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.

The Release of Large Menu Icons

Menu-Icons.com announces the release of Large Menu Icons, a royalty-free library of stock menu images for application developers and web designers. The new set includes 398 icons drawn in matching style, color and gamut. The Large Menu Icons collection sells for $49.00.


About Large Menu Icons


Large Menu Icons is the perfect choice for busy application and Web site developers. This collection of stock icons with matching properties such as style and colors, can be used in various projects and scripts, as well as on portals, blogs, forums, and web sites. Large Menu Icons will make an application, blog or applet look modern and consistent throughout. All icons in the Large Menu Icons collection are royalty-free. The entire collection is immediately available and comes with an online preview.


What's Inside


The Large Menu Icons collection contains images representing all sides of the application work. Some of the icons in the set are: open, close, edit, validate, time, clock, error, OK, data, computer, archive, people, user, girl, man, admin, horse, car and more.


Large Menu Icons


Technically, the set includes icons in a number of formats, sizes, color resolutions, and image styles. Every icon from the library comes in sizes of 16x16, 24x24, 32x32, 48x48 and 64x64 pixels. Normal, disabled, and highlighted versions are included for every icon. 256-color and semi-transparent True Color icons are supplied. Large Menu Icons are delivered in Windows Icon (ICO), Bitmap (BMP), GIF and PNG formats for instant integration into any systems. The entire Large Menu Icons collection is available for only $49.00. Source images are also available in SVG and AI formats for an additional payment.


Menu-Icons.com also plans to release a number of new original icon sets including Lumina Menu Icons, Windows Menu Icons, New Menu Icons, Cool Menu Icons, Win8 menu Icons, Vista Menu Icons, Mac Menu Icons, Android Tab Icons, Linux Menu Icons, Nokia Menu Icons, iPhone Menu Icons, Mobile Menu Icons.


About the Company


Menu-Icons.com offers thousands of icons in the most difficult small resolutions. PDA and mobile developers and designers can enhance their software with smooth, perfectly rendered icons in the most convenient resolutions. Menu-Icons.com are available in all sizes common to desktop and mobile applications for mobile phones, communicators, and desktop applications. All icons offered by Menu Icons are royalty-free, ready-made and instantly available.