Aerobots as a Ubiquitous Part of Society Larry A. Young* Flight Vehicle Research and Technology Division NASA Ames Research Center, Moffett Field, CA, 94035-1000 Small autonomous aerial robots (aerobots) have the potential to make significant positive contributions to modern society. Aerobots of various vehicle-types – CTOL, STOL, VTOL, and even possibly LTA – will be a part of a new paradigm for the distribution of goods and services. Aerobots as a class of vehicles may test the boundaries of aircraft design. New system analysis and design tools will be required in order to account for the new technologies and design parameters/constraints for such vehicles. The analysis tools also provide new approaches to defining/assessing technology goals and objectives and the technology portfolio necessary to accomplish those goals and objectives. Using the aerobot concept as an illustrative test case, key attributes of these analysis tools are discussed. Notation j’th technology, to i’th goal L/D Vehicle lift-to-drag ratio Alt Altitude (above ground level), m PE Potential energy of vehicle, Joules d Total distance traveled on a delivery route (dT for Pev Probability of successful evasive maneuvers to a truck/automobile and dA for an aerobot), km avoid D Vector/array representing the consistency of the PF Probability of vehicle system failure that leads to particular individual technology with strategic significant degradation of control technical direction guidance Pimp Probability of vehicle/object flight-path conflict, eA/eT Ratio of aerobot energy expenditure (per subject to no evasive actions or other mitigation kilometer traveled) over energy expended per Pmit Probability of successful impact mitigation kilometer by a truck/automobile RP CTOL or STOL propeller radius E Vehicle impact energy, Joules RR VTOL “lifting” rotor radius, m 2 EALim Distributed impact energy limit, J/m q QFD-inspired technology-to-goals matrix f Vehicle frontal area, m2 R Aerobot nominal range, m g Gravitational constant, m/s2 S Wing planform area, m2 G1 Candidate goals matrix T Vector/array captures institutional core G2 Candidate objectives matrix competency expertise or growth interest in a IEP Rotational inertia of “exposed” propulsor particular individual technology, ranging from 0 K Vector/array representing the cost associated to 10 (no to high expertise/interest) with the development/implementation of a T/W Vehicle thrust-to-weight ratio particular individual technology (1 low to 10 U Vector/array representing the risk of high) development/implementation of a particular KEAF Kinetic energy of airframe, Joules individual technology (1 low to 10 high) KEEP Rotational kinetic energy of “exposed” V Vehicle horizontal velocity, m/s propulsor, Joules VC Cruise velocity, m/s m Aerobot “total gross weight” mass, kg VROC Vertical rate of climb, m/s n Vehicle load factor VStall Stall velocity, m/s NCTjTiG Number of contributing technologies, including VTip Propulsor “tip” velocity, m/s *Presented at the AHS Vertical Lift Aircraft Design Conference, San Francisco, California, January 18-20, 2006. Copyright © 2006 by the American Helicopter Society International, Inc. All rights reserved. 1 AHS International x Mean distance traveled (via either truck, landing (CTOL, STOL, and VTOL) platforms1. How automobile or aerobot) per package/stop, km are aerobots different from uninhabited aerial vehicles (UAVs)? UAVs are clearly a subset of the proposed ε* Normalized “elegance” metric (computational (more general) class aerobots. However, it is intended efficiency for autonomous system that aerobots embody a degree of intelligence and implementation), ranges numerically from 0-10 functionality to enable more than merely autonomous φSA Level of aerobot situational awareness impact flight between two given take-off and landing mitigation parameter, numeric value ranges from waypoints. 0-10 (low to high situational awareness) φSW Level of impact mitigation stemming through This vision of aerobots becoming an integrated part human-to-machine and machine-to-machine of society promises great benefits and significant communication and coordination (signals and challenges. This paper discusses both of these aspects warnings), 0-10 (low to high level) of the notional aerobot paradigm. A number of notional mission requirements/profiles are outlined φFT Level of flight termination impact mitigation parameter, ranges numerically from 0-10 (low to consistent with the overall anticipated aerobot high level of protection stemming from application domain; a suite of specific aerobot concepts aggregate influence of implemented fail-safe is provided as a result of the conceptualization process. measures – i.e. parachutes, inflatable bags, A modest amount of precursor