Methods and devices for controlling distance between vehicles

Claim 1

A method for controlling a distance between trailing and leading vehicles comprising the steps of: (a) detecting the velocity of the trailing vehicle; (b) detecting the relative velocity of the trailing and leading vehicles; (c) calculating a minimum safety distance between said two vehicles depending on said respective detected velocities under the assumption that maximum braking forces are applied, respectively, to said two vehicles; (d) calculating an optimum safety distance between said two vehicles depending on said respective detected velocities under the assumption that selective and desirable braking forces are applied, respectively, to said two vehicles; (e) detecting the actual separation distance between said two vehicles; (f) calculating the difference between said actual distance and said optimum safety distance; (g) calculating the difference between said optimum and minimum safety distances; (h) dividing said difference between said actual distance and said optimum safety distance by said difference between said optimum and minimum safety distances and generating an instruction signal responsive thereto; and (i) accelerating the vehicle velocity of said trailing vehicle when said signal is larger than zero and reducing the vehicle velocity of said trailing vehicle when said signal is less than zero.

Claim 2

A method for controlling a distance between trailing and leading vehicles comprising the steps of: (a) detecting the velocity of the trailing vehicle; (b) detecting the relative velocity of the trailing and leading vehicles; (c) calculating a minimum safety distance between said two vehicles depending on said respective detected velocities under the assumption that maximum braking forces are applied, respectively, to said two vehicles; (d) calculating an optimum safety distance between said two vehicles depending on said respective detected velocities under the assumption that selective and desirable braking forces are applied, respectively, to said two vehicles; (e) detecting the actual separation distance between said two vehicles; (f) calculating the difference between said actual distance and said optimum safety distance; (g) calculating the difference between said optimum and minimum safety distances; (h) dividing said difference between said actual distance and said optimum safety distance by said difference between said optimum and minimum safety distances and generating an instruction signal responsive thereto; and (i) accelerating the vehicle velocity of said trailing vehicle when said signal is larger than zero and reducing the vehicle velocity of said trailing vehicle when said signal is less than zero.

Claim 4

A device for a trailing vehicle for controlling the separation distance between trailing and leading vehicles comprising: a first terminal for applying an electric voltage proportional to the actual separation distance between the two vehicles; a second terminal for applying an electric voltage proportional to the relative velocity of the two vehicles; a third terminal for applying an electric voltage proportional to the velocity of said trailing vehicle; first circuit means coupled to said second and third terminals for providing an output signal dependent on the velocity of said leading vehicle; second circuit means connected to said first circuit means for calculating the stopping distance of said leading vehicle depending on said leading vehicle velocity on the assumption that a predetermined braking force is applied to said leading vehicle; third circuit means connected to said third terminal for calculating the stopping distance of said trailing vehicle depending on said trailing vehicle velocity on the assumption that a predetermined braking force is applied to said trailing vehicle; fourth circuit means connected to said first circuit means for calculating the stopping distance of said leading vehicle depending on said leading vehicle velocity on the assumption that a predetermined maximum braking force is applied to said leading vehicle; fifth circuit means connected to said third terminal for calculating the stopping distance of said trailing vehicle depending on said trailing vehicle velocity on the assumption that a predetermined maximum braking force is applied to said trailing vehicle; sixth circuit means connected, respectively, to said first and third terminals and said second and third circuit means for calculating an optimum safety distance between said two vehicles and generating an output signal proportional to the difference between said actual separation distance between said two vehicles and said optimum safety distance; seventh circuit means connected, respectively, to said second, third, fourth and fifth circuit means for calculating a minimum safety distance between said two vehicles and generating an output signal proportional to the difference between said optimum safety distance and said minimum safety distance; a divider for dividing the output signal of said sixth circuit means by the output signal of said seventh circuit means and generating an output signal responsive thereto; eighth circuit means connected to said divider for generating a first output signal to accelerate said trailing vehicle velocity when the output signal of said divider is larger than zero and a second output signal to reduce said trailing vehicle velocity when the output signal of said divider is less than zero; and, actuating means for receiving the first and second output signals of said eighth circuit to thereby accelerate or reduce said trailing vehicle velocity.

Claim 5

A device for a trailing vehicle for controlling the separation distance between trailing and leading vehicles comprising: a first terminal for applying an electric voltage proportional to the actual separation distance between the two vehicles; a second terminal for applying an electric voltage proportional to the relative velocity of the two vehicles; a third terminal for applying an electric voltage proportional to the velocity of said trailing vehicle; first circuit means coupled to said second and third terminals for providing an output signal dependent on the velocity of said leading vehicle; second circuit means connected to said first circuit means for calculating the stopping distance of said leading vehicle depending on said leading vehicle velocity on the assumption that a predetermined braking force is applied to said leading vehicle; third circuit means connected to said third terminal for calculating the stopping distance of said trailing vehicle depending on said trailing vehicle velocity on the assumption that a predetermined braking force is applied to said trailing vehicle; fourth circuit means connected to said first circuit means for calculating the stopping distance of said leading vehicle depending on said leading vehicle velocity on the assumption that a predetermined maximum braking force is applied to said leading vehicle; fifth circuit means connected to said third terminal for calculating the stopping distance of said trailing vehicle depending on said trailing vehicle velocity on the assumption that a predetermined maximum braking force is applied to said trailing vehicle; sixth circuit means connected, respectively, to said first and third terminals and said second and third circuit means for calculating an optimum safety distance between said two vehicles and generating an output signal proportional to the difference between said actual separation distance between said two vehicles and said optimum safety distance; seventh circuit means connected, respectively, to said second, third, fourth and fifth circuit means for calculating a minimum safety distance between said two vehicles and generating an output signal proportional to the difference between said optimum safety distance and said minimum safety distance; a divider for dividing the output signal of said sixth circuit means by the output signal of said seventh circuit means and generating an output signal responsive thereto; eighth circuit means connected to said divider for generating a first output signal to accelerate said trailing vehicle velocity when the output signal of said divider is larger than zero and a second output signal to reduce said trailing vehicle velocity when the output signal of said divider is less than zero; and, actuating means for receiving the first and second output signals of said eighth circuit to thereby accelerate or reduce said trailing vehicle velocity.