comment to: santos137@yahoo.com
Generalized AutoKite
SPECIFICATION NOTES 0.3 (old, obselete)
Physical
Lightest possible platform aloft
components ever lighter over time, new functions within weight savings.
Simple launch/recovery, & in rough conditions.
hint- upon Outleader retrieval run sled part-way up top sheets to hold doused kite clear of water. scale technique up.
Multiple levels of kite/tether antifouling
underhull mounted pattern of hooks or hook-knife that hooks or cuts overrun kite/tether preventing propfoul.
bow-form guard, prop-cage, or ducted prop.
stop & fold prop as line danger occurs.
kite down drills
autodepower at kite redline power (blow-outs, wind "fuse")
Control
control input fields- commands, sensor data, weather/nav info
output fields- robust kite power (kite control- all actuation), system display
forcast future flying conditions, estimate power delivery, flight time etc.
Commands- System Level- Retrieve, Launch, Cutaway
Subcommands- Brake, Sweep/Scan (left, right, straight), GoTo (window position)
Command control module at ship end, a default microcontroller resides on the kite which is, after all, itself generally form-stable.
System watches new kite/boat/wind performance & learns the case-envelope.
Adaptive learning- the system watches expert human fliers & mimics them. Can be very effective where no adequate formal theory exists, but also opaque & quirky.
models maintainable & expansible to include complexities such as wind shear, operational constraints, etc.
Human Interface
Boat
Standards based- ruggedized PC/display, stock marine/avionic components.
Manual to FBW controls, instruments, (joystick/switches/circuit breakers
Realtime LEO (Low Earth Orbiter) network link enabling telepiloting or troubleshooting kite.
Helm's Display of KiteSessionStatus- Colored symbols overlaid on video with status text.
Command Interface transitional states from any possible state (kite universe) to any desired state (command). Primitive commands like Brake, Accelerate, Left/Port-Right/Starboard Turn, etc.. The primitives then combine into "Scripts", such as Zig-Zag, Retrieve, Jibe, etc. A final level of abstraction might be a Case-Based Reasoning (CPR) module, an evolving Case-Base of emergencies, odd hazards, etc., as the kiteship field matures.
Custom helm/bridge interface integrated into existing shipping. Distributed interface (ie. capt. views from quarters)
Draft System Control Panel ("Glass Cockpit" Control Interface)
Logging Function- enables carbon credit verification, an incentive to fly the sail consistently.
Kite/Distributed
wireless remote access
net portal
handhelds for personnel.
Kite Sensors/Sensing
The Kestrel autopilot has most of the basic flight functions, but a second differential baro would be nice for the kite app..http://www.procerusuav.com/productsKestrelAutopilot.php Kestrel Autopilot
Microavionics on the kite might prove crucial (artificial horizon, radio altimeter, etc.) to make the control system fail-safe- Light cheap attitude gyro desired.
Low-tech light kite mounted phased piezo screamer array & phased boat mic array would sonolocate the kite in dependent of visual noise..
Machine Vision
machine vision an eventual primary sensor for monitoring autokite, with multi-sensing (GPS, Laser Ranging, etc.) providing a back-up "picture".
structure kite environment with beacons, stobes, reflectors, markings,
The real world has mottled light, fog, & dark; colors fade; imagine a mega-mildewed mega-kite, twenty year veteran of the tropics & roaring-forties, of no certain color anymore.
Most visible countershading, paravane & kite, black below, white above. structured graphics of marks & strobe reflectors
Simple laser-ranging (scanner) is independant of target color, needing only a bit of reflectivity (with reflector material it should cut thru fog). A ship mounted Lidar could be designed provide kite surfaces/position information along with wind imaging.
Compact Vision Systems - National Instruments
soaring's golden age nears, Lidar reveals the ghostly lift, but is still too heavy aloft (>70 lbs). Spaced based Lidar may soon (5-10 yrs) provide realtime services to aircraft.
