Steering system

• US 8,340,867 B2
• Filed: 04/28/2011
• Issued: 12/25/2012
• Est. Priority Date: 02/16/2007
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Maruyama, Kouhei, Terada, Yasuhiro, Horiuchi, Yutaka, Sugitani, Nobuo, Yanagi, Takashi
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): LI, CE LI
• Application Number:
  US13/095,979
• Publication Number:
  US 20110202239A1
• Time in Patent Office: 607 Days
• Field of Search: 701/41, 701/48, 180/6.2, 180/6.24, 180/204, 180/234, 180/252, 180/412, 180/413, 180/423, 180/443, 180/445, 180/6.44, 280/5.5, 280/5.51, 280/5.52, 280/5.522
• US Class Current: 701/41
• CPC Class Codes: B62D 17/00 Means on vehicles for adjusting camber, castor, or toe-in
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 7/146 characterised by comprising means for steering by acting on the suspension system, e.g. on the mountings of the suspension arms

Abstract

A steering controller for an electric power steering device 110 includes a base signal computing part 51 for computing a base signal D_T in accordance with at least the steering torque; a damper compensation signal computing part 52 for computing a damper compensation signal in accordance with an angular velocity of an electric motor 4 or a speed of steering wheel turn; and an inertia compensation signal computing part 53 for compensating inertia and viscosity in the steering unit. The electric motor is driven by a target signal IM₁ obtained by compensating the base signal with a damper compensation signal and an inertia compensation signal, to provide a steering auxiliary force. The target signal of the auxiliary torque is compensated so that a difference between a reference self-aligning torque of front wheel in a front wheel steering vehicle and a self-aligning torque of front wheel in an all-wheel steering vehicle is provided to a driver as a responsive feeling from the steering torque.

Claims

1. A steering system comprising:

an electric power steering device which comprises a steering unit of front wheels having an electric motor configured to generate an auxiliary torque in accordance with at least a steering torque, and is configured to transmit the auxiliary torque to the steering unit;

rear wheel toe angle changers capable of changing toe angles of respective right and left rear wheels in accordance with at least a turning angle of the front wheels and a vehicle speed; and

a steering controller configured to control the electric power steering device and the toe angle changers, the steering controller including an auxiliary torque calculating unit configured to calculate a target value of the auxiliary torque and to output a target signal for driving the electric motor, wherein the auxiliary torque calculating unit compensates for a difference between a first self-aligning torque generated at the front wheels of the steering system that includes the rear wheel toe angle changers and a second self-aligning torque generated at front wheels of a hypothetical vehicle without rear wheel toe angle changers.

2. The steering system according to claim 1, wherein

the steering controller further comprises

a restoring torque calculating unit configured to calculate the first self-aligning torque based on at least a yaw rate, speed and slip angle of the vehicle and the turning angle of the front wheels,

a reference restoring torque calculating unit configured to calculate the second self-aligning torque based on at least the vehicle speed and the turning angle of the front wheels, and

a difference compensation unit configured to calculate a difference between the first self-aligning torque and the second self-aligning torque and to compensate the target signal with the difference.