JP3949743B2 - Inter-vehicle distance control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inter-vehicle distance control device that uses a radar device that keeps the vehicle speed constant and tracks the front vehicle and keeps the inter-vehicle distance constant in order to prevent a rear-end collision with the front vehicle, and is particularly smooth and responsive. The present invention relates to an inter-vehicle distance control device capable of good speed control.
[0002]
[Prior art]
As a current vehicle control, many cruise devices that keep the vehicle speed constant are applied to automobiles. This cruise device is provided with a set switch for storing the current vehicle speed, an accelerator switch for accelerating and decelerating, and a coast switch for the driver, so that the throttle actuator can be opened and closed according to the driver's switch operation. I have to. Furthermore, this cruise device may be provided with an inter-vehicle distance control function for maintaining a constant inter-vehicle distance from the preceding vehicle, and these are collectively put into practical use as an inter-vehicle distance control device.
[0003]
This inter-vehicle distance control device radiates millimeter waves toward the front of the vehicle, calculates inter-vehicle distance D and relative speed (V2 -V1) from the reflected wave, and is necessary based on the inter-vehicle distance from the preceding vehicle Accordingly, the throttle actuator is opened and closed to accelerate and decelerate.
FIG. 5 is a diagram for explaining acceleration and deceleration characteristics of a conventional inter-vehicle distance control device. This will be described below with reference to the drawings.
[0004]
In the inter-vehicle distance control device, an optimal inter-vehicle distance D corresponding to the host vehicle speed is stored in advance as an inter-vehicle distance map in the memory. When the driver does not detect the front vehicle and the driver operates the set switch, the traveling speed at this time (referred to as the storage speed Vm) is input, and overshoot and undershoot are performed based on the storage speed Vm. In consideration of the above, a target speed VT for actually adjusting the speed of the vehicle is calculated, and constant speed running is performed. After that, when approaching a preceding vehicle that is slower than the host vehicle, readjustment is performed such that, for example, the actual speed that has been running at a constant speed has been reduced so that the inter-vehicle distance D does not fall within a predetermined value. In this case, the target speed VT is not changed, and is adjusted based on the actual speed.
[0005]
As a result, the host vehicle travels while maintaining a constant distance D at the same speed as the preceding vehicle. If the driver gives an instruction to accelerate while driving at the actually measured speed V1 while maintaining the predetermined inter-vehicle distance D (turns on the accelerator switch), the inter-vehicle distance control device increases the target speed VT in accordance with the instruction. At this time, the actual measured speed V1 is lower than the target speed VT, but the inter-vehicle distance control device instructs to increase the current speed so that the actual speed matches the changed target speed VT ( Instruct the cruise ECU to open the throttle actuator).
[0006]
On the other hand, if the driver gives an instruction to decelerate while driving at the actually measured speed V1 while maintaining the predetermined inter-vehicle distance D (turns on the coast switch), the inter-vehicle distance control device sets the target speed VT for smooth deceleration. Reduce gradually. At this time, control is performed to reduce the current speed so that the actual speed matches the reduced target speed VT. In this way, smooth deceleration is achieved. The target speed VT is set to change as the accelerator switch and coast switch are kept pressed.
[0007]
[Problems to be solved by the invention]
In the above-described method, when the driver operates the accelerator switch to accelerate during the inter-vehicle distance control, the inter-vehicle distance D decreases because the own vehicle speed V1 increases unless the speed V2 of the front vehicle changes. As a result, it is necessary to decelerate. That is, when the driver tries to accelerate, the inter-vehicle distance control device performs an opposite operation to decelerate.
[0008]
On the other hand, when the driver requests deceleration, the driver feels that the speed of the vehicle is actually high or the distance between the vehicles is short, and it is necessary to appropriately decelerate. When the driver operates the coast switch to reduce the speed while driving at the actually measured speed V1 while maintaining the predetermined distance D, the distance control device stores the storage speed Vm stored in the memory for smooth deceleration. Based on this, the target speed VT with the speed lowered step by step is calculated. The target speed VT, which is decreased stepwise, is compared with the actually measured speed V1, and when the target speed VT becomes lower than the actually measured speed V1, the vehicle is actually decelerated. However, since priority is given to maintaining the inter-vehicle distance D during inter-vehicle distance control, the speed V1 of the host vehicle is affected by the speed V2 of the preceding vehicle, and the target speed VT, the stored speed Vm, and the actually measured speed V1 are not necessarily equal. I'm not necessarily doing it. If there is a speed divergence between the target speed VT and the actual speed V1 (usually, the actual speed V1 is lower or the same as the target speed VT), the target speed VT will be applied even if the driver gives a command for deceleration. Therefore, while the target speed VT is lowered to the actual speed V1, the vehicle is not actually decelerated and a time lag occurs. As a result, there is a problem that even if the storage speed Vm and the target speed VT are lowered, it takes time until the speed of the vehicle is actually lowered. The cause of these problems is that cruise control and inter-vehicle distance control are not well suited as software.
