Increasing Mission Reliability Using Open-Loop Control
Abstract
This report proposes to increase the reliability of some single- degree of freedom servo systems by providing a degraded mode of operation in the event of feedback sensor failure. Normally, the system is operated in a closed- loop feedback mode. During normal operation, information is continuously gathered on the disturbing forces encountered and their statistical variations from cycle-to-cycle. This information is used to design an open-loop controller that can take over in the event of sensor malfunction. An ideal closed-loop controller for this purpose is the modified bang-bang controller because the operating cycle for this controller is readily divided into three sections: acceleration, constant velocity, and deceleration. Disturbing forces can be estimated in the three sections. The s-mean and s-variance of the disturbing forces can then be used to design a conservative open-loop cycle. The cycle is conservative in that the target position for open-loop is less than the desired target position by an amount that yields a specified small probability of exceeding the desired target at some specified s-confidence level. The total cycle is then finished using a constant or cyclic motor force or other technique depending on the specific application. We successfully applied the developed techniques to the loading cycle of a large caliber tank ammunition autoloader.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1993
- Accession Number
- ADA271208
Entities
People
- Ronald L. Racicot
Organizations
- United States Army Armament Research, Development and Engineering Center