Nissan Motor Company Limited

Hiroyuki Furusho

Hiroshi Mouri

Masayasu Shimakage

Kenya Uenuma

Shigeki Satoh

Masaaki Nawano

A vehicle steering apparatus is comprised of an assist motor, a steering torque sensor, a steering angle sensor, and a controller. The controller has a torque producing section for estimating a virtual steering model input torque from a torque sensor detection value and a steering angle detection value, a virtual steering model of representing a desired steering characteristic which receives the virtual steering model input torque and outputs a target steering angle of a steering column shaft, and a steering angle servo for controlling an output of the assist motor so that the steering angle detection angle follows the target steering angle.

Vehicle steering apparatus

A travel road detector includes: an image pickup section producing a road image of a forward travel road in front of a driver's vehicle; a setting section setting small areas for lane marker detection; a lane marker detector detecting lane markers on both sides of a travel lane for the driver's vehicle; a first calculator calculating a travel road model parameter representing a shape of the forward travel road when a both-side lane marker detecting state is satisfied; a forward vehicle detector detecting a height of a predetermined part of a forward vehicle traveling ahead of the driver's vehicle when the both-side lane marker detecting state is present; and a second calculator calculating the travel road model parameter from information on the lane marker detection points, and information on the height of the predetermined part of the forward vehicle detected with the forward vehicle detector.

Travel road detector

A road recognition apparatus estimates road parameters of a road model equation by processing a forward road image of a vehicle. A processor sets a series of windows along a road white line (or lane marker) on the forward road image, and calculates a candidate straight line segment likely to be a white line in each window. The processor further checks an accuracy in position of a candidate white line in each window. The processor estimates the road parameters from the image coordinates of the candidate white line in each or the window higher in the accuracy, and estimates the road parameters exclusive of a vehicle lateral displacement from the gradient of candidate white line in each or the window lower in the accuracy.

Road lane marker recognition

A CCD camera or equivalent sensor is mounted on a vehicle and used to detect lane markings (usually the white or yellow painted lines) on a roadway. An electric motor coupled to a steering system is used to provide a torque input to the steering, which may either assist or oppose the steering torque from a driver. A steering controller is designed to assist the driver to maintain the vehicle lane position by holding the vehicle at a target point using a biasing torque. The controller resumes application of the biasing torque upon expiration of a predetermined period of delay time since a change from the absence of detection of lane marking to the presence of detection of lane marking after the presence of detection of lane marking that continues for a period of time less than a predetermined period of time has occurred a predetermined number of times within a predetermined period of monitoring time or the absence of detection of lane marking continues for a predetermined period of time.

Lane-following system by detection of lane marking

An apparatus for vehicle lane following in which a look ahead sensor including a CCD camera and an image processor detects a lane marking on the surface of a roadway. The image processor estimates a lateral displacement of a point at a preview distance in front of a vehicle from a target line. The target line is a line between lane markings defining a lane. An electric motor coupled to the steering mechanism is used to provide a bias (a torque input) to the steering, which may either assist or oppose to the steering torque from the driver. A steering controller is designed to assist the driver to maintain the vehicle's lane position by holding the vehicle at the target line using a biasing torque if the lane following is selected by the driver. In order to reflect the driver preference in the lane following, the controller collects a sufficient number of measures of the vehicle lateral displacement when the lane following is not selected. Based on the collected data, the controller updates the target line position. In the subsequent lane following, the driver is assisted to maintain the vehicle at this updated target line.

Lateral control of vehicle for lane following

A road curvature estimating apparatus for a vehicle includes a vehicle attitude detector which detects an attitude of the vehicle with respect to a road, a front-and-rear wheel steer-angle detector, a vehicle speed detector and a road curvature calculator. The road curvature calculator calculates a curvature of a road ahead of the vehicle on the basis of the measured vehicle attitude, the measured vehicle speed and the measured steer angles of the front and rear wheels by means of a state estimation of modern control theory. A controller executes a control of an automatic steering mechanism on the basis of the road curvature calculated.

Road curvature estimating apparatus

A vehicle steering system includes a first steering mechanism for a manual steering mode and a second steering mechanism for an automatic steering mode. A controller steers the vehicle in accordance with information on driving environment, with the second steering mechanism when the automatic mode is selected with a mode selector. There is further provided a holding device for holding the steering angle of the first steering mechanism when the automatic steering operation of the second steering mechanism is under way. In response to selection of the automatic mode, the controller performs the automatic steering control only when a sensor senses a straightforward neutral position of the first steering mechanism.

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Kanagawa, Japan

Hiroyuki Furusho