The vehicle steering system includes: a predicted lateral deviation fluctuation amount calculation circuitry to calculate a predicted lateral deviation fluctuation amount predicted as a lateral deviation fluctuation amount with respect to the target traveling line of the vehicle; and a steering control amount limiting circuitry to output a limited steering control amount to which the steering control amount is limited by the steering control amount limit value on the basis of a steering force and the predicted lateral deviation fluctuation amount, and in a case where the absolute value of the steering force is the same, when the absolute value of the predicted lateral deviation fluctuation amount is large, the steering control amount limiting circuitry sets the steering control amount limit value to a value larger than or equal to that when the absolute value of the predicted lateral deviation fluctuation amount is small.

A method of providing evasive steering assist (ESA) includes storing yaw rate data related to a host vehicle, wherein yaw rate data includes a yaw rate stored at each time step from an initial time step [0] to a current time step [n]. The method further includes determining whether to initiate ESA, wherein in response to a determination to initiate ESA, the method includes calculating a current position, a current heading angle, a destination position, and a destination heading angle, wherein the stored yaw rate data is utilized to determine the current heading angle and the destination heading angle. The method further includes generating an evasive steering assist (ESA) output based on the current position, the current heading angle, the destination position, and the destination heading angle.

A yaw stability control system is provided for a motor vehicle. The system includes one or more cameras, a plurality of wheel speed sensors, a yaw angle sensor, and a steering angle sensor. The system further includes an electric motor connected to a reaction wheel. The system further includes a processor and a memory including instructions such that the processor is programmed to: determine a desired yaw angle of the motor vehicle based on a video signal, speed signals, a yaw signal, and a steering signal. The processor is further programmed to generate an actuation signal associated with the desired yaw angle. The electric motor angularly rotates the reaction wheel at a predetermined angular rate in a predetermined rotational direction to produce a counter-acting torque that rotates the motor vehicle to the desired yaw angle, in response to the electric motor receiving the actuation signal from the processor.

An automatic steering system comprises a controller. The controller executes target steering angle calculation processing. The controller further calculates a learning value of lateral acceleration. The learning value is calculated based on an error of a detected value of the lateral acceleration by an acceleration sensor and an estimation value of the lateral acceleration calculated using driving speed and yaw rate. In the target steering angle calculation processing, it is judged whether the acceleration sensor is normal. If it is judged that the acceleration sensor is normal, a target steering angle is calculated by using the detected value. Otherwise, the lateral acceleration used to calculate the target steering angle is switched from the detected value to a backup value of the lateral acceleration. The backup value is calculated using the estimation value and the learning value calculated before a timing at which the acceleration sensor is judged to be abnormal.

A steering control device is configured to control a steering of a vehicle having at least one piloted actuator associated with a system for steering a wheel of the vehicle and a piloted actuator associated with a decoupled braking system at a wheel of the vehicle. The steering control device includes at least one control unit. The control unit is configured to recover at least one value characteristic of the travel of the vehicle and to issue a control instruction to the at least one piloted actuator according to the recovered value(s). The control unit includes a calculation module in which a model of a lateral dynamic behavior of the vehicle frame is implemented. At least one specific physical quantity of the lateral dynamic behavior is expressed according to the specific drifts of each set of front wheels and rear wheels of the vehicle.

Systems and methods for determining whether a vehicle is in an understeer or oversteer situation. The system includes a controller circuit coupled to an IMU and an EPS, and programmed to: calculate, for a steered first axle, an axle-based pneumatic trail for using IMU measurements and EPS signals and estimate a saturation level as a function of a distance between the axle-based pneumatic trail and zero. The system estimates, for an unsteered second axle, an axle lateral force curve with respect to a slip angle of the second axle, and a saturation level as a function of when the axle lateral force curve with respect to the slip angle transitions from positive values to negative values. The saturation level of the first axle and the second axle are integrated. The system determines that the vehicle is in an understeer or oversteer situation as a function of the integrated saturation levels.

A control device includes a processor. The processor is configured to perform a route acquisition process for acquiring route information indicating a target route of a vehicle. The processor is configured to perform a behavior optimization process for correcting, based on at least one of a plurality of state quantities indicating a behavior of the vehicle during traveling, each of a left turning command value and a right turning command value such that the behavior of the vehicle becomes a target behavior. The processor is configured to perform a locus stabilization process for correcting, based on at least one of the state quantities indicating the behavior of the vehicle during traveling, a steering command value such that the vehicle travels on the target route.

A steering control device, a steering control method, and a steering control system according to the present invention determines a rear wheel steering angle control command for returning a rear wheel steering angle to a predetermined steering angle earlier than a front wheel steering angle when steering wheel operation (that is, operation of a steering wheel) shifts from a state of additional turning to a state of cutback turning, in steering control that steers a rear wheel steering angle of a vehicle in opposite-phase with respect to a front wheel steering angle, and outputs the determined rear wheel steering angle control command to a rear wheel steering device, so that hysteresis of a yaw rate is reduced or eliminated, reducing or eliminating a sense of discomfort given to a driver.

A method of maintaining stability of a motor vehicle having a first axle, a second axle, and a steering actuator configured to steer the first axle includes determining localization and heading of the vehicle. The method also includes determining a current side-slip angle of the second axle and setting a maximum side-slip angle of the second axle using the friction coefficient at the vehicle and road surface interface. The method additionally includes predicting when the maximum side-slip angle would be exceeded using the localization, heading, and determined current side-slip angle as inputs to a linear computational model. The method also includes updating the model using the prediction of when the maximum side-slip angle would be exceeded to determine impending instability of the vehicle. Furthermore, the method includes correcting for the impending instability using the updated model and the maximum side-slip angle via modifying a steering angle of the first axle.

An integrated chassis control system includes a first sensor configured to sense a first vehicle driving in a lane adjacent to a lane in which an own vehicle is driving and to sense behavior information of the first vehicle, a second sensor configured to sense a variation in behavior of the own vehicle, a first determinator configured to determine a degree of influence of a side wind, which is predicted to occur due to the first vehicle, based on the behavior information of the first vehicle, a second determinator configured to determine a variance in abnormal behavior of the own vehicle based on information sensed by the second sensor, a first controller configured to perform a semi-active chassis system control, and a second controller configured to perform an active chassis system control.