JPH03217340A - Travel control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a travel control device that allows a vehicle to follow while maintaining an optimal distance from a preceding vehicle. [Prior Art] A travel control device that measures the distance between the vehicle and the preceding vehicle and operates an automatic speed control device to maintain the distance between the vehicles at a constant value is disclosed, for example, in Japanese Patent Publication No. 57-22771. This was conceived as an application of conventional constant-speed cruise control, and instead of the speed signal of constant-speed cruise control, the opening degree of the throttle valve is determined based on the inter-vehicle distance and relative speed, and the engine output is determined. The structure is designed to maintain a constant distance between the vehicle and the vehicle in front.

[Problem to be solved by the invention]

The above-mentioned driving control device can follow the vehicle as desired by controlling the following distance if the vehicle in front and the own vehicle are traveling at a nearly constant speed, so it is important to pay close attention to the distance between vehicles under driving conditions such as highways. This can be expected to have the effect of reducing driver fatigue by eliminating the need to pay. However, in terms of following driving including when the vehicle starts, it is difficult to perform following driving by controlling the inter-vehicle distance because the starting means and the driving conditions of the preceding vehicle and the own vehicle at the time of starting are not taken into consideration.

For example, considering the start operation, the vehicle is stopped before starting, but the vehicle must be stopped so that it does not move unexpectedly due to disturbances such as the slope of the road. Furthermore, if the preceding vehicle starts, the driver must start his own vehicle after detecting this. This means that there is a considerable time delay (dead time) before the own vehicle starts driving, and this is not expected since conventional inter-vehicle distance control methods do not take into account such wasted time elements at all. Street following is not possible. When a vehicle starts, it is considered to be a driving state in which the acceleration is particularly large, and the conventional following distance system IIl is
In the follow-up driving method, the distance between vehicles widens when the vehicle starts due to the above-mentioned dead time factor, and in the worst case, it becomes difficult to measure the distance between vehicles and the follow-up travel has to be interrupted.

In addition, if the gain of the inter-vehicle distance control is increased to cover the above-mentioned wasted time when starting and to enable following from the start, hunting will occur in the inter-vehicle distance and speed during normal follow-up driving, making the driver uncomfortable. could not be raised.

Therefore, under driving conditions such as on general roads where the vehicle frequently starts, accelerates, decelerates, and stops, it is necessary to frequently set following distance control after the vehicle has started, and driver fatigue is never alleviated. Additionally, if the settings were forgotten, the driver's intentions and the vehicle's behavior would not match, which could be dangerous. This invention was made to solve these problems, and it is possible to start the own vehicle from a stationary state when the preceding vehicle starts, and thereafter perform follow-up driving by controlling the following distance. The purpose of the present invention is to provide a driving control device that can decelerate and stop in accordance with the deceleration and stop of a preceding vehicle, and can follow the vehicle even on general roads where starting and stopping are repeated, thereby reducing driver fatigue. [
Means for Solving the Problems] A driving control device according to the present invention includes a following distance measuring device that measures the distance between the vehicle in front and the preceding vehicle, a vehicle speed sensor that measures the traveling speed of the own vehicle, and a throttle that controls the engine output. A valve opening control device, a brake control device that controls the brakes, and the throttle valve opening control device and brake control so that the following distance to the preceding vehicle becomes a predetermined value in accordance with the output signal of the following distance measuring device. and a driving means for driving the device, which distinguishes the driving mode into a starting mode in which the own vehicle reaches a predetermined train of cars from a stopped state and a starting mode based on the output signal of the vehicle speed sensor, and other modes. The control is performed by changing at least the control gain of the throttle valve opening degree control device or the brake control device according to the above.

[For production]

In the driving control device according to the present invention, in a following driving state, a computer calculates a target inter-vehicle distance in that driving state, and calculates the following distance between the own vehicle and the preceding vehicle based on the inter-vehicle distance measured by the inter-vehicle distance measuring device and the time change of this inter-vehicle distance. The driving force required to maintain the target inter-vehicle distance is calculated from the relative speed of the vehicle and the speed of the own vehicle using a predetermined calculation formula, converted to engine output, and further converted to a target throttle valve opening.
A throttle valve opening control device can be controlled.

