JP5109915B2 - Driving support device - Google Patents

Description

  The present invention relates to a travel support device, and more particularly to a travel support device that is suitable for use in assisting a vehicle when traveling on an uphill road or a downhill road.

Conventionally, so-called auto-cruise control for causing a vehicle to travel at a constant vehicle speed is known as vehicle travel support control. In auto cruise control, an auto cruise control method for reducing fuel consumption is known (for example, Patent Document 1). In this auto-cruise control method, when there is an uphill road on the road on which the vehicle is traveling, the current target vehicle speed and a vehicle speed that is slower than the current target vehicle speed by a constant vehicle speed (for example, a vehicle speed that is slower by about 10 km / h). The minimum fuel consumption vehicle speed is set as the target vehicle speed. By setting the target vehicle speed in this way, fuel efficiency is improved when traveling on an uphill road.
JP-A-8-295154

  However, in the auto cruise control method described in Patent Document 1, acceleration / deceleration is performed with the minimum fuel consumption vehicle speed as the target vehicle speed. For this reason, the energy loss accompanying acceleration / deceleration occurs, and there is a problem that waste is generated in the fuel consumption correspondingly.

  Accordingly, an object of the present invention is to provide a travel support device that can improve fuel efficiency when assisting travel at a constant vehicle speed.

The vehicle travel support apparatus according to the present invention that solves the above problems supports vehicle travel at a constant target vehicle speed, and when traveling on a slope, sets a predetermined allowable range for the target vehicle speed and performs support related to vehicle speed. In the driving support device, the vehicle speed control for assisting by allowing the vehicle speed change in the opposite direction to the vehicle speed change caused by running on the slope at the position before the slope, and the slope information acquisition means for acquiring the slope information ahead of the road. And a vehicle speed control means calculates a current target vehicle speed, which is a current target vehicle speed in the vehicle, based on the target vehicle speed and the slope information acquired by the slope information acquisition means, and calculates the calculated current target vehicle speed. It is characterized by providing support according to the situation.

  In the travel support device according to the present invention, the vehicle travels at a constant target vehicle speed, and when traveling on the slope, a predetermined allowable range is set for the target vehicle speed and the vehicle speed is supported. At the position, assistance is provided by allowing a change in the vehicle speed in the opposite direction to the change in the vehicle speed due to running on the ramp. Specifically, when the slope is an uphill road, “change in vehicle speed due to running on the slope” is decelerated. Therefore, “allowing a change in vehicle speed opposite to that due to running on the slope” Will be suppressed or acceleration will be allowed. On the other hand, when the slope is a downhill road, the “change in vehicle speed due to running on the slope” is accelerated. Therefore, “allowing a change in vehicle speed opposite to the change in vehicle speed due to running on the slope” suppresses acceleration. Or allow deceleration. In this way, by providing support while allowing a change in the vehicle speed in the opposite direction to the change in vehicle speed due to running on the slope, energy loss associated with acceleration / deceleration during running on the slope can be suppressed. As a result, when supporting traveling at a constant vehicle speed, it is possible to improve fuel efficiency associated with suppression of energy loss.

The vehicle speed control means calculates a safe speed range for the vehicle to travel safely based on the slope information, and when the current target vehicle speed is out of the safe speed range, the safe speed range is substituted for the current target vehicle speed. It can be set as the aspect which performs the support according to the inside speed .

  In this way, the vehicle speed change in the direction that offsets the change in the vehicle speed due to the slope is compensated by providing support at the front position of the slope according to the vehicle speed before running on the slope where the vehicle speed after running on the slope becomes the target vehicle speed. Can be tolerated. Therefore, the amount of acceleration / deceleration required during and after running on the ramp can be reduced, and fuel efficiency can be improved accordingly. Here, according to the vehicle speed before running on the ramp, as an aspect of performing the support in the section before the ramp, when the ramp is an uphill road, an increase in the vehicle speed with respect to the target vehicle speed is allowed. Or a decrease in the vehicle speed with respect to the target vehicle speed. On the other hand, when the slope is a downhill road, a decrease in the vehicle speed with respect to the target vehicle speed is permitted, or an increase in the vehicle speed with respect to the target vehicle speed is suppressed.

