JP2005300462A - Travel-supporting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a travel-supporting apparatus capable of prolonging the wear life time of brake pads. <P>SOLUTION: The travel-supporting apparatus relates an estimated amount of wear of the brake pads to a plurality of travel routes A and B, from a point P to a second point Q included in map data and displays a travel route related to a minimum estimated amount of wear of the brake pads. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a travel support device that uses wear amount information of a brake pad.

In recent years, it has become clear that there is a conflicting relationship between noise and vibration characteristics generated from a brake and the wear life of a brake pad. When the noise and vibration characteristics are improved, the wear life of the brake pad tends to be shortened. However, there is a demand for extending the wear life of the brake pad and reducing maintenance costs. In addition, the apparatus which detects the wear amount of a brake pad and gives a warning is described in the following patent document 1 and patent document 2, for example.
Japanese Patent Laid-Open No. 7-108884 JP 2002-303344 A

  However, because the amount of wear on the brake pads depends on its performance, it has been considered that the wear life cannot be essentially extended.

  An object of this invention is to provide the driving assistance device which can extend the wear life of a brake pad.

  In order to solve the above-described problem, a driving support device according to the present invention includes a means for associating an estimated wear amount of a brake pad with each of a plurality of driving routes from a first point to a second point included in map data, And a display means for displaying a travel route associated with the estimated wear amount of the brake pad.

  In this case, since the travel route that gives the estimated wear amount of the minimum brake pad is displayed on the display means, the user can select and travel the travel route as needed, and therefore the wear life of the brake pad. Can be extended.

  In addition, the driving support device according to the present invention provides a warning that warns when a value obtained by subtracting the estimated amount of wear of the brake pad from the current amount of the brake pad when the specific driving route is selected is below a threshold value. The apparatus further comprises means.

  In this case, it is possible to know the brake pad replacement time before traveling on a specific travel route.

  According to the driving support device of the present invention, the wear life of the brake pad can be extended.

  Hereinafter, after describing the amount of wear of the brake pads, the travel support device according to the embodiment will be described.

  FIG. 1 is a graph of a temperature T of a brake pad (brake rotor) with respect to energy E of the vehicle. As energy E increases, temperature T also increases. These functions are given by T = f (E), and as E increases, T increases monotonously.

  FIG. 2 is a graph showing the relationship of the wear amount W with respect to the temperature T of the brake pad. As the temperature T increases, the wear amount W increases. These functions are given by W = g (T), and as T increases, W increases monotonously.

  FIG. 3 is a graph showing the relationship of the wear amount W to the energy E. This function is a composite function (W = g (f (E))) of the above-described function, and when the energy E increases, the wear amount W increases rapidly. That is, if the vehicle energy E is known, the temperature T and the wear amount W can be estimated. The vehicle energy E depends on the vehicle weight m, which corresponds to the braking energy. The amount of wear with respect to the braking energy depends on the brake specifications, the outside air temperature, and the cooling characteristics of the brake pads.

  Here, consider the energy E of a vehicle traveling on a specific road.

  FIG. 4 is a diagram showing unit areas included in the three-dimensional road map data. In this unit area, a road R extending from north to south is set. For example, the address (n, m) of this unit area will be described as (8, 1). If the road R has a height difference H within a single region, the potential energy of the vehicle will differ depending on the direction in which the vehicle travels. The higher the vehicle, the higher the potential energy, and the higher the vehicle, the higher the braking energy for obtaining a desired braking force.

  Here, the direction toward north and east is defined as a positive direction (+), and the direction toward south and west is defined as a negative direction (−). For this direction setting, the direction of the road at the end position in the traveling direction in the unit area may be determined. In this example, the direction going north on the road is (+), and the direction going south is (-). That is, if the traveling direction is determined, the height information H can be signed.

  FIG. 5 is a diagram showing values of basic data associated with the unit area.

