JP2003112537A - Vehicle speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle speed control device that allows rapid convergence to a desired car speed and a desired inter-vehicle distance, and can achieve the optimal deceleration running after determining initialization regardless of a running state such as road surface gradient and acceleration before initialization. SOLUTION: The vehicle speed control device has a car speed command initial value setting part 514. The setting part 514 comprises a calculating part 514-a of a car speed command initial value reference value for calculating a car speed command initial value reference value VCOM- INI- B (t) so as to provide an optimal deceleration timing when a vehicle is running on a flat road and an acceleration at a predetermined time before the initialization is an intermediate value. The setting part 514 also comprises a calculating part 514-b of a car speed command initial value correction value for setting a result of adding a correction value VCOM- INI- C1 (t) by road surface gradient to a correction value VCOM- INI- C2 (t) by the acceleration as a final initial value correction value VCOM- INI- C (t). The setting part 514 also comprises a calculating part 514-c of a final car speed command initial value for calculating a car speed command initial value VCOM- INI (t) by subtracting the final initial value correction value VCOM- INI- C (t) from the car speed command initial value reference value VCOM- INI- B (t).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a vehicle speed control device for controlling a vehicle to travel while maintaining a set vehicle speed.

[0002]

2. Description of the Related Art As a conventional vehicle speed control device, for example,
The actual vehicle speed when the driver presses the switch is set as the target vehicle speed, and the vehicle speed command value is calculated from time to time based on the deviation between the actual vehicle speed and the actual vehicle speed. There is a method in which a target vehicle speed for maintaining the above-described inter-vehicle distance is calculated, and a vehicle speed command value is calculated every moment from a deviation between the target vehicle speed and the actual vehicle speed to make the actual vehicle speed follow the target vehicle speed (for example, JP 2000- No. 135934).

[0003]

However, in the conventional vehicle speed control device, the time change rate limiter of the vehicle speed command value (due to the problem of the capacity of the actuator for driving the throttle opening, the transmission, the brake, etc.). By providing the inclination limit), the speed change amount (acceleration or deceleration) of the vehicle is limited, so that there are problems listed below.

(1) Generally, in the control system including the above vehicle speed control device, there is a control delay between the control command value (vehicle speed command value) and the actual value (actual vehicle speed). If the driver decelerates by operating the coast switch after accelerating by operating the accelerator switch or accelerating when returning to the target vehicle speed by operating the resume switch, the actual vehicle speed will lag behind the vehicle speed command value. Therefore, the actual vehicle speed may exceed the vehicle speed command value. When the actual vehicle speed tries to return to the vehicle speed command value from that state, the vehicle speed command value has the acceleration / deceleration limit as described above, and therefore the convergence time to the target vehicle speed becomes long.

(2) In the case of the inter-vehicle distance control in which the inter-vehicle distance to the preceding vehicle is maintained, the acceleration / deceleration is limited in the same manner as described above. Therefore, for example, the preceding vehicle once accelerates and then decelerates. In this case, the following vehicle also accelerates and then decelerates, but it takes time to return to the desired inter-vehicle distance due to the deceleration limiter, and the vehicle may be too close to the preceding vehicle.

Therefore, in order to solve the above-mentioned conventional problems, the applicant of the present invention discloses in Japanese Patent Application No. 2000-143500 that the vehicle speed command value shifts from acceleration to deceleration and is higher than the actual vehicle speed. , The vehicle speed command value is initialized to a value equal to or less than a predetermined value (fixed value) than the actual vehicle speed, and the part for calculating the driving torque command value is also initialized (the internal variable is set to zero). Was proposed first.

Thus, when shifting from acceleration to deceleration,
Since the deceleration operation (drive torque command value is output to the negative side) is promptly entered, problems such as delay in deceleration timing and insufficient initial deceleration are solved. As a result, for example, the target inter-vehicle distance while following the preceding vehicle Can be followed quickly.

However, in this prior art,
Since the vehicle speed command initial value is always given by a constant set value irrespective of the running condition such as road gradient or acceleration before deceleration (slow acceleration or rapid acceleration), the following problems remain.

(1) In the same traveling pattern as above,
Since only the drive torque command value similar to that on a flat road is output even on a downhill, the timing of deceleration is delayed as shown in FIG. 22, and as a result, the inter-vehicle distance from the preceding vehicle is reduced and the driver feels uncomfortable. May give. On the contrary,
Since only the drive torque command value similar to that on a flat road is output even on an uphill road, deceleration is too early as shown in FIG. 23, and as a result, the inter-vehicle distance from the preceding vehicle increases and the driver feels insufficient acceleration. May be given to

(2) In the same traveling pattern as above,
Even when the acceleration before the initialization (before the deceleration) is relatively rapid, only the drive torque command value similar to the intermediate acceleration is output. Therefore, as shown in FIG. 24, the deceleration timing is delayed, and as a result, There is a possibility that the distance between the vehicle and the preceding vehicle is reduced and the driver feels uncomfortable. Further, conversely, even when the acceleration before the initialization (before the deceleration) is the relatively slow acceleration, only the drive torque command value similar to the intermediate acceleration is output, and therefore, FIG.
As shown in, the deceleration is too early, and as a result, the inter-vehicle distance from the preceding vehicle increases, which may give the driver a feeling of insufficient acceleration.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to quickly converge to a target vehicle speed or a target inter-vehicle distance as well as road slope and pre-initialization acceleration. An object of the present invention is to provide a vehicle speed control device capable of achieving optimum deceleration traveling after initialization determination regardless of the traveling state.

[0012]

To achieve the above object, in the invention according to claim 1, a vehicle speed command value determining means for calculating a vehicle speed command value so as to eliminate the deviation between the target vehicle speed and the actual vehicle speed, Driving torque command value calculating means for calculating a driving torque command value based on the vehicle speed command value from the vehicle speed command value determining means, and a command to the vehicle speed control actuator based on the driving torque command value from the driving torque command value calculating means In a vehicle speed control device including actuator command value calculation means for calculating a value, the vehicle speed command value determination means includes a reference vehicle speed command value calculation unit for calculating a reference vehicle speed command value from a vehicle speed command value change amount, and a vehicle speed command. An initialization determination unit that determines whether to initialize the value and the drive torque command value, a road surface slope estimation unit that estimates a road surface slope, and a slope estimated value from the road surface slope estimation unit are input, Compared with the cross-road, when the estimated slope value indicates an uphill, the vehicle speed command initial value is set higher, and when the estimated slope value indicates a downhill, the vehicle speed command initial value is set lower. Either the reference vehicle speed command value from the reference vehicle speed command value calculation unit or the vehicle speed command initial value from the vehicle speed command initial value setting unit is selected by the value setting unit and the initialization determination signal from the initialization determination unit. And a final vehicle speed command value determining unit that determines a final vehicle speed command value.

Further, in the invention according to claim 3, an acceleration estimating unit for estimating the vehicle acceleration is provided, and the vehicle speed command initial value setting unit inputs the acceleration estimated value before a predetermined time before initialization from the acceleration estimating unit. The vehicle speed command initial value is set higher when the acceleration estimated value shows a small acceleration, and the vehicle speed command initial value is set lower when the acceleration estimated value shows a large acceleration.

[0014]

The operation and effect of the vehicle speed command value determining means in the invention according to claim 1 will be described. The reference vehicle speed command value calculation unit calculates the reference vehicle speed command value from the vehicle speed command value change amount. Then, the initialization determination unit determines whether or not to initialize the vehicle speed command value and the drive torque command value, the road surface slope estimation unit estimates the road surface slope, and the vehicle speed command initial value setting unit estimates the road surface slope. If the estimated slope value indicates an uphill, the vehicle speed command initial value is set to a higher value, and if the estimated slope value indicates a downhill, the vehicle speed command is input. The initial value is set to a low value, and in the final vehicle speed command value determination unit, the reference vehicle speed command value from the reference vehicle speed command value calculation unit or the vehicle speed command initial value setting unit is received from the initialization determination signal from the initialization determination unit. Speed finger The final vehicle speed command value by either a default value is selected is determined.

Therefore, in addition to the effects of the prior art, when the vehicle speed command initial value is selected as the final vehicle speed command value by the initialization determination signal, the deceleration timing on the uphill is too early or the acceleration is insufficient due to the initial excessive deceleration. It is possible to solve the problem that the driver feels uncomfortable as the vehicle-to-vehicle distance decreases due to the feeling of feeling, delay of deceleration timing on a downhill, and insufficient initial deceleration.

