Steering control device

Patent metadata

Field	Value
Publication number	US-10131379-B2
Application number	US-201615212716-A
Country	US
Kind code	B2
Filing date	Jul 18, 2016
Priority date	Jul 24, 2015
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A steering control device restrains not only a steered angle but also a steering angle from exceeding their upper limit values. A maximum value selection circuit selects a maximum value of a target steered angle and a target steering angle as an end angle and outputs the end angle to a limiting reaction force setting circuit. The limiting reaction force setting circuit increases a limiting reaction force rapidly if the end angle becomes equal to or larger than a common threshold. A target steering angle setting circuit sets a target steering angle based on torque applied to the steering minus the limiting reaction force etc. A steering angle control circuit sets reaction torque as a manipulated variable for feedback controlling the steering angle to the target steering angle. An operation signal generation circuit outputs an operation signal to a reaction force motor so as to achieve the reaction torque.

First claim

What is claimed is:

1. A steering control device that outputs an operation signal to a steering device in which a steering angle ratio is variable, the steering angle ratio being a ratio of a steered angle of a steered wheel of a vehicle to a steering angle that is a rotation angle of a steering, the steering control device comprising:
a steering angle obtaining circuit that obtains the steering angle;
a steered angle obtaining circuit that obtains the steered angle; and
a steering limiting circuit that performs limiting control under two different conditions, the limiting control urging a user to stop operating the steering to a side where the steering angle further increases, wherein a first condition of the two different conditions occurs when the obtained steered angle reaches a steered angle threshold, and a second condition of the two different conditions occurs when the obtained steering angle reaches a steering angle threshold.

2. The steering control device according to claim 1 , further comprising:
a unit-of-measurement setting circuit that sets a unit of measurement of the steering angle obtained by the steering angle obtaining circuit and the steered angle obtained by the steered angle obtaining circuit so that the steered angle threshold and the steering angle threshold are common thresholds that are equal to each other, wherein
the steering limiting circuit performs the limiting control when a maximum value of the steered angle and the steering angle is equal to or larger than the common threshold.

3. The steering control device according to claim 1 , wherein the limiting control is control to increase a reaction force by outputting an operation signal to the steering device, the reaction force being a force against operation of the steering.

4. The steering control device according to claim 3 , wherein
the steering device includes a reaction force actuator that applies to the steering the reaction force that is the force against operation of the steering, and a steering actuator that applies a force that steers the steered wheel at least with power transmission being cut off between the steered wheel and the steering, and
the steering limiting circuit performs the control to increase the reaction force by outputting an operation signal to the reaction force actuator.

5. The steering control device according to claim 2 , wherein
the steering device includes:
a reaction force actuator that applies to the steering a reaction force that is a force against operation of the steering, and a steering actuator that applies a force that steers the steered wheel at least with power transmission being cut off between the steered wheel and the steering,

the steering limiting circuit includes:
a limiting reaction force setting circuit that sets a limiting reaction force that is a reaction force for the limiting control, to a value larger than zero if the maximum value of the steered angle and the steering angle is equal to or larger than the common threshold,
a target steering angle setting circuit that sets a target steering angle that is a target value of the steering angle, based on the set limiting reaction force,
a steering angle control circuit that operates the reaction force actuator in order to feedback control the steering angle, which is based on an output value of a steering-side sensor that detects a rotation angle of a rotary shaft that rotates in accordance with rotation of the steering, to the target steering angle,
a target steered angle setting circuit that sets a target steered angle that is a target value of the steered angle, based on the set limiting reaction force, and
a steered angle control circuit that operates the steering actuator in order to feedback control the steered angle, which is based on an output value of a steered-side sensor that detects an amount of displacement of a member that is displaced in accordance with steering of the steered wheel, to the target steered angle,

the unit-of-measurement setting circuit performs a predetermined arithmetic operation on at least one of the output value of the steered-side sensor and the output value of the steering-side sensor to produce at least one of the steering angle to be input to the steering angle control circuit and the steered angle to be input to the steered angle control circuit,
the steering angle obtaining circuit obtains the target steering angle, and
the steered angle obtaining circuit obtains the target steered angle.

6. The steering control device according to claim 3 , wherein
the steering device includes a steering actuator that steers the steered wheel, and a variable steering angle ratio actuator that changes the steering angle ratio with transmitting torque applied to the steering to the steered wheel, and
the steering limiting circuit performs the control to increase the reaction force by performing an operation to reduce an assist force that assists, with the steering actuator, steering of the steered wheel which is caused by operation of the steering.

7. The steering control device according to claim 1 , wherein
the steering is equipped with a steering-side device that rotates with the steering, and the steering-side device is connected via a signal cable to an external device that rotates relative to the steering.

Assignees

• Jtekt Corp

Inventors

• Kodera Takashi

Classifications

• B62D5/0469

  End-of-stroke control · CPC title

• B62D5/046 Primary

  Controlling the motor · CPC title

• B62D6/008 Primary

  Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications · CPC title

• B62D5/001

  Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup · CPC title