Automatic speed control system for automotive vehicles

• US 5,731,977 A
• Filed: 09/15/1995
• Issued: 03/24/1998
• Est. Priority Date: 09/20/1994
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Satoh, Hiroshi, Matsumura, Toshio, Taniguchi, Ikuhiro, Oshiage, Katsunori
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/528,870
• Time in Patent Office: 921 Days
• Field of Search: 364/426.041, 364/426.044, 364/460, 364/461, 364/431.07, 180/167-170, 180/176-179, 123/350, 123/352, 342/454, 342/455, 340/903, 340/904
• US Class Current: 701/96
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60K 31/047 the memory being digital
• CPC Class Codes: B60K 31/107 the memory being digital
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16H 61/21 Providing engine brake control

Abstract

An automatic speed control system for an automotive vehicle comprises a vehicle-speed sensor, a throttle actuator adjusting an opening angle of a throttle, a brake actuator adjusting a brake-fluid pressure applied to wheel cylinders, and a switching-operation decision unit controlling the switching from one of a driving-force control of the throttle actuator and a braking-force control of the brake actuator to the other. A first arithmetic circuit calculating a command signal value for the throttle actuator and a second arithmetic circuit calculating a command signal value for the brake actuator are designed to provide transition durations. The decision unit acts to continue either one or the other control executed prior to a transition for its transition duration.

Claims

1. An automatic speed control system for an automotive vehicle, comprising:

detection means for detecting a vehicle speed of the vehicle;

acceleration means for providing an increased acceleration exerted on the vehicle by automatically adjusting a driving force applied to road wheels;

deceleration means for providing an increased deceleration exerted on the vehicle by automatically adjusting a braking force applied to the road wheels;

first arithmetic means for calculating a value of a first command signal to be sent to said acceleration means, based on a target vehicle speed and the vehicle speed detected by said detection means;

second arithmetic means for calculating a value of a second command signal to be sent to said deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means; and

decision means for switching from one of a driving-force control of said acceleration means and a braking-force control of said deceleration means to another, so that, during said driving-force control, said driving-force control is continued until the value of said first command signal reaches a first predetermined threshold and said driving-force control is switched to said braking-force control when said first predetermined threshold is reached, and so that, during said braking-force control, said braking-force control is continued until the value of said second command signal reaches a second predetermined threshold and said braking-force control is switched to said driving-force control when said second predetermined threshold is reached, during a simultaneous occurrence of said first command signal having a value greater than said first predetermined threshold and said second command signal having a value greater than said second predetermined threshold.

2. An automatic speed control system for an automotive vehicle, comprising:

detection means for detecting a vehicle speed of the vehicle;

acceleration means for providing an increased acceleration exerted on the vehicle by automatically adjusting a driving force applied to road wheels;

deceleration means for providing an increased deceleration exerted on the vehicle by automatically adjusting a braking force applied to the road wheels;

first arithmetic means for calculating a value of a first command signal to be sent to said acceleration means, based on a target vehicle speed and the vehicle speed detected by said detection means;

second arithmetic means for calculating a value of a second command signal to be sent to said deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means; and

decision means for switching from one of a driving-force control of said acceleration means and a braking-force control of said deceleration means to another,

wherein a first group of control gains used in said first arithmetic means and a second group of control gains used in said second arithmetic means are preset to provide transition durations in which said first command signal having a value greater than a first predetermined threshold and said second command signal having a value greater than a second predetermined threshold occur concurrently,

wherein said decision means selectively outputs one of said first and second command signals to continue the corresponding one of said driving-force control and said braking-force control, executed prior to a transition, for each of said transition durations.

3. An automatic speed control system for an automotive vehicle, comprising:

detection means for detecting a vehicle speed of the vehicle;

acceleration means for providing an increased acceleration exerted on the vehicle by automatically adjusting a driving force applied to road wheels;

deceleration means for providing an increased deceleration exerted on the vehicle by automatically adjusting a braking force applied to the road wheels;

first arithmetic means for calculating a value of a first command signal to be sent to said acceleration means, based on a target vehicle speed and the vehicle speed detected by said detection means;

second arithmetic means for calculating a value of a second command signal to be sent to said deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means; and

decision means for switching from one of a driving-force control of said acceleration means and a braking-force control of said deceleration means to another,

wherein a first group of control gains used in said first arithmetic means and a second group of control gains used in said second arithmetic means are preset to provide transition durations in which said first command signal having a value greater than a first predetermined threshold and said second command signal having a value greater than a second predetermined threshold occur concurrently,

wherein said driving-force control is continued for said transition duration in which the value of said first command signal is decreasingly controlled toward said first predetermined threshold and then said driving-force control is switched to said braking-force control when said first predetermined threshold is reached, and said braking-force control is continued for said transition duration in which the value of said second command signal is decreasingly controlled toward said second predetermined threshold and then said braking-force control is switched to said driving-force control when said second predetermined threshold is reached.