The setting operation of the vehicle speed command initial value in the vehicle speed command initial value setting unit of the invention according to claim 3 will be described. In the vehicle speed command initial value setting unit, the acceleration before a predetermined time from the acceleration estimating unit is initialized. If the estimated value is input and the acceleration estimated value shows a low acceleration, the vehicle speed command initial value is set higher, and if the acceleration estimated value shows a rapid acceleration, the vehicle speed command initial value is set lower. .

Therefore, in addition to the effects of the prior art, when the vehicle speed command initial value is selected as the final vehicle speed command value by the initialization determination signal, the deceleration timing before the initialization determination is too early or the deceleration timing is slow. It is possible to remedy the problem that the driver feels uncomfortable due to the decrease in the inter-vehicle distance due to the feeling of insufficient acceleration due to excessive deceleration, the delay in the deceleration timing due to the sudden acceleration before the initialization determination, and the initial insufficient deceleration.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment for realizing a vehicle speed control device according to the present invention will be described below based on a first embodiment corresponding to claims 1 to 6.

(First Embodiment) FIG. 1 is a block diagram showing the overall construction of a vehicle speed control device according to the first embodiment. In FIG. 1, 10 is a vehicle speed sensor, 20 is a set switch, 30 is a coast switch, and 40 is a coast switch. Is an accelerated switch, 5
0 is a brake actuator (vehicle speed control actuator), 60 is a throttle actuator (vehicle speed control actuator), 70 is a continuously variable transmission (vehicle speed control actuator), 80 is an engine rotation sensor, 90 is an accelerator pedal sensor, 100 is a steering angle sensor, Reference numeral 500 is a vehicle speed control unit, 510 is a vehicle speed command value determination unit (vehicle speed command value determination unit), 520 is a vehicle speed command maximum value setting unit, 530 is a drive torque command value calculation unit (drive torque command value calculation unit), 54
0 is a gear shift command value calculation unit (actuator command value calculation means), 550 is an actual gear ratio calculation unit, 560 is an engine torque command value calculation unit (actuator command value calculation unit), 5
Reference numeral 70 is a target throttle opening calculation unit, 580 is a lateral G vehicle speed correction amount calculation unit, 590 is a vehicle speed command value change amount determination unit, 600
Is a driving wheel acceleration calculation unit, 610 is a vehicle speed control stop determination unit,
Reference numeral 620 is a vehicle speed control interruption determination unit, 630 is a brake pressure command value calculation unit, and the configuration and operation of each block in FIG. 1 will be described below.

First, the vehicle speed command maximum value setting process of FIG. 1 will be described. When a system switch (not shown) is turned on, the power of the entire apparatus is turned on and the system enters a standby state. Then, when the set switch 20 is turned on in this state, the vehicle speed control is started in the vehicle speed control unit 500 (the portion surrounded by the broken line) including the microcomputer and its peripheral components.

The vehicle speed command maximum value setting unit 520 sets the actual vehicle speed VA (t) when the set switch 20 is pressed as the vehicle speed command maximum value VSmax (target vehicle speed). The actual vehicle speed VA (t) is the actual speed of the vehicle detected by the vehicle speed sensor 10 from the number of rotations of the tire. Further, after the vehicle speed command maximum value VSmax is set by the set switch 20 as described above, each time the coast switch 30 is pressed once,
The vehicle speed command maximum value setting unit 520 determines the vehicle speed command maximum value VSmax.
Is set to a lower value by 5 km / h. That is, when the button is pressed n times, it is set to a low value of n × 5 km / h (when the pressing time is t when the pressing is continued, for example, t / 10 msec × 5 km / h). Further, after the vehicle speed command maximum value VSmax is set by the set switch 20 as described above, the vehicle speed command maximum value setting unit 520 sets the vehicle speed command maximum value VSmax to 5 km / every time the accelerator switch 40 is pressed once. Set a high value for each h. In other words, if you press n times, n × 5 km / h (If you continue to press, the pressing time is t, for example, t / 1
It is set to a high value of 0 msec x 5 km / h).

Next, the lateral G vehicle speed correction amount calculation processing of FIG. 1 will be described. The lateral G vehicle speed correction amount calculation unit 580 uses the steering angle θ of the steering wheel output from the steering angle sensor 100.
(t) and the actual vehicle speed VA (t) are input, and a vehicle speed correction amount VSUB (t) for correcting a vehicle speed command value described later according to lateral acceleration (hereinafter referred to as lateral G) is calculated. . Note that the lateral G vehicle speed correction amount calculation unit 580, specifically, as shown in FIG.
The steering angle signal LPF (low-pass filter) unit 581, the lateral G calculation unit 582, and the vehicle speed correction amount calculation map 583 are included.

First, the steering angle signal LPF section 581
The actual vehicle speed VA (t) and the steering angle θ (t) are input, and the steering angle LP
The F value θLPF (t) is calculated. The steering angle LPF value θLPF (t) is
It is expressed by the following formula. θLPF (t) = θ (t) / (TSTR · s + 1) where s is a differential operator (the same applies in the following equation).
Here, the time constant TSTR of the LPF is represented by TSTR = 1 / (2π · fc), and the cutoff frequency fc of the LPF is, as shown in FIG. 3, the cutoff frequency fc with respect to the actual vehicle speed VA (t).
Determined by the map of. In this map, the cutoff frequency fc is set lower as the vehicle speed increases. For example, 100 km / h has a lower value than 50 km / h.

The lateral G calculating unit 582 inputs the steering angle LPF value θLPF (t) and the actual vehicle speed VA (t), and calculates the lateral G value YG (t) according to the following equation. YG (t) = {VA (t) ² · θLPF (t)} / {N ・ W ・ [1 + A ・ VA
(t) ² ]} where W is the vehicle wheel base, N is the steering ratio, and A is the stability factor. The above equation shows the case where the lateral G is detected from the steering angle. However, when the lateral G is detected by applying the low-pass filter to the yaw rate ψ (t) using the yaw rate sensor, the following expression is used. You can use it. YG (t) = VA (t) ・ ψLPF ψLPF = ψ (t) / (TYAW ・ s + 1) However, TYAW is the time constant of the low-pass filter, and the larger the actual vehicle speed VA (t), the larger the value. .

The vehicle speed correction amount calculation map 583 has a lateral G
Value YG (t) is input to calculate a vehicle speed correction amount VSUB (t) for correcting the vehicle speed command value. The vehicle speed correction amount VSUB (t) is calculated by multiplying the correction coefficient determined by the lateral G by a predetermined vehicle speed command value change amount limit value, for example, 0.021 km / 10 msec (= 0.06 G). The vehicle speed command value change amount limit value is equal to the maximum value of the vehicle speed command value change amount ΔVCOM (t) described later. VSUB (t) = correction coefficient × 0.021 (km / 10msec) As will be described later, when the vehicle speed command value VCOM (t) that finally becomes a value for controlling the vehicle speed is calculated, the above vehicle speed correction amount VSU
B (t) is added as a subtraction term. Therefore, the larger the vehicle speed correction amount VSUB (t) is, the more the vehicle speed command value VCOM (t) is limited. As shown in FIG. 4, the correction coefficient increases as the lateral G value YG (t) increases. This is because the vehicle speed command value VCOM (t) is more restricted as the lateral G becomes larger. However, as shown in FIG.
Is 0.1 G or less, it is determined that the correction of the vehicle speed command value VCOM (t) is not necessary, and the correction coefficient is set to zero. When the lateral G becomes 0.3G abnormal, it is a value that does not occur in normal use, and in order to prevent the correction amount from becoming excessively large when the lateral G detection value accidentally increases, 0.3G In the above, the correction coefficient is constant (for example, 2.0).

