Steer-by-wire steering device capable of enhancing steering performance and reliability

• US 6,778,889 B2
• Filed: 06/28/2002
• Issued: 08/17/2004
• Est. Priority Date: 07/03/2001
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Fukushima, Noriyuki, Kato, Hironori, Sanpei, Yoshio
• Primary Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US10/185,913
• Publication Number:
  US 20030009272A1
• Time in Patent Office: 781 Days
• Field of Search: 701/41, 701/42, 180/402, 180/444, 180/446, 180/443
• US Class Current: 701/41
• CPC Class Codes: B62D 5/006 power actuated
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

The steer-by-wire steering device includes a steering wheel, an operating angle sensor which detects an operation angle of the steering wheel, an operating element actuator which applies an external force for force feedback to the steering wheel, a tire reactive force sensor, a steering actuator which applies an external force to a vehicle'"'"'s steering system, and a controller which receives output signals of the operating angle sensor and the tire reactive force sensor and controls driving of the operating element actuator and the steering actuator. A plurality of functions F₁=f(b), F₂=f(b), F₃=f(b) which use a detection signal b inputted from the tire reactive force sensor as a parameter are preliminarily stored in the controller. Then, an optimum function is selected from the plurality of preliminarily stored functions in response to a level of the detection signal b. Thereafter, a drive signal c for the operating element actuator is computed based on the selected function and the level of the inputted detection signal and then is outputted.

Claims

1. A steer-by-wire steering device comprising:

a steering operation element;

an actuator which applies an external force to the steering operation element;

a controller of the actuators; and

at least a tire reactive force sensor which detects an external force applied to a tire of the vehicle from a road surface,

wherein when a level of a detection signal detected by the tire reactive force sensor is small, reinforced external force is applied to the steering operation element by the actuator, and when the level of the detection signal detected by the tire reactive force sensor is large, attenuated external force is applied to the steering operation element by the actuator.

2. A steer-by-wire steering comprising:

a steering operation element;

an actuator which applies an external force to the steering operation element;

a controller of the actuator; and

a detector to detect a traveling condition of a vehicle including at least a tire reactive force sensor which detects an external force applied to a tire of the vehicle from a road surface,

wherein the controller stores a plurality of functions which use a detection signal inputted from the detector as a parameter therein,

the controller selects an optimum function from the plurality of functions in response to a level of the detection signal inputted from the detector,

the controller computes a control signal for the actuator based on the selected function and the level of the detection signal and outputs the control signal, and

as the detector, in addition to the tire reactive force sensor, the steering device is further provided with at least one type of sensor selected from a group of sensors including a vehicle speed sensor which detects a travelling speed of the vehicle, a torque sensor which detects torque acting on a drive shaft of the vehicle, an acceleration sensor which detects operation acceleration of the steering operation element, a temperature sensor which detects an ambient temperature, and an image pick-up sensor which detects a road surface condition.

3. A steer-by-wire steering device according to claim 2, wherein, provided that the image pick-up sensor which detects the road surface condition is provided as the detector, the function which is selected by the image pick-up sensor when the road surface is wet is a function which sets the external force applied to the steering operation element to an external force larger than an external force proportional to the level of the detection signal, and wherein the function which is selected by the image pick-up sensor when the road surface is dry is a function which sets the external force applied to the steering operation element to an external force smaller than the external force proportional to the level of the detection signal.

4. A steer-by-wire steering device according to claim 2, wherein, provided that the acceleration sensor which detects operation acceleration of the steering operation element is provided as the detector, the function which is selected when the operation acceleration detected by the acceleration sensor is at least a prescribed acceleration is a function which sets the external force applied to the steering operation element to an external force smaller than an external force proportional to the level of the detection signal.

5. A steer-by-wire steering device comprising:

a steering operation element;

an actuator which applies an external force to the steering operation element;

a controller of the actuator; and

a detector to detect a traveling condition of a vehicle including at least a tire reactive force sensor which detects an external force applied to a tire of the vehicle from a road surface,

wherein the controller stores a plurality of functions which use a detection signal inputted from the detector as a parameter therein,

the controller selects an optimum function from the plurality of functions in response to a level of the detection signal inputted from the detector,

the controller computes a control signal for the actuator based on the selected function and the level of the detection signal and outputs the control signal, and

the function which is selected when the level of the detection signal is at most a first prescribed value is a function which sets the external force applied to the steering operation element to an external force smaller than an external force proportional to the level of the detection signal, wherein the function which is selected when the level of the detection signal is at least a second prescribed value is a function which sets the external force applied to the steering operation element to an external force larger than the external force proportional to the level of the detection signal, and wherein the function which is selected when the level of the detection signal is above the first prescribed value and is below the second prescribed value is a function which sets the external force applied to the steering operation element to the external force proportional to the level of the detection signal.

6. A steer-by-wire steering device comprising:

a steering operation element;

an actuator which applies an external force to the steering operation element;

a controller of the actuator; and

a detector to detect a traveling condition of a vehicle including at least a tire reactive force sensor which detects an external force applied to a tire of the vehicle from a road surface,

wherein the controller stores a plurality of functions which use a detection signal inputted from the detector as a parameter therein,

the controller selects an optimum function from the plurality of functions in response to a level of the detection signal inputted from the detector,

the controller computes a control signal for the actuator based on the selected function and the level of the detection signal and outputs the control signal, and

the function which is selected when the level of the detection signal is at most a first prescribed value is a function which sets the external force applied to the steering operation element to an external force larger than an external force proportional to the level of the detection signal, wherein the function which is selected when the level of the detection signal is at least a second prescribed value is a function which sets the external force applied to the steering operation element to an external force smaller than the external force proportional to the level of the detection signal, and wherein the function which is selected when the level of the detection signal is above the first prescribed value and is below the second prescribed value is a function which sets the external force applied to the steering operation element to the external force proportional to the level of the detection signal.