A vehicle steering device includes a steering wheel, an input shaft, an output shaft coupled to the input shaft via a torsion bar, an electric motor, a torque detector that detects a torsion bar torque applied to the torsion bar, a rotational angle detector that detects a rotational angle of the electric motor, and a microcomputer. The microcomputer is configured to estimate a driver torque applied to the steering wheel using at least (i) the torsion bar torque detected by the torque detector, (ii) the rotational angle of the electric motor detected by the rotational angle detector, and (iii) a physical model that is constructed with a torsion bar viscosity and a torsion bar rigidity, and determine whether the steering wheel is operated in a hands-on state or a hands-off state based on the estimated driver torque.

In a steering control apparatus, a basic assistance torque calculating unit calculates a basic assistance torque. A correction torque calculating unit calculates a correction torque to be added to the basic assistance torque. In the correction torque calculating unit, a returning state determining unit determines whether a steering wheel is turning or returning. A returning speed stabilization control unit calculates a returning speed stabilization torque to stabilize a returning speed of the steering wheel, as the correction torque. The returning speed stabilization control calculates the returning speed stabilization torque such as to bring a second-order time differential value of steering wheel position-related information correlated with a steering wheel position closer to zero, and such that an absolute value of the returning speed stabilization torque when the steering wheel is returning is relatively greater than that when the steering wheel is turning.

A steering control device with reduced power consumption is provided. In the case where an IG signal is turned on, a CPU disengages a clutch, and operates torque of a steered-side motor in order to control the steered angle of steered wheels to a target steered angle that matches an operation on the steering wheel through feedback control. The CPU decreases a current that flows through the steered-side motor with respect to a request by feedback control in the case where the logical product of a statement that a vehicle speed is equal to or less than a prescribed speed, a statement that the absolute value of steering torque which is input torque input to the steering wheel is equal to or less than a prescribed value, and a statement that the absolute value of a steering speed is equal to or less than a predetermined speed.

A steering control device which can suppress a degradation in the steering feel caused when a steering wheel is moved back from a steering limit is provided. A steering control device controls a steer-by-wire steering system that includes a steering-side motor that generates a steering reaction force to be applied to a steering wheel to control operation of the steering-side motor. The steering control device includes an angular speed control circuit that performs feedback control on the steering-side motor in the case where a steering angle of the steering wheel reaches a virtual rack end and the steering wheel is steered back toward the steering neutral. The feedback control is performed such that a steering speed computed on the basis of the steering angle coincides with a target steering speed that is the target value for the steering speed and that is set in accordance with the steering angle.

A controller controls a steering motor in accordance with a pinion angle command value calculated in response to a steering state. The steering motor produces a driving force to a steering operation mechanism. The controller calculates a target pinion angle in accordance with the steering state and the pinion angle command value by performing feedback control such that an actual pinion angle corresponds to the target pinion angle. The controller includes a compensation control circuit which calculates compensation amounts reflected in the pinion angle command value so as to compensate for an inertia component, a viscosity component, and a spring component of the steering operation mechanism in accordance with the target pinion angle. The compensation control circuit adds the compensation amounts to the target pinion angle so as to calculate the final target pinion angle to be used for the calculation of the pinion angle command value.

In a return control unit, a driver steering correcting unit calculates a correction amount outputted in relation to any calculation quantity in a calculation process for a return control amount, based on a steering torque and steering wheel position-related information, such that the return control amount is maintained or increased when a steering torque is applied in a returning direction towards a neutral position of a steering wheel, and the return control amount is reduced when the steering torque of which an absolute value is equal to or greater than a predetermined critical value is applied in a turning direction away from the neutral position of the steering wheel. The steering wheel position-related information is information of which a value when the steering wheel is at the neutral position is zero and the value is positive or negative based on a steering wheel position in relation to the neutral position.

A vehicle steering device includes a driver torque estimation unit that includes a driver torque estimation observer, a low-pass filter, and a hands-on/off determination unit. The driver torque estimation observer estimates driver torque applied to a steering wheel by a driver on the basis of a detected value that includes at least torsion bar torque detected by a torque sensor and the rotational angle of an electric motor detected by a rotational angle sensor. The low-pass filter performs a low-pass filtering process on the estimated driver torque. The hands-on/off determination unit determines whether in a hands-on state or a hands-off state on the basis of the driver torque after being subjected to the low-pass filtering process.

A steering controller that controls a motor to output an assist torque to steer a steering member, including a steer property calculator calculating a steer state quantity that is an index of a steering state indicating one of (i) a steer-away state, (ii) a steer-back state, or (iii) a stay-still state, an adjusted torque calculator calculating an adjusted torque based on the steer state quantity, and an instruction value calculator calculating an assist torque instruction that is an instruction value regarding a drive of the motor by using the adjusted torque. In such manner, the steer state quantity, the steer-back operation, the stay-still operation of a steering wheel, and the adjusted torque are appropriately calculated, thereby enabling an appropriate adjustment of a steering feel.

When an adjustment information input unit (1) acquires one of information of a feeling value and steering control information, a steering control information calculation unit (2) calculates data of a control characteristic graph visually representing control characteristics of steering using the acquired information. An adjustment information display unit (3) displays, on the same screen, a control characteristic graph in accordance with the data of the control characteristic graph and a feeling value operation section visually showing the feeling value.

A power steering system includes a gain module that generates an estimated driver torque, and a blending module for determining a blend value. The blend value is based at least in part on a derivative of the estimated driver torque, and the blend value is applied to a return torque of a handwheel.