Anti-skid control system

• US 5,046,787 A
• Filed: 08/06/1990
• Issued: 09/10/1991
• Est. Priority Date: 08/04/1989
• Status: Expired due to Term

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Yoshida, Tsuyoshi, Ichikawa, Hiroyuki, Kamikado, Masaru, Okamoto, Kuniaki, Sakai, Kazunori, Sugitani, Tatsuo, Nakanishi, Nobuyasu, Kuwana, Kazutaka
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US07/563,143
• Time in Patent Office: 400 Days
• Field of Search: 303/91, 303/100, 303/102, 303/103, 303/108, 303/109, 303/97, 303/99, 364/426.02, 188/181 A, 188/182 C, 188/181 R, 180/197
• US Class Current: 303/144
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence

Abstract

The anti-skid control system is provided with wheel velocity sensors only for the driving wheels and is capable of performing the anti-skid control through its accurate estimation of the vehicle speed and proper compensatory control even when sharp braking occurs immediately upon the release of the accelerator after the occurrence of acceleration slip. The anti-skid control system is capable of starting the anti-skid control with certainty even when the braking operation is not detected because of a failure in the operation of the brake switch. The system is provided with a fluid pressure generating device, a fluid pressure controlling device, a brake operation detecting device, an acceleration detecting device, a wheel velocity detecting device, a braking force controlling device, a first estimated vehicle speed setting device and a second estimated vehicle speed setting device.

Claims

1. An anti-skid control system which is provided with wheel cylinders installed on the individual wheels, including the driving wheels, of a motor vehicle and furnishing braking force to the said wheels, a fluid pressure generating device, which supplies brake fluid pressure in accordance with the brake operation on the brake operating member to each of the said wheel cylinders, a fluid pressure controlling device set in the fluid pressure channels connected to form intercommunicating links betweenn the wheel cylinders installed on the said fluid pressure generating device and the said driving wheels, a brake operation detecting means, which detects the brake operation of the said brake operating member, an acceleration detecting means, which is installed on the said motor vehicle and detects the acceleration of the said motor vehicle, a wheel velocity detecting means, which detects the wheel velocity of the said driving wheels, and a braking force controlling means, which controls the brake fluid pressure fed to the wheel cylinders installed on the said driving wheels, driving and controlling the fluid pressure controlling device in accordance with the output signals from the said wheel velocity detecting means and the said acceleration detecting means when the said brake operation detecting means has detected any brake operation, wherein the said anti-skid control system is characterized by being equipped with a first estimated vehicle speed setting means, which sets the prescribed increase ratio to the said wheel velocity in accordance with the output signals from the said acceleration detecting means, finding a first set speed through arithmetic operations performed on the basis of the said increase ratio, and also sets the prescribed decrease ratio to the said wheel velocity, finding a second set speed through arithmetic operations performed on the basis of the said decrease ratio, and sets a first estimated vehicle speed by selecting the median value of the said second set speed, the said first set speed, and the said wheel velocity, and a second estimated vehicle speed setting means, which sets the second estimated vehicle speed, setting an increase ratio corresponding to the prescribed increase ratio for the said wheel velocity and yet smaller than the prescribed increase ratio for the said first set speed in accordance with the output signals from the acceleration detecting means mentioned above, finding a third set speed through arithmetic operations performed on the basis of the said increase ratio, also setting the prescribed decrease ratio for the said wheel velocity and finding a fourth set speed on the basis of the said decrease ratio, and selecting the median value of the said fourth set speed, the said third set speed and the said wheel velocity, and also by driving the said fluid pressure controlling device in accordance with the result of comparison with the said wheel velocity, finding the said first estimated vehicle speed through arithmetic operations performed with the said prescribed decrease ratio for the said second set speed switched to a decrease ratio smaller than that set prior to the detection of the brake operation, when the brake operation detecting means mentioned above has detected any brake operation, and yet driving the said fluid pressure controlling device in accordance with the result of comparison with the said second estimated vehicle speed and the said wheel velocity, when the said brake operation detecting means has not detected any brake operation.

2. An anti-skid control system as defined in claim 1, wherein the second estimated vehicle speed setting means mentioned above is constructed in such a manner as to set the prescribed increase ratio for the third set speed mentioned above by switching the increase ratio current at the particular moment to another increase ratio smaller than the said current ratio, in case the wheel velocity becomes larger, at least by any excess of the prescribed speed, than the first estimated vehicle speed.