〔Example〕

An embodiment of this invention will be explained below with reference to the drawings. 1st
The figure shows a block diagram of a travel control device according to the present invention,
In the figure, 2 is a distance measuring device with a near-infrared LED.
The LED is driven in pulses to illuminate the vehicle in front, and the reflected light from the vehicle in front is imaged on an optical position detector located a predetermined distance from the LED, and the distance between vehicles is measured using triangulation based on the detected position. ．． The LED drive pulse period is log+s, and measurement is performed every log+s, but in order to absorb measurement errors due to disturbances, the measured values are averaged and a measured value of the inter-vehicle distance is output every 50+ss. Reference numeral 1 denotes a computer unit, in addition to the inter-vehicle distance detection signal from the inter-vehicle distance detector 2, an engine rotation sensor 31 detects the rotation speed of the engine 3, and detects the rotation speed of the output shaft of the transmission 4 for speed control. The driver receives a signal from the vehicle speed sensor 41, and a signal from the follow-up command switch 7, which is used by the driver to set the follow-up driving mode. The transmission 4 is an automatic transmission having a fluid-coupled so-called torque converter, but it may also be a combination of a continuously variable transmission and a clutch. Reference numeral 43 denotes a shift lever drive device which, during follow-up operation, is controlled by commands from the computer unit 1 and moves the shift lever 42 to a target shift lever position.

5 is a throttle valve opening control device, and a throttle valve 51
and a motor 52 that opens and closes a throttle valve 51 and is controlled by the computer unit 1. Reference numeral 6 is a brake control device, which controls the brake hydraulic pressure using the negative pressure of the engine or the hydraulic pressure obtained by operating the hydraulic pump, and adjusts the deceleration of the vehicle according to commands from the computer UNISOTORI. This brake control device 6 is installed in parallel with the main brake system operated by the driver, and is configured so that the higher hydraulic pressure during operation is selected as the brake hydraulic pressure.

On the other hand, in the following running state, the computer unit 1
calculates the target inter-vehicle distance in that driving state, and calculates the above target inter-vehicle distance from the inter-vehicle distance measured by the inter-vehicle distance measurement device, the relative speed of the own vehicle and the preceding vehicle determined from the time change of this inter-vehicle distance, and the own vehicle's speed. The driving force required to maintain the distance is calculated using the formula below, and this is converted into engine output, which is converted into a target throttle valve opening to control the throttle valve opening control device 5. .

Driving force = KIX (target inter-vehicle distance - inter-vehicle distance) 10 K2 x relative speed ... ta + where Kl and K2 are proportional coefficients. The relative speed in the equation is given by the change in inter-vehicle distance over time. To convert driving force to engine output, it is sufficient to simply divide the driving force by the gear ratio of the transmission, but when using an automatic transmission with a torque converter, the power output of the torque converter is also converted to shaft rotation. It can be converted by dividing the ratio of numbers by the torque ratio as a parameter. Here, the input shaft rotation speed of the torque converter is the engine rotation speed, and the output shaft rotation speed is determined from the speed of the own vehicle. Since engine output is determined by engine speed and throttle valve opening, the target throttle valve opening can be calculated from data stored in the form of a map using engine speed and engine output as parameters. .

When the preceding vehicle decelerates and the target inter-vehicle distance cannot be maintained by reducing the engine output alone, that is, when the driving force calculated by the above formula +al becomes a negative value, the brake control device is activated to increase the brake pressure to the above value. The vehicle is controlled in proportion to the driving force to reduce speed and maintain the target inter-vehicle distance. Furthermore, if the vehicle in front comes to a stop, the engine output is minimized by closing the throttle valve, and the brakes are activated to ensure that the vehicle comes to a stop. The computer detects the start of the preceding vehicle based on changes in the measured distance between vehicles, and after confirming that the preceding vehicle has moved away by a predetermined distance, releases the brake and starts the own vehicle. The driving force at this time is calculated using the calculation formula (
For example, the target throttle valve opening is calculated using a computer using the following data (Shoniyama)), and the throttle valve opening control device is controlled to start the vehicle. Driving force = K10X (target inter-vehicle distance - inter-vehicle distance) + K20
X relative velocity...(b) Here KIO, K2
0 is a proportional coefficient, and the coefficients Kl and K2 of the above formula (al) have been changed so that it is larger than the calculation result of the above formula ial.

