JPH08541B2 - Vehicle travel correction device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel correction device that corrects a travel direction that is affected by an external disturbance while the vehicle is traveling.

[Conventional technology]

Generally, when a vehicle is subjected to a disturbance such as a side wind when traveling at a high speed, the disturbance affects the traveling of the vehicle and deteriorates the straight traveling performance of the vehicle. For this reason, conventionally, by detecting the cross wind received by the vehicle and correcting the steered rear wheels in accordance with the detection result, the straight running performance of the vehicle is maintained (for example, Japanese Patent Laid-Open No. 60-193776). Also, there has been devised one that detects the yaw rate or lateral acceleration applied to the vehicle and corrects and steers the wheels so as to eliminate the influence of the vehicle due to the disturbance during non-steering (for example, JP-A-60-161256). .

[Problems to be solved by the invention]

However, in the conventional type, when the driver's vehicle is consciously manipulating the vehicle, for example, when performing an operation such as acceleration, deceleration, or steering, the correction steering is automatically performed against the disturbance as described above. There is a problem that the driver feels uncomfortable due to the correction steering. Also, while the driver is consciously driving the vehicle, it is relatively easy for the driver to steer the steering wheel and correct the disturbance applied to the vehicle. The driver's attention tends to be distracted during steady-state running (running without acceleration or deceleration operation) using a device that automatically maintains a constant vehicle speed with a so-called auto drive device. However, there is a problem in that the straight running stability of the vehicle is impaired even when a relatively small disturbance such as a side wind acts.

The present invention has been made in view of the above problems, and when the driver intentionally steers the vehicle, the driver can steer without feeling any discomfort, and the vehicle is not affected by a disturbance such as a crosswind during steady running. An object of the present invention is to provide an optimal vehicle travel correction device that maintains the travel stability of the vehicle.

[Means for solving problems]

In order to solve the above-mentioned object, the present invention determines a steady running state in which the vehicle speed is substantially constant and generates a steady running signal, and a steady running state determining means, and a vehicle running based on the disturbance signal. Correction value calculation means for obtaining a travel correction value to correct the state, and when it is determined that the vehicle is in the steady travel state in response to the steady travel signal, the wheels are steered corresponding to the travel correction value, When it is determined that the vehicle is not in a steady traveling state, wheel steering means for prohibiting steering of the wheel by the traveling correction value is provided.

[Action / effect]

According to the above configuration of the vehicle travel correction device of the present invention, when the vehicle is in a steady running state in which the speed is substantially constant such that the driver does not perform acceleration or deceleration operation, this state is used as the steady running signal. By determining the steady running state, and for the disturbance that acts on the vehicle in this state, the running correction value is calculated to correct the vehicle running, and the wheels are steering-corrected. Modifications can be made to cancel the disturbances that act on the vehicle during travel.
Therefore, the present invention makes it possible to stabilize the running of the vehicle without being influenced by the disturbance by the wheel steering means even if the driver does not actively steer the disturbance, particularly during steady-state running where the driver's attention is likely to be distracted. At the same time, the driver can consciously control the vehicle, and at the time of non-steady running in which the driver is consciously controlling the vehicle, the correction due to the disturbance is not performed, so that there is an effect that the control can be performed without a sense of discomfort.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of this embodiment. An electric control unit (hereinafter, ECU) 17 including a microcomputer outputs signals from the accelerator sensor 1, the brake switch 2, the front wheel steering angle sensor 3, the vehicle speed sensor 4, the yaw rate sensor 5, the wind pressure sensor 6, and the auto drive switch 23. input. The accelerator sensor 1 generates an accelerator signal proportional to the depression amount of the accelerator pedal. The brake switch 2 generates a brake operation signal in conjunction with the brake operation, and the steering angle sensor 3
Generates a steering angle signal proportional to the steering angle of the steering wheel 20. The yaw rate sensor 5 is composed of a yaw rate gyro or the like, detects a rotational angular velocity (yaw rate) generated around the center of gravity of the vehicle when viewed from above, and generates a yaw rate signal. The wind pressure sensor 3 separately detects the wind speed and the wind direction as a wind speed signal and a wind direction signal respectively, and then generates a wind pressure signal by obtaining a wind pressure acting in a direction perpendicular to the traveling direction of the vehicle, that is, a lateral direction from both signals. . The wind pressure may be directly detected using a diaphragm or the like. When the auto drive switch 23 is turned on, the desired vehicle speed or the current vehicle speed is stored as the target vehicle speed, and the actuator (not shown) is driven so that the target vehicle speed and the actual vehicle speed substantially match. The actuator drives the throttle valve via a link mechanism (not shown). When the switch 23 is turned on, a constant speed signal is sent to the control device 17. The driver can turn off the auto drive switch 23.
In addition to the brake switch 2, clutch switch,
It is automatically released by the parking brake switch.

