Vehicle Control System

Abstract

To provide a vehicle control system which is appropriately free from slip while suppressing decline in acceleration or deceleration and destabilization of vehicle behavior.SOLUTION: A vehicle control system 10 comprises: a traction control part 11; a front motor control part 15; and a rear motor control part 17. The traction control part 11 controls traction of each of a plurality of wheels W. Each of the motor control parts 15, 17 controls each of a plurality of rotary electric machines M exchanging torque between the plurality of wheels W based on axle speed information inputted from the traction control part 11. The traction control part configures an axle speed threshold value Vth between a target axle speed Vw and a vehicle body speed Vv to determine a need for execution of prescribed torque control performed by each of the motor control parts 15, 17 so as to resolve slip of each of the wheels W and outputs axel speed information regarding the axle speed threshold value Vth to each of the motor control parts 15, 17.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle control system. [Background technology]

[0002] In recent years, efforts to provide access to sustainable transport systems that take into consideration vulnerable transport participants such as the elderly, people with disabilities, and children have been gaining momentum. To achieve this, we are focusing on research and development to further improve transport safety and convenience through development of vehicle behavior stability. Conventionally, a traction control device has been known that, when a drive wheel slips, reduces the torque of the motor, which is the power source, to eliminate the slip, by using a slip ratio only in the region where the cornering power of the drive wheel is high, thereby suppressing fluctuations in the wheel speed of the drive wheel and fluctuations in acceleration in the longitudinal direction of the vehicle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-115644 Summary of the Invention [Problem to be solved by the invention]

[0004] In terms of vehicle behavior stability, when wheel slip occurs during acceleration or deceleration, it is important to eliminate the slip while suppressing a decrease in acceleration or deceleration and destabilization of vehicle behavior. For example, the above-mentioned conventional traction control devices do not disclose a slip ratio threshold used to deactivate traction control, and may not be able to quickly stop traction control when slippage is eliminated. For example, if slippage is suddenly eliminated due to a change in road surface friction, such as a change from snow to asphalt during vehicle acceleration, the delay in stopping responsiveness of the traction control may prevent appropriate acceleration from being achieved.

[0005] The present invention aims to solve the above-mentioned problems by appropriately eliminating slippage while suppressing a decrease in acceleration or deceleration and destabilizing vehicle behavior, thereby contributing to the development of sustainable transportation systems. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1): A vehicle control system according to one aspect of the present invention (e.g., vehicle control system 10 in the embodiments) includes a traction control unit (e.g., traction control unit 11 in the embodiments) that controls the traction of drive wheels (e.g., wheel W, front wheel WF, rear wheel WR in the embodiments), and a rotating electric machine control unit (e.g., front motor control unit 15, rear motor control unit 17 in the embodiments) that controls the operation of a rotating electric machine (e.g., rotating electric machine M, front motor MF, rear motor MR in the embodiments) that exchanges torque with the drive wheels based on information (e.g., axle speed information in the embodiments) input from the traction control unit. The traction control unit sets an axle speed threshold (e.g., axle speed threshold Vth in the embodiments) for determining the end of execution of a predetermined torque control performed by the rotating electric machine control unit to eliminate slippage of the drive wheels, between a target axle speed (e.g., target axle speed Vw in the embodiments) and a vehicle speed (e.g., vehicle speed Vv in the embodiments), and outputs the information regarding the axle speed threshold to the rotating electric machine control unit.

[0007] (2): In the vehicle control system described in (1) above, the traction control unit may set the axle speed threshold during acceleration to the larger of a value (e.g., subtraction value Vsub in the embodiment) obtained by subtracting a first predetermined value (e.g., predetermined initial value ΔV0 in the embodiment) from the target axle speed, or a predetermined lower threshold (e.g., minimum axle speed threshold VthL in the embodiment), and may set the axle speed threshold during deceleration to the smaller of a value (e.g., addition value Vadd in the embodiment) obtained by adding a second predetermined value (e.g., predetermined initial value ΔV0 in the embodiment) to the target axle speed, or a predetermined upper threshold (e.g., maximum axle speed threshold VthH in the embodiment).

[0008] (3): In the vehicle control system described in (2) above, the rotating electric machine control unit may set the axle speed threshold value during acceleration to be equal to the target axle speed when the target axle speed during acceleration is smaller than the predetermined lower threshold value, and may set the axle speed threshold value during deceleration to be equal to the target axle speed when the target axle speed during deceleration is greater than the predetermined upper threshold value.

