A tire radius monitoring system for dynamically determining a tire effective radius for each of the wheels on a vehicle is described. The system includes a GPS sensor, a plurality of wheel speed sensors, and a controller. The controller determines, via the GPS sensor, a velocity vector related to longitudinal velocity of the vehicle. The controller determines wheel speeds for the plurality of vehicle wheels, and detects a no-wheel-slip state for the vehicle wheels and the velocity vector from the GPS sensor. The controller determines tire effective radii for the plurality of vehicle wheels based upon the velocity vector for the vehicle and the wheel speeds for the plurality of vehicle wheels during the no-wheel-slip state, and controls vehicle operation based upon the tire effective radii.

There is provided a configuration, including a storage unit that stores a theoretical driving wheel rotating speed based on a correspondence relationship with a predetermined engine speed in each gear stage of a transmission of a vehicle; gear stage detection means for detecting the gear stage when currently travelling; engine speed detection means for detecting an engine speed; driving wheel rotating speed detection means for detecting a driving wheel rotating speed; and torque control means for controlling output torque, in which the output torque is increased so that a current driving wheel rotating speed becomes close to the theoretical driving wheel rotating speed when a relative value of a calculated value which is calculated by using the detected driving wheel rotating speed with respect to a calculated value which is calculated by using the theoretical driving wheel rotating speed is equal to or greater than a first threshold value.

A vehicle body speed estimation device and a vehicle body speed estimation method are provided for estimating a vehicle body speed of a four-wheel drive vehicle from a wheel speed of each wheel of the four-wheel drive vehicle. In the vehicle body speed estimation device and a vehicle body speed estimation method, a controller determines whether a deviation of at least two of the wheel speeds among the wheel speeds is within a first prescribed range. The controller switches a method for selecting the wheel speed used for estimating the vehicle body speed between a first method and a second method when a sign of a drive torque that is applied to each of the wheels is reversed and the deviation of at least two of the wheel speeds among the wheel speeds is within the first prescribed range.

A system for measuring motion of a locomotive vehicle includes a speed sensor, a decelerometer and an onboard processing unit. The speed sensor is configured to measure wheel speed of the locomotive vehicle. The decelerometer includes a level-sensitive device configured to measure acceleration or deceleration of the locomotive vehicle as a function of a tilt from a level position. The onboard processing unit computes a current grade traversed by the locomotive vehicle prior to detection of a slip or slide condition based on a first measurement signal from the decelerometer. Upon detection of the slip or slide condition, the onboard processing unit obtains a second measurement signal from the decelerometer and filters out the current grade from the second measurement signal. The onboard processing unit determines an actual acceleration or deceleration of the locomotive vehicle during the slip or slide condition from the filtered second measurement signal from the decelerometer.

A tire radius monitoring system for dynamically determining a tire effective radius for each of the wheels on a vehicle is described. The system includes a GPS sensor, a plurality of wheel speed sensors, and a controller. The controller determines, via the GPS sensor, a velocity vector related to longitudinal velocity of the vehicle. The controller determines wheel speeds for the plurality of vehicle wheels, and detects a no-wheel-slip state for the vehicle wheels and the velocity vector from the GPS sensor. The controller determines tire effective radii for the plurality of vehicle wheels based upon the velocity vector for the vehicle and the wheel speeds for the plurality of vehicle wheels during the no-wheel-slip state, and controls vehicle operation based upon the tire effective radii.

A system for measuring motion of a locomotive vehicle includes a speed sensor, a decelerometer and an onboard processing unit. The speed sensor is configured to measure wheel speed of the locomotive vehicle. The decelerometer includes a level-sensitive device configured to measure acceleration or deceleration of the locomotive vehicle as a function of a tilt from a level position. The onboard processing unit computes a current grade traversed by the locomotive vehicle prior to detection of a slip or slide condition based on a first measurement signal from the decelerometer. Upon detection of the slip or slide condition, the onboard processing unit obtains a second measurement signal from the decelerometer and filters out the current grade from the second measurement signal. The onboard processing unit determines an actual acceleration or deceleration of the locomotive vehicle during the slip or slide condition from the filtered second measurement signal from the decelerometer.

An electronic mechanical braking method and an electronic mechanical braking apparatus are provided, and are applicable to an intelligent vehicle, a new energy vehicle, a traditional automobile, or the like. The method includes: obtaining status information of a first control unit, where the status information is used to indicate whether the first control unit works normally, and the first control unit is configured to perform braking control on a vehicle; and when the status information indicates that the first control unit cannot work normally, performing the braking control on the vehicle by using a second control unit. A plurality of control units are used to implement electronic mechanical braking control. Therefore, when one of the control units fails, the rest of the control units may further be used to continue the control, to implement redundant braking, effectively improve a braking control effect, and improve vehicle control safety.

A method for updating a vehicle reference speed for a vehicle is disclosed. The method includes increasing brake pressure to at least one wheel of the plurality of wheels and determining, via an electronic control unit, that a first wheel speed of the at least one wheel is less than a second wheel speed of another wheel of the plurality of wheels. The method also includes estimating the vehicle reference speed of the vehicle based upon the first wheel speed of the at least one wheel.

There is provided a method for estimating friction between a tire of a vehicle and a road surface, the method comprising acquiring, a front wheel axle torque, a rear wheel axle torque, a vehicle longitudinal acceleration, a vehicle pitch rate and wheel rotational velocities. The method further comprises determining a front wheel normal force and a rear wheel normal force, based on a center of gravity of the vehicle and the longitudinal acceleration; determining a longitudinal tire stiffness, jointly determining a vehicle longitudinal velocity, based on the wheel rotational velocities and vehicle longitudinal acceleration, and a vehicle pitch angle relative to the horizontal plane based on the vehicle pitch rate; and determining a friction coefficient between tires and ground based on the front and rear wheel axle torque, the front wheel normal force and the joint estimation of pitch angle and vehicle longitudinal velocity. There is also provided a system for performing the described method.

A vehicle body speed estimation device and a vehicle body speed estimation method are provided for estimating a vehicle body speed of a four-wheel drive vehicle from a wheel speed of each wheel of the four-wheel drive vehicle. In the vehicle body speed estimation device and a vehicle body speed estimation method, a controller determines whether a deviation of at least two of the wheel speeds among the wheel speeds is within a first prescribed range. The controller switches a method for selecting the wheel speed used for estimating the vehicle body speed between a first method and a second method when a sign of a drive torque that is applied to each of the wheels is reversed and the deviation of at least two of the wheel speeds among the wheel speeds is within the first prescribed range.