Driving force control method and driving force control device

Abstract

A driving force control method. The driving force control method uses a front wheel motor (10f) connected to a front wheel (11f) of a vehicle (100) and a rear wheel motor (10r) connected to a rear wheel (11r) to control the front wheel driving force (F f ) and rear wheel drive force (F r ) performs a coordinated process of raising or lowering the vehicle body by coordinating the adjustment of at least one of the front wheel driving force and the rear wheel driving force and the application of the friction braking force to at least one of the front wheel and the rear wheel.

Description

Technical Field

[0001] The present invention relates to a driving force control method and a driving force control device. Background Art

[0002] In (Japan) JP2007-118898A, a braking-driving force control device has been proposed. When the suspension effect cannot be fully obtained in a hub motor type vehicle, the braking-driving force control device detects the pitch rate (pitch angular velocity) when passing through an uneven road surface, and provides different braking-driving forces to the front and rear wheels in a manner that reduces the detected pitch rate (displacement in the pitch direction). Summary of the invention

[0003] Depending on the driving scene of the vehicle, the vehicle body displacement (roll vibration) is sometimes large mainly in the up and down directions, and it is desirable to perform control to suppress the displacement. However, in the above-mentioned control of providing different braking and driving forces to the front and rear wheels to suppress the displacement in the pitch direction, there is a problem that the effect of suppressing the displacement in the up and down directions is limited.

[0004] Therefore, an object of the present invention is to provide a driving force control method and a driving force control device that can further improve the effect of suppressing the vertical displacement of a vehicle.

[0005] According to a certain aspect of the present invention, a driving force control method is provided, which uses a front wheel motor connected to the front wheel of a vehicle and a rear wheel motor connected to the rear wheel to control the front wheel driving force and the rear wheel driving force respectively. In the driving force control method, a coordinated process of adjusting the distribution of the front wheel driving force and the rear wheel driving force and the application of the friction braking force to at least one of the front wheel and the rear wheel is performed to raise or lower the vehicle body. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 The diagram is for explaining the configuration of a vehicle that executes a driving force control method according to an embodiment of the present invention.

[0007] Figure 2 This is a diagram showing an overview of the structure of a chassis system of a vehicle.

[0008] Figure 3 This is a diagram for explaining the effects of executing the coordination process.

[0009] Figure 4 This is a flowchart for explaining the driving force control method according to the present embodiment.

[0010] Figure 5 This is a timing chart showing an example of the time-series change of each control parameter when the control of the present embodiment is executed in a scene of traveling on a rough road.

[0011] Figure 6 This is a diagram for explaining the effects. DETAILED DESCRIPTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0013] Figure 1 The figure is a diagram for explaining the structure of a vehicle 100 that executes the driving force control method of this embodiment. It should be noted that the vehicle 100 of this embodiment is assumed to have a driving motor 10 as a driving source and to be able to travel using the driving force of the driving motor 10, such as an electric vehicle or a hybrid vehicle.

[0014] The drive motor 10 includes a front wheel motor 10f provided at the front position (front wheel side) of the vehicle 100 and driving the front wheel 11f, and a rear wheel motor 10r provided at the rear position (rear wheel side) and driving the rear wheel 11r.

[0015] The front wheel motor 10f is configured as a three-phase AC motor. When the front wheel motor 10f is in power operation, it receives power supply from a vehicle-mounted battery (not shown) to generate driving force. The driving force generated by the front wheel motor 10f is transmitted to the front wheel 11f via the front wheel transmission 16f and the front wheel drive shaft 21f. On the other hand, when the front wheel motor 10f is in regeneration, the regenerative braking force of the front wheel 11f is converted into AC power and supplied to the vehicle-mounted battery.

[0016] On the other hand, the rear wheel motor 10r is configured as a three-phase AC motor. When the rear wheel motor 10r is in power operation, it receives power supply from the vehicle-mounted battery to generate driving force. The driving force generated by the rear wheel motor 10r is transmitted to the rear wheel 11r via the rear wheel transmission 16r and the rear wheel drive shaft 21r. In addition, when the rear wheel motor 10r is in regeneration, the regenerative braking force of the rear wheel 11r is converted into AC power and supplied to the vehicle-mounted battery.

