Antiskid controller
First Claim
1. An anti-skid controller comprising:
- wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle;
vehicle body speed calculating means for calculating a vehicle body speed of the vehicle based on the wheel speed;
calculating means for calculating an average change gradient of a wheel speed over a specified period of time of one of front and rear wheels of the vehicle in which a chance in the wheel speed detected by the wheel speed detecting means within the specified period of time is smallest;
determining means for determining whether or not a change rate of a difference in wheel speeds between the front and rear wheels within the specified period of time reaches a specified value;
estimating means for estimating a friction coefficient between a road surface and the wheel, at a point in time where the change rate is found to reach the specified value or higher by the determining means based on the average change of gradient calculated immediately prior to the point in time; and
brake pressure control means for controlling brake pressure of a controlled wheel in accordance with anti-skid control reference determined by using at least the friction coefficient to prevent excess slipping of the controlled wheel based on a comparison between the vehicle body speed and a speed of the controlled wheel.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention provides an anti-skid controller capable of correctly executing ABS control by accurately estimating a road surface μ without using additional sensors. Each wheel speed is detected, and acceleration of the vehicle body in a case where a wheel speed difference between front and rear wheels exceeds a specified value is determined. In this case, by using a change rate within a specified period of time with respect to a wheel speed of one in which wheel speed changing is small as the acceleration, a road surface μ corresponding to the acceleration is determined. Corrections regarding turning, bad road travelling, road surface changing, etc. can be carried out, by determining a lateral G based on a speed difference between left and right wheels.
-
Citations
38 Claims
-
1. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; vehicle body speed calculating means for calculating a vehicle body speed of the vehicle based on the wheel speed; calculating means for calculating an average change gradient of a wheel speed over a specified period of time of one of front and rear wheels of the vehicle in which a chance in the wheel speed detected by the wheel speed detecting means within the specified period of time is smallest; determining means for determining whether or not a change rate of a difference in wheel speeds between the front and rear wheels within the specified period of time reaches a specified value; estimating means for estimating a friction coefficient between a road surface and the wheel, at a point in time where the change rate is found to reach the specified value or higher by the determining means based on the average change of gradient calculated immediately prior to the point in time; and brake pressure control means for controlling brake pressure of a controlled wheel in accordance with anti-skid control reference determined by using at least the friction coefficient to prevent excess slipping of the controlled wheel based on a comparison between the vehicle body speed and a speed of the controlled wheel. - View Dependent Claims (20)
-
-
2. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; calculating means for calculating an average change gradient of a wheel speed over a specified period of time of one of front and rear wheels of the vehicle in which a change in the wheel speed detected by the wheel speed detecting means within the specified period of time is smallest; forward and backward direction acceleration calculating means for converting the average change gradient calculated by the calculating means to a forward and backward direction acceleration of the vehicle corresponding to a road surface friction coefficient based on changes of the relative wheel speeds between the front and rear wheels detected by the wheel speed detecting means; vehicle body speed calculating means for calculating the vehicle body speed by using at least the forward and backward direction acceleration; and brake pressure control means for controlling brake pressure of a controlled wheel in order to prevent excess slipping of a controlled wheel based on comparison between the vehicle body speed and a wheel speed of the controlled wheel.
-
-
3. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; vehicle body speed calculating means for calculating a vehicle body speed of the vehicle based on the wheel speed; determining means for determining whether or not a change rate within a specified period of time with respect to a difference in speeds between the front and rear wheels reaches a specified value or higher; forward and backward direction acceleration calculating means for calculating acceleration in forward and backward directions corresponding to a road surface friction coefficient of a road surface immediately before the determining means determines that the change rate reaches the specified value or higher; estimating means for estimating a friction coefficient between the wheels and the road surface based on the forward and backward direction acceleration calculated by the forward and backward direction acceleration calculating means; and brake pressure control means for controlling brake pressure of a controlled wheel in accordance with an anti-skid control reference determined by using at least the friction coefficient in order to prevent excess slipping of the controlled wheel based on a comparison between the vehicle body speed and a wheel speed of the controlled wheel.
-
-
4. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; forward and backward direction acceleration calculating means for calculating acceleration in forward and backward directions corresponding to a road surface friction coefficient based on changes of relative wheel speeds between front and rear wheels detected by the wheel speed detecting means; lateral direction acceleration calculating means for calculating acceleration in a lateral direction of the vehicle based on wheel speeds of left and right wheels detected by the wheel speed detecting means; deceleration limit gradient calculating means for calculating a deceleration limit gradient of the vehicle based on the forward and backward direction acceleration and the lateral acceleration; vehicle body speed calculating means for calculating a vehicle body speed of the vehicle by using at least the deceleration limit gradient; and brake pressure control means for controlling brake pressure of a controlled wheel in order to prevent excess slipping of the controlled wheel based on a comparison between the vehicle body speed and a wheel speed of the controlled wheel. - View Dependent Claims (6, 7, 8, 9, 10, 11, 19)
-
-
5. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; forward and backward direction acceleration calculating means for calculating acceleration in forward and backward directions corresponding to a road surface friction coefficient based on changes of relative wheel speeds between front and rear wheels detected by the wheel speed detecting means before starting brake pressure control after braking torque is applied to the front and rear wheels of the vehicle; lateral direction acceleration calculating means for calculating acceleration in a lateral direction of the vehicle based on wheel speeds of left and right wheels detected by the wheel speed detecting means before starting brake pressure control after braking torque is applied to the front and rear wheels of the vehicle; deceleration limit gradient calculating means for calculating a deceleration limit gradient of the vehicle based on the forward and backward direction acceleration and the lateral direction acceleration; vehicle body speed calculating means for calculating a vehicle body speed by using at least the deceleration limit gradient; and brake pressure control means for controlling brake pressure of a controlled wheel in order to prevent excess slipping of a controlled wheel based on a comparison between the vehicle body speed and a wheel speed of the controlled wheel. - View Dependent Claims (12, 13, 14, 15, 16)
-
-
17. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; vehicle body speed calculating means for obtaining a vehicle body speed based on the wheel speed of each wheel; calculating means for calculating an average change gradient within a specified period of time with respect to the vehicle body speed calculated by the vehicle body speed calculating means; determining means for determining whether a change rate within a specified period of time with respect to a speed difference between a rear wheel speed and the vehicle body speed or a speed difference between a front wheel speed and the vehicle body speed reaches a specified value or higher; estimating means for estimating, when the determining means determines that the change rate reaches the specified value or higher, a friction coefficient between a road surface travelled by the vehicle and the wheels based on the average change gradient immediately before the chance rate reaches the specified value or higher; and brake pressure control means for controlling brake pressure of a controlled wheel according to an anti-skid control reference determined by using at least the friction coefficient to prevent excess slipping of the controlled wheel based on a comparison between the vehicle body speed and the speed of the controlled wheel.
