German traffic lights powered by Linux and real-time Java

A Greman vendor of city-wide traffic management systems is converting its flagship traffic light controller to Linux and real-time Java.

Right Now, Signalbau Huber’s Actros controller is based on Debian GNU/Linux 3.2. The Versions based on the new software implementation are expected to begin testing by year’s end, according to Joachim Lock, R&D engineer. “The migration will enable us to move from several different CPUs to one CPU, keeping security-critical functions and Linux separated,” he stated

Signalbau Huber is one of Germany’s two largest traffic managment system vendors. He pointed out the company’s systems are used in Frankfurt, Stuttgart, Prague, Budapest, Vienna, Poland, Warsaw, and Benelux, among other European locations.

A single Actros controller can control 196 individual signals

1. The Actros controller runs Linux on a single x86-compatible control-plane processor.
2. A CAN (controller area network) backplane supports multiple switching card modules, each based on an Infineon XC164 microcontroller.
3. The switching cards use MOSFETs (metal-oxide semiconductor field-effect transistor) to send voltages to connected signals — including pedestrian and traffic lights.
4. With a full complement of switching cards, a single Actros controller can control 196 individual signals, Lock said.

Signalbau Huber traffic management system architecture

Signalbau Huber’s current, Debian 3.0-based Actros controller uses an AMD SC520 “control processor” clocked at 133MHz. It also has a “security processor” that will be obviated by the new ELinOS/PERC architecture. The company has not yet finalized its choice ofprocessors for next-generation Actros controllers.

The new design’s control processor will run Sysgo’s ELinos 4.1 embedded Linux implementation, including PikeOS, Sysgo’s real-time, POSIX-compatible execution environment add-on.

The Linux component will provide a browser-based management interface accessible over the network or to on-site technicians.

The real-time PikeOS environment, meanwhile, will host Aonix’s PERC real-time Java component.

Two safety-critical applications will run under PERC. The first of these real-time Java applications is a traffic control program specific to each intersection, enabling engineers to program light behavior in Java. The second is an OCIT (open communication interface for road traffic control systems) networking stack that handles most communications with the central management system.

Lock added. “By selecteing Linux, they are prepared for the future. It’s a flexible and scalable system.” Good Luck Guys..

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