Travel assistance method and travel assistance device

A travel assistance device comprising:

• a vehicle speed sensor configured to detect vehicle speed of a vehicle;
• a steering angle sensor configured to detect a steering angle of a steering wheel;
• a controller configured to set a required braking/driving force according to an operation amount of an accelerator pedal or a brake pedal operated by a driver, set a target value of a vehicle body slip angle, the vehicle body slip angle being an angle from a longitudinal direction of a vehicle body to a travel direction of the vehicle, as a target slip angle, based on the vehicle speed and the steering angle, estimate or detect an actual slip angle based on at least the vehicle speed and the steering angle, the actual slip angle being an actual vehicle body slip angle, and set a target braking/driving force by, when a sign of the vehicle body slip angle rotating in a turning direction of the vehicle is defined as positive and a sign of the vehicle body slip angle rotating in an opposite direction to the turning direction is defined as negative, correcting the required braking/driving force in such a manner as to increase a braking/driving force for both of a rear right wheel and a rear left wheel or reduce a braking/driving force generated on both of a front right wheel and a front left wheel when the actual slip angle is larger than the target slip angle and correcting the required braking/driving force in such a manner as to reduce a braking/driving force for both of the rear right wheel and the rear left wheel or increase a braking/driving force generated on both of the front right wheel and the front left wheel when the actual slip angle is smaller than the target slip angle;
• and
• a driving force source or a braking device configured to generate the target braking/driving force in the vehicle and control the vehicle based on the generated target braking/driving force in the vehicle.