Safe2Ditch Technology

robotics automation and control
Safe2Ditch Technology (LAR-TOPS-243)
Autonomous crash management to a safe and clear ditch site for small UAVs
Highly capable small UAVs provide substantial business opportunity, especially if allowed to operate in the suburban market. Reliability issues force the use of a safety pilot for each vehicle in operation, which is cost-prohibitive for large scale commercial applications and limits the use of these vehicles to line-of-site (LOS) operation. Extending the use of small UAVs to beyond visual-line-of-sight (BVLOS) and to fleet operations requires a vehicle system to autonomously perform emergency management activities as a replacement to the human pilot to maintain safety to people and property in populated areas.

The Technology
Safe2Ditch is a crash management system that resides on a small processor onboard a small Unmanned Aerial Vehicle (UAV). The system's exclusive mission is emergency management to get the vehicle safely to the ground in the event of an unexpected critical flight issue. It uses the remaining control authority and battery life of the crippled vehicle in an optimal way to reach the safest ditch location possible. It performs this mission autonomously, without any assistance from a safety pilot or ground station. In the event of an imminent crash, Safe2Ditch uses its intelligent algorithms, knowledge of the local area, and knowledge of the disabled vehicle's remaining control authority to select and steer to a crash location that minimizes risk to people and property. As it approaches the site, it uses machine vision to inspect the selected site to ensure that it is clear as expected.
Sample Safe2Ditch Operational Scenario. Image credit: NASA
  • Compact, lightweight and low cost
  • Onboard adaptive controls allow a disabled UAV to reach a selected emergency landing zone
  • Designed to operate with autopilot systems favored by the very small UAV market

  • The Safe2Ditch system will reside on small UAVs as one of several onboard systems
  • A large commercial UAV market is emerging to serve the urban/suburban environment -Home/business deliveries -Live remote transmission -Many others (roof inspection, real estate, etc.)
Technology Details

