Vehicle control system

Abstract

The invention provides a vehicle control system capable of suppressing reduction of acceleration or deceleration and instability of vehicle behavior and suitably eliminating slip. A vehicle control system includes a traction control unit, a front motor control unit, and a rear motor control unit. The traction control unit controls the traction of each of the plurality of wheels. Each motor control unit controls each of a plurality of rotating electrical machines that transmit and receive torque to and from a plurality of wheels on the basis of axle speed information input from a traction control unit. The traction control unit sets an axle speed threshold value between a target axle speed and a vehicle body speed, the axle speed threshold value being used to determine whether or not a predetermined torque control performed by each motor control unit in order to eliminate slippage of each wheel needs to be executed, and outputs axle speed information relating to the axle speed threshold value to each motor control unit.

Description

Technical Field

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

[0002] In recent years, efforts to provide sustainable transportation systems that take into account vulnerable people such as the elderly, the disabled, and children among traffic participants have been active. To achieve this, research and development efforts are focused on further improving traffic safety and convenience through development related to vehicle behavior stability.

[0003] Conventionally, there is known a traction control device that reduces the torque of a motor as a power source to eliminate slip when a drive wheel slips, and suppresses the wheel speed variation of the drive wheel and the acceleration variation in the front-rear direction of the vehicle by using the slip rate of only the region of the drive wheel where the lateral stiffness is high (for example, see Patent Document 1 below).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-115644 Summary of the invention

[0005] In addition, in the behavior stability of a vehicle, when wheel slip occurs during acceleration or deceleration, a problem is to eliminate the slip while suppressing a decrease in acceleration or deceleration and destabilization of the vehicle behavior.

[0006] For example, the above-mentioned conventional traction control device does not disclose the slip rate threshold used for canceling the execution of the traction control, and may not be able to quickly stop the traction control when the slip is eliminated. For example, when the slip is eliminated rapidly due to a change in the road friction state such as a change from a snowy road surface to an asphalt road surface during vehicle acceleration, appropriate acceleration may not be achieved due to the delay in the stop responsiveness of the traction control.

[0007] The solution involved in the present invention is made in consideration of such a situation, and its object is to provide a vehicle control system that can suppress the decrease in acceleration or deceleration and the instability of vehicle behavior and appropriately eliminate slip, and further contribute to the development of a sustainable transportation system.

[0008] In order to solve the above-mentioned problems and achieve the related objects, the present invention adopts the following means.

[0009] (1): A vehicle control system according to one embodiment of the present invention comprises: a traction control unit that controls traction of drive wheels; and a rotating electric machine control unit that controls the operation of the rotating electric machine that transfers torque to and from the drive wheels based on information input from the traction control unit, wherein the traction control unit sets an axle speed threshold between a target axle speed and a vehicle body speed, and outputs the information related to the axle speed threshold to the rotating electric machine control unit, wherein the axle speed threshold is used to determine whether execution of a prescribed torque control performed by the rotating electric machine control unit to eliminate slip of the drive wheels has been terminated.

[0010] (2): Based on the above scheme (1), the traction control unit may set the axle speed threshold during acceleration to the larger of a value obtained by subtracting a first specified value from the target axle speed and a specified lower threshold, and the traction control unit may set the axle speed threshold during deceleration to the smaller of a value obtained by adding a second specified value to the target axle speed and a specified upper threshold.

[0011] (3): Based on the above scheme (2), the rotating motor control unit may set the axle speed threshold value during acceleration to be the same as the target axle speed when the target axle speed during acceleration is smaller than the prescribed lower threshold value, and the rotating motor control unit may set the axle speed threshold value during deceleration to be the same as the target axle speed when the target axle speed during deceleration is larger than the prescribed upper threshold value.

[0012] (4) In the above configuration (2) or (3), the traction control unit may set the predetermined lower threshold and the predetermined upper threshold based on a vehicle body state.

[0013] According to the above-mentioned solution (1), the traction control unit is provided with a traction control unit that sets the axle speed threshold between the target axle speed and the vehicle body speed. Therefore, the rotating electric machine control unit does not need the vehicle body speed for determining whether the drive wheel is slipping. When the slipping of the drive wheel is eliminated or converged to an allowable degree, the specified torque control can be quickly terminated. For example, the specified torque control for reducing the torque of the drive wheel is suppressed from being continuously executed for an excessive period, thereby suppressing the reduction of acceleration or deceleration and the instability of vehicle behavior and appropriately eliminating the slipping of the drive wheel.