As will be described later in detail in the vehicle speed command value determining unit 510, when the target vehicle speed is increased by operating the accelerator switch 40, that is, when acceleration is requested, the last final vehicle speed command is issued. Value VCOM (ts
The vehicle speed command value change amount ΔVCOM (t) is added to (t) and the vehicle speed correction value VSUB (t) is subtracted from the reference vehicle speed command value VCO.
MB (t) is calculated. Therefore, the vehicle speed command value change amount ΔVC
If OM (t) is larger than the vehicle speed correction value VSUB (t), acceleration is performed, and if it is small, deceleration is performed. The vehicle speed correction value VSUB (t) is obtained by multiplying the vehicle speed command value change amount limit value (the maximum value of the vehicle speed command value change amount) by a correction coefficient as shown in FIG. In the case where the command value change amount limit value = the vehicle speed command value change amount, when the correction coefficient is 1 (YG (t) = 0.2 in the example of FIG. 4), the acceleration amount and the deceleration amount are equal to each other. Vehicle speed is maintained. That is, in this example, when the lateral G value YG (t) is smaller than 0.2, the acceleration is performed, and when it is large, the deceleration is performed. Further, when the target vehicle speed is reduced by operating the coast switch 30, that is, when deceleration is requested, the vehicle speed command value change amount ΔVCOM (t) and the vehicle speed correction value are calculated from the current actual vehicle speed VA (t). By subtracting VSUB (t) from the vehicle speed command value VCOM
(t) is calculated. Therefore, in this case, the vehicle is always decelerated, but the degree of deceleration increases as the vehicle speed correction value VSUB (t) increases, that is, the lateral G increases. Note that the above-mentioned value 0.021 for the vehicle speed command value change amount limit value
(km / 10msec) is a value assuming use on a highway.

As described above, the vehicle speed correction value VSUB (t) is
Obtained by the product of the correction coefficient according to the lateral G and the vehicle speed command value change amount limit value, and when the lateral G increases, the subtraction term (vehicle speed correction value)
The vehicle speed is controlled so that the value of does not increase and the lateral G does not increase. However, the steering angle signal LPF unit 581 of FIG.
As described above, the higher the vehicle speed range, the cutoff frequency f
Since c is made low, the time constant TSTR of the LPF becomes large, the steering angle LPF value θLPF (t) becomes small, and the lateral G estimated by the lateral G calculation unit 582 also becomes small. As a result,
Since the vehicle speed correction value VSUB (t) obtained via the vehicle speed correction amount calculation map 583 becomes small, it becomes difficult to apply the correction to the vehicle speed command value (correction in the acceleration decreasing direction) by the steering angle.

Explaining this point in detail, the characteristic of the natural frequency ωnSTR of the vehicle response to the steering angle is shown by the following equation. ωnSTR = (2W / VA) √ {Kf ・ Kr ・ (1 + A ・ VA ² ) / mV
・ I} However, Kf and Kr are front and rear tire cornering power (for one wheel), W is a wheel base, mV is a vehicle mass, A
Is a stability factor and I is a vehicle yaw moment of inertia.

As shown in FIG. 5, the characteristic of the natural frequency ωnSTR is that the natural frequency ωnSTR decreases as the vehicle speed VA increases, and the vehicle response to the steering angle deteriorates, while the natural frequency ωnSTR decreases as the vehicle speed VA decreases. It can be seen that the frequency ωnSTR increases and the vehicle response to the steering angle improves. That is, in the higher vehicle speed range, lateral G is less likely to occur even when steering is performed, and in the lower vehicle speed range, lateral G is more likely to occur even with a little steering. Therefore, as shown in FIG. 3, the cutoff frequency fc is set lower in the higher vehicle speed range, so that the response is slowed and the vehicle speed command value due to the steering angle is less likely to be corrected.

Next, the process for determining the vehicle speed command value change amount shown in FIG. 1 will be described. The vehicle speed command value change amount determination unit 590
Calculates the vehicle speed command value variation amount ΔVCOM (t) from the map shown in FIG. 6 based on the absolute value of the deviation between the actual vehicle speed VA (t) and the vehicle speed command maximum value VSmax. This map is such that the absolute value of the deviation does not exceed the acceleration limit value α described in the vehicle speed control stop determination unit 610 within a certain range (range B in FIG. 6).
The larger the absolute value is, the larger the vehicle speed command value change amount ΔVCOM (t) is to accelerate or decelerate as quickly as possible. And
The vehicle speed command value change amount ΔVCOM (t) is made small so that the sense of acceleration is not impaired as the absolute value of the deviation is smaller, so that the vehicle speed command maximum value VSmax is not overshot. In a range where the absolute value of the deviation is large (range A in FIG. 6), the acceleration limit value α does not exceed a constant value (for example, 0.
06G). Further, in a small range (range C in FIG. 6), it is set to a constant value (for example, 0.03G).

Further, the vehicle speed command value change amount determining unit 590 monitors the vehicle speed correction value VSUB (t) output from the lateral G vehicle speed correction amount calculating unit 580, and the vehicle speed correction value VSUB is obtained.
When (t) once becomes non-zero and then returns to zero again, it is determined that the traveling on the curved road is completed, and the actual vehicle speed VA (t) becomes equal to the vehicle speed command maximum value VSmax. Is detected.

If it is determined that the curve ends,
Based on the absolute value of the deviation between the actual vehicle speed VA (t) and the vehicle speed command maximum value VSmax, the vehicle speed command value change amount Δ is calculated using FIG.
Instead of determining VCOM (t), the vehicle speed command value change amount ΔV from the actual vehicle speed VA (t) when it is determined that the curve has ended
Determine COM (t). As the characteristics at that time, characteristics showing the same tendency as in FIG. 6 are used. That is, the horizontal axis of FIG.
Instead of VSmax |, a map (not shown) changed to the actual vehicle speed VA (t) is used, and the smaller the actual vehicle speed VA (t), the smaller the vehicle speed command value change amount ΔVCOM (t) is set. It has the specified characteristics. Then, this processing is performed at the actual vehicle speed VA.
When (t) becomes equal to the vehicle speed command maximum value VSmax, the process ends.

Incidentally, the vehicle speed correction value VSUB (t) is replaced by the vehicle speed correction value VSUB (t) instead of the above example in which the vehicle speed command value variation amount ΔVCOM (t) is determined from the actual vehicle speed VA (t) when it is determined that the curve has ended. When the value becomes a value other than zero, it is determined that traveling on a curved road is started, and the actual vehicle speed VA (start) at that time is stored in advance,
And the actual vehicle speed VA when it is determined that the curved road has ended
difference from (end) ΔVA = VA (start) −VA (end) (that is,
The vehicle speed command value variation amount ΔVCOM (t) may be determined from the magnitude of the vehicle speed command value correction amount). As the characteristic at this time, a characteristic showing a tendency opposite to that of FIG. 6 is used. That is, a map (not shown) in which the horizontal axis of FIG. 6 is changed to the vehicle speed difference ΔVA instead of | VA−VSmax | is used, and the vehicle speed command value change amount ΔVCOM (t) increases as the vehicle speed difference ΔVA increases. Is set to take a small value. In addition, this process is
The process ends when the actual vehicle speed VA (t) and the vehicle speed command maximum value VSmax become equal.

When traveling on a curved road, the vehicle speed command value is corrected so that the lateral G value does not become excessively large, so that the vehicle speed generally decreases. Therefore, as described above, after the vehicle finishes traveling on the curved road and the vehicle speed drops, the actual vehicle speed VA (t) at the end of the curved road, or at the start and the end of the curved road (the vehicle speed command value is corrected to correct the vehicle speed). Vehicle speed difference between before and after
The vehicle speed command value change amount ΔVCOM (t) is changed according to the magnitude of A.

If the vehicle speed is low at the end of the curved road or the vehicle speed difference ΔVA is large, it is estimated that the vehicle speed has dropped because the radius of curvature of the curve is small (the curve is tight). If the curved road is continuous (for example, an S-shaped curve), the above situation is likely to occur. Therefore, when the vehicle speed is low at the end of the curved road or the vehicle speed difference ΔVA is large, the vehicle speed command value change amount ΔVCOM (t) is reduced to reduce the acceleration of the vehicle speed control based on the vehicle speed command value. As a result, in a continuous curve (S-shaped road), large acceleration is not performed every time the curve is turned. Similarly, if the vehicle speed is high at the end of the curved road or the vehicle speed difference ΔVA is small, it is determined that the vehicle is a single curve, and the vehicle speed command value change amount Δ
Increase VCOM (t). As a result, since the vehicle is accelerated immediately after the end of a single curve, there is no fear that the acceleration will be slow and the driver will feel uncomfortable.

Next, the vehicle speed command value determination processing of FIG. 1 will be described. The vehicle speed command value determination unit 510 determines the actual vehicle speed VA
(t), vehicle speed correction value VSUB (t), vehicle speed command value change amount ΔVCOM
(t), estimated acceleration value αV (t), acceleration command value αCOM (t) are input, and final vehicle speed command value VCOM (t) and initialization determination flag V
_INI_FLG is output to the drive torque command value calculation unit 530.
Note that, as shown in FIG. 7, the vehicle speed command value determination unit 510 specifically includes a reference vehicle speed command value calculation unit 511, an initialization determination unit 512, a road surface gradient estimation unit 513, and a vehicle speed command initial value setting unit. 514 and a final vehicle speed command value determination unit 515.

