Digital Flight Control Research Using Microprocessor Technology.
Annual technical rept. no. 1, 1 Feb 78-31 Jan 79,
PRINCETON UNIV NJ DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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A digital flight control system based on microprocessor technology was designed, developed, and flight tested in Princetons Variable-Response Research Aircraft VRA. The microprocessor-based digital flight control system works in conjunction with the VRAs existing fly-by-wire control system, and is programmed to provide command and stability augmentation control laws formulated through modern control theory. The initial flight control computer program, CAS-1, provides direct, pitch rate, and normal acceleration command modes. The latter two closed-loop control laws are designed using sampled-data linear-quadratic regulator theory. The computer hardware and software are described and initial flight test results are presented. Flight test results are based on two longitudinal manual control tasks tracking at altitude and approach and landing. They demonstrate the effects of varying sampling rate, computation delay, and control resolution on calibrated step response and on pilot opinion ratings. It is concluded that the pilot can provide effective control with lower sampling rates and control resolution than might have been anticipated. The limiting values are task dependent, generally lying in the range of 5 to 10 samples per sec and 4- to 8-bit resolution. Flight test results with pure time delay tend to confirm that there is rapid degradation of pilot opinion as the delay increases beyond 0.2 sec.
- Flight Control and Instrumentation
- Computer Programming and Software
- Computer Hardware