Advanced flight control system study

A fly by wire flight control system architecture designed for high reliability includes spare sensor and computer elements to permit safe dispatch with failed elements, thereby reducing unscheduled maintenance. A methodology capable of demonstrating that the architecture does achieve the predicted performance characteristics consists of a hierarchy of activities ranging from analytical calculations of system reliability and formal methods of software verification to iron bird testing followed by flight evaluation. Interfacing this architecture to the Lockheed S-3A aircraft for flight test is discussed. This testbed vehicle can be expanded to support flight experiments in advanced aerodynamics, electromechanical actuators, secondary power systems, flight management, new displays, and air traffic control concepts

Avionics architecture studies for the entry research vehicle

This report is the culmination of a year-long investigation of the avionics architecture for NASA's Entry Research Vehicle (ERV). The Entry Research Vehicle is conceived to be an unmanned, autonomous spacecraft to be deployed from the Shuttle. It will perform various aerodynamic and propulsive maneuvers in orbit and land at Edwards AFB after a 5 to 10 hour mission. The design and analysis of the vehicle's avionics architecture are detailed here. The architecture consists of a central triply redundant ultra-reliable fault tolerant processor attached to three replicated and distributed MIL-STD-1553 buses for input and output. The reliability analysis is detailed here. The architecture was found to be sufficiently reliable for the ERV mission plan

Advanced flight control system study

The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

Preliminary candidate advanced avionics system for general aviation

An integrated avionics system design was carried out to the level which indicates subsystem function, and the methods of overall system integration. Sufficient detail was included to allow identification of possible system component technologies, and to perform reliability, modularity, maintainability, cost, and risk analysis upon the system design. Retrofit to older aircraft, availability of this system to the single engine two place aircraft, was considered

Study report recommendations for the next generation Range Safety System (RSS) Integrated Receiver/Decoder (IRD)

The Integrated Receiver/Decoder (IRD) currently used on the Space Shuttle was designed in the 1980 and prior time frame. Over the past 12 years, several parts have become obsolete or difficult to obtain. As directed by the Marshall Space Flight Center, a primary objective is to investigate updating the IRD design using the latest technology subsystems. To take advantage of experience with the current designs, an analysis of failures and a review of discrepancy reports, material review board actions, scrap, etc. are given. A recommended new design designated as the Advanced Receiver/Decoder (ARD) is presented. This design uses the latest technology components to simplify circuits, improve performance, reduce size and cost, and improve reliability. A self-test command is recommended that can improve and simplify operational procedures. Here, the new design is contrasted with the old. Possible simplification of the total Range Safety System is discussed, as is a single-step crypto technique that can improve and simplify operational procedures

Simulation and control engineering studies of NASA-Ames 40 foot by 80 foot/80 foot by 120 foot wind tunnels

The development and use of a digital computer simulation of the proposed wind tunnel facility is described. The feasibility of automatic control of wind tunnel airspeed and other parameters was examined. Specifications and implementation recommendations for a computer based automatic control and monitoring system are presented

Fault Injection for Embedded Microprocessor-based Systems

Microprocessor-based embedded systems are increasingly used to control safety-critical systems (e.g., air and railway traffic control, nuclear plant control, aircraft and car control). In this case, fault tolerance mechanisms are introduced at the hardware and software level. Debugging and verifying the correct design and implementation of these mechanisms ask for effective environments, and Fault Injection represents a viable solution for their implementation. In this paper we present a Fault Injection environment, named FlexFI, suitable to assess the correctness of the design and implementation of the hardware and software mechanisms existing in embedded microprocessor-based systems, and to compute the fault coverage they provide. The paper describes and analyzes different solutions for implementing the most critical modules, which differ in terms of cost, speed, and intrusiveness in the original system behavio

"Development of wireless fire products”

The project was to develop a radio controlled door holder system as the first in a range of radio based products for Stephenson Gobin Eng Co. Ltd. Stephenson Gobin manufacture and market a wide range of electromechanical products, including retaining devices for fire doors and smoke vents. Typical installations are in hospitals, nursing homes, shopping centers, hotels or any building open to the public. The author discusses why a radio controlled door holder system is commercially and technically viable. Various wired and Wirefree door holder systems are evaluated on merits of safety and ease of installation. Stephenson Gobin developed a bi-stable latching door holding device which consumed no current in a state that was capable of holding a fire door open. This was due to a rotating magnetic slug assembly which only drew current to latch from one state to other. The device needed to be controlled wirelessly and possible methods of communication were assessed. Communicating using the license free radio frequency spectrum was selected due to the falling costs of radio components and the huge growth in the radio communication sector. The author developed and tested the hardware and software necessary to communicate with and actuate such a device

Intelligent redundant actuation system requirements and preliminary system design

Several redundant actuation system configurations were designed and demonstrated to satisfy the stringent operational requirements of advanced flight control systems. However, this has been accomplished largely through brute force hardware redundancy, resulting in significantly increased computational requirements on the flight control computers which perform the failure analysis and reconfiguration management. Modern technology now provides powerful, low-cost microprocessors which are effective in performing failure isolation and configuration management at the local actuator level. One such concept, called an Intelligent Redundant Actuation System (IRAS), significantly reduces the flight control computer requirements and performs the local tasks more comprehensively than previously feasible. The requirements and preliminary design of an experimental laboratory system capable of demonstrating the concept and sufficiently flexible to explore a variety of configurations are discussed