In the reference vehicle speed command value calculation unit 511, the last final vehicle speed command value VCOM (t-st) and the vehicle speed command value change amount Δ
Based on VCOM (t) and the vehicle speed correction value VSUB (t), the current reference vehicle speed command value VCOMB (t) is calculated based on the following equation. VCOMB (t) = VCOM (t-st) + ΔVCOM (t) −VSUB (t) where st is a sampling period.

Whether the initialization determination unit 512 initializes the reference vehicle speed command value VCOMB (t), the actual vehicle speed VA (t), and the vehicle speed command value change amount ΔVCOM (t) based on the following conditions: Determine whether or not.・ VCOMB (t)> VA (t) and ΔVCOM (t) <ΔVCOM_th
In case of V_INI_FLG = 1 (initialize) ・ Other than that V_INI_FLG = 0 (do not initialize) However, ΔVCOM_th is a threshold value for deceleration for judging initialization (for example, -0.6 Gm / s ² Equivalent value).

The road surface slope estimating section 513 estimates the road surface slope currently running and obtains a slope estimated value Ri (t). Here, although details of the road surface gradient estimation method are omitted, for example, from the deviation between the acceleration command value αCOM (t) and the actual acceleration (estimated acceleration value αV (t) or acceleration detection value), There is a method of calculating the estimated value Ri (t). Also,
There is also a method of obtaining it from position information from a sensor that detects a gradient or a navigation system.

The vehicle speed command initial value setting unit 514 sets the final vehicle speed command initial value VCOM_INI (t) based on the actual vehicle speed VA (t), the acceleration estimated value αV (t) and the gradient estimated value Ri (t). To do. The method will be described later in detail.

The final vehicle speed command value determining unit 515 determines the reference vehicle speed command value VCOMB (t) and the final vehicle speed command initial value VCOM_INI depending on the state of the initialization determination flag V_INI_FLG.
Either one of (t) is selected as the final vehicle speed command value VCOM (t).

Next, details of the vehicle speed command initial value setting unit 514 will be described. The final vehicle speed command initial value VCOM_INI (t) set here is, as shown in FIG.
The vehicle speed command initial value reference value VCOM_INI_B (t) is calculated from A (t), and the final initial value is the result obtained by adding corrections according to the running conditions such as the estimated gradient value Ri (t) and the estimated acceleration value αV (t). Set as a value. Hereinafter, each part will be described.

The vehicle speed command initial value reference value calculation unit 514-a calculates the vehicle speed command initial value reference value VCOM_INI_ from the actual vehicle speed VA (t).
B (t) is calculated, but the vehicle speed command initial value reference value VCOM_INI_B
(t) is set so that the optimum deceleration timing can be obtained when traveling on a flat road and the acceleration before deceleration start (before initialization) is an intermediate value (about 0.5 m / s ² ). To do. As a calculation method, for example, there is a method of obtaining from the actual vehicle speed VA (t) and a preset offset value VCOM_OFF by the following equation. VCOM_INI_B (t) = VA (t) −VCOM_OFF However, VCOM_OFF is an offset value (for example, 1.0 km /
h).

The vehicle speed command initial value correction value calculation unit 514-b calculates the vehicle speed command initial value correction value VCOM_INI_C (t) from the traveling state such as the gradient estimated value Ri (t) and the acceleration estimated value αV (t). Hereinafter, the method will be described in detail. 1) Calculation of the correction value VCOM_INI_C1 (t) based on the road surface slope The correction value VCOM_INI_C1 for the road surface slope is input based on the preset map shown in FIG. 9 using the estimated slope value Ri (t) calculated by the method described above as an input. Calculate (t). 2) Acceleration estimated value αV of a predetermined time T_A before (for example, 1.0 [sec] before) the time when the calculation initialization determination flag V_INI_FLG of the correction value VCOM_INI_C2 (t) due to acceleration is set
Using (t-T_A) as an input, the correction value VCOM_INI_C2 (t) for the acceleration is calculated based on the map shown in FIG. Each correction value VCOM_INI_C1 (t) calculated by the above method,
Also, the final vehicle speed command initial value correction value VCOM_INI_C (t) is calculated by the following formula, which is the sum of VCOM_INI_C2 (t) and VCOM_INI_C (t) = VCOM_INI_C1 (t) + VCOM_INI_C2 (t).
Is calculated.

In the final vehicle speed command initial value calculation unit 514-c,
From the vehicle speed command initial value reference value VCOM_INI_B (t) determined by the vehicle speed command initial value reference value calculation unit 514-a, the vehicle speed command initial value correction value VCOM_ determined by the vehicle speed command initial value correction value calculation unit 514-b
The final vehicle speed command initial value VCOM_INI (t) is calculated by the following formula, which is obtained by subtracting INI_C (t): VCOM_INI (t) = VCOM_INI_B (t) -VCOM_INI_C (t).

Next, the drive torque command value calculation process of FIG. 1 will be described. The drive torque command value calculation unit 530
Calculates the drive torque command value dFC (t) for achieving the final vehicle speed command value VCOM (t). Further, it is determined from the state of the initialization determination flag V_INI_FLG whether to initialize the internal state. Note that FIG. 11 shows the drive torque command value calculation unit 53.
It is a block diagram which shows an example of a structure of 0.

First, the final vehicle speed command value VCOM (t) is input.
However, the transfer characteristic GV (s) when the actual vehicle speed VA (t) is output
Can be expressed by the following formula. GV (s) = 1 / (TV ・ s + 1) ・ e^{(-LV / S)} Where TV is the primary delay time constant and LV is the power train system.
Is a dead time due to the delay.

The vehicle model to be controlled is modeled with the drive torque command value dFC (t) as the manipulated variable and the actual vehicle speed VA (t) as the controlled variable. It can be expressed by a simple linear model shown in the equation. VA (t) = 1 / (mV ・ Rt ・ s) e ^{(-LV / S)}・ dFC
(t) where Rt is the effective turning radius of the tire and mV is the vehicle mass. As described above, the vehicle model that receives the drive torque command value dFC (t) and outputs the actual vehicle speed VA (t) has the integral characteristic because it has the form of 1 / s.

The characteristic of the controlled object includes the dead time LV due to the delay of the power train system, and the nonlinear characteristic in which the value of the actual vehicle speed VA (t) changes depending on the actuator or engine used is approximated to be described later. By using the disturbance estimator based on the zeroing method, the vehicle model in which the driving torque command value dFC (t) is input and the actual vehicle speed VA (t) is output can be expressed by the same equation as above.

Here, input the final vehicle speed command value VCOM (t)
However, the response characteristics of the controlled object when the actual vehicle speed VA (t) is output
Of the primary delay time constant TV and dead time LV
When the characteristics of the transfer characteristic GV (s) having the element are matched, the result shown in FIG.
As shown in₁(s), C _Two(s), C_ThreeUsing (s),
It can be defined as follows. However, C₁(s),
C_Two(s) shows the disturbance estimator by the approximate zeroing method.
To suppress the effects of disturbances and modeling errors.
It is a compensator and C_Three(s) is based on the model matching method.
Shows the compensator. Compensator C₁(s) ＝ e^{(-LV / S)}/ (TH · s + 1) Compensator C_Two(s) = (mV ・ Rt ・ s) / (TH ・ s + 1) At this time, the estimated disturbance value dV (t) is dV (t) = C_Two(s) ・ VA (t) -C₁(s) ・ dFC (t) Becomes In addition, ignoring the dead time of the controlled object,
First-order low-pass filter of time constant TV of Dell GV (s)
And compensator C_Three(s) is the following constant. Compensator C_Three(s) = mV ・ Rt / TV C above₁(s), C_Two(s), C_Three(s) compensator
The dynamic torque command value dFC (t) is calculated by the following equation. dFC (t) = C_Three(s) ・ {VCOM (t) -VA (t)}-{C_Two(s) ・ VA
(t) -C₁(s) ・ dFC (t)} Based on the drive torque command value dFC (t)
Control. That is, it is measured in advance as shown in FIG.
Driving torque finger using the engine nonlinear steady-state characteristic map
To make the actual driving torque dFA (t) match the command value dFC (t).
Calculate the throttle opening command value, and
If the drive torque is insufficient, use a transmission or brake
To distribute. In this way, throttle opening, shifting
Engine by controlling the machine and brake
Non-linear steady-state characteristics can be linearized.