  Further, when the slope is an uphill road, it is possible to provide an aspect of performing support for suppressing deceleration at a position before the slope.

  Thus, when the slope is an uphill road, by suppressing deceleration at a position before the slope, the vehicle enters the uphill road with the vehicle speed exceeding the target vehicle speed. As a result, a decrease in vehicle speed due to traveling on an uphill road can be compensated for, and fuel consumption can be improved along with suppression of energy loss.

  Further, when the slope is a downhill road, it is possible to provide a mode in which assistance for suppressing acceleration is performed at a position before the slope.

  As described above, when the inclined road is a downhill road, by suppressing acceleration at a position before the inclined road, the vehicle enters the downhill road in a state where the vehicle speed is lower than the target vehicle speed. As a result, an increase in vehicle speed due to traveling on a downhill road can be compensated for, and fuel consumption can be improved along with suppression of energy loss.

  According to the travel support device of the present invention, it is possible to improve fuel efficiency when assisting travel at a constant vehicle speed.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. For the convenience of illustration, the dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a block diagram of a driving support apparatus according to an embodiment of the present invention. As shown in FIG. 1, the travel support apparatus according to the present embodiment includes a travel control ECU (Electronic Control Unit) 1. A navigation ECU 2 is connected to the travel control ECU 1, and a GPS (Global Positioning System) device 3 is connected to the navigation ECU 2. A drive control ECU 4 and a brake control ECU 5 are connected to the travel control ECU 1. The travel control ECU 1 further includes a travel condition acquisition unit 11, a potential energy calculation unit 12, a target current speed calculation unit 13, a speed comparison unit 14, and a vehicle speed control unit 15.

  The travel control ECU 1 is an electronic control unit including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, and the like, and comprehensively controls the steering assist device.

  The navigation ECU 2 is a device for providing the driver with the current position of the vehicle and route information to the destination. The navigation ECU 2 stores map information related to the road on which the vehicle travels. The map information related to the road in this map information includes road gradient, curvature, safe speed of the road, and the like.

  The GPS device 3 performs wireless communication with GPS satellites arranged outside the vehicle, and detects the position of the vehicle on which the GPS device 3 is mounted based on the result of this wireless communication. The GPS device 3 transmits a vehicle position detection value related to the detected vehicle position to the navigation ECU 2.

  Further, the navigation ECU 2 roughly detects the traveling position of the vehicle based on the vehicle position detection value transmitted from the GPS device 3, and detects the vehicle speed sensor, the gyroscope, the yaw rate sensor, and the like around the approximate position detected based on the vehicle position detection value. The correct current position and traveling direction of the vehicle are detected while matching the map information. The navigation ECU 2 transmits road information including road gradient information and curvature information and travel position information regarding the current position and travel direction of the vehicle to the travel condition acquisition unit 11 in the travel control ECU 1. Further, the navigation ECU 2 transmits road information to the potential energy calculation unit 12.

  The travel condition acquisition unit 11 in the travel control ECU 1 acquires planned travel route information of a planned travel route that is a road on which the vehicle is scheduled to travel based on the road information and the travel position information transmitted from the navigation ECU 2. Here, the planned travel route information includes road altitude, slope, track length, curve curvature, safe speed information such as banks, and the like. The traveling condition acquisition unit 11 outputs the acquired forward gradient information and planned traveling route information to the potential energy calculation unit 12.

  In addition, the travel condition acquisition unit 11 is based on the acquired forward gradient information, planned travel route information, and the like, and a safe speed range (Vmax, Vmin) for the vehicle to travel safely and an acceleration / deceleration amount when traveling on the slope. Is calculated. The traveling condition acquisition unit 11 outputs the calculated safe speed range to the vehicle speed control unit 15 and outputs the calculated acceleration / deceleration amount to the target current speed calculation unit 13.

