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Hatch, H. G., Jr.

Publications and source records attributed to Hatch, H. G., Jr..

An approach to the determination of aircraft handling qualities using pilot transfer functions

It was shown that a correlation exists between pilot-aircraft system closed-loop characteristics, determined by using analytical expressions for pilot response along with the analytical expression for the aircraft response, and pilot ratings obtained in many previous flight and simulation studies. Two different levels of preferred pilot response were used. These levels were: (1) a static gain and a second-order lag function with a lag time constant of 0.2 second; and (2) a static gain, a lead time constant of 1 second, and a 0.2-second lag time constant. If a system response with a pitch-angle time constant of 2.6 seconds and a stable oscillatory mode of motion with a period of 2.5 seconds could be achieved with the first-level pilot model, it was shown that the pilot rating will be satisfactory for that vehicle.

Adams, J. J.↗

The use of minimum order state observers in digital flight-control systems.

This paper deals with the problem of selecting the 'arbitrary' design parameters of digital state observers when they are being used as a part of a digital flight-control system. A cost index is developed which indicates the output noise caused by input quantization due to analog-to-digital conversion. The cost index assumes that the input quantization error is uniformly distributed over the least-significant-bit of the conversion. Formulas relating the cost index to the observer design parameters are presented. The cost index is minimized with respect to the design parameters using a conjugate gradient algorithm. An example of the theory is presented in which a digital observer is designed so that a satisfactory digital flight-control system is obtained starting from an unacceptable one.

Montgomery, R. C.↗