Automatic speed control device for vehicle

An automatic speed control device for controlling a speed of a driver's vehicle depending on an existence of a preceding vehicle ahead of the driver's vehicle, the automatic speed control device comprising:

• a distance measuring unit for measuring a distance between the driver's vehicle and the preceding vehicle;
• a speed detecting unit for detecting a vehicle speed of the driver's vehicle;
• a target speed determining unit for determining a target speed corresponding to the distance detected by the distance measuring unit and the vehicle speed detected by the speed detecting unit;
• a speed storing section for storing the vehicle speed detected by the speed detecting unit as a set speed, in accordance with a manual operation performed by the driver;
• a selecting section for selecting a smaller speed of the target speed determined by the target speed determining unit and the set speed stored by the speed storing unit;
• and
• a speed control section for controlling the vehicle speed so as to be the smaller speed selected by the selecting unit;
• wherein, when losing the preceding vehicle, the speed control unit further controls the vehicle speed so as to maintain a vehicle speed of the driver's vehicle at a time of losing the preceding vehicle until the driver's vehicle arrives at a lost point where the preceding vehicle was lost,
• wherein, when losing the preceding vehicle while the selecting section selects the target speed, the speed control unit controls the vehicle speed so as to maintain the target speed until the driver's vehicle arrives at the lost point, and furthermore, when still losing the preceding vehicle even after the driver's vehicle has arrived at the lost point, the speed control unit further controls the vehicle speed so as to change the target speed to the set speed.

An automatic speed control device for controlling a speed of a driver's vehicle depending on an existence of a preceding vehicle traveling ahead of a driver's vehicle, the automatic speed control device comprising:

• a distance measuring unit for measuring a distance between the driver's vehicle and the preceding vehicle and an angle of the preceding vehicle to the driver's vehicle;
• a speed detecting unit for detecting a vehicle speed of the driver's vehicle;
• a steering angle detecting unit for detecting a steering angle of the driver's vehicle;
• a slope change judging section for judging whether there is a predetermined slope change at a traveling point of the preceding vehicle, on the basis of an angle of the preceding vehicle;
• a target speed determining section for determining a target speed corresponding to the distance detected by the distance measuring unit and the vehicle speed detected by the speed detecting unit;
• a speed storing section for storing the vehicle speed detected by the speed detecting unit as a set speed;
• a selecting section for selecting a smaller speed of the target speed determined by the target speed determining section and the set speed stored by the speed storing section;
• and
• a speed control section for controlling the vehicle speed so as to be the smaller speed selected by the selecting section;
• wherein, when the preceding vehicle is lost and it is judged that there exists the predetermined slope change in the vicinity of a lost point of losing the preceding vehicle by the slope change judging section, the speed control section further controls the vehicle speed so as to maintain a vehicle speed of the driver's vehicle at a time of losing the preceding vehicle.

An automatic speed control device for controlling a speed of a driver's vehicle depending on an existence of a preceding vehicle ahead of the driver's vehicle, the automatic speed control device comprising:

• a distance measuring unit for measuring a distance between the driver's vehicle and the preceding vehicle;
• a speed detecting unit for detecting a vehicle speed of the driver's vehicle;
• a target speed determining unit for determining a target speed corresponding to the distance detected by the distance measuring unit and the vehicle speed detected by the speed detecting unit;
• a speed storing section for storing the vehicle speed detected by the speed detecting unit as a set speed, in accordance with a manual operation performed by the driver;
• a selecting section for selecting a smaller speed of the target speed determined by the target speed determining unit and the set speed stored by the speed storing unit;
• and
• a speed control section for controlling the vehicle speed so as to be the smaller speed selected by the selecting unit;
• wherein, when losing the preceding vehicle, the speed control unit further controls the vehicle speed so as to maintain a vehicle speed of the driver's vehicle at a time of losing the preceding vehicle until the driver's vehicle arrives at a lost point where the preceding vehicle was lost,
• wherein, when the preceding vehicle cannot be detected by the distance measuring unit and when the lost point is included in a curve larger than a predetermined curve, the speed control section controls the vehicle speed as so t o maintain the vehicle speed at the driver's vehicle at a time of losing the preceding vehicle,
• the automatic speed control device further comprising:
• a distance measuring area judging section for judging which parts of a distance measuring area of the distance measuring unit the preceding vehicle is traveling, on the basis of the distance and the angle detected by the distance measuring unit;
• and
• a motion vector detecting section for detecting a motion vector representing that the preceding vehicle moves laterally,
• wherein, when the preceding vehicle is lost in an outside part of the distance measuring area and when the motion vector before losing the preceding vehicle directs outward, the speed control section controls the vehicle speed so as to either maintain the present vehicle speed or increase to the set speed;
• and
• wherein, when the preceding vehicle is lost in an outside part of the distance measuring area and when the motion vector before losing the preceding vehicle directs inward, the speed control section selects any one of the control methods of:
• maintaining the present vehicle speed;
• increasing the present vehicle speed to the set speed;
• and
• maintaining the present vehicle speed as long as a predetermined distance.