Night vision tech may help operations.
a boat mounted phased microwave antenna array with microwave beacons on kite, would locate kite reliably in all conditions. Some commercial radars are suitable. Kite should be highly radar reflective, anyway.
gyro stabilized surface-based tracking cam v. use ship as reference from kite's view. The kite really only "sees" the tether, likewise the boat (motion) only sees the tether.
3 differential GPS sensors on each kite and boat would give the system a clean picture of immediate past velocity to interpolate from
Differential gps locates wingtips within centimeters absolute-- specify high speed differential gps at ~4 samples per sec. because there are other latencies in the control loop eating time. Wingtips go out of whack, giving a false sense of overall attitude, while blimp/harness attitude is more dominant. Machine Vision offers definitve picture of wing state, eventually.
Acoustic/baro force sensors. monitoring aeroelasticity (the resonant "flutter" of airframes in flight), in a kite the hum of a line/membrane varies with wind/tensioning, structural failure, rain, etc.., white-noise that excites the specific harmonics under observation, which drift with variable tension..
kite/ship "position sensing" module to find kite position, attitude and velocity in the sky relative to the ship ("attitude" relates to the kite's heading, thus its primary direction of potential movement).
To be unaffected by ship's roll, pitch or heave, On ship gyro mount "steady-cam" in lexan dome to buffer out ship motion would be too fast (anti-jitter speed- ship pitch & roll too close to pan/tilt speeds) If all else failed, an oil dampened micro vid-cam in compass globe, mounted on the rose with an external magnet to tug it forward. Use solar cells in the globe to transfer power to cam transmitter. Nah. Just gimbal vidcam/laser ranger/etc. with magnetic or spring dampening, then canceling out residual motion by instrument/servo loops or instrumented pixel translation.
Kite Line/Tether Sensors/Sensing
radio/mag/"barcode" tags along lines for position feedback, line play-out metering embedded sensor targets (like implant ID chips or bar-codes)
tensiometry of line force is useful; simple acoustic pickups might provide a nice force-picture of the kite. Squid Labs embedded line load-cell
tensiometrics key to automating "muscle memory" kiteflying, acoustic tensiometry proposed (line tension divided by length), see acoustic monitoring of kite
Line angle/azimuth uncertainty a function of unknown_windshear x line_length. Real-time sensor feed & past sensor states to extrapolate current kite position, attitude and velocity, Emabedded line angle inclinometers & ship based azimuth astrolabe. Artificial horizon required for rolling boat. Line-angle/azimuth-at-ship unreliable as lines extend into turbulent conditions, useless in some hypercritical scenarios, but useful otherwise (clouds fog, night, vision failure).
Kite Actuators
Hydratech Composite Air cylinders
Modern pneumatic actuators of composite materials provide high power-to-weight, fast response & are salt-proof, compared to more traditional heavy, slow, & vulnerable gearmotors & screwjacks. The actuators come standard with position encoding sensors.
A "soft-goods" revolution- modulating ram-air flow (pulse-hammer pressurization?), chamber pressures, A a flap valved muffin-fan sown in between two chambers could exert powerful trim forces. The drag & weight of flight control lines might be eliminated.
Kite might be launchable/operable as a huge ground effect vehicle, a hovercraft almost, mighty little fans pressurizing key sections off the water.
a fabric aeroactuator, a driven slit, opened by pulling or pushing edges open orthogonal to fabric-plane., a language of flap valves, curtain-fans, bladders, etc. low power actuators to warp the kite- a variable slit, closed or open, openable in two modes, an orthogonal push rod holding the slit.
Helm is an actuation input, ideally integrated with kitesail operation, except in emergency (like collision avoidance, fire, grounding, etc.), when system must fend for itself (depower/winchplay/tacking/retrieving)
KiteSailSpace- the envelope of suitable BoatHeading, BoatSpeed, WindHeading, & WindSpeed, absent of other faults. The entire sky becomes a NoFlyZone when conditions are wrong.
All kite elements should be able to fly as controlled gliders in the event of LineSlack to avoid LineTangle.
variable bridles, bridal logic as first reactive control; ground bridling, as in arches, spread anchors.