[0009] (4) In the vehicle control system described in (2) or (3) above, the traction control unit may set the predetermined lower threshold value and the predetermined upper threshold value based on a vehicle body state. [Effects of the Invention]

[0010] According to the above (1), by providing a traction control unit that sets the axle speed threshold between the target axle speed and the vehicle body speed, the rotating electric machine control unit can quickly terminate the predetermined torque control when the drive wheel slip has been resolved or has settled to an acceptable level, without needing the vehicle body speed to determine whether the drive wheels are slipping. For example, by preventing the execution of the predetermined torque control that reduces the torque of the drive wheels from being continued for an excessive period, the drive wheel slip can be appropriately resolved while preventing a decrease in acceleration or deceleration and destabilization of the vehicle behavior.

[0011] In the case of (2) above, an axle speed threshold can be set to determine whether to terminate the execution of the specified torque control just before the slippage of the drive wheels is eliminated or reduced to an acceptable level during acceleration and deceleration, thereby enabling the execution of the specified torque control to be terminated quickly and appropriately.

[0012] In the case of (3) above, an axle speed threshold can be set to determine whether or not to execute the specified torque control when the slippage of the drive wheels has been eliminated or is within an acceptable level during both acceleration and deceleration, and the execution of the specified torque control can be appropriately started and ended when slippage of the drive wheels occurs.

[0013] In the case of (4) above, it is possible to properly determine whether the slippage of the drive wheels has been eliminated or has been reduced to an acceptable level depending on the vehicle state, and the responsiveness of the end of execution of the specified torque control can be properly and accurately improved. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a functional configuration of a vehicle control system according to an embodiment of the present invention. [Figure 2] 3 is a flowchart showing the operation of the vehicle control system according to the embodiment of the present invention. [Figure 3] 10 is a graph showing an example of the correspondence between an axle speed, a target axle speed, an axle speed threshold, a vehicle speed, an operation flag, and an offset amount during vehicle acceleration in the vehicle control system according to the embodiment of the present invention. FIG. [Figure 4] 6 is a graph showing an example of the correspondence relationship between the target axle speed, the axle speed threshold, the minimum axle speed threshold, and the vehicle speed and the offset amount during vehicle acceleration in the vehicle control system according to the embodiment of the present invention. FIG. [Figure 5] 6 is a graph showing an example of the correspondence relationship between the offset amount and the target axle speed, the axle speed threshold, the maximum axle speed threshold, and the vehicle speed during vehicle deceleration in the vehicle control system according to the embodiment of the present invention. FIG. [Figure 6] FIG. 3 is a graph showing an example of the correspondence relationship between a predetermined value and a vehicle speed in the vehicle control system according to the embodiment of the present invention. [Figure 7]FIG. 10 is a graph showing another example of the correspondence relationship between the predetermined value and the vehicle speed in the vehicle control system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control system according to an embodiment of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing the functional configuration of a vehicle control system 10 according to an embodiment. The vehicle control system 10 of the embodiment is mounted on an electric vehicle (vehicle) such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. An electric vehicle is driven by a battery as a power source. A hybrid vehicle is driven by a battery and an internal combustion engine as a power source. A fuel cell vehicle is driven by a fuel cell as a power source.

[0016] The vehicle control system 10 in the embodiment controls, for example, an electric vehicle equipped with a plurality of rotating electric machines M that exchange torque with a plurality of wheels W, and an alarm device that presents various information to the driver. The rotating electric machine M is, for example, a three-phase AC brushless DC motor. The rotating electric machine M generates drive torque on the wheels W by performing power running operation using power supplied from a power conversion device or the like. The rotating electric machine M generates power and generates braking torque on the wheels W by performing regenerative operation using rotational power input from the wheels W. The rotating electric machine M is, for example, a front motor MF connected to the left and right front wheels WF, and a rear motor MR connected to the left and right rear wheels WR.

[0017] As shown in FIG. 1, the vehicle control system 10 includes, for example, a traction control unit 11, a wheel torque control unit 13, a front motor control unit 15, a rear motor control unit 17, and a meter 19. Each of the control units 11, 13, 15, and 17 is a software function unit that functions when a processor such as a CPU (Central Processing Unit) executes a predetermined program. The software function unit is an ECU that includes a processor such as a CPU, a ROM (Read Only Memory) that stores programs, a RAM (Random Access Memory) that temporarily stores data, and electronic circuits such as a timer. At least a part of each of the control units 11, 13, 15, and 17 may be an integrated circuit such as an LSI (Large Scale Integration).