According to this basic data, when the vehicle travels in the (+) direction, it is possible to obtain positional energy corresponding to the height difference H ₊ = + 100 m, and the average speed V ₊ = 30 km / h expected when traveling on this road. The average braking period N ₊ = 3 seconds is specified. When the vehicle travels in the (−) direction, it is possible to obtain the potential energy for the height difference H ₋ = −100 m, in other words, the potential energy for 100 m is lost, but the average expected when traveling on this road It is specified that the speed per hour is V ₊ = 60 km / h, and the average brake period N _{+ is} 2 seconds.

  The height difference is data obtained from the map information, the average hourly speed, and the average brake period from the road traffic information. These basic data are stored in the database of the storage device in association with the addresses of the unit areas.

The potential energy of an object with mass m at a height H is mgH (g is gravitational acceleration), and the kinetic energy of an object with velocity V is given by (1/2) × mV ² . Therefore, the energy E ^* of the vehicle when traveling on the road R in the unit area depends on the sum of mgH ₊ and (1/2) × mV ₊ ^{2 for} the (+) direction, and for the (−) direction. mgH _- and (1/2) × mV _- depend on the ² of the sum.

When data on the frequency of braking for vehicles having such energy E is also stored in the database as the brake period N, the value obtained by multiplying the vehicle's energy E ^* by the expected brake period N controls the brake wear amount. Effective vehicle energy E, corresponding to the braking energy required in the unit area. Therefore, based on the effective vehicle energy E data associated with the address of the unit area of the map data, the estimated value of the brake pad wear amount W when the vehicle travels on the road in the section is calculated. (See FIG. 3).

For example, (+) direction of the vehicle effective energy _{E +} is, a, b, as coefficients _{c, E + = a × (} 1/2) × mV + 2 + b × mgH +) in × c × _{N +} By substituting this into W ₊ = g (f (E ₊ ), it is possible to estimate the wear amount W from the energy. Each coefficient a, b, c and function f, g in this estimated wear amount equation Can be obtained by solving a plurality of simultaneous equations obtained by substituting the actual brake pad wear amount W obtained by repeating trial running with an actual vehicle into this equation. is there.

  Here, the above-mentioned unit area is generalized and described.

FIG. 6 is a diagram showing generalized data values associated with the unit areas. Assume that the address (n, m) = (k, l) of this unit area. Corresponding to this address (k, l), the height difference H ₊ , average speed V ₊ , average brake period N ₊ , when traveling in the ( ₊ ) direction, the height difference H ₋ , average speed V when traveling in the (−) direction. _-, mean braking period N _- is stored in the database of the storage device.

FIG. 7 is a diagram showing a generalized value of the brake pad wear amount W associated with the unit area. By introducing the basic data shown in FIG. 6 into the estimated wear amount W described above, the wear amount of the brake pad when traveling in the (+) direction within the unit section of the address (k, l), that is, The estimated wear amount W ₊ and the estimated wear amount W ₋ when traveling in the (−) direction can be obtained. The values of the estimated wear amounts W ₊ (k, l) and W ₋ (k, l) at the address (k, l) of the unit area of the map data are stored in the database in association with the addresses.

  When the vehicle is scheduled to travel on a specific road in the unit area of the address (k, l), first, it is determined whether the traveling direction of the vehicle is the (+) direction or the (−) direction. Stores the azimuth of the end position in the direction of travel in the unit area of the road selected at the time of route search, and positive basic data corresponding to the positive / negative information ((+) (-)) associated with the stored azimuth Alternatively, either negative basic data is read together with the address of the unit area.

That is, if the traveling direction is the (+) direction, the value of W ₊ (k, l) is determined as the estimated wear amount, and if the traveling direction is the (−) direction, the value of W ₋ (k, l) is determined as the estimated wear amount. decide.

  FIG. 8 shows routes A and B connecting the point P and the point Q set on the wide-area road map data. It is assumed that the routes A and B are searched by the distance priority route search in the car navigation device. The estimated wear amount data shown in FIGS. 6 and 7 is stored in the storage device as wear amount map data in association with the address (k, l) of the unit area of the road map data.

