Increasing mission reliability by using open-loop control

Increasing the mission reliability of a one-degree of freedom computer-controlled servosystem is discussed. This is accomplished by providing an acceptable degraded mode of operation that can take over functioning of the system in the event of feedback sensor failure. The degraded mode of operation used in the event of feedback failure is open-loop control. The authors successfully applied open-loop control to a large-caliber tank ammunition autoloader. The loading mechanism comprises two servosystems that use modified bang-bang controllers. Data from cycling the ramming mechanism are analyzed to determine the unknown disturbing forces, primarily friction, in the three main control phases. Experimental results are discussed