Patent Application
20110015819
The disclosure of Japanese Patent Application No. 2009-167783 filed on Jul. 16, 2009 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Related Technical Fields
Related technical fields include guidance device, a guidance method, and a guidance program.
2. Description of the Related Art
A display device has been proposed for a hybrid vehicle using a motor and an engine as a drive source, in which areas that correspond to distribution ratios of a braking force of the motor and a braking force of a hydraulic brake are displayed during deceleration of the vehicle (see Japanese Patent Application Publication No. JP-A-2007-314100, paragraph 0033, for example). A running control system has also been proposed for a hybrid vehicle that indicates a level of regeneration energy recovered in a currently performed brake operation (see Japanese Patent Application Publication No. JP-A-2007-186045, paragraph 0046, for example).
The basic object of brake operation is to decelerate the current speed of the vehicle to a desired speed at a deceleration target position ahead. However, in conventional devices such as those described above, a brake operation amount required for decelerating to a desired speed at a deceleration target position is not taken into consideration, and only the level of regenerated energy recovered from the current brake operation and the like is displayed. Therefore, guidance cannot be provided to a driver regarding a brake operation amount suitable for regeneration energy recovery and for safety.
Exemplary implementations of the broad inventive principles described herein provide a guidance device, a guidance method, and a guidance program, which provide guidance to a driver regarding a brake operation amount suitable for regeneration energy recovery and for safety.
Exemplary implementations provide guidance devices, methods, and programs that acquire a current speed of the vehicle and calculate a regeneration upper limit operation amount, which is an upper limit value of the operation amount of the brake pedal when only the regenerative brake is operated, based on the current speed of the vehicle. The devices, methods, and programs acquire a deceleration target speed, acquire a deceleration target position, calculate a distance to the deceleration target position, and calculate a deceleration required operation amount of the brake pedal required for reducing the current speed of the vehicle to the deceleration target speed at the deceleration target position based on the acquired current speed of the vehicle, the acquired deceleration target speed, and the calculated distance to the deceleration target position. The devices, methods, and programs create guidance regarding the operation amount of the brake pedal based on the calculated regeneration upper limit operation amount and the calculated deceleration required operation amount, and cause the created guidance to be communicated to a user.
Following
Hereinafter, an example of a guidance device, a guidance method, and a guidance program will be described in detail with reference to the drawings.
The constitution of a guidance system according to the present example will be described first.
The current position detection processing unit 10 detects the current position of a vehicle (referred to as a “host vehicle” below) installed with the guidance device 80. Specifically, the current position detection processing unit 10 has at least one of a GPS, a geomagnetic sensor, a distance sensor, and a gyroscopic sensor (none of which are shown in the drawing), and detects the current position (coordinates), heading, and the like of the host vehicle using commonly known methods.
The vehicle speed sensor 20 outputs a rotational speed or the like of a wheel of the host vehicle. A commonly known vehicle speed sensor 20 may be used.
The accelerator mechanism 30 is a driving mechanism of the host vehicle. The accelerator mechanism 30 controls an engine and an electric motor in accordance with an operation amount (a depression amount) of an accelerator pedal (not shown in the drawing). A commonly known mechanism may constitute the accelerator mechanism 30. The accelerator mechanism 30 outputs a current operation amount of the accelerator pedal, namely an accelerator pedal current operation amount, to the guidance device 80.
The brake mechanism 40 is a braking mechanism of the host vehicle. The brake mechanism 40 is constituted from a combination of two types of brakes, a friction brake (hydraulic brake) and a regenerative brake. These two types of brakes can be operated by a brake pedal (not shown in the drawing). Specifically, the host vehicle is constituted as a hybrid vehicle having the engine and the electric motor as a drive source, wherein electric power regenerated by the braking energy of the host vehicle can be accumulated in a battery and the electric power of the battery used to drive the electric motor and the like (all of which are not shown in the drawing). The brake pedal is provided with a pedal sensor (not shown in the drawing) that detects an operation amount (a depression amount, or an amount excluding so-called play) of the brake pedal. Based on the output of the pedal sensor, a control is performed by cooperative control of the friction brake and the regenerative brake. This cooperative control of the friction brake and the regenerative brake is performed using a commonly known method through a brake control unit, a hydraulic mechanism, and the like not shown in the drawing. The brake mechanism 40 outputs a current operation amount of the brake pedal, namely a brake pedal current operation amount, to the guidance device 80.
