WO2019017357A1

WO2019017357A1 - Vehicle-driving-torque control device

Info

Publication number: WO2019017357A1
Application number: PCT/JP2018/026787
Authority: WO
Inventors: 敏藤末; 佑介竹谷
Original assignee: 株式会社アドヴィックス
Priority date: 2017-07-18
Filing date: 2018-07-17
Publication date: 2019-01-24
Also published as: JP2019018697A; JP6756310B2

Abstract

A braking control device according to the present invention includes: a driving source that provides a driving wheel with a driving torque for accelerating a vehicle; an actuator that provides a wheel with a braking torque for decelerating the vehicle; a wheel-speed sensor that detects the speed of the wheel of the vehicle; and a controller that computes a demand torque for requesting an increase in the driving torque so as to suppress deceleration slipping of the driving wheel and that controls the driving source on the basis of the demand torque. The controller is configured to compute the amount of slip of the driving wheel on the basis of the speed and to compute the demand torque on the basis of the amount of slip when the actuator is not operating and to determine the demand torque to be a compensation value that does not depend on the amount of slip when the actuator is operating. For example, the compensation value is a preset constant not less than zero.

Description

Vehicle drive torque control device

The present invention relates to a drive torque control device for a vehicle.

According to Patent Document 1, for the purpose of "effectively suppressing the influence of the brake torque of the drive source on the brake control", it acts on the left and right front wheels driven by the output of the engine and the wheels according to the state of the vehicle. It is described that "a hydraulic unit for controlling the braking force and a control unit for controlling the hydraulic unit are provided, and the brake torque of the engine is reduced when the hydraulic unit applies the braking force to the engine."

Specifically, it is determined whether "ABS control (also referred to as" anti-skid control ") is being performed. If the anti-skid control is not being performed, the engine torque request value (the target engine torque for reducing the engine brake torque) is determined to be "none". It is described that the engine torque request value is determined to "0 Nm" (see Example 1) if the anti-skid control is in the affirmative.

Also, as in the above case, when the anti-skid control is under execution is denied, the engine torque request value is determined to be "none". However, at the time of anti-skid control, the drive wheel average speed is determined, and this value is compared with the target slip ratio speed to which the offset value is added or subtracted. When it is determined that the slip is too small, the engine torque request value is set as the engine brake torque according to the difference between the target slip rate speed and the average speed of the driving wheel. Conversely, when it is determined that the slip is excessive, the engine torque request value is set as an acceleration torque according to the difference between the driving wheel average speed and the target slip ratio speed.

By the way, the engine brake is a braking action that occurs when the accelerator pedal is released and the output of the engine is reduced. When the engine output is reduced from the state where the engine output and the traveling resistance are balanced (that is, the constant speed traveling state) while the vehicle is traveling, mechanical friction loss of the engine, pumping loss (fluid resistance of intake and exhaust) The accessory drive loss or the like acts as a drag of the engine, and a decelerating force (that is, a braking force of wheels) is generated in the vehicle to act as an engine brake. Furthermore, not only the engine but also the resistance (friction loss etc.) by the power transmission mechanism such as the transmission, the drive shaft, etc. are factors that generate the braking force on the wheels.

In the device described in Patent Document 1, the engine brake is compensated when performing antiskid control, but not compensated when antiskid control is not implemented. For example, on a road surface with a very low coefficient of friction (such as a frozen road), it may happen that the deceleration slip of the wheel becomes excessive only by the engine brake. Even in such a situation, it is desirable that the wheel slip be properly suppressed.

Further, in the torque applied to the wheel, the responsiveness differs between the drive source (engine) and the braking device. That is, the generation of the driving torque due to the driving source is relatively slow, and the generation of the braking torque by the braking device is relatively fast. For this reason, when the driving torque is increased or decreased according to the wheel slip state during antiskid control controlled based on the wheel slip, there is a concern about interference with the antiskid control. During anti-skid control, the control interference must be avoided.

JP, 2010-018147, A

Based on the above, the object of the present invention is to prevent the reduction slip caused by the drive source etc. from being compensated at all times not only during braking but also at all times, and interference with braking control such as anti-skid control is reliably avoided. It is to provide what you get.

The braking control device for a vehicle according to the present invention comprises a drive source (PW) for applying a drive torque (Dq) for accelerating the vehicle (VH) to the drive wheels (WD), and a braking torque (decelerating the vehicle (VH) An actuator (BR) for applying Bq) to the wheel (WH), a wheel speed sensor (VW) for detecting the speed (Vw) of the wheel (WH) of the vehicle (VH), and deceleration of the drive wheel (WD) A controller (ECU) that calculates a required torque (Dr) that requires an increase in the drive torque (Dq) so as to suppress slip, and controls the drive source (PW) based on the required torque (Dr) And.