[0017] The inverter 12 includes a front wheel inverter 12f for adjusting the power supplied to the front wheel motor 10f (positive during power operation, negative during regeneration), and a rear wheel inverter 12r for adjusting the power supplied to the rear wheel motor 10r (positive during power operation, negative during regeneration).

[0018] The front wheel inverter 12f is used to realize the total driving force required by the vehicle 100 (hereinafter also referred to as the "total required driving force F fr ”) and determines the positive or negative driving force (hereinafter also referred to as “front wheel driving force F f”) to adjust the power supplied to the front wheel motor 10f. On the other hand, the rear wheel inverter 12r is used to achieve the total required driving force F fr The positive or negative driving force (hereinafter also referred to as the rear wheel driving force F r ”) adjusts the power supplied to the rear wheel motor 10r.

[0019] In particular, the sum of the driving forces equals the total demand driving force F fr The front wheel driving force F of this embodiment is determined in a consistent manner. f and rear wheel drive force F r It should be noted that the total demand driving force F fr For example, it is determined based on the amount of operation of an accelerator pedal mounted on vehicle 100 (accelerator opening), or a command from a predetermined automatic driving system (automatic driving control device) such as ADAS (Advanced Driver Assistance Systems) or AD (Autonomous Driving).

[0020] The brake actuator 14 is composed of a known mechanical brake operated by oil pressure or the like, and has the following functions: providing a friction braking force (hereinafter also referred to as "front wheel braking force B11f") to the front wheel 11f; f ”) and provides a friction braking force (hereinafter also referred to as “rear wheel braking force B ”) to the rear wheel 11r. r ”) of the rear wheel friction brake 14r.

[0021] In addition, the vehicle 100 is provided with a control system for controlling the front wheel driving force F f , rear wheel driving force F r , front wheel braking force B f , and rear wheel braking force B r The controller 50 serves as a driving force control device.

[0022] The controller 50 is composed of a computer having a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface), and is programmed to be able to perform various processes of vehicle control as described below. In particular, the functions of the controller 50 can be implemented by any on-board computer such as a vehicle controller (VCM: Vehicle Control Module), a vehicle motion control device (VMC: Vehicle Motion Controller), and a motor controller, and / or a computer installed outside the vehicle 100. It should be noted that the controller 50 can be implemented by using a single computer hardware, or by using a plurality of computer hardware to disperse various processes.

[0023] The controller 50 converts the total required driving force F fr , the detection values ​​of the vertical acceleration sensors 30fL and 30fR on the front wheel side, the detection values ​​of the vertical acceleration sensors 30rL and 30rR on the rear wheel side, and the suspension stroke S detected by the sensor not shown su As input information, the front wheel drive force F f , rear wheel driving force F r , front wheel braking force B f , and rear wheel braking force B r More specifically, the controller 50 controls the front wheel drive force F f , rear wheel driving force F r 、Front wheel braking force B f , and rear wheel braking force B r Instructions are issued to the front wheel inverter 12f, the rear wheel inverter 12r, the front wheel friction brake 14f, and the rear wheel friction brake 14r in a manner.

[0024] In particular, in the present embodiment, the controller 50 performs any of basic drive control, cooperative processing, and non-cooperative processing as control for regulating the distribution of driving force when the vehicle 100 is traveling forward (particularly, when accelerating).

[0025] The controller 50 performs basic driving control during normal driving (except for driving on rough roads described later in this embodiment). In the basic driving control, the controller 50 controls the front wheel driving force F f and rear wheel drive force F r The predetermined basic front wheel driving force and the basic rear wheel driving force are set respectively.

[0026] Here, the basic front-wheel driving force and the basic rear-wheel driving force are values ​​determined through experiments or simulations in order to obtain the desired characteristics of the vehicle characteristics (especially the power consumption performance) of the vehicle 100 corresponding to the driving scene. The specific values ​​of the basic front-wheel driving force and the basic rear-wheel driving force can be appropriately changed according to the specifications of the vehicle 100 and the driving scene. As an example, when driving straight on a flat paved road at a constant speed, it can be determined that the basic front-wheel driving force and the basic rear-wheel driving force are equal to the total required driving force F fr The basic front-wheel drive force and basic rear-wheel drive force distribution ratio is 50:50.