-
-
18. An anti-skid controller comprising:
-
wheel speed detecting means for detecting a wheel speed of each wheel of a vehicle; vehicle body speed calculating means for obtaining a vehicle body speed based on the wheel speed of each wheel; calculating means for calculating an average change gradient within a specified period of time with respect to a vehicle body speed calculated by the vehicle body speed calculating means; determining means for determining whether either a change rate within a specified period of time with respect to a speed difference between a rear wheel speed and the vehicle body speed or a change rate within a specified period of time with respect to a speed difference between a front wheel speed and the vehicle body speed reaches a specified value or higher; estimating means for estimating, when the determining means determines that one of the change rates reaches the specified value or higher, a friction coefficient between a road surface travelled by the vehicle and the wheels based on the average change gradient calculated by the calculating means immediately before the chance rate reaches the specified value or higher; and brake pressure control means for controlling brake pressure of a controlled wheel corresponding to an anti-skid control reference determined by using at least the friction coefficient to prevent excess slipping of the controlled wheel based on a comparison between the vehicle body speed and the speed of the controlled wheel.
-
-
21. An apparatus for a vehicle comprising:
-
wheel speed detection means for detecting a wheel speed of each of front and rear wheels of a vehicle; wheel deceleration calculation means for calculating a wheel deceleration of each wheel from the detected wheel speed; speed difference calculation means for calculating a difference in the detected speeds of the front and rear wheels; timing determination means for determining, from the calculated speed difference, a timing of estimating a friction coefficient of a road surface; and estimation means for estimating the friction coefficient from the calculated wheel deceleration, and irrespective of the calculated speed difference, at the determined timing of estimating. - View Dependent Claims (22, 23, 24, 25, 29, 30, 31)
-
-
26. A method comprising the steps of:
-
detecting a wheel speed of each of front and rear wheels of a vehicle; calculating a wheel deceleration of each wheel from the detected wheel speed; calculating a difference in the detected speeds of the front and rear wheels; determining, from the calculated speed difference, a timing of estimating a friction coefficient of a road surface; and estimating the friction coefficient from the calculated wheel deceleration, and irrespective of the calculated speed difference, at the determined estimation timing. - View Dependent Claims (32)
-
-
27. A method for controlling a vehicle comprising the steps of:
-
detecting a wheel speed of each of front and rear wheels of a vehicle; calculating a wheel deceleration from the detected wheel speed; determining from the detected wheel speed a timing of estimating a friction coefficient of a road surface; estimating the friction coefficient from the calculated wheel deceleration, and irrespective of the calculated speed difference, at the determined estimation timing; and controlling an operation of the vehicle using the estimated friction coefficient. - View Dependent Claims (33)
-
-
28. A method of controlling a vehicle comprising the steps of:
-
detecting a wheel speed of each of front and rear wheels of a vehicle; calculating a wheel deceleration of each wheel from the detected wheel speed; determining which one of the wheels has the smallest change in the calculated wheel speed as compared to the change in wheel speed of the other wheels; estimating a friction coefficient from the calculated wheel deceleration of the determined one wheel; and controlling an operation of the vehicle using the estimated friction coefficient. - View Dependent Claims (34)
-
-
35. A control system for a vehicle comprising:
-
speed detecting means for detecting a speed of each of vehicle front and rear wheels; deceleration calculating means for calculating a deceleration of a vehicle body; difference calculating means for calculating a difference in the detected speeds of the front wheel and the rear wheel; timing determining means for determining a timing of estimating a road surface friction coefficient based on the calculated speed difference; and estimating means for estimating the friction coefficient based on the calculated deceleration, and irrespective of the calculated speed difference, at the timing determined by the timing determining means. - View Dependent Claims (36)
-
-
37. A control system for a vehicle comprising:
-
speed detecting means for detecting a speed of each of vehicle front and rear wheels; deceleration calculating means for calculating a deceleration of a vehicle body at every predetermined period based on the detected wheel speed; difference calculating means for detecting a difference in the detected speeds of the front wheel and the rear wheel; integration means for integrating the calculated difference for the predetermined period; comparison means for comparing the integrated difference with a predetermined reference; holding means for holding the calculated deceleration unchanged irrespective of changes in the calculated deceleration when a comparison output indicates that the integrated difference exceeds the predetermined reference; and control means for controlling a braking operation of the vehicle based on the calculated deceleration. - View Dependent Claims (38)
-
Specification