The battery control unit 50 controls the battery that accumulates regenerated electric power. The battery control unit 50 outputs battery charge information that is information pertaining to the charge status of the battery to the guidance device 80.
The display 60 displays an image provided by the guidance device 80. The specific constitution of the display 60 may take on any form, and a flat panel display such as a commonly known liquid crystal display or organic EL display may be used.
The speaker 70 is an output unit that outputs various types of audio based on a control of the guidance device 80. The specific voice output from the speaker 70 may take on any form, and it is possible to output a synthetic voice that is generated as necessary or a pre-recorded voice.
The guidance device 80 is a guidance control unit that performs a guidance control pertaining to the operation amount of the brake pedal, and includes a controller (e.g., control unit 81) and a data storage unit 82.
The control unit 81 controls the guidance device 80. Specifically, the control unit 81 is a computer with a configuration that includes a CPU, various programs that are interpreted and executed in the CPU (including an OS and other basic control programs, and application programs that are activated in the OS to carry out specific functions), and an internal memory such as a RAM for storing the programs and various data. In particular, a program that implements the guidance process algorithm described below may be installed in the guidance device 80 through any storage medium or network, and configures various portions of the control unit 81 in substance.
The control unit 81 includes a regeneration upper limit operation amount calculation unit 81a, a safe deceleration required operation amount calculation unit 81b, a current operation amount acquisition unit 81c, and a guidance control unit 81d in terms of functional concept.
The regeneration upper limit operation amount calculation unit 81a calculates an upper limit value of the operation amount of the brake pedal when only the regenerative brake is operated (hereinafter, a “regeneration upper limit operation amount”) based on the current speed of the host vehicle.
The safe deceleration required operation amount calculation unit 81b calculates the operation amount of the brake pedal required for slowing the current speed of the host vehicle to a deceleration target speed at a deceleration target position (hereinafter, a “deceleration required operation amount”) based on the current speed of the host vehicle, the deceleration target speed, and the distance to the deceleration target position.
Here, the deceleration target position is a targeted position at which the deceleration should be achieved when decelerating the current speed of the host vehicle, and includes a position automatically specified based on only map information (e.g. a feature such as a stop point, an ETC gate of an interchange or the like, a right- or left-turn point, a T-junction, an entry to a curve having at least a predetermined curvature, or an obstacle), and any position set in the map information by the driver of the host vehicle (e.g. a stop-off location, or a destination). The deceleration target speed is a speed that should be used when the host vehicle reaches at the deceleration target position. Unless specifically noted, deceleration shall include stopping, and therefore, the deceleration target position includes a stop target position and the deceleration target speed at the stop target position is a speed of zero. Here, the safe deceleration required operation amount calculation unit 81b calculates an operation amount required for deceleration from the current position to the deceleration target position when decelerating at a constant deceleration G. In this case, the constant deceleration G is a deceleration G at which the behavior of the host vehicle is stabilized (hereinafter, a “safe deceleration G”). The safe deceleration G is not a fixed value, and instead is a value that varies depending on the current speed of the vehicle, the deceleration target speed, and the distance to the deceleration target position when the safe deceleration G is calculated. The operation amount required for deceleration when decelerating at the safe deceleration G described above is called a “safe deceleration required operation amount.”
The current operation amount acquisition unit 810 acquires the current operation amount that is the current operation amount of the brake pedal.
The guidance control unit 81d performs a guidance control pertaining to the operation amount of the brake pedal based on the regeneration upper limit operation amount calculated by the regeneration upper limit operation amount calculation unit 81a, and the safe deceleration required operation amount calculated by the safe deceleration required operation amount calculation unit 81b. The processes that are executed by these functional elements of the control unit 81 will be described in detail later.
The data storage unit 82 is a storage unit that stores programs and various data required for operation of the guidance device 80, and has a configuration that uses a hard disk (not shown in the drawing) as an external memory device, for example. However, any other storage mediums, including a magnetic storage medium such as a magnetic disk or an optical storage medium such as a DVD or Btu-ray disc, can be used in place of or in combination with the hard disk.
