JP2013044558A - Grade estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately estimate a grade at sudden grade change, beginning of grade change, or during acceleration or deceleration of a vehicle.SOLUTION: A grade estimation device 11 calculates weight grade resistance acting on a vehicle 1 on the basis of a driving state of the vehicle 1, estimates a grade during travel of the vehicle 1 on the basis of the calculated weight grade resistance, and defines the estimated grade as an internal grade calculated value. The grade estimation device 11 acquires a grade during travel of the vehicle from a navigation system 28, and defines the acquired grade as a navigation grade. Then, the grade estimation device 11 corrects the internal grade calculated value on the basis of difference between the internal grade calculated value and the navigation grade.

Description

  The present invention relates to a technique for estimating a gradient.

  The shift control device for an automatic transmission described in Patent Document 1 has a function of estimating a gradient. The shift control device changes the shift pattern in accordance with the estimated gradient and realizes a shift suitable for the gradient.

JP 7-167273 A

  The gradient can be estimated based on the weight gradient resistance obtained by calculation from the driving state of the vehicle (vehicle speed, engine speed, etc.).

  However, the conventional gradient estimation has a problem that the estimation accuracy is low at the time of sudden gradient change, at the beginning of gradient change, or during acceleration / deceleration. This is because a filtering process is included in the estimation process, so the estimated gradient is delayed with respect to the actual gradient, and the calculation error of the driving force used for calculating the weight gradient resistance increases during acceleration / deceleration. is there.

  The present invention has been made in view of such technical problems, and it is an object of the present invention to make it possible to estimate the gradient with high accuracy even when the gradient suddenly changes, during the initial gradient change, or during acceleration / deceleration. .

  According to an aspect of the present invention, the gradient estimation device calculates a weight gradient resistance acting on the vehicle based on the driving state of the vehicle, estimates a gradient during which the vehicle is traveling based on the calculated weight gradient resistance, Is the internal gradient calculation value. Further, the gradient estimation device acquires a gradient in which the vehicle is traveling from the navigation system, and uses this as the navigation gradient. The gradient estimation device calculates the corrected gradient by correcting the internal gradient calculation value based on the difference between the internal gradient calculation value and the navigation gradient.

  According to the above aspect, even after a sudden gradient change in which the deviation between the actual gradient and the internal gradient calculation value is large, the initial gradient change, or during acceleration / deceleration, the corrected gradient is more dependent on the actual gradient than the internal gradient calculation value. It can approach quickly and can estimate the gradient with high accuracy.

1 is a schematic configuration diagram of a vehicle including a gradient estimation device according to an embodiment of the present invention. It is the figure which showed a mode that an error produced in an internal gradient calculation value. It is the flowchart which showed the content of the internal gradient calculation value correction process. It is the flowchart which showed the content of the internal gradient calculation value correction process. It is the figure which showed the relationship between a navigation gradient and the presence or absence of gradient correction. It is the figure which showed the relationship between the absolute value of a navigation gradient time change rate, and the presence or absence of gradient correction. It is the figure which showed the mode of determination whether it is during acceleration / deceleration. It is the figure which showed the correction | amendment permission area | region during acceleration / deceleration. It is a table for setting a gradient correction amount. It is a table for setting a target correction amount. It is the figure which showed the relationship between the absolute value of the time change rate of an internal gradient calculation value, and the presence or absence of gradient correction. It is the figure which showed the correction | amendment permission area | region during non-acceleration / deceleration. It is a time chart which showed a mode that an internal gradient calculation value was correct | amended.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a vehicle including a gradient estimation device according to an embodiment of the present invention.

  The vehicle 1 includes an engine 2 as a power source, and the power of the engine 2 is transmitted to the left and right rear wheels 7 via the automatic transmission 3, the propeller shaft 4, the differential unit 5, and the drive shaft 6.

  The transmission controller 10 is a controller that controls the gear position of the automatic transmission 3. The transmission controller 10 includes a vehicle speed sensor 21, an intake air amount sensor 22, an intake air temperature sensor 23, an engine rotational speed sensor 24, an accelerator opening sensor 25, a brake switch 26, a transmission output rotational speed sensor 27, a navigation system 28, and the like. Signal is input. Based on the input signals from these sensors and devices, the transmission controller 10 sets a target shift stage with reference to a shift map (not shown), and sets the automatic transmission 3 so that the set shift stage is realized. Control.