Reference numeral 16 denotes a hydraulic actuator including a hydraulic piston 16a and a hydraulic cylinder. An electric control device 17 controls the solenoid valves 9, 10, 14 to move the hydraulic piston 16a in the vehicle width direction to determine its position. Both ends of the hydraulic piston 16a have left and right suspension arms 21 (semi-trailing arms in this example).
Is connected to one end of each of the vehicle body mounting ends.
The vehicle body attachment ends of the suspension arms 21 are attached to the vehicle body via elastic bushes (not shown). As a result, the hydraulic piston 16a changes the angle of the suspension arm 21 by utilizing the deformation of the elastic bush, and steers the rear wheel 19.

Reference numeral 9 is a stop valve that controls opening and closing of communication between the hydraulic power source and the direction switching valve 10. Directional switching valve 10 is hydraulic actuator 16
Is a valve for switching and controlling the supply of hydraulic pressure to the two hydraulic chambers 16b, 16c, and is, for example, a spool valve having two electromagnetic solenoids 10a, 10b. Reference numeral 14 denotes a neutral valve, which communicates the two hydraulic chambers 16b and 16c of the hydraulic actuator 16 to return the rear wheel to the neutral position when the rear wheel steering control is not performed or when the electric control device 17 is abnormal. Reference numeral 15 is a piston position sensor for detecting the position of the hydraulic piston, which uses, for example, a sliding potentiometer. This signal corresponds to the steering angle of the rear wheels.

In addition, 13 is an oil tank, 12 is a hydraulic pump, and 11 is a motor for driving the oil pump. An accumulator 8 stores the hydraulic pressure generated by the oil pump. Reference numeral 7 is a hydraulic pressure sensor for detecting the hydraulic pressure in the accumulator chamber, and the electric control device 17 receives the signal and drives the motor 11. 20
Is a steering wheel, 18 is a front tire, and 19 is a rear tire.

FIG. 2 shows the configuration of the electric control device 17. 50 is a microcomputer, 52 is an A / D converter, 50
Is a circuit that shapes the signal from the vehicle speed sensor 4,
Reference numerals 5 and 56 are an analog input buffer, a digital input buffer, and an output buffer circuit, respectively. The ECU 17 receives a constant speed traveling signal from the automatic drive switch 23, or a vehicle speed signal from the vehicle speed sensor 4, a steering angle signal from the front wheel steering angle sensor 3 by a processing of a microcomputer 51 described later.
A steady running state is determined from signals such as an accelerator signal from the accelerator sensor 1 and a brake operation signal from the brake switch 2. When the control device 17 receives at least one of the yaw rate signal from the yaw rate sensor 5 and the wind pressure signal from the wind pressure sensor 6 in this steady running state, the control device 17 detects the disturbance acting on the vehicle, A corrected steering angle for correcting the traveling of the vehicle is obtained according to the disturbance, the valves 9, 10, 14 are controlled, and the rear wheels 19 are steered based on the corrected steering angle.

Next, the operation of the microcomputer 51 will be described in detail based on the flowchart shown in the drawing.

FIG. 3 shows the main routine, FIG. 4 shows an interrupt routine that is activated by interruption every 5 ms, FIG. 5 shows a vehicle speed interrupt routine that detects the vehicle speed, and FIG. 6 shows direction switching that controls output to a directional switching valve. The respective valve interrupt routines are shown below.

