Apparatus for estimating a grip factor of at least one wheel comprising: a control unit configured to process a current slip angle of said wheel; a storage unit, within which, in a consultation table, a plurality of grip curves correlating a plurality of values of a steering parameter comprising the rack force with a plurality of values of the slip angle are recorded; along a same curve, the value of the grip factor remains unchanged; wherein the control unit is configured to cyclically estimate at least one raw value of the grip factor of said at least one wheel based on the position of a current condition within the consultation table, as a function of the current slip angle and of the current rack force.

Apparatus for estimating a grip factor of at least one wheel comprising: a control unit configured to process a current slip angle of said wheel; a storage unit, within which, in a consultation table, a plurality of grip curves correlating a plurality of values of a steering parameter comprising the rack force with a plurality of values of the slip angle are recorded; along a same curve, the value of the grip factor remains unchanged; wherein the control unit is configured to cyclically estimate at least one raw value of the grip factor of said at least one wheel based on the position of a current condition within the consultation table, as a function of the current slip angle and of the current rack force.

A vehicle speed and/or slip of a vehicle is determined. At least first and second images of a traveling surface captured by an image sensor using an optical lens are received by a processor. The images are used to determine the distance travelled by one or more pixels in first and second directions. These distances, along with the sampling rate of the image sensor, determine pixel speed in the first and second directions. The pixel speeds in the first direction, the second direction, or both, may be used to calculate the vehicle speed, a side slip angle, or a longitudinal slip. A tire speed may also be similarly determined using a second image sensor, a second optical lens, and a second processor capturing images of the tire surface. These vehicle parameters may be used for testing or operating the vehicle, including modifying vehicle behavior during operation.

A vehicle speed and/or slip of a vehicle is determined. At least first and second images of a traveling surface captured by an image sensor using an optical lens are received by a processor. The images are used to determine the distance travelled by one or more pixels in first and second directions. These distances, along with the sampling rate of the image sensor, determine pixel speed in the first and second directions. The pixel speeds in the first direction, the second direction, or both, may be used to calculate the vehicle speed, a side slip angle, or a longitudinal slip. A tire speed may also be similarly determined using a second image sensor, a second optical lens, and a second processor capturing images of the tire surface. These vehicle parameters may be used for testing or operating the vehicle, including modifying vehicle behavior during operation.

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.

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.

A vehicle body speed estimation method applied to a four-wheel drive vehicle includes: acquiring an estimated vehicle body speed based on wheel speeds or a longitudinal acceleration of the vehicle; determining whether an operation condition that includes at least a condition that the estimated vehicle body speed is higher than an operation determination speed is satisfied; performing torque limitation to reduce a torque of a portion of wheels of the vehicle when the operation condition is satisfied; determining whether a stop condition that includes a condition that the estimated vehicle body speed is lower than or equal to a stop determination speed or a condition that a duration of a state where a wheel acceleration of the portion of the wheels is higher than zero is longer than or equal to a set period of time; and stopping the torque limitation when the stop condition is satisfied.

A vehicle body speed estimation method applied to a four-wheel drive vehicle includes: acquiring an estimated vehicle body speed based on wheel speeds or a longitudinal acceleration of the vehicle; determining whether an operation condition that includes at least a condition that the estimated vehicle body speed is higher than an operation determination speed is satisfied; performing torque limitation to reduce a torque of a portion of wheels of the vehicle when the operation condition is satisfied; determining whether a stop condition that includes a condition that the estimated vehicle body speed is lower than or equal to a stop determination speed or a condition that a duration of a state where a wheel acceleration of the portion of the wheels is higher than zero is longer than or equal to a set period of time; and stopping the torque limitation when the stop condition is satisfied.

An apparatus for assistance avoidance steering is provided. The apparatus includes a processor configured to perform avoidance steering control based on Rear Wheel Steering (RWS) control when a head-on collision risk is sensed, and a storage configured to store data and an algorithm runnable by the processor. The avoidance steering control is based on the algorithm.

Dangerous driving events may be reported by detecting an occurrence of a dangerous event relating to the operation of a vehicle. A notification message of the dangerous event may be generated involving a time of occurrence of the dangerous event, a location of the dangerous event, and an event type of a plurality of event types for the dangerous event. The notification message may then be transmitted to communicate the occurrence dangerous driving event and information related to the dangerous driving event.