Design and Implementation of a Real-Time Interface

Background

In our ongoing research project Real-Time Computing on Multicore Computers, we have developed a proof-of-concept for the execution of hard real-time code on one core of a multicore x86 processor. The main idea is to shield a process from task switches, interrupts and unpredictable system call latencies with as least modifications to the operating system as possible. This comes at the cost of avoiding system calls which inhibits all common means of inter-process-communication (IPC). To fix this issue, typical IPC primitives (e.g. semaphore, message queue) based on shared memory and spin-locks are provided.

To connect the logical control code to the real world, specialized interfaces are needed. Different approaches should be evaluated prior or at the beginning of the work. Especially the latency, the bandwidth and the programmability must be accounted for. Possible interfaces are serial and parallel ports (less common today and too slow), USB, PCIe to digital IO boards, and others.

To evaluate the software architecture beyond micro benchmarks, a real-world application should be implemented. One imaginable demonstration is an engine control unit (ECU). The input of the angle of the crankshaft and the output of ignition signals and fuel injection are extremely time critical and should be controlled by a hard real-time task. Other values controlling the engine's conditions (pressure, temperature, knock) must be considered also, but are sufficient in soft real-time. Finally, the reference input (throttle) and the optimization of the working point are less, but still time critical.

Other possible applications:

• roboter control (hard real-time: movement control, soft real-time: path planning)
• machine control, e.g. milling cutter (x,y(,z) movement, intersection control, ...)

Assingment

• Selection of real-world interface
• Implementation of hard real-time capable driver
• Design and Implementation of the software
• Extension and Improvement of IPC algorithms
• Evaluation

We offer

• Comfortable working-environment, as well as a good equipped Computer infrastructure
• Personal and engaged supervision
• This work can be realised externaly on request (e.g. if simulation hardware is available)

Profil of requirements

• Intermediate diploma of Electro- and Informationstechnics or (technical) computer science
• Alternatively the according prerequisites for a Master's thesis
• Good programming skills in C/C++
• Understanding of operating system internals and system programming
• Linux experience recommended
• Competence to work autonomous and creative

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