Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
2001-08-06
2003-04-08
Louis-Jacques, Jacques H. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S098000, C180S168000, C180S169000
Reexamination Certificate
active
06546327
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a running control apparatus and method.
2. Description of Related Art
According to a running control apparatus described in JP-A-9-323628, a brake that reduces rotation of a wheel is actuated when the inter-vehicle distance between a vehicle and a preceding vehicle (hereinafter referred to as an inter-vehicle distance) becomes equal to or less than a set value. Therefore, the vehicle can be reliably decelerated, and excessively close approach to a vehicle ahead can be avoided.
However, the above-identified running control apparatus actuates the brake without consideration as to whether a preceding vehicle is running in the same lane as the vehicle. Therefore, if the preceding vehicle is not running in the same lane as the vehicle, the apparatus may unnecessarily actuate the brake.
SUMMARY OF THE INVENTION
It is one object of the invention to avoid unnecessary actuation of a brake by a running control apparatus that controls the state of running of a vehicle based on a relative positional relationship between the vehicle and a preceding vehicle. This object can be achieved by implementing a running control apparatus and method according to the aspects of the invention described hereinafter. It should be understood that the technical features described in this specification and combinations thereof are not limited to the following embodiments. Furthermore, a plurality of features described herein do not have to be adopted altogether. The invention includes one or more of the various features used singularly or together.
According to one aspect of the invention, a running control apparatus and method controls a running state of a vehicle based on a relative positional relationship between the vehicle and a preceding vehicle running ahead of the vehicle in a preset area. It determines a probability that an object detected in the preset area is the preceding vehicle that is running ahead in the same lane as the vehicle. Then, the invention actuates a brake that retards rotation of a wheel of the vehicle when a relative positional relationship between the vehicle and the preceding vehicle indicates that the vehicle should be decelerated, wherein the relative positional relationship between the vehicle and the preceding vehicle indicating that the vehicle should be decelerated includes a state in which a the determined probability is equal to or greater than a preset probability.
In the running control apparatus described as above, the brake is actuated if the probability that a body detected in the preset area is a preceding vehicle running in the same lane as the vehicle (hereinafter, simply referred to as “same-lane probability”) is equal to or greater than a set probability value. When the same-lane probability is low, the brake is not actuated. Therefore, unnecessary operation of the brake can be avoided. A running control apparatus and method described above may also prohibit actuation of the brake if the same-lane probability is less than the set probability.
The relative positional relationship between the vehicle and a preceding vehicle may be represented by the relative position of the preceding vehicle to the vehicle as well as the changing speed of the relative position, the changing acceleration thereof, or specific data that cause such change, for example, the speed of the vehicle or the preceding vehicle, the acceleration thereof, etc. The relative position may be expressed as a point in a plane coordinate system defined by a direction parallel to a predicted running line of the vehicle (which may be a straight line extending through the center of the vehicle in the longitudinal direction or a curve determined taking into account the steering angle or the running speed, the yaw rate, etc.) and a direction perpendicular thereto (lateral direction of the vehicle). The inter-vehicle distance refers to the distance between the vehicle and a preceding vehicle. If the predicted running line is a curve, the inter-vehicle distance may be expressed as a straight-line or a curve. Furthermore, if the predicted running line is a curve, the relative position may be expressed as a point in an orthogonal plane coordinate system obtained by developing the curve into a straight line. Based on the relative position, it is possible to determine whether the preceding vehicle is located in a specific area that is predetermined in an orthogonal plane coordinate system, or to acquire a probability that the preceding vehicle is located in the specific area. The result of such determination and the probability may represent the relative positional relationship. A value obtained by dividing the inter-vehicle distance by the running speed of the vehicle may also represent the relative positional relationship.
The same-lane probability determining process may include determining whether an object detected in the preset area is the preceding vehicle so as to acquire a probability that the body determined as a preceding vehicle is running in the same lane as the vehicle. This preceding vehicle determining process may include determining whether the object detected in the preset area is in a moving state or a stationary state. The moving state determining process may determine whether the object body is in a stationary state based on, for example, the running speed of the vehicle and a relative speed between the vehicle and the object body. If an approaching speed, that is, a kind of the relative speed, is greater than or equal to a set approaching speed (which may be either a constant value or a value that is set based on the running speed of the vehicle), or if the relative speed is substantially equal to the running speed of the vehicle (e.g., if the absolute value of a difference between the aforementioned two speeds is less than or equal to a positive set speed difference value), it may be determined that the object body is in a stationary state. The preceding vehicle determining process may include discriminating whether the preseecinf vehicle is at least one of a vehicle running on the opposite lane and a vehicle passing an intersection. The process for determining whether a vehicle is running on the opposite lane is operable to determine that a target body is an oncoming vehicle if the approaching speed of the vehicle with respect to the target body is greater than the running speed of the vehicle by at least a set approaching speed. The process for determining whether a vehicle is passing an intersection is operable to determine that a target body is a vehicle running on the crossroad if, for example, the absolute value of the moving speed of the target body in a direction perpendicular to the predicted running line of the vehicle is greater than or equal to a set moving speed. The preceding vehicle determining process may include determining that the detected object is a vehicle (which may or may not include a two-wheeled vehicle) when the detected object has a size (at least one of the height and width) larger than a preset size, and determining that the detected object is not the vehicle when the detected object has a size smaller than the preset size.
The same-lane probability of a preceding vehicle may be determined, for example, based on a relative position of the preceding vehicle determined as mentioned above, that is, a relative position thereof in a direction perpendicular to a direction parallel to the predicted running line of the vehicle. That is, the smaller the deviation of the preceding vehicle from the predicted running line of the vehicle in a perpendicular direction becomes, the higher the same-lane probability becomes. Furthermore, as will be described later, the same-lane probability may be determined by dividing the area defined by the orthogonal plane coordinate system mentioned above into a plurality of areas, and correlating the individual divided areas and values of the same-lane probability so as to be pre-stored. In this case, the value corresponding to the area to which the relative posi
Furui Nobuyuki
Hattori Akira
Miyakoshi Hironori
Louis-Jacques Jacques H.
Toyota Jidosha & Kabushiki Kaisha
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