The data storage unit 82 has a map information database 82a. (Note that database will be abbreviated to “DB” below.) The map information DB 82a is a map information storage unit that stores map information. The map information is information required for specifying various positions, including intersections and stop points. The map information may be configured to include, for example, intersection data (such as intersection coordinates), map display data for displaying a map on the display 60, and the like. Further, the data storage unit 82 may store, in any format, information required for acquiring the regeneration upper limit operation amount, the safe deceleration required operation amount, and the current operation amount.
A guidance process executed by the guidance device 80 with the above constitution will be explained below.
Following activation of the guidance process, the control unit 81 continuously monitors whether there is a deceleration target position ahead of the host vehicle (SA1). The determination regarding whether there is a deceleration target position may be a determination of whether there is a deceleration target position that matches a predetermined condition on the road traveled by the host vehicle (on a route traveled if a travel route is set for the host vehicle, and on a road currently traveled by the host vehicle if no travel route is set for the host vehicle). The predetermined condition may be a condition regarding whether the deceleration target position is located at a distance that, using the current position as a reference, is the sum of a [distance reachable by the inertial force of the host vehicle when acceleration is stopped by turning off the accelerator at the current position (hereinafter, a “distance reachable by inertia”)] and an [extra distance for securing the time required for calculating the regeneration upper limit operation amount and the safe deceleration required operation amount (hereinafter, an “extra distance reachable by inertia”)]. Specifically, the control unit 81 acquires the current speed from the vehicle speed sensor 20 and calculates the extra distance reachable by inertia based on the acquired current speed. If the deceleration target position is located within the extra distance reachable by inertia ahead of the current position, the deceleration target position is determined to be the deceleration target position that matches the predetermined condition.
If it is determined that there is a deceleration target position (SA1: Yes), the regeneration upper limit operation amount calculation unit 81a calculates the regeneration upper limit operation amount (SA2). Operation amounts of the brake pedal in which only the regenerative brake operates and the friction brake does not operate can be found in advance in relation to the vehicle speed of the host vehicle. Therefore, data that specifies the correspondence relationship between such operation amounts of the brake pedal and the vehicle speed is stored in any format, such as a table or graph, in the data storage unit 82. Based on the current speed acquired from the vehicle speed sensor 20, the regeneration upper limit operation amount calculation unit 81a then refers to the data of the data storage unit 82 to calculate the regeneration upper limit operation amount. At such time, the regeneration upper limit operation amount calculation unit 81a may also refer to the battery charge information output from the battery control unit 50 and calculate the regeneration upper limit operation amount in consideration of the charging rate of the battery.
Next, the safe deceleration required operation amount calculation unit 81b calculates the safe deceleration required operation amount (SA3). If deceleration is performed at the safe deceleration G from the current position to the deceleration target position, for example, the operation amount of the brake pedal required for decelerating to the deceleration target speed at the deceleration target position can be calculated using a commonly known method, based on the current speed of the host vehicle, the deceleration target speed, and the distance to the deceleration target position. Thus, the safe deceleration required operation amount calculation unit 81b calculates the safe deceleration required operation amount based on the current speed acquired from the vehicle speed sensor 20, the deceleration target speed specified using a predetermined method, and the distance from the current position to the deceleration target position determined at SA1 as matching the predetermined condition. Here, the method of specifying the deceleration target speed may take on any form. For example, deceleration target speeds corresponding to deceleration target positions may be stored in advance in the map information DB 82a, and read out as necessary to specify the deceleration target speed. Alternatively, if the deceleration target position is a stop point, a stopping off location, or a destination, the deceleration target speed may be set to zero, whereas if the deceleration target position is the entry to a curve having at least a predetermined curvature, the deceleration target speed may be set to a speed at which the curve can be safely navigated by the host vehicle and a speed that corresponds to the curvature of the curve. The distance from the current position to the deceleration target position can be found from the deceleration target position determined as matching the predetermined condition, the current position of the host vehicle output from the current position detection processing unit 10, and the map information of the map information DB 82a.