  The transmission controller 10 includes a gradient estimation device 11 inside, and based on the gradient estimated by the gradient estimation device 11, the shift line of the shift map is changed to improve drivability on the uphill road and the downhill road. Let For example, if it is an uphill road, the shift line is changed so that the low-side shift stage is frequently used.

  The gradient estimation device 11 calculates the weight gradient resistance R0 by subtracting the acceleration resistance R1, the air resistance R2, and the rolling resistance R3 from the driving force F of the engine 2 and filtering the values.

  The driving force F of the engine 2 calculates the torque of the engine 2 by referring to a predetermined map based on the rotational speed of the engine 2 and the intake air amount, and the torque ratio of the torque converter of the automatic transmission 3 and the automatic transmission It is calculated based on the gear ratio of the machine 3, the final reduction ratio, the transmission efficiency of the automatic transmission 3, and the tire diameters of the left and right rear wheels 7 as drive wheels.

  The acceleration resistance R1 is calculated based on the weight and acceleration of the vehicle 1. The acceleration of the vehicle 1 is calculated based on the temporal change rate of the transmission output rotation speed, the tire diameter, and the final reduction ratio. Hereinafter, the vehicle acceleration calculated in this way is referred to as “internally calculated acceleration”.

  The air resistance R2 is calculated based on the vehicle speed, the front projected area of the vehicle 1, the air density, and the air resistance coefficient.

  The rolling resistance R3 is calculated based on the weight of the vehicle 1 and the rolling resistance coefficient.

  With reference to a table that defines the relationship between the weight gradient resistance and the gradient, in which the weight gradient resistance R0 is calculated, the gradient of the road surface on which the vehicle 1 is currently traveling is calculated. The gradient calculated in this way is hereinafter referred to as “internal gradient calculation value”.

  However, the internal gradient calculation value calculated in this way has a problem that the estimation accuracy is low when the gradient suddenly changes, during the initial gradient change, or during acceleration / deceleration. This is because, as described above, the process of estimating the gradient includes a filtering process, and during acceleration / deceleration, the calculation accuracy of the driving force of the engine 2 used for calculating the weight gradient resistance is low. is there.

  FIG. 2 is a diagram schematically showing a change in the internal gradient calculation value when the actual gradient changes. Since a plurality of filter processes are included in the calculation process of the internal gradient calculation value, the internal gradient calculation value changes with a delay with respect to the change of the actual gradient in this way.

  On the other hand, the navigation system 28 includes map data, and altitude information can be obtained from the current position information and the map data. Therefore, it is conceivable to calculate the gradient based on this information (hereinafter calculated in this way). The map data stored in the navigation system 28 includes a memory capacity (when the map data is stored in the internal memory) and a communication speed (map data is externally transmitted by wireless communication). Since there are errors due to data being thinned out due to the relationship (when obtained) and surveying errors, there is a problem in using the navigation gradient as it is for control.

  Therefore, the gradient estimation device 11 corrects the internal gradient calculation value based on the navigation gradient so as to obtain a gradient closer to the actual gradient.

  FIG. 3A and FIG. 3B are flowcharts showing the content of processing (internal gradient calculation value correction processing) for correcting the internal gradient calculation value and obtaining a corrected gradient closer to the actual gradient. Executed by. Hereinafter, the content of the internal gradient calculation value correction process will be described with reference to this.

First, the gradient estimation device 11 sets a counter k to 0. The counter k is a counter that counts the number of times a later-described gradient correction amount i _k is added to the internal gradient calculation value.

  Next, the gradient estimation device 11 determines whether the navigation gradient is larger than the uphill determination threshold LimGRDup and whether the navigation gradient is smaller than the downhill determination threshold LimGRDdwn (S2). As described above, the navigation gradient is a gradient calculated based on altitude information from the navigation system 28, and takes a positive value on an uphill road, zero on a flat road, and a negative value on a descending road.

  If the navigation gradient is larger than the uphill determination threshold LimGRDup, or if the navigation gradient is smaller than the downhill determination threshold LimGRDdwn, that is, if the internal gradient calculation value needs to be corrected, the processing is Proceed to S3.

  On the other hand, when the navigation gradient is between the uphill determination threshold LimGRDup and the downhill determination threshold LimGRDdwn, that is, when driving on a flat road or the gradient is slight and the internal gradient calculation value does not need to be corrected In step S14 (FIG. 3B), the internal gradient calculation value is not corrected.

