Developments in Programmable Analog Control Systems

The advantages of programmable control systems for gas turbine engines have been recognized for some time. In the exotic climate of the aerospace industry some progress has been achieved by the use of digital computer control. This approach, however, cannot be justifed on an economic basis for industrial or vehicular applications. A programmable analog control system is described which provides the optimum solution to the twin problems of control capability and low cost. The basic element of this system is an analog computer which is programmed from a stored digital program. This computer performs calculations directly on sensor signals in analog form to provide analog signals that can be used directly to drive the system actuators. This programmable analog computer is described in detail, and an example is given of its application to a practical gas turbine control system. The size, cost, and reliability of the final programmable analog control system is shown to be attractive.