Referring to FIG. 3, in steps 300 and 301, initial processing, setting of various modes, and initialization of data are performed when the microcomputer is started.

In step 302 of the main routine, it is determined whether the running state of the vehicle is a steady running state based on the vehicle speed data and various data obtained in the interrupt routine described later.
The detailed steps of step 302 will be described with reference to FIG. 7. Step 302a determines whether or not there is a constant speed traveling signal from the automatic drive switch 23, and if YES, a flag F _ST = indicating a steady traveling state at step 302h. If it is 1 and NO, or if the automatic drive switch 23 is not provided, the process proceeds to step 302b. In steps 302b to 302g, when there is no constant speed running signal from the auto drive switch 23, it is determined whether or not the steady running state is based on the vehicle speed data S, the steering angle signal FWP, the accelerator signal ACCP brake operation signal B, the elapsed time T and the like. Then, in the steady traveling state, the flag F _ST = 1 is set in step 302h, and when the conditions in each step are not satisfied, the process proceeds to step 302i and the flag F _ST = 0 is set.

In step 302b, it is determined whether the vehicle speed data S calculated in the vehicle speed interrupt routine, which will be described later, is a high speed running at a predetermined vehicle speed L ₁ or higher. The vehicle speed L ₁ is preferably about 60 km / h or more in order to detect a high-speed running state that is easily affected by a disturbance such as a side wind. If the condition of step 302b is satisfied, the process proceeds to step 302c, and in step 302c, the change state (ΔS) of the vehicle speed, that is, the acceleration / deceleration state of the vehicle is determined. This compares the current vehicle speed data S _t with the previous vehicle speed data S _t-1 every one second, and if the difference ΔS = | S _t −S _t-1 | changes within a predetermined value L ₂ , It is determined that the vehicle is not in the acceleration / deceleration state and the vehicle is traveling at a constant speed, and the process proceeds to step 302d. In step 302d, the absolute value of the front wheel steering angle signal FWP is either less than the predetermined angle L _3, whether or not that is the steering is not performed straight traveling judges. The predetermined angle L ₃ is set around the play angle (about 10 °) of the steering hole. Steps 302e and 302f are provided to quickly determine the driver's intention to perform acceleration / deceleration operation from the accelerator signal ACCP and the brake operation signal B. In step 302e, changes in the accelerator signal ACCP are compared every 20 ms. , Its change ΔACCP
However, if the depression side is equal to or more than the predetermined value L ₄ (%), it is determined that the driver has an intention to accelerate, and the process proceeds to step 302i. If it is less than the predetermined value L ₄ , the process proceeds to step 302f. Further, in step 302f, when the brake operation signal 13 is OFF, it is determined that the driver does not have the intention to decelerate, and the process proceeds to step 302g. Here, the same determination as in steps 302e and 302f, that is, the determination as to whether the vehicle is traveling at a constant speed or traveling at an adjustable speed is performed using the vehicle speed data S at step 302c.
However, by using the accelerator signal and the brake operation signal, there is an advantage that the driver's intention of the acceleration / deceleration operation can be quickly detected before the vehicle speed data S changes. In step 302g,
It is determined whether or not the elapsed time T has passed the predetermined time L ₅ seconds or more while the conditions 302b to 302f are satisfied. This is to determine whether or not each of the conditions of steps 302b to 302f is constantly satisfied. Step 302 described above
With steps 302a and 302c, it is possible to reliably determine the constant speed running even if there is no auto drive switch or if it is in the OFF state. Further, since the accelerator signal ACCP and the brake operation signal are used in steps 302e and 302f,
Since the driver's intention of the acceleration / deceleration operation can be instantly judged before the vehicle speed S changes, the correction of the rear wheel steering can be promptly stopped based on the driver's intention. Needless to say, in step 302, at least one of steps 302c, 302e, 302f may be used to determine whether or not the vehicle is traveling at a substantially constant speed.

Next, in step 303 of FIG. 3, based on the oil pressure from the oil pressure sensor 7, as shown in FIG. 8, a hysteresis characteristic is provided at pressures P _l and P _h , and the energization of the hydraulic motor 11 is turned on. ,
It is controlled OFF.

