Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-06-29
2001-02-06
Chin, Gary (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S028000, C348S118000
Reexamination Certificate
active
06185492
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle steering control apparatus and, more particularly, to a vehicle steering control apparatus which assists a steering effort so that a moving line of the vehicle matches a target moving line.
2. Description of the Related Art
Conventionally, as disclosed in Japanese Laid-Open Patent Application No. 7-104856, an apparatus for generating a steering force, when an actual moving line of a vehicle deviates from a previously determined moving line (hereinafter referred to as a predetermined line), so that the vehicle is moved in a direction in which the actual moving line is shifted closer to the predetermined line. The above-mentioned conventional apparatus has a mechanism for detecting a range of a lane on which the vehicle is moving and a mechanism for detecting a range of area in which the vehicle is moving in the lane. Additionally, the above-mentioned apparatus has a mechanism for generating a steering torque so as to return the vehicle to a middle of the lane when the vehicle is shifted toward a side of the lane. Hereinafter, this steering torque is referred to as a returning steering torque.
According to the above-mentioned apparatus, when the moving line of the vehicle deviates from the predetermined line, such a situation can be conveyed to a driver of the vehicle by generating a returning steering torque. Additionally, the driver of the vehicle provided with the above-mentioned conventional apparatus can easily return the vehicle to the predetermined line by being assisted by the returning steering torque. Thus, according to the above-mentioned conventional apparatus, the vehicle can be easily and safely maintained to move on the predetermined line
Generally, a moving line which provides a comfortable feel to a driver differs from driver to driver. However, in the above-mentioned conventional apparatus, a fixed line is always set without consideration of such difference among individuals. In the above-mentioned conventional apparatus, the returning steering torque may act to resist a steering effort by the driver when a moving line desired by the driver does not match the predetermined line. In this respect, the above-mentioned conventional apparatus is not always optimum in assisting a steering effort by a driver.
Additionally, the above-mentioned conventional apparatus can alert the driver by automatically generating a returning steering torque when the vehicle is shifted to a side of the-lane on which the vehicle is moving due to some reasons. Thus, according to the above-mentioned conventional apparatus, the vehicle is prevented from deviating from the lane in which the vehicle should be maintained. However, there may be an obstacle such as a motorcycle on the lane. In such a case, the vehicle must move a side of the lane so as to avoid the obstacle. However, the above-mentioned conventional apparatus generates a returning steering torque so as to return the vehicle to the middle of the lane. Accordingly, the driver of the vehicle is required to make a steering effort to resist the returning steering force when an attempt is made to move along a side of the lane so as to avoid an obstacle. Thus, the above-mentioned conventional apparatus may provide a difficulty in maintaining movement of a vehicle along a side of a lane when the vehicle must move the side of the lane so as to avoid an obstacle.
As mentioned above, the conventional apparatus has a problem in that a driver cannot control a vehicle to move a desired line within a lane in which the vehicle is moving since the conventional apparatus always generates a steering torque to maintain the vehicle on a fixed line or always generates a steering torque proportional to a distance between the fixed line and the vehicle.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a vehicle steering control apparatus in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a vehicle steering control apparatus which controls a steering torque to move the vehicle toward a line desired by a driver or appropriate for circumstances of the vehicle.
Another object of the present invention is to provide a vehicle steering control apparatus which controls a steering torque to provide a good steering characteristic vehicle when a driver attempts to move the vehicle on a side of a lane on which the vehicle is moving while preventing the vehicle from deviating from the lane.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a vehicle steering control apparatus recognizing a lane on which a vehicle is moving and controlling a steering torque of the vehicle so that the vehicle moves along the lane, the vehicle steering control apparatus comprising:
reference line setting means for setting a plurality of reference lines which extend along the lane and are arranged parallel to each other in a direction of a width of the lane;
target moving line selecting means for selecting a target moving line from among the plurality of reference lines in accordance with a state of movement of the vehicle; and
returning steering torque generating means for generating a steering torque for shifting a moving line of the vehicle toward the target moving line.
According to the present invention, the steering torque is controlled so that the moving line of the vehicle matches the target moving line. The target moving line is determined to be one of the plurality of reference lines set on the lane, which target moving line is optimum for a state of movement of the vehicle. Accordingly, in the present invention, the steering torque is controlled so that the vehicle moves on the moving line most appropriate for the state of movement of the vehicle.
In the above-mentioned invention, the target moving line selecting means may select one of the reference lines which approximates a steering operation line achieved by a steering effort performed by a driver of the vehicle as the target moving line.
Accordingly, the target line is determined to be one of the reference lines which approximates the steering operation line, that is, a line on which the driver attempts to move the vehicle.
Additionally, the vehicle steering control apparatus according to the present invention may further comprise:
deviation preventing area setting means for setting a deviation preventing area on a side of the lane; and
deviation preventing torque generating means for generating a steering torque for moving the vehicle toward a middle of the lane when the moving line of the vehicle overlaps with the deviation preventing area.
According to the above-mentioned invention, if the moving line of the vehicle is shifted to a side of the lane, the moving line may overlap the deviation preventing area. This generates a torque (hereinafter referred to as a deviation preventing torque) which moves the vehicle toward the middle of the lane. According to the deviation prevention torque, the vehicle is effectively prevented from deviating from the lane.
Additionally, the vehicle steering control apparatus according to the present invention may further comprise:
circumstances recognizing means for recognizing circumstances of a moving path of the vehicle; and
control gain changing means for changing a magnitude of the steering torque generated by the deviation preventing torque generating means in accordance with the circumstances of the moving path.
In this invention, the magnitude of the deviation preventing torque is changed in accordance with the circumstances of a moving path of the vehicle. The circumstances of the moving path of the vehicle includes one which allows deviation of the vehicle from the lane and one which cannot allow deviation of the vehicle from the lane. In the present invention, the deviation preventing torque is set to be larger as the necessity of prevention of deviation is increased. Accordingly, deviation of the vehicle can be pos
Goto Takeshi
Kagawa Kazunori
Satoh Kunihito
Chin Gary
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Toyota Jidosha & Kabushiki Kaisha
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