4. The system as claimed in claim 3, wherein said acceleration means comprises a throttle actuator which variably adjusts an opening angle of a throttle and said deceleration means comprises a brake actuator which supplies a controlled brake fluid pressure to wheel cylinders by an external fluid pressure source.

5. The system as claimed in claim 4, wherein said first and second arithmetic means calculate the respective values of said first and second command signals from equations:

space="preserve" listing-type="equation">θ

=Kp×

(V-Vd)+Ki×

∫

(V-Vd)dt+Kd×

dV/dt

space="preserve" listing-type="equation">P=Ka×

(V-Vd)+Kb×

∫

(V-Vd)dt+Kc×

dV/dt

where θ

denotes the value of said first command signal indicative of the opening angle of the throttle, V denotes the vehicle speed detected by said detection means, Vd denotes said target vehicle speed, three coefficients Kp, Ki and Kd denote said first group of control gains, P denotes the value of said second command signal indicative of said controlled brake fluid pressure, and three coefficients Ka, Kb and Kc denote said second group of control gains.

6. An automatic speed control system for an automotive vehicle, comprising:

detection means for detecting a vehicle speed of the vehicle;

acceleration means for providing an increased acceleration exerted on the vehicle by automatically adjusting a driving force applied to road wheels;

main deceleration means fluidly connected to a hydraulic brake system for providing an increased deceleration exerted on the vehicle by automatically adjusting a braking force applied to the road wheels;

auxiliary deceleration means for producing an auxiliary braking force applied to the road wheels without utilizing the hydraulic brake system;

first arithmetic means for calculating a value of a first command signal to be sent to said acceleration means, based on a target vehicle speed and the vehicle speed detected by said detection means;

second arithmetic means for calculating a value of a second command signal to be sent to said main deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means;

third arithmetic means for calculating a value of a third command signal to be sent to said auxiliary deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means; and

decision means for switching from one of a driving-force control of said acceleration means and an auxiliary braking-force control of said auxiliary deceleration means to another, and for switching from one of said auxiliary braking-force control of said auxiliary deceleration means and a braking-force control of said main deceleration means to another, so that, during said driving-force control, said driving-force control is continued until the value of said first command signal reaches a first predetermined threshold and said driving-force control is switched to said auxiliary braking-force control when said first predetermined threshold is reached, and so that, during said auxiliary braking force control, said auxiliary braking-force control is continued until the value of said third command signal reaches one of the upper and lower predetermined thresholds and said auxiliary braking-force control is switched to said driving-force control when said upper predetermined threshold is reached and to said braking-force control when said lower predetermined threshold is reached, and so that, during said braking-force control, said braking-force control is continued until the value of said second command signal reaches a second predetermined threshold and said braking-force control is switched to said auxiliary braking-force control when said second predetermined threshold is reached, during a simultaneous occurrence of said first command signal having a value greater than said first predetermined threshold and said third command signal having a value greater than said lower predetermined threshold or during a simultaneous occurrence of said second command signal having a value greater than said second predetermined threshold and said third command signal having a value greater than said upper predetermined threshold.

7. The system as claimed in claim 6, wherein said acceleration means comprises a throttle actuator which variably adjusts an opening angle of a throttle, and said main deceleration means comprises a brake actuator which supplies a controlled brake fluid pressure to wheel cylinders by an external fluid pressure source, and said auxiliary deceleration means comprises an automatic gearchange system which automatically changes a gear ratio.

8. The system as claimed in claim 6, wherein said acceleration means comprises a throttle actuator which variably adjusts an opening angle of a throttle, and said main deceleration means comprises a brake actuator which supplies a controlled brake fluid pressure to wheel cylinders by an external fluid pressure source, and said auxiliary deceleration means comprises an exhaust brake system which constricts a flow of exhaust gases coming from an engine to increase an exhaust back pressure.

9. The system as claimed in claim 6, wherein said acceleration means comprises a throttle actuator which variably adjusts an opening angle of a throttle, and said main deceleration means comprises a brake actuator which supplies a controlled brake fluid pressure to wheel cylinders by an external fluid pressure source, and said auxiliary deceleration means comprises an electric retarder which converts a part of the driving torque to electric energy.