[0018] Each of the control units 11, 13, 15, and 17 acquires detection value signals output from various sensors. The various sensors include, for example, an operation amount sensor that detects whether or not an accelerator operator and a brake operator are operated by the driver and the amount of operation, a current sensor that detects the current of the rotating electric machine M, a voltage sensor that detects the voltage, a rotation angle sensor that detects the rotation angle of the rotating electric machine M, an acceleration sensor that detects the acceleration of the vehicle, and a wheel speed sensor that detects the rotation speed (wheel speed) of each wheel W of the vehicle.

[0019] The traction control unit 11 constitutes part of a device that stabilizes the vehicle posture by suppressing sudden changes in vehicle behavior, such as a so-called TCS (Traction Control System). The traction control unit 11 suppresses slippage of the drive wheels (so-called slip) on slippery road surfaces, for example, to ensure the desired driving force, braking force, and steering ability. For example, the traction control unit 11 controls the traction of each of the multiple wheels W by setting a target axle speed Vw and an axle speed threshold Vth for each of the multiple rotating electric machines M. The traction control unit 11 sets a target axle speed Vw and an axle speed threshold Vth for each of the front motor MF, which exchanges torque with the left and right front wheels WF of the vehicle, and the rear motor MR, which exchanges torque with the left and right rear wheels WR of the vehicle.

[0020] The traction control unit 11 sets, for example, a target axle speed Vw and an axle speed threshold Vth as thresholds for determining whether or not to execute predetermined torque control, which is executed by each of the front motor control unit 15 and the rear motor control unit 17 described below. The predetermined torque control is, for example, a process for controlling the torque of each rotating electric machine M to eliminate slippage of the wheels W, which are drive wheels. The traction control unit 11 sets, for example, the target axle speed Vw as an intervention threshold for determining the start of execution of the predetermined torque control, and sets the axle speed threshold Vth as an intervention threshold for determining the end of execution of the predetermined torque control.

[0021] The traction control unit 11 sets, for example, an axle speed threshold Vth between a target axle speed Vw and a vehicle body speed Vv. For example, the traction control unit 11 acquires detection value signals output from an acceleration sensor and a wheel speed sensor, and acquires the vehicle speed (vehicle body speed) Vv by performing a predetermined calculation based on the acceleration and wheel speeds or by map search. For example, the traction control unit 11 sets a predetermined offset amount ΔV as information related to the axle speed threshold Vth. For example, the axle speed threshold Vth during vehicle acceleration is set by subtracting the offset amount ΔV from the target axle speed Vw (Vth=Vw-ΔV), and the axle speed threshold Vth during vehicle deceleration is set by adding the offset amount ΔV to the target axle speed Vw (Vth=Vw+ΔV).

[0022] The traction control unit 11 transmits axle speed information including, for example, a target axle speed Vw and a predetermined offset amount ΔV, which is information related to an axle speed threshold Vth, to each of the front motor control unit 15 and the rear motor control unit 17, which will be described later. The traction control unit 11 receives, for example, information indicating the operating state of predetermined torque control transmitted from each of the front motor control unit 15 and the rear motor control unit 17, which will be described later. The traction control unit 11 acquires the state of the vehicle by performing a predetermined estimation process or the like based on various information received from the outside, such as information indicating the operating state of the predetermined torque control. For example, the traction control unit 11 instructs a meter 19 (described later) to execute a notification that the predetermined torque control is operating or stopped.

[0023] The wheel torque control unit 13 controls torque transmission to each wheel W of the vehicle, such as in a so-called AWD (All Wheel Drive) system. The wheel torque control unit 13 optimizes torque distribution to the front, rear, left, and right wheels W in various driving states, such as acceleration, deceleration, and cornering of the vehicle, to ensure desired driving stability. For example, the wheel torque control unit 13 controls the torque to be distributed to each of the multiple wheels W by setting a required torque for each of the multiple rotating electric machines M in accordance with the torque required by the driver of the vehicle through accelerator operation, brake operation, or the like. The wheel torque control unit 13 sets a required torque for each of the front motor MF and the rear motor MR. The wheel torque control unit 13 transmits information about the required torque through communication with each of the front motor control unit 15 and the rear motor control unit 17, which will be described later.