In the braking control device for a vehicle according to the present invention, the controller (ECU) may slip the driving wheel (WD) based on the speed (Vw) when the actuator (BR) is not operating. (Sl) is calculated, the required torque (Dr) is calculated based on the slip amount (Sl), and when the actuator (BR) is operating, the required torque (Dr) is calculated as the slip It is configured to determine a compensation value (db) that does not depend on the quantity (Sl). For example, a preset constant of “0 (zero)” or more is adopted as the compensation value (db).

According to the above configuration, when the actuator BR is inoperative, the drive torque increase control is executed based on the slip amount Sl. Therefore, excessive deceleration slip due to the drive source PW can be reliably suppressed. On the other hand, when the actuator BR is in operation, drive torque increase control is executed based on the compensation value db which does not depend on the slip amount Sl. As a result, control interference between braking control such as antiskid control and drive torque increase control can be reliably avoided.

1 is an overall configuration diagram of a vehicle equipped with a drive torque control device CS of a vehicle according to the present invention. It is a functional block diagram for explaining arithmetic processing of drive torque increase control. It is a time-series diagram for explaining restriction processing block LS. It is the schematic for demonstrating an effect | action and an effect.

<Overall Configuration of Drive Torque Control Device for Vehicle According to the Present Invention>
The drive torque control device CS according to the present invention will be described with reference to the overall configuration diagram of FIG. In the following description, components having the same symbol, such as “ECU”, etc., arithmetic processing, signals, characteristics, and values have the same functions.

The vehicle VH is provided with a drive source (power unit) PW that generates a drive force, and a transmission (transmission) TR connected to the drive source PW. For example, the drive source PW is an internal combustion engine (so-called engine) or an electric motor. The output (drive torque) Dq of the drive source PW is transmitted to each wheel WH by the transmission TR.

In the vehicle VH equipped with the drive torque control device CS, the drive torque Dq, which is the output of the drive source PW, is transmitted to the four wheels WH. Here, the wheel WH to which the drive torque Dq from the drive source PW is transmitted is referred to as "drive wheel WD". In the vehicle VH, a so-called four-wheel drive system is adopted. That is, all the four wheels WH are drive wheels WD. The driving torque Dq is appropriately distributed and transmitted to the front wheels and the rear wheels. Since the drive source PW and the transmission TR are provided on the front wheel side, the drive torque Dq is transmitted to the drive wheel WD at the rear of the vehicle via the propeller shaft SC.

The drive torque Dq of the front wheels is transmitted to the front left and right drive wheels WD via the front wheel differential gear DZ and the front wheel drive shaft SZ. The drive torque Dq of the rear wheel is transmitted to the rear left and right drive wheels WD via the rear wheel differential gear DK and the rear wheel drive shaft SK. The transmission TR includes a center differential gear DC, and the front wheel drive torque and the rear wheel drive torque are appropriately adjusted according to the traveling state of the vehicle VH. The center differential gear DC is controlled by a controller ECU (shift signal Hs).

The drive source PW (for example, an internal combustion engine) is provided with a throttle sensor TH that detects a throttle opening Th, an injection amount sensor FI that detects a fuel injection amount Fi, and a rotation speed sensor NE that detects a driving rotation speed Ne. Be The transmission (transmission) TR is provided with a gear position sensor GP for detecting a transmission gear ratio (gear position) Gp. The throttle opening degree Th, the fuel injection amount Fi, the drive rotational speed Ne, and the gear position Gp are used to calculate the output (drive torque) from the powertrain (generally called drive source PW and transmission TR) of the vehicle VH. Will be adopted. When the drive source PW is an electric motor for driving, the amount of energization (for example, current value) to the drive source PW is detected. Signals obtained by the respective sensors are input to the controller ECU via a communication bus CM described later.

The vehicle VH includes an acceleration operation member AP, an acceleration operation amount sensor AA, a braking operation member BP, a braking operation amount sensor BA, a wheel speed sensor VW, a longitudinal acceleration sensor GX, a controller ECU, and a braking actuator (simply, “actuator” Also known as BR). Furthermore, the four wheels WH (drive wheels WD) of the vehicle VH are provided with a brake caliper CP, a wheel cylinder WC, a rotating member KT, and a friction member MS. The actuator BR and the wheel cylinder WC are connected via a braking pipe HK.

The acceleration operation member (for example, an accelerator pedal) AP is a member operated by the driver to accelerate the vehicle VH and travel at a constant speed. By operating the acceleration operation member AP, the drive torque (torque for accelerating the vehicle) Dq for the wheel WH is adjusted, and a drive force is generated on the wheel WH.

The acceleration operation amount sensor AA is provided on the acceleration operation member AP. The amount of operation Aa of the acceleration operation member (accelerator pedal) AP by the driver is detected by the acceleration operation amount sensor AA. As the acceleration operation amount sensor AA, at least one of an operation displacement sensor that detects an operation displacement of the acceleration operation member AP and an operation force sensor that detects an operation force of the acceleration operation member AP is employed. That is, at least one of the operation displacement of the acceleration operation member AP and the operation force of the acceleration operation member AP is detected as the acceleration operation amount Aa by the acceleration operation amount sensor AA. The acceleration operation amount Aa is input to the controller ECU (in particular, the drive controller ECP).