When the continuously variable transmission 70 has a fluid converter with a lockup clutch, the lockup state signal LU is output from the controller of the continuously variable transmission 70.
When s is input and it is determined that the unlocked state is entered, the time constant TH (C ₁ (s), C ₂ (s) in FIG. 11 is
Increase the value in the denominator of. As a result, the vehicle speed control feedback correction amount (the correction coefficient of the feedback loop for maintaining the desired response characteristic) becomes small, and it is possible to match the response characteristic of the control target that is delayed during unlocking compared with during lockup, When up,
The stability of the vehicle speed control system is secured during unlocking.

Further, in the drive torque command value calculation unit 530 shown in FIG. 11, the compensator C ₁ (s) and the compensator C ₂ (s) for compensating the transfer characteristic of the controlled object are determined by the designer. The compensator C ₃ (s) for achieving the response characteristic is used. However, as shown in FIG. 13, the pre-compensator C _F for compensating the response characteristic as desired by the designer is used. (s), a reference model calculation unit C _R (s) for calculating an arbitrary response characteristic defined by the designer, and a feedback compensation for compensating a deviation amount from the response characteristic of the reference model calculation unit C _R (s). C on the bowl
It can also be configured by ₃ (s) '.

The front compensator C _F (s) has a final vehicle speed command value VC
In order to achieve the transfer function GV (s) of the actual vehicle speed VA (t) with respect to OM (t), the reference drive torque command value dFC1 (t) is calculated using the filter shown by the following equation. dFC1 (t) = mV · RT · s · VCOM (t) / (TV · s + 1) reference model calculating section _{C R} (s) is a target response VT of the vehicle speed control system
(t) is calculated from the transfer function GV (s) and the final vehicle speed command value VCOM (t). That is, VT (t) = GV (s) .VCOM (t).

The feedback compensator C ₃ (s) 'corrects the drive torque command value so as to eliminate the deviation when there is a deviation between the target response VT (t) and the actual vehicle speed VA (t). The quantity dV (t) 'is calculated. That is, dV (t) 'is represented by the following formula. dV (t) '= {( KP · s + KI) / s} · {VT (t) -VA (t)} However, KP is a feedback compensator C _{3 (s)'} proportional control gain, KI feedback It is an integral control gain of the compensator C ₃ (s) ′. The drive torque command value correction amount dV
(t) 'corresponds to the estimated disturbance value dV (t) described in FIG. At this time, when it is determined by the lockup state signal Lus that the lockup state is in the unlocked state, the correction amount dV (t) ′ is calculated. That is, dV (t) '= {(KP' * s + KI ') / s} * {VT (t) -VA
(t)}. However, since KP '<KP and KI'<KI, the feedback gain becomes small. Therefore, the drive torque command value dFC (t) is the reference drive torque command value dFC1 (t).
And the drive torque command value correction amount dV (t) ', dFC (t) = dFC1 (t) + dV (t)' is calculated. In this way, the feedback gain is made smaller during unlocking than during lockup, so the speed of change in the drive torque command value correction amount is small, and the response characteristics of the control target that lag behind in unlocking compared to during lockup Therefore, the stability of the vehicle speed control system can be secured during both lockup and unlockup.

Next, the actuator drive system of FIG. 1 will be described. The shift command value calculation unit 540 uses the drive torque command value dFC (t), the actual vehicle speed VA (t), and the coast switch 3
The output of 0 and the output of the accelerator pedal sensor 90 are input, the shift command value DRATIO (t) is calculated as follows, and output to the continuously variable transmission 70.

(1) Based on the actual vehicle speed VA (t) when the coast switch 30 is off and the drive torque command value dFC (t), the throttle opening estimation value TVOEST1 is calculated from the throttle opening estimation map as shown in FIG. To calculate. Next, the engine speed command value NIN_COM is calculated from the CVT shift map as shown in FIG. 15 based on the estimated throttle opening value TVOEST1 and the actual vehicle speed VA (t). Then, the shift command value DRATIO (t) is equal to the actual vehicle speed VA (t) and the engine speed command value N.
Calculate from IN_COM using the following formula. DRATIO (t) = NIN_COM ・ 2π ・ Rt / {60 ・ VA (t) ・ G
f} where Gf is the final gear ratio.

(2) When the coast switch 30 is on When the coast switch 30 is turned on, the vehicle speed command maximum value VSM
When AX is lowered, the shift command value DRATIO (t)
The previous shift command value DRATIO (t-1) is retained. for that reason,
Even when the coast switch 30 is continuously turned on, the gear shift command value retains the previous value, that is, the value immediately before the coast switch 30 is turned on, until the coast switch 30 is turned off. Therefore, when the set vehicle speed is returned to the set vehicle speed by the accelerator switch 40 after being greatly reduced, even if the throttle opening is controlled to open in order to accelerate, the engine speed rapidly increases in the state where the downshift is not performed. Never be,
It is possible to prevent the generation of noise to the driver.

The actual gear ratio calculating section 550 is an expression based on the engine speed NE (t) detected by the engine rotation sensor 80 from the ignition signal of the engine and the actual vehicle speed VA (t), RATIO (t) = NE ( The actual gear ratio RATIO (t) is calculated according to t) / {VA (t) · Gf · 2π · Rt}.

The engine torque command value calculator 560
Is an equation based on the drive torque command value dFC (t) and the actual gear ratio RATIO (t), and TECOM (t) = dFC (t) / {Gf · RATIO (t)}, the engine torque command value TECOM (t ) Is calculated.

The target throttle opening calculation unit 570 is
Engine torque command value TECOM (t) and engine speed N
Based on E (t), the target throttle opening TVOCOM is calculated from the engine total performance map as shown in FIG.
Output to the throttle actuator 60.

The brake pressure command value calculation unit 630 obtains the engine brake torque TECOM '(t) when the throttle is fully closed from the engine total performance map as shown in FIG. 16 based on the engine speed NE (t). , A brake pressure command value REFPBRK (t) is calculated from the engine brake torque TECOM '(t) and the engine torque command value TECOM (t) by the following equation, and is output to the brake actuator 50. REFPBRK (t) = {TECOM (t) -TECOM '(t)} ・ Gm ・ Gf
/ {4 ・ (2 ・ AB ・ RB ・ μB)} where Gm is the gear ratio of the automatic transmission, AB is the wheel cylinder force (cylinder pressure x area), RB is the disc rotor effective radius, and μB is the pad friction coefficient. is there.

Next, the vehicle speed control interruption processing of FIG. 1 will be described. The vehicle speed control interruption determination unit 620 inputs the accelerator operation amount APO detected by the accelerator pedal sensor 90 and compares the accelerator operation amount APO with a predetermined value. This predetermined value is the accelerator operation amount APO1 corresponding to the target throttle opening TVOCOM input from the target throttle opening calculation unit 570, that is, the value of the accelerator opening corresponding to the automatically controlled vehicle speed at that time. And
When the accelerator operation amount APO is larger than the above predetermined amount,
In other words, by the driver stepping on the accelerator pedal,
When the throttle opening is opened more than the throttle opening by the throttle actuator 60 at that time, the vehicle speed control interruption signal is output.

Then, in response to the vehicle speed control interruption signal, the drive torque command value calculation section 530 and the target throttle opening degree calculation section 570 initialize the calculation up to that point, and the continuously variable transmission is driven at a constant speed by the transmission controller. The shift map is switched to the normal travel shift map. That is, the constant speed traveling by the automatic control is interrupted and the normal traveling control corresponding to the driver's accelerator operation is performed.

The continuously variable transmission 70 has a normal travel speed change map and a constant speed travel speed change map. When the constant speed travel control is interrupted, the vehicle speed control device sends the transmission to the transmission and the constant speed travel speed change map normally. Instruct to switch to the shift map for driving. Here, the shift map for normal traveling is, for example, a steep (good responsiveness) control map so that the downshift does not become slower during acceleration, and the shift map for constant speed traveling is such that the acceleration / deceleration change does not become large. In addition, the control map is set so that the responsiveness is suppressed as compared with that during acceleration, so that the driver does not feel uncomfortable when switching from constant speed driving to normal driving.