[0014] In the case of the above scheme (2), the axle speed threshold for determining when the drive wheel slip is about to be eliminated or converged to an allowable level and the execution of the prescribed torque control is terminated can be set during acceleration and deceleration, respectively, so that the execution of the prescribed torque control can be terminated quickly and appropriately.

[0015] In the case of the above scheme (3), the axle speed thresholds for determining whether it is necessary to execute the prescribed torque control in a state where the drive wheel slip is eliminated or converged to an allowable degree can be set during acceleration and deceleration respectively, and the start and end of the execution of the prescribed torque control can be appropriately implemented when drive wheel slip occurs.

[0016] In the case of the above-mentioned means (4), it is possible to appropriately determine whether the slip of the drive wheel has been eliminated or has converged to an allowable level according to the vehicle body state, and the responsiveness of the termination of the execution of the prescribed torque control can be improved appropriately and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a block diagram showing the functional configuration of a vehicle control system in the embodiment of the present invention.

[0018] Figure 2 This is a flowchart showing the operation of the vehicle control system in the embodiment of the present invention.

[0019] Figure 3 This is a diagram showing an example of the correspondence relationship among the axle speed, target axle speed, axle speed threshold, vehicle body speed, operation flag, and offset amount during vehicle acceleration in the vehicle control system according to the embodiment of the present invention.

[0020] Figure 4 This is a diagram showing an example of the correspondence relationship among the target axle speed, the axle speed threshold, the minimum axle speed threshold, the vehicle body speed, and the offset amount during vehicle acceleration in the vehicle control system according to the embodiment of the present invention.

[0021] Figure 5 This is a diagram showing an example of the correspondence relationship among the target axle speed, the axle speed threshold, the maximum axle speed threshold, the vehicle body speed, and the offset amount during vehicle deceleration in the vehicle control system according to the embodiment of the present invention.

[0022] Figure 6 This is a diagram showing an example of the correspondence relationship between the prescribed value and the vehicle body speed in the vehicle control system according to the embodiment of the present invention.

[0023] Figure 7 This is a diagram showing another example of the correspondence relationship between the prescribed value and the vehicle body speed in the vehicle control system according to the embodiment of the present invention. DETAILED DESCRIPTION

[0024] Hereinafter, a vehicle control system according to an embodiment of the present invention will be described with reference to the drawings.

[0025] Figure 1 : is a block diagram showing the functional structure of the vehicle control system 10 in the embodiment.

[0026] The vehicle control system 10 of the embodiment is mounted on an electric vehicle (vehicle) such as an electric vehicle, a hybrid vehicle, and 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.

[0027] The vehicle control system 10 in the embodiment controls, for example, an electric vehicle equipped with a plurality of rotating motors M that transfer torque to and from a plurality of wheels W, and a reporting device that presents various information to the driver. The rotating motor M is, for example, a three-phase AC brushless DC motor. The rotating motor M generates a driving torque on the wheels W by performing a power operation using the power supplied from a power conversion device or the like. The rotating motor M generates a generated power and generates a braking torque on the wheels W by performing a regenerative operation using the rotational power input from the wheels W side. The rotating motor 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.

[0028] like Figure 1 As shown, 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 .

[0029] Each control unit 11, 13, 15, 17 is a software function unit that performs its function by executing a predetermined program by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU having an electronic circuit such as a processor such as a CPU, a ROM (Read Only Memory) for storing programs, a RAM (Random Access Memory) for temporarily storing data, and a timer. At least a part of each control unit 11, 13, 15, 17 may also be an integrated circuit such as an LSI (Large Scale Integration).

[0030] Each of the control units 11, 13, 15, and 17 obtains signals of detection values ​​outputted from various sensors. The various sensors include, for example, an operation amount sensor for detecting whether or not the driver has operated the accelerator operating member and the brake operating member, and the operation amount of the accelerator operating member and the brake operating member by the driver, a current sensor for detecting the current of the rotating electric machine M, a voltage sensor for detecting the voltage of the rotating electric machine M, a rotation angle sensor for detecting the rotation angle of the rotating electric machine M, an acceleration sensor for detecting the acceleration of the vehicle, and a wheel speed sensor for detecting the rotation speed (wheel speed) of each wheel W of the vehicle.