Status or State- entire system is always in some known state, with optimal path to any other (positive, available) state.
Low power for light-air & trim-control. Realtime control in a turbulent gale requires fast strong input power, but gets more back out of the system
easier yaw and power control.
Kite Power Supply
Ultra-low power kite requirement, ship to kite power undesirable.
A giant kitesail is a flying power plant; auxilary electric generation/storage is natural. Thin film solar & a trailing spinner generator or, better, an internal duct turbine, in tandem, can cover operations of the onboard control instrumantation/actuation, plus things like strobe/running-lights, even blimp propulsion in calm..
Lithium batteries are the established high power-to-weight chemistry. Notebook computer batt. suggested as a prototype big-kite pack. Much can be done, even with tiny button cells, for small prototypes.
12V proposed as primary prototyping voltage, with 5V USB, 3V for distributed low power..higher v later
Tough outdoor rated lminated Thin-film Solar is about 30 grams per watt, practical for lightweight low-power systems. While less efficient by area than crystaline silicon in direct sun, these amorphus films actually outperform crystals in low light, like shade, poor aiming, cloudy weather, twilight, or winter & are far lighter & cheaper per watt.. Choose the most consistently level top kite surface for best average exposure.
Small plastic ducted turbines driven by ram-air, could also generate useful charge.
Kite Line
tether force comparable to pendulum force in traditional aircraft theory. A displaced kite CG is a second pendulum, both interact to form lis. patterns
A ship-kite wants to be single line, as, in the open ocean, seeking the best winds, it will be freely reeled out too far for effective multi-line control.. at moderate scales multi-line will work out to about a couple hundred yards as mushyness & drag build.
long kite tethers require strobe warning lights every 50 ft (FAA standard for towers). Boat based strobe/spot to delinieate reflective line for human/machine vision.
air, electricity (incl. lightning arrester), light, tensile structure, markers, foil section,
Dyneema tether
Winch
High Speed Capstaned Reels with Dipping Booms, pretty much a giant fishing reel. High speed allows keeping the kite in the air by reeling alone as needed. The kite can is played in lulls & puffs. Capstan stage allows unloaded for reel change.
Conversion Boat
Inflatable Topsides & hull sock over hulks for ocean barges.
lightning arrester
KiteBoat
lightning arresters- short past boat to sea, a sea "ground" required perhaps a paravane takes the zap below. t
The case for purpose-built kite-boats, granted that the retrofitting off non-kite boats is the current focus-
carry large quivers of kites, paravanes, & other specialized perfomance gear.
higher consistency of a dedicated boat system v. misc. boats.
intrinsic electric hydrogen auxillary power with shrouded retractable or towed water turbines with dual generator/propulsion modes,
kitewings on an "albacore" form blimp envelope, resolving the lack of lifting-gas volume in a proper wing, optimizing gas-lift/aero-lift to drag, a kite that need not be retracted in doldrum conditions, a kite that won't get water-bound, less likely to foul, etc.
In pondering the "crazy" pressure oscillations of a porpoising helium envelope, a sweet idea occurred, that a plunging LTA kite approaching the surface can correct itself by directing the already expanding lift gas to the nose area, by using elastic gores in that area. Enough such ideas will lead to a stable sweep patterns with eased control requirements.
Operational Notes-
kite handler gear- hook knife, flotation, ELB, dyepack or streamer marker, piezo-screamer (buried under kite), strobe, etc.. Diver on-call, rescue, prop unfouling, spare kites, lines, c..
extreme danger to handlers by giant kites, body-tether risks (hangman's lethality)
kite capable of untethered controlled flight & might cutaway (untether) recover or even shuttle themselves.
Draw KiteSailors from (rock & alpinist)climbing, skdiving, hang gliding, paragliding, trapese artists, riggers (fishing, mine-sweeping,) exteme kite sports. SkySailor fun- toplounging, flying service rappels, tarzan-swinging in batsuits
High winds, small kites, & hot kites eat realtime control.
