JP2001030794A - Cruise control system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deviation in the estimated value when a vehicle retracted at start on a slope or at other occasions by providing a braking/driving control means having a calculation means for calculating a running resistance estimated value, while stopping calculation when the vehicle stops and restarting calculation when the vehicle runs under the predetermined condition. SOLUTION: In a running resistance estimation section, the drive shaft torque conversion value TDH is calculated, permitting speed control which is not affected by disturbance (S7). Deceleration starts from this state, and when a vehicle speed VS is reduced at a predetermined value VK or less to actuate an anti-lock braking system, or when the vehicle stops, the calculation of the conversion value TDH is stopped (S8). Later, when the ABS returns to an unactuated state while the vehicle speed VS is almost one at which the vehicle stops, the calculation of the conversion value TDH is restarted. When the vehicle starts from the stop state, the condition in which calculation is stopped because the vehicle speed VS has not reached a predetermined value VK (S8). After that, when the vehicle speed VS exceeds the predetermined value VK and the ABS is not actuated, the calculation of the conversion value TDH is restarted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device for a vehicle for controlling the vehicle speed so that the speed of the vehicle coincides with a target vehicle speed.

[0002]

2. Description of the Related Art As conventional vehicle travel control devices, for example, Japanese Patent Application Laid-Open No. Hei 9-11776 (hereinafter, referred to as a first conventional example) and Japanese Patent Application Laid-Open No. 9-242882 (hereinafter, referred to as a second conventional example). ) And Japanese Patent Application Laid-Open No. 9-107735 (hereinafter, referred to as a third conventional example) are known.

In the first prior art, a running resistance estimated value is calculated based on a difference between a target braking / driving force (torque) calculated based on a target vehicle speed and a differential value of an actual vehicle speed. A constant speed traveling control device for a vehicle is disclosed in which the vehicle speed is controlled at the target vehicle speed even on a sloped road surface by performing the braking / driving force control by feeding back to the target braking / driving force.

The second prior art and the third prior art include running (gradient) based on vehicle acceleration calculated from vehicle speed, driving force of an engine, braking force calculated from brake fluid pressure, rolling resistance, air resistance, and gear ratio. ) A method for calculating the resistance is disclosed.

[0005]

However, in the above-described first to third conventional examples, the vehicle speed is detected in the forward direction regardless of the forward / reverse movement of the vehicle, so that when stopping or starting on an uphill, When the vehicle retreats, the vehicle acceleration calculated from the vehicle speed reverses the sign of the actual vehicle acceleration. As a result, there is an unsolved problem that when the running resistance is calculated using the vehicle acceleration calculated from the vehicle speed, an accurate running resistance estimated value cannot be obtained.

In a vehicle equipped with an anti-lock brake control device, the braking pressure is controlled in accordance with the wheel slip ratio so that the wheels are not locked, so that the deceleration corresponding to the target braking / driving force (torque) is reduced. Since it cannot be generated, it is not possible to accurately estimate the running resistance value, and since the movement of the vehicle body and the movement of the wheels are different, the vehicle acceleration calculated from the vehicle speed is different from the actual vehicle acceleration, and as a result, There is an unsolved problem that the calculated running resistance value also has a large error.

Further, in a vehicle equipped with a traction control device, the braking force is controlled so as to prevent wheel slip during sudden acceleration, so that an acceleration corresponding to the target braking / driving force (torque) cannot be generated. Therefore, there is an unsolved problem similar to that of a vehicle equipped with the antilock brake control device. Furthermore, when the control range of the automatic transmission is changed, the driving force of the engine and its direction are changed in the D range, R range, N range, and the like, and the running resistance is estimated and calculated by the same calculation method. However, there is an unsolved problem that the value becomes different from the actual running resistance.

For these reasons, the vehicle speed control system that feeds back the running resistance value cannot solve the problem that the vehicle speed cannot be controlled according to the target vehicle speed when the vehicle speed control is performed to match the vehicle speed with the target vehicle speed. Issues. Therefore, the present invention has been made by focusing on the unsolved problem of the above-described conventional example, and a vehicle travel control device capable of performing vehicle speed control at a target vehicle speed while suppressing an error in a travel resistance estimated value. It is intended to provide.

[0009]

According to a first aspect of the present invention, there is provided a vehicle traveling control device comprising: a vehicle speed detecting means for detecting a vehicle speed of a host vehicle; and a vehicle speed detecting means for detecting a vehicle speed detected by the vehicle speed detecting means. A driving / driving force control means for controlling either the driving force or the braking force so as to match the target vehicle speed, wherein the braking / driving force control means controls the control amount of the braking / driving force and the vehicle speed. Running resistance estimation value calculation means for calculating a running resistance estimation value based on the vehicle speed detected by the detection means, wherein the running resistance estimation value calculation means interrupts the calculation of the running resistance estimation value when the vehicle stops. In addition, the present invention is characterized in that the calculation of the running resistance estimated value is restarted when the predetermined running state is attained.

In the invention according to the first aspect, the acceleration / deceleration control is performed by generating the braking / driving force in consideration of the running resistance estimated value by the braking / driving force control means so that the own vehicle speed matches the target vehicle speed. At this time, while the own vehicle is running, the running resistance estimation value is calculated, but when the vehicle stops, the calculation of the running resistance estimation value is interrupted, and this interrupted state is resumed and continued until the predetermined running state is reached. By doing so, it is possible to suppress the occurrence of an error in the running resistance estimation value when the vehicle retreats when starting up on an uphill.