The brake operation member (for example, the brake pedal) BP is a member operated by the driver to decelerate the vehicle VH. By operating the braking operation member BP, the braking torque Bq for the wheel WH is adjusted, and a braking force is generated on the wheel WH.

A braking operation amount sensor BA is provided on the braking operation member BP. The amount of operation Ba of the brake operation member (brake pedal) BP by the driver is detected by the brake operation amount sensor BA. Among the brake operation amount sensor BA, a hydraulic pressure sensor that detects the pressure of the master cylinder MC, an operation displacement sensor that detects an operation displacement of the brake operation member BP, and an operation force sensor that detects an operation force of the brake operation member BP. At least one of is adopted. That is, at least one of the pressure of the master cylinder MC, the operation displacement of the braking operation member BP, and the operation force of the braking operation member BP is detected by the braking operation amount sensor BA as the braking operation amount Ba. The braking operation amount Ba is input to the controller ECU (in particular, the braking controller ECB).

A braking operation switch BS is provided on the braking operation member BP. The braking operation switch BS detects the presence or absence of the operation of the braking operation member BP by the driver. When the braking operation member BP is not operated (that is, when not braking), the braking operation switch BS outputs an off signal as the operation signal Bs. On the other hand, when the braking operation member BP is operated (ie, at the time of braking), an ON signal is output as the operation signal Bs. The braking operation signal Bs is input to a controller ECU (in particular, a braking controller ECB).

A wheel cylinder WC is provided in the brake caliper (also simply referred to as "caliper") CP. By adjusting (increasing or decreasing) the hydraulic pressure in the wheel cylinder WC of the caliper CP, the piston in the wheel cylinder WC is moved (advanced or retracted) with respect to the rotating member KT. By the movement of the piston, the friction member (for example, the brake pad) MS is pressed against the rotating member KT, and a pressing force is generated. The rotating member KT and the wheel WH are fixed so as to rotate integrally. Therefore, a braking torque Bq (as a result, a braking force) is generated on the wheel WH by the frictional force generated by the pressing force.

Each of the wheels WH of the vehicle VH is provided with a wheel speed sensor VW. The four wheel speed sensors VW detect the speeds Vw of the four wheels. The wheel speed Vw is input to a controller ECU (in particular, a braking controller ECB).

A longitudinal acceleration sensor GX is provided on the vehicle body (spring upper portion) of the vehicle VH. The longitudinal acceleration sensor GX detects a vehicle acceleration (also referred to as “longitudinal acceleration”) Gx in the longitudinal direction (forward direction) of the vehicle VH. For example, the vehicle body acceleration Gx is represented by a positive (plus) value when the vehicle VH is accelerating in the forward direction, and a negative (minus) value when the vehicle VH is decelerating in the forward direction.

The controller (also referred to as “electronic control unit”) ECU is configured of an electric circuit board on which a microprocessor or the like is mounted, and a control algorithm programmed in the microprocessor. The controller ECU includes a controller ECB (also referred to as "brake controller") for the braking actuator BR, a controller ECP (also referred to as "drive controller") for the drive source PW, and a controller ECT ("gear shift controller") for the transmission TR. Also included). The brake controller ECB, the drive controller ECP, and the shift controller ECT are connected by a communication bus CM so that information such as a sensor signal and an internal calculation value may be shared. In other words, the controller ECU is a generic name of the braking controller ECB, the drive controller ECP, and the shift controller ECT.

The controller ECU (in particular, the braking controller ECB) reduces excessive deceleration slip (slip in the wheel rotational direction) of the wheel WH based on the detection signal (wheel speed) Vw of the wheel speed sensor VW, and tends to lock the wheel WH. Anti-skid control is performed to prevent Specifically, based on the wheel speed Vw, a deceleration slip amount S1 that represents the deceleration slip degree of each wheel WH is calculated. Then, a braking signal Br for adjusting the fluid pressure in the wheel cylinder WC is calculated based on the reduction slip amount Sl, and is transmitted to the actuator BR.

In the controller ECU (in particular, the drive controller ECP), the drive torque Dq of the drive wheel WD is controlled based on the acceleration operation amount Aa. Based on the drive signal Pw calculated by the controller ECP, the drive source PW is controlled to adjust the drive torque Dq. For example, when the drive source PW is an internal combustion engine, the fuel injection amount Fi and the throttle opening degree Th are controlled based on the drive signal Pw. Further, when the drive source PW is an electric motor, the amount of energization (supply current) to the electric motor is controlled based on the drive signal Pw.