[0009]
An object of the present invention is to provide an inter-vehicle distance control device that does not accept an acceleration instruction during inter-vehicle distance control, and can smoothly and quickly decelerate when there is a deceleration instruction.
[0010]
[Means for Solving the Problems]
In order to solve such a problem, the present invention increases or decreases a target speed set in advance according to the operation of a switch for acceleration by a driver or the operation of a switch for deceleration. Alternatively, the current speed of the own vehicle is adjusted so that the speed of the own vehicle coincides with the target speed that has been decelerated, and the constant-speed traveling control is performed, and the inter-vehicle distance from the preceding vehicle becomes a preset inter-vehicle distance. In the inter-vehicle distance control device comprising inter-vehicle distance control means for re-adjusting the speed of the host vehicle and controlling the inter-vehicle distance as described above,
When the switch for decelerating is operated and the inter-vehicle distance control is not being performed, a reduction process is performed in which the current target vehicle speed is reduced by a predetermined amount, and the target speed is gradually reduced as a new target vehicle speed. ,
On the other hand, when it is determined that the switch for decelerating is operated and the inter-vehicle distance control is in progress, the target speed when the speed is set higher than the current speed of the host vehicle, After performing the process of setting to match the current speed of the host vehicle, the target speed set to match the current speed of the host vehicle is reduced by a predetermined amount to a new target A reduction process for reducing the target vehicle speed stepwise as a speed is performed, and constant speed running control is performed so that the current speed of the host vehicle becomes the new target speed.
[0015]
Further, the set speed set in advance is increased or decreased in response to the driver's acceleration request or deceleration request, and the current speed of the host vehicle is set so that the speed of the host vehicle matches the increased or decreased set speed. Adjust to control constant speed travel, and readjust the speed of the vehicle so that the relationship between the speed of the vehicle and the distance between the vehicle and the vehicle is based on the stored map. In the inter-vehicle distance control device, comprising the inter-vehicle distance control means for controlling the inter-vehicle distance and the storage means for always storing the map, the inter-vehicle distance control means sends the deceleration request during the inter-vehicle distance control. When it is detected, the vehicle has means for changing the inter-vehicle distance corresponding to the current speed of the vehicle on the map in a large direction and storing it in the map, and after the ignition switch of the vehicle is turned off, when it is turned on Serial and is characterized in that on the basis of said stored modified mapped in the storage unit is made by adjusting the speed of the vehicle.
[0016]
Reference numeral 1 denotes a millimeter wave radar device using the Doppler effect installed in front of the own vehicle, which detects a reflected wave of a beam irradiated forward and outputs it to the subsequent stage. A vehicle speed sensor 2 measures the speed V1 of the host vehicle. Reference numeral 3 denotes an accelerator switch for instructing acceleration. 4 is a coast switch for instructing deceleration. Reference numeral 5 denotes a set switch for instructing the speed to be input to the control unit (microcomputer 61), and the vehicle speed when the switch is operated is input. 6 is a microcomputer that performs signal processing of the reflected wave detected by the radar device 1 and measures the inter-vehicle distance D and relative speed (V2 -V1) to the front vehicle, and recognizes the front vehicle based on this and performs inter-vehicle distance control. 61, a millimeter wave radar signal processing ECU constituted by memories such as a ROM 62 and a RAM 63 in which various data are stored. A cruise ECU 7 controls the speed by adjusting the throttle actuator 8 according to an instruction from the millimeter wave radar signal processing ECU 6. As a result, a certain distance between the vehicle and the front vehicle is maintained. Reference numeral 9 denotes a brake, and the inter-vehicle distance control traveling is canceled by stepping on the brake. Although the millimeter wave radar signal processing ECU 6 and the cruise ECU 7 are configured as separate ECUs, the present invention is not limited to this, and may be configured as a single ECU in which these are combined.
[0017]
First, the acceleration instruction will be described with reference to the flowchart showing the processing contents of the microcomputer 61 in FIG. In step S1, it is determined whether or not the accelerator switch 3 is on. If the accelerator switch 3 is on, the process proceeds to step S2. If not, the process proceeds to step S6. That is, it is determined whether or not the accelerator switch 3 is operated by the driver.