According to a second aspect of the present invention, in the vehicle traveling control device according to the first aspect, the predetermined traveling state is such that when the vehicle speed is equal to or more than a predetermined value and when the traveling time is equal to or more than a predetermined value. It is characterized by being one of the above. In the invention according to the second aspect, when the own vehicle starts running and the own vehicle speed becomes equal to or higher than a predetermined vehicle speed or the running time after the start of running becomes equal to or longer than a predetermined time, the vehicle travels uphill. It is possible to suppress the occurrence of an error in the running resistance estimated value when the vehicle retreats at the start of the vehicle.

Further, a vehicle running control device according to a third aspect of the present invention includes a vehicle speed detecting means for detecting a vehicle speed of the own vehicle speed, and a driving force and a braking force for making the vehicle speed detected by the vehicle speed detecting means coincide with a target vehicle speed. And a braking / driving force control means for controlling any one of: a traveling state control state for detecting an operation state of the traveling state control means for suppressing and controlling the braking / driving force according to a traveling state of the vehicle. Comprising detection means,
The braking / driving force control unit includes a traveling resistance estimated value computing unit that computes a traveling resistance estimated value based on the control amount of the braking / driving force and the vehicle speed detected by the vehicle speed detecting unit. Suspends the calculation of the running resistance estimated value when the running state control means detects the operating state of the running state control means, and disables the running resistance estimated value when the running state control means becomes inactive. Is restarted.

According to the third aspect of the invention, the driving condition control means for controlling the wheel speed in accordance with the driving condition of the vehicle is activated, and the braking / driving force controlled by the braking / driving force control means and the actual driving force When the generated braking / driving force is different, the calculation of the running resistance estimated value is interrupted to prevent an error from occurring in the running resistance estimated value, and the running state control means is switched to the inactive state. When this happens, the calculation of the running resistance estimated value is restarted.

According to a fourth aspect of the present invention, in the vehicle traveling control apparatus according to the third aspect, the traveling resistance estimated value calculating means is configured to determine whether the operating time of the traveling state control means is less than a predetermined value. Is characterized in that it is configured to hold a running resistance estimated value immediately before the running state control means starts to operate, and to clear the running resistance estimated value when the running resistance control value exceeds the predetermined value.

In the invention according to the fourth aspect, when the operation time of the driving condition control means is equal to or less than a predetermined value, the road surface gradient does not change much, and the driving immediately before the driving condition control means starts operating. Although the estimated resistance value is retained, when the estimated resistance value exceeds a predetermined value, the estimated traveling resistance value is cleared assuming that the traveling resistance has changed. Still further, according to a fifth aspect of the present invention, in the vehicle traveling control device according to the third or fourth aspect, the traveling state control means is any one of an antilock brake control means and a traction control means. I have.

According to the fifth aspect of the present invention, the anti-lock brake control device is activated when the vehicle is decelerating on a low friction coefficient road surface or in a sudden braking state on a high friction coefficient road surface, and the wheel slip ratio is reduced. The wheel speed is controlled so as to maintain the target slip ratio, or the vehicle is rapidly accelerated on a road surface with a high friction coefficient, or accelerated on a road surface with a low friction coefficient, and the traction control device is activated. When the wheel speed for suppressing wheel slip is controlled, the calculation of the running resistance estimation value is interrupted, and when the anti-lock brake control device or the traction control device returns to the inactive state, the running resistance estimation value is calculated. Restart the operation.

According to a sixth aspect of the present invention, there is provided a vehicle travel control device according to any one of the first to fifth aspects, wherein the travel resistance estimated value calculating means is configured to determine the travel resistance according to a shift range of the automatic transmission. It is characterized in that it is configured to change the calculation method. In the invention according to the sixth aspect, it is possible to calculate the running resistance according to the shift range of the automatic transmission, and it is possible to suppress an error caused by changing the range of the automatic transmission.

[0018]

According to the first aspect of the invention, while the vehicle is traveling, the running resistance estimation value is calculated, but when the vehicle stops, the calculation of the running resistance estimation value is interrupted. By continuing the state from the restart of traveling to the predetermined traveling state, it is possible to accurately suppress the occurrence of an error in the traveling resistance estimated value when the vehicle retreats when starting on an uphill, and to accurately follow the traveling state. The effect that control can be performed is obtained.

Further, according to the vehicle travel control device of the second aspect, the own vehicle starts running and the own vehicle speed becomes equal to or higher than a predetermined vehicle speed, or the running time after the start of running is a predetermined time. With the above, it is possible to reliably prevent the occurrence of an error in the running resistance estimated value when the vehicle retreats at the time of starting on an uphill, and to obtain an effect that accurate following control can be performed. .

According to a third aspect of the present invention, there is provided a vehicle travel control device for calculating a travel resistance estimated value while a travel condition control means for controlling a wheel speed in accordance with a travel condition of a vehicle is in an operating state. , The error in the running resistance estimated value caused by the difference between the braking / driving force controlled by the braking / driving force control means and the actually generated braking / driving force can be reliably prevented, and accurate following can be performed. The effect that control can be performed is obtained.

According to a fourth aspect of the present invention, when the operating time of the driving condition control means is equal to or less than a predetermined value, the driving resistance estimated value immediately before the driving condition control means starts operating. However, the running resistance estimated value is cleared when the running resistance control value has exceeded a predetermined value. The following control can be performed without using the estimated value, and the effect that the error of the running resistance estimated value can be suppressed from expanding can be obtained.

Further, according to the vehicle traveling control device according to the fifth aspect, one of the antilock brake control device and the traction control device is activated, and the target braking / driving force by the following control and the actual braking / driving force are controlled. When the difference between the driving force and the driving force occurs, the calculation of the running resistance estimated value is interrupted, so that an effect of suppressing the error of the running resistance estimated value and performing the accurate following control can be obtained.