Further, in the controller ECU, based on the reduction slip amount Sl, control is performed to reduce the resistance by the drive source PW so as to reduce the excessive reduction slip of the drive wheel WD. For example, while the vehicle VH is traveling, when the accelerator pedal is released and the output of the engine is reduced, the drive wheel WD is braked (so-called engine brake). In the constant speed traveling state of the vehicle VH, the engine output (driving torque Dq) and the traveling resistance of the vehicle VH are balanced. From this state, when the engine output is reduced, mechanical friction loss, pumping loss (fluid resistance of intake and exhaust), accessory drive loss, etc. of the engine act as drag (drag torque) of the engine and act on the drive wheel WD. The braking torque Bq acts. In particular, on a road surface with a low coefficient of friction, the braking torque Bq may cause an excessive deceleration slip on the drive wheel WD. In the controller ECU, the output of the drive source PW (that is, the drive torque Dq) is increased so as to suppress such deceleration slip of the drive wheel WD. The control is called "drive torque increase control". For example, in the drive torque increase control, the required torque Dr calculated based on the reduction slip amount Sl in the braking controller ECB is transmitted to the drive controller ECP, and the drive controller ECP achieves the required torque Dr by the drive controller ECP. The drive signal Pw is formed, and the drive source PW is controlled based on the drive signal Pw.

The center differential gear DC is controlled by the controller ECU (in particular, the shift controller ECT) based on the traveling state of the vehicle VH, and the driving force distribution control is executed (that is, the driving torque Dq is the front and rear driving wheels WD). As appropriate). When anti-skid control is not performed, the clutch of the center differential gear DC is engaged, and the four wheels WH of the vehicle VH are drive wheels WD. On the other hand, when anti-skid control is performed, the clutch is brought into the released state, and is brought into a so-called two-wheel drive state.

A braking actuator BR is provided on the vehicle body of the vehicle VH. The actuator BR has a master cylinder MC that generates a braking fluid pressure according to the operating force of the braking operation member (brake pedal) BP, and a hydraulic unit HU that can independently adjust the braking fluid pressure supplied to the wheel cylinder WC. It consists of Master cylinder MC is mechanically connected to brake operation member BP via a brake rod. The master cylinder MC converts the operating force (brake pedal depression force) of the brake operating member BP into the pressure of the braking fluid. A hydraulic unit HU is provided between the master cylinder MC and the wheel cylinder WC. The hydraulic unit HU is controlled by a braking signal Br from the controller ECB. For example, when anti-skid control is performed, the hydraulic pressure of the wheel cylinder WC is adjusted independently for each wheel by the hydraulic unit HU. The hydraulic unit HU includes a plurality of solenoid valves (for example, two-position valves), a low pressure reservoir, a hydraulic pump, and an electric motor.

<Calculation processing of drive torque increase control>
The calculation processing of the drive torque increase control will be described with reference to the functional block diagram of FIG. In the drive torque increase control, the braking torque Bq is applied to the drive wheel WD by the traveling resistance (for example, engine brake) by the drive source PW, and the drive wheel WD tends to lock (that is, generation of excessive deceleration slip). To suppress this, the drive torque Dq of the drive source PW is increased. The drive torque increase control includes two different controls respectively corresponding to non-braking and braking.

The drive torque increase control is performed by the vehicle speed calculation block VX, slip amount calculation block SL, vehicle acceleration calculation block GS, command torque calculation block DS, limit processing block LS, braking determination block FB, compensation value setting block DB, selection processing block SR And a drive torque control block DQ.

In the vehicle speed calculation block VX, the traveling speed (vehicle speed) Vx of the vehicle VH is calculated. The wheel speed Vw is detected by the wheel speed sensor VW of each wheel WH, and the vehicle speed Vx is calculated based on the wheel speed Vw. For example, when the vehicle VH is not braking (including acceleration), the vehicle speed Vx is determined based on the slowest one of the wheel speeds Vw. Further, at the time of braking of the vehicle VH, the vehicle speed Vx is determined based on the fastest one of the wheel speeds Vw.

In the slip amount calculation block SL, the reduction slip amount Sl is calculated based on the vehicle speed Vx and the wheel speed Vw. The deceleration slip amount Sl represents the degree of deceleration slip of the wheel WH and is a control variable (state amount) in the drive torque increase control. Here, the "deceleration slip" is a slip in the rotational direction of the wheel WH, and in the case where the deceleration slip is occurring, the state is "Vw <Vx". For example, the difference between the vehicle body speed Vx and the wheel speed Vw (a physical quantity is a speed, referred to as "deceleration slip speed") is calculated as a reduction slip amount Sl (= Vx-Vw). Further, the difference between the vehicle speed Vx and the wheel speed Vw (a dimensionless number, referred to as "deceleration slip ratio") with respect to the vehicle speed Vx may be determined as the deceleration slip amount Sl (= (Vx-Vw) / Vx) . That is, the reduction slip amount Sl is calculated based on at least one of the slip speed and the slip ratio. As the reduction slip amount Sl is larger, the difference between the vehicle speed Vx and the wheel speed Vw is larger, and as the slip amount Sl is smaller, the difference is smaller. In addition, the wheel slip reverse to a deceleration slip is "acceleration slip", and when this acceleration slip has generate | occur | produced, it is a state of "Vw> Vx."

