JP2004352117A - Vehicular traveling control device and parking support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular traveling control device and a parking support device capable of carrying out certain travelling control by accurately detecting a tilt angle of a vehicle. <P>SOLUTION: The parking support device S is provided with a braking oil pressure detecting sensor 3 for detecting control amount of a vehicular braking device. On the basis of the control amount of the braking device detected by the braking oil pressure detecting sensor 3, a tilt state of a vehicle V is estimated, and according to the tilt state of the vehicle V, creeping force of a driving power device 5 is adjusted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle control device and a parking assist device including the vehicle control device.
[0002]
[Prior art]
Various technologies for controlling the vehicle speed within a predetermined range when the vehicle is traveling are known. In a relatively high vehicle speed region, an automatic cruise device that obtains a predetermined vehicle speed by automatically adjusting an accelerator opening is known. ing. On the other hand, as a vehicle speed control technique at the time of slow running, there is, for example, a running control device disclosed in JP-A-2002-89314. When the vehicle is determined to be in the automatic traveling mode, the traveling control device increases the engine rotation speed to a predetermined rotation speed that is larger than the time of idling, and when the vehicle runs at the predetermined rotation speed. The braking force of the vehicle is controlled such that the actual vehicle speed of the vehicle becomes a preset target vehicle speed. Further, the traveling control device is provided with slope determining means for determining whether or not the traveling path of the vehicle is a sloping road, and the driving control of the vehicle is performed according to whether or not the traveling path of the vehicle is a sloping road. It controls the force and the braking force.
[0003]
[Patent Document 1]
JP-A-2002-89314
[Problems to be solved by the invention]
However, the traveling control device disclosed in Patent Literature 1 detects the speed and acceleration of the vehicle and determines whether the vehicle is on a slope by using the speed and acceleration. Since the slope of the slope is often at most several degrees at the most, the accuracy of estimating such a small angle of slope using the speed and acceleration of the vehicle is low.
[0005]
In particular, when trying to stop a vehicle having a parking assist device having such a travel control device in a parking lot, the parking lot may have a road surface gradient such as an uphill or downhill. If the road surface is an uphill, creep running may not be possible, and conversely, vehicle speed control becomes difficult when descending. Under such circumstances, it is desired to accurately grasp the road surface gradient or the vehicle inclination state on the road surface.
[0006]
Therefore, an object of the present invention is to provide a vehicle traveling control device and a parking assist device that can perform reliable traveling control by accurately detecting the inclination angle of a vehicle.
[0007]
[Means for Solving the Problems]
A vehicle travel control device according to the present invention that has solved the above-mentioned problems is a vehicle travel control device that performs drive control of a vehicle by applying a driving torque to the vehicle, wherein the vehicle travel control device detects a vehicle stop state, and the vehicle stops. Braking control amount detection means for detecting a control amount of the braking device of the vehicle at the time of transition from the state to the start state, and a tilt state for estimating the tilt state of the vehicle based on the control amount of the braking device in the start state of the vehicle Estimating means.
[0008]
In addition, a parking assist device according to the present invention that has solved the above-mentioned problems provides a parking assist device that applies driving torque to a vehicle to perform traveling control of the vehicle and assists movement of the vehicle to a target parking position. Based on the braking control amount when the vehicle is in the starting state, a braking control amount detecting unit that detects the control amount of the braking device of the vehicle when the vehicle transitions from the stopped state to the starting state, and And a control state setting means for setting a control state in traveling control in accordance with the estimated inclination state.
[0009]
In the vehicle traveling control device and the parking assist device according to the present invention, the inclination state of the vehicle is estimated based on the control amount of the braking device in the starting state of the vehicle. For this reason, even in the case of a road surface condition with a small inclination, the inclination can be regarded as a change in the control amount of the braking device, so that the inclination state of the vehicle can be accurately detected. As a result, reliable travel control and parking support can be performed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, the same reference numerals are given to portions having the same function, and overlapping description may be omitted.