[0031] The traction control unit 11 is a part of a device that suppresses abrupt changes in vehicle behavior and stabilizes the vehicle's posture, such as a so-called TCS (Traction Control System). The traction control unit 11 suppresses slippage (so-called sliding) of the driving wheels on a slippery road surface, etc., and ensures desired driving force, braking force, and steering ability.

[0032] For example, the traction control unit 11 controls the traction of each of the plurality of wheels W by setting a target axle speed Vw and an axle speed threshold value Vth for each of the plurality of rotating electrical machines M. The traction control unit 11 sets a target axle speed Vw and an axle speed threshold value Vth for each of the front motor MF that transmits and receives torque to the left and right front wheels WF of the vehicle and the rear motor MR that transmits and receives torque to the left and right rear wheels WR of the vehicle.

[0033] The traction control unit 11 sets the target axle speed Vw and the axle speed threshold value Vth as threshold values ​​for determining whether or not it is necessary to execute the predetermined torque control executed by the front motor control unit 15 and the rear motor control unit 17, which will be described later. The predetermined torque control is, for example, a process of controlling the torque of each rotary electric machine M in order to eliminate the slip of the wheels W as the drive wheels. The traction control unit 11 sets the target axle speed Vw as an intervention threshold value for determining the start of the execution of the predetermined torque control, and sets the axle speed threshold value Vth as an exit threshold value for determining the end of the execution of the predetermined torque control.

[0034] The traction control unit 11 sets the axle speed threshold value Vth between the target axle speed Vw and the vehicle body speed Vv, for example. The traction control unit 11 obtains signals of detection values ​​output from the acceleration sensor and the wheel speed sensor, and obtains the vehicle speed (vehicle body speed) Vv by a predetermined calculation or map search based on the acceleration and the wheel speed. The traction control unit 11 sets a predetermined offset ΔV as information related to the axle speed threshold value Vth, for example. For example, the axle speed threshold value Vth when the vehicle is accelerating is set by subtracting the offset ΔV from the target axle speed Vw (Vth=Vw-ΔV), and the axle speed threshold value Vth when the vehicle is decelerating is set by adding the offset ΔV to the target axle speed Vw (Vth=Vw+ΔV).

[0035] The traction control unit 11 transmits axle speed information including a target axle speed Vw and a predetermined offset ΔV as 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, for example. The traction control unit 11 receives information indicating an operating state of a predetermined torque control, which is transmitted from each of the front motor control unit 15 and the rear motor control unit 17, which will be described later, for example.

[0036] The traction control unit 11 obtains the vehicle state through a predetermined estimation process based on various information obtained from the outside, such as information indicating the operation state of the predetermined torque control. The traction control unit 11 instructs a meter 19 described later to report whether the predetermined torque control is in operation or stopped.

[0037] The wheel torque control unit 13 controls the torque transmission to each wheel W of the vehicle, as in so-called AWD (All Wheel Drive). The wheel torque control unit 13 optimizes the torque distribution to the front, rear, left, and right wheels W in various driving conditions such as acceleration, deceleration, and turning of the vehicle, to ensure desired driving stability.

[0038] For example, the wheel torque control unit 13 sets a required torque for each of the plurality of rotating electrical machines M according to the torque required by the driver through the accelerator operation or the brake operation of the driver of the vehicle, thereby controlling the torque distributed to each of the plurality of wheels W. 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 on the required torque by communicating with each of the front motor control unit 15 and the rear motor control unit 17 described later.

[0039] Each of the front motor control unit 15 and the rear motor control unit 17 includes, for example, 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 and 17 controls the power transfer between the front motor MF and the rear motor MR through a power conversion device composed of, for example, a plurality of switching elements. Each of the motor control units 15 and 17 generates a rotational driving force by sequentially reversing the power supply to the three-phase stator winding of the rotating electric machine M during the power running operation of the rotating electric machine M (each motor MF and MR). Each of the motor control units 15 and 17 converts the three-phase AC power input from the three-phase stator winding into DC power by switching the phases in synchronization with the rotation of the rotating electric machine M during the regenerative operation of the rotating electric machine M (each motor MF and MR).

