Process and system for controlling the speed of a vehicle

• US 6,347,273 B1
• Filed: 04/17/2000
• Issued: 02/12/2002
• Est. Priority Date: 08/11/1997
• Status: Expired due to Term

• Current Assignee: Volvo Car Corporation (AB Volvo)
• Original Assignee: Volvo Car Corporation (AB Volvo)
• Inventors: Wendeberg, Staffan, Adelsson, Per
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US09/485,432
• Time in Patent Office: 666 Days
• Field of Search: 701/96, 701/93, 180/170-179
• US Class Current: 701/96
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60W 2754/30 Longitudinal distance
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle

Abstract

The present invention refers to a method to control the speed of a vehicle by means of a cruise control device, essentially by arranging the cruise control device in at least one of: a cruise control state (13), in which the speed of the vehicle is controlled preferably with regard to a selected constant speed (V_det), a retardation state (14), in which the speed of the vehicle (V_curr) is controlled towards a determined constant speed (V_det), an acceleration state (15), in which the speed alteration is achieved preferably manually, an inactive state (16), in which the system is temporary or permanently switched off, and a distance control state (17), in which substantially a distance of the vehicle to a vehicle ahead is controlled. The method further comprises the step of arranging the cruise control in a temporary state (18), in which a speed (V_curr) at transition time to this state is maintained.

Claims

1. A method to control the speed of a vehicle by means of a cruise control device, which communicates with at least one detector for scanning a field in front of the vehicle, the cruise control device being arranged to assume at least the following control states:

a first state, in which the speed of the vehicle (V_curr) is controlled with regard to a selected constant speed (V_det),

a second state, in which the speed of the vehicle (V_curr) is controlled with regard to a speed at which a distance (d_s) to at least one nearest vehicle in front is maintained substantially constant,

third state, in which the speed of the vehicle (V_curr) is maintained substantially constant, the cruise control further being arranged to change from said first state to said second state when a vehicle in front is detected in the sensing field of the detector,

wherein the cruise control assumes the third state from said second state when the vehicle in front departs from the sensing field of the detector, and that the cruise control device remains in the third state until;

the driver takes over the control of the speed of the vehicle, or

the detector detects that the vehicle in front is within the sensing field of the detector whereby the cruise control device assumes the second state from the third state.

2. A method according to claim 1, wherein the cruise control device changes to the first state from the third state.

3. A method according to claim 2, wherein the transition occurs if the system is activated manually.

4. A cruise control system of a vehicle, including a computer unit, detectors and control devices, which computer unit, when activated, is arranged to control the speed of the vehicle by means of the control devices with regard to a selected speed and information received from the detector, said information containing a distance to and/or speed of another vehicle in front, the cruise control being arranged to assume at least following control states:

a first state, in which the speed of the vehicle (V_curr) is controlled with regard to a selected constant speed (V_det),

a second state, in which the speed of the vehicle (V_curr) is controlled with regard to a speed at which a distance (d_s) to at least one nearest vehicle in front is maintained substantially constant,

a third state, in which the speed of the vehicle (V_curr) is maintained substantially constant, the cruise control further being arranged to change from said first state to said second state when the vehicle in front is detected in the sensing field of the detector, wherein the computer unit is further arranged to put the cruise control in the third state from said second state when the vehicle in front departs from the sensing field of the detector, and that the cruise control remains in the third state until;

signals are received from a pedal detector that the driver has taken over the control of the speed of the vehicle, or

the detector signals the computer unit that a vehicle in front is detected within the sensing field of the detector whereby the computer unit instructs the cruise control to assume the second state from the third state.

5. The system according to claim 4, wherein the detector for distance and/or speed is a radar unit.

6. The system according to claim 4, wherein the detector is located in a front section of the vehicle, preferably outside the vehicle cabin.

7. The system according to claim 4, wherein the system is connected to a detector for indication of appearance of a road.

8. The system according to claim 4, wherein the distance and/or speed detector is arranged to indicate the distance with a time difference.