  The potential energy calculation unit 12 calculates the potential energy that the vehicle acquires or loses after traveling on the slope, based on the road information output from the navigation ECU 2. The potential energy calculation unit 12 outputs the calculated potential energy to the target current speed calculation unit 13.

  The target current speed calculation unit 13 calculates the target current vehicle speed based on the acceleration / deceleration amount output from the travel condition acquisition unit 11. The target current vehicle speed is a current speed for achieving the target vehicle speed after traveling on the forward travel path. The target current speed calculation unit 13 outputs the calculated target current vehicle speed to the speed comparison unit 14.

  The speed comparison unit 14 compares the target vehicle speed with the target current vehicle speed, and outputs the comparison result to the vehicle speed control unit 15. The vehicle speed control unit 15 performs vehicle speed control based on the comparison result output from the speed comparison unit 14 and the safe speed range output from the travel condition acquisition unit 11.

In performing the vehicle speed control, the vehicle speed control unit 15 does not strictly determine the target vehicle speed (target current vehicle speed), but performs the control while allowing the speed error α within a certain allowable range from the target vehicle speed. For example, when the forward traveling road is an uphill road, an allowable range is set with a speed error α ₊ as the target vehicle speed. Further, when the forward traveling road is a downhill road, an allowable range is set with a speed error α _{− for the} target vehicle speed.

These speed errors α are determined based on the gradient of the traveling road ahead, the safe speed, and the like. Specifically, when the target vehicle speed is 90 km / h, the speed error α ₊ is 10 km / h and the speed error α ₋ is −10 km / h. The vehicle speed control unit 15 calculates the acceleration / deceleration of the vehicle according to the target vehicle speed thus determined, and transmits the acceleration / deceleration amount based on the calculated acceleration / deceleration to the drive control ECU 4 and the brake control ECU 5. At this time, acceleration / deceleration is suppressed when the forward traveling road is a slope, and at this time, acceleration / deceleration is suppressed by control gain or output adjustment.

  The drive control ECU 4 controls drive devices such as an engine, a motor, and a hybrid computer based on the acceleration / deceleration amount transmitted from the vehicle speed control unit 15 in the travel control ECU 1. The brake control ECU 5 performs deceleration control by a braking device such as a brake based on the acceleration / deceleration amount transmitted from the vehicle speed control unit 15 in the travel control ECU 1.

  Next, a processing procedure in the travel support apparatus according to the present embodiment will be described. FIG. 2 is a flowchart showing a processing procedure in the travel support apparatus according to the present embodiment.

  As shown in FIG. 2, in the travel support device according to the present embodiment, first, the travel condition acquisition unit 11 acquires the planned travel route information of the vehicle (S1). Here, based on the map information and the travel position information transmitted from the navigation ECU 2, the gradient information of the planned travel route, the altitude of the road, the track length, the safe speed, and the like are acquired as the planned travel route information. At this time, if the front of the planned travel route is an uphill road or a downhill road, an altitude difference δh between the current position and the summit is obtained. Furthermore, when the safe speed is acquired, the lower limit speed Vmin and the upper limit speed Vmax in the safe speed range are further acquired as planned travel route information. In addition, the vehicle weight m is acquired as vehicle information.

  When the planned travel route information is acquired, the potential energy calculation unit 12 calculates the potential energy Ep that the vehicle acquires or loses when traveling on the forward travel route (S2). Here, the potential energy Ep acquired or lost when traveling on an uphill road or a downhill road on the planned travel route is calculated based on the altitude difference δh obtained from the road gradient.

  When the potential energy Ep is calculated in this way, the target current speed calculation unit 13 sets the vehicle speed Vl that is the vehicle speed when traveling on the uphill road or the downhill road, and the speed of the slope for preventing energy loss. The target vehicle speed Vt and the target current vehicle speed Ve, which is the current vehicle speed when the vehicle has completed traveling on the slope, are the target vehicle speed Vt (S3).