developmental work treated airframe surfaces, engine cut-outs with 2-3 propeller/rotor brakes, etc) has been focused on aerobots . However, platform " “Total system” predictive capability “level of development alone is not sufficient. The successful fidelity,” ranges from 0 to 10 (low to high) widespread introduction of aerobots will dictate the * definition, development, and management (distributed, ι Normalized intelligence metric, for a given level not centralized) of a new type of air space, or rather of autonomy, ranges numerically from 0-10 “inter-space” – i.e. inter(personal) inter(action) -space. ! κ Multiplier factor accounting for probabilistic “Inter-space” for purposes of this paper is defined as influence of evasive maneuvers and other impact being below 120 m AGL (above ground level). “Inter- mitigation measures space” is the air space most likely to be populated by Localized population density of aerobots, ρA small personal-service aerobots. The term “inter- number of aerobots per square meter of over- space” is introduced to reflect the envisioned use of flight terrain these small aerobots as providers of distributed personal ρAC Localized population density of aircraft flying services – which thus must interact closely with human over “aerobot inter-space” in the national beings just immediately above and within the environs airspace system (NAS), aircraft per square meter of humans. Figure 1 graphically illustrates this vision ρP Localized human population density, number of of aerobots becoming an essential component of our people per square meter society – i.e. such vehicles becoming key components ρT Property frontage “terrain clutter”, number of of our future urban/suburban landscapes. objects (of a prescribed size), on or near the ground, per square meter Ω Rotational speed of “exposed” propulsor, radian/s ζ Distributed energy imparted during probable impacts, subject to probable evasive action and other mitigation, J/m2 " Level of autonomy (LOA), ranges from 0-5 ! Introduction Fig. 1. Aerobots: small aerial vehicles providing THE application of robotics and autonomous goods (e.g. delivering a small package) and services system technologies to small-scale aerial vehicles is resulting in the creation of a class of devices that could Central to the inter-space concept is that large be called “aerobots” (aerial robots). These aerial robots numbers of aerobots will be flying over urban areas, so will be of many different vehicle configurations – as to maximize their utility for the distribution of goods including conventional, short, and vertical takeoff and and services. A representative sample of the types of 2 AHS International services and utility functions that could be potentially provided by aerobots is summarized in Table 1. Table 1. General personal services that could be provided by Aerobots Service Competing Advantages Relative to Other Providers Disadvantages Relative to Other Providers Provided Service Providers Utility -- small Bike messenger, - Potential fuel/energy economies, as well - Public safety issues that will have to be addressed package postal carrier, or commensurate reductions in emissions - Achieving high reliability for small aerobots delivery automotive (car, - Substantial improvements in customer service - (End-to-end) system automation challenges truck, motorcycle) in terms of service convenience, timeliness, - Public acceptance of a radically new approach to delivery security, and privacy - Modest but necessary infrastructure changes - Unprecedented provision of on-demand/just-in- time goods and services Utility -- Company - Small distributors/providers of specialty goods - Have to insure that product integrity is preserved consumable automotive could establish a greater market base using throughout the supplier-to-consumer network, both delivery (i.e. delivery or self- aerobots for on-demand delivery during nominal and potentially disrupted deliveries food, water, service personal - Greater goods/services access for shut-ins, or - Insure adequate mitigation steps are taken to medical automobile elderly, ill and/or disabled individuals, minimize potential for theft/misappropriation of supplies) particularly for perishable and time-sensitive good and services (sensitive issue when removing items the immediate human presence during deliveries) - Automated end-to-end transfer/transport of perishables/consumables may be difficult to achieve Personal or On-foot neighbor - Mobility of platforms provides for enhanced - Insuring privacy rights of both neighborhood watch, stationary persistent and/or rapid response security neighborhood/property residents/occupants -- and, security and/or pan and tilt (tele)presence legally entitled, nonresident passersby – while cameras, or