Next, the guidance control unit 81d determines whether a predetermined display timing has been reached at which the regeneration upper limit operation amount and the safe deceleration required operation amount should be displayed (SA4). The method of specifying the display timing may take on any form, and the display timing may be set to any timing when it is effective to inform the driver of the host vehicle of the regeneration upper limit operation amount and the safe deceleration required operation amount. For example, if the accelerator pedal is not in use and deceleration target position is within the distance reachable by inertia as described above from the current position of the host vehicle, it is determined that some form of braking is required for safe deceleration and the display timing is determined as now. Here, whether the accelerator pedal is in use may be determined based on the accelerator pedal current operation amount output from the accelerator mechanism 30.
If the display timing is determined as now (SA4: Yes), the guidance control unit 81d displays the regeneration upper limit operation amount calculated at SA2 and the safe deceleration required operation amount calculated at SA3 on the display 60 in a predetermined display format (SA5). An example of the display will be described in more detail later.
Next, the guidance control unit 81d determines whether the brake pedal was operated (SA6). Specifically, the current operation amount acquisition unit 81c acquires the current operation amount of the brake pedal from the brake mechanism 40, and the guidance control unit 81d determines whether the brake pedal was operated based on the acquired current operation amount. If the brake pedal was operated (SA6: Yes), the guidance control unit 81d displays the current operation amount acquired by the current operation amount acquisition unit 81c, and both the regeneration upper limit operation amount and the safe deceleration required operation amount displayed at SA5, on the display 60 in a predetermined display format (SA7). An example of the display will be described in more detail later.
The control unit 81 subsequently monitors whether the host vehicle has reached the deceleration target position of SA1 (SA8). If the deceleration target position has not been reached (SA8: No), the control unit 81 proceeds to SA2. Similarly thereafter, the process from SA2 to SA8 is repeatedly performed until the host vehicle reaches the deceleration target position of SA1, such that the regeneration upper limit operation amount, the safe deceleration required operation amount, and the current operation amount are constantly updated to the latest value and displayed on the display 60. If the host vehicle has reached the deceleration target position of SA1 (SA8: Yes), the control unit 81 proceeds to SA1 and continuously monitors whether there is a subsequent deceleration target position ahead of the host vehicle (SA1). If there is a subsequent deceleration target position (SA1: Yes), the process from SA2 to SA8 is executed again for the subsequent deceleration target position. The process from SA2 to SA8 is similarly executed thereafter for each deceleration target position.
Examples of the display at SA5 and SA7 of
Before explaining the individual content of the display examples, the display format shared by the display examples will be described. As shown in
The area 91 displays a current operation amount display section 92 that shows the current operation amount, a regeneration upper limit operation amount display section 93 that shows the regeneration upper limit operation amount, and a safe deceleration required operation amount display section (a deceleration required operation amount display section) 94 that shows the safe deceleration required operation amount. These amounts, using the upper limit operation amount of the brake pedal indicated at the upper limit operation position P2 as a reference, are displayed at positions that correspond to the degree of approach toward the upper limit operation amount. The specific display mode of these amounts may take on any farm, and the amounts are shown here as display needles that rotate around the center of curvature. The display needles are preferably displayed easily distinguishable from one another. For example, the current operation amount display section 92 may be shown with a black display needle, the regeneration upper limit operation amount display section 93 with a green display needle, and the safe deceleration required operation amount display section 94 with a red display needle.
The display example in
The display example in
The display example in
The display example in
The display example in
According to the present example described above, the regeneration upper limit operation amount and the safe deceleration required operation amount are calculated, and a guidance control pertaining to the operation amount of the brake pedal is performed based on the regeneration upper limit operation amount and the safe deceleration required operation amount. Therefore, the driver can be provided with guidance based on the brake pedal operation amount that enables recovery of regeneration energy, and the brake pedal operation amount required for slowing the current speed of the vehicle to the deceleration target speed at the deceleration target position. Thus, the driver can perform a brake operation while knowing the regeneration upper limit operation amount and the deceleration required operation amount, and can easily perform deceleration that considers safety in addition to the efficient recovery of braking energy.
