Someone was asking on ARocket about where to start with building a differentially throttled hovering vehicle. Lots of advice were given by various people. I’ll show some stuff I quickly sketched back in 2007 with Simulink. It’s such an easy to use and awesome software (especially compared to a recent short battling with LabView), that whipping up any control system or any process or system models are really quick jobs.

This is just some really trivial basics, it doesn’t take into account nearly enough things to produce a real hovering vehicle. I guess it’s just a way to show how things could be started.

So, here’s a pic of a simple one-dimensional rotational feedback system. Just tested some feedback coefficient values for the PD controller.

1) You can see the placeholder “guidance algorithm” output at the top left “scope” graph. This is the reference or target value of the angle where we want the vehicle to be. At the start it’s giving a desired angle of zero radians, then from 4 seconds onwards it suddenly wants 0.5 radians, then again zero after 6 seconds. This could be holding a tilt for a while for getting up some lateral velocity for a transverse move.

2)  Below that, you see Theta, the angle that the vehicle actually had during the simulation. It follows the desired angle quite nicely. Below Theta, there’s omega, the angular velocity.

3) The tilting is done by throttling the two thrusters. At top center and top right you can see the values of the throttles. Since this thing only concerns tilt and not stationary hovering, the throttles are at zero when the vehicle is at the right attitude (reference=Theta) and there’s no angular velocity. When the refence is moved, at 4 seconds, throttle 1 shoots up for a while and the vehicle starts tilting. At around 4.8 seconds the other thruster, throttle 2 shoots up to stop the rotation, since the vehicle is nearing the desired angle.

You can see from the block diagram how the error value, E = theta – reference is calculated. And also omega is used. From these the throttle values are calculated, simply by Throttle1 = E*Kp1 + omega*Kd1 and so on. By fiddling with the Kp and Kd values, called gains, one can tune the system. The values currently are just some I quickly tried back then.  This Simulink model actually has a bug, a sign error. The error signal’s difference calculation is backwards, hence Kp1 and Kd1 are negative. It should be the other way around.

You can tune the model. Basically, raising the proportional values makes the system faster (reach desired values quicker) but gives overshooting and can make the system oscillate unstably. Higher derivative gains remove the tendency to oscillate, but the system becomes more sensitive to noise (noise can after all have large derivatives). If the vehicle had problems of always staying some amount off from the final required attitude value, an error integrator could be added that would fine tune the vehicle a little (making it a PID controller). This is probably not needed here though – the guidance system could notice if the vehicle travels somewhere it doesn’t want it to go.

The MDL file for the above is available here.

This is just a very quick first brush analysis, there are much much more things to take into account. The other tilt axis, roll, the need  to actually stay airborne (altitude or vertical velocity feedback loop) that ties into the throttle values too. One could abstract this tilt in one axis to a single control block, and produce another similar block for altitude holding, then couple these blocks into a whole system of altitude and tilt holding (by mixing the throttle values). This should avoid clutter and enable one to isolate problems.

Also, one should add some noise to the sensed angle vs real angle as gyro noise seems to be a real issue for VTVL vehicles. One wouldn’t want to tune a PD controller’s values in a noiseless simulator and then find out it gets wildly out of control in the real world. Even when not simulating noise, one can be quite conservative with the tuning values, and that helps too. The throttles probably would be another source of errors as well, if one used ball valves like here. One could also use pulse width modulated solenoids (John Carmack is fond of those for quick work) and those should be modeled. Digital valves (for liquids) have also improved lately, and hydraulics uses are emerging.

I’ve only done real world PID stuff on lab experiments. But it’s still very cool to see it work. It can balance a ball on an unsteady position on a moving cart, which humans have trouble with using a joystick, and the math in the controller is not complex since linear approximations can be used for that problem.

