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воскресенье, 19 августа 2012 г.

Why Designing a Mars Rover Like Curiosity Just Got a Lot Easier By Tim Maly

MSL Rover NX CAD model







You’ve all seen the artist renditions. This is what Curiosity looks like to an engineer.



A few minutes into our interview last Thursday, I ask Tim Nichols, managing director of Global Aerospace, Defenses and Marine Industries at Siemens, if he was nervous about the Curiosity’s fate on Sunday. “Of course I am,” he says with a laugh, “We all know about missions to Mars — they’re complex.” None moreso than Curiosity’s elaborate landing sequence, designed to get the SUV-sized robot down safely.



He needn’t have worried. Late Sunday night, the rover successfully set down on the Martian landscape, overseen by a tense room of Jet Propulsion Laboratory (JPL) engineers and watched by so many people here on Earth that all of NASA’s websites crashed. Like the rest of us, Nichols was glued to his screen. Unlike the rest of us, Nichols gets to say he had a hand in it. His company’s software designed Curiosity.



Curiosity is much larger than her unexpectedly long-lived predecessors, Spirit and Opportunity. This meant that she couldn’t just land bundled inside airbags like the smaller rovers.



Instead, the mission executed a complex series of maneuvers to eject the robot from its capsule and lower it to the ground, via a rocket-powered sky crane in a sequence of events that NASA called the Seven Minutes of Terror.



Curiosity was designed by the JPL at the California Institute of Technology. When it came time to coordinate the enormous team of designers and engineers that built Curiosity, the capsule, and the sky crane, JPL turned to Siemens. They needed to design the robot (relatively) cheaply and they needed to design it fast — the launch window for missions to Mars comes once every two years. If you miss the deadline, there’s a long wait ahead.
MSL Capsule with Rover NX CAE thermal model







If you squint, you can see Curiosity and the sky crane folded up together in the capsule.



Luckily, Siemens had developed software suited to this sort of project. They call it Product Lifecycle Management (PLM).



One of the costliest parts of creating a new physical product is building and testing prototypes. With PLM’s robust suite of simulators and version tracking, you can avoid a lot of physical prototyping — saving both time and money, and speeding up the development process. In essence, PLM turns the physical engineering of a product into a process that looks more and more like designing code.



PLM runs on a laptop, connected to a central asset manager, called the Team Center. Engineers can check out parts of the project, work on their problems and assignments, and then check it back in to the main branch. This allows for a lot of concurrent design work. “In the past, engineering teams would be somewhat isolated by discipline,” says Nichols, “The overall leadership recognized that they needed to bring all the groups together.”



This is a far cry from past projects, which would be designed as a series of handoffs between teams. First the thermal profiles would be worked out, then the aerodynamics, on down the line. Propagating changes between teams could become a nightmare. PLM changed all of that, Nichols says, giving the team the ability to “compress the schedule and … do many more design iterations.”
MSL NX CAD Exploded view of seperation stages







With luck, this is the only exploded view of the Mars lander that we’ll ever see.



If this sounds a lot like software engineering, especially the open source variety, it’s because it is. There’s a version control system, the ability to check code in and out of the system, and a set of test suites that allow you check the performance of your part of the module in relation to the whole. By keeping the objects in software for as long as possible, you can treat them like software, with all of the speed and flexibility that this implies.



Nichols says their suite of tools has been used to design everything from golf clubs — “Golf clubs are pretty sophisticated, though they haven’t helped my game.” — to aircraft carriers. Looking ahead, he predicts an increasing incidence of distributed international teams of contributors working on a project.
“Global virtual collaboration and engineering is really the future,” he says. “We want to see more of that.”



But first, Curiosity had to make it to Mars. “We all have our fingers crossed,” he said on Thursday. You can uncross them now, Mr Nichols.

суббота, 19 мая 2012 г.

iPhone vs. Android: the Choice is Yours

Androids vs. iPhones. The discussion goes on and on. At the time the iPhone first hit the market, there was really no competition. The iPhone was playing in a class of its own. Early Android phones were dismal: slow UI response, redraw lags, and the overall "do-it-yourself" idea just didn't with consumers.





iphone icons

Today, the situation has changed. With the latest iPhone being a superb device and a wonderful system, the newest Androids leave little to be desired. Today's Androids have no UI lags, offer most of the same apps in the Android Market, and went away with the do-it-yourself, LEGO style approach. Today, picking one system over another is more of a personal preference. Let's try to discover what's good about going the Apple route, and what advantages the Android way can bring.

Hardware and Models

With Apple iPhone, you have a limited choice of only several models. Or, rather, you're limited to just a single current model in several versions that, honestly, differ very little. There are a few older models available from the used market, but that's about it. "You can have any color as long as it's black".

Android phones, on the other hand, come in many shapes, models and colors. Various manufacturers use entirely different hardware. Different screens, processors, memory. Very different quality and usability. Buying an Android phone will require you to do a market research, while you can't go wrong with any current iPhone. Are you a techno geek or a gadget guy? Look for an Android phone you like best. Others will be served by Apple.

Screen

The latest generation of iPhones has a great Retina display. These super high pixel density displays will display your apps, icons and graphics so smooth it's hard to believe. Kudos to Apple: they built one of the greatest screens ever.

Androids ship with all kinds of screens. Some of the better ones can approach iPhones in resolution, but software integration is still lagging. Many apps are still using low-resolution icons and graphics designed to be displayed on lower-resolution screens. When selecting an Android phone, you will have to watch really carefully to get a model with a good screen. If you're not friends with numbers, icon resolutions, angles of view and other specs, just leave the Androids alone.

Pre-Installed Software and UI

An iPhone is an iPhone. They're all the same. One operating system, same UI, the same set of pre-installed apps, exactly the same icons. You can customize it by moving things around and choosing a few icons on your own, but there's only so much you're allowed to do.

Androids are available in many flavors. Different firmware and dozens of OS versions, builds and codenames. Different sets of icons for same apps. Many different shells and launchers. Extensively customizable: you can make Android phones look like whatever you want (and it's not all about custom icons) - but you have to know what you're doing. With such a broad variety, some models are simply better as in simpler to use, more robust and working more reliable than others. If making your very own tailored environment is fun for you, by all means get the Android. If you like it working straight out of the box, get an iPhone and start using it right away.

Maintenance and Upgrades

iPhones don't don't accept memory cards. You'll be stuck forever with the amount of memory you originally got. If you outgrow your iPhone, you'll have to get another iPhone, bringing more money to Apple.

Most but not all Android phones come with a microSD extension slot, allowing you to add more memory when you need it. With microSD cards getting cheaper every year, you will be wealthier in the long run if you buy an Android.

With iPhones, you can't even replace a battery. If your battery goes bad in some years (they all do; lithium batteries die in 3-4 years), you'll be sending your iPhone to Apple for a "major repair" (more dough to Apple), or be on the market for a new iPhone (even more dough to Apple).

While some Android devices use similarly fixed batteries, most devices are easy: just lift the cover and put a new battery in. A new battery will cost a few dollars, allowing you to postpone the purchase of another phone some more years.

Conclusion

Android phones are more affordable to buy and more affordable to upgrade and maintain. They're more extensible and customizable. iPhones are perfect straight out of the box, and offer possibly the best usage experience ever. Which one to pick? The choice is yours.