Further, the current operation amount is calculated in addition to the regeneration upper limit operation amount and the deceleration required operation amount, and a guidance control pertaining to the operation amount of the brake pedal is performed based on the regeneration upper limit operation amount, the deceleration required operation amount, and the current operation amount. Therefore, the driver can be provided with guidance based on the current operation amount, as well as the regeneration upper limit operation amount and the deceleration required operation amount. Thus, the driver can perform a brake operation that considers the current operation amount of the brake pedal as well as the regeneration upper limit operation amount and the deceleration required operation amount, and can more easily perform deceleration that considers safety in addition to the efficient recovery of braking energy.
The guidance control is performed using the upper limit operation amount of the brake pedal as a reference. Therefore, the driver can take into account the relative relationships among the regeneration upper limit operation amount, the deceleration required operation amount, and the current operation amount using the upper limit operation amount of the brake pedal as a reference.
The guidance control performed shows the current operation amount display section 92, the regeneration upper limit operation amount display section 93, and the deceleration required operation amount display section 94 within the display area 90 spanning from a position that corresponds to a non-operation state of the brake pedal to a position that corresponds to the upper limit operation amount of the brake pedal. Therefore, the driver can grasp the relative relationships among the regeneration upper limit operation amount, the deceleration required operation amount, and the current operation amount using the non-operation state and upper limit operation amount of the brake pedal as a reference. In addition, the driver can easily grasp these relative relationships by viewing the regeneration upper limit operation amount, the deceleration required operation amount, and the current operation amount that are shown on the same display area.
An exemplary implementation of the inventive principles was explained above. However, the specific configuration and units for implementing these principles may be modified and improved in any manner or form within the scope of the technical ideas of the inventive principles. Examples of such modifications are explained below.
The problems to be solved and the effects of the inventive principles described herein are not limited to the examples described herein and may vary depending on the environment in which the principles are applied and the detailed configuration of the implementation. The above problems may be only partially solved, and the above effects only partially achieved.
In the above example, the host vehicle is a hybrid vehicle. However, the an electric vehicle that uses only an electric motor as a drive source may be the host vehicle.
The determination regarding whether there is a deceleration target position is made based on the map information stored in the map information DB 82a. However, an area in front of the host vehicle may be imaged by a camera or the like and subject to image analysis to determine the existence of a feature ahead of the host vehicle and the type of feature, for example. It may be determined that there is a deceleration target position if the existence of a feature of a predetermined type (e.g. a stop sign) is determined.
The regeneration upper limit operation amount, the safe deceleration required operation amount, or the current operation amount may be calculated using a method other than the calculation methods described above. For example, gradient information pertaining to the gradient of the road surface from the current position to the deceleration target position may be included in the map information. The gradient information may then be read out from the map information as necessary and used in the calculation of these amounts. In addition, the guidance control may be performed based only on the regeneration upper limit operation amount and the safe deceleration required operation amount, with the current operation amount omitted. In this case as well, a display such as shown in
Guidance that further considers a comfortable deceleration required operation amount may be performed as guidance based on the deceleration required operation amount. Here, the comfortable deceleration required operation amount is a deceleration required operation amount when decelerating at a constant deceleration G from the current position to the deceleration target position. The comfortable deceleration required operation amount is also a deceleration required amount when deceleration is performed at a deceleration G at which the behavior of the host vehicle is stable and which the driver finds comfortable (hereinafter, a “comfortable deceleration G” and a fixed value of 0.2 G, for example). The method of guidance control that considers the comfortable deceleration required operation amount may be any method. For example, in the display examples of
A deceleration G different from that described in the example may also be applied as the safe deceleration G. For example, assuming that deceleration is ultimately performed at the comfortable deceleration G (a brake operation is performed at the comfortable deceleration required operation amount), a deceleration G required for performing constant deceleration from the current position to the deceleration target position to achieve the target deceleration speed may equal or exceed the comfortable deceleration G by a predetermined deceleration G. In such case, the host vehicle may be decelerated at an intermediary deceleration G (hereinafter, an “intermediate deceleration G”) until the host vehicle reaches a position that is a predetermined distance ahead of the current position (hereinafter, an “intermediate position”), and then the host vehicle may be decelerated at the comfortable deceleration G until the host vehicle reaches the deceleration target position from the intermediate position. The safe deceleration G described above may be applied as the intermediate deceleration G. Further, a distance calculated based on the current speed of the host vehicle and the speed the host vehicle should use at the current position (a speed determined based on a deceleration curve for decelerating at the comfortable deceleration G up to the deceleration target position) may be applied as the predetermined distance. Specifically, the safe deceleration required operation amount calculation unit 81b may calculate a deceleration required operation amount for decelerating at the safe deceleration G from the current position to the intermediate position, based on the current speed of the vehicle, the speed the host vehicle should use at the current position, and the distance to the intermediate position. The guidance control unit 81d may then provide guidance to the driver regarding the deceleration required operation amount. If the intermediate position has been reached, the safe deceleration required operation amount calculation unit 81b may calculate the comfortable deceleration required operation amount for decelerating at the comfortable deceleration G from the intermediate position to the deceleration target position, based on the current speed of the host vehicle, the deceleration target speed, and the distance to the deceleration target position. The guidance control unit 81d may then provide guidance to the driver regarding the comfortable deceleration required operation amount. Thus, a different deceleration G may be applied as the targeted deceleration G depending on the need and a plurality of deceleration Gs may be combined in a multiple-stage manner.