[0040] The motor control units 15 and 17 perform feedback control on the rotation speed and torque of the rotary electric machine M (the motors MF and 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 detection values ​​input from various sensors.

[0041] Each motor control unit 15, 17 obtains, for example, the detected value of the rotation speed of each rotary electric machine M output from the rotation angle sensor, and obtains the axle speed Vs in the speed dimension based on the rotation speed of each rotary electric machine M. Each motor control unit 15, 17 calculates, for example, the axle speed threshold value Vth based on the target axle speed Vw and the predetermined offset ΔV obtained from the traction control unit 11. As described above, the axle speed threshold value Vth when the vehicle is accelerating is calculated by subtracting the offset ΔV from the target axle speed Vw (Vth=Vw-ΔV), and the axle speed threshold value Vth when the vehicle is decelerating is calculated by adding the offset ΔV to the target axle speed Vw (Vth=Vw+ΔV).

[0042] Each motor control unit 15, 17 determines whether it is necessary to start the specified torque control for eliminating the slip of the wheel W as the driving wheel, for example, based on the comparison between the axle speed Vs and the target axle speed Vw. Each motor control unit 15, 17 determines whether it is necessary to end the execution of the specified torque control, for example, based on the comparison between the axle speed Vs and the axle speed threshold value Vth.

[0043] The meter 19 is a part of the reporting device mounted on the vehicle. The meter 19 reports various information based on the command signals input from the control units 11, 13, 15, and 17. For example, the meter 19 reports information indicating that the predetermined torque control performed by the motor control units 15 and 17 is in operation or stopped by flashing a lamp.

[0044] Hereinafter, an operation example of the vehicle control system 10 in the embodiment will be described.

[0045] Figure 2 The flowchart shows the operation of the traction control unit 11 in the operation of the vehicle control system 10 according to the embodiment. The traction control unit 11 repeatedly executes the operation according to a predetermined cycle, for example. Figure 2 A series of processing from step S01 to step S04 is shown.

[0046] like Figure 2 As shown, first, the traction control unit 11 obtains the detection values ​​of acceleration and wheel speed output from the acceleration sensor and the wheel speed sensor, and obtains the vehicle body speed Vv by a predetermined calculation or map search based on the acceleration and wheel speed (step S01).

[0047] Next, the traction control unit 11 sets a target axle speed Vw, and sets an axle speed threshold value Vth between the target axle speed Vw and the vehicle body speed Vv (step S02 ).

[0048] Next, the traction control unit 11 sets a predetermined offset amount ΔV according to the axle speed threshold value Vth during each of acceleration and deceleration of the vehicle (step S03 ).

[0049] 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 and 17 (step S04 ). Then, the traction control unit 11 advances the processing to the end.

[0050] Hereinafter, the operation examples of the vehicle control system 10 in the embodiment when the vehicle is accelerated and when the vehicle is decelerated will be described. Figure 3 , Figure 4 and Figure 5 8 is a description of an example of controlling the front motor MF in response to a situation in which, for example, the left and right front wheels WF slip.

[0051] Figure 3 1 is a diagram showing an example of the correspondence relationship among the axle speed Vs, the target axle speed Vw, the axle speed threshold Vth, the vehicle body speed Vv, the activation flag, and the offset ΔV during vehicle acceleration in the vehicle control system 10 according to the embodiment. Figure 4 1 is a diagram showing an example of the correspondence relationship among the target axle speed Vw, the axle speed threshold Vth, the minimum axle speed threshold VthL, the vehicle body speed Vv, and the offset ΔV during vehicle acceleration in the vehicle control system 10 according to the embodiment.

[0052] exist Figure 3 and Figure 4 When the vehicle is accelerating as shown, the traction control unit 11 sets the larger of, for example, a value obtained by subtracting the first predetermined value from the target axle speed Vw (subtraction value Vsub) and a predetermined lower threshold value as the axle speed threshold value Vth. The traction control unit 11 sets, for example, a predetermined initial value ΔV0 of the offset ΔV as the first predetermined value. The traction control unit 11 sets, for example, a minimum axle speed threshold value VthL (=Vv+α) obtained by adding a predetermined value α to the vehicle body speed Vv as the predetermined lower threshold value.

