A method for maintaining a marine vessel propelled by a marine propulsion device in a selected position includes determining a current global position of the marine vessel and receiving a signal command to maintain the current global position. The current global position is stored as a target global position in response to receiving the signal command. A subsequent global position of the marine vessel is determined and a position error difference between the subsequent global position and the target global position is determined. The method includes determining marine vessel movements required to minimize the position error difference, and causing the marine propulsion device to produce a thrust having a magnitude, a direction, and an angle calculated to result in achievement of the required marine vessel movements. At least one of timing and frequency of discontinuity of thrust production is controlled while the position error difference is minimized.

A vehicle steering device includes an electric motor applying a steering force to a vehicle turning mechanism, a first setting portion setting a target assist torque in accordance with a steering torque, a second setting portion setting an angle controlling target torque for bringing an angular deviation between a target steering angle and an actual steering angle close to zero, a restriction processing portion restricting the angle controlling target torque set by the second setting portion, a first calculating portion calculating a target automatic steering torque using the angle controlling target torque after the restriction process by the restriction processing portion, and second calculating portions performing weighted addition of the target automatic steering torque and the target assist torque in accordance with a value that changes in accordance with a driver input to calculate a target motor torque that is a electric motor target motor torque value.

A present steering position of a manually actuatable steering unit of the motor vehicle is determined based on sensor data. A steering command is generated based on the present steering position of the steering unit. Then, based on sensor-detected present vehicle dynamics data, it is determined whether the motor vehicle is in a straight-ahead running situation during driving operation. It is determined whether, during the straight-ahead running situation of the motor vehicle, the present steering position of the steering unit deviates from a straight-ahead running position of the steering unit for at least one of a specified time period and a specified traveling distance of the motor vehicle. A compensation steering command is generated based on the determined deviation of the present steering position of the steering unit from the straight-ahead running position. A corrected steering command is generated based on combining the compensation steering command with the steering command.

Disclosed herein are Motor-Driven Power Steering (MDPS) and a control method thereof. The MDPS includes an information detection unit configured to detect information about the behavior of a vehicle; and a controller configured to receive the information about the behavior of the vehicle from the information detection unit, to determine whether the vehicle is accelerating and whether the vehicle pulls to one side, and to generate compensation torque and drive a driving motor based thereon.

A steering control system includes a steering-motor for turning wheels, a reaction-force-motor for applying a reaction torque to a steering of the vehicle, and a controller. The controller calculates a turning angle based on a first-characteristic representing a relationship of the turning angle to a steering angle, and calculates a reaction torque based on a second-characteristic representing a relationship of a reaction torque to the steering angle. The controller changes the first-characteristic from a characteristic corresponding to a first-state to a characteristic corresponding to a second-state in response to a change in the state of the vehicle from the first-state to the second-state. The controller maintains the second-characteristic at the characteristic corresponding to the first-state when the state of the vehicle changes from the first-state to the second-state in the case where the steering angle is steered to a steering limit corresponding to an upper limit of the turning angle.

A method is provided for steering control of a vehicle by using lateral velocity of two know points (or lateral velocity of one known point and yaw rate), longitudinal velocity and steer angle information. These factors are used to calculate a target steer angle based on the track angle based on yaw decomposition to thus adjust a current steer angle of the vehicle based on the target steer angle.

The steering control apparatus determines whether or not a deviation degree of a current traveling route of a vehicle with respect to a target traveling route is equal to or more than a predetermined threshold, when steering control is switched from manual steering control to automatic steering control. In the automatic steering control, a command steering angle is calculated so that a difference between a real traveling route of the vehicle and the target traveling route is eliminated. However, when the deviation degree is equal to or more than the predetermined threshold, the steering control apparatus recalculates the command steering angle used in the command steering angle tracking control based on a steering angle at the time of starting the automatic steering control and the command steering angle so that a real steering angle after switching to the automatic steering control changes gradually to the command steering angle.

A vehicle steering device includes a first setting portion 41 that sets a target assist torque in accordance with a steering torque, a second setting portion 42 that sets an angle controlling target torque for bringing an angular deviation between a target steering angle and an actual steering angle close to zero, an estimator that estimates a compensation object 43 load with respect to the angle controlling target torque, a first calculating portion 44 that calculates a target automatic steering torque based on the angle controlling target torque set by the second setting portion and the compensation object load estimated by the estimator, and a second calculating portion 44 that performs weighted addition of the target automatic steering torque and the target assist torque in accordance with a value that changes in accordance with a driver input to calculate a target motor torque that is a target value of a motor torque of the electric motor.

A present steering position of a manually actuatable steering unit of the motor vehicle is determined based on sensor data. A steering command is generated based on the present steering position of the steering unit. Then, based on sensor-detected present vehicle dynamics data, it is determined whether the motor vehicle is in a straight-ahead running situation during driving operation. It is determined whether, during the straight-ahead running situation of the motor vehicle, the present steering position of the steering unit deviates from a straight-ahead running position of the steering unit for at least one of a specified time period and a specified traveling distance of the motor vehicle. A compensation steering command is generated based on the determined deviation of the present steering position of the steering unit from the straight-ahead running position. A corrected steering command is generated based on combining the compensation steering command with the steering command.

An EPS controller reduces a turning angle of front wheels when it is determined that a normative yaw rate is larger than an actual yaw rate.