  The reason for not correcting the internal gradient calculation value when there is a small amount of flat road or slope is that the error of the internal gradient calculation value is small and there is little need for correction, and the fluctuation of the corrected gradient due to frequent corrections It is for preventing.

  As a result, as shown in FIG. 4, only when the navigation gradient is larger than the uphill determination threshold LimGRDup or when the navigation gradient is smaller than the downhill determination threshold LimGRDdwn, the gradient estimation device 11 performs the internal gradient calculation. Correct the value.

  In S3, the gradient estimation device 11 determines whether the absolute value of the time change rate of the navigation gradient is smaller than the upper limit change rate ΔGRD, and if the absolute value of the navigation gradient time change rate is smaller than the upper limit change rate ΔGRD, The process proceeds to S4.

  On the other hand, when the absolute value of the time change rate of the navigation gradient is larger than the upper limit change rate ΔGRD, the change of the navigation gradient is extreme, and there is a high possibility that the navigation gradient includes an error. Proceeding to (FIG. 3B), the internal gradient calculation value is not corrected.

  For example, when the navigation gradient is extremely changed, if the vehicle position cannot be accurately measured by GPS and the vehicle position on the map is deviated from the actual vehicle position, then the vehicle position is accurate. If the vehicle position on the map is instantaneously moved to the actual vehicle position and the altitude information from the navigation system 28 changes abruptly, or the data is related to the memory capacity of the navigation system 28 and the communication speed. Is thinned out, and the navigation gradient changes more rapidly than the actual gradient.

  FIG. 5 shows how the navigation gradient changes with time. The gradient estimation device 11 corrects the internal gradient calculation value at time t1 when the time change rate of the navigation gradient becomes smaller than the upper limit change rate ΔGRD, but the time change rate of the navigation gradient is larger than the upper limit change rate ΔGRD. The internal gradient calculation value is not corrected at time t2 when it is determined that the navigation gradient error is likely to be large.

  In S4, the gradient estimation device 11 determines whether the absolute value of the internal calculation acceleration is larger than the acceleration / deceleration determination threshold value α. In this determination, a change in driving force is large during vehicle acceleration / deceleration, and an error in the internal gradient calculation value is larger than that during non-acceleration / deceleration. Is done to make the difference.

  FIG. 6 shows a state of determination as to whether or not acceleration / deceleration is being performed. When the absolute value of the internally calculated acceleration is larger than the acceleration / deceleration determination threshold value α, it is determined that acceleration / deceleration is being performed, and when it is smaller, non-acceleration is determined. It is determined that the vehicle is decelerating (steady running or slow acceleration / deceleration).

  If it is determined that the absolute value of the internal calculated acceleration is greater than the acceleration / deceleration determination threshold value α, the process proceeds to S5, and the absolute value of the internal calculated acceleration is greater than the acceleration / deceleration determination threshold value α. If it is determined that the acceleration / deceleration is small, the process proceeds to S8.

  In S5, the gradient estimation device 11 compares the difference between the navigation gradient and the calculated internal gradient with the upper limit difference value ErrGrdLimupA and the lower limit difference value ErrGrdLimdwnA, and the difference is between the upper limit difference value ErrGrdLimupA and the lower limit difference value ErrGrdLimdwnA. That is, it is determined whether the difference is in the correction permission area shown in FIG. 7. If the difference is in the correction permission area, the process proceeds to S6.

  If the difference is not within the correction permission area, the process proceeds to S14 (FIG. 3B) so that the internal gradient calculation value is not corrected. This is because the possibility that the error included in the navigation gradient is large is high when the difference is not within the correction permission region, so that the correction of the internal gradient calculation value is avoided in such a situation. Because.

In S6, the gradient estimation device 11 refers to the table shown in FIG. 8, acquires the acceleration / deceleration correction amount VIGRDA based on the difference between the navigation gradient and the internal gradient calculation value, and uses this as the gradient correction amount i _k. Set. The acceleration / deceleration correction amount VIGRDA increases as the absolute value of the difference between the navigation gradient and the calculated internal gradient increases, but the amount of change with respect to the amount of change in the difference decreases. As the value increases, the acceleration / deceleration correction amount VIGRDA takes a constant value. That is, an upper limit and a lower limit are set for the acceleration / deceleration correction amount VIGRDA.

