Application-specific codesign platform generation for digital mockups in cyber-physical systems

Abstract

The testing of cyber-physical systems requires validating device functionality for a wide range of operating conditions. The environment with which the cyber-physical device interacts, such as lungs for a medical ventilator device or a busy freeway for an autonomous vehicle, may be complex and subsequently difficult to explore all possible configurations. Computer simulations that utilize device and environment behavioral models may be used as a first stage of testing, but at some point development must occur using the real device running in real-time. We present a codesign framework for aiding cyber-physical device development where real devices or prototypes are connected to real-time models that simulate the interacting environment. Such test setups are known as digital mockups and allow for testing environment scenarios that are hard to capture with commonly-used but limited physical mockups. The framework supports model hardware/software codesign to enable models of varying speed and accuracy to be implemented within an embedded processor or as a custom coprocessor circuit on an FPGA. We describe an accompanying tool that generates code templates to reduce the time required to develop digital mockup test setups. We utilize the framework to build a digital mockup test setup for a commercial ventilator, and showcase codesign capabilities by implementing environmental models as both circuits and as instructions on a processor.

MEDS: Mockup Electronic Data Sheets for automated testing of cyber-physical systems using digital mockups

“…Digital Mockup architecture has been previously proposed [12]. The MEDS content is stored within a memory block on the FPGA.…”

Synthesis of custom networks of heterogeneous processing elements for complex physical system emulation

“…We consider the minimal required components for each platform in order to performance the emulation. The approximate cost of each platform is as follows: size and the flexibility to build custom interfaces to the physical world [17].…”

Digital mockups for the testing of a medical ventilator

“…Sirowy [15] introduced the transducer bypass method to facilitate communication between device and model. Miller presented a framework for building codesigned hardware/software digital mockup architectures [11].…”

“…For our current implementation, we utilize a Xilinx Virtex5 FPGA to host a circuit synthesized via the Xilinx XST tool chain [17]. We use a previously described tool [11] to generate the digital mockup framework prior to synthesis. Using an FPGA is not a requirement for the framework, as less complex models may meet real-time constraints on a desktop computer.…”

“…Physical mockups provide a simple mechanism for testing a system, but lack the sophistication to capture more complex physical system phenomena. A more thorough method of testing uses digital mockups [11] [15], in which a mathematical model of the environment interacts directly with the device's computers, bypassing transducers, to stress device functionality. A digital mockup benefit is the flexibility to capture a broad range of environmental scenarios not always possible when using a physical mockup.…”