This post is brought to you courtesy of NaNoWriMo procrastination. I’m feeling overly enthusiastic about a lot of things at the moment, but I really can’t afford to spend time writing about them in any great detail. So here’s the shortlist:

♥ Jennifer’s Body. I’ve seen this movie twice at the cinema now, and if it was still showing, I’d be tempted to go again. It’s a movie that seems to have harvested everything that is relevant to my interests and then served it all up to me on a plate in a beautifully photographed, pop-punk soundtracked, funny and endlessly quotable banquet of awesomeness. I’ll concede that it isn’t a perfect film, and there’s some slightly structural weirdness and awkward pacing, but it’s been a long long time since I’ve seen a horror movie I enjoyed this much.

♥ Michael Marshall Smith. The way Michael Marshall Smith writes makes me want to give up even trying to form words into sentences, or even really doing anything else other than marvelling at how utterly fantastic he is. His writing is also incredibly disturbing and perceptive and brilliant. I just bought a limited edition signed copy of a short story of his from Nightjar Press as a present for my boyfriend, because I’m just that selfless. I even let him read it first.

♥ Lovecraft. I kind of feel like “Lovecraft” is an unfortunate name, because I have to clarify every time I mention them that I’m not talking about Howard Phillips Lovecraft (or indeed the sex shop on Leicester Square). But Lovecraft, the psychedelic Victorian dadaist pop-prog band from Liverpool, are wonderful: their songs are insanely catchy and their videos gloriously deranged. I’ve been playing the songs on their MySpace to death this week.

♥ Pepsi Raw. Officially the tastiest soft drink in existence since Pepsi withdrew Pepsi Max Cino.

♥ NaNoWriMo. Despite the fact that I’m currently writing this instead of working on my novel, I’m loving NaNoWriMo. I’m at 42,000 words right now, which is far further than I’d even hoped to be at this point. My brain seems to have mostly settled into writing every day, and I keep surprising myself with new ideas and twists and character quirks. It hasn’t all been plain sailing – I’ve hit several difficult patches where I couldn’t figure out how to get from where I was to where I needed to be, where characters weren’t co-operating and every plot element seemed trite and uninspired, but although I’m sure that this first draft is utter crap, I’m really enjoying the process.

If you’re doing NaNoWriMo too, add me as a writing buddy!

Things I Love Thursday is the brainchild of Gala Darling.

credit

Inspired by a post on San’s blog and by this blog dedicated to lists I’m doing my TILT this week in the form of various lists. I love lists, I have lists in the back of my daily planner, I have lists on a little note pad I use at work and I even have a notebook with a map of Paris on the front of it that I carry around with me just for writing more lists.

Everyday Activities I Love:

• Showers, both hot and cold (seasonally dependent).
• Riding the Tram.
• Grocery Shopping. No, seriously. I LOVE going to the supermarket. I do it every day. It’s ridiculous.
• Writing ‘To Do’ Lists.
• Painting my nails and getting it perfect.
• Blog reading in the morning.
  

Man-Style I Love:

• Tailored black suits, white shirts and visible tattoos-all together.
• Converse Sneakers, most sneakers.
• Shaved heads gone to stubble.
• Swagger.
• Well fitting clothes, not too tight and not too baggy.
• Personal style.

Jobs I Love to Dream About Having:

• Costume Designer ( See also Garment or Accessories Designer).
• Knick-Knack Store Owner.
• General Arty Type who lives of their creative powers and goes to gallery openings.
• Writer of massive books on fashion history.
• Stationary Designer- in particular diaries, daily planners etc.
• Art Historian

Songs I Love Currently:

• Anything Girl Talk.
• God Only Knows- Beach Boys.
• Jump Around- House Of Pain.
• Perfect Drug and RingFinger, oh anything by Nine Inch Nails
• B.O.B- Outkast
• Happy- Max Sedgely

Words I Love:

• Minutiae
• Squee
• Veritable
• Bonheur (Obviously)
• Dude
• Bon Vivant

Bad Habits I’d Love to Be Rid Of:

• Not cleaning up after myself
• After work beers
• Not exercising enough
• Snacking on creamy biscuits
• Swearing
• Caffeine
  

Historical Figures I Love:

• Marie Antoinette
• Harriette Wilson
• Christian Dior
• Katsushika Hokusai
• Charles Frederick Worth
• Queen Elizabeth the First

Wow!  What a great release – Adobe Flash Player 10.1 / Adobe Flash CS5:

http://www.adobe.com/devnet/logged_in/jchurch_flashplayer10.1.html

SOME NEW FLASH 10.1 FEATURES:

1. Multitouch (Goose)
2. Compute Spectrum on the Microphone (Woodpecker)
3. Accelerometer (Penguin)

FOR PENGUIN TILT AND TRANSLATION CLASSES:

We can now get tilt data from Flash rather than requiring external programs providing the data.  This is great news!

