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Wireless technology has gained much interestin industrial automation due to its flexibility, mobility, easeof installation, and lower cost. Wireless systems, in general,require additional and different engineering and maintenancetasks, for example cryptographic key management for security.The pace of application in process control has been impeded,however, by concern about the risks involved in incorporatingwireless paths in feedback loops and making the accommoda-tions necessary for reliable control. The issue is that there areconflicts between maintaining control loop performance andthe usual objectives in managing a wireless sensor network.In this paper, we take a holistic approach that addressessafety, reliability and security in two primary aspects: com-munication and control; thus we hope to contribute a morecomplete roadmap for developing safe and secure wireless net-worked control systems. This proposed framework representsa synthesis of two formerly separate bodies of research, oneprimarily focussed on communication requirements for safetyand security and the other on safe and reliable controls.

The objective of this program is to develop a software tool which support rapid control law synthesis and analysis for aircraft flight, propulsion, and structural control systems. Payoff are fast, efficient data transfer between these disciplines for supporting integrated control law development and improving aircraft performance.

This report presents new methodologies and results in the study of aircraft stability and control, including detailed consideration of piloting effects on the aircraft's motion. The potential for departure (i.e., loss of control) in transonic and supersonic flight is addressed using linear, time- invariant dynamic models which incorporate longitudinal-lateral-directional coupling. A method for designing departure-prevention command augmentation systems (DPCAS) is developed and is applied to the subsonic model of the F-14A aircraft. This design technique can provide excellent flying qualities for the aircraft throughout its flight envelope. A multivariable limit cycle analysis technique (MULCAT) is used to predict possible self-induced nonlinear oscillations, and the results of this prediction are evaluated using a direct simulation of the nonlinear dynamic model.

The Covariance Analysis Describing Function Technique (CADET) -- a technique for the efficient direct statistical analysis of nonlinear systems with random inputs -- is extended in scope to permit the study of a complicated, highly nonlinear model for a tactical missile homing guidance system. Numerous parameter sensitivity studies are performed with selected cases verified by the monte carlo method. The validity of the assumptions underlying the CADET theory is investigated and the impact of possible errors in these assumptions on the accuracy of CADET is assessed. In every realistic situation studied, CADET provided accurate missile performance projections with a small fraction of the computer time required for a comparably reliable monte carlo analysis.

This report deals with several techniques for passive ranging, i.e., the estimation of target range from noisy measurements of bearing or line-of- sight angle alone. The type of engagement treated in this investigation involves a maneuvering surface target and a missile without an altimeter. The missile approaches the target along a trajectory that is characterized by a low- altitude cruise phase followed by a terminal pitch-up maneuver. Several modified Kalman filter-like algorithms are applied to this nonlinear filtering problem; these include the extended Kalman filter (based on small-signal linearization) and several quasi-linear Kalman filters (based on random-input describing function theory). Performance comparisons are obtained by applying the filters to a number of trajectories.

High-performance aircraft are susceptible to degraded flying qualities during maneuvering flight for a number of reasons, including aerodynamic nonlinearities, inertial coupling, and rapidly changing flight condition. Lateral-directional modes of motion coupled with longitudinal motions in asymmetric flight and high angle of attack can lead to instability and adverse control response. The pilot must adapt his control strategies to varying aircraft dynamics, and his work load is high; consequently, improper piloting procedures could occur, leading to inadvertent loss of control.

The Covariance Analysis DEscribing Function Technique (CADET) -- a technique conceived at TASC for the efficient direct statistical analysis of nonlinear systems with random inputs -- is applied to the study of a complicated, highly nonlinear model for a tactical missile homing guidance system. Numerous parameter sensitivity studies are performed, with selected cases verified by the monte carlo method. The validity of the assumptions underlying the CADET theory is investigated and the impact of possible errors in these assumptions on the accuracy of CADET is assessed. In every realistic situation studied, CADET provides accurate missile performance projections with a small fraction of the computer time required for a comparably reliable monte carlo analysis.

This handbook presents detailed instructions for the application of the Covariance Analysis DEscribing Function Technique (CADET TM) to the evaluation of tactical missile guidance systems (both analog and digital). Its contents include: CADET theory, simple illustrative examples (with flowcharts), model development for the missile-target intercept problem, statistical linearization theory, discussions of the capabilities, limitations, and application philosophy of CADET, and an extensive catalog of pertinent random input describing functions. A detailed discussion of monte carlo analysis is appended, both to permit a comparison with CADET and to provide a background for the monte carlo procedures used to verify CADET., See also AD-783 098.