Further, the vehicle speed control interruption determining unit 620 stops the output of the vehicle speed control interruption signal when the accelerator operation amount APO returns below a predetermined value, and the actual vehicle speed VA (t) is the vehicle speed command maximum value VSMAX. If it is larger than the above, the deceleration request is output to the drive torque command value calculation unit 530. Then, the drive torque command value calculation unit 530 causes the vehicle speed control interruption determination unit 620.
When the output of the vehicle speed control interruption signal from the vehicle is stopped and the deceleration request is input, the calculated driving force command value dFC
In order to realize (t) with the throttle, deceleration control is performed with the throttle opening calculated by the target throttle opening calculation unit 570. However, when the braking force is not sufficient only by fully closing the throttle, the throttle and the gear ratio are used. Downhill road,
Regardless of whether the road is flat, the gear ratio command value calculation unit 540 outputs the gear ratio command value DRATIO (shift down request),
The downshift control of the continuously variable transmission 70 is performed so as to compensate for the insufficient braking force.

The driving (braking in this case) force command value d
When FC (t) is large and the braking force due to the downshift of the continuously variable transmission 70 has an upper limit, the braking force is supplemented by normal braking on a flat road, but on a downhill road, the drive torque command value calculation unit 530 A brake control prohibition signal BP is output to the brake pressure command value calculation unit 630 to prohibit the brake control on a downhill road. The reason for controlling in this way is as follows. That is, since it may be necessary to continuously apply the brake when decelerating with the brake on the downhill road, the throttle opening and the downshift control of the continuously variable transmission 70 are performed on the downhill road as described above. By controlling so as to obtain a required braking force only by deceleration, braking is performed without using a brake.

By the above method, even when the driver temporarily depresses the accelerator pedal to accelerate the vehicle and the constant speed traveling control is interrupted, and then the constant speed traveling control is resumed, the transmission shifts. By the down, a deceleration larger than the deceleration only by the throttle opening fully closing control can be obtained, so that the convergence time to the target vehicle speed can be shortened. Further, by using the continuously variable transmission 70, a shift shock does not occur even on a long downhill, it is larger than the deceleration only by the throttle opening fully closing control, and is based on the vehicle speed command value change amount ΔVCOM. Since the throttle and the gear ratio are controlled so as to realize the driving torque, it is possible to smoothly decelerate while maintaining a predetermined deceleration. Incidentally, since a shock is generated at the time of downshifting in a normal stepped transmission, only the throttle control is conventionally performed and the downshift control of the transmission is not performed even when the deceleration control request is large as described above. However, since the downshift can be smoothly performed by using the continuously variable transmission 70, by performing the above control, it is possible to smoothly decelerate at a deceleration equal to or more than the deceleration only for the throttle opening fully closing control.

Next, the vehicle speed control stop processing of FIG. 1 will be described. The driving wheel acceleration calculation unit 600 calculates the actual vehicle speed VA
Input (t) and drive wheel acceleration αOBS (t)
Is calculated. αOBS (t) = {KOBS · s / (TOBS · s ² + s + KOBS)} ・
VA (t) where KOBS is a constant and TOBS is a time constant. Since the actual vehicle speed VA (t) is a value calculated from the rotational speed of the tire (driving wheel) as described above, this value itself is a value corresponding to the rotational speed of the driving wheel. Acceleration αOB
S (t) is a value obtained by obtaining the amount of change in vehicle speed (driving wheel acceleration) from the driving wheel speed VA (t).

Then, the vehicle speed control stop determination unit 610.
Is the drive wheel acceleration α obtained by the drive wheel acceleration calculation unit 600.
OBS (t) is compared with a predetermined acceleration limit value α (this acceleration is a value corresponding to the amount of change in vehicle speed, for example, 0.2 G), and the driving wheel acceleration α OBS (t) exceeds the acceleration limit value α. If the vehicle speed control is stopped, a vehicle speed control stop signal is output. Based on this vehicle speed control stop signal, the drive torque command value calculation unit 530 and the target throttle opening degree calculation unit 570 initialize the calculation. Note that once the vehicle speed control is stopped, the vehicle speed control does not return until the set switch 20 is turned on again.

Since the apparatus shown in FIG. 1 is a system for controlling the vehicle speed by the vehicle speed command value based on the vehicle speed command value variation amount ΔVCOM determined by the vehicle speed command value variation amount determining unit 590, the vehicle speed is controlled in the normal state. Command value change amount limit value, for example, 0.
There is no change in vehicle speed exceeding 06G = 0.021 (km / 10msec).
Therefore, the drive wheel acceleration α OBS (t) is larger than the predetermined acceleration limit value α greater than the value corresponding to the vehicle speed command value change amount limit value.
When it exceeds (for example, 0.2 G), it is highly possible that the drive wheels have slipped. In this way, by comparing the driving wheel acceleration αOBS (t) with the predetermined acceleration limit value α, it is possible to detect the occurrence of slip. Therefore, a normal vehicle speed sensor (rotational speed of the drive wheel) is not provided without separately providing an acceleration sensor for slip suppression control such as TCS (traction control system) or detecting the rotational speed difference between the drive wheel and the driven wheel. By determining the driving wheel acceleration αOBS (t) based on the output from the sensor for detecting the slip), it is possible to make a slip determination and a control suspension determination. Also, by increasing the vehicle speed command value change amount ΔVCOM, the responsiveness to the target vehicle speed can be improved. It should be noted that instead of judging the suspension of the constant speed traveling control by comparing the driving wheel acceleration αOBS (t) with a predetermined value, the vehicle speed command value change amount ΔV calculated by the vehicle speed command value change amount determining section 590 is calculated.
The control may be stopped when the difference between COM and the driving wheel acceleration αOBS (t) exceeds a predetermined value.

Next, the operation will be described. Hereinafter, a vehicle speed command value determination operation performed by the vehicle speed command value determination unit 510 when shifting from acceleration to deceleration will be described.

In the time chart shown in FIG. 17, the road gradient has a negative value (downhill), and the estimated acceleration value αV before initialization is relatively large (rapid acceleration). Time t1_1
Acceleration starts from and the vehicle runs on a downhill from time t1_2. After that, the vehicle transitions from acceleration to deceleration at time t1_3
Initialization condition (VCOMB (t)> VA (t) and ΔVCOM (t)
<ΔVCOM_th) is satisfied, and the final vehicle speed command value VCOM (t) is switched to the initial value VCOM_INI.

That is, from the gradient estimation value Ri = -5% at the time of initialization (time t1_3) and the acceleration estimation value αV = 1.0 m / sec ² 1.0 [sec] before the initialization, FIG. 9 and FIG. Initial value correction value VCOM_INI_C calculated based on the map shown is 1.5km
Since it is / h, the final initial value VCOM_INI is VA (t1-3)
-2.5km / h. As a result, it is possible to perform deceleration without causing a problem such as delay in deceleration timing or insufficient initial deceleration.

The time chart shown in FIG. 18 shows a traveling pattern from acceleration to deceleration as in FIG. 17, but the road gradient is a positive value (uphill), and the acceleration estimated value αV before initialization is compared. It is relatively small (slow acceleration). Acceleration starts at time t2_1 and the road surface slope becomes a positive value (uphill) from time t2_2. After that, the vehicle shifts from acceleration to deceleration, and at time t2_3, the initialization condition (VCOMB (t)> VA
(t) and ΔVCOM (t) <ΔVCOM_th are satisfied, and the final vehicle speed command value VCOM (t) is switched to the initial value VCOM_INI.

That is, from the gradient estimation value Ri = + 5% at the time of initialization (time t2_3) and the acceleration estimation value αV = 0.4 m / sec ² 1.0 [sec] before the initialization, FIG. 9 and FIG. The initial value correction value VCOM_INI_C calculated based on the map shown is 0.5km
Since it is / h, the final initial value VCOM_INI is VA (t2-3)
-0.5km / h. As a result, the deceleration can be performed without causing the problem that the deceleration timing is too early.