[0011]
FIG. 1 is a block diagram of a parking assist device including a vehicle traveling control device according to an embodiment of the present invention. As shown in FIG. 1, the parking assist device S according to the present embodiment includes a parking assist ECU 1. The parking assist ECU 1 includes a CPU, a ROM, a RAM, an input signal circuit, an output signal circuit, a power supply circuit, and the like, and performs various arithmetic processes. By this calculation processing, the estimation of the road surface gradient and the judgment of the change request of the creep force are performed.
[0012]
Further, the parking assist device S includes a braking oil pressure detection sensor 2 and a vehicle speed detection sensor 3. The brake oil pressure detection sensor 2 includes, for example, a brake pedal stroke sensor attached to a brake pedal provided in a vehicle (not shown), and detects an operation amount of the brake pedal. The brake oil pressure detection sensor 2 outputs the detected operation amount to the parking assist ECU 1, and the parking assist ECU 1 calculates the braking oil pressure applied to the brake based on the operation amount of the brake pedal. The vehicle speed detection sensor 3 is, for example, a vehicle speed sensor provided on wheels of an automobile, and detects the speed of the vehicle. The vehicle speed detection sensor 3 constitutes the vehicle stop state detection means of the present invention, and detects the vehicle stop state when the vehicle speed detected by the vehicle speed detection sensor 3 is zero.
[0013]
Further, the parking assist device S includes an engine ECU 4 and a driving power unit 5. The engine ECU 4 includes a CPU, a ROM, a RAM, an input signal circuit, an output signal circuit, and a power supply circuit, and changes the creep force of the driving power unit 5 based on a creep force change signal output from the parking assist ECU 1. And outputs a creep force change signal to be adjusted. The driving power unit 5 includes, for example, an engine and an E / V motor, and increases or decreases the creep force based on the creep force change signal output from the engine ECU 4. In the driving power unit 5, parking assistance is performed by automatically driving the vehicle. Further, when performing automatic traveling by the parking assist device S, the vehicle is caused to travel using only the creep force of the driving power device 5 as the driving force.
[0014]
Further, the parking assist ECU 1 is provided with a road surface gradient estimating unit 11, which is a slope state estimating unit of the present invention, a necessary creep force estimating unit 12, and a creep force change request determining unit 13, which is a control state setting unit of the present invention. ing.
[0015]
The road surface gradient estimating unit 11 stores in advance the braking oil pressure when a vehicle on a horizontal road surface starts from a stopped state. The road surface gradient estimating unit 11 calculates the braking oil pressure when the vehicle starts from the operation amount of the brake pedal output from the braking oil pressure detection sensor 2 and estimates the road surface gradient from the difference from the braking oil pressure stored in advance. are doing. The road surface gradient estimated here is equivalent to the inclination state of the vehicle. The road surface gradient estimating unit 11 outputs the estimated road surface gradient to the necessary creep force estimating unit 12.
[0016]
The required creep force estimating unit 12 estimates the creep force required for the driving power unit 5 based on the road surface gradient estimated by the road surface gradient estimating unit 11, and uses the estimated required creep force as a creep force change request determination unit 13. Output to The creep force change request determination unit 13 stores the creep force of the driving power unit 5, compares the stored creep force with the output required creep force, and determines whether the creep force needs to be changed. Judge. If it is determined that the creep force needs to be changed, the creep force estimated by the necessary creep force estimating unit 12 is output to the engine ECU 4.
[0017]
A procedure of parking assistance by the parking assistance device according to the present embodiment having the above configuration will be described. FIG. 2 is a flowchart illustrating a procedure of parking assistance according to the present embodiment.
[0018]
As shown in FIG. 2, when parking assistance is started, first, it is determined that the vehicle is in a stopped state (S1). The fact that the vehicle is in a stopped state is confirmed by recognizing that the vehicle speed output from the vehicle speed detection sensor 3 is 0 in the road surface gradient estimating unit 11 of the parking assist device S.