[0024] Each of the front motor control unit 15 and the rear motor control unit 17 includes a power conversion device connected to a power source such as a power storage device mounted on the vehicle. Each of the motor control units 15, 17 controls the exchange of power between the front motor MF and the rear motor MR via a power conversion device configured, for example, with a plurality of switching elements. Each of the motor control units 15, 17 generates rotational driving force by sequentially commutating current to the three-phase stator windings of the rotating electric machine M during power running of the rotating electric machine M (each of the motors MF, MR). Each of the motor control units 15, 17 converts three-phase AC power input from the three-phase stator windings into DC power by switching the phases synchronized with the rotation of the rotating electric machine M during regenerative operation of the rotating electric machine M (each of the motors MF, MR).

[0025] Each motor control unit 15, 17 performs feedback control of the rotation speed and torque of the rotating electric machine M (each motor MF, MR) based on the axle speed information input from the traction control unit 11, the required torque input from the torque control unit 13, and the detected values ​​input from various sensors.

[0026] Each motor control unit 15, 17 acquires, for example, a detected value of the rotational speed of each rotating electric machine M output from a rotation angle sensor, and acquires an axle speed Vs in terms of speed according to the rotational speed of each rotating electric machine M. Each motor control unit 15, 17 calculates an axle speed threshold Vth using, for example, the target axle speed Vw acquired from the traction control unit 11 and a predetermined offset amount ΔV. As described above, the axle speed threshold Vth during vehicle acceleration is calculated by subtracting the offset amount ΔV from the target axle speed Vw (Vth = Vw - ΔV), and the axle speed threshold Vth during vehicle deceleration is calculated by adding the offset amount ΔV to the target axle speed Vw (Vth = Vw + ΔV). Each motor control unit 15, 17 determines whether or not to start execution of a predetermined torque control for eliminating slippage of the wheels W, which are drive wheels, based on, for example, a comparison between the axle speed Vs and the target axle speed Vw. Each motor control unit 15, 17 determines whether or not to end execution of the predetermined torque control based on, for example, a comparison between the axle speed Vs and the axle speed threshold Vth.

[0027] The meter 19 is part of an informing device mounted on the vehicle. The meter 19 notifies various information in response to command signals and the like input from the respective control units 11, 13, 15, and 17. For example, the meter 19 notifies information indicating whether the predetermined torque control by the respective motor control units 15 and 17 is in operation or stopped by blinking a lamp or the like.

[0028] An example of the operation of the vehicle control system 10 according to the embodiment will be described below. 2 is a flowchart showing the operation of the traction control unit 11 among the operations of the vehicle control system 10 of the embodiment. The traction control unit 11 repeatedly executes a series of processes from step S01 to step S04 shown in FIG. 2 at a predetermined interval or the like. As shown in FIG. 2, first, the traction control unit 11 acquires, for example, the detected values ​​of acceleration and wheel speed output from an acceleration sensor and a wheel speed sensor, and acquires the vehicle speed Vv by performing a predetermined calculation or map search based on the acceleration and wheel speed (step S01).

[0029] Next, the traction control unit 11 sets a target axle speed Vw, and also sets an axle speed threshold Vth between the target axle speed Vw and the vehicle speed Vv (step S02). Next, the traction control unit 11 sets a predetermined offset amount ΔV according to the axle speed threshold Vth for each of acceleration and deceleration of the vehicle (step S03). Next, the traction control unit 11 transmits axle speed information including the target axle speed Vw and the predetermined offset amount ΔV to each of the motor control units 15, 17 (step S04).Then, the traction control unit 11 advances the processing to END.

[0030] Below, an example of the operation of the vehicle control system 10 in this embodiment when the vehicle accelerates and when the vehicle decelerates will be described. Note that in the following Figures 3, 4, and 5, an example will be described in which the front motor MF is controlled in response to the occurrence of slippage in the left and right front wheels WF. Fig. 3 is a graph showing an example of the correspondence relationship between the axle speed Vs, the target axle speed Vw, the axle speed threshold Vth, and the vehicle body speed Vv, and the operation flag, and the offset amount ΔV, during vehicle acceleration in the vehicle control system 10 of the embodiment. Fig. 4 is a graph showing an example of the correspondence relationship between the target axle speed Vw, the axle speed threshold Vth, the minimum axle speed threshold VthL, and the vehicle body speed Vv, and the offset amount ΔV, during vehicle acceleration in the vehicle control system 10 of the embodiment.

