As international tour guide Nia Vardalos said in My Life in Ruins, "Australian people are the nicest people anywhere, but you just can't understand them."
How much PID does it take for the F-35 Lightning to do what it does?
Haven't been to an airshow in year's, depending on the participants the next Cleveland event may see me there.
That extreme transonic vortex is somthing to behold.
Transonic flow:
The term Transonic refers to a range of flow velocities just below and above the localspeed of sound (generally taken as Mach0.8–1.2). It is defined as the range of speeds between the critical Mach number, when some parts of the airflow over an aircraft become supersonic, and a higher speed, typically near Mach 1.2, when all of the airflow is supersonic. Between these speeds, some of the airflow is supersonic, while some of the airflow is not supersonic.
No idea about the F-35. But if you want an idea of some of the problems solved in the Apollo's guidance, navigation, and control systems check out this nice presentation by Dr. William Widnall of MIT.
From which we learn the amazing fact that they did not use quaternions in their calculations like we do on quad copters now a days. So the Apollo vehicles had to be careful not to get into gimble lock. Although I guess that may have been more to do with the mechanical gyros they used than the calculations.
River Piddle, a river in Dorset, England
A slang term for urine and urination
Piddle Brook, a watercourse in Worcestershire, England
Piddles, a character in the video game Banjo-Kazooie: Nuts & Bolts
Pathetically trivial and trifling as in piddling little questions
There is also a village called "Wyre Piddle" in Worcestershire. It's on the river Avon where it joins the Piddle Brook.
They have a local beer there called 'Piddle in The Hole'.
It's quite a freaky place.
I'm glad not to be under your PIDler on the roof.
I'm happy not to be living down river from the village.
But then there is supposedly a must read book about that by a Mr. Freeley.
Highly-stealth aircraft like the F-117 Nighthawk are aerodynamically unstable in all three aircraft principal axes and require constant flight corrections from a fly-by-wire (FBW) flight system to maintain controlled flight.
The United States Defense Advanced Research Projects Agency (DARPA) awarded Northrop Grumman a $10.3 million (USD) contract for risk reduction and preliminary planning for an X-plane OFW demonstrator,[6] known as the Switchblade. That program was eventually cancelled, citing difficulties with control systems.
Even the Boeing 777 is pretty unstable. I'm told it is possible to fly it with all digital Fly By Wire turned off. just using the backup analogue control, but that it is very hard work for the pilot.
Of course the Concord was the first passenger aircraft with fly-by-wire controls, all done with opamps !
Interestingly I just learned that some important control algorithms for the Apollo Lunar module were gleaned from papers published by Russian academics at the time...
I got my girls a floating mag-lev globe for Christmas, which reminds me how former students of mine often joked that I subjected them to "cruel and unusual punishment" in some of my class requirements. In addition to programming BASIC Stamps, they had to build a magnetic levitator. Pretty simple stuff, they had to (learn to) solder up an LM339 comparator circuit, which simply switched on/off (via power transistor) an overhead electromagnet when the permanent magnet on the floating item underneath broke an IR beam. Used two 9V batteries, one for the circuit and one for the electromagnet. Man, how they burned through 9V batteries. If the floating object fell off, the electromagnet just stayed on and drained thar 9V battery down to nothing. Not a lot of amp-hour capacity there.
I provided some strong flat neodymium magnets, and students were free to select any small object they wanted to levitate, which was generally one of the many dead 9V batteries they consumed in the course of the project. This minimal control system had no electronic P, I, or D but it just barely worked. It required careful mechanical adjustment and mechanical damping. We used foam earplugs (AKA slow recovery foam) between the magnet and object (9V battery). You could feel the whole system vibrate when it was working properly and it absolutely would not work without the foam damper. A simple, cheap demonstration of dynamic mechanical damping in action.
Comments
As international tour guide Nia Vardalos said in My Life in Ruins, "Australian people are the nicest people anywhere, but you just can't understand them."
Some yankee females have a growl in their voice that gets anoying.
EDIT: I believe that started in Silicon Valley where the "Valley Girl" came from.
Haven't been to an airshow in year's, depending on the participants the next Cleveland event may see me there.
That extreme transonic vortex is somthing to behold.
Just a piddance.
What a great name for a robot, creativity must be in your blood.
From which we learn the amazing fact that they did not use quaternions in their calculations like we do on quad copters now a days. So the Apollo vehicles had to be careful not to get into gimble lock. Although I guess that may have been more to do with the mechanical gyros they used than the calculations.
I think I'm calling my robot the Pidler
Don't call us if it happens to get stuck on the roof.
Here is a new product just begging for erco's expertise. They call it a climber cart, but it's not motorized.. .yet
Piddle
From Wikipedia, the free encyclopedia
Piddle may refer to:
River Piddle, a river in Dorset, England
A slang term for urine and urination
Piddle Brook, a watercourse in Worcestershire, England
Piddles, a character in the video game Banjo-Kazooie: Nuts & Bolts
Pathetically trivial and trifling as in piddling little questions
They have a local beer there called 'Piddle in The Hole'.
It's quite a freaky place.
"Piddles" has been used as a kind of generic name for any young cat. Can't think why.
I have to make sure my pidler can hold it's PID.
I'm glad not to be under your PIDler on the roof.
I'm happy not to be living down river from the village.
But then there is supposedly a must read book about that by a Mr. Freeley.
You haven't heard that one?
The Chinese author who wrote the book "Yellow River by I. P. Freeley".
I'll refrain from telling the one about Mike Hunt.
Maybe you had better PM that one. If that isn't appropriate then send it to me in a plain brown envelope.
PID has got to be a major factor here, with all of these actuators and other things to control. The pilot still has to concentrate on flying.
Yup, and that's a fairly conventional airframe. Funkier airframes require funkier FBW control systems.
From https://en.wikipedia.org/wiki/Lockheed_F-117_Nighthawk
Highly-stealth aircraft like the F-117 Nighthawk are aerodynamically unstable in all three aircraft principal axes and require constant flight corrections from a fly-by-wire (FBW) flight system to maintain controlled flight.
Further exacerbating instability & control issues are planes with forward swept wings (X-29) or oblique wings:
The United States Defense Advanced Research Projects Agency (DARPA) awarded Northrop Grumman a $10.3 million (USD) contract for risk reduction and preliminary planning for an X-plane OFW demonstrator,[6] known as the Switchblade. That program was eventually cancelled, citing difficulties with control systems.
All about flight control systems: https://wuecampus2.uni-wuerzburg.de/moodle/pluginfile.php/563915/mod_resource/content/1/FlightControlLecture_UWB_2015-comments-sm.pdf
Of course the Concord was the first passenger aircraft with fly-by-wire controls, all done with opamps !
Interestingly I just learned that some important control algorithms for the Apollo Lunar module were gleaned from papers published by Russian academics at the time...
President Elect says the price of the F-35 is out of control.
http://nytimes.com/2016/12/12/us/politics/trump-f35-fighter-jet-tweet.html?
Read instructions carefully!
I provided some strong flat neodymium magnets, and students were free to select any small object they wanted to levitate, which was generally one of the many dead 9V batteries they consumed in the course of the project. This minimal control system had no electronic P, I, or D but it just barely worked. It required careful mechanical adjustment and mechanical damping. We used foam earplugs (AKA slow recovery foam) between the magnet and object (9V battery). You could feel the whole system vibrate when it was working properly and it absolutely would not work without the foam damper. A simple, cheap demonstration of dynamic mechanical damping in action.