For the calculation of the estimated wear amount for each travel route, first, for each route A and B, all addresses (k, l) of the unit area through which the route passes are extracted. Direction data indicating the traveling direction (+) and (−) of the vehicle is attached to each address (k, l) extracted for each route. All the estimated wear amounts (W ₊ , W ₋ ) for each direction data associated with each extracted address (k, l) are extracted, and all the extracted estimated wear amounts are integrated for each route.

  By integrating the estimated wear amount for each address through which route A passes, the estimated wear amount when route A is passed can be calculated. Further, by integrating the estimated wear amount for each address through which the route B passes, the estimated wear amount when the route B is passed can be calculated. If a plurality of routes from point P to Q are selected and the selected plurality of routes are arranged in order of decreasing wear amount, a route search for wear amount priority can be executed.

  FIG. 9 is a diagram of a driving support device for performing the above-described calculation.

  This travel support device includes a navigation system 2 to which current position data obtained from the GPS 1, ON / OFF data of the brake switch 7 and vehicle speed data 9 are input, and a wear amount priority route based on the calculation result of the navigation system 2. Is provided, and a warning lamp 8 for displaying a warning is provided. The navigation system 2 includes road map data 4, wear amount map data 3 storing a wear amount corresponding to an address of a unit area in the road map data, and a calculation unit 5 that performs a calculation according to an input.

  FIG. 10 is a flowchart showing the control in the calculation unit 5.

  When the user operates the navigation system 2 and selects the route search mode (S1), it is determined whether or not the priority condition during the search is the amount of wear (S2). If the priority condition at the time of the search is not the wear amount, it is determined whether or not the route search is the distance priority (S3), and if it is neither, the route search is performed with the priority condition of another item. If the priority condition is distance in step S3, a distance priority route search is performed.

  As a simple example of the distance priority route search, the map data 4 is divided into a plurality of unit areas, the length of the road is defined in the unit areas, and the adjacent unit areas are started from the point P. It is determined whether or not the road position at the boundary is continuous, and the unit area satisfying this condition is stored in the direction of the point Q, and the sum of the road distances in the unit area stored when Q is reached is In the order of shortening, the route corresponding to the selected unit area is displayed on the display unit 6.

  Various distance-preferred route search methods are known, and a conventional commercially available navigation program may be used.

  In step S2, if the priority condition at the time of the search is the wear amount, a route search program that prioritizes the wear amount is executed. First, the current position P indicated by the GPS 1 is set. It is assumed that the destination Q is determined by the user. Then, a plurality of routes from the current position P to the destination Q are searched. Here, first, a conventionally known distance priority route search method is used.

That is, since the wear amount is generally smaller as the mileage is shorter, by performing a distance-first route search, a plurality of routes A and B from the point P to Q are selected, and the estimated wear amount in each route is obtained. Then, it is obtained in association with the wear amount map data 3 (S4). For the calculation of the estimated wear amount for each route, the wear amount map data 3 (FIGS. 7 and 8) storing the wear amount for each unit area associated with the road map data 4 is used. The calculation method of the estimated wear amount for each route is as described above. That is, the estimated amount of wear (W ₊ , W ₋ ) corresponding to the traveling direction for each address (k, l) of the unit area through which each searched route passes is accumulated in the route total route, so that the vehicle The estimated amount of wear when passing through can be calculated.

  Next, the selected routes A and B are rearranged in the order of the smallest estimated wear amount, and the retrieved routes are displayed on the display 6 in the order of the route having the smallest estimated wear amount (S5). A sorting program is used for this rearrangement.