In the vehicle body acceleration calculation block GS, the vehicle body acceleration Gs is calculated based on the vehicle body speed Vx. Specifically, the vehicle speed Vx is time-differentiated to calculate the vehicle acceleration Gs. In addition, the vehicle body acceleration Gs may be determined based on the detection result of the longitudinal acceleration sensor GX (longitudinal acceleration Gx). When the longitudinal acceleration Gx is adopted, the longitudinal acceleration Gx is determined as the vehicle body acceleration Gs as it is. In the vehicle body acceleration calculation block GS, the vehicle body acceleration Gs is calculated based on at least one of the vehicle body speed Vx and the longitudinal acceleration Gx. The vehicle body acceleration Gs is represented by a negative sign when the vehicle VH is in a decelerating state, and is represented by a positive sign when the vehicle VH is in an accelerating state.

In the command torque calculation block DS, the command torque Ds is calculated based on the reduction slip amount Sl and the calculation map Zds. The command torque Ds is a target value for commanding the drive source PW to increase the drive torque Dq. In accordance with the calculation map Zds, the command torque Ds is calculated to increase monotonously according to the increase of the slip amount Sl. Further, when the slip amount Sl is less than the predetermined slip sx, the command torque Ds is determined as a value smaller than "0" (that is, to request the braking torque), and the slip amount Sl is larger than the predetermined slip sx Is determined as a value larger than “0” (that is, to request a drive torque). Here, the predetermined slip sx is a constant set in advance.

In the limit processing block LS, a limited command torque (referred to as “limit command torque”) Dss is calculated based on the command torque Ds and the vehicle body acceleration Gs. The limit command torque Dss is obtained by limiting the command torque Ds from the command torque calculation block DS. In the limiting processing block LS, it is determined based on the vehicle body acceleration Gs whether the vehicle VH is in the decelerating state or in the accelerating state. Then, at the time point when the vehicle VH changes from the decelerating state to the accelerating state (corresponding operation cycle), the command torque Ds is held. Specifically, first, a value ds (referred to as “transition torque”) of the command torque Ds at the time when the vehicle acceleration Gs having a negative sign changes to “0” (referred to as “transition time”) is stored. Then, after the transition time point, when the command torque Ds becomes larger than the transition torque ds, the command torque Ds is limited to the transition torque ds, and the limited command torque Dss is calculated. The limit command torque Dss is output to the selection processing block SR.

In the braking determination block FB, “whether or not braking is in progress” is determined based on at least one of the braking operation amount Ba and the braking operation signal St. In the braking determination block FB, a determination flag Fb for displaying the result is determined as the determination result of the presence or absence of braking. For example, when the operation amount Ba is equal to or more than the predetermined value bo, “during braking” is affirmed, and “1 (with braking)” is output as the determination flag Fb. On the other hand, if “Ba <bo”, “during braking” is denied, and “0 (non-braking)” is output as the determination flag Fb. Here, the predetermined value bo is a preset constant corresponding to the play of the braking operation member BP. Further, when the operation signal St is on, "Fb = 1 (during braking)" is determined, and when the operation signal St is off, "Fb = 0 (non-restricting)" is determined. .

In the compensation value setting block DB, the compensation value db is output to the selection processing block SR. For example, the compensation value db is set as a preset predetermined value (constant) which is equal to or greater than “0 (zero)”. Further, the compensation value db may be set based on the transition torque ds (corresponding to “transition value”). Here, the compensation value db is a value that does not depend on the slip amount Sl. For example, the compensation value db is determined to be equal to the transition value ds. Alternatively, the compensation value db may be determined in consideration of a predetermined value corresponding to the road surface friction coefficient as the transition value ds.

In selection processing block SR, one of limit instruction torque Dss and compensation value db is selected based on determination flag Fb. When "Fb = 0" and not braking (ie, when the braking actuator BR is not operating), the limit instructing torque Dss is selected as the required torque Dr. On the other hand, “Fb = 1”, and at the time of braking (that is, when the braking actuator BR is operating), the compensation value db is adopted as the required torque Dr. The required torque Dr is an instruction value that requests the drive controller ECP to increase the drive torque Dq.

As described above, the arithmetic processing from the vehicle speed calculation block VX to the selection processing block SR is programmed in the braking controller ECB.

In the drive torque control block DQ in the drive controller ECP, the drive torque Dq is determined based on the acceleration operation amount Aa at the normal time (when the drive torque increase control is not performed). Then, the drive signal Pw is calculated so that the drive torque Dq is achieved, and the drive source PW is controlled based on the drive signal Pw. Specifically, the throttle opening degree Th and the fuel injection amount Fi are controlled based on the drive signal Pw.

