Adaptive vehicle cruise control system and methodology

• US 6,233,515 B1
• Filed: 12/07/1998
• Issued: 05/15/2001
• Est. Priority Date: 12/07/1998
• Status: Expired due to Term

• Current Assignee: Jaguar Cars Limited (TATA Motors Limited)
• Original Assignee: Jaguar Cars Limited (TATA Motors Limited)
• Inventors: King, Paul John, Engelman, Gerald H., Barber, Philip Alexander, Richardson, Michael Julian
• Primary Examiner(s): Chin, Gary
• Application Number:
  US09/207,007
• Time in Patent Office: 890 Days
• Field of Search: 701/93, 701/94, 701/95, 701/96, 701/300, 701/301, 180/167-169, 180/176-179, 342/454, 342/455, 340/901, 340/903, 340/904, 340/435, 340/436
• US Class Current: 701/96
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60W 2050/0009 Proportional differential [PD] controller
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2552/20 Road profile, i.e. the change in elevation or curvature of a plurality of continuous road segments
• CPC Class Codes: B60W 2552/30 Road curve radius
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance

Abstract

Disclosed herein is a headway control for an adaptive cruise control system based on a basic headway control law derived from feedback linearization techniques. The usefulness of the linear approximations is demonstrated, and basic attributes of data which are believed important to system response are introduced. Certain modifications to a basic headway controller for enabling system performance to better meet driver expectations under real road conditions are made as a result of empirical information.

Claims

1. An automotive vehicle comprising:

a powertrain comprising an engine having a throttle that is selectively operated to apply an acceleration force to the vehicle via wheels on which the vehicle is supported and propelled along an underlying surface;

a vehicle speed control for selectively throttling the engine via the throttle to null discrepancy between actual vehicle speed and a reference vehicle speed;

range and range rate apparatus for providing a range signal and a range rate signal corresponding respectively to range and range rate to an immediately preceding lead vehicle; and

a headway controller that acts via the vehicle speed control for nulling discrepancy between said range to the immediately preceding lead vehicle obtained by the range and range rate apparatus and a reference range that varies with timed headway;

wherein the range and range rate signals and a vehicle speed signal corresponding to said actual vehicle speed provide closed loop feedback to the headway controller;

wherein the headway controller develops a speed reference signal which corresponds to the reference vehicle speed and provides a speed command input to the vehicle speed control, and the speed reference signal comprises an algebraic summation of a term that is proportional to the vehicle'"'"'s own speed as measured by the vehicle speed sensor, of a term that is proportional to the difference between the reference range and the range to the immediately preceding lead vehicle as measured by the range signal, and of a term that is proportional to said range rate to the immediately preceding lead vehicle as measured by the range rate signal.

2. An automotive vehicle as set forth in claim 1 in which the vehicle further comprises a brake control system that is selectively operated to apply a deceleration force to the vehicle wheels, and the speed reference signal also provides a command signal input to the brake control system.

3. An automotive vehicle comprising:

a powertrain comprising an engine having a throttle that is selectively operated to apply an acceleration force to the vehicle via wheels on which the vehicle is supported and propelled along an underlying surface;

a vehicle speed control for selectively throttling the engine via the throttle to null discrepancy between actual vehicle speed and a reference vehicle speed;

range and range rate apparatus for providing a range signal and a range rate signal corresponding respectively to range and range rate to an immediately preceding lead vehicle; and

a headway controller that acts via the vehicle speed control for nulling discrepancy between said range to the immediately preceding lead vehicle obtained by the range and range rate apparatus and a reference range that varies with timed headway;

wherein the range and range rate signals and a vehicle speed signal corresponding to said actual vehicle speed provide closed loop feedback to the headway controller;

and wherein the headway controller develops a speed reference signal which corresponds to the reference vehicle speed and provides a speed command input to the vehicle speed control, and the headway controller executes a function for accelerating and decelerating the vehicle that is mathematically defined by a piecewise continuous surface wherein change in the speed reference signal per unit of time measurement Δ

V_ƒ

is defined as a function of both range error R_e and range rate {dot over (R)} by the maximum function;

$\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>V_f=\max <br><br>\left[\begin{array}{c}{k}_{p,s}<br><br>R_e+k_{d,s}<br><br>\stackrel{.}{R}\\ k_{p,c}<br><br>R_e+k_{d,c}<br><br>\stackrel{.}{R}\end{array}\right]$

where the values of k_p,s, k_d,s, k_p,c, and k_d,c are selected to provide relatively less rigid feel for some sets of values of said range error and said range rate and relatively more rigid feel for other sets of values of said range error and said range rate.

4. An automotive vehicle as set forth in claim 3 in which the vehicle further comprises a brake control system that is selectively operated to apply a deceleration force to the vehicle wheels, and the speed reference signal also provides a command signal input to the brake control system.