[0019]
When the vehicle is in a stopped state, a brake hydraulic pressure P1 at which the vehicle starts to move is calculated (S2). In calculating the brake oil pressure P1 at which the vehicle starts moving, the brake oil pressure detection sensor 2 detects the operation amount of the brake pedal, and the vehicle speed detection sensor 3 detects the speed of the vehicle. The road surface gradient estimating unit 11 in the parking assist ECU 1 monitors the operation amount output from the braking oil pressure detection sensor 2 and the vehicle speed signal output from the vehicle speed detection sensor 3. At first, the vehicle is stopped by the driver stepping on the brake, and from this state, the driver gradually releases the brake pedal, and the vehicle starts moving. When the vehicle starts moving, the detected vehicle speed does not become 0, and the road surface gradient estimating unit 11 calculates the braking oil pressure applied to the brake from the operation amount of the brake pedal at the time when the vehicle speed stops becoming 0.
[0020]
When the braking oil pressure P1 is calculated in this way, the road surface gradient estimating unit 11 compares the previously stored braking oil pressure P0 when the vehicle on the horizontal road surface starts from a stopped state with the calculated braking oil pressure, and calculates a difference. The pressure ΔP is calculated (S3). After obtaining the differential pressure ΔP, the road surface gradient θ is estimated from the vehicle specifications determined by the differential pressure ΔP and the weight of the vehicle by the following equation (1) (S4).
[0021]
θ = sin ⁻¹ ((a / W) × ΔP) (1)
Here, θ: road gradient a: constant indicating the relationship between the braking oil pressure and the braking force W: weight of the vehicle When the road gradient is estimated, the estimated road gradient is output to the required creep force estimating unit 12 and the required creep force is calculated. The estimating unit 12 calculates a required creep force from the output road surface gradient (S5). Here, the relationship between the road surface gradient and the creep force will be described with reference to FIGS. FIG. 3 is a graph showing the relationship between the braking oil pressure and the braking / driving force on a flat road, and FIG. 4 is a graph showing the relationship between the braking oil pressure and the braking / driving force on an inclined road surface.
[0022]
In order for the vehicle to start, the creep force needs to exceed a value obtained by adding the starting braking force and the running resistance. The braking force for stopping the vehicle moves up and down in proportion to the braking oil pressure as shown in FIG. For example, when the driver depresses the brake pedal to stop the vehicle, the braking hydraulic pressure and the braking force are large. On the other hand, the vehicle is constantly subjected to the creep force by the driving power unit 5, and when the creep force is smaller than the sum of the braking force and the running resistance, the vehicle is in a stopped state. From this state, when the driver trying to start the vehicle gradually releases the brake pedal to reduce the braking oil pressure, the braking force decreases together with the braking oil pressure. Then, when the braking oil pressure and the braking force decrease as they are, the braking force reaches the starting braking force, and the value obtained by adding the braking force and the running resistance falls below the creep force, the vehicle starts. The road surface gradient estimating unit 11 stores the braking oil pressure P0 at this time as the braking oil pressure at the time of starting.
[0023]
When the vehicle is stopped on an inclined road surface, as shown in FIG. 4, the starting braking force changes according to the gradient of the road surface. For example, as shown in FIG. 5, it is assumed that the vehicle V is stopped on a road surface having a road surface gradient θ. When θ = 0 °, the state is the same as the state shown in FIG. When θ <0 °, the weight of the vehicle V is assumed to be W, and if the vehicle V is retracted and parking is performed, the force of W sin θ is applied to the vehicle V in the forward direction by gravity, so that the starting braking force is reduced. It becomes smaller, and the starting brake oil pressure P1 when the vehicle V actually starts becomes smaller than the start braking oil pressure P0 when the vehicle V is flat. However, since gravity is applied in the forward direction, the necessary creep force required to start the vehicle increases. Conversely, when θ <0 °, the force of Wsin θ is applied to the vehicle V in the backward direction due to gravity, so the starting braking force increases, and the braking oil pressure P1 when the vehicle V starts moving increases. However, since the gravity is applied in the backward direction, the required creep force is reduced.