[0027] On the other hand, when the controller 50 detects a scene in which the vehicle 100 is traveling on a predetermined rough road based on various input information, it performs either a coordinated process or a non-coordinated process according to the magnitude (amplitude) of the rough road. It should be noted that in the present embodiment, the rough road refers to a road that has roughness within a constant distance in the traveling direction of the vehicle 100. In the following, in particular, a portion of the rough road that protrudes from a flat surface is referred to as a "mountain", and a portion that is lower than a flat surface is referred to as a "valley".

[0028] In the coordination process, the controller 50 executes either the first control mode or the second control mode according to the need to raise or lower the vehicle body.

[0029] In the first control mode, the controller 50 sets the front wheel braking force B f Set to a positive value to increase the front wheel drive force F f Set to a negative value and set the rear wheel drive force F r That is, the controller 50 causes the front wheel motor 10f to regenerate (responsibly brake the front wheel 11f), causes the rear wheel motor 10r to power run (responsibly drive the rear wheel 11r), and applies friction braking force to the front wheel 11f. In addition, in the second control mode, the controller 50 sets the front wheel driving force F f Set to a positive value to increase the rear wheel drive force F r Set it to a negative value and increase the rear wheel braking force B r That is, the controller 50 causes the front wheel motor 10f to power run (the front wheel 11f is powered and driven), causes the rear wheel motor 10r to regenerate (the rear wheel 11r is regeneratively braked), and on this basis, applies friction braking force to the rear wheel 11r.

[0030] On the other hand, in the non-cooperative process, the controller 50 executes any one of the third control mode and the fourth control mode according to the need to raise or lower the vehicle body.

[0031] In the third control mode, the controller 50 does not apply the front wheel braking force B f , but the front wheel drive force F f Set to a negative value and set the rear wheel drive force F r In addition, in the fourth control mode, the controller 50 does not apply the rear wheel braking force B r , but the front wheel drive force F f is set to a positive value, and the rear wheel drive force F r Set to a negative value.

[0032] Front wheel drive force F in coordinated and uncoordinated processing f , rear wheel driving force Fr , front wheel braking force B f , and rear wheel braking force B r The relationship between the adjustment and the suppression of the vertical displacement of the vehicle body will be described in more detail.

[0033] Figure 2 1 is a diagram showing the general structure of the chassis system of the vehicle 100 (particularly the general structure of the suspension geometry). f " represents the virtual rotation center (instantaneous rotation center) of the front part of the vehicle body in the pitch direction," r ” represents the virtual rotation center (instantaneous rotation center) of the rear part of the vehicle body in the pitch direction.

[0034] When the vehicle 100 is moving forward, a regenerative braking force (force in the opposite direction to the moving direction) is applied to the front wheel 11f and a powered driving force (force in the same direction as the moving direction) is applied to the rear wheel 11r. an On the other hand, when the power running driving force is applied to the front wheel 11f and the regenerative braking force is applied to the rear wheel 11r, a recoil force F acts on the vehicle body. sq (The force that causes the car body to sink).

[0035] Therefore, in theory, in a scenario where the vehicle 100 is traveling on an uneven road, the pitch adjustment (i.e., the above-mentioned non-coordinated processing) can be performed by adjusting the driving force distribution of the front wheels 11f and the rear wheels 11r, and the up and down displacement of the vehicle body (roll vibration) can be appropriately suppressed by raising or lowering the vehicle body.

[0036] On the other hand, the anti-recoil force F obtained by non-coordination processing an or recoil F sq The magnitude of the anti-squat angle θ (the anti-squat angle θ on the front side) of the suspension 40 (the front suspension 40f and the rear suspension 40r) of the vehicle 100 f and the anti-squat angle θ at the rear r ) size.

[0037] More specifically, the front wheel driving force F generated by the front wheel motor 10f is f and the rear wheel driving force F generated by the rear wheel motor 10r r The power is transmitted to the front wheel 11f and the rear wheel 11r using the front wheel drive shaft 21 and the rear wheel drive shaft 21r as points of action, respectively.

[0038] Therefore, the vertical component of the pitch force (i.e., the anti-recoil force F an or recoil F sqThe size of the anti-recoil angle θ is specified f ,θ r The virtual rotation center O is determined by the horizontal line and the structure of the suspension 40f, 40r. f , O r And the angle formed by the straight lines connecting the above points of action.