[0031] During vehicle acceleration as shown in Figures 3 and 4, the traction control unit 11 sets the axle speed threshold Vth to the larger of a value (subtraction value Vsub) obtained by subtracting a first predetermined value from the target axle speed Vw or a predetermined lower threshold. For example, the traction control unit 11 sets a predetermined initial value ΔV0 of the offset amount ΔV as the first predetermined value. For example, the traction control unit 11 sets a minimum axle speed threshold VthL (=Vv+α) obtained by adding a predetermined value α to the vehicle speed Vv as the predetermined lower threshold.

[0032] The predetermined lower threshold is, for example, a threshold for the axle speed Vw for determining whether slippage of each wheel W has been eliminated or has been reduced to an acceptable level during vehicle acceleration. The offset amount ΔV during vehicle acceleration is set, for example, so that the axle speed threshold Vth does not become less than the predetermined lower threshold. For example, by setting the minimum axle speed threshold VthL (=Vv+α) as the predetermined lower threshold, the axle speed threshold Vth is always greater than the vehicle speed Vv, even if the target axle speed Vw changes. The predetermined value α is, for example, a value corresponding to the amount of slippage when it is determined that slippage of each wheel W has been eliminated or has been reduced to an acceptable level.

[0033] First, as from time t0 onwards, for example, when the axle speed Vs increases to or exceeds the vehicle speed Vv, the traction control unit 11 changes the offset amount ΔV from zero to a predetermined initial value ΔV0. Next, for example, after time t1, as the axle speed Vs increases to or above the target axle speed Vw, the front motor control unit 15 sets the start of execution of a predetermined torque control to eliminate slippage of the front wheels WF by changing the flag value of the operation flag from zero to "1." For example, when the subtraction value Vsub (=Vw-ΔV0) is greater than the minimum axle speed threshold VthL (=Vv+α), such as during the period from time t0 to time t2, the traction control unit 11 sets the subtraction value Vsub (=Vw-ΔV0) as the axle speed threshold Vth.

[0034] Next, as from time t2 onwards, for example, as the subtraction value Vsub (=Vw-ΔV0) falls below the minimum axle speed threshold VthL (=Vv+α) and the minimum axle speed threshold VthL (=Vv+α) increases towards the target axle speed Vw, the traction control unit 11 decreases the offset amount ΔV from the predetermined initial value ΔV0 towards zero. The traction control unit 11 sets the minimum axle speed threshold VthL (=Vv+α) as the axle speed threshold Vth.

[0035] Next, as from time t3 onwards, for example, as the target axle speed Vw drops below the minimum axle speed threshold VthL (=Vv+α), the traction control unit 11 sets the offset amount ΔV to zero. The traction control unit 11 sets the target axle speed Vw as the axle speed threshold Vth. Next, for example, after time t4, when the axle speed Vs drops below the axle speed threshold Vth (= target axle speed Vw), the front motor control unit 15 changes the flag value of the operation flag from "1" to zero, thereby setting the end of the execution of the predetermined torque control to eliminate slippage of the front wheels WF.

[0036] FIG. 5 is a graph showing an example of the correspondence between the target axle speed Vw, the axle speed threshold Vth, the maximum axle speed threshold VthH, and the vehicle body speed Vv and the offset amount ΔV during vehicle deceleration in the vehicle control system 10 of the embodiment. During vehicle deceleration as shown in Fig. 5, the traction control unit 11 sets the axle speed threshold Vth to the smaller of, for example, a value (additional value Vadd) obtained by adding a second predetermined value to the target axle speed Vw, or a predetermined upper threshold. The traction control unit 11 sets, for example, a predetermined initial value ΔV0 of the offset amount ΔV as the second predetermined value. The traction control unit 11 sets, for example, a maximum axle speed threshold VthH (=Vv-α) obtained by subtracting a predetermined value α from the vehicle speed Vv as the predetermined upper threshold.

[0037] The predetermined upper threshold is, for example, a threshold for the axle speed Vw for determining whether slippage of each wheel W has been eliminated or has been reduced to an acceptable level during vehicle deceleration. The offset amount ΔV during vehicle deceleration is set, for example, so that the axle speed threshold Vth does not become larger than the predetermined upper threshold. For example, by setting the maximum axle speed threshold VthH (=Vv-α) as the predetermined upper threshold, the axle speed threshold Vth is always smaller than the vehicle speed Vv, even if the target axle speed Vw changes. The predetermined value α is, for example, a value corresponding to the amount of slippage when it is determined that slippage of each wheel W has been eliminated or has been reduced to an acceptable level.

