A drive force control system to increase a yaw rate greater than the yaw rate achieved by rotating a steering wheel to a maximum angle. A target yaw rate is calculated based on a steering angle of the steering wheel. A first predetermined torque and a second predetermined torque are calculated based on a difference between the target yaw rate and an actual yaw rate. When the steering angle of the steering wheel exceeds a first predetermined angle, a first correction torque to correct the first predetermined torque and a second correction torque to correct the second predetermined torque are calculated n accordance with the steering torque.

In some embodiments, a vehicle may include a frame having longitudinal axis. The vehicle may include a steering assembly having a steering input and at least one wheel. The steering assembly may be coupled to the frame and configured to steer the vehicle based on input from a steering input. The vehicle may include a first drive wheel and a second drive wheel. The vehicle may include a steering position sensor configured to detect steering input including a position of the steering input and at least one of i) a rate of change of position of steering input and ii) steering position time. The vehicle may include at least one controller configured to process a signal from the steering position sensor and, in response to the processed signal, drive the first drive wheel and the second drive wheel, the first drive wheel being driven independent of the second drive wheel.

A driving support ECU initializes a target trajectory calculation parameter at a start of LCA; calculates, based on the target trajectory calculation parameter, a target trajectory function representing a target lateral position which is a target position of an own vehicle in a lane width direction in accordance with an elapsed time from the start of LCA; calculates a target control amount based on the target trajectory function; when a steering operation by a driver has been detected, again initializes the target trajectory calculation parameter; and recalculates the target trajectory function based on the target trajectory calculation parameter.

A method for estimating a longitudinal force difference ΔFx acting on steered axle wheels of a vehicle, the method comprising obtaining data from the vehicle related to an applied steering torque M.sub.steer associated with the steered axle wheels, obtaining a scrub radius value r.sub.s associated with the steered axle wheels, and estimating the longitudinal force difference ΔFx, based on the obtained data and on the scrub radius r.sub.s, as proportional to the applied steering torque M.sub.steer and as inversely proportional to the scrub radius r.sub.s.

A vehicle lane keep control apparatus includes a steering control processor. the steering control processor is configured to, upon detection of a skid of a vehicle during control, switch modes from a lane keeping mode to a slip-handling mode, perform a steering control to allow the vehicle to have a stable attitude, and restart the lane keeping mode. The control includes setting a target route on which the vehicle is to travel, calculating a control amount for an electric power steering motor of the vehicle based on at least an amount of shifting from the target route, and causing the vehicle to travel along the target route,

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.

A driving support Electronic Control Unit (ECU) initializes a target trajectory calculation parameter at a start of Lane Change Assist Control (LCA), calculates, based on the target trajectory calculation parameter, a target trajectory function representing a target lateral position in accordance with an elapsed time from the start of LCA; and calculates a target control amount according to the target trajectory function. When it is determined that the own vehicle has crossed a boundary white line, the driving support ECU again initializes the target trajectory calculation parameter, and calculate the target trajectory function based on the target trajectory calculation parameter.

A vehicle steering intervention system and method prevents a loss of vehicle control condition or a vehicle rollover condition. The system includes a driver input torque sensor for sensing torque applied by a driver to a steering wheel, a steering angle sensor for sensing a steering angle, and a speed determination device for determining a vehicle speed. An electronic power steering unit includes an electronic processor and a memory. The electronic power steering unit determines a vehicle steering intervention threshold based on the torque sensed, the steering angle, and the vehicle speed. The electronic power steering unit predicts whether the vehicle steering intervention threshold will be exceeded within a predetermined time based on a torque gradient and/or a steering angle gradient. When the vehicle steering intervention threshold is predicted to be exceeded, the electronic power steering unit reduces a power steering assist and/or provides a counter steer force.

In some embodiments, a vehicle may include a frame having longitudinal axis. The vehicle may include a steering assembly having a steering input and at least one wheel. The steering assembly may be coupled to the frame and configured to steer the vehicle based on input from a steering input. The vehicle may include a first drive wheel and a second drive wheel. The vehicle may include a steering position sensor configured to detect steering input including a position of the steering input and at least one of i) a rate of change of position of steering input and ii) steering position time. The vehicle may include at least one controller configured to process a signal from the steering position sensor and, in response to the processed signal, drive the first drive wheel and the second drive wheel, the first drive wheel being driven independent of the second drive wheel.

Methods for ensuring road tracking up to a predefined lateral acceleration limit in a vehicle having an autonomous steering function arranged to selectively apply a steering wheel overlay torque to a normal steering assistance torque in an electrical power assisted steering system of the vehicle are provided. Such methods include acquiring the predetermined lateral acceleration limit; acquiring a signal representing a current lateral acceleration of the vehicle; comparing the predetermined lateral acceleration limit with the acquired current lateral acceleration signal to obtain a controller error; setting a torque limit for the steering wheel overlay torque; and subjecting the controller error to a proportional-integral-derivative (PID) controller, which is arranged to provide the torque limit for the steering wheel overlay torque after setting the torque limit to the initial value.