A microprocessor-based vehicle longitudinal controller

A longitudinal controller was designed to meet the following requirements: a velocityinvariant response, physical realizability, a comfortable ride, a small, vehicle-position error, short ramp lengths for merging entries, and minimal effects from disturbance inputs. A reduced-order observer was used to derive the required state feedback signals, the controller was designed to obtain a velocity-invariant response, and was realized on a microcomputer. The vehicle longitudinal dynamics were simulated on an analog computer, and the performance of the controlled system was evaluated. It was concluded that all design requirements were met. The designed digital controller is an attractive candidate for implementation, and at the very least, indicates the type of longitudinal performance one can expect from a realistically designed controller over the speed range 0-30 m/s.