Modern automobiles have a variety of automated control systems, such as vehicle brake control. Anti-lock brake systems are well-known examples of automated vehicle brake control. A controller may determine when any one or more of the vehicle wheels is rotating at a rate that indicates the wheel is slipping and responsively controls the brake force to reduce such slipping. Anti-lock or similar brake control strategies have been incorporated into various automated vehicle stability control systems.
Some vehicles are designed to be capable of driving over various terrains. Such all-terrain vehicles may be driven over rough or very steeply inclined surfaces, for example. One automated control strategy provided on some such vehicles is known as hill descent control (HDC). With some HDC systems, a driver is able to select a desired speed for descending a hill. The automated HDC typically includes controlling the brakes to attempt to maintain the vehicle speed at or below the desired speed indicated by the driver.
One improvement to HDC is disclosed in U.S. Pat. No. 7,762,633. That patent describes an approach to controlling the vehicle brakes to attempt to allow the vehicle to accelerate from a standstill to a desired hill descent speed in a controlled manner depending on the slope of the hill. Such brake control is intended to avoid driver discomfort or lack of confidence in the HDC feature, either of which may be associated with an unexpectedly rapid or uneven acceleration of the vehicle.