[0039] Therefore, the anti-squat angle θ cannot be increased in the structure of the suspension 40f, 40r. f ,θ r The case (virtual rotation center O f , O r In the case of a relatively low position), the anti-recoil force F obtained by adjusting the driving force distribution an or recoil F sq The scope is limited.

[0040] Especially Figure 2 The vehicle 100 of the present embodiment shown in the figure adopts a front anti-squat angle θ in consideration of riding comfort and front end nose-down during braking. f In the case of a relatively small suspension structure, there is a problem that a sufficient effect of suppressing the vertical displacement of the vehicle body cannot be obtained even if the non-coordinated processing is performed.

[0041] In contrast, the inventors of the present invention have found that by utilizing the front wheel braking force B f or rear wheel braking force B r By adjusting the net driving force distribution provided to the front wheel 11f and the rear wheel 11r beyond the adjustment range of the above-mentioned non-coordinated processing, even the vehicle 100 equipped with a suspension structure with a relatively small anti-recoil angle θ can obtain a high vehicle body vertical displacement suppression effect.

[0042] Figure 3 It is a diagram for explaining the effect of executing the coordination process. It should be noted that, in the following, in particular, the first control mode (applying the front wheel braking force B f , regenerative braking of the front wheel 11f, and power running driving of the rear wheel 11r) is the focus to explain the effect of the coordination process. On the other hand, the following description is also in the second control mode (power running driving the front wheel 11f, applying rear wheel braking force B r , and the same is also applicable to the regenerative braking of the rear wheel 11r).

[0043] As shown in the figure, when the first control mode is executed while the vehicle 100 is traveling forward, the front wheel braking force B f The point of action is the outer periphery of the front wheel 11f. Therefore, the virtual rotation center O of the front wheel side is set as a horizontal line. f and front wheel braking force B fThe anti-squat angle θ is determined by the angle formed by the straight lines connecting the points of action. Bf Compared with the above non-coordinated anti-recoil angle θ f Therefore, compared with the case where the third control mode is executed in the non-cooperative process, the case where the first control mode is executed in the cooperative process can further improve the effect of suppressing the vertical displacement of the vehicle body.

[0044] On the other hand, the cooperative process is a control for operating the mechanical brake actuator 14. Therefore, in terms of control responsiveness, the non-cooperative process, which is an electrical control not involving the operation of the mechanical actuator, is superior.

[0045] Therefore, below, in a scenario where the vehicle 100 is traveling on an uneven road, an example of appropriately performing either coordinated processing or non-coordinated processing will be described, separating the situation where the up and down displacement of the vehicle body should be prioritized to be suppressed and the situation where control responsiveness should be prioritized according to the size of the undulation of the traveling road surface.

[0046] Figure 4 This is a flowchart for explaining the driving force control method of this embodiment. Figure 4 The various processes shown are executed based on the time when the controller 50 determines that the vehicle 100 is traveling on an uneven road based on information about the road provided by a predetermined internal sensor mounted on the vehicle 100 or an external server. In particular, the controller 50 repeatedly executes the processing at every predetermined calculation cycle in this scenario. Figure 4 Various treatments shown.

[0047] In step S110 and step S120, the controller 50 determines the pitch rate ω pi and the vertical acceleration a G Whether each has exceeded the pitch rate threshold ω piTH And the upper and lower acceleration thresholds a GTH .

[0048] Here, the pitch rate ω pi is defined as the pitch angle θ pi The time differential (i.e., pitch angular velocity) of pi Determined as the displacement angle of the pitch direction relative to the horizontal direction around the center of gravity G of the vehicle 100 (refer to Figure 2 ). It should be noted that the pitch angle θ pi The sign of is set such that the direction in which the front wheel 11f of the vehicle 100 rises (the vehicle head is facing upward) is positive, and the direction in which the rear wheel 11r rises (the vehicle head is facing downward) is negative. G is the acceleration of the vertical displacement of the vehicle 100 (the center of gravity G of the vehicle 100).pi , pitch angle θ pi , and the vertical acceleration a G The calculation can be performed by a known method based on the detection values ​​of the vertical acceleration sensors 30fL and 30fR on the front wheel side, the detection values ​​of the vertical acceleration sensors 30rL and 30rR on the rear wheel side, and other necessary parameters.