When the vehicle starts following again and the speed of the own vehicle exceeds the predetermined speed, the calculation formula for the driving force is changed to a normal formula (for example, formula (a)
). Next, the operation will be explained using the flowcharts shown in FIGS. 2 to 6.

First, the calculation process in the computer unit 1 is performed every time the distance between vehicles is measured, that is, every 5 (1+s). In FIG. It is configured to be able to update and store 10 measured values, and the CPU
(Central processing unit, not shown here) can read out past inter-vehicle distance measurements at any time.In the next step 101, the difference between the current inter-vehicle distance measurement value and the previous inter-vehicle distance measurement value is calculated. Since this difference is a change in the inter-vehicle distance during the calculation period of 5 oas, it is a value corresponding to the relative speed.Next, the state of the following command switch 7 is checked at 110, and if the following command switch 7 is off, the step 1
After executing the normal running control process in step 50, the process proceeds to step 200.

When the following command switch 7 is turned on in step 110, the process branches to step 120, and it is determined whether the own vehicle is stopped, that is, whether the speed of the own vehicle outputted by the vehicle speed sensor 41 is O. If the own vehicle is stopped, step 140
If the host vehicle is running, the process branches to step 130.

In step 140, the current inter-vehicle distance measurement value is compared with the inter-vehicle distance measurement value four times ago, that is, 200ms ago, and if the inter-vehicle distance has increased by 10 cm or more, it is determined that the preceding vehicle has started, and the process branches to step 170, which is the start process. If there is no change in the inter-vehicle distance, the process branches to a stop process in step 180, executes each process, and then proceeds to step 200. In step 130, it is determined whether the current driving mode is the start mode and the speed of the own vehicle is less than the set value 5-/h.
If the vehicle is in start mode and the speed is less than 5 km/h, execute step 170 start processing, otherwise proceed to step 1.
After executing the follow-up process 60, the process proceeds to step 200. Next, step 1500 normal driving mode will be explained with reference to the flow chart of FIG. 3. In step 151, the target opening of the throttle valve is set to a value proportional to the amount of depression of an accelerator pedal (not shown), and in step 152, a shift lever control command is issued. The shift lever drive unit W43 is set to be disconnected from the shift lever 42, allowing the driver to operate it freely. The target brake pressure is set to 0 using the stem 153, so that hydraulic pressure is applied to the brake only by the driver's brake operation. Therefore, in normal driving mode, it is completely different from a normal car (the driver sets control target values for the throttle valve, shift lever, and brakes so that he can operate the car). FIG. 4 is a flowchart of the follow-up process in step 160, in which the driving mode is set to follow-up mode in step 161, the shift lever control command is set to the drive range in step 162, and the target inter-vehicle distance and inter-vehicle distance are measured in step 163. The driving force is determined from the above-mentioned equation (a) from the value and the relative velocity determined in step 101. In step 164, the value of equation (al) is evaluated, and if the result of equation (a) is positive, the process branches to step 165 and the target brake is set to 0. In step 166, the driving force determined by equation fat is set to the gear ratio, The target engine output is determined by dividing by the torque converter torque ratio.Meanwhile, in step 164, the equation (al
When the evaluation result of . In step 169, step 16
6 or from the engine output and engine speed determined in step 16B, the throttle valve opening is measured in advance and read out by interpolation calculation from the throttle opening map stored in the form of a manop, and is set as the target throttle valve opening. FIG. 5 is a flowchart of the start process in step 170. In the start process, in step 171 the driving mode is set to start mode, in step 172 the shift lever control command is set to the drive range, and in step 173 the target inter-vehicle distance is set, From the measured inter-vehicle distance and the relative speed determined in step 101, the driving force is determined using the above 2...). In step 174, the value of ``Niyama'' is evaluated, and if the result of ``Niyama'' is positive, the process branches to step 175 and the target brake is set to O.
In step 176, the target engine output is determined by dividing the driving force determined by the formula (bl) by the gear ratio and the torque converter torque ratio.On the other hand, in step 174, if the evaluation result of the formula (bl) is negative, in step 177 Driving force (formula (b
)) is multiplied by a coefficient (K brko) to set the target brake pressure, and in step 178 the target engine output is set to O. In step 179, step 176
Alternatively, the throttle valve opening is measured in advance from the engine output and engine speed determined in step 178, and is read out by interpolation from the throttle valve opening map stored in the form of a map and set as the target throttle valve opening. FIG. 6 is a flowchart of the stop processing of the stethoscope 180, in which the driving mode is set to the stop mode in step 181, the shift lever control command is set to neutral in step 182, and the target brake pressure is set to the brake control device 6 in step 183. is set to the maximum controllable brake pressure, and in step 184, the target throttle valve opening is set to O (fully closed).

