An estimating unit 7 estimates an element aij of a system matrix based
on state quantity including at least a longitudinal force Fx applied to a wheel,
a vertical force Fz applied to the wheel and a vehicle speed V. A setting unit
8 sets a target value aij regarding the element aij of the system
matrix. A processing unit 9 calculates a control value so that the estimated
element aij approaches the set target value aij. Controlling units 10
to 13 control a vehicle based on the calculated control value. Here,
the element aij is expressed by a sum of a linear term changing with linearity
of the wheel and a nonlinear term changing with nonlinearity of the wheel, and
the setting unit 8 sets the linear term of the element aij as the target
value aij.