You can use Penguin to emulate tilt while you develop on a PC then plug the actual tilt data in for play on a device with tilt.

Download Penguin Tilt Emulator for Flash and try it out!

All the best!

Desde que a HP fez um comercial inteiro com imagens reais, imitando animacao feita com maquete, varias pessoas tem publicado artigos sobre o assunto. A verdade e que o resultado e super divertido e eu nao resisti e acabei aplicando o efeito em algumas fotos que tirei numa recente viagem. Da uma olhada e veja como as cenas parecem fakes, construidas com maquetes. Clique nas fotos para ver a imagem “Tilt” ampliada.

Il traffico romano vive momenti d’inferno. Il vertice Fao che vede riunite 126 delegazioni straniere, i lavori stradali sulla Tangenziale e in via Nazionale, la protesta degli studenti e degli agricoltori a cavallo di 300 trattori hanno recato un duro colpo al già fragile equilibrio della viabilità urbana. “Il problema della fame è di vitale importanza per milioni di persone”, commenta il vicesegretario per il Lazio dell’Italia dei Valori Oscar Tortosa, che aggiunge: “Purtroppo l’altra faccia della medaglia è la situazione caotica generata da giorni terribili di zone rosse, proteste, cortei, e deviazioni stradali. Roma non può permettersi 2 o 3 manifestazioni al giorno, per quanto ai cittadini debba essere garantito la possibilità di protestare per i propri diritti. L’amministrazione deve stabilire una regolamentazione in merito, affinché gli abitanti della capitale possano convivere con iniziative di varia natura, e non nutrano verso esse un sentimento di indifferenza. Sarebbe, dunque, ancor più dannoso – conclude l’esponente del partito guidato da Antonio Di Pietro -  se le difficoltà di gestione, oltre a danneggiare la vita dei romani, rendessero inutili le ragioni degli scioperi dei lavoratori”.

Spreadable feta; picking out a new bedset (even if I had to pick a new one because the dogs destroyed my last one); catching up on missed episodes of Grey’s Anatomy and Private Practice; being known in my circle of friends as the ‘girl who makes cupcakes’; Julie & Julia (both the book and the movie); playing with eye make-up; sleeping in; decorating for christmas (it’s never too early!!)

cuddling under the blankets on a cool evening; nachos drizzled with ranch dressing; being able to sweaters and not spend the entire day sweating my butt off; hot cocoa mixed with coconut and caramel syrups; hot nuts from the Nut Hut outside the candy store; the movie ‘Up’ and it’s ability to make me cry every damn time I watch it; Christmas music (thank you XM for beginning the holiday stations already); playing board games with good friends; snowflakes falling from the sky (although I would prefer if they tried not to stick please)

 finding out ‘The Hangover’ is being released on the best day of the year – my birthday; planning for Gluttony Day; payday; getting asked to make a wedding cake (even if the asking wasn’t completely serious – it made me feel like a real chef); Secret Santa exchanges; ABC Family’s 25 Days of Christmas – yes, I am excited about watching horrible made for TV Christmas movies; making the decision to finally move – and planning out my new bedroom; buying gifts for friends; mini hot dog pretzels; that the Star Wars Trivial Pursuit game ended before I killed myself or somebody else; The Holiday;  wonderful friends who make me laugh so hard my stomach hurts; and last but not least – quirky tumblr blogs that showcase amazingly cute and funky pictures.

It’s fascinating to rail Durrrr and friends online, but how cool wouldn’t it be to see these games live on TV? We’re about to find out as the Durrrr Million Dollar Challenge goes live.

