Integrated control apparatus for vehicle
In a vehicle of a four-wheel independent steering type, an electronic control unit calculates a target yaw rate in accordance with a vehicle speed and a steering angle, and calculates a vehicle-control target value on the basis of the target yaw rate and an actual yaw rate. The electronic control unit estimates the grip factors of the individual wheels to road surface, and sets a distribution ratio for distribution of the vehicle-control target value among actuators of a steering system, a brake system, and a drive system in accordance with the estimated grip factors. The electronic control unit controls the actuators of the three systems in accordance with control instruction values determined on the basis of the vehicle-control target value and the distribution ratio.
1 . An integrated control apparatus for a vehicle comprising:
a vehicle behavioral-quantity detection device detecting a vehicle behavioral-quantity;
an operation quantity detection device detecting a quantity of driver's operation to a brake system, a drive system, and a steering system capable of independently steering individual wheels of the vehicle;
a target vehicle behavioral-quantity calculation device calculating a target vehicle behavioral-quantity in accordance with the detected vehicle behavioral-quantity and the detected operation quantity;
a vehicle-control target value calculation device calculating a vehicle-control target value on the basis of the target vehicle behavioral-quantity and the vehicle behavioral-quantity;
an estimation device for estimating grip factors of the individual wheels to road surface;
a distribution ratio setting device setting, in accordance with the grip factors of the individual wheels, a distribution ratio for distribution of the vehicle-control target value among respective actuators of at least two systems among the brake system, the drive system, and the steering system; and
a control device controlling the actuators of the at least two systems in accordance with the vehicle-control target value distributed among the actuators at the distribution ratio.
2 . An integrated control apparatus for a vehicle according to claim 1 , wherein the target vehicle behavioral-quantity calculation device calculates a target yaw rate, which serves as the target vehicle behavioral-quantity; and
the vehicle-control target value calculation device calculates the vehicle-control target value on the basis of the target yaw rate and an actual yaw rate, which serves as the vehicle behavioral-quantity.
3 . An integrated control apparatus for a vehicle according to claim 1 , wherein the drive system includes a drive force distribution device distributing drive force between front wheels and rear wheels; and the control device controls an actuator of the drive force distribution device.
4 . An integrated control apparatus for a vehicle according to claim 1 , wherein the estimation device estimates each of the grip factors on the basis of change in pneumatic trail of the corresponding wheel.
5 . An integrated control apparatus for a vehicle according to claim 1 , wherein the estimation device estimates each of the grip factors on the basis of a road surface friction allowance level of the corresponding wheel.
6 . An integrated control apparatus for a vehicle according to claim 1 , wherein the estimation device comprises:
a steering-force-index detection device detecting a steering force index including torque applied to the steering system including steering mechanisms for the individual wheels;
a self-aligning torque estimation device estimating a self-aligning torque produced by each wheel on the basis of the detected steering force index;
a wheel index estimation device estimating, on the basis of the vehicle behavioral-quantity detected by the vehicle behavioral-quantity detection device, at least one wheel index among wheel indexes including side force and slip angle of each wheel; and
a grip factor estimating device estimating the grip factor of each wheel on the basis of change in the self-aligning torque estimated by the self-aligning torque estimation device in relation to the wheel index estimated by the wheel index estimation device.
7 . An integrated control apparatus for a vehicle according to claim 6 , further comprising a reference self-aligning torque setting device for setting a reference self-aligning torque on the basis of the wheel index estimated by the wheel index estimation device and the self-aligning torque estimated by the self-aligning torque estimation device, wherein the grip factor estimating device estimates the grip factor of each wheel on the basis of results of comparison between the reference self-aligning torque set by the reference self-aligning torque setting device and the self-aligning torque estimated by the self-aligning torque estimation device.
8 . An integrated control apparatus for a vehicle according to claim 7 , wherein the reference self-aligning torque setting device sets a reference self-aligning torque characteristic which is approximated from the characteristic of the self-aligning torque estimated by the self-aligning torque estimation device in relation to the wheel index estimated by the wheel index estimation device, the reference self-aligning torque characteristic being defined as a straight line in a coordinate system and passing through the origin of the coordinate system, and sets the reference self-aligning torque on the basis of the reference self-aligning torque characteristic.