As the absolute value of the difference is larger, the gradient correction amount i _k is increased so that the internal gradient calculation value quickly approaches the actual gradient, while the corrected gradient is used by the sudden change of the corrected gradient. This is to prevent adverse effects on control (for example, shift control).

  In S7, the gradient estimation device 11 refers to the table shown in FIG. 9, acquires the acceleration / deceleration target correction amount TGRDA based on the difference between the navigation gradient and the corrected gradient, and sets this as the target correction amount TGRD. To do. When the process of S7 is executed for the first time, there is no corrected gradient value, so the internal gradient calculation value is used as the corrected gradient.

  The acceleration / deceleration target correction amount TGRDA increases as the absolute value of the difference between the navigation gradient and the corrected gradient increases, but the amount of change relative to the change amount of the difference decreases, and the absolute value of the difference is greater than a certain value. As the value increases, the acceleration / deceleration target correction amount TGRDA takes a constant value. That is, an upper limit and a lower limit are set for the acceleration / deceleration target correction amount TGRDA.

This is because larger correction is performed as the absolute value of the difference is larger. As described later, the total S of the gradient correction amount i _k which is summed with the internal slope calculated value reaches the target correction amount TGRD, gradually reducing the value to be added to the internal gradient calculated value from the target correction amount TGRD In this case, the corrected gradient converges to the internal gradient calculation value without overshooting the actual gradient.

  On the other hand, in S8, where the internal calculation acceleration is smaller than the acceleration / deceleration determination threshold value α, the gradient estimation device 11 determines that the absolute value of the time change rate of the internal gradient calculation value before the filter processing is lower than the lower limit change rate ΔGRDin. If the absolute value of the time change rate of the internal gradient calculation value before the filter process is larger than the lower limit change rate ΔGRDin, the process proceeds to S9.

  On the other hand, if it is smaller than the lower limit change rate ΔGRDin, the process proceeds to S14 (FIG. 3B) so that the internal gradient calculation value is not corrected. This is the same as the process of S2, and correction of the internal gradient calculation value is performed only in a situation where the correction of the internal gradient calculation value is necessary, and the fluctuation of the corrected gradient due to frequent correction is prevented. It is to do.

  FIG. 10 shows how the correction of the internal gradient calculation value is permitted / prohibited by the process of S8. As shown in this figure, when the absolute value of the time change rate of the internal gradient calculation value before the filter processing is smaller than the lower limit change rate ΔGRDin, the correction of the internal gradient calculation value is prohibited.

  Note that the internal gradient calculation value before the filter processing is used instead of after the filter processing, because the value after the filter processing is delayed with respect to the actual gradient, so that it is used to determine the gradient at that time. Is not appropriate, and if it is not accelerating / decelerating, the calculation error of the calculated driving force is small, and the error of the internal gradient calculation value is also small. That's why.

  When the absolute value of the time change rate of the internal gradient calculation value before the filter process is larger than the upper limit change rate ΔGRDin, the process proceeds to S9.

  In S9, the gradient estimation device 11 compares the difference between the navigation gradient and the calculated internal gradient with the upper limit difference value ErrGrdLimupB and the lower limit difference value ErrGrdLimdwnB, and the difference is between the upper limit difference value ErrGrdLimupB and the lower limit difference value ErrGrdLimdwnB. That is, it is determined whether or not the difference is in the correction permission area shown in FIG. 11. If the difference is in the correction permission area, the process proceeds to S10.

  The upper limit difference value ErrGrdLimupB is larger than the upper limit difference value ErrGrdLimupA used during acceleration / deceleration, and the lower limit difference value ErrGrdLimdwnB is smaller than the lower limit difference value ErrGrdLimdwnA used during acceleration / deceleration. That is, the correction permission area is larger during non-acceleration / deceleration than during acceleration / deceleration.

  This is because during non-acceleration / deceleration, both the navigation information and the internal gradient calculation value are highly accurate and can be corrected over a wider range.

  If the difference is not within the correction permission area, the process proceeds to S14 (FIG. 3B) so that the internal gradient calculation value is not corrected. This is because the possibility that the error included in the navigation gradient is large is high when the difference is not within the correction permission region, so that the correction of the internal gradient calculation value is avoided in such a situation. Because.