Matchroom Sport will produce, Sky Sports will broadcast and Full Tilt Poker will sponsor the televised version of the Durrrr Million Dollar Challenge which is about to be filmed at Les Ambassadeurs Club in London, UK, starting next weeek.

Except for the brilliant and fearless Tom “Durrrr” Dwan himself, the show gives us the nosebleed-stakes habitué, crazy Finn Illari “Ziigmund” Sahamies as well as much respected Marcello “Luckexpress” Marigliano, and Sammy “Any Two” George.

Durrrr will play each of these three opponents in headsup cash games for $500,000 each. Blinds are at $500/$1,000 and play goes on for 500 hands of holdem or until one player busts – whichever comes first.

“I am always excited to play my good friend Tom,” said Ziigmund.

“He’s one of the best holdem and PLO players in the world, and when I heard about the challenge I couldn’t wait to sign up. With the gambling, the side-bets, the partying and the drinking in London, this is going to be a whole lot of fun.”

Okay, so here we are, two weeks into NaNoWriMo. And I haven’t even written 3000 words of my NaNo story.

Why? Because Aiden and Callie refuse to talk to me. They sit in the corner like two bumps on a log whispering to each other, but they won’t talk to me…you know, the fucking author! They do give me the finger every so often, so at least they’re acknowledging my existence.

And I’ve tried, really I have. But I don’t know how much longer I can sit and stare at the same Google Doc and not type.

It’s starting to piss me off.

But, you know who is talking to me?

Alice.

Yeah, evil fucking pixie Alice. I LOVE Alice. I love Ashley Greene, too, but that’s a topic for another post.

Still, except for a voice on the phone in Breathe Me and a brief cameo in my Jasper o/s, I don’t write Alice. Why, all of the sudden, is Alice is in my head, demanding that I write a five chapter story for her?!

It’s not like I haven’t been writing. In addition to my 2,800 words of my NaNo story, I’ve written five Breathe Me chapters totaling approximately 15,000 words and 900 words of Alice’s story. I’m going to begin work on my next In The Blood chapter this weekend.

Still, Aiden and Callie are quiet.

It’s all very frustrating.

So, what do I do when I have writer’s block? That’s right, I read stories by people who apparently don’t have writers block. Here’s a few I’d like to recommend:

- I think that lambcullen is my new favorite author. I spent way too much time at work catching up on her story Tides, and then I discovered her new story Tilt. I love Tides, but I LOVE Tilt. You really should read them both.

In Tides, Bella returns to the house she’s inherited from her grandfather and finds her childhood friend Edward living there. She doesn’t know it, but Edward’s been waiting for her…for a long time.

In Tilt, Bella and Edward are both wonderfully awkward and, against their initial wishes, thrown together by a racy Internet personal ad. It’s only three chapters in, and I’m already hooked.

- The Best Man by Bratty-Vamp is a wonderful completed story. In this story, Bella visits home during a college summer break to find out her best friend Jasper is getting married. Jasper, however, can’t decide if Bella or his older brother Edward should be his best man, and he decides a competition is in order. Oh, did I mention that Bella’s loved Edward from afar since she was a kid? Let me warn you: when I thought knew what was going on, something came out of a completely different direction and thwacked me upside the head. I really seriously love this story.

- Red Strings of Fate is an in-progress story by unicornhime told through text messages, emails, and forum posts. Edward meets the girl of his dreams (Bella…of course), but he doesn’t know how to woo her. He looks to a message board to get advice on how to win Bella’s heart. I seriously laughed so hard I cried. The way it’s told is so clever. And, believe it or not, it’s the first T-rated story I’ve ever rec’d.

- The Kübler Ross Model by jadedandboring initially screamed out to me because I am the somewhat proud owner of a completely useless psychology degree. Then I read the first chapter. It is a beautiful, touching story, and I can’t begin to explain how much I love it. Bella has lost the love of her life, and Edward is in a failing relationship. What happens as they begin to find themselves drawn together? The story, currently at 6 chapters, is nearing its end. So, if you’re one that waits for a story to complete, keep your eye on this one.