[0038] First, as from time t0 onwards, for example, when the axle speed Vs (not shown) drops below the vehicle speed Vv, the traction control unit 11 changes the offset amount ΔV from zero to a predetermined initial value ΔV0. Next, as from time t11 onwards, for example, when the axle speed Vs (not shown) drops below the target axle speed Vw, the front motor control unit 15 sets the start of execution of a predetermined torque control to eliminate slippage of the front wheels WF by changing the flag value of the operation flag (not shown) from zero to "1". For example, when the additional value Vadd (=Vw+ΔV0) is smaller than the maximum axle speed threshold VthH (=Vv-α), such as during the period from time t0 to time t12, the traction control unit 11 sets the additional value Vadd (=Vw+ΔV0) as the axle speed threshold Vth.

[0039] Next, as from time t12 onwards, for example, as the additional value Vadd (=Vw+ΔV0) increases above the maximum axle speed threshold VthH (=Vv-α) and the maximum axle speed threshold VthH (=Vv-α) decreases towards the target axle speed Vw, the traction control unit 11 decreases the offset amount ΔV from the predetermined initial value ΔV0 towards zero. The traction control unit 11 sets the maximum axle speed threshold VthH (=Vv-α) as the axle speed threshold Vth.

[0040] Next, as from time t13 onwards, for example, as the target axle speed Vw increases to or exceeds the maximum axle speed threshold VthH (=Vv-α), the traction control unit 11 sets the offset amount ΔV to zero. The traction control unit 11 sets the target axle speed Vw as the axle speed threshold Vth. Then, for example, when the axle speed Vs (not shown) increases above the axle speed threshold Vth (= target axle speed Vw), the front motor control unit 15 changes the flag value of the operation flag (not shown) from "1" to zero, thereby setting the end of the execution of the predetermined torque control for eliminating slippage of the front wheels WF.

[0041] 3, 4, and 5, the traction control unit 11 sets the predetermined value α for setting each of the minimum axle speed threshold VthL (=Vv+α) and the maximum axle speed threshold VthH (=Vv-α) to a constant fixed value or a variable value that changes depending on the vehicle body condition, etc. The vehicle body condition is, for example, the dynamic radius and slip amount of the tire of each wheel W, etc. Fig. 6 is a graph showing an example of the correspondence relationship between the predetermined value α and the vehicle body speed Vv in the vehicle control system 10 of the embodiment. Fig. 7 is a graph showing another example of the correspondence relationship between the predetermined value α and the vehicle body speed Vv in the vehicle control system 10 of the embodiment.

[0042] For example, as shown in FIGS. 6 and 7, when the predetermined value α is a variable value, the traction control unit 11 changes the predetermined value α in accordance with the vehicle speed Vv. For example, the predetermined value α shown in FIG. 6 corresponds to a case where the axle speed thresholds VthL, VthH are set according to the slip ratio, and changes from zero to an increasing trend as the vehicle speed Vv increases from zero. For example, the predetermined value α shown in Fig. 7 corresponds to a case where each axle speed threshold VthL, VthH is set according to the slip amount in the low vehicle speed region and according to the slip ratio in the high vehicle speed region. The predetermined value α shown in Fig. 7 is a predetermined constant value α0 when the vehicle body speed Vv is equal to or less than the predetermined threshold value Vva, and changes to an increasing trend from the predetermined constant value α0 as the vehicle body speed Vv increases from the predetermined threshold value Vva.

[0043] As described above, the vehicle control system 10 of the embodiment includes the traction control unit 11 that sets the axle speed threshold Vth between the target axle speed Vw and the vehicle body speed Vv. This allows each motor control unit 15, 17 to quickly terminate the predetermined torque control when the slippage of each wheel W is resolved or reduced to an acceptable level, without needing the vehicle body speed Vv to determine whether or not there is slippage of each wheel W. For example, by preventing the execution of the predetermined torque control that reduces the torque of the wheel W from being continued for an excessive period, it is possible to appropriately resolve the slippage of each wheel W while suppressing a decrease in acceleration or deceleration and destabilization of vehicle behavior.