On the other hand, when the drive torque increase control is executed, the required torque Dr is received by the drive controller ECP via the communication bus CM. In this case, in the drive torque control block DQ, the drive signal Pw is calculated based on the required torque Dr so that the drive torque Dq is increased. Then, based on the drive signal Pw, the drive source PW is controlled (increased adjustment). Since the drive torque Dq is increased by the required torque Dr, the traveling resistance by the drive source PW is reduced, and the deceleration slip of the drive wheel WD is reduced. As a result, the grip of the drive wheel WD is recovered.

Here, the restriction processing block LS may be omitted. In this case, the command torque Ds is input to the selection processing block SR instead of the limit command torque Dss. In the selection processing block SR, “Dr = Ds” is selected when the actuator BR is not operating (when “Fb = 0”). On the other hand, at the time of operation of the actuator BR (in the case of “Fb = 1”), “Dr = db” is selected.

In the drive torque increase control, the required torque Dr is determined based on the slip amount Sl at the time of non-braking, so that the deceleration slip due to the resistance of the drive source PW can be suitably suppressed. In addition, in the case where a deceleration slip is generated by the brake actuator BR (master cylinder MC or hydraulic unit HU), the compensation is not dependent on the slip amount Sl (that is, a value independent of the slip amount Sl) The value db is determined as the required torque Dr. Braking control such as anti-skid control and vehicle stabilization control is executed based on the slip amount Sl as in the drive torque increase control. By adopting the compensation value db, interference with the deceleration slip by the braking actuator BR can be suppressed, and it can be avoided that the drive torque increase control becomes oscillatory.

<Restriction processing block LS>
The restriction processing block LS will be described with reference to the time-series diagram of FIG. When traveling at a constant speed on a road surface with a low coefficient of friction, it is assumed that the acceleration operation member (for example, an accelerator pedal) AP is suddenly returned to “Aa = 0”. In the command torque calculation block DS, the command torque Ds is calculated based on the slip amount Sl, and the command torque Ds is limited by the limit processing block LS. However, the command torque Ds after the limit is expressed as "limit command torque Dss". Be done. The limit command torque Dss is a final request signal for the drive torque control block DQ.

At time t0, the acceleration operation member AP is returned, and the braking torque Bq by the traveling resistance (for example, the engine brake) by the drive source PW is suddenly increased. Thereby, the deceleration slip amount Sl of the drive wheel WD gradually increases from time t0. That is, the difference between the vehicle speed Vx and the wheel speed Vw starts to gradually increase.

At time t1, in the drive torque increase control, the slip amount Sl which is a control variable exceeds its start threshold value, so control execution is started and the command torque Ds increases to the value d1 according to the calculation map Zds. Be done. Since the drive torque Dq of the drive source PW is increased based on the command torque Ds, the decelerating motion of the drive wheel WD is alleviated, and the decelerating slip amount Sl is gradually decreased although it is increased once. At this time, since the braking torque Bq from the drive source PW acts on the vehicle VH, the vehicle VH is in a decelerating state, and the vehicle body acceleration Gs is a negative (minus) value.

At time t2, the slip amount Sl starts to decrease and the wheel speed Vw starts to approach the vehicle speed Vx. The command torque Ds is calculated larger as the slip amount Sl is larger based on the calculation map Zds, and is calculated smaller as the slip amount Sl is smaller. Therefore, from time t2, the command torque Ds is gradually decreased. Along with this, the drive torque Dq is decreased, and the vehicle body acceleration Gs is gradually increased. That is, the degree of deceleration of the vehicle VH gradually decreases.

At time t3, the vehicle body acceleration Gs changes from a negative sign to "0" or a positive sign. That is, at time t3, the vehicle VH changes from the decelerating state to the accelerating state. The command torque Ds at this time t3 (transition time) is stored as the transition torque ds. From time t1 to time t3, the command torque Ds is not substantially limited, and the command torque Ds from the command torque calculation block DS is determined as it is as the limit command torque Dss (that is, "Dss = Ds") . However, after time t3, the commanded torque Ds is limited by the transition torque ds. Since the transition torque ds is the drive torque Dq corresponding to “Gs = 0”, the transition torque ds is a value corresponding to the frictional resistance of the transmission TR or the like, and a value of “0” or more (not the braking torque , Driving torque).

For example, after time t3, the limit command torque Dss is held at the transition torque ds. By maintaining the state of “Dss = ds”, the traveling resistance caused by the drive source PW and the transmission TR is suitably compensated, and the slip state of the drive wheel WD can be appropriately suppressed. Furthermore, since the drive torque Dq generated by the drive source PW includes a time delay, the drive torque Dq becomes oscillatory due to the time delay by maintaining the instruction torque Dss constant. It can be avoided. Here, although “Dss = ds”, a value “ds ± α” in which a predetermined value α is added to the transition torque ds may be employed.