In S10, the gradient estimation device 11 refers to the table shown in FIG. 8, acquires the non-acceleration / deceleration correction amount VIGRDB based on the difference between the navigation gradient and the internal gradient calculation value, and uses this as the gradient correction amount i _k. Set as. Non-acceleration / deceleration correction amount VIGRDB increases as the absolute value of the difference between the navigation gradient and the calculated internal gradient increases, but the amount of change with respect to the amount of change in the difference decreases, and the difference has a certain absolute value. If it becomes larger than this, the non-acceleration / deceleration correction amount VIGRDB takes a constant value. That is, an upper limit and a lower limit are set in the non-acceleration / deceleration correction amount VIGRDB.

As the absolute value of the difference is larger, the gradient correction amount i _k is increased so that the internal gradient calculation value quickly approaches the actual gradient, while the corrected gradient is used by the sudden change of the corrected gradient. This is to prevent adverse effects on control (for example, shift control).

The tendency of the non-acceleration / deceleration correction amount VIGRDB is the same as the acceleration / deceleration correction amount VIGRDA during acceleration / deceleration, but during non-acceleration / deceleration, the accuracy of both the navigation gradient and internal gradient calculation values is high, so the gradient correction amount If the difference between the navigation gradient and the internal gradient calculation value is the same so that i _k becomes a larger value, the non-acceleration / deceleration correction amount VIGRDB is set to a value larger than the acceleration / deceleration correction amount VIGRDA.

  In S11, the gradient estimation device 11 refers to the table shown in FIG. 9, acquires the non-acceleration / deceleration target correction amount TGRDB based on the difference between the navigation gradient and the corrected gradient, and uses this as the target correction amount TGRD. Set. When the process of S11 is executed for the first time, since there is no corrected gradient value, the internal gradient calculation value is used as the corrected gradient.

  The non-acceleration / deceleration target correction amount TGRDB increases as the absolute value of the difference between the navigation gradient and the corrected gradient increases, but the amount of change with respect to the change amount of the difference decreases, and the absolute value of the difference has a certain value. The target correction amount TGRDB during non-acceleration / deceleration takes a constant value. That is, an upper limit and a lower limit are set for the non-acceleration / deceleration target correction amount TGRDB.

This is because larger correction is performed as the absolute value of the difference is larger. As described later, a total S of the gradient correction amount i _k which is summed with the internal slope calculated value reaches the target correction amount TGRD, gradually reducing the value to be added to the internal gradient calculated value from the target correction amount TGRD In this case, the corrected gradient converges to the internal gradient calculation value without overshooting the actual gradient.

  The non-acceleration / deceleration target correction amount TGRDB has the same tendency as the acceleration / deceleration target correction amount TGRDA during acceleration / deceleration, but during non-acceleration / deceleration, both the navigation gradient and internal gradient calculation values are highly accurate. If the difference between the navigation gradient and the correction gradient is the same so that the correction amount TGRA becomes a larger value, the non-acceleration / deceleration target correction amount TGRDB is set to a value larger than the acceleration / deceleration target correction amount TGRDA. .

When the gradient correction amount i _k is set in S6 or S10 and the target correction amount TGRD is set in S7 or S8, the gradient estimation device 11 updates the total S (initial value is 0) of the gradient correction amount i _k , The corrected gradient is calculated by adding the total S to the internal gradient calculation value (S12). Then, the gradient estimation device 11 adds 1 to the counter k (S14).

  Thereafter, the procedure returns to S2, the processes of S2 to S13 are executed again, and the corrected gradient is updated.

Thereafter, when the absolute value of the sum S of the gradient correction amount i _k which is summed with the internal slope calculated value reaches the absolute value of the target correction amount TGRD, the process proceeds from S13 to S14 (FIG. 3B) (S13).

  In S14, the gradient estimation device 11 determines whether the absolute value of the corrected gradient is larger than the absolute value of the internal gradient calculation value. If the absolute value of the corrected gradient is greater than the absolute value of the internal gradient calculation value, the value to be added to the corrected gradient is corrected until the absolute value of the corrected gradient is no greater than the absolute value of the internal gradient calculation value. The process of decreasing the amount TGRD by a predetermined value DecGRD (S15 to S18) is repeated.

  As a result, the corrected gradient is gradually brought closer to the internal gradient calculation value, finally the corrected gradient is matched with the internal gradient calculation value, and the correction process of the internal gradient calculation value is completed.

  Then, the effect by correcting the said internal gradient calculation value is demonstrated.

  FIG. 12 is a time chart showing how the internal gradient calculation value is corrected by the above processing.