Next, the interrupt routine of FIG. 4 will be described. Step 400 is an interrupt that is generated regularly, and the cycle in this example is 5
is ms. In step 401, it is determined whether any of steps 402, 403, 410, 420 or step 404 is performed every 10 ms. In step 404, signals from the accelerator sensor 1, front wheel steering sensors 3, hydraulic pressure sensor 7, piston position sensor 7 other than the yaw rate sensor 5 and the wind pressure sensor 6 are scheduled, A / D converted and read, and then main. Return to routine. In step 402, the signals from the yaw rate sensor 5 and the wind pressure sensor 6 are A / D converted and read. In step 403, the yaw rate signal y read from the yaw rate sensor 5 is averaged. For example, 9th
As shown in the figure, the yaw rate signal y ₁ ... y _n read every 10 ms
Among these, the yaw rate _n at that time point is obtained by averaging the past 10 pieces of data from the latest signal y _n . here,
_n = (y _n-9 + ... + y _n ) / 10. This is to prevent the influence of the noise component of the yaw rate signal y generated by the slight vibration of the vehicle.

Next, the disturbance determination step 410 will be described based on the detailed steps shown in FIG. In step 410a, it is determined whether or not the vehicle is in a steady running state, and if it is not (F _st =
(When 0) proceeds to steps 410b and 410c, clears the flag F _CON indicating that the rear wheel steering control is being performed to 0, stops the rear wheel steering control, and returns the rear wheel 19 to the neutral position. Each valve 9,
Control signals are generated at 10 and 14.

If F _st = 1 in step 410a, that is, if the vehicle is in a steady traveling state, the process proceeds to step 410d. In step 410d, when the signal Wp from the wind pressure sensor (Wp) is larger than the predetermined wind pressure K _{1, it} is determined that the vehicle will receive a side wind and the course will be disturbed. In step 410f, the flag F _CON = 1 is set to control the rear wheels. Enter the mode. If Wp <K _{1 in} step 410d, the process proceeds to step 410e, and the behavior of the vehicle is determined from the change Δ _n of the average value _n of the yaw rate signal. If Δ _n is a predetermined value K ₂ or more,
Proceeding to step 410f, the rear wheel steering control mode is entered. Here, Δ _n is _n = | y _i − _i-1 |, _i is the yaw rate average value at the present time obtained in step 403, and _i-1 is obtained in step 403 0.1 sec before the present time. The yaw rate average value is shown. So in step 410d,
Predict and judge the disturbance of the course of the vehicle due to the cross wind, and step 41
At 0e, the disturbance of the course of the vehicle caused by disturbances such as from the road surface other than the side wind is determined. In this example, both the wind pressure signal and the yaw rate signal are used to determine the disturbance that acts on or acts on the vehicle.However, only the wind pressure signal is used when traveling at high speed, and only the yaw rate signal is used when traveling at low speed. Good. This is because high-speed roads that can travel at high speeds generally have good road surface conditions, so the disturbance due to the crosswind is greater than the effect from the road surface, while the low-speed roads have worse road surface conditions than the highway. Is also based on the reason that the disturbance from the road surface is larger. In step 410g, the yaw rate data _n-1 0.1 seconds before the present time is stored as the yaw rate signal _B before the start of rear wheel steering. In step 410h, the rear wheel steering angle correction command value θ is calculated. The command value θ is the current vehicle speed data S and the wind pressure signal
An appropriate value is calculated according to Wp, etc.

If the conditions are not satisfied in steps 410d and 410e, the process proceeds to step 410i and the rear wheel control mode (F _CON = 1)
If F _CON = 1 then step 42
When it goes to 0 and F _CON = 0, the interrupt process is terminated and the process returns to the main routine.

