Antiskid control apparatus
First Claim
1. An antiskid control apparatus for a vehicle capable of switching a drive state thereof between a 2WD and a 4WD comprising:
- means for calculating an average front wheel speed and outputting a signal indicating the calculated average front wheel speed;
means for calculating an average rear wheel speed and outputting a signal indicating the calculated average rear wheel speed;
speed difference calculation means for calculating a speed difference between the average front wheel speed and the average rear wheel speed and outputting a signal indicating the calculated speed difference;
means for smoothing the speed difference and outputting a signal indicating the calculated smoothed speed difference; and
drive state decision means for deciding the drive state of the vehicle as a 4WD state if the smoothed speed difference is in a range between a predetermined upper threshold and a predetermined lower threshold and as a 2WD state if the smoothed speed difference is in a range above the predetermined upper threshold or below the predetermined lower threshold,wherein according to the drive state determined by the drive state decision means, the antiskid control state of the vehicle is switched between an antiskid control for the 2WD and an antiskid control for the 4WD, wherein the antiskid control controls the hydraulic brake pressure at each wheel in accordance with the determined drive state.
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Accused Products
Abstract
An antiskid control apparatus for vehicles having a part-time four-wheel drive mode. The antiskid control apparatus calculates an average front wheel speed and an average rear wheel speed. A difference between the average front wheel speed and average rear wheel speed is determined, and is filtered to obtain a smoothed wheel speed difference value. Based on the value of the smoothed wheel speed difference value, a determination is made whether the vehicle drive state is the two-wheel drive state or four-wheel drive state. The antiskid control of the vehicle is switched between two-wheel control and four-wheel control in accordance with the determined vehicle drive state.
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Citations
9 Claims
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1. An antiskid control apparatus for a vehicle capable of switching a drive state thereof between a 2WD and a 4WD comprising:
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means for calculating an average front wheel speed and outputting a signal indicating the calculated average front wheel speed; means for calculating an average rear wheel speed and outputting a signal indicating the calculated average rear wheel speed; speed difference calculation means for calculating a speed difference between the average front wheel speed and the average rear wheel speed and outputting a signal indicating the calculated speed difference; means for smoothing the speed difference and outputting a signal indicating the calculated smoothed speed difference; and drive state decision means for deciding the drive state of the vehicle as a 4WD state if the smoothed speed difference is in a range between a predetermined upper threshold and a predetermined lower threshold and as a 2WD state if the smoothed speed difference is in a range above the predetermined upper threshold or below the predetermined lower threshold, wherein according to the drive state determined by the drive state decision means, the antiskid control state of the vehicle is switched between an antiskid control for the 2WD and an antiskid control for the 4WD, wherein the antiskid control controls the hydraulic brake pressure at each wheel in accordance with the determined drive state. - View Dependent Claims (5, 6, 7, 8, 9)
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2. An antiskid control apparatus for a vehicle capable of switching a drive state thereof between a 2WD and a 4WD comprising:
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means for calculating an average front wheel speed and outputting a signal indicating the calculated average front wheel speed; means for calculating an average rear wheel speed and outputting a signal indicating the calculated average rear wheel speed; speed difference calculation means for calculating a speed difference between the average front wheel speed and the average rear wheel speed and outputting a signal indicating the calculated speed difference; first addition means for performing an addition of a calculation value when the speed difference between the average front wheel speed and the average rear wheel speed is positive and performing a subtraction of the calculation value when the speed difference is negative; and drive state decision means for deciding the drive state of the vehicle as a 4WD state if the calculation value is in a range between a predetermined upper threshold and a predetermined lower threshold and as a 2WD state if the calculation value is in a range above the predetermined upper threshold or below the predetermined lower threshold, wherein according to the drive state determined by the drive state decision means, the antiskid control state of the vehicle is switched between an antiskid control for the 2WD state and an antiskid control for the 4WD stated wherein the antiskid control controls the hydraulic brake pressure at each wheel in accordance with the determined drive state. - View Dependent Claims (4)
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3. An antiskid control apparatus for a vehicle capable of switching a drive state thereof between a 2WD and a 4WD comprising:
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means for calculating an average front wheel speed and outputting a signal indicating the calculated average front wheel speed; means for calculating an average rear wheel speed and outputting a signal indicating the calculated average rear wheel speed; speed difference calculation means for calculating a speed difference between the average front wheel speed and the average rear wheel speed and outputting a signal indicating the calculated the speed difference; first addition means for performing an addition of a calculation value when the speed difference between the average front wheel speed and the average rear wheel speed is positive and performing a subtraction of the calculation value when the speed difference is negative; second addition means for checking the calculation value for each of a predetermined number of control cycles, thus performing a subtraction when the calculation value is positive and performing an addition when the calculation value is negative; and drive state decision means for deciding the drive state of the vehicle as a 4WD state if the calculation value is in a range between a predetermined upper threshold and a predetermined lower threshold and as a 2WD state if the calculation value is in a range above the predetermined upper threshold or below the predetermined lower threshold, wherein according to the drive state determined by the drive state decision means, the antiskid control state of the vehicle is switched between an antiskid control for the 2WD state and an antiskid control for the 4WD state, wherein the antiskid control controls the hydraulic brake pressure at each wheel in accordance with the determined drive state.
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Specification