7 further comprises: The energy-saving torque distributor minimizes the motor energy loss according to the motor efficiency map To optimize the target, the optimal torque distribution coefficient under different speeds and torques is obtained: ； In the formula, represents the motor power on the i-th wheel; is the i-th wheel speed, Expressed as the driving torque of each wheel hub motor, including the left front wheel torque , right front wheel torque , left rear wheel torque , right rear wheel torque ; represents the efficiency of a single wheel motor, obtained from the motor efficiency diagram; It means minimizing the power of the four wheel motors; At this time, the torque distributed to the four wheels is as follows: ； In the formula, , , , are the torque distribution coefficients of the four wheels respectively, ; Indicates the driver's demand torque.

5. The vehicle energy-saving and stable coordinated control method based on phase plane according to claim 2 is characterized in that: The additional yaw moment in step S8 The expression is as follows: ； In the formula, Represents the vehicle's moment of inertia around the Z axis; Represents the rear axle cornering stiffness; Indicates the front axle cornering stiffness; The derivative of the difference between the actual center of mass sideslip angle and the ideal center of mass sideslip angle; The derivative representing the difference between the actual yaw rate and the ideal yaw rate; represents the reaching law constant; represents a symbolic function; Represents the relative weight coefficient between the error and the error change rate.

6. The vehicle energy-saving and stable coordinated control method based on the phase plane according to claim 5 is characterized in that: The yaw moment controller obtains the additional yaw moment After the driver's required torque T is calculated, the actual output torque of the four wheels is calculated as follows: The optimization goal is to minimize tire utilization. Since the wheel hub motor can only control the longitudinal driving force, the objective function is constructed. : ； In the formula, The longitudinal driving force of the wheel hub motor of each wheel, is the road adhesion coefficient of each wheel, is the vertical load of each wheel; The longitudinal driving force of each wheel hub motor ; Provides torque for each wheel hub motor, including the left front wheel torque , right front wheel torque , left rear wheel torque , right rear wheel torque ; r represents the rolling radius of the wheel; At this time, the torque distributed to the four wheels is as follows: ； Where, T represents the driver's required torque; represents the additional yaw moment; r represents the wheel rolling radius; Bw represents the wheel track; Indicates the road adhesion coefficient of the left rear wheel; Indicates the road adhesion coefficient of the right rear wheel; Indicates the road adhesion coefficient of the left front wheel; Indicates the road adhesion coefficient of the right front wheel; Indicates the vertical load on the left rear wheel; Indicates the vertical load on the right rear wheel; Indicates the vertical load on the left front wheel; Indicates the vertical load on the right front wheel.

7. A vehicle energy-saving and stable coordinated control device, characterized in that: It includes energy-saving torque distributor, yaw torque controller, energy-saving stability coordination controller; The energy-saving stability coordination controller is used to construct a center of mass sideslip angle-center of mass sideslip angular velocity phase plane and determine a stable boundary line and an energy-saving boundary line of the phase plane, specifically including: Longitudinal vehicle speed measured by vehicle sensors and lateral speed , calculate the center of mass sideslip angle : ； Based on the center of mass sideslip angle , substituting into the vehicle two-degree-of-freedom model expression, the center of mass sideslip angular velocity is obtained ; Determine the stable boundary line and energy-saving boundary line of the center of mass sideslip angle-center of mass sideslip angular velocity phase plane: The mathematical model of the stable boundary line is: ； Where A is the slope of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces; B is the intercept of the stable boundary line, which is determined according to the adhesion coefficient of different road surfaces; The mathematical model of the energy-saving boundary line is: ； Where, C is the slope of the energy-saving boundary line, and C=A; D is the intercept of the energy-saving boundary line, D=0.6*B; Based on the stable boundary line and the energy-saving boundary line, the area surrounded by the two stable boundary lines is a stable area, and the area surrounded by the two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stable area; Based on the stable boundary line and the energy-saving boundary line, the area surrounded by the two stable boundary lines is a stable area, and the area surrounded by the two energy-saving boundary lines is an energy-saving area; the energy-saving area is included in the stable area; When the vehicle is within the energy-saving area, the torque distribution of the vehicle is controlled by the energy-saving torque distributor, and at this time, minimizing the energy loss of the motor is the control goal; When the vehicle state is outside the stable region, the torque distribution of the vehicle is controlled by the yaw moment controller to generate a suitable additional yaw moment and minimize tire utilization to maintain vehicle stability; When the vehicle state moves from the energy-saving area to the stable area, and the vehicle state does not exceed the stable boundary line, the torque distribution is still controlled to minimize the motor energy loss; When the vehicle state moves from the stable region to the unstable region and the vehicle state exceeds the stable boundary line, the torque distribution changes to the yaw torque controller control; When the vehicle state moves from the unstable region to the stable region and the vehicle state does not enter the energy-saving boundary line, the torque distribution is still controlled by the yaw torque controller; When the vehicle state moves from the unstable region to the stable region and the vehicle state enters within the energy-saving boundary line, the torque distribution changes to the energy-saving torque distributor control.

8. A driving computer, characterized in that: The on-board computer includes: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the vehicle energy-saving and stable coordinated control method based on the phase plane as described in any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that: The storage medium stores at least one executable instruction. When the executable instruction is executed on the electronic device, the electronic device executes the vehicle energy-saving and stability coordinated control method based on the phase plane as claimed in any one of claims 1 to 6.

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