As shown in this figure, the internal gradient calculation value changes with a delay with respect to the actual gradient due to the filtering process, and the corrected gradient is calculated based on the difference between the navigation gradient and the internal gradient calculation value. The correction amount i _k is repeatedly added to the internal gradient calculation value (S13).

  As a result, the corrected gradient approaches the actual gradient earlier than the internal gradient calculated value even when the gradient suddenly changes, the initial gradient change, or during acceleration / deceleration where the deviation between the actual gradient and the internal gradient calculated value becomes large. And the gradient can be estimated with high accuracy.

Then, when the sum S of the gradient correction amount i _k which is summed with the internal slope calculated value reaches the target correction amount TGRD, thereafter, to the value added to the internal gradient calculating value is reduced from the target correction amount by DecGRD, corrected Since the rear gradient approaches the internal gradient calculation value (S14 to S18, the portion surrounded by A in FIG. 12), the corrected gradient can be prevented from overshooting the actual gradient.

  Further, when the absolute value of the acceleration of the vehicle 1 is smaller than the acceleration / deceleration determination threshold value α, the internal gradient calculation value is larger than when the absolute value of the acceleration of the vehicle 1 is larger than the acceleration / deceleration determination threshold value α. Increased the correction.

Specifically, a table defining the relationship between the gradient compensation amount i _k is a correction amount of the internal gradient calculating values for the difference between the internal slope calculation value and the navigation slope, the acceleration of the vehicle 1 is deceleration determination threshold α Prepared for each case of non-acceleration / deceleration smaller than that and acceleration / deceleration larger than the acceleration / deceleration determination threshold value α (S6, S10, FIGS. 8 and 8 are two tables superimposed), and these The gradient correction amount i _k is calculated with reference to the table.

During non-acceleration / deceleration, the accuracy of the navigation gradient and internal gradient calculation values is high, so there is no problem even if the gradient correction amount i _k is increased, and this makes it possible to bring the corrected gradient closer to the actual gradient more quickly. Further, as a method to differentiate the gradient correction amount i _k in acceleration or deceleration in a non-acceleration and deceleration, the gradient correction amount i _k for the difference between the internal slope calculation value and the navigation gradient in each case as in this embodiment It is convenient and preferable to prepare a table that defines the relationship.

  In addition, when the absolute value of the acceleration of the vehicle 1 is smaller than the acceleration / deceleration determination threshold value α, the internal gradient calculation value is obtained only when the absolute value of the time change rate of the internal gradient calculation value is larger than the upper limit change rate ΔGRDin. (S8, FIG. 10). During non-acceleration / deceleration, since the accuracy of the internal gradient calculation value is high, it is possible to determine the gradient with relatively high accuracy based on the internal gradient calculation value. Then, the correction of the internal gradient calculation value is limited to a case where the time change rate of the internal gradient calculation value is larger than the lower limit change rate ΔGRDin, so that the internal gradient calculation value is corrected only in a situation where correction is necessary. The internal gradient calculation value is frequently corrected in situations where the internal gradient calculation value does not need to be corrected (flat roads or situations where the gradient is slight), and the corrected gradient value can be prevented from fluctuating. .

  Also, the internal gradient calculation value is corrected only when the difference between the navigation gradient and the internal gradient calculation value is between the lower limit difference value ErrGrdLimdwnA (or ErrGrdLimdwnB) and the upper limit difference value ErrGrdLimupA (or ErrGrdLimupB). (S5, S9, FIG. 7, FIG. 11). As a result, the internal gradient calculation value is not corrected in a situation where the error included in the navigation gradient may be large, and the internal gradient calculation value is corrected in a situation where the navigation gradient error is large. It is possible to prevent the estimation accuracy from deteriorating.

  At this time, when the acceleration of the vehicle 1 is smaller than the acceleration / deceleration determination threshold value α, the lower limit difference value is made smaller and the upper limit difference than when the acceleration of the vehicle 1 is larger than the acceleration / deceleration determination threshold value α. The value was increased (S5, S9, FIG. 7, FIG. 11). Thereby, the chance of the correction | amendment in the non-acceleration / deceleration in which the precision of a navigation gradient and an internal gradient calculation value becomes high can be increased, and the estimation precision of a gradient can be raised more.