FIG. 19 is a time chart showing the vehicle speed, drive torque command value, and inter-vehicle distance under the same running conditions (road slope) as in the prior art shown in FIGS. 22 and 23. In the traveling pattern that shifts from to deceleration, the vehicle speed command value at the time of initialization determination t1 is set to a value lower than the vehicle speed command value on the flat road, so the drive torque command value after initialization is on the flat road. The driving torque command value is lower than the driving torque command value of FIG. 22 and delay of deceleration timing as shown in FIG. 22 is prevented, and as a result, there is no possibility that the inter-vehicle distance from the preceding vehicle is reduced and the driver feels uncomfortable. , Keep a proper distance between you and the preceding vehicle. On the contrary, in the traveling pattern in which the vehicle shifts from acceleration to deceleration on an uphill road, the vehicle speed command value at the time of initialization determination t1 is set to a value higher than the vehicle speed command value on a flat road. Drive torque command value is higher than the drive torque command value on a flat road, and deceleration as shown in FIG. 23 is prevented from being prematurely accelerated. As a result, the inter-vehicle distance from the preceding vehicle is increased and the acceleration is accelerated. There is no risk of the driver feeling insufficient, and the inter-vehicle distance from the preceding vehicle is maintained appropriately. That is, it is possible to decelerate at the same deceleration timing regardless of the road surface gradient.

FIG. 20 is a time chart showing the vehicle speed, the drive torque command value, and the inter-vehicle distance under the same running conditions (abrupt acceleration before initialization) as in the prior art shown in FIG.
In the driving pattern that shifts from the rapid acceleration state before initialization to deceleration, the vehicle speed command value at t1 at the time of initialization determination is set to a value lower than the vehicle speed command value at intermediate acceleration, so drive after initialization The torque command value becomes a value lower than the drive torque command value at the intermediate acceleration, and the delay of the deceleration timing as shown in FIG. 24 is prevented, and as a result, the inter-vehicle distance from the preceding vehicle decreases and the driver feels uncomfortable. There is no possibility of giving it, and the inter-vehicle distance from the preceding vehicle is maintained properly.

FIG. 21 is a time chart showing the vehicle speed, drive torque command value, and inter-vehicle distance under the same running conditions (slow acceleration before initialization) as in the prior art shown in FIG.
In the traveling pattern that shifts from the slow acceleration state before initialization to deceleration, the vehicle speed command value at t1 at the time of initialization determination is set to a value higher than the vehicle speed command value at intermediate acceleration, so drive after initialization It is prevented that the torque command value becomes higher than the drive torque command value at the intermediate acceleration, and the deceleration as shown in FIG. 25 is prevented from prematurely. As a result, the inter-vehicle distance with the preceding vehicle increases and the feeling of insufficient acceleration is felt. There is no risk of giving the driver a proper distance from the preceding vehicle. That is, it is possible to decelerate at the same deceleration timing regardless of the acceleration before initialization.

Next, the effect will be described.

(1) The gradient estimated value Ri (t) from the road surface gradient estimation unit 513 is input and compared with a flat road to obtain the gradient estimated value Ri (t).
Indicates an uphill, the final vehicle speed command initial value VCOM_INI
Since the vehicle speed command initial value setting unit 514 for setting the final vehicle speed command initial value VCOM_INI (t) to a low value is provided when (t) is set high and the estimated slope value Ri (t) indicates a downhill, The final vehicle speed command value V is set by setting the conversion flag V_INI_FLG
When the final vehicle speed command initial value VCOM_INI (t) is selected as COM (t), the deceleration timing on the uphill is too early, the acceleration is insufficient due to initial overdeceleration, and the deceleration timing on the downhill is delayed or initial. The problem that the driver feels uncomfortable as the inter-vehicle distance decreases due to insufficient deceleration can be solved.

(2) The vehicle speed command initial value setting unit 514 sets the estimated vehicle speed command initial value VCOM_INI_ (t) to the optimum vehicle speed command initial value VCOM_INI_ (t) so as to obtain optimum deceleration while traveling on a flat road. When t) indicates an uphill, the final vehicle speed command initial value VCO
A correction is made to make M_INI (t) higher, and when the estimated slope value Ri indicates a downhill, a correction is made to make the final vehicle speed command initial value VCOM_INI (t) low, so that a flat road is used as a reference. By correcting the vehicle speed command initial value, it is possible to obtain a feeling of deceleration that matches the driver's feeling regardless of the road surface gradient.

(3) When the estimated acceleration value αV before a predetermined time before initialization is input, and the estimated acceleration value αV indicates a small acceleration, the final vehicle speed command initial value VCOM_INI (t) is set higher, If the estimated acceleration value αV indicates a large sudden acceleration, the vehicle speed command initial value setting unit 514 that sets the final vehicle speed command initial value VCOM_INI (t) to a low value is provided. Therefore, the final vehicle speed command value is set by setting the initialization determination flag V_INI_FLG. When the final vehicle speed command initial value VCOM_INI (t) is selected as VCOM (t),
Before the initialization judgment, the deceleration timing for slow acceleration is too early, or there is a feeling of insufficient acceleration due to initial excessive deceleration. It is possible to improve the problem that the driver feels uncomfortable.

(4) The vehicle speed command initial value setting unit 514 is set so that optimum deceleration is obtained when the estimated acceleration value αV before the predetermined time for initialization is an intermediate value. When the estimated acceleration value αV is small with respect to the reference value VCOM_INI_ (t) and indicates slow acceleration, the final vehicle speed command initial value VCOM_
If a high acceleration INI (t) is added and the estimated acceleration value αV indicates a large sudden acceleration, the final vehicle speed command initial value VCOM_IN
Since I (t) is corrected to be low, by correcting the vehicle speed command initial value based on the intermediate acceleration, it is possible to obtain a feeling of deceleration that matches the driver's feeling regardless of the acceleration before initialization. .

(5) The vehicle speed command initial value setting unit 514 is adapted to obtain the optimum deceleration timing when the vehicle is traveling on a flat road and the acceleration before the predetermined time for initialization has an intermediate value. Vehicle speed command initial value reference value VCOM_INI_B (t) vehicle speed command value initial value reference value calculation unit 514-a, road surface gradient correction value VCOM_INI_C1 (t) and acceleration correction value VCOM
The result of adding _INI_C2 (t) is the final initial value correction value V
COM_INI_C (t) vehicle speed command initial value correction value calculation unit 514
-b and the final vehicle speed command initial value calculation unit 514 that calculates the vehicle speed command initial value VCOM_INI (t) by subtracting the final initial value correction value VCOM_INI_C (t) from the vehicle speed command initial value reference value VCOM_INI_B (t) Since the configuration has c, it is possible to obtain an appropriate deceleration timing and initial deceleration regardless of the road surface gradient, and also to obtain an appropriate deceleration feeling regardless of the acceleration before initialization.

(6) The initialization determination unit 512 determines that the reference vehicle speed command value VCONMB (t) exceeds the actual vehicle speed VA (t) and the vehicle speed command value change amount ΔVCOM (t) is initialized. Initialization deceleration threshold ΔVCOM_th, the initialization determination flag V_I
Since NI_FLG is set, the final vehicle speed command value VCOM is set at once by setting the initialization determination flag V_INI_FLG.
(t) is changed to the vehicle speed command initial value VCOM_INI (t), and the actual vehicle speed VA
(t) can be quickly converged to the target vehicle speed.

(Other Embodiments) The vehicle speed control device of the present invention has been described above based on the first embodiment. However, the specific structure is not limited to this first embodiment.
Modifications and additions of the design are allowed without departing from the gist of the invention according to each claim of the claims.

For example, in the first embodiment, an example of the vehicle speed control device for performing the constant speed traveling control is shown. However, if there is no preceding vehicle, the constant speed traveling control is performed with the target vehicle speed, and if there is a preceding vehicle, the target vehicle speed is controlled. It can also be applied to an inter-vehicle vehicle speed control device that travels while maintaining a set inter-vehicle distance from a preceding vehicle with the vehicle speed as the upper limit speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a vehicle speed control device of a first embodiment.

FIG. 2 is a block diagram showing a lateral G vehicle speed correction amount calculation unit of the first embodiment device.

FIG. 3 is a cutoff frequency characteristic diagram of a low-pass filter used in the steering angle signal LPF unit of the first embodiment device.

FIG. 4 is a correction coefficient characteristic diagram with respect to a lateral G for calculating a vehicle speed correction amount in the first embodiment device.

FIG. 5 is a characteristic diagram showing the relationship between the natural frequency and the actual vehicle speed in the first embodiment device.

FIG. 6 is a characteristic diagram of a vehicle speed command value change amount with respect to an absolute value of a deviation between an actual vehicle speed and a vehicle speed command maximum value in the first embodiment device.

FIG. 7 is a block diagram showing a vehicle speed command value determination unit of the first embodiment device.