[0053] The predetermined lower threshold is, for example, a threshold for the axle speed Vw for determining that the slip of each wheel W is eliminated or converged to an allowable degree when the vehicle is accelerated. The offset ΔV when the vehicle is accelerated is set, for example, in such a manner that at least the axle speed threshold Vth does not fall below the predetermined lower threshold. For example, by setting a minimum axle speed threshold VthL (=Vv+α) for the predetermined lower threshold, the axle speed threshold Vth is always greater than the vehicle body speed Vv even if the target axle speed Vw changes. The predetermined value α is, for example, a value corresponding to the slip amount when it is considered that the slip of each wheel W is eliminated or converged to an allowable degree.

[0054] First, as after time t0 , for example, as the axle speed Vs increases to or above the vehicle body speed Vv, the traction control unit 11 changes the offset amount ΔV from zero to a predetermined initial value ΔV0 .

[0055] Next, as the axle speed Vs increases to or above the target axle speed Vw, for example, after time t1, the front motor control unit 15 changes the flag value of the operation flag from zero to "1", thereby starting execution of the predetermined torque control for eliminating the slip of the front wheels WF.

[0056] When, for example, the subtraction value Vsub (=Vw-ΔV0) is larger than the minimum axle speed threshold value VthL (=Vv+α) as in 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 value Vth.

[0057] Next, as at time t2 or later, for example, the subtraction value Vsub (=Vw-ΔV0) decreases to or below the minimum axle speed threshold value VthL (=Vv+α), and the minimum axle speed threshold value VthL (=Vv+α) increases toward the target axle speed Vw, and the traction control unit 11 changes the offset amount ΔV from the predetermined initial value ΔV0 toward zero to reduce the tendency change. The traction control unit 11 sets the minimum axle speed threshold value VthL (=Vv+α) as the axle speed threshold value Vth.

[0058] Next, as after time t3, for example, as the target axle speed Vw decreases to or below the minimum axle speed threshold VthL (=Vv+α), the traction control unit 11 sets the offset ΔV to zero. The traction control unit 11 sets the target axle speed Vw to the axle speed threshold Vth.

[0059] Next, as after time t4, for example, as the axle speed Vs decreases below the axle speed threshold Vth (= target axle speed Vw), the front motor control unit 15 changes the flag value of the working flag from "1" to zero, thereby setting the end of execution of the prescribed torque control for eliminating the slip of the front wheels WF.

[0060] Figure 5 1 is a diagram showing an example of the correspondence relationship among the target axle speed Vw, the axle speed threshold Vth, the maximum axle speed threshold VthH, the vehicle body speed Vv, and the offset ΔV during vehicle deceleration in the vehicle control system 10 according to the embodiment.

[0061] In such Figure 5When the vehicle decelerates as shown, the traction control unit 11 sets the smaller of, for example, a value obtained by adding the second predetermined value to the target axle speed Vw (addition value Vadd) and a predetermined upper threshold value as the axle speed threshold value Vth. The traction control unit 11 sets, for example, a predetermined initial value ΔV0 of the offset ΔV as the second predetermined value. The traction control unit 11 sets, for example, a maximum axle speed threshold value VthH (=Vv-α) obtained by subtracting a predetermined value α from the vehicle body speed Vv as the predetermined upper threshold value.

[0062] The prescribed upper threshold is, for example, a threshold for the axle speed Vw for determining that the slip of each wheel W is eliminated or converged to an allowable degree when the vehicle is decelerating. The offset ΔV when the vehicle is decelerating is, for example, set in such a manner that at least the axle speed threshold Vth does not exceed the prescribed upper threshold. For example, by setting a maximum axle speed threshold VthH (=Vv-α) for the prescribed upper threshold, the axle speed threshold Vth is always smaller than the vehicle body speed Vv even if the target axle speed Vw changes. The prescribed value α is, for example, a value corresponding to the slip amount when it is considered that the slip of each wheel W is eliminated or converged to an allowable degree.

[0063] First, as after time t0, for example, as the axle speed Vs (not shown) decreases to be equal to or lower than the vehicle body speed Vv, the traction control unit 11 changes the offset amount ΔV from zero to a predetermined initial value ΔV0.