Further, according to the vehicle traveling control device of the present invention, it is possible to calculate the traveling resistance according to the shift range of the automatic transmission, and to suppress an error due to the range change of the automatic transmission. Is obtained.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment in which the present invention is applied to a rear-wheel drive vehicle provided with a preceding vehicle following control device that travels following a preceding vehicle. Are front wheels as driven wheels, 1RL, 1
RR is a rear wheel as a driving wheel, and rear wheels 1RL, 1R
R is driven to rotate by the driving force of the engine 2 being transmitted via the automatic transmission 3, the propeller shaft 4, the final reduction gear 5, and the axle 6.

Front wheels 1FL, 1FR and rear wheels 1RL, 1R
R is provided with a brake actuator 7 which is composed of, for example, a disk brake, which generates a braking force, and the brake hydraulic pressure of these brake actuators 7 is controlled by a brake control device 8. Here, the brake control unit 8 is adapted to generate a braking oil pressure in response to depression of a brake pedal, not shown, so as to generate a braking hydraulic pressure in accordance with a braking pressure command value P _BC from following controller 20 described below Wheel 1F when braking.
An anti-lock brake control device 9 is provided for controlling the braking pressure on the brake actuator 7 so that L to 1RR is not locked.

This anti-lock brake control device 9
Wheel sensor 1 for detecting wheel speed of each of wheels 1FL to 1RR
An estimated vehicle speed calculating section 9a as vehicle speed detecting means for constantly calculating an estimated vehicle speed by performing a predetermined calculation based on the wheel speeds V _{WFL to} V _WRR detected at 0FL to 10RR; Estimated vehicle speed and each wheel speed V
_A wheel slip rate is calculated based on _{WFL to} V _WRR, and a master cylinder pressure is increased to match the wheel slip rate to a target slip rate based on the wheel acceleration / deceleration obtained by differentiating the wheel slip rate and the wheel speed. A braking pressure control unit 9b for preventing wheel lock by forming a braking pressure on the brake actuator 7 of each wheel by performing pressure reduction and holding control. Then, the estimated vehicle speed from the estimated vehicle speed calculating unit 9a is outputted as a host vehicle speed V _S, the logic value when the brake pressure control section 9b is in anti-lock brake control "1", when it is uncontrolled in And outputs a control state signal AB having a logical value “0”.

The output of the engine 2 is controlled.
An engine output control device 11 is provided. This d
The engine output control device 11 includes an accelerator pedal (not shown).
The stepping amount of the controller and the following control controller 20
Throttle opening command value θ _RInstalled in engine 2 according to
Throttle actuator to adjust the throttle opening
To control the eta 12 and to further accelerate
Wheel slip when traveling on roads with low friction coefficient
Traction to control at least the throttle opening
A control device 13 is provided.

The traction control device 13 includes the own vehicle speed V _S and the wheel speed sensors 1 output from the estimated vehicle speed calculation section 9a of the antilock brake control device 9 described above.
A wheel slip ratio is calculated based on the wheel speeds V _{WFL to} V _WRR of 0FL to 10RR, and the throttle opening is controlled so as to match the target slip ratio to prevent wheel slip during acceleration, It outputs a control state signal TR having a logical value "1" during traction control and a logical value "0" during non-control.

On the other hand, a radar system which scans a laser beam as inter-vehicle distance detecting means for detecting an inter-vehicle distance between the vehicle and a preceding vehicle and receives reflected light from the preceding vehicle is provided below the vehicle body in front of the vehicle. An inter-vehicle distance sensor 14 having a configuration is provided. The detection signal output from the following distance sensor 14, the own vehicle speed Vs and the control state signal AB output from the antilock brake control device 9, and the control state signal TR output from the traction control device 13 follow-up control. The following controller 20 controls the inter-vehicle distance to the target inter-vehicle distance when the preceding vehicle is being captured, and sets the own vehicle speed V _S when the preceding vehicle is not being captured. There outputs the braking pressure command value P _BC and the throttle opening command value theta _R is controlled to set vehicle speed V _sET set in the brake controller 8 and engine output controller 11.

The follow-up control controller 20 includes a microcomputer and peripheral devices, and forms a control block shown in FIG. 2 in the form of software of the microcomputer. This control block measures the time from when the inter-vehicle distance sensor 14 sweeps the laser beam to when the reflected light of the preceding vehicle is received, and calculates the inter-vehicle distance L from the preceding vehicle.
Ranging signal processing unit 21 for calculating
And the own vehicle speed V _S read from the estimated vehicle speed calculating section 9 of the antilock brake control device 9.
And a target vehicle speed V ^* calculated by the inter-vehicle distance control unit 40, which calculates a target vehicle speed V ^* for maintaining the inter-vehicle distance L at the target inter-vehicle distance L ^* based on A vehicle speed control unit 50 for calculating a target drive shaft torque T ^* , and a throttle opening command value θ _R and braking for the throttle actuator 12 and the brake actuator 7 based on the target drive shaft torque T ^* calculated by the vehicle speed control unit 50. A drive wheel axle torque control unit 60 that calculates a pressure command value P _BC and outputs the calculated pressure command value to the throttle actuator 12 and the brake actuator 7 is provided.

The inter-vehicle distance control unit 40 calculates a target inter-vehicle distance L ^* between the preceding vehicle and the own vehicle based on the own vehicle speed V _S inputted from the estimated vehicle speed / speed calculation unit 9a. When a target inter-vehicle distance L ^* calculated by the target inter-vehicle distance setting section 42, and the inter-vehicle distance L inputted from the distance measurement signal processing section 21, the target inter-vehicle distance headway distance L based on the host vehicle speed V _S An inter-vehicle distance control calculation unit 43 that calculates a target vehicle speed V ^* to match L ^* is provided.