[0049] Pitch rateω pi and vertical acceleration a G Both are parameters indicating the magnitude of the actual vertical displacement of the vehicle 100 when traveling on a rough road. In other words, they are parameters indicating the magnitude of the roughness of the rough road (roughness parameters).

[0050] In addition, the pitch rate threshold ω piTH And the upper and lower acceleration thresholds a GTH The value is determined to appropriately prioritize the effect of suppressing the vertical displacement of the vehicle 100 or the high control responsiveness. piTH And the upper and lower acceleration thresholds a GTH It is determined that when the undulation of the rough road is relatively large (when high control responsiveness is not required but high vertical displacement suppression effect is required), the coordination process is performed. piTH And the upper and lower acceleration thresholds a GTH It is determined that the non-cooperative process is executed when the undulations of the rough road are relatively small (when high control responsiveness is required but the required vertical displacement suppression effect is small).

[0051] Then, the controller 50 executes the process of step S130 when the determination results of step S110 and step S120 are both affirmative, and executes the non-coordination process (step S160 ) when the determination results of step S110 and step S120 are not affirmative.

[0052] In step S130, the controller 50 determines the suspension stroke amount S su Whether it exceeds the first travel threshold S suTH1 .

[0053] It should be noted that the suspension travel S su and pitch rate ω pi and vertical acceleration a G Similarly, it is also a fluctuation parameter indicating the magnitude of the actual up-and-down displacement of the vehicle 100 when traveling on a rough road. suTH1 From the perspective of judging whether the ups and downs of the road are so great that it is desirable to use the front wheel braking force B f or rear wheel braking force B rThe degree of vertical displacement of the vehicle 100 is suppressed by the coordinated processing and is determined to be an appropriate value.

[0054] Then, the controller 50 executes the coordination process (step S140 ) when the determination result of step S130 is affirmative, and executes the non-coordination process (step S160 ) when the determination result of step S130 is not affirmative.

[0055] It should be noted that, as a specific example of the coordination process, in a scenario where the vehicle 100 is traveling in a valley portion of an undulating road and a force in the vehicle body is generated in a downward direction, the controller 50 executes the first control mode (causing the vehicle body to rise) to eliminate the force. On the other hand, in a scenario where the vehicle 100 is traveling in a mountain portion of an undulating road and a force in the vehicle body is generated in an upward direction, the controller 50 executes the second control mode (causing the vehicle body to fall) to eliminate the force.

[0056] In addition, as an example of non-coordinated processing, in a scenario where the vehicle 100 is traveling in a valley portion of an undulating road and a force in the vehicle body is generated in a downward direction, the controller 50 executes the third control mode (causing the vehicle body to rise) to cancel the force. On the other hand, in a scenario where the vehicle 100 is traveling in a mountain portion of an undulating road and a force in the vehicle body is generated in an upward direction, the controller 50 executes the fourth control mode (causing the vehicle body to fall) to cancel the force.

[0057] It should be noted that the selection of the first control mode or the second control mode in the above-mentioned coordinated processing and the selection of the third control mode or the fourth control mode in the non-coordinated processing are examples and are not limited thereto. f , rear wheel driving force F r , front wheel braking force B f , and rear wheel braking force B r The specific value of is not limited to the specified value and can be adjusted appropriately according to the situation.

[0058] In addition, the controller 50 determines the suspension stroke amount S during the execution of the coordination process. su Is it lower than the second stroke threshold S? suTH2 (Step S150).

[0059] The second stroke amount threshold S suTH2 The appropriate value is set from the viewpoint of determining whether the undulation of the rough road has been reduced to a level that allows for determining whether the cooperative process should be switched to the non-cooperative process in consideration of the control responsiveness.

[0060] Furthermore, when the controller 50 determines the suspension travel amount S su Below the second stroke threshold SsuTH2 When the control is switched from coordinated processing to non-coordinated processing (step S160), the program ends.