  Further, the internal gradient calculation value is corrected only when the navigation gradient is larger than the uphill determination threshold value LimGRDup or smaller than the descending plate determination threshold value LumGRDdwn (S2, FIG. 4). Thereby, the correction of the internal gradient calculation value is performed only in a situation where the correction of the internal gradient calculation value is necessary, and the fluctuation of the corrected gradient due to frequent correction can be prevented.

  Moreover, the internal gradient calculation value is corrected only when the absolute value of the time change rate of the navigation gradient is smaller than the upper limit change rate ΔGRD (S3, FIG. 5). When the navigation gradient changes suddenly, the error included in the navigation gradient is likely to be large, and in this situation, the gradient estimation accuracy is prevented from degrading due to the correction of the internal gradient calculation value. be able to.

  The embodiment of the present invention has been described above, but the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

11 Gradient estimation device 28 Navigation system

Claims (10)

A gradient estimation device for estimating a gradient during travel of a vehicle,
An internal gradient calculation means that calculates a weight gradient resistance acting on the vehicle based on the driving state of the vehicle, estimates a gradient during which the vehicle is traveling based on the calculated weight gradient resistance, and uses this as an internal gradient calculation value When,
A navigation gradient acquisition means for acquiring a gradient in which the vehicle is traveling from a navigation system and using the gradient as a navigation gradient;
A corrected gradient calculating means for calculating a corrected gradient by correcting the internal gradient calculated value based on a difference between the internal gradient calculated value and the navigation gradient;
A gradient estimation apparatus comprising: The gradient estimation device according to claim 1,
When the absolute value of the acceleration of the vehicle is smaller than the acceleration / deceleration determination threshold value, the corrected gradient calculating means is more than the case where the absolute value of the acceleration of the vehicle is larger than the acceleration / deceleration determination threshold value. Increasing the correction amount of the internal gradient calculation value,
A gradient estimation apparatus characterized by that. The gradient estimation device according to claim 2,
When the absolute value of the acceleration of the vehicle is smaller than the acceleration / deceleration determination threshold value, the corrected gradient calculating means is arranged only when the time change rate of the internal gradient calculated value is larger than a lower limit change rate. Correct the calculated value.
A gradient estimation apparatus characterized by that. The gradient estimation device according to any one of claims 1 to 3,
The corrected gradient calculation means corrects the internal gradient calculation value only when the difference between the navigation gradient and the internal gradient calculation value is between a lower limit difference value and an upper limit difference value.
A gradient estimation apparatus characterized by that. The gradient estimation device according to claim 4,
The post-correction gradient calculating means reduces the lower limit difference value when the acceleration of the vehicle is smaller than an acceleration / deceleration determination threshold value than when the acceleration of the vehicle is larger than the acceleration / deceleration determination threshold value. And increasing the upper limit difference value,
A gradient estimation apparatus characterized by that. The gradient estimation device according to claim 2 or 3,
When the acceleration of the vehicle is smaller than the acceleration / deceleration determination threshold, a table that defines the relationship between the difference between the internal gradient calculation value and the navigation gradient and the gradient correction amount that is the correction amount of the internal gradient calculation value And a case where it is larger than the acceleration / deceleration determination threshold value,
The corrected gradient calculating means calculates the gradient correction amount with reference to these tables.
A gradient estimation apparatus characterized by that. The gradient estimation device according to claim 6,
The corrected gradient calculating means calculates the corrected gradient by repeatedly adding the gradient correction amount to the internal gradient calculated value.
A gradient estimation apparatus characterized by that. The gradient estimation apparatus according to claim 7, comprising:
The corrected gradient calculation means sets a target correction amount based on a value obtained by subtracting the corrected gradient from the navigation gradient,
When the sum of the gradient correction amounts added to the internal gradient calculation value reaches the target correction amount, the value added to the internal gradient calculation value is decreased from the target correction amount, and the corrected gradient To the inner gradient calculation value,
A gradient estimation apparatus characterized by that. The gradient estimation device according to any one of claims 1 to 8,
The corrected gradient calculation means corrects the internal gradient calculation value only when the navigation gradient is larger than an uphill determination threshold value or smaller than a descending plate determination threshold value.
A gradient estimation apparatus characterized by that. The gradient estimation apparatus according to any one of claims 1 to 9,
The corrected gradient calculation means corrects the internal gradient calculation value only when the absolute value of the time change rate of the navigation gradient is smaller than the upper limit change rate.
A gradient estimation apparatus characterized by that.

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