Further, the transition torque ds may be set to the upper limit value, and the command torque Ds may be limited so as not to exceed the transition torque ds. That is, when the command torque Ds is equal to or less than the transition torque ds, the command torque Ds is not limited and is determined as the final command torque Dss as it is. However, when the command torque Ds is larger than the transition torque ds, the command torque Ds is limited to the transition torque ds and is calculated by “Dss = ds”. Also in this case, the traveling resistance due to the drive source PW and the transmission TR can be suitably compensated, and the grip state of the drive wheel WD can be properly recovered. Similarly to the above, as the upper limit value of the command torque Ds, a value “ds ± α” in which the predetermined value α is considered in the transition torque ds may be employed.

As described above, the command torque Ds is limited based on the change of the vehicle body acceleration Gs. If the wheel speed Vw of the drive wheel WD is decreasing, it is desirable to generate a larger drive torque Dq in order to recover the wheel speed quickly. However, if drive torque Dq is excessive, vehicle VH is unnecessarily accelerated. Therefore, based on the change in the vehicle body acceleration Gs, the acceleration state of the vehicle VH is taken into consideration, and the command torque Ds is limited. Therefore, the above-mentioned trade-off is satisfied, and the deceleration slip of the drive wheel WD can be suitably suppressed.

Furthermore, the compensation value db can be determined based on the transition torque (transition value) ds. The transition value ds corresponds to a drive torque that can compensate for the loss of the power transmission function such as the transmission TR. Therefore, the compensation value db is set based on the transition value ds. Here, the compensation value db is set as a value (for example, a constant) which is not influenced by the slip amount Sl.

<Operation and effect>
The operation and effect will be described with reference to the schematic view of FIG. The drive torque control device CS according to the present invention includes a drive source PW, a wheel speed sensor VW, and a controller ECU. The drive torque PW is applied to the drive wheel WD by the drive source PW to accelerate the vehicle VH. The wheel speed sensor VW detects the speed (wheel speed) Vw of the wheel WH of the vehicle VH. Then, the controller ECU calculates the required torque Dr instructing an increase in the drive torque Dq to suppress the decelerating slip amount Sl of the drive wheel WD based on the wheel speed Vw, and the drive source PW is calculated based on the required torque Dr. Is controlled.

First, the relationship between the output of the drive source PW and the torque of the drive wheel WD will be described. The drive source PW transmits power (drive torque Dq) to the drive wheel WD via the transmission TR. The transmission TR includes a clutch CL, a reduction gear GN, and differential gears DZ, DC, DK. The command torque Dss is calculated as a target value of the output of the drive source PW. Therefore, the command torque Dss is a target value of the torque between the drive source PW and the transmission TR (the output torque of the drive source PW, which is the input torque of the transmission TR) shown by the arrow (A). Resistive force (for example, engine brake torque) by drive source PW is generated due to mechanical friction loss of drive source PW, accessory drive loss, fluid resistance of intake and exhaust (when drive source PW is an internal combustion engine), etc. . Furthermore, the braking torque Bq is generated at the wheel not only by the drive source PW but also by the resistance (friction loss etc.) by the power transmission mechanism such as the transmission TR and the drive shafts SZ, SC, SK.

In the drive wheel WD, when the wheel slip (deceleration in the rotational direction of the wheel and acceleration slip) is "0 (not generated)", the drive torque Dq and the braking torque Bq balance at the axle JW, and the axle JW This is the case when the torque around it is "0". Therefore, in consideration of the power loss in the power transmission mechanism, the drive torque Dq by the drive source PW is adjusted so that the torque of the portion (input torque to the drive wheel WD) shown by the arrow (B) becomes "0". It needs to be done.

The acceleration Gs of the vehicle VH is calculated, and the command torque Ds at the time (transition time) when the vehicle body acceleration Gs changes from the deceleration state to the acceleration state is stored as the transition value ds. Then, the command torque Ds is limited based on the transition value ds, and the command torque Dss is determined. At the transition point of the vehicle body acceleration Gs, “Gs = 0”, and neither the driving torque Dq nor the braking torque Bq acts on the driving wheel WD. That is, the transition value ds corresponds to a drive torque that can compensate for the loss of the power transmission function of the transmission TR or the like. Therefore, the command torque Ds at the transition time is stored as the transition value ds, and the limiting process of the command torque Ds is performed based on the transition value ds.

For example, after the transition time point, the command torque Dss is limited to coincide with the transition value ds. Further, the upper limit value of the command torque Ds is determined by the transition value ds, and the command torque Ds is limited so as not to exceed the transition value ds, and the command torque Dss is determined. Since commanded torque Dss is limited by transition value ds, power loss of the power transmission mechanism is suitably compensated, and appropriate drive torque increase control can be executed.

