SPEED CONTROL SYSTEM FOR A VEHICLE

A vehicle speed control system is provided to maintain the vehicle speed at a target value. The control system includes a target vehicle speed determining section, a section for calculating a driving torque necessary to drive the vehicle at the target vehicle speed, a section for calculating a target engine rotational speed and an engine load torque and a section for calculating a control amount for controlling an opening of the throttle valve of the engine. The driving torque calculating section and the control amount calculating section are designed based on linear control theory on physical models describing the behavior of the vehicle and the engine, respectively, thereby improving the responsiveness of the control system compared to conventional PID control. The design of the control system is characterized by separate sections which reduces designing labor and which facilitate standardization of every section.