Small Business Innovation Research/Small Business Tech Transfer
Virtual Redundancy for Safety Assurance in the Presence of Sensor Failures
Project Description
Both vehicle automation systems and human pilots rely heavily on sensor feedback to safely control aircraft. The loss of reliable information for even a single state feedback signal can initiate a chain of events that leads to an accident. On small aircraft, hardware redundancy is often impractical and the failure of a single physical sensor could be the triggering event that leads to an accident. On commercial transport aircraft sensor hardware redundancy is common, but the potential for common-mode failures means sensor failures are still an important consideration. In many cases, there is adequate information available to accurately estimate the true value of a parameter even if the sensor or sensors that directly measure the parameter have failed. In the best case, a human pilot can exploit the available information to successfully fly the vehicle after a sensor failure, but it is a high workload task. In many cases, lack of situational awareness and poor manual piloting skills create a situation in which the human pilot cannot safely handle the failure. Similarly, many automation systems are unable to safely cope with failures. The proposed research will build on the successful phase one proof-of-concept demonstration to develop a virtual sensor redundancy system that identifies and isolates faulted sensors, and fuses information from healthy sensors and vehicle dynamics models (including arbitrary nonlinear models) to estimate correct outputs for faulted sensors. The research will also develop the Virtual Sensor Toolkit, a software tool that supports the entire lifecycle of virtual sensor development and deployment from requirements development to testing and design updates. Barron Associates has partnered with commercial unmanned air system producers to advance the TRL of the technology through an aggressive Phase II development and testing effort that prepares the team for flight tests immediately following Phase II.
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Anticipated Benefits
The proposed research is closely aligned with the goals of the Airspace Operations and Safety Program (AOSP). The loss of accurate sensor data presents significant hazards to both air vehicles being manually piloted and those using high levels of automation. The virtual sensor redundancy technology effectively mitigates failures of physical sensors, including common-mode failures that may affect multiple redundant physical sensors, and provides a continuous stream of accurate sensor data. The reliable input data provided by the virtual sensor system will enhance the robustness of vehicle automation systems, directly supporting the goals of the Safe Autonomous Systems Operations (SASO) project within AOSP. Onboard system failures including sensor failures are an important class of precursor events to vehicle upsets. By mitigating these failures, virtual sensor systems reduce the likelihood of automation failures and provide accurate information for manual piloting, thereby reducing the likelihood of an upset event. This capability directly supports work in the area of Technologies for Assuring Safe Aircraft Energy and Attitude State (TASEAS) within the Airspace Technology Demonstrations (ATD) project of AOSP.
The proposed technology is applicable to a wide range of air vehicles, both manned and unmanned. Ultimately, Barron Associates seeks to apply the technology to commercial transport aircraft, and the Air France 447 crash, for which a common-mode failure of multiple pitot tubes has been identified as a key initiating event, demonstrates the need for the technology. In the near term, small unmanned air systems represent a large potential market. Size weight and power constraints severely limit hardware redundancy on these platforms, and small low cost sensors are often less reliable than those used on larger more expensive platforms, creating a significant need for the proposed technology. Small general aviation vehicles also typically have very limited hardware redundancy, and with glass cockpit technology becoming increasingly common in even the small vehicles, Barron Associates sees significant market potential here as well. Beyond air vehicles, autonomous ground and marine vehicles represent significant potential markets. Many automobiles already offer limited automation capabilities to enhance safety, and fully autonomous vehicles may become commonplace in the foreseeable future. Automation systems on these vehicles have the same need for reliable input data as those on air vehicles and, especially on roadways, safety will be paramount. The virtual sensor technology is thus expected to have significant market appeal in this sector. More »
The proposed technology is applicable to a wide range of air vehicles, both manned and unmanned. Ultimately, Barron Associates seeks to apply the technology to commercial transport aircraft, and the Air France 447 crash, for which a common-mode failure of multiple pitot tubes has been identified as a key initiating event, demonstrates the need for the technology. In the near term, small unmanned air systems represent a large potential market. Size weight and power constraints severely limit hardware redundancy on these platforms, and small low cost sensors are often less reliable than those used on larger more expensive platforms, creating a significant need for the proposed technology. Small general aviation vehicles also typically have very limited hardware redundancy, and with glass cockpit technology becoming increasingly common in even the small vehicles, Barron Associates sees significant market potential here as well. Beyond air vehicles, autonomous ground and marine vehicles represent significant potential markets. Many automobiles already offer limited automation capabilities to enhance safety, and fully autonomous vehicles may become commonplace in the foreseeable future. Automation systems on these vehicles have the same need for reliable input data as those on air vehicles and, especially on roadways, safety will be paramount. The virtual sensor technology is thus expected to have significant market appeal in this sector. More »
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Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Barron Associates, Inc. | Lead Organization | Industry | Charlottesville, Virginia |
Langley Research Center
(LaRC)
|
Supporting Organization | NASA Center | Hampton, Virginia |
Primary U.S. Work Locations
-
Virginia
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