Vehicle travel state control device and vehicle travel state control method

A vehicle travel state control device comprising:

• a control force generation device configured to generate a control force in an up-down direction for suppressing vibration of a sprung portion of a vehicle between at least a pair of right and left wheels and a vehicle body portion corresponding to positions of the wheels;
• a road surface displacement-related information acquisition device configured to acquire road surface displacement-related information related to up-down displacements of a road surface;
• a roll index value acquisition device configured to acquire a roll index value that indicates a degree of roll of the sprung portion;
• and
• a control unit configured to control the control force generation device based on at least one of the road surface displacement-related information and the roll index value, wherein the control unit is configured to execute vibration suppression control, in which predicted wheel passage positions through which the wheels are predicted to pass are determined, a target vibration suppression control force for reducing vibration of the sprung portion when the wheels pass through the predicted wheel passage positions is computed based on the road surface displacement-related information, and the control force generation device is controlled based on the target vibration suppression control force when the wheels pass through the predicted wheel passage positions, and roll control, in which a target roll control force for reducing the roll of the sprung portion is computed based on the roll index value and the control force generation device is controlled based on the target roll control force;
• and
• the control unit is configured to control the control force generation device based on the target vibration suppression control force and the target roll control force which are obtained after performing at least one of a reduction correction for the target vibration suppression control force and an increase correction for the target roll control force when the vibration suppression control and the roll control are executed concurrently.