[0024]
Here, when the actual creep force is small despite the large required creep force, it is difficult to make the vehicle V run stably, and furthermore, it becomes impossible to make the vehicle V run. Conceivable. On the other hand, if the required creep force is small but the actual creep force is large, the running speed of the vehicle V may be too fast, and stable running control may be difficult.
[0025]
Then, returning to the flow of FIG. 3, after calculating the required creep force in step S5, the creep force change request determination unit 13 compares the calculated required creep force with the current creep force of the driving power unit 5. . If the required creep force is greater than the current creep force, the creep force is changed so that the creep force is increased, and if the required creep force is smaller than the current creep force, the creep force is reduced. The requested creep force change signal is output to the engine ECU 4 (S5). The engine ECU 4 changes the creep force of the driving power unit 5 based on the output creep force change signal.
[0026]
For example, when the driving power unit 5 is an engine, the creep force can be changed by changing the idle speed of the engine. When the drive power unit 5 is a motor, the creep force can be changed by increasing or decreasing the drive current for driving the motor. Further, the creep force here may be changed in a stepless manner, or may be changed in several steps according to the magnitude of the road surface gradient θ.
[0027]
As described above, in the parking assist device S according to the present embodiment, the road surface gradient is estimated from the difference between the braking oil pressure when the vehicle starts moving and the braking oil pressure on the flat road stored in advance. Then, the required creep force is calculated from the estimated road surface gradient, the presence or absence of a change in the creep force is determined, and the driving power unit is controlled. For this reason, even in the case of a road surface condition with a small inclination, the inclination can be regarded as a change in the control amount of the braking device, so that the inclination state of the vehicle can be accurately detected. Then, since the creep force is changed according to the inclination state, it is possible to perform reliable parking support.
[0028]
The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the parking assist device is described as an example. However, the present invention can be used for traveling control during normal traveling, for example, traveling control in so-called auto cruise. In the above embodiment, the braking oil pressure is calculated from the operation amount of the brake pedal. However, the braking oil pressure may be calculated by another method, or the braking oil pressure may be directly detected. Further, in the above embodiment, the creep force is changed in accordance with the inclination state. However, the creep force may not be changed, for example, the driver may be notified and the drive force may be increased. .
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a vehicle traveling control device and a parking assist device that can perform reliable traveling control by accurately detecting the inclination angle of a vehicle.
[Brief description of the drawings]
FIG. 1 is a block diagram of a parking assist device including a vehicle travel control device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a procedure of parking assistance according to the embodiment.
FIG. 3 is a graph showing a relationship between braking hydraulic pressure and braking / driving force on a flat road.
FIG. 4 is a graph showing a relationship between braking hydraulic pressure and braking / driving force on an inclined road surface.
FIG. 5 is a diagram showing a force relationship applied to a vehicle on an inclined road surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Parking assistance ECU, 2 ... Brake hydraulic pressure detection sensor, 3 ... Vehicle speed detection sensor, 4 ... Engine ECU, 5 ... Drive power unit, 11 ... Road surface gradient estimation unit, 12 ... Necessary creep force estimation unit, 13 ... Creep Power change request determination unit, S: parking support device, V: vehicle.

Claims (2)

In a vehicle travel control device that performs drive control of the vehicle by giving a drive torque to the vehicle,
Stopping state detecting means for detecting a stopping state of the vehicle,
Braking control amount detection means for detecting a control amount of a braking device of the vehicle when the vehicle transitions from a stopped state to a start state,
A tilt state estimating unit that estimates a tilt state of the vehicle based on a control amount of the braking device in a start state of the vehicle;
A vehicle travel control device comprising: In a parking assist device that provides driving torque to the vehicle to perform travel control of the vehicle, and assists movement of the vehicle to a target parking position.
Stopping state detecting means for detecting a stopping state of the vehicle,
Braking control amount detection means for detecting a control amount of a braking device of the vehicle when the vehicle transitions from a stopped state to a start state,
A tilt state estimating means for estimating a tilt state of the vehicle based on the braking control amount in a start state of the vehicle;
Control state setting means for setting a control state in traveling control in accordance with the estimated inclination state;
A parking assist device comprising:

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