Development of Robust Adaptive Nonlinear Control Schemes and Testbed for Turreted Weapon Systems

The objective of this Phase I effort is to show the feasibility of significantly improving the pointing accuracy, and thereby the probability of hit, of the current weapon systems such as those on the M1A1 tanks and on the Apache helicopters. To achieve such an objective, robust adaptive nonlinear control schemes are being proposed so that hard nonlinearities such as friction, striction and backlash in the driving mechanisms can be accounted for and reduced through feedback. During the Phase I efforts, various models for such hard nonlinearities will be investigated and simulation studies will be carried out. Futhermore, recently developed algorithms by the principal investigator will be applied to compensate for hard nonlinearities such as backlash and variable friction due to aging of the parts and changes in the geometric configuration of the system. It is long understood that hard nonlinearities arising in the driving mechanism of the turreted weapon systems and in most high accuracy industrial machinery are the major causes of their performance degradation. These nonlinearities are difficult to model and therefor control. Among the approaches in handling these problems is the employment of direct drive technology, and addition of new actuators such as those that incorporates smart materials, and the use of magnetic and hydrostatic bearing. Another approach is through better modeling of these fundamental nonlinearities and thereafter more advanced control designs, we propose here to study different models for there nonlinear effects and to reduce their effects on the system performance through advanced nonlinear control designs may also be utilized for direct drive systems and systems including additional actuators such as ones based on smart materials (e.g., piezoelectrics ceramics). A testbed will be designed for evaluation purposes.