[0064] Next, as after time t11, for example, as the axle speed Vs (not shown) decreases to below the target axle speed Vw, the front motor control unit 15 changes the flag value of the working flag (not shown) from zero to "1", thereby setting the start of execution of the prescribed torque control for eliminating the slip of the front wheel WF.

[0065] For example, when the addition value Vadd (=Vw+ΔV0) is smaller than the maximum axle speed threshold value VthH (=Vv-α) as in the period from time t0 to time t12, the traction control unit 11 sets the addition value Vadd (=Vw+ΔV0) as the axle speed threshold value Vth.

[0066] Next, as at time t12 or later, for example, the added value Vadd (=Vw+ΔV0) increases to be equal to or larger than the maximum axle speed threshold value VthH (=Vv-α), and the maximum axle speed threshold value VthH (=Vv-α) decreases toward the target axle speed Vw, and accordingly, the traction control unit 11 changes the offset amount ΔV from the predetermined initial value ΔV0 toward zero to decrease the tendency. The traction control unit 11 sets the maximum axle speed threshold value VthH (=Vv-α) as the axle speed threshold value Vth.

[0067] Next, as after time t13, for example, as the target axle speed Vw increases to or above the maximum axle speed threshold VthH (=Vv-α), the traction control unit 11 sets the offset ΔV to zero. The traction control unit 11 sets the target axle speed Vw to the axle speed threshold Vth.

[0068] Moreover, for example, as the axle speed Vs (not shown) increases to above the axle speed threshold Vth (= target axle speed Vw), the front motor control unit 15 changes the flag value of the working flag (not shown) from "1" to zero, thereby setting the end of execution of the prescribed torque control for eliminating slip of the front wheel WF.

[0069] In the above Figure 3 , Figure 4 and Figure 5 In the example shown, the traction control unit 11 sets the predetermined value α for setting each of the minimum axle speed threshold value VthL (=Vv+α) and the maximum axle speed threshold value VthH (=Vv-α) to a fixed value or a variable value that changes according to the vehicle body state, etc. The vehicle body state is, for example, the movement radius and slip amount of the tire of each wheel W.

[0070] Figure 6 : is a line 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 according to the embodiment. Figure 7 : is a diagram showing another example of the correspondence relationship between the predetermined value α and the vehicle body speed Vv in the vehicle control system 10 according to the embodiment.

[0071] For example Figure 6 and Figure 7 As shown, when the predetermined value α is set as a variable value, the traction control unit 11 changes the predetermined value α according to the vehicle body speed Vv.

[0072] About e.g. Figure 6 The prescribed value α shown corresponds to the case where the axle speed threshold values ​​VthL and VthH are set according to the slip rate, and changes from zero in an increasing trend as the vehicle body speed Vv increases from zero.

[0073] For example Figure 7 The specified value α shown corresponds to the case where each axle speed threshold value VthL, VthH is set according to the slip amount in the low vehicle speed range, and each axle speed threshold value VthL, VthH is set according to the slip rate in the high vehicle speed range. Figure 7 The prescribed value α shown is a prescribed constant value α0 when the vehicle body speed Vv is equal to or lower than a prescribed threshold value Vva, and changes in an increasing tendency from the prescribed constant value α0 as the vehicle body speed Vv increases from the prescribed threshold value Vva.

[0074] As described above, according to the vehicle control system 10 of the embodiment, the traction control unit 11 is provided to set the axle speed threshold value Vth between the target axle speed Vw and the vehicle body speed Vv, so that each motor control unit 15, 17 does not need the vehicle body speed Vv for determining whether each wheel W is slipping, and can quickly end the prescribed torque control when the slip of each wheel W is eliminated or converged to an allowable degree. For example, the prescribed torque control for reducing the torque of the wheel W is suppressed from being continuously executed for an excessive period, so that the reduction in acceleration or deceleration and the instability of vehicle behavior can be suppressed and the slip of each wheel W can be appropriately eliminated.

[0075] The axle speed threshold Vth for determining when the slip of each wheel W is about to be eliminated or converged to an allowable level can be set based on the subtraction value Vsub and the addition value Vadd, as well as the minimum axle speed threshold VthL and the maximum axle speed threshold VthH during acceleration and deceleration, respectively, to terminate the execution of the prescribed torque control, thereby quickly and appropriately terminating the execution of the prescribed torque control.