[0061] It should be noted that, considering the low control responsiveness of the above-mentioned coordination process, it is also possible to adopt the suspension stroke amount S su The second stroke amount threshold S is lowered for many times suTH2 In the case of , the structure of switching from the coordinated processing to the non-coordinated processing is executed. In particular, it takes a constant time from the start of the coordinated processing according to the determination result of step S130 to the actual suppression effect of the vertical displacement of the vehicle body. Taking this into consideration, the above structure can prevent the front wheel braking force B from being suppressed after the start of the coordinated processing. f or rear wheel braking force B r Whether the command has not been followed yet, temporarily detect the suspension stroke S su In addition, in the determination of the above step S150 (determination of whether to switch from the coordinated process to the non-coordinated process), the reference pitch rate ω may be appropriately used. pi and / or vertical acceleration a G The results are compared with the magnitudes of the respective determined thresholds.

[0062] Figure 5 1 is a timing chart showing an example of the time-series change of each control parameter when the control of the present embodiment is executed in a scene of driving on an uneven road. Figure 5 In the timing diagram, the pitch angle θ pi and pitch rate ω pi The direction in which the front of the vehicle 100 is facing upward is positive, and the vertical acceleration a G In the upward direction relative to the vehicle 100, the suspension travel amount S su The direction of compression of the suspension 40 is positive.

[0063] As shown in the figure, at the pitch rate ω pi , vertical acceleration a G , and suspension travel S su In a section where all the values ​​are equal to or less than the respective threshold values ​​(time t<t1), that is, in a scene where the roughness of the rough road is estimated to be relatively small, priority is given to controlling the responsiveness and the non-cooperative process is executed.

[0064] Then, when the pitch rate ω pi , vertical acceleration a G , and suspension travel S su (exist Figure 5 In particular, the suspension travel S on the rear wheel side su) all exceed their respective thresholds (time t=t1), that is, when it is estimated that the vehicle enters an interval with relatively large undulations on an undulating road, the control is switched from non-coordinated processing to coordinated processing from the perspective of enhancing the effect of suppressing the up and down displacement of the vehicle body.

[0065] Afterwards, when the suspension travel S su (exist Figure 5 The suspension travel S of both the front wheel side and the rear wheel side su ) is lower than the second stroke threshold S suTH2 When, that is, when it is estimated that the vehicle has entered a section where the undulations of the rough road are relatively small, the control is switched again from the cooperative processing to the non-cooperative processing.

[0066] Figure 6 It is executed in Figure 5 As shown in the figure, in the control of this embodiment, the pitch rate ω, which is a parameter indicating the magnitude of the vertical displacement, is pi , vertical acceleration a G And suspension travel S su (see the dotted line) are reduced compared to the parameters of the comparative example (see the solid line) which maintains the basic drive control even during the rough road travel.

[0067] Next, the structure and effects of the above-mentioned embodiment will be summarized and described.

[0068] In this embodiment, a driving force control method is provided, which uses a front wheel motor 10f connected to a front wheel 11f of a vehicle 100 and a rear wheel motor 10r connected to a rear wheel 11r to control the front wheel driving force F f and rear wheel drive force F r .

[0069] In the driving force control method, a coordination process is performed (step S140) to coordinate the front wheel driving force F f and rear wheel drive force F r The adjustment of at least one of the friction braking force and the friction braking force relative to at least one of the front wheel 11f and the rear wheel 11r (front wheel braking force B f or rear wheel braking force B r ) is applied to coordinate the rise or fall of the vehicle body.

[0070] Therefore, the front wheel drive force F f and rear wheel drive force F r Compared with the case where the vehicle body is raised or lowered by the control, the effect of suppressing the up and down displacement (roll vibration) of the vehicle 100 can be further improved.

[0071] In particular, the coordination process (step S140) includes a first control mode for raising the vehicle body and a second control mode for lowering the vehicle body. In the first control mode, a friction braking force (front wheel braking force B f ), and the rear wheel motor 10r is powered. In the second control mode, the front wheel motor 10f is powered, and a friction braking force (rear wheel braking force B) is applied to the rear wheel 11r. r ).

[0072] This realizes a more specific control method for raising or lowering the vehicle body in the cooperative process when the vehicle 100 is traveling forward.

[0073] In addition, the driving force control method of the present embodiment is further executed by adjusting only the front wheel driving force F f and rear wheel drive force F r The non-cooperative process includes a third control mode in which the front wheel motor 10f is regenerated and the rear wheel motor 10r is powered, and a fourth control mode in which the front wheel motor 10f is powered and the rear wheel 11r is powered.

