2002 Volume 45 Issue 2 Pages 479-486
A bang-bang control law is used to provide guidance for a car's steering system. The control law uses a proportional plus derivative error function which operates on the output of an observer and is suitable for embedded control of a car. The observer fuses sensor data from sensors whose reliability is inversely related to their availability. An erroneous plant model is present and is subject to nonholonomic and kinematic constraints. The sensors measure the plant with 25% systematic error at 100hertz. Internal sensors are sampled at 20hertz and have 10% error. External sensors are sampled at 5hertz and have no error. The observer performs dead reckoning during the intervals of time when the external sensors are not available. There are two internal sensors, an odometer and a steering-wheel angle meter. The odometer is used to compute a linear approximation to the speed of the plant. The steering-wheel angle meter measures the steering-wheel deflection relative to the longitudinal centerline of the plant. There are three external sensors which are used to measure the pose of the plant.