- Oh, and all you people who encouraged me to re-read the first chapter of Clipped Wings and Inked Armor after getting some sleep (the first time I read it, I just couldn’t get into it), thank you! I love the story, and I drop everything now to read the new chapters.

Now, there are some more stories by my Twitter BFFs that I want to recommend, but I’m saving those for their very own post next week. I think I’ve given you enough to work with for now

(P.S. Keep an eye out for a new post this weekend about my very first giveaway!)

2009-Lamborghini-Blancpain-Super-Trofeo-Front-And-Side-Speed-Tilt-c 1024×768 image wallpaper of 2009-Lamborghini-Blancpain-Super-Trofeo-Front-And-Side-Speed-Tilt-c 1024×768
to view full size click 2009-Lamborghini-Blancpain-Super-Trofeo-Front-And-Side-Speed-Tilt-C 1024X768 image ( 2009-Lamborghini-Blancpain-Super-Trofeo-Front-And-Side-Speed-Tilt-C 1024X768 image )

I played tons of hands yesterday to chase the bonus but I wonder was it worth it? I’ve got less than 100 Summit points to go but at the same time I managed to wipe out 75% of my last week’s winning.

I know that I must treat this as a job but grinding while being tired will do my game no good. I stacked off very light with one pair type of hands A LOT and mistakenly thinking that I could manage the tilt like I did last week. Starting from now, I will be using stopwatch as recommended by spoonitnow to discipline my breaks.

I know what is required to be successful in this game. Again, to remind myself:

1. Make sure all the chores are done.
2. Read ISF Rules to beat low stakes every time before the start of each session.
3. Set the stopwatch to one and half hour.
4. Be DISCIPLINE! Play as PLANNED and find spots to EXPLOIT opponents.
5. Take a 10 minutes break away from the computer. Go to the kitchen and make a drink.
6. Play one more session.
7. Stop and rest.

My best game commence by following these simple steps. The positive money results will follow. It is inevitable.

Pan-And-Tilt Positioner Integrates Electronics

Aerotech has launched a pan-and-tilt positioner with integrated drives and motion controls for high-end camera security, surveillance and defence applications. The APT series includes built-in electronics using the company’s Ensemble MP series of motion controls and brushless servomotor drives for a completely integrated design with top- or side-mount camera bracket and housing mounted connectors for camera, 24-80VDC power and Ethernet control.

A slip ring mounted in the base of the unit transfers power, motor signal and camera connections through the assembly, enabling a continuous 360 rotation of the pan axis and a tilt-axis travel range of +/-95. The overall specification for the standard APT-100 model is position resolution of 7.6 arc seconds and accuracy to 120 arc seconds. Repeatability is 30 arc seconds for bidirectional positioning and 10 arc seconds for unidirectional positioning. Maximum speed in both axes is up to 180 per second. The APT-100 has a 625mm diametrical footprint clearance and an overall height of less than 352mm.

With a payload rating of 35kg, the complete assembly is built for high reliability and low maintenance with a black anodised finish and optional sealing to IP66 ratings for harsh environments. The worm wheel drive mechanism includes a self-adjusting gear preload feature that ensures consistent positioning performance over the life of the product. The standard unit may be application customised for increased tilt-stage travel, increased payload or alternative camera mounting.

Aerotech can provide an inertial stabilisation option, fitting gyroscopes and sensors to maintain ‘line of sight’ when the unit is operated on moving platforms such as aircraft, ships and land vehicles. The version of the company’s Ensemble MP multi-axis motion controller built into the APT-100 has a standard 10/100 Base-T Ethernet port to communicate to a PC or other Ethernet device. The Windows-based Integrated Development Environment software package takes care of setup, programming upload/download, diagnostics and auto-tuning.

The Ensemble may be programmed with Aerotech’s Aerobasic or using Microsoft .Net tools for C#, VB.Net and managed C++ or with Labview VIs. The Ensemble may be permanently connected to a main control system via Ethernet or operate in standalone mode using its complement of digital and analogue I/O for control interfacing.