[0074] Thus, the vehicle body can be raised or lowered by appropriately replacing the coordinated processing according to the driving scene of the vehicle 100 and the like, and performing the raising or lowering of the vehicle body by the non-coordinated processing with high control responsiveness. f and rear wheel drive force F r " indicates that the control operation amount for raising or lowering the vehicle body includes the front wheel drive force F f and rear wheel drive force F r Therefore, the above statement is not intended to exclude from the technical scope of the present invention the manner in which the control logic using the operation amount other than the friction braking force for assisting the action of raising or lowering the vehicle body in the non-coordinated processing is included.

[0075] In addition, in the driving force control method of the present embodiment, when the vehicle 100 is traveling on a rough road, a roughness parameter (pitch rate ω) indicating the magnitude of the roughness of the rough road is obtained. pi , vertical acceleration a G , and suspension travel S su ). Also, during the execution of the non-coordinated processing, when the undulation parameter exceeds a predetermined first threshold value (pitch rate threshold value ω piTH , upper and lower acceleration threshold a GTH , and / or the first stroke threshold S suTH1), the non-coordinated processing is switched to the coordinated processing (steps S110 to S130, and step S140).

[0076] Thus, it is possible to appropriately select the cooperative process having the effect of suppressing the vertical displacement and the non-cooperative process having high control responsiveness according to the magnitude of the ups and downs of the vehicle 100 on the rough road.

[0077] In particular, in the present embodiment, when the fluctuation parameter (particularly the suspension travel S su ) is lower than the specified second threshold (the second stroke threshold S suTH2 ), the coordinated processing is switched to the uncoordinated processing.

[0078] Thus, it is possible to more appropriately select the cooperative process having the effect of suppressing the vertical displacement and the non-cooperative process having high control responsiveness according to the degree of the fluctuation of the vehicle 100 on the uneven road.

[0079] In addition, in the present embodiment, a controller 50 is provided that functions as a driving force control device for executing the above-mentioned driving force control method. The controller 50 controls the front wheel driving force F F F respectively by using the front wheel motor 10f connected to the front wheel 11f of the vehicle 100 and the rear wheel motor 10r connected to the rear wheel 11r. f and rear wheel drive force F r .

[0080] In particular, the controller 50 includes a coordination processing unit (step S140) which coordinates the front wheel driving force F f and rear wheel drive force F r The adjustment of at least one of the friction braking force with respect to at least one of the front wheel 11f and the rear wheel 11r (front wheel braking force B f or rear wheel braking force B r ) is applied to coordinate the rise or fall of the vehicle body.

[0081] Thus, a structure of a control device suitable for executing the above-mentioned driving force control method is realized.

[0082] Although the embodiments of the present invention have been described above, the above embodiments merely represent a part of application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments.

[0083] For example, in the above embodiment, an example of performing either non-coordinated processing or coordinated processing according to the size of the bumps in a scene where the vehicle 100 is traveling on an uneven road is described. However, the present invention is not limited thereto, and the same control can be performed in other driving scenes where it is assumed that the vehicle 100 is suppressed from moving up and down.

[0084] In addition, the specific method for the above-mentioned undulation parameter is not limited to that described in the above-mentioned embodiment. For example, any vehicle-mounted sensor such as Lidar, camera, and / or radar can also be used to obtain information related to the undulation of the undulating road, and the value of the undulation size directly estimated based on the information is used as the undulation parameter. In addition, the parameters used in the judgment of switching from non-coordinated processing to coordinated processing are not limited to the above-mentioned undulation parameters. For example, the following structure can also be adopted, that is, based on the information obtained from the server on the vehicle or outside the vehicle, a parameter representing the period length of the undulating valley of the undulating road is obtained, and based on the parameter, it is judged whether to switch from non-coordinated processing to coordinated processing.

