Four-wheel steering system

• US 4,865,146 A
• Filed: 10/21/1988
• Issued: 09/12/1989
• Est. Priority Date: 10/23/1987
• Status: Expired due to Fees

• Current Assignee: Jidosha Kiki Co., Ltd.
• Original Assignee: Jidosha Kiki Co., Ltd.
• Inventors: Ohe, Takeshi
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): McGiehan, Donn
• Application Number:
  US07/261,035
• Time in Patent Office: 326 Days
• Field of Search: 180/140, 180/142, 180/148, 180/79.1, 280/91, 364/424.01
• US Class Current: 180/413
• CPC Class Codes: B62D 7/159 characterised by computing methods or stabilisation processes or systems, e.g. responding to yaw rate, lateral wind, load, road condition

Abstract

A four-wheel steering system includes a torque sensor, a first steering angle sensor, a vehicle speed sensor, a second steering angle sensor, a first DC motor, a second DC motor, and a controller. The torque sensor outputs a front-wheel steering force signal. The first steering angle sensor outputs a front-wheel steering angle signal. The vehicle speed sensor outputs a vehicle speed signal. The second steering angle sensor outputs a rear-wheel steering angle signal. The first DC motor supplies a torque to a front-wheel steering system. The second DC motor supplies a torque to a rear-wheel steering system. The controller outputs a rear-wheel steering force signal by detecting a current supplied to the second DC motor, and determines a control target value by receiving the front- and rear-wheel steering force signals and the front- and rear-wheel angle signals, and the vehicle speed signal.

Claims

1. A four-wheel steering system comprising:

a torque sensor for detecting a front-wheel steering force and outputting a first steering force signal;

a first steering angle sensor for detecting a front-wheel steering angle and outputting a first steering angle signal;

a vehicle speed sensor for detecting a vehicle speed and outputting a vehicle speed signal;

a second steering angle sensor for detecting a rear-wheel steering angle and outputting a second steering angle signal;

a first DC motor for supplying a torque to a front-wheel steering system;

a second DC motor for supplying a torque to a rear-wheel steering system; and

a controller for detecting a current supplied to said second DC motor and generating a second steering force signal representing a rear-wheel steering force, and receiving the first steering force signal, the first and second steering angle signals, and the vehicle speed signal and determining a control target value.

2. A system according to claim 1, wherein the control target value is a steering angle ratio determined by front-wheel steering angle and force signals, and a vehicle speed signal.

3. A system according to claim 1, wherein the control target value is defined by the front-wheel steering force and a steering angle ratio, both of which are determined by the first steering angle and force signals, the second steering angle and force signals, and the vehicle speed signal.