Methods and systems for operating axles of a vehicle are provided. In one example, a propulsion source of a first axle is operated in a speed control mode at a first speed and a propulsion source of a second axle is operated in a speed control mode at a second speed. The propulsion sources are operated at different speeds to reduce a turning radius of a vehicle.

Methods and systems are provided for traction detection and control of a self-driving vehicle. The self-driving vehicle has drive motors that drive drive-wheels according to a drive-motor speed. Traction detection and control can be obtained by measuring the vehicle speed with a sensor such as a LiDAR or video camera, and measuring the wheel speed of the drive wheels with a sensor such as a rotary encoder. The difference between the measured vehicle speed and the measured wheel speeds can be used to determine if a loss of traction has occurred in any of the wheels. If a loss of traction is detected, then a recovery strategy can be selected from a list of recovery strategies in order to reduce the effects of the loss of traction.

In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for performing vehicle control. A computing system determines a difference between a recent rate of change and a historical rate of change of a rotating vehicle shaft of a vehicle during a vehicle race. The computing system determines that the difference between the recent rate of change of the rotating vehicle shaft and the historical rate of change of the rotating vehicle shaft satisfies a criteria for limiting vehicle power, wherein the computing system changes the criteria for limiting vehicle power during the vehicle race. The computing system sends a signal for receipt by a vehicle component of the vehicle, to cause the vehicle component to limit rotation of the rotating vehicle shaft.

An electrical passenger car, the electrical passenger car including: at least two electrically driven motors; motor control electronics; sensors; and wheels, where the wheels include a first front wheel and a first back wheel, where the first back wheel has a radius at least 20% greater than a radius of the first front wheel, and where during acceleration of the electrical passenger car, the motor control electronics receive signals from the sensors and provide traction control delivering more power to one of the at least two electrically driven motors accordingly.

Example embodiments relate to measuring rotational speeds of trailer wheels using radar. A computing device may cause a vehicle radar unit to transmit radar signals toward a wheel of trailer being pulled by the vehicle. The computing device may receive radar reflections corresponding to radar signals that reflected off the wheel and determine a rotational speed of the wheel based on the radar reflections. For instance, the computing device may identify the highest or lowest frequency in the frequency spectrum of the radar reflections and use the frequency and the wheel's radius to calculate the rotational speed of the wheel. The computing device can use rotational speed measurements for trailer wheels to monitor performance of the trailer and adjust vehicle navigation accordingly. In some instances, the computing device may determine that one of the trailer wheels requires servicing based on monitoring the rotational speeds of the trailer wheels.

The present disclosure provides an electronic stability control method for a vehicle for performing vehicular electronic stability control simply by adjusting driving force and braking power that are generated by a driving device of the vehicle without use of a driving force distributing method between front, rear, left, or right vehicle wheels. To this end, the vehicular electronic stability control method includes determining a vehicular state value indicating a driving state of a vehicle from information collected from the vehicle, comparing the determined vehicle state value with a first reference value, and controlling an operation of a driving device for generating driving force for driving the vehicle by the controller when the vehicle state value is greater than the first reference value to adjust driving force for preventing understeer or oversteer of the vehicle.

In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for performing vehicle control. Multiple target rotation rates for a vehicle shaft may be identified. A first actual rotation rate may be determined to exceed a first target rotation rate. In response, a computing system may send a first signal in order to cause a first component of a vehicle to limit the rate of rotation of the vehicle shaft. A second actual rotation rate may be determined to be below a second target rotation rate. In response, the computing system may send a second signal in order to cause the first component of the vehicle or a second component of the vehicle to increase the rate of rotation of the vehicle shaft.

An operating system for an automated vehicle includes a failure-detector and a controller. The failure-detector detects a component-failure on a host-vehicle. Examples of the component-failure include a flat-tire and engine trouble that reduces engine-power. The controller operates the host-vehicle based on a dynamic-model. The dynamic-model is varied based on the component-failure detected by the failure-detector.

A vehicle stability control device is mounted on a vehicle in which a front tire wears faster than a rear tire. An equation for calculating a target yaw rate includes a stability factor of the vehicle as a parameter, wherein the calculated target yaw rate becomes lower as the stability factor becomes larger. Understeer degree increases as the target yaw rate becomes higher than an actual yaw rate. When the understeer degree exceeds an activation threshold, vehicle stability control is activated. The vehicle stability control device further performs wear coping processing. In the wear coping processing, a wear degree parameter being wear degree of the front tire or a difference in wear degree between the front tire and the rear tire is calculated. When the wear degree parameter exceeds a wear threshold, the vehicle stability control device corrects the stability factor to be larger than a default setting value.

Techniques are described for dynamically selecting vehicles to perform road friction probing maneuvers and estimating road friction based on sensor data collected while a vehicle performs the road friction probing maneuvers. In one example, a computing system is configured to select, from a plurality of vehicles, based on an amount of elapsed time since each respective vehicle of the plurality of vehicles has performed a road friction probing maneuver, a vehicle to perform the road friction probing maneuver within a road segment of a roadway, and responsive to selecting the vehicle, output, to the vehicle, a command causing the vehicle to perform the road friction probing maneuver within the road segment.