Vehicle steering control apparatus
First Claim
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1. A vehicle steering control apparatus comprising:
- an actuator configured to vary a steering gear ratio of a vehicle wheel steer angle of a steerable wheel to a steering wheel angle by adding an angular input of the actuator to an angular input from a steering wheel or subtracting the angular input of the actuator from the angular input from the steering wheel; and
a controller configured to control the actuator to produce an actuator torque in a steering direction at a start of a driver'"'"'s steering operation;
wherein the controller is configured to produce the actuator torque in the steering direction with the actuator in a case of a steering angle decreasing actuator operation, in which the actuator is operated to subtract a rotation angle produced by the actuator from a driver'"'"'s steering input;
wherein the controller is configured to perform a control operation to control the actuator to produce the actuator torque in a direction to reduce a deviation of an actual rotation angle of the actuator from a target rotation angle; and
wherein the controller is further configured to modify the deviation to prevent the actuator torque from being produced in an opposite direction opposite to the steering direction, by the control operation for reducing the deviation caused by a delay of the actual rotation angle with respect to the target rotation angle, which is due to internal friction in the actuator at the start of the driver'"'"'s steering operation in the case of the steering angle decreasing actuator operation.
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Abstract
A vehicle steering control apparatus includes an actuator to vary a steering gear ratio of a vehicle wheel steer angle of a steerable wheel to a steering wheel angle. A controller controls the actuator to produce an actuator torque in a steering direction at a start of a driver'"'"'s steering operation.
12 Citations
22 Claims
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1. A vehicle steering control apparatus comprising:
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an actuator configured to vary a steering gear ratio of a vehicle wheel steer angle of a steerable wheel to a steering wheel angle by adding an angular input of the actuator to an angular input from a steering wheel or subtracting the angular input of the actuator from the angular input from the steering wheel; and a controller configured to control the actuator to produce an actuator torque in a steering direction at a start of a driver'"'"'s steering operation; wherein the controller is configured to produce the actuator torque in the steering direction with the actuator in a case of a steering angle decreasing actuator operation, in which the actuator is operated to subtract a rotation angle produced by the actuator from a driver'"'"'s steering input; wherein the controller is configured to perform a control operation to control the actuator to produce the actuator torque in a direction to reduce a deviation of an actual rotation angle of the actuator from a target rotation angle; and wherein the controller is further configured to modify the deviation to prevent the actuator torque from being produced in an opposite direction opposite to the steering direction, by the control operation for reducing the deviation caused by a delay of the actual rotation angle with respect to the target rotation angle, which is due to internal friction in the actuator at the start of the driver'"'"'s steering operation in the case of the steering angle decreasing actuator operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A vehicle steering control apparatus comprising:
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an actuator provided in a mechanical steering linkage and arranged to vary a steering gear ratio of a wheel steer angle of a vehicle to a steering wheel angle; and a controller to control the actuator so as to reduce a deviation of an actual rotation angle of the actuator from a target rotation angle to achieve a desired target steering gear ratio, and to modify the deviation so as to prevent a torque from being produced by the actuator in an opposite direction opposite to a steering direction at the start of a driver'"'"'s steering operation; wherein the controller is configured; to determine the target rotation angle in one of (1) an adding direction to add a rotation an le of the actuator to a driver'"'"'s steering input and (2)a subtracting direction to subtract the rotation angle of the actuator from the driver'"'"'s steering input, in accordance with a vehicle operating condition, and to modify the deviation so as to prevent the deviation from being varied in a direction to produce an actuator torque in the opposite direction, by a delay of a rise of the actual rotation angle in the subtracting direction with respect to a rise of the target rotation angle in the subtracting direction, which is due to internal friction in the actuator acting to rotate the actuator in the steering direction. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A vehicle steering control method comprising:
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producing a control signal using a controller, to control an actuator to vary a steering gear ratio of a vehicle wheel steer angle of a steerable wheel to a steering wheel angle; and modifying the control signal using the controller, so as to prevent a torque from being produced by the actuator in an opposite direction opposite to a steering direction at a start of a driver'"'"'s steering operation; wherein the actuator is controlled to reduce a deviation of an actual rotation angle of the actuator from a target rotation angle, and wherein the deviation is modified using the controller, to prevent the deviation from being varied in a direction to produce an actuator torque in the opposite direction opposite to the steering direction, by a delay of the actual rotation angle with respect to the target rotation angle due to internal friction in the actuator acting to rotate the actuator in the steering direction at the start of the driver'"'"'s steering operation.
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Specification