Next, details of step 420 in FIG. 4 are shown in FIG.
In step 420, each solenoid valve is controlled, and the rear wheels are controlled to the correction command value θ until the current yaw rate data _i becomes equal to the yaw rate data _B before starting the rear wheel steering. In step 420a, it is determined whether or not _i = _B , and if _i = _B , the process proceeds to step 420b and step 42
At 0b, each valve is controlled so as to stop the rear wheel steering control, and at the same time, the neutral valve 14 is opened and returned to the neutral position. Also, in step 420c, F _CON = 0 is cleared. Meanwhile, step 420d
Then, the duty signal for driving the directional control valve 10 is calculated based on the difference between the command value θ and the actual rear wheel steering angle from the piston position sensor 15. At step 420e, a signal for opening the stop valve 9 and closing the neutral valve is generated.

 Next, the vehicle speed interruption routine will be described with reference to FIG.

An interrupt is generated at the rise (or fall) of the pulse from the vehicle speed sensor 4, and at step 500 the pulse interval t
measure _i . In step 501, if the pulse interval corresponds to a vehicle speed of 2 km / h or less, the process proceeds to step 504 and the microcomputer 51
The vehicle speed inside is set to 0 km / h to prevent the pulse interval detection counter from overflowing. Also, step 502,
At 503, the vehicle speed is calculated by averaging the vehicle speed pulse 4 and each pulse.

The directional control valve routine shown in FIG. 6 is executed at an interrupt of a predetermined cycle, and in step 600 a drive pulse for the directional control valve 10 is output. Here, the interrupt processing and the drive pulse in step 600 are used to generate a control pulse equal to the duty ratio calculated in step 420d.

As described above, the microcomputer 51 determines the steady running state from the constant speed running signal from the auto drive switch 23 or the signals from the vehicle speed sensor 4, the front wheel steering angle sensor 3, the brake switch 2, the accelerator sensor 1, etc. In this steady running state, when the vehicle is affected by the disturbance from the side surface of the side wind, the corrected steering angle θ of the rear wheels is automatically calculated, and the steering control is performed based on this corrected value. Therefore, the driver can drive the vehicle stably without steering the front wheels.

In the above embodiment, steps 410d and 410e in FIG.
In the above, both the wind pressure signal Wp and the yaw rate data Δ are used, but the disturbance may be determined using only one of them. When only the wind pressure signal Wp is used, steps 410e and 410g are omitted and step 410h is replaced with step 700 of FIG. 12 (a). In step 700, the command value θ of the rear wheel steering angle and the rear wheel control time T _R are calculated. The command value θ and the control time T _R are stored in advance as a map using the vehicle speed S as a parameter. At this time, step 420a in FIG. 11 is replaced with steps 701 and 702 in FIG. 12 (b). In step 701, the wind pressure signal Wp control signals from equal to or less than the predetermined value K ₃ proceeds to 420b when older than T _R seconds to stop the rear wheel control. still,
The control time T _R is more controlled when calculated from the two parameters of the vehicle speed S and the peak value Wpp at which the wind pressure signal becomes maximum in the period from when the wind pressure signal Wp becomes Wp ≧ K ₁ to Wp ≦ K _3. Accuracy is improved.

In the above embodiment, the yaw rate data _n-1 before rear wheel control is set as _B in step 410g of FIG. 10, and the current yaw rate data _n-1 is set in step 420a of FIG.
_{When n} became equal to _B , the steering control of the rear wheels was stopped and ended, but steps 410g, 410h, 420a were carried out in FIG. 13 (a),
The steps 800, 801, and 802 shown in (b) may be replaced. In step 800, an integrated value Σy obtained by integrating the yaw rate signal y _i
i , that is, the rotation angle of the vehicle due to the disturbance is obtained, and step 801
Then, the command value θ of the rear wheel steering control is set to the vehicle speed S and the integrated value Σy _i
A more accurate control value is calculated. Step 80
At 2, the integrated value Σy _i = 0, that is, it is determined whether or not the attitude of the vehicle is in the same direction as before the disturbance is applied, and the control ends. As a result, it is possible to accurately correct the vehicle traveling direction before the disturbance.

Although the rear wheel steering correction is performed in the above-described embodiment, the front wheel may be corrected similarly.

