Edited by Sherri Koucky
One of the most difficult problems faced by military planners is unexpected component or system failures. It's virtually impossible to translate MTBFs for components and systems into a predictive mechanism for whole vehicles.
But, an approach taken by Rymic Systems Inc., Huntsville, Ala., may give maintenance experts enough information to predict failure in individual vehicles. Moreover, the technique may work equally well in the civilian sector.
Rymic Systems Enternet Appliance design blends inexpensive Internet platforms with custom ICs to acquire and display data. Maintenance specialists can view, download, and analyze details about engine operation, oil pressure, battery status, and other important qualities. They can quickly compare measurements with norms to identify conditions that might be precursors to failure.
Military applications have a reputation for being quite demanding. So it's difficult to imagine such equipment built largely with an off-theshelf heritage. Yet Enternet now serves on battle tanks and other combat vehicles. Maintenance specialists establish TCP/IP connections with the vehicles to download operational data. The device can even send e-mail to maintenance personnel, alerting them of problems requiring attention. The TCP/IP approach requires no expensive diagnostic systems or depot-level facilities. A simple browser-based interface makes it easy and reliable.
Currently, it is in the prototype stage and costs about $5,000. The goal is to reduce manufactured cost to $1,000 per unit.
Rymic soon expects to have prototypes ready for Army testing. They will go on the palletized loading system, heavy expandedmobility tactical trucks, and the Bradley fighting vehicle.
Platform design considerations
Enternet connects to the existing signal buses on a vehicle through either serial I/O or Ethernet. It is basically an onboard Web server and uses Internet protocols. Data streams from engine and system readouts to the Enternet box, which generates Web pages displaying the data.
Use of accepted industry standards keeps component costs low and makes the system inexpensive to operate. Most off-the-shelf equipment is second sourced, so design-tostandards doesn't lock in specific components, letting design take a "best of breed" approach.
Use of standards is doubly important in embedded data acquisition, communications, and display. Today, Internet technologies are almost a given in any sort of communications equipment, even embedded applications. In the case of Enternet, initial Army requirements didn't justify either the up-front cost or development time for devising a custom ASIC design.
Commercial ASIC technology has progressed to the point where the standard architecture of the PC can sit on the same chip as the network and bus.
At 4 X 6 X 4 in., Enternet sits in a package that easily works in with standard vehicle features. Its small profile bodes well for future use.
At the heart of Enternet is NetSilicon's Net+Arm, a 32-bit Ethernet-enabled microprocessor. The Net+Arm combines some of the best qualities of the PC and ASIC approach. It forms the core of a tightly integrated platform including hardware, operating system, and all networking software. It also includes a 10/100 Ethernet MAC interface, integrated cache, memory controllers, a bus controller, timer and clock generator, and I/O.
This platform is as reliable as off-the-shelf processors and costs about as much. But it performs much like custom designed and highly integrated ASICs. Network protocols are built in, as are standard Web applications such as HTTP, Internet mail protocols, SNMP, and FTP.
Enternet uses a complete embedded Linux platform that integrates all hardware, software, and development tools. UClinux, a version of Linux that runs on processors with no memory management unit (MMU), supports open-source applications including Web servers, mail clients, and FTP clients.
NetSilicon partnered with Red Hat Inc., Raleigh, N.C., to port uClinux to the platform and provide ongoing technical support to customers. Using standard Linux APIs along with established interfaces simplifies the task of developing software.
One additional benefit of Enternet technology is that it can monitor a large number of systems and components. This means that large vehicles such as tractor-trailer trucks, earthmovers, and construction cranes are all potential beneficiaries.