[0018]
In step S2, it is determined whether or not the inter-vehicle distance control is being performed based on the relative distance from the preceding vehicle. That is, control is not performed if the relative distance is sufficiently greater than or equal to a predetermined value, and control is performed if the relative distance is less than or equal to the predetermined value. If the inter-vehicle distance control is being performed, the process proceeds to step S6. If the inter-vehicle distance control is not being performed, the process proceeds to step S3. In other words, since the inter-vehicle distance is maintained in an optimal state during inter-vehicle distance control, acceleration according to the acceleration request inevitably shortens the inter-vehicle distance, and it is necessary to decelerate immediately. In such a driving operation, the crew member is in an unnatural state of repeating acceleration and deceleration, so the acceleration request is ignored. As a result, acceleration control is not performed, and the vehicle travels substantially as it is.
[0019]
In step S3, the target speed VT is set to VT +1, and the process proceeds to step S4. That is, in order to perform acceleration control, the target speed VT is increased stepwise in accordance with a predetermined program. In step S4, the opening / closing angle θ of the throttle actuator 8 is set to k (VT−V1), and the process proceeds to step S5. That is, the microcomputer 61 determines the opening / closing angle θ of the throttle actuator 8 according to the difference between the target speed VT and the current vehicle speed V1 in order to accelerate. In step S5, the cruise ECU 7 is instructed according to the determined opening / closing angle θ of the throttle actuator 8, and the process is terminated. That is, the cruise ECU 7 is instructed to open and close (usually in the opening direction because of acceleration) according to the determined opening / closing angle θ of the throttle actuator 8, and the process is ended. The throttle actuator 8 is opened and the vehicle is accelerated.
[0020]
In step S6, normal inter-vehicle distance control is performed and the process ends. That is, if acceleration is performed according to the acceleration request during inter-vehicle distance control, the distance from the preceding vehicle is inevitably shortened, and deceleration is required immediately. If acceleration and deceleration are repeated in this way, the passenger feels uncomfortable, so the vehicle travels by normal inter-vehicle control ignoring the acceleration request.
Next, the case of a deceleration instruction will be described with reference to the flowchart showing the processing contents of the microcomputer 61 in FIG. In step S11, it is determined whether or not the coast switch 4 is on. If it is on, the process proceeds to step S12, and if it is not on, the process proceeds to step S16. That is, it is determined whether or not the coast switch 4 has been operated by the driver.
[0021]
In step S12, it is determined whether the inter-vehicle distance control is being performed. If the inter-vehicle distance control is being performed, the process proceeds to step S13, and if the inter-vehicle distance control is not being performed, the process proceeds to step S14. That is, if the inter-vehicle distance control is not being performed, deceleration in the normal deceleration mode is performed according to the deceleration request.
In step S13, the actually measured speed V1 is substituted for the storage speed Vm and the target speed VT, and the process proceeds to step S14. That is, while the inter-vehicle distance control is being performed, the inter-vehicle distance D is maintained in an optimal state, but the speed of the own vehicle (actually measured speed V1) in that case is determined depending on the speed V2 of the preceding vehicle, and the preceding vehicle is slow. In this case, the storage speed Vm stored in the RAM 63 or the like is slower than the target speed VT, and a speed divergence occurs between them. Therefore, the vehicle is not decelerated during a period in which the actually measured speed V1 is lower than the target speed VT decelerated according to a predetermined program (see the solid line in FIG. 5). In order to decelerate the vehicle immediately when a deceleration request is made, the stored speed Vm and the target speed VT are made to coincide with the actually measured speed V1 as shown by the broken line in FIG. The target speed VT becomes lower than the actually measured speed V1, and deceleration can be started. That is, in this example, the speed in the inter-vehicle distance control is preferentially used.
[0022]
In step S14, the target speed VT is set to VT-1, and the process proceeds to step S15. That is, in order to perform the deceleration control, the target speed VT is decreased stepwise according to a predetermined program. In step S15, the opening / closing angle θ of the throttle actuator 8 is set to k (VT−V1), and the process proceeds to step S16. That is, the microcomputer 61 determines the opening / closing angle θ of the throttle actuator 8 according to the difference between the target speed VT and the current vehicle speed V1 in order to decelerate. According to the determined opening / closing angle θ of the throttle actuator 8, the throttle actuator 8 is opened / closed (normally in the closing direction because of deceleration), and the vehicle is decelerated.
[0023]
In step S16, normal inter-vehicle distance control is performed and the process ends. That is, control that satisfies a predetermined inter-vehicle distance and a set speed is performed.
As described above, in this embodiment, it is possible to provide an inter-vehicle distance control device that does not accept an acceleration instruction during inter-vehicle distance control and can smoothly and immediately decelerate with a deceleration instruction.
[0024]
FIG. 4 is a diagram for explaining an example of changing the inter-vehicle distance of the inter-vehicle distance control device of the second embodiment of the present invention. This will be described below with reference to the drawings.