As described above, according to the present case, the steady running state of the vehicle is detected, and the steering correction is performed so as to automatically cancel the disturbance acting on the vehicle in this state. At times, it is possible to drive the vehicle in a straight line even against crosswinds. Further, since the change in the posture of the vehicle and the change in the trajectory can be suppressed to the minimum, the running of the vehicle can be stably maintained. On the other hand, during unsteady driving in which the driver is willing to operate, the disturbance is not corrected, so that steering and riding feeling can be obtained without a feeling of strangeness.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a basic structure of an embodiment of the present invention, FIG. 2 is a block circuit diagram of an electric control device (17), and FIGS. 3 to 6 are flow charts showing a flow of a microcomputer. 3, FIG. 3 is a main routine thereof, FIG. 4 is an interrupt routine, FIG. 5 is a vehicle speed interrupt routine, and FIG. 6 is a direction switching valve interrupt routine. FIG. 7 is a flow chart showing the details of the steady running state determination step 302 of FIG.
FIG. 8 is an explanatory diagram for explaining step 303 in FIG.
FIG. 9 shows the yaw rate signal averaging process step 40 in FIG.
3 is an explanatory diagram for explaining 3, FIG. 10 is a flowchart showing details of the disturbance determination step 410 in FIG. 4, and FIG.
FIG. 12 is a flowchart showing details of the solenoid valve control step 420, FIG. 12 is a partial flowchart showing another embodiment, FIG.
FIG. 13 is a partial flowchart showing another embodiment. 1 …… accelerator sensor, 2 …… brake switch, 3 …… front wheel steering angle, 4 …… vehicle speed sensor, 5 …… yaw rate sensor, 6…
… Wind pressure sensor, 17 …… Electric control device, 23 …… Auto drive switch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuichi Imani 1-1, Showa-cho, Kariya city, Aichi Prefecture Nihon Denso Co., Ltd. (72) Inventor Shinji Hiraiwa 1-1-chome, Showa town, Kariya city, Aichi prefecture Co., Ltd. (56) Reference JP-A-59-134060 (JP, A) JP-A-61-244669 (JP, A) JP-A-62-88666 (JP, A)

Claims (8)

[Claims] 1. A steady running state determination means for determining whether or not the vehicle is in a steady running state where the vehicle speed is substantially constant, and a steady running state determining means, and detecting a disturbance acting on the vehicle to respond to the disturbance. Disturbance detecting means for generating the disturbance signal, correction value calculating means for obtaining a traveling correction value to correct the vehicle traveling state based on the disturbance signal, and the vehicle in the steady traveling state in response to the steady traveling signal. When it is determined that the wheels are steered according to the travel correction value, and when it is determined that the vehicle is not in a steady traveling state, wheel steering means for prohibiting steering of the wheels by the travel correction value is provided. A travel correction device for a vehicle characterized by the above. 2. The traveling correction device for a vehicle according to claim 1, wherein the steady traveling state determination means generates the steady traveling signal in response to an operation of an auto drive operation switch. . 3. The steady running condition determining means includes vehicle speed change determining means for generating the steady running signal when the vehicle is running at a constant speed with a change in vehicle speed less than a predetermined value. A travel correction device for a vehicle according to the item. 4. The steady running state determination means inputs an accelerator change signal from an accelerator change means for detecting a change in accelerator opening and a brake signal from a brake detection means for detect a brake operation, and receives the accelerator signal. 3. The vehicle according to claim 1, wherein the steady running signal is generated when the change signal is less than a predetermined value and the brake signal indicates that the brake is not being operated. Driving correction device. 5. The steady running state determination means permits the generation of the steady running signal when the vehicle speed signal from the vehicle speed sensor for detecting the vehicle speed is equal to or higher than a predetermined speed. The travel correction device for a vehicle according to item 1 or 2. 6. The vehicle travel correction device according to claim 1, wherein the disturbance detection means is wind force detection means for detecting wind force acting on the vehicle. 7. The vehicle travel correction device according to claim 1, wherein the disturbance detection means is a yaw rate detection means for detecting a yaw rate applied to the vehicle. 8. The vehicle travel correcting device according to claim 1, wherein the wheel steering means is a rear wheel steering means for steering the rear wheels of the vehicle.