Here, the target inter-vehicle distance setting unit 42 determines the following from the own vehicle speed V _S and the time T ₀ (inter-vehicle time) until the own vehicle reaches a position L ₀ [m] behind the current preceding vehicle. (1)
The target inter-vehicle distance L ^* between the preceding vehicle and the own vehicle is calculated according to the equation. L ^* = by incorporating the concept of _{V S × T 0 + L S} ............ (1) This inter-vehicle time, as the vehicle speed becomes faster, are set so that the inter-vehicle distance becomes larger. L _S is the inter-vehicle distance when stopped.

The inter-vehicle distance control calculation unit 43 calculates a target vehicle speed for following the vehicle while maintaining the inter-vehicle distance L at the target value L ^* based on the inter-vehicle distance L, the target inter-vehicle distance L ^*, and the own vehicle speed V _S. Calculate V ^* . That is, assuming that the response of the own vehicle speed V _S to the target vehicle speed V ^* can be approximated by a first-order delay system with a time constant τ _V (1 / ω), the inter-vehicle distance control system will now be described with reference to FIG. The configuration shown in Fig. 3
At this time, the transfer characteristic from the target inter-vehicle distance L ^* to the actual inter-vehicle distance L can be expressed by the following equation (2).

[0034]

(Equation 1)

[0035] However, s is a Laplace operator, V _T is the preceding vehicle speed, K _V is a relative speed gain, K _L is the inter-vehicle distance gain. The (2) by setting the relative speed gain K _V and the inter-vehicle distance gain K _L to an appropriate value from the equation, it is possible to change the pole, the follow-up responsiveness can be a desired characteristic.

Specifically, as shown in the block diagram of FIG. 3, the deviation (L ^* −) between the target inter-vehicle distance L ^* and the actual inter-vehicle distance L is determined ^.
The value obtained by multiplying the distance control gain K _L to L), 'subtracted from the value obtained by multiplying the relative velocity gain K _V, this subtracted value and the differential value L' differential value of inter-vehicle distance L L representing the relative velocity between the own Vehicle speed V _S
To calculate the target vehicle speed V _L ^* as shown in the following equation (3).

V _L ^* = K _L (L ^* −L) + K _V · L ′ + L ′ + V _S (3) When the vehicle speed control unit 50 is in the follow-up control state, the vehicle speed control unit 50 When the vehicle is being captured, a smaller value between the target vehicle speed V _L ^* input from the following distance control unit 40 and the set vehicle speed V _SET set by the driver is set as the target vehicle speed V ^* , and the preceding vehicle is captured. a target vehicle speed setting unit 51 for setting a set vehicle speed V _sET as the target vehicle speed V ^* when no drive shaft torque for matching the vehicle speed V _S at the target vehicle speed V ^* set by the target vehicle speed setting section 51 Follow-up control drive shaft torque calculator 52 for calculating T _W
When the drive shaft torque calculating unit 52 when the normal control drive shaft torque calculating unit 53 for estimating a driving shaft torque T _DR from the throttle operating amount theta _M and the brake operation amount P _M by the driver's operation, is being followed Control in selecting the computed drive shaft torque T _W, the drive shaft torque selection for selecting the computed drive shaft torque T _DR in normal control drive shaft torque calculating unit 53 when tracking control is usually controlled in that it is released Part 54
A running resistance estimating unit 55 for calculating a driving torque converted value T _DH of the running resistance; and a driving torque converted value T of the running resistance calculated by the running resistance estimating unit 55 from the driving torque selected by the driving torque selecting unit 54. _DH is subtracted and target drive shaft torque T
_And a subtractor 56 for calculating _W ^* .

Here, the drive shaft torque calculating section 5 for follow-up control
2 is the target vehicle speed V as shown in the block diagram of FIG.^*
And own vehicle speed V_SDeviation (V^*-V_S) Is the speed control gain K
_SPAnd the drive shaft torque T_WIs configured to compute
Have been. In addition, the drive shaft torque calculation unit 53 for normal control
Is the throttle opening manipulated variable θ_MAnd engine speed N_EWhen
From the engine map with reference to the engine map shown in FIG.
K T _EIs calculated, and then the operation of the following equation (4) is performed to
Drive shaft torque T due to the twiddler's throttle operation_THCalculate
You.

[0039] _{T TH = R T R AT R} DEF {T E -J E (dN E / dt)} ............ (4) where, R _T is the torque amplifying ratio of the torque converter, R _AT automatic transmission gear ratio, R _{DE F} is differential gear ratio, J _E is engine inertia. Here, the automatic transmission gear ratio _RAT is set to a positive value when the shift range is the D range, a negative value when the shift range is the R range, and “0” when the shift range is the N range.

Further, the drive shaft torque T _BR due to the driver's brake operation can be obtained by calculating the following equation (5). T _BR = 8 A _B R _B μ _B P _M (5) where A _B is the brake cylinder area, R _B is the rotor effective radius, μ _B is the pad friction coefficient, and P _M is the master cylinder pressure.

Accordingly, the drive shaft torque estimated value T _DR by the driver's operation can be calculated by the following (6). T _DR = T _TH −T _BR (6) Further, the running resistance estimating unit 55 calculates the drive shaft torque conversion value T _DH of the running resistance by executing the running resistance estimation process shown in FIG. I do.

This running resistance estimating process is executed as a timer interrupt process at predetermined time intervals (for example, every 10 msec).
First, in step S1, it is determined whether or not the vehicle speed V _S exceeds a predetermined value V _K on a relatively low speed side. If V _S > V _K , the process shifts to step S2 to stop the vehicle. After the control flag FS indicating whether or not the vehicle is running is set to "0" indicating the vehicle running state, the process proceeds to step S3.

