ABSTRACT
Automatic control reduces work hazards, while it contributes in reducing working hours, thus offering to working people a better quality of life. Control systems have been in existence since ancient times. A well-known ancient automatic control system is the regulator of Heron of Alexandria. This control system was designed to open the doors of a temple automatically when a fire was lit at the altar located outside the temple and to close the doors when the fire was put out. The electric power is automatically controlled as follows: the output power, along with intermediate variables or states of the system, such as oxygen, temperature, and pressure, are fed back to the controller, namely, to the computer. The sun-seeker automatic control system is composed of a telescope, two light-sensing cells, an amplifier, a motor, and gears. The automatic wheelchair is especially designed for people disabled from their neck down.