FIG. 8 is a block diagram showing a vehicle speed command initial value setting unit of the first embodiment device.

FIG. 9 is a diagram showing an example of a map of a correction amount with respect to a gradient estimated value in the first embodiment device.

FIG. 10 is a diagram showing an example of a map of a correction amount with respect to an estimated acceleration value in the first embodiment device.

FIG. 11 is a block diagram showing a drive torque command value calculation unit of the first embodiment device.

FIG. 12 is a diagram showing an example of an engine nonlinear steady-state characteristic map.

FIG. 13 is a block diagram illustrating another configuration example of a drive torque command value calculation unit.

FIG. 14 is a diagram showing a throttle opening estimation map.

FIG. 15 is a diagram showing an example of a CVT shift map.

FIG. 16 is a diagram showing an example of an engine total performance map.

FIG. 17 is a time chart diagram showing a vehicle speed, an estimated acceleration value, and an estimated gradient value when the vehicle travels on a traveling road that is a downhill from a flat road in a traveling pattern that shifts from acceleration to deceleration in the first embodiment device.

FIG. 18 is a time chart diagram showing a vehicle speed, an estimated acceleration value, and an estimated gradient value when the vehicle travels on a traveling road from a flat road to an uphill in a traveling pattern that shifts from acceleration to deceleration in the first embodiment device.

FIG. 19 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when the vehicle travels on a traveling road having different road surface gradients in a traveling pattern in which the road surface gradient is changed from acceleration to deceleration in the first embodiment device.

FIG. 20 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when traveling in a traveling pattern in which acceleration is performed before deceleration in the apparatus of the first embodiment when the acceleration is rapid before initialization.

FIG. 21 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when traveling in a traveling pattern in which acceleration is performed before deceleration in the apparatus of the first embodiment when the acceleration is slow before initialization.

FIG. 22 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when traveling in a traveling pattern in which a vehicle speed control device of a prior art moves downhill from acceleration to deceleration.

FIG. 23 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when traveling in a traveling pattern in which an uphill shifts from acceleration to deceleration in a vehicle speed control device of a prior art.

FIG. 24 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when traveling in a traveling pattern in which transition is made from acceleration to deceleration when the vehicle speed control device of the prior art is in rapid acceleration before initialization.

FIG. 25 is a time chart diagram showing a vehicle speed, a drive torque command value, and an inter-vehicle distance when traveling in a traveling pattern in which transition from acceleration to deceleration is made in the case where the vehicle speed control device of the prior art is slow acceleration before initialization.

[Explanation of symbols]

10 vehicle speed sensor 20 set switch 30 coast switch 40 accelerator switch 50 brake actuator (vehicle speed control actuator) 60 throttle actuator (vehicle speed control actuator) 70 continuously variable transmission (vehicle speed control actuator) 80 engine rotation sensor 90 accelerator pedal sensor 100 steering angle Sensor 500 Vehicle speed control unit 510 Vehicle speed command value determination unit (vehicle speed command value determination unit) 511 Reference vehicle speed command value calculation unit 512 Initialization determination unit 513 Road surface slope estimation unit 514 Vehicle speed command initial value setting unit 514-a Vehicle speed command initial value reference Value calculation unit 514-b Vehicle speed command initial value correction value calculation unit 514-c Final vehicle speed command initial value calculation unit 515 Final vehicle speed command value determination unit 520 Vehicle speed command maximum value setting unit 530 Driving torque command value calculation unit (driving torque command value Calculation means) 54 Gear shift command value calculation unit (actuator command value calculation unit) 550 Actual gear ratio calculation unit 560 Engine torque command value calculation unit (actuator command value calculation unit) 570 Target throttle opening calculation unit 580 Lateral G vehicle speed correction amount calculation unit 590 Vehicle speed command Value change amount determination unit 600 Driven wheel acceleration calculation unit 610 Vehicle speed control stop determination unit 620 Vehicle speed control interruption determination unit 630 Brake pressure command value calculation unit

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Claims (6)

[Claims] 1. A vehicle speed command value determining means for calculating a vehicle speed command value so as to eliminate a deviation between a target vehicle speed and an actual vehicle speed, and a drive torque command value is calculated based on the vehicle speed command value from the vehicle speed command value determining means. In a vehicle speed control device comprising: a driving torque command value calculating means, and an actuator command value calculating means for calculating a command value to the vehicle speed control actuator based on the driving torque command value from the driving torque command value calculating means, The vehicle speed command value determining means includes a reference vehicle speed command value calculation unit that calculates a reference vehicle speed command value from a vehicle speed command value change amount, and an initialization determination that determines whether to initialize the vehicle speed command value and the drive torque command value. Section, a road surface slope estimating unit that estimates the road surface slope, and a slope estimated value from the road surface slope estimating unit are input and compared with a flat road, and when the slope estimated value indicates an uphill vehicle speed command initial Is set higher and the vehicle speed command initial value setting unit that sets a lower vehicle speed command initial value when the estimated slope value indicates a downhill, and the reference vehicle speed command by the initialization determination signal from the initialization determination unit. A final vehicle speed command value determining section that determines a final vehicle speed command value by selecting either the reference vehicle speed command value from the value calculation section or the vehicle speed command initial value from the vehicle speed command initial value setting section. Characteristic vehicle speed control device. 2. The vehicle speed control device according to claim 1, wherein the vehicle speed command initial value setting unit is set to a vehicle speed command initial value reference value set so as to obtain optimum deceleration while traveling on a flat road. When the estimated slope value indicates an uphill, a correction for increasing the vehicle speed command initial value is added, and when the estimated slope value indicates a downhill, a correction for lowering the vehicle speed command initial value is added. Vehicle speed control device. 3. A vehicle speed command value determining means for calculating a vehicle speed command value so as to eliminate a deviation between a target vehicle speed and an actual vehicle speed, and a drive torque command value is calculated based on the vehicle speed command value from the vehicle speed command value determining means. In a vehicle speed control device comprising: a driving torque command value calculating means, and an actuator command value calculating means for calculating a command value to the vehicle speed control actuator based on the driving torque command value from the driving torque command value calculating means, The vehicle speed command value determining means includes a reference vehicle speed command value calculation unit that calculates a reference vehicle speed command value from a vehicle speed command value change amount, and an initialization determination that determines whether to initialize the vehicle speed command value and the drive torque command value. Section, an acceleration estimation section that estimates the vehicle acceleration, and an acceleration estimation value input a predetermined time before initialization is input from the acceleration estimation section, and when the acceleration estimation value indicates a small acceleration, A vehicle speed command initial value setting unit that sets the vehicle speed command initial value to a high value and sets the vehicle speed command initial value to a low value when the estimated acceleration value indicates a large acceleration, and an initialization determination signal from the initialization determination unit. The final vehicle speed command value determination unit that determines either the reference vehicle speed command value from the reference vehicle speed command value calculation unit or the vehicle speed command initial value from the vehicle speed command initial value setting unit to determine the final vehicle speed command value. A vehicle speed control device comprising: 4. The vehicle speed control device according to claim 3, wherein the vehicle speed command initial value setting unit obtains optimum deceleration when the estimated acceleration value before a predetermined time before initialization is an intermediate value. To the vehicle speed command initial value reference value that is set as described above, if the acceleration estimated value shows a small acceleration, a correction to increase the vehicle speed command initial value is added, and if the acceleration estimated value shows a large acceleration, A vehicle speed control device characterized by adding a correction for lowering a vehicle speed command initial value. 5. The vehicle speed control device according to any one of claims 1 to 4, wherein the vehicle speed command initial value setting unit is traveling on a flat road and has an acceleration before a predetermined time before initialization. When the value is an intermediate value, the vehicle speed command initial value reference value calculation unit that calculates the vehicle speed command initial value reference value so that optimum deceleration is obtained, and the correction value by the road slope and the correction value by the acceleration are added. The vehicle speed command initial value correction value calculation unit that uses the result as the final initial value correction value, and the final vehicle speed command initial value that calculates the vehicle speed command initial value by subtracting the final initial value correction value from the vehicle speed command initial value reference value A vehicle speed control device having a value calculator. 6. The vehicle speed control device according to claim 1, wherein the initialization determination unit determines that the reference vehicle speed command value exceeds the actual vehicle speed, and the vehicle speed command value change amount is A vehicle speed control device, which outputs an initialization determination signal when it is less than a deceleration threshold value for determining initialization.