5. An automotive vehicle as set forth in claim 4 in which for a first further set of values of said range error and said range rate, the maximum function is limited to a predetermined maximum acceleration, and for a second further set of values of said range error and said range rates the maximum function is limited to a predetermined maximum deceleration.

6. An automotive vehicle comprising:

a powertrain comprising an engine having a throttle that is selectively operated to apply an acceleration force to the vehicle via wheels on which the vehicle is supported and propelled along an underlying surface;

a vehicle speed control for selectively throttling the engine via the throttle to null discrepancy between actual vehicle speed and a reference vehicle speed;

a headway controller that is operable to different modes including an adaptive cruise control mode;

range and range rate apparatus for providing a range signal and a range rate signal corresponding respectively to range and range rate to an immediately preceding lead vehicle;

wherein the range and range rate signals and a vehicle speed signal corresponding to said actual vehicle speed provide closed loop feedback to the headway controller, and the headway controller develops a speed reference signal which corresponds to the reference vehicle speed and provides a command signal input to the vehicle speed control for causing the vehicle speed control to null discrepancy between said range to the immediately preceding lead vehicle as measured by the range signal and a reference range that varies with timed headway when the adaptive cruise control mode assumes a follow state;

and upon losing the track of the immediately preceding lead vehicle while said actual vehicle speed is less than the reference vehicle speed, the headway controller is operable to transition from the follow state of the adaptive cruise control mode to a resume state of the adaptive cruise control mode to return vehicle speed toward the reference vehicle speed as a function of lateral acceleration of the vehicle;

and wherein said function of lateral acceleration of the vehicle comprises attenuating gain of the resume function in an inverse relation to the magnitude of the lateral acceleration once the lateral acceleration has exceeded a predetermined minimum magnitude.

7. An automotive vehicle as set forth in claim 6 in which said function of lateral acceleration of the vehicle further comprises completely inhibiting return of the vehicle speed toward the reference vehicle speed for said lateral acceleration exceeding a predetermined maximum magnitude.

8. An automotive vehicle comprising:

a powertrain comprising an engine having a throttle that is selectively operated to apply an acceleration force to the vehicle via wheels on which the vehicle is supported and propelled along an underlying surface;

a vehicle speed control for selectively throttling the engine via the throttle to null discrepancy between actual vehicle speed and a reference vehicle speed;

a headway controller that is operable to different modes including an adaptive cruise control mode;

range and range rate apparatus for providing a range signal and a range rate signal corresponding respectively to range and range rate to an immediately preceding lead vehicle;

wherein the range and range rate signals and a vehicle speed signal corresponding to said actual vehicle speed provide closed loop feedback to the headway controller, and the headway controller develops a speed reference signal which corresponds to the reference vehicle speed and provides a command signal input to the vehicle speed control for causing the vehicle speed control to null discrepancy between said range to the immediately preceding lead vehicle as measured by the range signal and a reference range that varies with timed headway when the adaptive cruise control mode assumes a follow state;

and upon losing the track of the immediately preceding lead vehicle while said actual vehicle speed is less than the reference vehicle speed, the headway controller is operable to transition from the follow state of the adaptive cruise control mode to a resume state of the adaptive cruise control mode to return vehicle speed toward the reference vehicle speed as a function of lateral acceleration of the vehicle;

and wherein the speed reference signal comprises an algebraic summation of a term that is proportional to the vehicle'"'"'s own speed as measured by the vehicle speed sensor, of a term that is proportional to the difference between the reference range and the range to the immediately preceding lead vehicle as measured by the range signal, and of a term that is proportional to range rate to the immediately preceding lead vehicle as measured by the range rate signal.

9. An automotive vehicle comprising;

a powertrain comprising an engine having a throttle that is selectively operated to apply an acceleration force to the vehicle via wheels on which the vehicle is supported and propelled along an underlying surface;

a vehicle speed control for selectively throttling the engine via the throttle to null discrepancy between actual vehicle speed and a reference vehicle speed;

a brake control system that is selectively operated to apply a deceleration force to the vehicle wheels;

range and range rate apparatus for providing a range signal and a range rate signal corresponding respectively to range and range rate to an immediately preceding lead vehicle; and

a headway controller that acts via the vehicle speed control for nulling discrepancy between said range to the immediately preceding lead vehicle obtained by the range and range rate apparatus and a reference range that varies with timed headway;

wherein the range and range rate signals and a vehicle speed signal corresponding to said actual vehicle speed provide closed loop feedback to the headway controller;

wherein the headway controller develops a reference speed signal which corresponds to the reference vehicle speed and provides a command input to both the vehicle speed control and the brake control system;

and the headway controller prevents the reference speed signal from causing the brake control system to apply deceleration force to the vehicle wheels whenever the range rate is positive.