Vehicle control apparatus

Patent metadata

Field	Value
Publication number	US-10933909-B2
Application number	US-201816136565-A
Country	US
Kind code	B2
Filing date	Sep 20, 2018
Priority date	Sep 27, 2017
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A control apparatus calculates an axial force deviation, which is a difference between an estimated axial force and an ideal axial force based on a target pinion angle of a pinion shaft in association with a turning operation of steered wheels. The estimated axial force is based on a state variable that reflects vehicle behavior or a road condition. The control apparatus includes a steering angle ratio change control circuit configured to calculate a target pinion angle serving as a basis for calculation of the command value. The steering angle ratio change control circuit calculates a speed increasing ratio from a steering angle ratio set based on a vehicle speed and a base gear ratio of a steering mechanism, and calculates a correction angle for a target steering angle by multiplying the speed increasing ratio and the target steering angle together.

First claim

What is claimed is:

1. A vehicle control apparatus configured to control a motor based on a command value to be calculated based on a steering condition, the motor being a source of a driving force to be applied to a steering mechanism of a vehicle, the vehicle control apparatus comprising:
a first calculation circuit configured to calculate a first component of the command value based on at least a steering torque;
a second calculation circuit configured to calculate a target rotation angle of a rotating body based on a basic drive torque, which is a total sum of the steering torque and the first component, the rotating body being configured to rotate in association with a turning operation of a steered wheel; and
a third calculation circuit configured to calculate a second component of the command value through feedback control performed so that an actual rotation angle of the rotating body equals the target rotation angle, wherein
the second calculation circuit includes:
an ideal axial force calculation circuit configured to calculate an ideal axial force based on the target rotation angle;
an estimated axial force calculation circuit configured to calculate, as an estimated axial force, an axial force applied to the steered wheel based on a state variable that reflects vehicle behavior or a road condition;
a blending calculation circuit configured to calculate a final axial force to be reflected in the basic drive torque as a reaction force component for the basic drive torque by summing up a value obtained by multiplying the ideal axial force by a blending ratio and a value obtained by multiplying the estimated axial force by a blending ratio, the blending ratios being set individually based on the state variable that reflects the vehicle behavior or the road condition or based on the steering condition; and
a subtractor configured to calculate an axial force deviation, which is a difference between the ideal axial force and the estimated axial force, and

the second calculation circuit is configured to change the target rotation angle in response to the axial force deviation.

2. The vehicle control apparatus according to claim 1 , further comprising a fourth calculation circuit configured to calculate a first correction angle for the target rotation angle so as to set a steering angle ratio, which is a ratio of a steered angle of the steered wheel to a steering angle, wherein
the fourth calculation circuit changes the first correction angle in response to the axial force deviation such that the target rotation angle is changed.

3. The vehicle control apparatus according to claim 1 , wherein
the second calculation circuit includes:
an inertia control calculation circuit configured to calculate an angular acceleration by multiplying the basic drive torque by an inverse of a moment of inertia;
a first integrator configured to calculate an angular speed by integrating the angular acceleration;
a second integrator configured to calculate the target rotation angle by integrating the angular speed; and
a viscosity control calculation circuit configured to calculate a viscosity component of the basic drive torque based on the angular speed, and

the target rotation angle is changed through at least one of an operation in which the inertia control calculation circuit changes the angular acceleration in response to the axial force deviation and an operation in which the viscosity control calculation circuit changes the viscosity component in response to the axial force deviation.

4. The vehicle control apparatus according to claim 1 , further comprising:
a fourth calculation circuit configured to calculate a first correction angle for the target rotation angle so as to set a steering angle ratio, which is a ratio of a steered angle of the steered wheel to a steering angle; and
a fifth calculation circuit configured to calculate a second correction angle for the target rotation angle that reflects the first correction angle based on a change speed of the target rotation angle, which is obtained by differentiating the target rotation angle that reflects the first correction angle, wherein
the fifth calculation circuit changes the second correction angle in response to the axial force deviation such that the target rotation angle is changed.

5. The vehicle control apparatus according to claim 1 , wherein
the steering mechanism includes a steering operation shaft configured to turn the steered wheel by applying a steering operation force generated by a steering operation motor, and
the estimated axial force is one of the following estimated axial forces:
a. a first estimated axial force calculated based on a current value of the steering operation motor;
b. a second estimated axial force calculated based on a lateral acceleration applied to the vehicle;
c. a third estimated axial force calculated based on a yaw rate, which is a speed at which the vehicle makes a turn;
d. a fourth estimated axial force obtained by summing up a value obtained by multiplying the second estimated axial force by a blending ratio and a value obtained by multiplying the third estimated axial force by a blending ratio, the blending ratios being set individually based on the vehicle behavior; and
e. a fifth estimated axial force obtained by summing up a value obtained by multiplying the first estimated axial force by a blending ratio, a value obtained by multiplying the second estimated axial force by a blending ratio, and a value obtained by multiplying the third estimated axial force by a blending ratio, the blending ratios being set individually based on the vehicle behavior.

6. The vehicle control apparatus according to claim 1 , wherein the steering mechanism includes:
a pinion shaft that serves as the rotating body and is mechanically separated from a steering wheel;
a steering operation shaft configured to turn the steered wheel in association with rotation of the pinion shaft;
a reaction motor that is a control target, the reaction motor serving as the motor and being configured to generate, based on the command value, a steering reaction force as the driving force to be applied to the steering wheel, the steering reaction force being a torque in a direction opposite to a steering direction; and
a steering operation motor that is a control target, the steering operation motor serving as the motor and being configured to generate a steering operation force for turning the steered wheel, the steering operation force being applied to the pinion shaft or the steering operation shaft.

7. The vehicle control apparatus according to toy claim 1 , wherein
the steering mechanism includes:
a pinion shaft that serves as the rotating body and is configured to operate in association with a steering wheel; and
a steering operation shaft configured to turn the steered wheel in association with rotation of the pinion shaft, and

the motor is an assist motor configured to generate a steering assist force as the driving force to be applied to the pinion shaft, the steering assist force being a torque in a direction identical to a steering direction.

8. A vehicle control apparatus configured to control a motor based on a command value to be calculated based on a steering condition, the motor being a source of a driving force to be applied to a steering mechanism of a vehicle, the vehicle control apparatus comprising:
a first calculation circuit configured to calculate a first component of the command value based on at least a steering torque;
a second calculation circuit configured to calculate a target rotation angle of a rotating body based on a basic drive torque, which is a total sum of the steering torque and the first component, the rotating body being

Assignees

• Jtekt Corp

Inventors

• Kodera Takashi
• Kita Masayuki

Classifications

• B62D6/002

  computing target steering angles for front or rear wheels (B62D7/159 takes precedence) · CPC title

• B60W30/00

  Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units · CPC title

• G01L5/22

  for measuring the force applied to control members, e.g. control members of vehicles, triggers · 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

• B62D6/00

  Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00) · CPC title