  Here, it is assumed that the vehicle speed is allowed to reach the target vehicle speed Vt after the completion of the hill road travel, and the target current vehicle speed Ve is calculated assuming that the hill road vehicle speed Vl becomes the target vehicle speed Vt after the hill road travel is completed. In this case, the target current vehicle speed Ve can be obtained by the following equation (1) from the relationship between the potential energy Ep, the slope traveling vehicle speed Vl obtained from the planned traveling route, and the target vehicle speed Vt. The following formula (1) can be obtained by modifying the following formulas (2) to (4).

Ve = (Vt ² +2 gδh) ^1/2 (1)
Ep / m = 2gδh = Ve ² −Vl ² (2)
Vl = (Ve ² −2gδh) ^1/2 (3)
Vl = Vt (4)

  When the target current vehicle speed Ve is thus obtained, the speed comparison unit 14 obtains the difference between the target current vehicle speed Ve and the target vehicle speed Vt, and determines whether the target current vehicle speed Ve and the target vehicle speed Vt are large or small (S4). As a result, when it is determined that the target current vehicle speed Ve and the target vehicle speed Vt are the same (Ve−Vt = 0), the road ahead of the vehicle is flat. In this case, the vehicle speed control unit 15, normal control is performed (S9). In normal control, the vehicle is accelerated or decelerated to bring the current vehicle speed closer to the target vehicle speed.

  Further, when it is determined that the target current vehicle speed Ve is larger than the target vehicle speed Vt (Ve> Vt), the current vehicle speed Vnow, which is the current vehicle speed, is set to the target current vehicle speed Ve and the upper limit speed Vmax of the safe speed range. In other words, it is determined whether or not the current vehicle speed Vnow is less than or equal to the target current vehicle speed Ve within the safe speed range (S5).

  As a result, when the current vehicle speed Vnow is equal to or lower than the target current vehicle speed Ve within the safe speed range, the vehicle speed control unit 15 performs deceleration suppression control that suppresses deceleration (S6). The deceleration suppression control is performed by suppressing the output of the brake control or suppressing the deceleration side of the control gain. When suppressing the output of the brake control, the brake control can be omitted or the output of the brake control can be reduced. Further, when suppressing the deceleration side of the control gain, the control gain can be set to 0 or the control gain can be reduced. Thus, by performing deceleration suppression control, energy loss due to deceleration control can be reduced.

On the other hand, when the current vehicle speed Vnow is not less than or equal to the target current vehicle speed Ve within the safe speed range, it is not necessary to secure energy by the control deviation. For this reason, normal control is performed (S9). However, the corrected target current vehicle speed Ve + β ₊ can be obtained by correcting the target current vehicle speed Ve to some extent, assuming a deviation on the (−) side. In this way, it is possible to tolerate speeds that are somewhat higher than expected.

In addition, when the current vehicle speed Vnow is larger than the upper limit speed Vmax of the safe speed range and is out of the safe speed range, the speed is within the upper limit speed Vmax so as to maintain the upper limit of the safe travel range. Normal control is performed (S9). However, in consideration of the control performance to the upper limit speed Vmax, the corrected upper limit speed Vmax−γ ₊ obtained by correcting the upper limit speed can be set as a safe speed range up to a slower speed considering the control error.

  Further, when it is determined that the target current vehicle speed Ve is smaller than the target vehicle speed Vt (Ve <Vt), the current vehicle speed Vnow, which is the current vehicle speed, is set to the target current vehicle speed Ve and the lower limit speed Vmin of the safe speed range. In other words, it is determined whether or not the current vehicle speed Vnow is equal to or higher than the target current vehicle speed Ve within the safe speed range (S7).