The steno valve 200 drives the motor 52 of the throttle valve opening control device 5 to adjust the throttle valve 51 so that the throttle valve opening is set in the previous process. In step 210, the calculated target brake pressure is commanded to the brake control device 6 to control the brake pressure.

The travel control device according to the present invention realizes following-driving to a preceding vehicle through the arithmetic processing described above, and is capable of following the preceding vehicle. The flow of processing when driving with repeated stops is that when the vehicle is stopped, it is stopped in the stop process in step 180, and when the preceding vehicle starts, it starts in the start process in step 170, and the acceleration at the time of start is calculated using the driving force Since the speed is set larger than normal, the speed increases quickly, and the vehicle in front can start disobeying the vehicle without losing distance from it. My car's speed is 5
km/h, the vehicle follows the vehicle in the follow-up process at step 160. During follow-up driving, the gain of the driving force calculation using formula (al) is smaller than when starting, so the following distance can be smoothly followed without hunting. When the preceding vehicle stops, the brakes are automatically applied during the follow-up process in step 170. When the vehicle stops, the shift lever also goes to the neutral position and the vehicle comes to a complete stop.When the vehicle in front starts again, the process from Steno Knob 170 onwards is repeated, so it is not possible to start and stop like on a general road. Even in repeated running conditions, omnidirectional driving is possible.Furthermore, even if the vehicle in front decelerates to a stop when the speed of the own vehicle is less than 5-/h in the start mode, the brakes are activated during the start process in step 170. The vehicle will stop and there will be no rear-end collision.

Furthermore, the coefficient of target brake pressure calculation in start mode (K
By setting brkO) to a larger value than the coefficient (K brk) during following driving, even if the preceding vehicle suddenly brakes immediately after starting, it is possible to brake with remaining force, and even in that case, the vehicle speed is The speed is as low as 1m/h, which increases safety without causing discomfort to the driver. In the above embodiment, formulas (a) and (bl) were used as the driving force calculation formula for inter-vehicle distance control, but other formulas may be used for calculation. The same effect as the above embodiment can be obtained by omitting a series of calculations such as the opening degree and simply calculating the throttle valve opening degree directly from the inter-vehicle distance, relative speed, and speed of the own vehicle.

〔Effect of the invention〕

As explained above, according to the present invention, the following distance system 1T
When following the vehicle in front using J, we changed the coefficients of the engine output calculation formula for inter-vehicle distance control during normal following and when starting, so that a greater acceleration can be obtained when starting, so the following can be done immediately after starting. In addition, when decelerating, not only is engine output reduced, but also brake control is applied to decelerate, making it easier to start. This enables follow-up driving on general roads where the vehicle frequently starts and stops.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a travel control device according to an embodiment of the present invention, and FIGS. 2 to 6 are flowcharts for explaining the operation of the present invention. ■...Computer unit, 2...Distance measuring device, 3...Engine, 4...Automatic transmission, 5...
- Throttle valve opening control device, 6... Brake control device, 31... Engine rotation sensor, 4l... Vehicle speed sensor, 51... Throttle valve, 52... Motor.

Claims (1)

[Claims] A vehicle distance measuring device that measures the distance between the vehicle in front of the vehicle, a vehicle speed sensor that measures the traveling speed of the own vehicle, a throttle valve opening control device that controls the engine output, and a brake control device that controls the brakes. and a driving means for driving the throttle valve opening control device and the brake control device so that the distance between the vehicles in front and the preceding vehicle becomes a predetermined value according to the output signal of the vehicle speed sensor, and The driving mode is divided into a starting mode in which the vehicle reaches a predetermined speed from a stopped state, and other modes, and the control gain of at least the throttle valve opening control device or the brake control device is adjusted depending on the driving mode. A travel control device characterized in that the travel control device performs control by changing the.