[0076] The axle speed threshold Vth for determining whether it is necessary to execute the prescribed torque control for eliminating the slip of each wheel W or converging to an allowable degree can be set based on the target axle speed Vw, the minimum axle speed threshold VthL and the maximum axle speed threshold VthH during acceleration and deceleration, respectively. When slip of each wheel W occurs, the start and end of the execution of the prescribed torque control can be appropriately implemented.

[0077] By setting the predetermined value α as a variable value, the traction control unit 11 can appropriately determine whether the slip of each wheel W has been eliminated or converged to an allowable level according to the vehicle body state, and can appropriately and accurately improve the responsiveness of the end of execution of the predetermined torque control.

[0078] The traction control unit 11 configures the axle speed information sent to the motor control units 15 and 17 with the target axle speed Vw and the offset ΔV, thereby suppressing an increase in communication volume compared to, for example, a case where the axle speed information is configured with the axle speed threshold Vth instead of the offset ΔV.

[0079] (Variation Example)

[0080] The following describes a modification of the embodiment. The same reference numerals are used for the same parts as those in the above-mentioned embodiment, and the description thereof will be omitted or simplified.

[0081] In the above-mentioned embodiment, the traction control unit 11 sets the first prescribed value for obtaining the subtraction value Vsub when the vehicle is accelerating and the second prescribed value for obtaining the addition value Vadd when the vehicle is decelerating to the same prescribed initial value ΔV0, but is not limited to this, and the first prescribed value and the second prescribed value may also be set to different values.

[0082] In the above embodiment, the traction control unit 11 sets the maximum axle speed threshold value VthH during vehicle acceleration and the minimum axle speed threshold value VthL during vehicle deceleration by the same predetermined value α. However, the present invention is not limited to this. Instead of the same predetermined value α, different values ​​may be used to set the maximum axle speed threshold value VthH during vehicle acceleration and the minimum axle speed threshold value VthL during vehicle deceleration.

[0083] In the above-mentioned embodiment, Figure 3 , Figure 4 and Figure 5 , an example of controlling the front motor MF in response to slippage of the left and right front wheels WF is described, but the present invention is not limited to this. For example, the same processing can be performed when controlling the rear motor MR in response to slippage of the left and right rear wheels WR.

[0084] In the above-mentioned embodiment, the vehicle includes 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 the present invention is not limited thereto. For example, each wheel W may be provided with a rotating electric machine M alone, or a suitable combination of a plurality of wheels W may be provided with a rotating electric machine M alone.

[0085] The embodiments of the present invention are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are included in the invention and its equivalent scope as included in the scope and purpose of the invention.

Claims

1. A vehicle control system, wherein: The vehicle control system comprises: a traction control unit that controls the traction of the drive wheels; and a rotating electric machine control unit that controls the operation of the rotating electric machine that exchanges torque with the drive wheel based on the information input from the traction control unit, The traction control unit sets an axle speed threshold between a target axle speed and a vehicle body speed, and outputs the information related to the axle speed threshold to the rotating electric machine control unit. The axle speed threshold is used to determine the end of execution of a prescribed torque control performed by the rotating electric machine control unit to eliminate slip of the drive wheel.

2. The vehicle control system according to claim 1, wherein: The traction control unit sets the axle speed threshold value during acceleration to the larger of a value obtained by subtracting a first predetermined value from the target axle speed and a predetermined lower threshold value, The traction control unit sets the axle speed threshold value during deceleration to the smaller of a value obtained by adding a second predetermined value to the target axle speed and a predetermined upper threshold value.

3. The vehicle control system according to claim 2, wherein: The rotary electric machine control unit sets the axle speed threshold value during acceleration to be the same as the target axle speed when the target axle speed during acceleration is lower than the predetermined lower threshold value, The rotating electrical machine control section sets the axle speed threshold value during deceleration to be the same as the target axle speed when the target axle speed during deceleration is greater than the predetermined upper threshold value.

4. The vehicle control system according to claim 2 or 3, wherein: The traction control unit sets the predetermined lower threshold value and the predetermined upper threshold value based on a vehicle body state.

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