In the first embodiment, when the deceleration is instructed, the storage speed Vm and the target speed VT are changed so as to coincide with the actually measured speed V1, and the deceleration is performed based on the speed. Rather than processing to directly change the speed Vm and the target speed VT, the relationship between the vehicle speed V stored in advance in the RAM 63 or the like and the optimum inter-vehicle distance Df (referred to as an inter-vehicle distance map, which is displayed in bold lines in FIG. 4) Is intended to achieve deceleration processing.
[0025]
That is, instead of lowering the storage speed Vm and the target speed VT to achieve deceleration, in FIG. 4, the inter-vehicle distance map initially composed of a thick line is used to show the optimal inter-vehicle distance Df1 at the current vehicle speed V1 in the direction of the arrow (the inter-vehicle distance is In the direction of lengthening, it is actually moved to the nearest map point). By changing the inter-vehicle distance in the direction of increasing the inter-vehicle distance map, the current inter-vehicle distance Df1 is shorter than the changed inter-vehicle distance Df2, so that the vehicle is immediately decelerated to maintain the changed inter-vehicle distance Df2. . In other words, deceleration control is not performed based on the target vehicle speed for cruise control, but deceleration control is performed using actual vehicle speed change in inter-vehicle distance control.
[0026]
The inter-vehicle distance map is changed by the driver operating the coast switch 4 so that the inter-vehicle distance becomes longer. When the driver determines that the desired speed is reached, the driver releases the coast switch 4. The inter-vehicle distance corresponding to the speed of the vehicle at that time is input as the inter-vehicle distance Df2 in the map. Incidentally, as shown in FIG. 4, in the intermediate point of the speeds in which the current vehicle speed is stored in the inter-vehicle distance map, the point closest to the current vehicle speed V1 (the inter-vehicle distance corresponding to the current vehicle speed) is corrected. When the inter-vehicle distance map is used, the inter-vehicle distance corresponding to the current vehicle speed is obtained by interpolation of the two points closest to the current vehicle speed.
[0027]
This changed inter-vehicle distance map is used in that state until the ignition switch is turned off. When the ignition switch is turned off, the driver may change, so that the original state (original inter-vehicle distance map) is restored. Also, if the probability that the same driver will get on is high, the changed inter-vehicle distance map is stored in a memory such as the backup RAM 63 or E ² PROM to which power is always supplied, and is changed even after the ignition switch is turned off. It is also possible to use an inter-vehicle distance map.
[0028]
As described above, in this embodiment, it is possible to provide an inter-vehicle distance control device that can immediately decelerate so that the driver's desired inter-vehicle distance is obtained.
[0029]
【The invention's effect】
As described above, according to the present invention, an acceleration instruction is not accepted during inter-vehicle distance control, and the deceleration instruction can smoothly and quickly decelerate, and further, the inter-vehicle distance can be learned according to the driver. A control device can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a system configuration of an inter-vehicle distance control device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the processing contents of a microcomputer in the case of an acceleration instruction of an inter-vehicle distance control device according to an embodiment of the present invention.
FIG. 3 is a flowchart for explaining the processing contents of the microcomputer in the case of a deceleration instruction of the inter-vehicle distance control device according to the embodiment of the present invention.
FIG. 4 is a diagram showing an example of changing the inter-vehicle distance of the inter-vehicle distance control device according to the second embodiment of the present invention.
FIG. 5 is a diagram for explaining acceleration and deceleration characteristics by a conventional inter-vehicle distance control device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Radar apparatus 5 ... Set switch 2 ... Vehicle speed sensor 6 ... Millimeter wave radar signal processing ECU
3 ... Accelerator switch 7 ... Cruise ECU
4 ... Coast switch 8 ... Throttle actuator

Claims (1)

The target speed set in advance is increased or decreased according to the operation of the switch for accelerating by the driver or the operation of the switch for decelerating, and the vehicle speed matches the increased or decelerated target speed. The current speed of the host vehicle is adjusted to control the constant speed travel, and the speed of the host vehicle is readjusted so that the inter-vehicle distance with the preceding vehicle becomes a preset inter-vehicle distance. In the inter-vehicle distance control device comprising inter-vehicle distance control means for controlling the inter-vehicle distance,
When the switch for decelerating is operated and the inter-vehicle distance control is not being performed, a reduction process is performed in which the current target vehicle speed is reduced by a predetermined amount, and the target speed is gradually reduced as a new target vehicle speed. ,
On the other hand, when it is determined that the switch for decelerating is operated and the inter-vehicle distance control is in progress, the target speed when the speed is set higher than the current speed of the host vehicle, After performing the process of setting to match the current speed of the host vehicle, the target speed set to match the current speed of the host vehicle is reduced by a predetermined amount to a new target An inter-vehicle distance control device that performs a reduction process for gradually reducing a target vehicle speed as a speed, and controls constant-speed traveling so that the current speed of the host vehicle becomes the new target speed.

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