Digital adaptive speed control for vehicles

• US 3,952,301 A
• Filed: 02/11/1974
• Issued: 04/20/1976
• Est. Priority Date: 02/11/1974
• Status: Expired due to Term

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Sorkin, Morris
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US05/441,100
• Time in Patent Office: 799 Days
• Field of Search: 343/7 ED, 343/7 VM, 343/5 DP
• US Class Current: 342/71
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: G01S 13/92 for velocity measurement

Abstract

A sensor, such as a radar, is mounted on a moving vehicle equipped with a speed control system which normally maintains the vehicle speed constant at a pre-set speed in the absence of a preceding vehicle within a safe distance. The sensor detects the presence of a preceding vehicle and measures the distance and closing speed of the controlled vehicle with respect to the preceding vehicle, and generates an adaptive speed signal. The adaptive speed signal modifies the error signal of the speed control system which controls either the throttle or brake to cause the controlled vehicle to match its speed to the speed of the preceding vehicle, and to maintain a safe distance from it, thereby making the adaptive speed signal vanish. The error signal may be modified by the adaptive speed signal either by decreasing the desired speed or by increasing the actual speed. The desired, actual, and adaptive speeds may all be represented by digital numbers.

Claims

1. A digital adaptive speed control for a motor vehicle comprising:

a. means for generating a first train of pulses representative of the speed of the vehicle;

b. a digital memory register coupled to said pulse generating means for storing a first digital signal representative of the desired speed of the vehicle;

c. a digital comparator coupled to said pulse generating means and to said memory register for comparing the first digital signal with a second digital signal representative of said pulse train during a predetermined period of time, and for generating an error signal;

d. a throttle actuator coupled to said comparator means;

e. a brake actuator coupled to said comparator means;

f. a radar for sensing the distance and closing speed to another vehicle ahead of the control vehicle and for developing a second pulse train representative of an adaptive speed signal;

g. a range and range rate extractor coupled to said radar for generating distance and closing speed signals;

h. a pulse gate generator coupled to said radar for generating a range gate, said digital comparator being coupled to said pulse gate generator for generating a range gate having a time duration dependent upon the vehicle speed;

i. means for coupling said radar to said digital comparator for modifying said error signal in accordance with said adaptive speed signal; and

j. means for selectively actuating said brake actuator to reduce the speed of the control vehicle in response to said adaptive speed signal.

2. An adaptive speed control as defined in claim 1 wherein a digital-to-analog converter is coupled between said comparator and said pulse generator for generating an analog signal representative of the vehicle speed and impressing it upon said pulse gate generator.

3. An adaptive speed control as defined in claim 1 wherein said radar includes a signal presence generator, and a feedback connection between said signal presence generator and said pulse gate generator for extending said range gate by a predetermined amount upon the presence of a signal from said detectors.

4. An adaptive speed control as defined in claim 1 wherein a throttle amplifier is coupled between said comparator and said throttle actuator, a brake amplifier coupled between said comparator and said brake actuator, and means for impressing said adaptive speed signal on said brake amplifier for controlling its gain, thereby to operate said brake actuator in accordance with the square of said adaptive speed signal.