[0085] In addition, in the above-mentioned embodiment, an example of coordinating the adjustment of the driving force distribution (pitch adjustment) with respect to each driving wheel and the application of the friction braking force in both the first control mode (ascending control) and the second control mode (descending control) of the coordinated process is described. However, this is not limited to this, and a control method in which the friction braking force is applied only to one of the first control mode and the second control mode in the coordinated process may also be adopted. For example, a control method in which the front wheel braking force B is applied in the first control mode (ascending control) of the coordinated process f , and in the second control mode (descent control), no rear wheel braking force B is applied. r It should be noted that if Figure 2 As shown, the control logic is particularly preferably applied to a vehicle body structure in which the anti-squat angle θ of the front side of the vehicle body structure is f is relatively small, and the anti-recoil angle θ on the rear side r It is relatively large, so for the rear side, sufficient raising / lowering amount can be ensured simply by adjusting the driving force distribution.

[0086] In addition, in the above-mentioned embodiment, as a non-coordinated process, an example of a control method for adjusting the pitch displacement by adjusting only the driving force distribution of the vehicle 100 is described. However, instead of this, a control method can be adopted in which the non-coordinated process is used as an arbitrary driving force distribution for purposes other than the purpose of adjusting the pitch displacement (for example, a basic driving control for determining the driving force distribution during normal driving). For example, by making the non-coordinated process the basic driving control, a control method that appropriately realizes direct switching between the basic driving control and the coordinated process (without switching through the pitch adjustment by adjusting the driving force distribution) according to the conditions of the driving road surface such as the size of the undulations of the uneven road is also included in the technical scope of the present invention.

Claims

1. A driving force control method, using a front wheel motor connected to a front wheel of a vehicle and a rear wheel motor connected to a rear wheel to control the front wheel driving force and the rear wheel driving force respectively, wherein the driving force control method is characterized in that: The pitch rate, vertical acceleration, and suspension stroke of the vehicle are obtained as fluctuation parameters representing the vertical displacement of the vehicle corresponding to the fluctuation of the road surface on which the vehicle is traveling. By referring to the fluctuation parameter, the requirement for suppressing the up and down displacement is judged. According to the judgment result of the level of the requirement, the coordinated processing and the non-coordinated processing are switched and executed. In the coordination process, the adjustment of at least one of the front wheel driving force and the rear wheel driving force is coordinated with the application of the friction braking force to at least one of the front wheel and the rear wheel to raise or lower the vehicle body. In the non-coordinated processing, the vehicle body is raised or lowered by adjusting only the front wheel driving force and the rear wheel driving force.

2. The driving force control method according to claim 1, characterized in that: The coordination process includes: a first control mode for raising the vehicle body, and a second control mode for lowering the vehicle body. In the first control mode, a friction braking force is applied to the front wheel to cause the rear wheel motor to operate with power. In the second control mode, the front wheel motor is powered, and a friction braking force is applied to the rear wheel, or the rear wheel motor is regenerated.

3. The driving force control method according to claim 1 or 2, characterized in that: The non-coordinated processing includes a third control mode in which the front wheel motor is regenerated and the rear wheel motor is powered, and a fourth control mode in which the front wheel motor is powered and the rear wheel motor is regenerated.

4. The driving force control method according to claim 3, characterized in that: When the vehicle is traveling on an uneven road, Obtain the fluctuation parameter, In the execution of the non-coordinated processing, When the fluctuation parameter exceeds a prescribed first threshold, the non-coordinated processing is switched to the coordinated processing.

5. The driving force control method according to claim 4, characterized in that: In the execution of the coordination process, When the fluctuation parameter is lower than a specified second threshold, the coordinated process is switched to the non-coordinated process.

6. A driving force control device, which uses a front wheel motor connected to the front wheels of a vehicle and a rear wheel motor connected to the rear wheels to control the front wheel driving force and the rear wheel driving force respectively, wherein the driving force control device is characterized in that: The pitch rate, vertical acceleration, and suspension stroke of the vehicle are obtained as fluctuation parameters representing the vertical displacement of the vehicle corresponding to the fluctuation of the road surface on which the vehicle is traveling. By referring to the fluctuation parameter, the requirement for suppressing the up and down displacement is judged. According to the result of the judgment of the level of the requirement, the coordinated processing and the non-coordinated processing are switched and executed, wherein the coordinated processing coordinates the adjustment of at least one of the front wheel driving force and the rear wheel driving force and the application of the friction braking force to at least one of the front wheel and the rear wheel to raise or lower the vehicle body, In the non-coordinated processing, the vehicle body is raised or lowered by adjusting only the front wheel driving force and the rear wheel driving force.

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