JP-7856073-B2 - Steering control system

JP7856073B2JP 7856073 B2JP7856073 B2JP 7856073B2JP-7856073-B2

Inventors

山下敬司

Assignees

トヨタ自動車株式会社

Dates

Publication Date: 20260511
Application Date: 20230911

Claims (2)

In a steering control system mounted on a vehicle and capable of performing steering control that applies steering force to the steering wheels of the vehicle, The aforementioned means for acquiring surrounding information of the vehicle, A control determination unit detects an obstacle based on the surrounding information acquired by the surrounding information acquisition means and determines whether or not to perform steering control, An entry estimation index calculation unit calculates an entry estimation index, which is an indicator of the likelihood that another vehicle traveling in an adjacent lane adjacent to the lane in which the vehicle is traveling will enter the vehicle's lane due to the presence of the obstacle. The steering control unit, when the control determination unit determines that the steering control should be performed, performs the steering control by applying a steering force to the steering wheel in the direction opposite to the adjacent lane, according to the value of the entry estimation index calculated by the entry estimation index calculation unit. The entry estimation index calculation unit calculates the entry estimation index based on at least one of the following: the speed of the other vehicle traveling in the adjacent lane, the distance from the other vehicle to the obstacle, the number of lanes to the obstacle, and the amount of the obstacle overhanging in the lane width direction . The unit also calculates the entry estimation index as a larger value the higher the probability that the other vehicle will enter the lane in which the vehicle is traveling. The steering control unit performs steering control to apply the steering force to the steering wheel in the direction away from the adjacent lane when the value of the entry estimation index is greater than or equal to a predetermined value, and sets the steering force applied to the steering wheel in the direction away from the adjacent lane to be larger the larger the value of the entry estimation index. Furthermore, the steering control system is characterized by comprising a reaction force control unit that performs reaction force control to apply a reaction force to steering by the driver when the value of the entry estimation index is within a predetermined range that is less than the predetermined value .
In the steering control system according to claim 1, The steering control system is characterized in that the reaction force control unit sets the reaction force to be larger as the value of the entry estimation index in the predetermined range increases.

Description

This invention relates to a steering control system. In particular, this invention relates to improvements for optimizing steering control. Conventionally, steering control systems are known that apply steering force to the steering wheels to avoid contact with obstacles present in the lane in which the vehicle is traveling (hereinafter sometimes referred to as the vehicle's lane) (risk avoidance steering support), and that apply steering force to the steering wheels of the vehicle to avoid contact with other vehicles traveling in lanes adjacent to the vehicle's lane (hereinafter sometimes referred to as the adjacent lane) in response to the movement of those other vehicles. Patent Document 1 discloses a steering control system that reduces the possibility of collision with another vehicle entering the vehicle's lane in an attempt to avoid an obstacle. Specifically, when an obstacle is detected in an adjacent lane, and another vehicle is also detected in that adjacent lane, the system performs steering control that applies steering force to the vehicle's steering wheels in the opposite direction from the adjacent lane, thereby avoiding contact with the other vehicle. Japanese Patent Publication No. 2017-224163 This figure shows a schematic configuration of a vehicle equipped with a steering control system according to an embodiment.This is a functional block diagram showing the general configuration of the steering assist ECU.This diagram illustrates several examples of driving patterns in which another vehicle traveling in an adjacent lane may enter the vehicle's lane.This figure shows an example of the relationship between the entry estimation index and the control gain.This is a flowchart illustrating the steering control procedure.This diagram shows an example of the relationship between the vehicle's driving scenario and the left and right steering reaction forces when reaction force control is performed. The embodiments of the present invention will be described below with reference to the drawings. This embodiment describes the application of the present invention to a steering control system capable of steering control and reaction force control. -Outline configuration of the steering control system- Figure 1 is a diagram showing the schematic configuration of a vehicle VE equipped with the steering control system 1 according to this embodiment. The steering control system 1 according to this embodiment includes a steering device 2, an electric power steering ECU (EPS ECU) 3, and a steering assist ECU 4. Hereinafter, electric power steering will be referred to as EPS (abbreviation for Electric Power Steering) as needed. The steering system 2 includes an EPS (Electric Power Steering) device 21, which is configured as a rack-and-pinion type electric power steering system driven in response to the driver's operation of the steering wheel 22. The rack bar 21a of the EPS device 21 is connected to the knuckle arms (not shown) of the front wheels (steering wheels) 21c via tie rods 21b, 21b. The steering wheel 22 is connected to the pinion shaft 22c of the EPS device 21 via a steering shaft 22a and a universal joint 22b. In this embodiment, the EPS device 21 is a rack-coaxial electric power steering device, comprising an electric motor 21d and a conversion mechanism 21e, such as a ball screw type, which converts the rotational torque of the electric motor 21d into a force in the reciprocating direction of the rack bar 21a. The EPS device 21 generates steering force (steering assist torque) and steering reaction force by driving the rack bar 21a relative to the housing 21f. In other words, when the driver steers, the EPS device 21 generates steering force as needed to reduce the driver's steering burden, in response to a control signal (steering force control signal) transmitted from the EPS/ECU 3. Furthermore, the EPS device 21 can also generate a steering reaction force, which is a force acting in the opposite direction to the driver's operation of the steering wheel 22, in response to a control signal (steering reaction force control signal) transmitted from the EPS/ECU 3. This steering reaction force, when applied to the steering wheel 22, provides the driver with a suitable tactile feedback. Furthermore, any configuration known in the art can be used for the EPS device 21, as long as it can generate steering force and steering reaction force. For example, the EPS device 21 is not limited to a rack-coaxial type; it may also be a rack-assist type or a column-assist type electric power steering device. The steering shaft 22a is equipped with a steering angle sensor 61 for detecting the steering angle, i.e., the rotation angle of the steering shaft 22a, and a steering torque sensor 62 for detecting the steering torque. The signals indicating the steering angle detected by the steering angle sensor 61 and the signals indicating the steering torque detected by the steering torque sensor 62 are input to the EP