10. An automatic speed control system for an automotive vehicle, comprising:

detection means for detecting a vehicle speed of the vehicle;

acceleration means for providing an increased acceleration exerted on the vehicle by automatically adjusting a driving force applied to road wheels;

main deceleration means for providing an increased deceleration exerted on the vehicle by automatically adjusting a braking force applied to the road wheels;

auxiliary deceleration means for producing an auxiliary braking force applied to the road wheels without utilizing the hydraulic brake system;

first arithmetic means for calculating a value of a first command signal to be sent to said acceleration means, based on a target vehicle speed and the vehicle speed detected by said detection means;

second arithmetic means for calculating a value of a second command signal to be sent to said main deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means;

third arithmetic means for calculating a value of a third command signal to be sent to said auxiliary deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means; and

decision means for switching from one of a driving-force control of said acceleration means and an auxiliary braking-force control of said auxiliary deceleration means to another, and for switching from one of said auxiliary braking-force control of said auxiliary deceleration means and a braking-force control of said main deceleration means to another;

wherein a first group of control gains used in said first arithmetic means and a third group of control gains used in said third arithmetic means are preset to provide first transition durations between said driving-force control and said auxiliary braking-force control in which said first command signal having a value greater than a first predetermined threshold and said third command signal having a value greater than a lower predetermined threshold occur concurrently, and said third group of control gains used in said third arithmetic means and a second group of control gains used in said second arithmetic means are preset to provide second transition durations between said auxiliary braking-force control and said braking-force control in which said third command signal having a value greater than an upper predetermined threshold and said second command signal having a value greater than a second predetermined threshold occur concurrently,

wherein said decision means selectively outputs one of said first, second and third command signals to continue the corresponding one of said driving-force control, said auxiliary driving-force control and said braking-force control, executed prior to a transition, for each of said first and second transition durations.

11. An automatic speed control system for an automotive vehicle, comprising:

detection means for detecting a vehicle speed of the vehicle;

acceleration means for providing an increased acceleration exerted on the vehicle by automatically adjusting a driving force applied to road wheels;

main deceleration means for providing an increased deceleration exerted on the vehicle by automatically adjusting a braking force applied to the road wheels;

auxiliary deceleration means for producing an auxiliary braking force applied to the road wheels without utilizing the hydraulic brake system;

first arithmetic means for calculating a value of a first command signal to be sent to said acceleration means, based on a target vehicle speed and the vehicle speed detected by said detection means;

second arithmetic means for calculating a value of a second command signal to be sent to said main deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means;

third arithmetic means for calculating a value of a third command signal to be sent to said auxiliary deceleration means, based on said target vehicle speed and the vehicle speed detected by said detection means; and

decision means for switching from one of a driving-force control of said acceleration means and an auxiliary braking-force control of said auxiliary deceleration means to another, and for switching from one of said auxiliary braking-force control of said auxiliary deceleration means and a braking-force control of said main deceleration means to another;

wherein a first group of control gains used in said first arithmetic means and a third group of control gains used in said third arithmetic means are preset to provide first transition durations between said driving-force control and said auxiliary braking-force control in which said first command signal having a value greater than a first predetermined threshold and said third command signal having a value greater than a lower predetermined threshold occur concurrently, and said third group of control gains used in said third arithmetic means and a second group of control gains used in said second arithmetic means are preset to provide second transition durations between said auxiliary braking-force control and said braking-force control in which said third command signal having a value greater than an upper predetermined threshold and said second command signal having a value greater than a second predetermined threshold occur concurrently,

wherein said driving-force control is continued for said first transition durations in which the value of said first command signal is decreasingly controlled toward said first predetermined threshold and then said driving-force control is switched to said auxiliary braking-force control when said first predetermined threshold is reached, and said auxiliary braking-force control is continued for said first transition durations in which the value of said third command signal is decreasingly controlled toward said lower predetermined threshold and then said auxiliary braking-force control is switched to said driving-force control when said lower predetermined threshold is reached, and

wherein said auxiliary braking-force control is continued for said second transition durations in which the value of said third command signal is increasingly controlled toward said upper predetermined threshold and then said auxiliary braking-force control is switched to said braking-force control when said upper predetermined threshold is reached, and said braking-force control is continued for said second transition durations in which the value of said second command signal is decreasingly controlled toward said second predetermined threshold and then said braking-force control is switched to said auxiliary braking-force control when said second predetermined threshold is reached.

12. The system as claimed in claim 11, wherein each of said first and second transition durations is variable depending on a degree of a demand for acceleration or deceleration so that each of said first and second transition durations is reduced to a minimum in case of a high demand for acceleration or deceleration.