In the drive torque control device CS according to the present invention, it is determined whether the braking actuator BR is in operation or not (that is, whether it is in braking or not). Then, when the actuator BR is inoperative (ie, not braking), drive torque increase control is executed based on Ds (or limit command torque Dss) calculated based on the slip amount Sl. Therefore, excessive deceleration slip due to the drive source PW can be reliably suppressed. Further, when the command value Dss to which the limitation is added is adopted as the required torque Dr, the vehicle VH is prevented from being accelerated more than the driver's intention when the output torque of the drive source PW is increased. Disturbance to the driver can be suppressed.

On the other hand, when the braking actuator BR (master cylinder MC, generic term for the hydraulic unit HU) is in operation (that is, at the time of braking), drive torque increase control is executed based on the compensation value db which does not depend on the slip amount Sl. Be done. The generation of the driving torque Dq by the driving source PW is relatively slow, and the generation of the braking torque Bq by the braking actuator BR is relatively fast. For example, braking control such as antiskid control and vehicle stabilization control is also performed based on the slip amount Sl. Therefore, when the drive torque increase control is executed based on the slip amount Sl, control interference may occur. However, while the brake actuator BR is in operation (including the time of execution of the braking control), the drive torque increase control is performed based on the compensation value db (for example, a predetermined value of “0” or more) which is not affected by the slip amount Sl. To be executed. Therefore, interference between the drive torque increase control and the braking control can be reliably avoided. The compensation value db may be set based on the transition value ds.

Other Embodiments
Hereinafter, other embodiments will be described. Also in the other embodiments, the same effects (suppression of excessive wheel slip at the time of braking, avoidance of control interference) are exerted.

In the above-described embodiment, the four-wheel drive type vehicle is exemplified as the vehicle VH on which the drive torque control device CS is mounted. Instead of this, a two-wheel drive vehicle may be employed. For example, in a front wheel drive vehicle, the front wheels are drive wheels WD and the rear wheels are non-drive wheels. In a rear wheel drive vehicle, the front wheels are non-drive wheels and the rear wheels are drive wheels WD.

The drive torque control device CS functions not only in the case of braking (manual brake) by the driver's operation of the braking operation member BP, but also at the time of operation of the automatic brake. In the automatic brake, a braking force is generated by the hydraulic pressure unit HU. Therefore, in the braking determination block FB, it is determined whether or not the braking actuator BR is in operation. As in the manual braking, in the braking determination block FB, "Fb = 1 (during braking)" is output when the automatic braking is operating, and "Fb = 0 (non-braking)" is output when the automatic braking is not operating.

In the above embodiment, the configuration of the disk brake device (disk brake) has been exemplified. In this case, the friction member MS is a brake pad, and the rotating member KT is a brake disk. Instead of the disc brake, a drum brake may be employed. In the case of a drum brake, a brake drum is employed instead of the caliper CP. The friction member MS is a brake shoe, and the rotating member KT is a brake drum.

In the said embodiment, the thing of the hydraulic type via damping | braking liquid was illustrated as an apparatus which provides a damping | braking torque to the wheel WH. Alternatively, an electric motor driven by an electric motor may be employed. In the electrically driven device, the rotational power of the electric motor is converted into linear power, whereby the friction member MS is pressed against the rotation member KT. Therefore, the braking torque is directly generated by the electric motor regardless of the pressure of the braking fluid. Furthermore, a composite type configuration may be formed in which a hydraulic type through a braking fluid is adopted as the front wheel, and an electric type is adopted as the rear wheel.

In the above embodiment, the request torque Dr is calculated by the braking controller ECB, the request torque Dr is transmitted to the drive controller ECP, and the drive torque Dq is controlled by the drive controller ECP. The various controllers (ECB etc.) can mutually exchange signals by the communication bus CM. Therefore, various operations can be processed by any controller.

Claims

A drive source for applying a drive torque for accelerating the vehicle to the drive wheels;
An actuator for applying a braking torque to the wheels to decelerate the vehicle;
A wheel speed sensor for detecting the speed of the wheel of the vehicle;
A drive torque control device for a vehicle, comprising: a controller that calculates a required torque that requires an increase in the drive torque so as to suppress a reduction in slip of the drive wheel, and controls the drive source based on the required torque; In
The controller
If the actuator is not operating,
Based on the speed, the slip amount of the drive wheel is calculated, and the required torque is calculated based on the slip amount.
If the actuator is operating,
A driving torque control device for a vehicle, wherein the required torque is set to a compensation value that does not depend on the slip amount.
In the vehicle braking / driving control device according to claim 1,
The driving torque control device for a vehicle, wherein the compensation value is a preset constant equal to or more than zero.
In the vehicle braking / driving control device according to claim 1,
The controller
If the actuator is not operating,
Storing the required torque as a transition value when the acceleration of the vehicle transitions from a decelerating state to an accelerating state;
A drive torque control device for a vehicle configured to set the compensation value based on the transition value.