In the case where drive power of a vehicle is increased, a control device starts micro-braking control for generating a braking force on at least one wheel of a front wheel and a rear wheel. During execution of the micro-braking control, the control device estimates an efficacy factor that is a factor indicating a relationship of a magnitude of the braking force to a magnitude of a pressing force generated by a friction braking system. The control device estimates the efficacy factor for the wheel, to which the braking force is applied by the micro-braking control, on the basis of a deviation between generated drive power, which is based on a required value for a power source, and actual drive power actually acting on the vehicle, and the pressing force corresponding to the wheel, to which the braking force is applied by the micro-braking control.

In the case where drive power of a vehicle is increased, a control device starts micro-braking control for generating a braking force on at least one wheel of a front wheel and a rear wheel. During execution of the micro-braking control, the control device estimates an efficacy factor that is a factor indicating a relationship of a magnitude of the braking force to a magnitude of a pressing force generated by a friction braking system. The control device estimates the efficacy factor for the wheel, to which the braking force is applied by the micro-braking control, on the basis of a deviation between generated drive power, which is based on a required value for a power source, and actual drive power actually acting on the vehicle, and the pressing force corresponding to the wheel, to which the braking force is applied by the micro-braking control.

A power supply apparatus includes a battery and a DC-DC converter converting a voltage value of the battery; a main controller determining commands required for driving and braking of a vehicle; an auxiliary controller controlling driving and braking of the vehicle when the main controller is in a function degraded status or an unfunctional status; left front, right front, left rear and right rear wheel controllers generating a braking force using an electronic mechanical brake mounted on each wheel of the vehicle; a first power line supplying power to the main controller and the left front wheel controller from a power branch point starting from the DC-DC converter; a second power line supplying power to the auxiliary controller and the right front wheel controller from the power branch point; and a third power line supplying power to the left rear and right rear wheel controllers from the power branch point.

A power supply apparatus includes a battery and a DC-DC converter converting a voltage value of the battery; a main controller determining commands required for driving and braking of a vehicle; an auxiliary controller controlling driving and braking of the vehicle when the main controller is in a function degraded status or an unfunctional status; left front, right front, left rear and right rear wheel controllers generating a braking force using an electronic mechanical brake mounted on each wheel of the vehicle; a first power line supplying power to the main controller and the left front wheel controller from a power branch point starting from the DC-DC converter; a second power line supplying power to the auxiliary controller and the right front wheel controller from the power branch point; and a third power line supplying power to the left rear and right rear wheel controllers from the power branch point.