System for automatically controlling vehicle speed

• US 4,621,705 A
• Filed: 10/09/1984
• Issued: 11/11/1986
• Est. Priority Date: 12/06/1983
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Etoh, Yoshiyuki
• Primary Examiner(s): Weakley, Harold W.
• Application Number:
  US06/658,529
• Time in Patent Office: 763 Days
• Field of Search: 180/167, 180/168, 180/169, 364/461, 364/456, 364/457, 364/458, 364/424, 340/901, 340/902, 340/903, 340/904
• US Class Current: 180/169
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 2754/30 Longitudinal distance
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9319 Controlling the accelerator
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/9323 Alternative operation using light waves
• CPC Class Codes: G01S 2013/9324 Alternative operation using ultrasonic waves
• CPC Class Codes: G01S 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

In a system and method for automatically controlling a vehicle'"'"'s speed, the rate of change of the inter-vehicle distance per predetermined unit of time is calculated from the detected inter-vehicle distance between the controlled vehicle and a preceding vehicle, a basic safe inter-vehicle distance is corrected according to the calculated rate of change of the inter-vehicle distance per predetermined time, and the vehicle speed is controlled according to the difference between the corrected safe inter-vehicle distance and the detected inter-vehicle distance.

Claims

1. A system for automatically controlling the speed of a vehicle, comprising:

(a) means for detecting vehicle speed and outputting a first signal indicative thereof;

(b) means for calculating a safe inter-vehicle distance between the controlled vehicle and another vehicle preceding same on the basis of the vehicle speed detected by said vehicle speed detecting means;

(c) means for detecting the actual inter-vehicle distance between the vehicle and the preceding vehicle and outputting a second signal indicative thereof;

(d) means responsive to the second signal for calculating the rate of change of the inter-vehicle distance per predetermined unit of time;

(e) means for correcting the calculated safe inter-vehicle distance according to the rate of change of inter-vehicle distance calculated by said inter-vehicle change rate calculating means; and

(f) means for controlling the vehicle speed according to the difference between the corrected safe inter-vehicle distance and the detected actual inter-vehicle distance, said vehicle speed controlling means selecting a rate of change of increase of the vehicle speed from a plurality of predetermined values when the difference between the corrected safe inter-vehicle distance and the actual vehicle distance increases and selecting a rate of change of decrease of the vehicle speed from among a plurality of predetermined values when the difference between the corrected safe inter-vehicle distance and the actual inter-vehicle distance decreases, the selected rate of increase or decrease in vehicle speed being detected by determining in which of a plurality of predetermined ranges the difference between the actual and corrected safe inter-vehicle distance lies, said vehicle speed controlling means controlling the vehicle speed together with an overdrive solenoid valve of an automatic transmission of the vehicle released when determining that an absolute value of the difference between the actual and corrected safe inter-vehicle distance is within or greater than a maximum one of said predetermined ranges.

2. The system as set forth in claim 1, wherein the predetermined ranges are selected on the basis of the dynamic characteristics of the vehicle'"'"'s engine and transmission.

3. The system as set forth in claim 1, wherein said vehicle controlling means maintains the vehicle speed unchangedly when determining that an absolute value of the difference between the actual and corrected safe inter-vehicle distance is below a minimum one of said plurality of said predetermined values.