Rockwell Science Center

Return to Aerospace/Defense List

Contact:
Rockwell Science Center
P.O. Box 1085
Thousand Oaks, CA 91358

Tools Used:
Allegro ORBLink, CORBAŽ

Description:
When the Rockwell Science Center Palo Alto Laboratory (RPAL), a branch of the Rockwell Science Center, design research team created their Design Sheet application several years ago, they knew they had designed a powerful application. Rockwell engineers use Design Sheet, a conceptual design environment which facilitates tradeoff studies in the early stages of design, for complex systems such as aircraft, launch vehicles, and defense systems. The application uses constraint management techniques, symbolic mathematics and robust equation solving capabilities to represent conceptual models in the form of mathematical equations.

Although Design Sheet had proven very successful with practical conceptual design analysis problems, the team knew the application could be even more effective if it interacted and worked in conjunction with variety of other programs.

Rockwell engineers still needed to integrate Design Sheet, which is written in Common Lisp, with other applications written in different languages such as C, C++, Java and Visual Basic. CORBA was selected (in 1996) as the communication link because it provided a standard API and could support any platform and any application. There were no commercial ORBs, however, that supported Common Lisp (there was no standard for CORBA mapping for Common Lisp). The team started by building a Lisp/C++ bridge to export Design Sheet functionality through a C++ ORB. This solution worked well, except that it was cumbersome to maintain.

Then Franz Inc.'s Allegro ORBLink, a CORBA-conformant LISP ORB, became available and their problems were solved. JC Reddy, a research scientist at Rockwell, was amazed at how quickly Franz was able to create their ORBLink product, "Just last year Franz was writing specifications as to what the product should be. Now, one year later it's here and it works well."

"It's well supported too," he adds. "Franz is very responsive to problems, and we receive good fixes." In addition to being a robust ORB, Reddy says that it contains nearly all of the functionality Rockwell needed. He also approves of the Lisp mapping and says that it has been done in a natural and effective manner.

To date, Reddy's group has completed the CORBA API portion of Design Sheet, and is working on the applications, which will enable it to communicate with other design tools and databases. A prototype Java GUI (a client) has been developed which communicates with Design Sheet through CORBA. Using this GUI, many designers can simultaneously work with Design Sheet models. He also predicts Design Sheet soon will be able to interact with applications such as Visual Basic and Excel, either through CORBA or through native OLE support provided by Allegro CL.

The benefit of CORBA and Allegro ORBLink is that it enables developers to use the programming language of their choice, selecting the language that best meets the objectives of the application. Reddy, who is relatively new to programming in Lisp, says, "Lisp is very flexible and fast-especially when building prototypes." He also likes the dynamic runtime feature of Lisp . "We can run, compile and deploy programs on the fly, and it's easy to use," he says. "This would be very difficult to do in C++ or another language."