In step S3, it is determined whether or not the control state signal AB input from the antilock brake control device 9 has a logical value "1". When it is determined that the device 9 is in the non-operation state, the process proceeds to step S4, and after the count value t _AB for counting the operation elapsed time of the antilock brake control device 9 is cleared to "0", the process proceeds to step S4.
Go to 5.

In this step S5, it is determined whether or not the control state signal TR input from the traction control device 13 has a logical value "1". When it is determined that the traction control device 13 is in the operation state, the process proceeds to step S6, and the count value t for counting the operation elapsed time of the traction control device 13
_{After TR} is cleared to "0", the process proceeds to step S7.

In this step S7, the following equation (7) is calculated based on the target drive shaft torque T _W ^* calculated by the subtractor 56 and the own vehicle speed V _S to convert the drive resistance into the drive shaft torque. The value T _DH is calculated, updated and stored in a predetermined storage area, and then the process proceeds to step S8 to output the drive shaft torque conversion value T _DH stored in the storage area to the subtractor 56, and then the timer interrupt is performed. The process ends.

[0046] _{T DH = H (s) (} R W M V sV S -T W *) ............ (7) However, H (s) is filter, R _W is the tire radius, M _V is the vehicle weight, s is a Laplace operator. On the other hand, the step S
If the determination result of 1 is V _S ≦ V _K , it is determined that the vehicle is running at a low speed, and the process proceeds to step S9, where the vehicle speed V
It is determined whether or not _S is "0". If V _S = 0, it is determined that the vehicle is in the stop state, and the flow shifts to step S10 to set the control flag FS to "1" indicating the stop state. Then, the process proceeds to step S8. If V _S > 0, it is determined that the vehicle is traveling at a low speed, and the process proceeds to step S11 to determine whether or not the control flag FS is set to “1”. When it is reset to "0", the process proceeds to step S3, and when it is set to "1", the process proceeds to step S8.

If the result of the determination in step S3 is that the control state signal AB is a logical value "1", it is determined that the anti-lock brake control device 9 is in operation, and the flow proceeds to step S12 to execute the anti-lock brake control. The current count value t _AB representing the elapsed time since the start of operation of the device 9
A value obtained by adding "1" goes from a new count value t _AB in step S13, the count value t _AB is determined whether or not a set value or more t _S corresponding to the predetermined elapsed time, t _AB If ≧ t _S , the process proceeds to step S14 to clear the drive shaft torque conversion value T _DH of the current running resistance stored in the storage area to “0”, and then proceeds to step S8, where t _AB If <t _S , the process directly proceeds to step S8.

Further, when the result of the determination in step S5 is that the control state signal TR is a logical value "1", it is determined that the traction control device 13 is in operation and step S1 is performed.
5 and a new count value t _TR is obtained by adding “1” to the current count value t _TR representing the elapsed time since the start of the operation of the traction control device 13. It is determined whether or not the value t _TR has become equal to or greater than a set value t _S corresponding to a predetermined elapsed time, and t _TR ≧ t
_{If S} , the process proceeds to step S14, where t _AB <
If it is t _S , the process directly proceeds to step S8.

The driving torque conversion value T _DH of the running resistance is converted to the driving shaft torque T _S selected by the driving shaft torque selecting section 54.
, It is possible to eliminate the influence of road surface gradient, air resistance, rolling resistance, and the like. This running resistance estimation, the disturbance to the tracking control system is to have been eliminated, the transfer characteristic from the target vehicle speed V ^* to host vehicle speed V _S is represented by the following equation (8).

V _S = (K _SP / M _V ) V ^* / (s + K _SP / M _V ) (8) From the equation (8), the vehicle speed control gain K _SP is set to an appropriate value. Thus, the response characteristics of the vehicle speed control system can be matched with desired characteristics. Further, the drive shaft torque control unit 60
Is the target drive shaft torque T _W calculated by the vehicle speed control unit 50.
^* Target throttle opening for realizing the theta ^* and calculates a target braking pressure P _B ^*. Specifically, the torque amplification factor of the torque converter is R _T , the automatic transmission gear ratio is R _AT , the differential gear ratio is R _DEF , the engine inertia is J _E , the engine speed is N _E , and the brake torque is T _BR . Then, the relationship between the drive shaft torque T _W and the engine torque T _E can be expressed by the following equation (9).

[0051] _{T W = R T R AT R} DEF {T E -J E (dN E / dt)} - T BR ...... (9) Accordingly, the target driving torque T ^*, the following (8)
Calculates a target engine torque command value T _E ^* in the formula, the target throttle opening degree θ to generate the engine torque T _E ^*
* Is calculated with reference to the engine map shown in FIG. ^{_{T E * = J E (dN}} E / dt) + T * / R T R AT R DEF ............ (10) where, if the target throttle opening theta ^* is not less than zero positive value, the brake actuator 7, the target drive shaft torque T ^* can be achieved only by the engine torque. On the other hand, if the target throttle opening θ ^* is a negative value equal to or less than zero, the throttle opening is set to zero, and the drive shaft torque is adjusted to the target value in consideration of the drive shaft torque output by the engine. Calculate the brake operation amount.

As described above, the target engine torque T
The distribution control law of _E ^* and the target brake torque T _BR ^* is as follows. (A) target throttle opening ^{_{θ *> T B * = 0}} ............ (11) when _{0 T W = R T R AT} R DEF {T E -J E (dN E / dt)} ......... (12) Therefore, the engine torque of the following equation may be generated with respect to the target drive shaft torque T _W ^* , and the brake operation amount becomes zero from the equation (9).

