| CPC B60W 30/18109 (2013.01) [B60W 40/101 (2013.01); B60W 40/107 (2013.01)] | 10 Claims |
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1. A vehicle body speed estimation method applied to a four-wheel drive vehicle, the vehicle body speed estimation method comprising:
acquiring an estimated vehicle body speed based on wheel speeds or a longitudinal acceleration of the vehicle;
determining whether an operation condition that includes at least a condition that the estimated vehicle body speed is higher than an operation determination speed is satisfied;
performing torque limitation to reduce a torque of a portion of wheels of the vehicle when the operation condition is satisfied;
determining whether a stop condition that includes a condition that the estimated vehicle body speed is lower than or equal to a stop determination speed or a condition that a duration of a state where a wheel acceleration of the portion of the wheels is higher than zero is longer than or equal to a set period of time;
stopping the torque limitation when the stop condition is satisfied;
acquiring a first estimated vehicle body speed based on the wheel speeds;
calculating a second estimated vehicle body speed based on an integral of a sum of the longitudinal acceleration and an offset;
determining whether a slip determination condition that includes at least a condition that the first estimated vehicle body speed is higher than the second estimated vehicle body speed is satisfied;
setting the first estimated vehicle body speed for the estimated vehicle body speed when the slip determination condition is not satisfied; and
setting the second estimated vehicle body speed for the estimated vehicle body speed when the slip determination condition is not satisfied.
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