CN-121990036-A - Steering system

Abstract

The invention provides an electric steering system with high practicability. In an electric steering system including an operation member (10) operated by a driver, a reaction force applying device (12) for applying an operation reaction force (Tc) to the operation member, a steering device (16) having a steering motor (38) as a driving source, which Is an electric motor, and controllers (40, 42) for controlling the reaction force applying device and the steering device, a controller (130) Is configured to determine an operation reaction force including a steering current dependent component (Tcb) which Is a component based on a current (Is) supplied to the steering motor, and a steering speed dependent correction component (Tcb) for reducing the steering current dependent component based on a steering speed (ω'), and to determine the steering speed dependent correction component such that the steering speed dependent correction component Is not larger than a value at a set speed when the steering speed exceeds the set speed.

Inventors

• TAKEBAYASHI RYO
• Miyake Takuya
• Henkawa
• YOSHIDA HIROSHI
• KUDO YOSHIO

Assignees

• 株式会社捷太格特

Dates

Publication Date

20260508

Application Date

20251010

Priority Date

20241105

Claims (5)

1. 1. A steering system comprising an operation member operated by a driver, a reaction force applying device for applying an operation reaction force to the operation member, a steering device for steering wheels with an electric motor as a driving source, and a controller for controlling the reaction force applying device and the steering device, wherein, The controller is configured to determine the operation reaction force including a steering current dependent component that is a component based on a current supplied to the steering motor and a steering speed dependent correction component for reducing the steering current dependent component based on a steering speed, and to determine the steering speed dependent correction component so that the steering speed dependent correction component is not greater than a value at a set speed when the steering speed exceeds the set speed.
2. 2. The steering system of claim 1, wherein the steering system comprises a steering system, The set speed is set to a speed at which the torque that can be generated by the steering motor based on the N-T characteristic is 40% to 60% of the maximum torque.
3. 3. The steering system of claim 1, wherein the steering system comprises a steering system, The controller also determines an operation reaction force including a steering acceleration-dependent correction component for reducing the steering current-dependent component based on the steering acceleration, and determines the steering acceleration-dependent correction component so that the steering acceleration-dependent correction component is not greater than a value at a set acceleration when the steering acceleration exceeds the set acceleration.
4. 4. The steering system of claim 3, wherein the steering system comprises a steering system, The set acceleration is set to a value at which it can be estimated that the steering operation is performed in the case of emergency.
5. 5. The steering system of claim 3, wherein the steering system comprises a steering system, The set acceleration is set to a value at which the operating member is operated at the set speed of 1.5Hz to 2.5 Hz.

Description

Steering system Technical Field The present invention relates to an electric power steering system mounted on a vehicle. Background An electric power steering system (hereinafter, sometimes referred to as an "electric power steering system") does not mechanically connect an operating member such as a steering wheel to a steered wheel. Therefore, the electric power steering system is provided with the reaction force applying means for applying the operation reaction force to the operation member. The operation reaction force is generally preferably set to a magnitude corresponding to the load of the steering device, that is, the steering force for steering the wheels, and is determined based on the estimated steering force. Basically, when the steering device includes a steering motor, which is an electric motor, as a driving source, a current corresponding to the steering force is supplied to the steering motor, and therefore the steering force can be estimated based on the current. Therefore, the operation reaction force may be determined based on the steering force estimated based on the supply current. However, since the steering device generates a damping force due to friction or the like on a mechanism, for example, in an electric power steering system described in the following patent documents, correction based on a steering speed is performed on a steering force estimated based on a current supplied to a steering motor. Patent document 1 Japanese patent laid-open No. 2023-8890 Depending on the characteristics of the electric motor, there is an upper limit in the supply current, and even if steering of the wheels at a high speed is required, it is not necessarily possible to supply a current corresponding to the speed. On the other hand, in the electric power steering system described in the patent document, for example, the correction based on the damping force is performed only so that the estimated steering force becomes smaller as the steering speed becomes higher. Therefore, in the above-described electric power steering system, if the steering speed is high to some extent, the actual steering force and the estimated steering force are different, and the operation reaction force does not become an appropriate force. That is, the driver is given a sense of incongruity in the steering operation. From this, it is clear that there is still a great room for improvement in determining the operation reaction force of the electric power steering system, and that the electric power steering system can be improved in practicality by some improvement. Disclosure of Invention The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric power steering system with high practicality. In order to solve the above-described problems, a steering system according to the present invention includes an operation member operated by a driver, a reaction force applying device that applies an operation reaction force to the operation member, a steering device that steers wheels, which is an electric motor that is a driving source, and a controller that controls the reaction force applying device and the steering device, wherein the controller is configured to determine the operation reaction force including a steering current dependent component that is a component based on a current supplied to the steering motor and a steering speed dependent correction component for reducing the steering current dependent component based on a steering speed, and to determine the steering speed dependent correction component so that the steering speed dependent correction component is not greater than a value at a set speed when the steering speed exceeds the set speed. According to the electric power steering system of the present invention, since the upper limit is set for the steering speed-dependent correction component, even when the steering speed increases beyond a certain level, the component of the operation reaction force that is an index of the steering force, that is, the steering force-dependent component, is contained so as to be excessively small. As a result, even if the steering speed increases beyond a certain high level, an appropriate operation reaction force can be maintained well, and the driver can be prevented from feeling uncomfortable with steering. Although described in detail later, setting the upper limit for the steering speed-dependent correction component is particularly effective, for example, in a quick steering operation for eliminating side slip (slip) of the wheels on the low μ road. [ Embodiment of the invention ] As described above, the "steering current dependent component" in the present invention is a main component that is an index of steering force, which is a force generated by the steering device to steer the wheels. In the case where the steering device is configured to move a steering rod (rack rod) connecting left and