[0053] _{T E = J E (dN E} / dt) + T W * / R T R AT R DEF ............ (13) (B) the throttle opening when the target throttle opening theta ^* = 0 is zero If the engine torque at that time is T _EO , the above equation (9) becomes the following equation (14). _{T W = R T R AT R} DEF {T E0 -J E (dN E / dt)} - T BR ...... (14) Thus, to generate a braking torque follows the target drive shaft torque T _W ^* Just do it.

[0054] ^{_{T BR = -T W * + R}} T R AT R DEF in _{{T E0 -J E (dN E} / dt)} (15) where the brake cylinder area A _B, the rotor effective radius R _B, pad Assuming that the friction coefficient is μ _B , a target brake pressure P _B ^* that is a brake operation amount with respect to the target brake torque T _B ^* can be expressed by the following equation (16). _{^{P B * = T B * /}} 8A B R B μ B ............ (16) Accordingly, as shown in FIG. 5, the target drive shaft torque T _W
^* To the target engine torque calculation unit 61 to
The target engine torque T _E ^{* is} calculated according to equation (0) ^.
The target engine torque _TE ^* is supplied to the throttle opening calculating unit 62, and the relationship between the target engine torque _TE ^* and the target throttle opening θ ^* is determined using the engine speed shown in FIG. 8 as a parameter. calculates a target throttle opening theta ^* with reference to the engine map representing, by supplying the target throttle opening theta ^* to the limiter 63 limits the value of the throttle opening degree zero to a maximum value, which the throttle opening and outputs to the engine output control device 11 as a degree command value theta _R.

On the other hand, the engine brake torque correction section 64
And the engine speed N_EBased on the engine map shown in FIG.
Engine throttle when throttle opening is zero
Luc T_E0And then calculate the engine torque T_E0Also
Then, the operation of the second term on the right side of the equation (15) is performed, and
Jin brake torque T_EBIs calculated, and this is added to the subtractor 65.
By supplying the engine brake torque T_EBFrom
Target drive shaft torque T_W ^*Subtract the target brake torque
T_B ^*And supplies this to the braking force calculation unit 66.
By performing the calculation of the above equation (16), the target braking pressure P_B
^*And supplies this to the limiter 67 to reduce the braking pressure to zero.
Braking pressure that can be output from the brake actuator 7 from the
, And the braking pressure command value P_BCAs braking system
Output to the control device 8.

The vehicle speed control unit 50 and drive shaft torque control unit 60 constitute braking / driving force control means.
Next, the operation of the above embodiment will be described. Now, assuming that, for example, a set switch (not shown) is turned on and the following control is started, the drive calculated by the following control drive shaft torque calculating unit 52 by the driving torque selecting unit 54 of the vehicle speed control unit 50 is assumed. Assuming that the shaft torque T _W is selected and the preceding vehicle is captured by the following distance sensor 14, the target vehicle speed _VL ^* calculated by the following distance calculating unit 40 by the target vehicle speed setting unit 51 is selected and the following control is performed. Drive shaft torque calculator 5
2 is supplied.

Therefore, when the vehicle travels on a flat road in an urban area,
Maintain an appropriate target inter-vehicle distance while capturing the preceding vehicle
It is assumed that the vehicle is following. In this state, the leading vehicle
When the vehicle is traveling at a constant speed, it is detected by the following distance sensor 14.
Inter-vehicle distance L is the target inter-vehicle distance L ^*By maintaining
Target vehicle speed V calculated by inter-vehicle distance calculation unit 40^*Is own vehicle speed
V_SAnd the vehicle speed control unit 50 sets the target vehicle speed V^*When
Own vehicle speed V_SVehicle speed V according to the deviation from_SMaintain goals
Drive shaft torque T_W ^*Is calculated, and this is the drive shaft torque control.
Output to the control unit 60, the target engine calculation unit
Engine torque T at 61_ERIs calculated, and the
Positive (θ^*> 0) target slot
Torque opening θ^*Is calculated, and this is limited by the limiter 63.
And the throttle opening command value θ_RAs engine output control
By being output to the device 11, the throttle actuator
The throttle opening is controlled to an appropriate value by the
Distance between marked cars L^*Is maintained at the constant speed running state.

At this time, since the throttle opening command value θ _R is a positive value, the target braking pressure T _BR ^* becomes “0”,
The braking pressure command value P _BC also becomes “0”, which is output to the braking control device 8, and the brake actuator 7 is controlled to the non-braking state. In the constant-speed running state on this flat road, both the anti-lock brake control device 9 and the traction control device 13 are in the inactive state, and the own vehicle speed V _S becomes the predetermined value V
Since at least _K, when the process of FIG. 8 is executed by the running resistance estimating unit 55, and proceeds from step S1 to the step S2, the control flag FS is reset to "0", then the count value in step S4 After t _AB is cleared to "0" and the count value t _TR is cleared to "0" in step S6, the process proceeds to step S7, where the vehicle speed control unit 50
, The target drive shaft torque T _W calculated by the subtractor 56
^* And the deviation between the drive torque multiplied by the vehicle weight M _V on the differential value of the vehicle speed V _S becomes a value corresponding to the air resistance and rolling resistance, the running resistance calculated by the aforementioned equation (7) drive shaft The torque conversion value T _HD becomes a value corresponding to the air resistance and the rolling resistance, which is output to the subtractor 56, and the own vehicle speed V _S is added to the target vehicle speed V _L ^* calculated by the follow-up control drive shaft torque calculator 52. by being fed back to the drive shaft torque T _W for matching, it is possible to perform vehicle speed control that eliminates the disturbance while the vehicle is running.

