Vehicle motion control device and method

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 force detection unit for detecting forces that act on the wheels;
• a target distribution ratio calculating unit for obtaining nonlinear terms by use of a group of parameters including the forces detected by the force detection unit, and obtaining a target value of the driving force/load distribution ratio so as to minimize the nonlinear terms, the nonlinear terms being included in elements of a system matrix of equations of state that describe a state of motion of the vehicle, each of the elements of the system matrix of the equations of state being expressed as a sum of linear terms and the nonlinear terms;
• the linear terms being independent of the forces detected by the force detection unit and independent of the driving force/load distribution ratio;
• and the nonlinear terms being dependent on the forces detected by the force detection unit and dependent on the driving force/load distribution ratio;
• and
• a driving device control unit for controlling the driving device based on the target value of the driving force/load distribution ratio;
• wherein the driving device control unit compares a current value of the driving force/load distribution ratio to the target value of the driving force/load distribution ratio, and, based on results, determines whether or not to set the target value of the driving force/load distribution ratio into the driving device;
• wherein
• if an absolute value of the nonlinear term with the target value of the driving force/load distribution ratio is smaller than that of the nonlinear term with the current value of the driving force/load distribution ratio the driving device control unit sets the target value of the driving force/load distribution ratio into the driving device, and
• if said absolute value of the nonlinear term with the target value of the driving force/load distribution ratio is equal to or greater than that of the nonlinear term with the current value, then the driving device control unit does not set the target value into the driving device.