In addition, the calculating part 5 can perform a learning function. That is, when the basic data (V ₊ , N ₊ , V ₋ , N ₋ ) is changed, the estimated wear amount (W ₊ , W ₋ ) at the address (k, l) in the unit area is changed. be able to. More specifically, each basic data (V ₊ , N ₊ , V ₋ , N ₋ ) has an initial value, and the measured basic data (V ₊ , N ₊ , V ₋ , N ₋ ) If the difference exceeds the tolerance by a predetermined number of times compared to the value, the initial value and the average value of the measured basic data (V ₊ , N ₊ , V ₋ , N ₋ ) are stored as new basic data, The value of the estimated wear amount (W ₊ , W ₋ ) is rewritten based on the formula obtained by the method (update function).

  In order to execute this learning function, the output of the brake switch 7 is input as the brake frequency, and the vehicle speed data 9 for obtaining the average vehicle speed is input, and the above-described basic data can be rewritten according to these data. It is also possible to set basic data according to the time such as traffic hours, in which case the time element is added to the learning function, that is, the basic data update function for each time zone is set. You can also.

  In the above method, the estimated wear amount for each route is calculated by accumulating the estimated wear amount in the unit area already stored in the database for each selected route, but this is based on only basic data. A database stored for each area may be used, and for each route search, the estimated wear amount for each unit area may be calculated based on the basic data using the above-described method and integrated. In the above description, the estimated wear amount is stored for each unit area. However, this sets the estimated wear amount for each individual road section, and sets the estimated wear amount corresponding to the road section included in each route. It can also be set as the structure which calculates the estimated amount of wear (integrated value) for every route by integrating | accumulating.

  FIG. 11 is a flowchart showing another control in the calculation unit 5.

The calculation unit 5 calculates the estimated wear amount at the time of the route search, but a value (remaining amount) obtained by subtracting the estimated wear amount of the brake pad from the current brake pad amount when a specific travel route is selected. , to determine if below the threshold W _T (S10), if it falls below the warning lamp (warning means) for performing a warning to the user to turn on the (S11). In this case, it is possible to know the brake pad replacement time before traveling on a specific travel route. Note that the current amount of the brake pad can be detected using a sensor such as a stroke sensor that detects the amount of the brake pad.

  As described above, the above-described travel support device associates the estimated wear amount W of the brake pad with each of the plurality of travel routes A and B from the first point P to the second point Q included in the map data 4. (S4) and a display (display means) 6 for obtaining a travel route that gives the estimated wear amount of the minimum brake pad (S5) and displaying the travel route. Since the travel route that gives the estimated amount of wear of the minimum brake pad is displayed on the display 6, the user can select and travel the travel route as necessary, and therefore, the wear life can be extended. .

  The present invention can be used for a driving support device that uses wear amount information of a brake pad.

It is a graph of temperature T of a brake pad (brake rotor) with respect to energy E which a vehicle has. It is a graph which shows the relationship of the amount of wear W with respect to the temperature T of a brake pad. 6 is a graph showing the relationship of wear amount W to energy E. It is a figure which shows the unit area | region contained in map data. It is a figure which shows the value of the data matched with the unit area | region. It is a figure which shows the value of the data matched with the unit area in general. It is a figure which generalizes and shows the value of the amount of wear matched with the unit field. Routes A and B connecting the points P and Q set on the wide-area road map data are shown. It is a figure of the driving assistance apparatus for performing a calculation. 3 is a flowchart showing control in a calculation unit 5. 10 is a flowchart showing another control in the calculation unit 5.

Explanation of symbols

2 ... navigation system, 3 ... wear amount map data, 4 ... road map data, 5 ... arithmetic unit, 6 ... display, 7 ... brake switch, 8 ... warning Ramp, 9 ... Vehicle speed data.

Claims (2)

In the driving support device,
Means for associating the estimated amount of wear of the brake pads for each of a plurality of travel routes from the first point to the second point included in the map data;
Display means for displaying a travel route associated with an estimated wear amount of the smallest brake pad;
A driving support apparatus comprising: The system further comprises warning means for giving a warning when a value obtained by subtracting an estimated amount of wear of the brake pad from a current amount of the brake pad when the specific travel route is selected is below a threshold value. Item 2. The driving support device according to Item 1.

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