In this state, when the preceding vehicle is decelerated by, for example, a braking operation due to a red light or the like, the following distance sensor 1
By inter-vehicle distance L becomes shorter to detect at 4, ^* the target vehicle speed V calculated by the inter-vehicle distance calculating section 40 becomes a host vehicle speed V _S is smaller than value, the target drive shaft torque T _W calculated by the vehicle speed control unit 50 ^* Is a negative value. Therefore, the target engine torque calculation unit 61 in the drive shaft torque calculation unit 60
In by computed by the target engine torque T _E ^* is also a negative value, although the target throttle opening theta ^* also negatively calculated with reference to the engine map of FIG. 8, the limiter 63
Limits the target throttle opening θ ^* to “0”,
The throttle opening is controlled to “0” by the throttle actuator 12.

On the other hand, when the target drive shaft torque T _W ^* becomes negative, the target drive shaft torque T _W ^*
In the calculated engine brake torque T _EB is added to the target brake torque T _B ^* is a positive value, decrease the target braking pressure P _B ^* is the preceding vehicle calculated by the braking force computing section 66 in accordance with this A value corresponding to the speed is output to the braking control device 8 as a braking pressure command value P _BC ,
The own vehicle is also decelerated.

During this deceleration control, the own vehicle speed V _S becomes equal to the predetermined value V
_If it becomes _K or less, the process proceeds from step S1 to step S9 in the process of FIG. 7, but since the vehicle is traveling, the process proceeds to step S11. Since the control flag FS has been reset to “0”, the process proceeds to step S3. Transition. At this time, the vehicle is running on a low friction coefficient road surface, the anti-lock brake control device 9 is activated, and when the control state signal AB becomes a logical value "1", the process proceeds from step S3 to step S12, and the counting is performed. The value t _AB is incremented, but since the anti-lock brake control device 9 has just been activated, the value is less than the predetermined value t _S , and the process proceeds to step S8, whereby step S7 is performed.
The running operation of the resistance of the drive shaft torque corresponding value T _DH is not performed in the running resistance of the drive shaft torque corresponding value T _DH stored in the storage area in the preceding process in step S8 is output to the subtracter 56. Therefore, the calculation of the drive shaft torque conversion value of the running resistance is interrupted.

Thereafter, the increment of the count value t _AB is continued, and before the count value t _AB reaches the predetermined value t _S , the own vehicle speed V _AB is increased.
Antilock brake control device 9 just before _S stops
Returns to the inactive state, the control state signal AB becomes the logical value "0".
From 3, the process proceeds to step S <b> 4. If the count value t _AB is cleared to “0” and the traction control device 13 maintains the non-operation state, the process proceeds to step S <b> 7,
The calculation of the drive shaft torque conversion value _TDH of the running resistance according to the equation (7) is restarted, and this is output to the subtractor 56.

Thereafter, when the vehicle stops, step S9
To step S10, the control state flag F
By directly moving to step S8 after S is set to "1", the calculation of the drive shaft torque converted value _TDH of the running resistance is interrupted. From this stop state, when the preceding vehicle starts with a green signal, the own vehicle also starts following the green signal. However, since the own vehicle speed V _{S at} this time is less than the predetermined value V _K , the process proceeds from step S9 to step S11. Since the control flag FS is still set to "1", the process directly proceeds to step S8 to maintain the state where the calculation of the drive shaft torque conversion value _TDH of the running resistance is interrupted. For this reason, even when the host vehicle starts moving backward on an uphill, this does not affect the calculation of the drive shaft torque conversion value _TDH of the running resistance.

Thereafter, when the vehicle advances and the own vehicle speed V _S exceeds a predetermined value V _K , the process proceeds from step S1 to step S2 in the processing of FIG.
After S is reset to "0", the process proceeds to step S3, and when the anti-lock brake control device 9 and the traction control device 13 are in the inactive state, the process proceeds to step S7.
The calculation of the drive shaft torque conversion value T _DH of the running resistance is restarted.

Thereafter, when the preceding vehicle further accelerates and the own vehicle accelerates following the preceding vehicle, for example, the vehicle is traveling on a road surface with a low friction coefficient or the driving force is too large, and the driving wheel 1R
When the traction control device 13 is activated due to the slippage of the L and 1RR, in the process of FIG.
When the process proceeds from step S5 to step S15, the count value t _TR is incremented and the calculation of the drive shaft torque conversion value T _DH of the running resistance is interrupted. At
The process proceeds from step S5 to step S6, in which the count value t _TR is cleared to “0”, and then proceeds to step S7, where the calculation of the drive shaft torque converted value _TDH of the running resistance is restarted.

When the time elapsed since the anti-lock brake control device 9 or the traction control device 13 was activated becomes long and the count value t _AB or t _TR exceeds a predetermined value t _S , the processing shown in FIG. In step S1
3 or shift from step S16 to step S14,
The drive shaft torque conversion value _TDH of the running resistance immediately before the start of operation stored in the predetermined storage area is cleared to “0”.

For this reason, the road surface gradient or the like changes while the calculation of the drive shaft torque conversion value T _DH of the running resistance is interrupted, so that the estimation error of the drive shaft torque conversion value T _DH of the running resistance increases. Can be suppressed. Further, when the vehicle travels on an uphill or downhill gradient road surface, an amount of gradient resistance is added in step S7. The drive shaft torque converted value T _{DH of the} resistance becomes smaller, and conversely, when the vehicle is traveling on a downhill, the drive shaft torque converted value T _{DH of} the running resistance becomes larger than on a flat road.

On the other hand, from the following control state, whether the driver depresses the brake pedal or the accelerator pedal or operates the cancel switch,
By selecting a range other than the range, the following control is released and the state shifts to the normal control state, the vehicle speed control unit 50
By normal control drive torque T _DR based on the calculated driver's throttle operation and the brake operation in the normal control drive torque calculating section 53 in the driving torque selecting section 54 of is selected, this and the host vehicle speed V _S Is calculated based on the equation (7), the drive shaft torque conversion value T _DH of the running resistance is calculated, and this is output to the subtractor 56, so that the influence of the running resistance in the normal running state is obtained. The removed vehicle speed control can be performed.