  As a result, when the current vehicle speed Vnow is equal to or higher than the target current vehicle speed Ve within the safe speed range, the vehicle speed control unit 15 performs acceleration suppression control for suppressing acceleration (S8). The acceleration suppression control is performed by suppressing the output of drive control or suppressing the acceleration side of the control gain. When suppressing the output of the drive control, the drive control can be omitted or the output of the drive control can be reduced. Further, when suppressing the acceleration side of the control gain, the control gain can be set to 0, or the control gain can be reduced. Thus, by performing acceleration suppression control, energy loss due to acceleration control can be reduced.

On the other hand, when the current vehicle speed Vnow is not equal to or higher than the target current vehicle speed Ve within the safe speed range, it is not necessary to secure energy by the control deviation. For this reason, normal control is performed (S9). However, (+) assuming side deviations, target correction was currently corrected vehicle speed Ve was somewhat smaller target current vehicle speed Ve + beta _- and can also be. In this way, it is possible to tolerate speeds that are somewhat higher than expected.

When the current vehicle speed Vnow is smaller than the lower limit speed Vmin of the safe speed range and is out of the safe speed range, the speed is within the lower limit speed Vmin so as to maintain the lower limit of the safe travel range. Normal control is performed (S9). However, in consideration of the control performance to the lower limit speed Vmin, the corrected lower limit speed Vmin + γ ₊ can be set as a safe speed range up to a slower speed considering the control error.

  As described above, the vehicle speed control unit 15 allows the speed error α of the speed control to a certain extent based on the target current vehicle speed Ve calculated by the target current speed calculation unit 13, and conditions of the outside world such as a gradient in the traveling direction. Thus, the control error tolerance method and range, the control method, and the control gain are changed. For this reason, since acceleration / deceleration for recovering the control deviation can be suppressed, energy loss due to accelerator operation or brake operation can be reduced. As a result, it is possible to improve the fuel efficiency when assisting the traveling at the target vehicle speed Vt.

  For example, when the vehicle travels on the travel path schematically shown in FIG. 3, the target vehicle speed is set to 90 km / h. The traveling road shown in FIG. 3 includes a first flat road RL1, a second flat road RL2, and a third flat road RL3 that are horizontal, and an uphill road between the first flat road RL1 and the second flat road RL2. It is assumed that RU exists and a downhill road RD exists between the second flat road RL2 and the third flat road RL3. Further, the first boundary point A between the first flat road RL1 and the uphill road RU, the second boundary point B between the uphill road RU and the second flat road RL2, the second flat road RL2 and the downhill road RD, Is the third boundary point C, and the boundary between the downhill road RD and the third flat road RL3 is the fourth boundary point D. Further, it is assumed that the target vehicle speed Vt is 90 km / h and the speed error α is 10 km / h.

  Here, when the vehicle M is traveling on the first flat road RL1 or the uphill road RU, the forward road is an uphill road. In this case, the target vehicle speed Vt on the second flat road RL2 is 90 km / h. For example, a vehicle traveling on the first flat road RL1 or the uphill road RD is traveling at a speed of 90 km / h to 100 km / h. To do.

  When the vehicle M is traveling on the first flat road RL1 at a speed in this range, the control deviation can be used to acquire the speed by suppressing the brake applied to the vehicle M. Further, when the vehicle M is traveling on the uphill road RU at a speed in this range, the control deviation can be used to acquire the speed by making an accelerator request that allows the vehicle M to decrease in speed. Thus, energy loss due to brake operation can be reduced. As a result, it is possible to improve the fuel efficiency when assisting the traveling at the target vehicle speed Vt.

  Further, when the vehicle M is traveling on the second flat road RL2 or the downhill road RD, the forward travel road is a downhill road. In this case, the target vehicle speed Vt on the third flat road RL3 is 90 km / h. For example, the vehicle M traveling on the second flat road RL2 or the downhill road RD is traveling at a speed of 80 km / h to 90 km / h. Suppose.

