CoolIP index                                                          Most recent edit: Wednesday December 19, 2012

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Novel Machine Vision Solution For Determining Kite State

Minute changes in kiteline angle and line curvature at the surface deterministically reflect the position, orientation, velocity, and pull of a kite aloft. Crude mechanical line-position encoders are common on AWES-developmental platforms, but prone to damage and uncertainty (especially during transient line slackness). Elaborate multisensing at the kite [wing of the kite system] is commonly specified to avoid the uncertainty mechanical encoders suffer from. A separate line-tension sensor is usual. A better line-encoding method is needed to help resolve kite state.

To adequately monitor kite state for control purposes, it may suffice for kiteline geometry at the anchor point to be closely imaged within a dark fabric "boot" by stereo micro video (or en-plein-air by micro laser scanner). The kitelines in the boot would be artificially lit for an easily processed image. A stereo-pair requirement could be met with just one camera and mirror(s) in the view field.

The system could be sensitive to events that mechanical encoders miss. Even twisted-line states can in principle be disambiguated by this sort of close videogrammetry. A look-up table (database) of local line states would output the detected kite state. Markov chains, Bayesian inference, or model predictive control could interpret and act on this state accordingly.

To complete a minimalist sensor suite, an encoded reel can keep track of line length. Acoustic monitoring of line noise could be a semi-redundant data source (topic for a separate post). Avionics on the kite remains an option, working even better without mechanical line-encoder uncertainty to worry about. Meteorological sensors and METAR data would be a given, helping factor out hodographic twist, for example. A simple limit switch/sensor could react to, or confirm, a kite returned to a cradle.

The proposed machine-vision kite state detection method would be immune to many normal failings of outdoor vision systems, such as sun glare, night lighting, fog, and bird droppings or raindrops on a lens. It would eliminate the inherent flaws of mechanical line position encoders. It could be an ultimately cheap solution as well.

Comment and development of this topic will be occurring here.       
All, send notes, links, drawings, and photographs!

  • Terms and aspects:   
    • kite state, kite states  [[Often a writer will mean kite-wing-set state when writing "kite state" in discussions. As a kite is a combine of wing set, tether set, and resistive or reaction set, then kite state would include the state of the wing set, tether set, and anchor or reaction set. Look to context to note if the author is with a focus just on the wing set of a kite (kite system).]]
    • wing-set state
    • tether-set state
    • resistive-set state
    • wiki: Hodograph
    • machine-vision kite state detection method
    • en-plein-air
  • Related links and concepts:
  • Commentary is welcome:

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