Data processing: vehicles – navigation – and relative location – Relative location – Collision avoidance
Reexamination Certificate
2000-08-18
2002-07-02
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Relative location
Collision avoidance
C701S030000, C701S070000, C701S096000, C340S901000, C340S008100, C340S435000, C340S436000, C342S070000, C342S129000
Reexamination Certificate
active
06415230
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to methods and apparatuses for assisting vehicle operator braking action of a vehicle.
To enhance safety of a car and passengers in present-day road traffics, efforts are being made to support the operator in routine driving operations.
In this direction, antilock braking systems (ABS) have been proposed and adopted to enhance longitudinal vehicle stability in dynamically critical conditions in braking process.
“Automatic distance regulation” (ADR) systems have been proposed that are intended to detect and carry out a controlled braking action to control the distance of a vehicle from other vehicles and/or stationary objects in the direction of vehicle motion. JP-A 7-144588 discloses a system whereby traveling speed and deceleration of a vehicle in front are determined using a Doppler sensor and a vehicle speed sensor, which are on a vehicle to be controlled, and a safe distance from the vehicle in front is determined in response comparison of the traveling speed of the vehicle in front with a predetermined value of 15 km/h. In this system, a driver is warned and an automatic braking action is initiated if the distance from the vehicle in front becomes less than the safe distance.
Other systems have been proposed that are intended to initiate braking action before the operator of a vehicle initiates braking action. JP-A 6-24302 discloses a system whereby, when a foot of the operator leaves an accelerator pedal, two micro switches are both closed to energize a solenoid for activating a brake pedal. Energizing the solenoid pulls the brake pedal to partially activate a braking system before the foot of the operator is stepped on the brake pedal.
A disadvantage of such systems as disclosed in JP-A 7-144588 and JP-A 6-24302 is that the correction of the motion of a vehicle takes place consistently and with no opportunity for the operator to exercise control. Because of the requirements of the regulating algorithm, a controlling action by such systems will take place quite early so that the braking action need not be executed too abruptly. Hence, the systems will respond even in situations that a practiced operator would have negotiated himself with no problems. As a result, the operator will experience a repeated automatic intervention in the control of the vehicle, which is actually necessary in only a few cases from his or her point of view, and will consider such intervention as unwarranted interference so that such systems are unlikely to meet with much acceptance.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a vehicle operator braking action assisting method and apparatus, which overcome the disadvantage of the prior art.
Another object of the present invention is to provide a method and apparatus of this kind that will prevent a vehicle operator from considering a repeated automatic intervention in the control of the vehicle as unwarranted interference without sacrificing the advantages of a vehicle operator braking action assisting system.
For this purpose, in a method or an apparatus according to the present invention, a detection system on a vehicle to be controlled detects obstacles, which are in or near the direction of motion of the vehicle, and provides corresponding data to a control unit. In addition, the vehicle has, or certain of its components are provided with, vehicle condition sensors for detecting characteristic parameters of the condition or state of motion of the vehicle and transmitting data regarding these parameters to the control unit, and vehicle operator demand sensors for detecting characteristic parameters of the power or brake demand of the operator and transmitting data regarding these parameters to the control unit. From the data reported concerning the obstacles, the vehicle condition parameters and the operator demand parameters, the control unit ascertains a whether a braking action by the vehicle operator is needed. The control unit determines a target stand-by brake pressure and generates a command for adjustment of brake pressure to the target stand-by pressure. The apparatus includes a braking system operable by the vehicle operator. The braking system has a temporary stand-by state in which brake pressure is adjusted toward the target brake pressure. The braking system is operable to make a shift to the stand-by state only after the control unit has determined that braking action by the vehicle operator is needed. In the stand-by state, the brake pressure as high as the target stand-by brake pressure actuates the brake, producing minimum possible vehicle deceleration. Since the brake pressure will drop to zero or disappear upon termination of the stand-by state and the vehicle deceleration produced in the stand-by state is at required minimum level unnoticeable by the vehicle operator, the vehicle operator is prevented from considering such an automatic intervention in the control of the vehicle as unwarranted interference without sacrificing the advantages of a vehicle operator braking action assisting system.
It is especially advantageous if the apparatus includes an antilock braking system and/or an electronic dynamic regulating system, since in that case the motion of the vehicle will be more controllable even during braking and under critical road conditions. Since such systems are now standard equipment in many vehicles, the apparatus for assisting vehicle operator braking action may advantageously be combined with or integrated into such conventional systems.
The arrangement for detecting the condition of the vehicle includes sensors for detecting traveling speed of the vehicle (or vehicle speed) and weight of the vehicle.
The arrangement may include sensors and a control unit to determine the coefficient of force transmission, i.e., the traction, between the vehicle tires and the roadway, so that the prevailing road conditions can be detected. In this way, readings for maximum possible target stand-by brake pressure can be so derived, which may be subject to variations even during the temporary stand-by state, for example if the roadway is wet or slippery.
As sensors for detection of power or brake demand of the vehicle operator, conventional sensors for detecting whether a brake pedal of the braking system is depressed or released and for detecting stroke of an accelerator pedal are used.
As sensors for detection of the obstacles located in or near the direction of motion of the vehicle, conventional radar sensors employing laser, whose application is familiar to those skilled in the art, are used, However, any other types of sensors that permit an adequate preview of the range of motion of the vehicle and which are suitable for service under rough vehicle condition may be used.
In one embodiment, the control unit continuously detects a traveling speed of a vehicle to be controlled and continuously calculates a distance from a vehicle in front, relative speed, and a criterion distance based on the traveling speed, the distance and the relative speed. If the criterion is transgressed, i.e., the distance becomes equal to or less than the criterion distance, the control unit determines that braking action by the vehicle operator is needed and triggers stand-by brake pressure regulation in the temporary stand-by state. The stand-by state is terminated when the control unit subsequently determines depression of the brake pedal or when the control unit subsequently determines that the distance from the vehicle in front becomes greater than the criterion distance. In the stand-by state, the control unit continuously determines the target stand-by pressure as a function of the traveling speed and weight of the vehicle, and the brake pressure as high as the target stand-by pressure is applied to the brake. According to this function, the target stand-by pressure is relatively high at higher speeds, while it is relatively low at low speeds, and at intermediate speeds, with the same speed, the target stand-by pressure becomes higher as wei
Inoue Hideaki
Kobayashi Akihiko
Maruko Naoki
Tamura Minoru
Cuchlinski Jr. William A.
Nissan Motor Co,. Ltd.
To Tuan C
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