Patent ID: 8165750

Claim:
A vehicle motion control device for a vehicle, the vehicle having a plurality of wheels and a driving device for driving the wheels based on a driving force/load distribution ratio, comprising: a calculating unit for obtaining, based on equations of state that describe a state of motion of the vehicle, a divergence value, which is a characteristic value that represents a tendency of vectors in a vector field, the vector field describing a state surface with axes representing state variables for the state of motion of the vehicle; a setting unit for setting a target value of the driving force/load distribution ratio for the individual wheels, such that the divergence value becomes less than a current value of the divergence value or the divergence value becomes less than or equal to zero; a driving device control unit for controlling the driving device based on the target driving force/load distribution ratio; and further comprising: a detector unit for detecting a vertical force that acts on each of the wheels; and an estimating unit for estimating a sum of driving forces transmitted to the individual wheels to obtain an estimated total driving force, and estimating a friction coefficient between the wheels and a road surface to obtain an estimated friction coefficient; wherein the calculating unit obtains nonlinear terms in a polynomial that is a sum of diagonal elements of a system matrix for equations of state, the nonlinear terms comprising a sliding angle of the front wheels and a sliding angle of the rear wheels as variables, for each of the driving force distribution ratios, based on a group of parameters including the vertical force for each of the wheels, the estimated friction coefficient, and the estimated total driving force; and wherein the setting unit sets a target value of the driving force distribution ratio based on each of the nonlinear terms obtained in the calculating unit.