Abstract: In a steering apparatus, in accordance with a grip limit control process (30b?), it is determined whether or not a grip degree ? estimated by a grip degree estimation arithmetically operating process (30a) is less than a predetermined grip degree (??), and in the case that it is determined that an estimated grip degree (?) is less than the predetermined grip degree (??), the process applies such a feeling that a steering operation by a steering wheel suddenly becomes light to a driver, by suddenly increasing an assist quantity by a motor (M), thereby notifying the driver of the matter that the grip degree of a steered wheel is close to a limit. Therefore, it is possible to transmit to the driver a probability that a side slip is generated by further turning the steering wheel 21 in the same direction as the current direction, thereby calling the driver's attention for steering.

Abstract: In accordance with a vehicle motion control apparatus, a steering angle (?h) of a steering wheel is determined on the basis of a rotation angle (?pm) of an assist motor (24m) detected by a rotation angle sensor (24s) and a rotation angle (?vm) of a gear ratio variable motor (32m) detected by a rotation angle sensor (32s), and a VGRS control process (40a) of a gear ratio variable mechanism is executed on the basis of the determined steering angle (?h). Accordingly, since the steering angle (?h) of the steering wheel is determined on the basis of the rotation angle (?vm) used for the VGRS control process (40a) of the gear ratio variable mechanism and the rotation angle (?pm) used for an EPS control process (30a) of an EPS actuator, it is possible to obtain the steering angle (?h) of the steering wheel without a steering angle sensor. Therefore, it is possible to reduce the number of the parts of a vehicle motion control apparatus.

Abstract: In accordance with a steering apparatus (20), a grip state between a ground surface on which a steered wheel is grounded and the steered wheel is estimated by a grip degree estimation arithmetically operating process (30a) which is arithmetically operated by AFS_ECU (30), and VGRS target angle is set such that a steering gear ratio is increased in the case that the grip degree gets close to a grip limit on the basis of an estimated grip state, in accordance with a grip degree vs gear ratio map (30b). Accordingly, since it is possible to estimate the grip degree which is changed in correspondence to a magnitude of the road surface it, for example, in the case that the steered wheel gets close to the grip limit, it is possible to increase the steering gear ratio so as to set large even at a time when the vehicle runs at the low speed.

Abstract: In accordance with a vehicle motion control apparatus, a steering angle (?h) of a steering wheel is determined on the basis of a rotation angle (?pm) of an assist motor (24m) detected by a rotation angle sensor (24s) and a rotation angle (?vm) of a gear ratio variable motor (32m) detected by a rotation angle sensor (32s), and a VGRS control process (40a) of a gear ratio variable mechanism is executed on the basis of the determined steering angle (?h). Accordingly, since the steering angle (?h) of the steering wheel is determined on the basis of the rotation angle (?vm) used for the VGRS control process (40a) of the gear ratio variable mechanism and the rotation angle (?pm) used for an EPS control process (30a) of an EPS actuator, it is possible to obtain the steering angle (?h) of the steering wheel without a steering angle sensor. Therefore, it is possible to reduce the number of the parts of a vehicle motion control apparatus.

Abstract: In a steering apparatus, in accordance with a grip limit control process (30b?), it is determined whether or not a grip degree ? estimated by a grip degree estimation arithmetically operating process (30a) is less than a predetermined grip degree (??), and in the case that it is determined that an estimated grip degree (?) is less than the predetermined grip degree (??), the process applies such a feeling that a steering operation by a steering wheel suddenly becomes light to a driver, by suddenly increasing an assist quantity by a motor (M), thereby notifying the driver of the matter that the grip degree of a steered wheel is close to a limit. Therefore, it is possible to transmit to the driver a probability that a side slip is generated by further turning the steering wheel 21 in the same direction as the current direction, thereby calling the driver's attention for steering.