In the above example, the operation amount of the brake pedal was described as an amount excluding so-called play. However, such play may be included, and in this case, guidance is preferably provided to the driver such that the brake pedal operation amount that corresponds to play can be distinguished from the brake pedal operation amount that corresponds to non-play. As an example of such guidance, in the display examples of
The timing for calculating the regeneration upper limit operation amount, the safe deceleration required operation amount, the comfortable deceleration required operation amount, or the current operation amount may be a timing other than that described above. For example, although the regeneration upper limit operation amount and the safe deceleration required operation amount are calculated before determining whether the display timing has been reached, the regeneration upper limit operation amount and the safe deceleration required operation amount may be calculated after determining that the display timing has been reached.
The timing for displaying the regeneration upper limit operation amount, the safe deceleration required operation amount, the comfortable deceleration required operation amount, or the current operation amount on the display 60 may be a timing other than that described above. In the above example, an example of the timing for displaying the regeneration upper limit operation amount and the safe deceleration required operation amount is described as a time when the accelerator pedal is not in use and the deceleration target position is within a distance reachable by inertia from the current position of the host vehicle. However, regardless of whether the accelerator pedal is in use, the regeneration upper limit operation amount and the safe deceleration required operation amount may be displayed when the deceleration target position is within a distance reachable by inertia from the current position of the host vehicle, and releasing the accelerator pedal may be encouraged.
The regeneration upper limit operation amount, the safe deceleration required operation amount, the comfortable deceleration required operation amount, or the current operation amount may be sequentially output, or in addition to the sequential output, when the respective amounts have finally reached a predetermined state or a predetermined relationship, notification that the final state has been reached may be output. For example, when the safe deceleration required operation amount exceeds the regeneration upper limit operation amount, guidance informing that safe deceleration cannot be achieved through the regeneration brake alone may be displayed on the display 60 and output by voice from the speaker 70.
Any guidance mode may be used in place of or in addition to the display on the display 60 regarding the regeneration upper limit operation amount, the safe deceleration required operation amount, the comfortable deceleration required operation amount, or the current operation amount. For example, output may be performed using the speaker 70. Examples of such output include the output of a sound informing that an amount is equal to or greater than a predetermined reference value, a sound informing that a relative relationship of the amounts is a predetermined relationship, or a sound supporting the driver's brake operation based on a relative relationship of the amounts. Specific examples of this last example include the output of a synthetic voice informing the driver to maintain the current pedal operation when the state of
Even when display is performed using the display 60, the amounts may be displayed in a mode other than the display mode described above. For example, when using display needles to show the regeneration upper limit operation amount display section, the safe deceleration required operation amount display section, the comfortable deceleration required operation amount display section, or the current operation amount display section, in order to distinguish the amounts from one another, the thickness and type of display needle may be varied, or the flashing, lighting, and interval of the display needle may be varied. A display screen may also be used to display in place of the display needles. A display example using such a display screen is shown in
While various features have been described in conjunction with the examples outlined above, various alternatives, modifications, variations, and/or improvements of those features and/or examples may be possible. Accordingly, the examples, as set forth above, are intended to be illustrative. Various changes may be made without departing from the broad spirit and scope of the underlying principles.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-167783 | Jul 2009 | JP | national |