At this time, the normal control drive torque calculating section 5
At 3, the automatic transmission gear ratio _RAT is set to a value corresponding to the D range, N range, R range, etc. selected by the select lever. It is possible to accurately estimate the drive shaft torque conversion value T _DH of the running resistance. In the above embodiment, the case where the present invention is applied to the follow-up control device has been described.However, the present invention is not limited to this, and the present invention is applied to any vehicle speed control that matches the own vehicle speed with the target vehicle speed. What you get.

Further, in the above embodiment, the case has been described where the driving resistance estimating section 55 calculates the driving shaft torque converted value T _HD of the driving resistance by software processing. However, the present invention is not limited to this. The arithmetic processing may be performed by hardware in which electronic circuits such as a counter, an arithmetic unit, and the like are combined. Further, in the above embodiment, the case where the automatic transmission 3 is provided on the output side of the engine 2 has been described. However, the present invention is not limited to this, and a continuously variable transmission can be applied.

Further, in the above embodiment, the brake actuator 7 constituted by a disc brake is used.
Although the case where the braking force is generated by controlling the braking pressure is described, the invention is not limited to this.
When an electric motor is applied as an actuator of a braking device, the present invention can be applied to a case where an electric output corresponding to the electric motor is controlled and a regenerative braking force is generated by an electric motor like an electric vehicle.

Further, in the above embodiment, the case where the present invention is applied to a rear wheel drive vehicle has been described.
The present invention can also be applied to a front wheel drive vehicle, and the case where the engine 2 is applied as a rotary drive source has been described. However, the present invention is not limited to this, and an electric motor can be applied. The present invention can also be applied to a hybrid vehicle using an engine and an electric motor.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of a tracking control controller of FIG. 1;

FIG. 3 is a block diagram showing a specific example of an inter-vehicle distance control unit in FIG. 2;

FIG. 4 is a block diagram illustrating a specific example of a vehicle speed control unit in FIG. 2;

FIG. 5 is a block diagram showing a specific example of a drive shaft torque control controller of FIG. 2;

FIG. 6 is a characteristic diagram showing an example of an engine map for obtaining a throttle opening degree from an engine torque.

FIG. 7 is a flowchart illustrating an example of a running resistance estimation process of a running resistance estimation unit.

FIG. 8 is a characteristic diagram showing an example of an engine map for obtaining an engine torque from a throttle opening.

FIG. 9 is a characteristic diagram for obtaining engine torque from the engine speed when the throttle opening is zero.

[Explanation of symbols]

 Reference Signs List 2 engine 3 automatic transmission 7 brake actuator 8 braking control device 9 anti-lock brake control device 10FL-10RR wheel speed sensor 11 engine output control device 12 throttle actuator 13 traction control device 14 inter-vehicle distance sensor 20 tracking control controller 40 inter-vehicle distance control Unit 50 vehicle speed control unit 55 running resistance estimation unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 314 F02D 45/00 314G (72) Inventor Yosuke Kobayashi 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan F-term (Reference) in Automobile Co., Ltd. EB04 EC02 EC04 FA04 3G301 JA00 LA03 LB02 LC03 NA08 NA09 NC02 ND02 PA11Z PE01Z PF01Z PF03Z PG00Z

Claims (6)

[Claims] 1. A vehicle speed detecting means for detecting a vehicle speed of a host vehicle, and a braking / driving force control means for controlling either a driving force or a braking force so that the vehicle speed detected by the vehicle speed detecting means coincides with a target vehicle speed. The driving / braking force control unit includes a running resistance estimated value calculating unit that calculates a running resistance estimated value based on the control amount of the braking / driving force and the vehicle speed detected by the vehicle speed detecting unit. The running resistance estimated value calculation means is configured to suspend the calculation of the running resistance estimated value when the host vehicle stops, and to restart the calculation of the running resistance estimated value when the vehicle enters a predetermined running state. A traveling control device for a vehicle. 2. The vehicle traveling control according to claim 1, wherein the predetermined traveling state is one of a time when the vehicle speed is equal to or more than a predetermined value and a time when the traveling time is equal to or more than a predetermined value. apparatus. 3. A vehicle speed detecting means for detecting a vehicle speed of the own vehicle speed, and a braking / driving force control means for controlling any one of a driving force and a braking force so that the vehicle speed detected by the vehicle speed detecting means coincides with a target vehicle speed. A traveling condition control state detecting means for detecting an operating state of a traveling state control means for suppressing and controlling the braking / driving force according to a traveling state of the vehicle, wherein the braking / driving force control means comprises: A running resistance estimated value calculating means for calculating a running resistance estimated value based on the control amount of the braking / driving force and the own vehicle speed detected by the vehicle speed detecting means, wherein the running resistance estimated value calculating means comprises: The calculation of the running resistance estimated value is interrupted when the detecting means detects the operating state of the running state control means, and the calculation of the running resistance estimated value is restarted when the running state control means becomes inactive. Is composed A travel control device for a vehicle, comprising: 4. The running resistance estimated value calculating means holds the running resistance estimated value immediately before the running situation control means starts operating when the running time of the running situation control means is equal to or less than a predetermined value. 4. The vehicle travel control device according to claim 3, wherein the travel resistance estimated value is cleared when the travel resistance exceeds a predetermined value. 5. The vehicle travel control device according to claim 3, wherein the travel status control means is one of an antilock brake control means and a traction control means. 6. The running resistance estimation value calculation means is configured to change a running resistance calculation method according to a shift range of an automatic transmission. 4. The vehicle travel control device according to claim 1.