[0044] Based on the subtraction value Vsub and addition value Vadd and the minimum axle speed threshold VthL and maximum axle speed threshold VthH during acceleration and deceleration, respectively, an axle speed threshold Vth can be set to determine the end of execution of the specified torque control just before the slip of each wheel W is eliminated or reduced to an acceptable level, thereby enabling the execution of the specified torque control to be terminated quickly and appropriately.

[0045] During acceleration and deceleration, an axle speed threshold Vth can be set based on the target axle speed Vw, the minimum axle speed threshold VthL, and the maximum axle speed threshold VthH to determine whether or not to execute a specified torque control when slippage of each wheel W has been eliminated or is within an acceptable level, and the execution of the specified torque control can be appropriately started and ended when slippage of each wheel W occurs.

[0046] By making the predetermined value α a variable, the traction control unit 11 can properly determine whether the slippage of each wheel W has been eliminated or is within an acceptable level depending on the vehicle body condition, and can properly and accurately improve the responsiveness of the end of execution of the predetermined torque control.

[0047] By configuring the axle speed information to be sent to each motor control unit 15, 17 using the target axle speed Vw and the offset amount ΔV, the traction control unit 11 can suppress an increase in communication volume compared to, for example, configuring the axle speed information using the axle speed threshold Vth instead of the offset amount ΔV.

[0048] (Variation) Modifications of the embodiment will be described below. Note that the same parts as those in the above-described embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified. In the above-described embodiment, the traction control unit 11 sets the first predetermined value for obtaining the subtraction value Vsub when the vehicle accelerates and the second predetermined value for obtaining the addition value Vadd when the vehicle decelerates to the same predetermined initial value ΔV0, but this is not limited to this, and the first predetermined value and the second predetermined value may be different values ​​from each other. In the above-described embodiment, the traction control unit 11 sets the maximum axle speed threshold VthH during vehicle acceleration and the minimum axle speed threshold VthL during vehicle deceleration using the same predetermined value α, but this is not limited to this, and they may be set using different values ​​instead of the same predetermined value α.

[0049] In the above-described embodiment, an example in which the front motor MF is controlled in response to slippage occurring on the left and right front wheels WF is described in Figures 3, 4 and 5, but this is not limited to this, and similar processing may also be performed, for example, when the rear motor MR is controlled in response to slippage occurring on the left and right rear wheels WR.

[0050] In the above-described embodiment, the vehicle is provided with a front motor MF connected to the left and right front wheels WF and a rear motor MR connected to the left and right rear wheels WR, but is not limited to this. For example, each wheel W may be provided with an individual rotating electric machine M, or an appropriate combination of multiple wheels W may be provided with an individual rotating electric machine M.

[0051] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0052] 10...vehicle control system, 11...traction control unit, 13...wheel torque control unit, 15...front motor control unit (rotating electric machine control unit), 17...rear motor control unit (rotating electric machine control unit), 19...meter, M...rotating electric machine, MF...front motor (rotating electric machine), MR...rear motor (rotating electric machine), W...wheel (drive wheel), WF...front wheel (drive wheel), WR...rear wheel (drive wheel).

Claims

1. a traction control unit that controls the traction of the drive wheels; a rotating electric machine control unit that controls the operation of the rotating electric machine that exchanges torque with the drive wheels based on information input from the traction control unit; Equipped with The traction control unit includes: an axle speed threshold for determining the end of execution of a predetermined torque control executed by the rotary electric machine control unit to eliminate slippage of the drive wheels is set between a target axle speed and a vehicle body speed, and the information regarding the axle speed threshold is output to the rotary electric machine control unit; The axle speed threshold during acceleration is set to the larger of a value obtained by subtracting a first predetermined value from the target axle speed or a predetermined lower threshold. Vehicle control system.

2. a traction control unit that controls the traction of the drive wheels; a rotating electric machine control unit that controls the operation of the rotating electric machine that exchanges torque with the drive wheels based on information input from the traction control unit; Equipped with The traction control unit includes: an axle speed threshold for determining the end of execution of a predetermined torque control executed by the rotary electric machine control unit to eliminate slippage of the drive wheels is set between a target axle speed and a vehicle body speed, and the information regarding the axle speed threshold is output to the rotary electric machine control unit; The axle speed threshold during deceleration is set to the smaller of a value obtained by adding a second predetermined value to the target axle speed or a predetermined upper threshold. Vehicle control system.

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