Cutaway notes- auto depower/cripple wings, deploy sea anchor as unliftable waterbag, BreakAway similar to Cutaway. A "cutaway" in skydiving. a hook knife suffices for a yacht, katchet/machete/ax variations, explosive guioines, snap shackles. Cutaway might be a standard on-command option eventually, routine, recoverable, repeatable, a standard drill. Cutaways tracked & retieved ELB (Emergency Locater Beacon) on kite & RDF on boat. New cutaway gear in skydiving, hang/paragliding, ultralights, etc.
Kites can create lightning hazard- paravane could ground kite, bypassing ship. Ship could have conventional lightning arresters installed at kitewinch connected to shipground conductor.
Kite-towing by kite-tugs, electric aircraft that hot swap elements in a kite-array.
Towing thru calms & reeling in lulls & puffs.
Multilines- kite/paravane oriented to "control bar".
Line untwist/nontwist required, swivels, ultralight giant swivels?
Neural Nets? The kitebot might be tamed by using a human expert flyer as a neural net trainer. Neural nets have only a few flaky niches; kites smell like a match. Best case, the elusive "muscle memory" of a master flyer magicly appears in kitebot behavior. Not so good, the trainer may have vital sensory cues unavailable to the neural net, degrading performance/stability.. Neural nets are also opaque to things like normal validation, maintenance & troubleshooting,
a rotating turret that integrates launch/retrieve chute
LTA Kite Operations
>Do we get such pressure oscillations even with the small altitude changes
we envision? We're looking at the difference between 300 and 1000 ft
altitude.//yes, you could burst a seam or crumple like a prune with ~modest altitude change (few hundred feet) if inflation pressure not precisely balanced. A superpressurized balloon passively holds shape, but its a ~bomb. So do Rigids with floppy lift cells within, but at a weight cost. Maybe KiteShip's should have an inflatable skeleton, for light rigidity.
Active balloonet system desirablion compensate for relentless helium loss. Also daily temp variation, even solation flux, varies pressure signifigantly, less lift at night.
Kite Fishing Balloons lift kite in light wind or fly alone in no wind. Capt. Bob Lewis, Paul('s fish kites) refined these techniques..
Misc. Kite Notes
Active Sweep Control- The figure-eight sweep pattern feels good. It is the simplest harmonic Lissajous Curve, nature's original doodle. The curve stretches into a sine wave distorted by dives v. climbs, when dragged along at the Kite Window's luff edge of a windward-bound kiteboat. I spotted these patterns projected on a wall by sunlight glancing off the breese ripples in a full rain-bucket, strong impression of a future where ribbon sails ripple wildly in towering sweep patterns.
The figure-eight dynamic could be harmonized with helicity.
demonstration of stable self sweep geometries for low-energy control inputs. Sept. 6,'07, Long Beach, WA, by spreading out control handles of a sport-kite, it took up a stable back & forth sweep, period controllable by varying the spread.
The kite crosses the power zone on a tilt & slows toward the window edge, tail swings like a pendulum, pulling kite to face back across window. Kite accelerates across power zone again & repeats cycle on other side of the window.
getting kite to power its own actuation, a pilot surface cascades the response of a large surface.
kite flight is the interaction of wind & acceleration forces. Tether force is acceleration, like gravity (a highly warped second gravity). Tether force & gravity are orthogonal at horizon & near parallel overhead, tethered space is highly curved inside of flat space of wind & suface. Whoa, no wonder kites crash.
problem- LTA won't prevent death dive at low positive bouyancy as surging kite overpowers modest lift.
proof that the major-state-machine correctly implements the top-spec..
As a rule, attitude control must dominate any random dynamic buffeting expected to occur. Bigger control surfaces for light conditions, faster stronger controls for heavy air.
a simple tiltmeter could provide the input to control kite-yaw in the danger zone.
The full kite train spans three fuzzy zones of operation, aloft in proximity to the boat, moderately aloft, & far aloft. Maximum pull is attained by the full train.
comment to: santos137@yahoo.com