A vehicle system includes an engine driving a vehicle, a front wheel and a rear wheel, a suspension device with an attachment portion to a vehicle body which is located at a higher level than a center axis of the rear wheel, an electromagnetic coupling to distribute a torque of the engine to the front wheel and the rear wheel, a steering wheel to be operated by a driver, a steering angle sensor to detect a steering angle corresponding to operation of the steering wheel, and a controller to control the engine and the electromagnetic coupling. The controller is configured to control the electromagnetic coupling such that the torque distributed to the rear wheel is decreased in accordance with a returning operation of the steering wheel which is detected by the steering angle sensor.

When braking of the electric vehicle is performed, the braking is controlled based on a target braking split ratio which is a target value of the ratio of the braking force that is applied to the rear wheels to a total braking force that is applied to the front and rear wheels. In this case, an initial value of the target braking split ratio is set to a value within an allowable range about a transmission split ratio when braking of the electric vehicle is started while the electric vehicle is being braked by the motor, the transmission split ratio being the ratio of a braking force that is transmitted from a drive shaft to the rear wheels via a driving force split device to a total braking force that is transmitted from the drive shaft to the front and rear wheels via the driving force split device.

When braking of the electric vehicle is performed, the braking is controlled based on a target braking split ratio which is a target value of the ratio of the braking force that is applied to the rear wheels to a total braking force that is applied to the front and rear wheels. In this case, an initial value of the target braking split ratio is set to a value within an allowable range about a transmission split ratio when braking of the electric vehicle is started while the electric vehicle is being braked by the motor, the transmission split ratio being the ratio of a braking force that is transmitted from a drive shaft to the rear wheels via a driving force split device to a total braking force that is transmitted from the drive shaft to the front and rear wheels via the driving force split device.

Provided is a control apparatus, a control method, and a control system for an electric vehicle that can prevent or reduce an unnecessary torque fluctuation on a wheel not targeted for slip control. A control apparatus for an electric vehicle limits a torque to be output to a non-target wheel according to a torque output to a target wheel after target wheel slip control is started, and updates a limit value of the torque to be output to the non-target wheel when a fluctuation range of the torque output to the target wheel falls within a predetermined range during the limitation.

Provided is a control apparatus, a control method, and a control system for an electric vehicle that can prevent or reduce an unnecessary torque fluctuation on a wheel not targeted for slip control. A control apparatus for an electric vehicle limits a torque to be output to a non-target wheel according to a torque output to a target wheel after target wheel slip control is started, and updates a limit value of the torque to be output to the non-target wheel when a fluctuation range of the torque output to the target wheel falls within a predetermined range during the limitation.

A method for updating a vehicle reference speed for a vehicle is disclosed. The method includes increasing brake pressure to at least one wheel of the plurality of wheels and determining, via an electronic control unit, that a first wheel speed of the at least one wheel is less than a second wheel speed of another wheel of the plurality of wheels. The method also includes estimating the vehicle reference speed of the vehicle based upon the first wheel speed of the at least one wheel.

A method of controlling braking of a vehicle is provided. When a disconnector is disconnected and an auxiliary drive wheel is separated from a driving system, vehicle braking is performed with regenerative braking by a primary drive wheel motor during braking. Subsequently, the disconnector is connected based on a vehicle stability state, and then, braking is performed simultaneously on the auxiliary drive wheel and a primary drive wheel.

A method of controlling braking of a vehicle is provided. When a disconnector is disconnected and an auxiliary drive wheel is separated from a driving system, vehicle braking is performed with regenerative braking by a primary drive wheel motor during braking. Subsequently, the disconnector is connected based on a vehicle stability state, and then, braking is performed simultaneously on the auxiliary drive wheel and a primary drive wheel.

A method for determining a contact force on a utility vehicle includes providing the utility vehicle with a first wheel axle and a second wheel axle, determining a drive slip of the second wheel axle, and a road surface-specific determination data set associated with a traction coefficient in dependence on the drive slip, and determining the contact force on the second wheel axle based on the drive slip of the second wheel axle and the road surface-specific determination data set.

A method for determining a contact force on a utility vehicle includes providing the utility vehicle with a first wheel axle and a second wheel axle, determining a drive slip of the second wheel axle, and a road surface-specific determination data set associated with a traction coefficient in dependence on the drive slip, and determining the contact force on the second wheel axle based on the drive slip of the second wheel axle and the road surface-specific determination data set.