  Further, when the vehicle M is traveling on the second flat road RL2 or the downhill road RD at a speed in this range, the control deviation is used for speed acquisition by suppressing the accelerator control applied to the vehicle M. Can do. Further, when the vehicle M is traveling on the downhill road RD at a speed in this range, the control deviation can be used to acquire the speed by making a brake request for allowing the vehicle M to accelerate. Thus, energy loss due to the accelerator operation can be reduced. As a result, it is possible to improve the fuel efficiency when assisting the traveling at the target vehicle speed Vt.

  Then, the vehicle speed control unit 15 performs vehicle speed control according to the determined acceleration / deceleration amount or the like (S10). In performing this vehicle speed control, the vehicle speed control unit 15 transmits the acceleration / deceleration amount to the drive control ECU 4 and the brake control ECU 5.

  Next, FIG. 4 shows an image of changes in the travel path and the vehicle speed when the travel control according to the present embodiment is performed. In FIG. 4, when the current road condition is a flat road and the front road is an uphill road, the control gain is adjusted to increase the speed, and the speed change is increasing. On the uphill road that follows, the earned speed is consumed and the control gain is adjusted to gain speed.

  In addition, when the current road condition is a flat road and the traveling road ahead is a downhill road, the control gain is adjusted so as to reduce the speed, and the speed change is low. On the subsequent downhill road, the reduced speed is restored and the control gain is adjusted to reduce the speed. By performing such speed control, it is possible to reduce energy loss due to brake operation or accelerator operation. As a result, it is possible to improve the fuel efficiency when assisting the traveling at the target vehicle speed Vt.

  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 embodiment, the deceleration control or the acceleration control is suppressed according to the target current vehicle speed before the hill. However, the deceleration control or the acceleration control is suppressed regardless of the target current vehicle speed. Can do. In the above embodiment, the upper limit speed and the lower limit speed of the safe speed range are determined based on the forward gradient information, the scheduled travel route information, and the like. However, preset upper limit speeds and lower limit speeds may be used.

It is a block block diagram of the driving assistance device which concerns on embodiment of this invention. It is a flowchart which shows the process sequence in the driving assistance device which concerns on this embodiment. It is a schematic diagram of the travel path along which a vehicle travels. It is a graph which shows the image of the change of a travel path and vehicle speed at the time of performing travel control concerning this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Travel control ECU, 2 ... Navigation ECU, 3 ... GPS apparatus, 4 ... Drive control ECU, 5 ... Brake control ECU, 11 ... Travel condition acquisition part, 12 ... Position energy calculation part, 13 ... Target present speed calculation part, DESCRIPTION OF SYMBOLS 14 ... Speed comparison part, 15 ... Vehicle speed control part, M ... Vehicle, RL1 ... First flat road, RL2 ... Second flat road, RL3 ... Third flat road, RD ... Downhill road, RU ... Uphill road.

Claims (4)

In a driving support device that supports driving of a vehicle at a constant target vehicle speed and sets a predetermined allowable range for the target vehicle speed when driving on a slope, and supports the vehicle speed,
Ramp information acquisition means for acquiring ramp information in front of the traveling road;
Vehicle speed control means for allowing and supporting the vehicle speed change in the opposite direction to the vehicle speed change due to the running on the slope at a position before the slope ;
With
The vehicle speed control means calculates a current target vehicle speed that is a current target vehicle speed in the vehicle based on the target vehicle speed and the slope information acquired by the slope information acquisition means, and according to the calculated current target vehicle speed. driving assistance apparatus characterized by providing support. The vehicle speed control means calculates a safe speed range for the vehicle to travel safely based on the slope information,
The travel support apparatus according to claim 1, wherein when the current target vehicle speed is out of the safe speed range, support according to a speed within the safe speed range is performed instead of the current target vehicle speed.   The driving support device according to claim 1 or 2, wherein when the slope is an uphill road, the driving assistance device performs support for suppressing deceleration at a position before the slope.   The travel support device according to claim 1 or 2, wherein when the slope is a downhill road, support for suppressing acceleration is performed at a position before the slope.

Images