robotics automation and control
Similar Results
Reliable Geo-Limitation Algorithm for Unmanned Aircraft
Safeguard is an independent avionics equipment that can be easily ported to virtually any UA. The current prototype weighs approximately 1 lb (without hardware optimization). The invention innovations include formally verified algorithms to monitor and predict impending boundary violations through flight termination trajectory estimation. A system could be configured without sole reliance on the GPS to avoid known problems with GPS inaccuracies and unavailability. It can operate independent of the UA and any on-board components, such as the autopilot, for physical and logical separation from non-aviation-grade systems. The perimeter boundaries are described using polygons, which can approximate almost any shape, and there are practically no limits to the number of shapes and boundaries. The algorithms for establishing the validity of a boundary and for detecting proximity to all defined boundaries are based on rigorous mathematical models that have been formally verified. Software required to operate cannot be licensed from NASA, the licensee must create and/or procure separately.
Low Weight Flight Controller Design
Increasing demand for smaller UAVs (e.g., sometimes with wingspans on the order of six inches and weighing less than one pound) generated a need for much smaller flight and sensing equipment. NASA Langley's new sensing and flight control system for small UAVs includes both an active flight control board and an avionics sensor board. Together, these compare the status of the UAVs position, heading, and orientation with the pre-programmed data to determine and apply the flight control inputs needed to maintain the desired course. To satisfy the small form-factor system requirements, micro-electro-mechanical systems (MEMS) are used to realize the various flight control sensing devices. MEMS-based devices are commercially available single-chip devices that lend themselves to easy integration onto a circuit board. The system uses less energy than current systems, allowing solar panels planted on the vehicle to generate the systems power. While the lightweight technology was designed for smaller UAVs, the sensors could be distributed throughout larger UAVs, depending on the application.
VTOL compound wings include integral lift engines, articulating outboard wing sections, and a rotatable aft propulsor.
Small Compound-Wing VTOL UAS
This UAS technology defines a part-time VTOL system that transitions to efficient fixed-wing operation to obtain desired endurance and range. A novel three-segment wing design includes: a fixed Inner segment mounted to the fuselage, a controlled, articulating intermediate segment to which lift engines are attached, and a free-to-rotate outer segment to alleviate gust impacts on the airframe in both modes. The aft propulsor is articulated and configured such that the thrust being generated is always in a proverse direction. Also, the controlled-articulation wing segments are operated in both tandem and differential modes to allow for direct control while in the various modes of operation. Also incorporated is a novel control architecture that encompasses both the different system operating modes as well as the considerable number of individual control options and combinations.
AVA Controller
Affordable Vehicle Avionics (AVA)
Significant contributors to the cost of launching nano- and micro-satellites to orbit are the costs of software, and Guidance, Navigation and Control (GNC) avionics systems that steer, navigate and control the launch vehicles, sequence stage separation, deploy payloads, and pass data to Telemetry. The high costs of these GNC avionics systems are due in part to the current practice of developing unique, custom, single-use hardware and software for each launch, and requiring high-precision measurements of position and attitude states. NASA Ames Research Center has developed and tested a low-cost avionics system prototype called Affordable Vehicle Avionics (AVA). AVA integrates a low-cost moderately-precise sensor suite with an advanced error-correcting software package to provide GNC for space launch vehicles in a package smaller than a multilayer sandwich (100 mm x 120 mm x 69 mm; 4in x 4.7in x 2.7in), and with a mass of less than 0.84kg (2lbs). The invention provides a common suite of avionics components and demonstration software that deliver affordable, capable GNC with flexible I/O which is applicable to a variety of nano/micro-sat launch vehicles at less than 10 percent of the cost to procure current state-of-the-art GNC avionics. Affordable Vehicle Avionics' (AVA's) approach to drastically reduce costs includes: (1) use of low-cost "tactical-grade" Commercial-off-the-Shelf MicroElectroMechanical Systems (MEMS) inertial measurement unit, wherein adequate navigation precision is achieved by fusing outputs from a Global Positioning System receiver, inertial sensors and a magnetic field vector sensor in an extended Kalman filter formulation that corrects inertial sensor biases; (2) a streamlined "cookbook" approach to define an effective process for launch vehicle developers to design, simulate, verify and support assembly, integration and testing of their SLVs, driven by high-fidelity six degrees of freedom SLV simulations and real-time hardware-in-loop tests to validate guidance, navigation and control for early test flights. Development Status: As of spring 2020, AVA has flown twice in its current configuration on a suborbital platform. Its navigation and control functions were successfully demonstrated for roll-rate control within a tight deadband onboard the first flight test, and it successfully issued attitude pointing commands to a failed reaction control subsystem and it issues issued a rocket-motor ignition command on a second flight test. To date, failure of SLV components other than AVA (e.g., electrical power) has precluded demonstration of navigation and control of an orbital or sub-orbital launch system, which remains to be demonstrated. AVA development was accomplished using a single magnetometer-based magnetic field vector sensor to provide attitude observability during free-fall (inter-stage coast periods). Therefore, the current tested AVA configuration is susceptible to magnetic/electric fields produced by other components and payloads onboard the SLV, so care must be exercised to either mount AVA well away from sources of such fields and or to incorporate magnetic/electric field barriers on field emitters if separation from emitters is inadequate. Also, licensees may wish to provide new AVA inputs from a pair of external horizon sensors to provide more accurate attitude navigation during coast phases of the SLV mission.
technology drawing
Aircraft Vertical Takeoff & Landing
This technology is a vertical takeoff and landing (VTOL) aircraft that is a modification of a conventional single-prop aircraft design. The addition of vertically oriented, stowable tail rotors and an articulating forward rotor, capable of pivoting from a horizontal to vertical orientation, enables VTOL capabilities. It combines the speed and fuel efficiency of fixed wing aircraft with the hoverability and flexibility of rotary aircraft. The VTOL is designed for easy stowing in a cargo van making it easy to transport. The design is expected to avoid the compromises in performance that are typically made in development of VTOL aircraft.
Stay up to date, follow NASA's Technology Transfer Program on:
facebook twitter linkedin youtube
Facebook Logo Twitter Logo Linkedin Logo Youtube Logo