Developed in response to customers’ desires to manage increased complexity of electronic control units (ECUs) while emphasizing safety and reliability, dSPACE recently released its Offline Simulator—on display at the SAE 2012 World Congress—which can simulate virtual ECUs on a standard PC. By enabling software architects to find and correct implementation errors at an earlier development stage than previously possible, the process becomes easier and much less expensive.
Previously, testing and validation of ECU software designs could not begin until prototype ECUs were available, typically late in the development process. Prototypes are also expensive and cannot be multiplied at will or used in several projects simultaneously.
A virtual ECU (V-ECU)—software that emulates a real ECU in a simulation scenario—comprises components from the application and the basic software and provides functionalities comparable to those of a real ECU. The V-ECU generally has the same software components that will run on the finished ECU, setting it apart from a soft ECU, which uses only a simplified Simulink/Stateflow model. By testing V-ECUs in the dSPACE Offline Simulator, developers are able to investigate real-world issues such as task scheduling, the behavior of the basic software, and communication behavior on a virtual CAN bus.
The number of software components in the large ECU networks installed in many of today’s vehicles can easily reach into the thousands, and because the task of developing ECU components is usually shared by different departments or different suppliers, the software components themselves have to be tested and validated as well as the interactions between them. With Offline Simulator, developers can insert errors deliberately to verify that the system behaves correctly in critical situations. Offline simulation can also be conducted at any stage of the development process.
Offline Simulator provides an integrated tool chain that allows work products such as experiments, tests, and layouts to be applied across the development cycle. The virtual ECUs are handled by ControlDesk Next Generation just like real ECUs; they are described by ASAM A2L files and can be accessed via XCP on Ethernet, with the ECU Interface Module. The Offline Simulator can be applied in both AUTOSAR and non-AUTOSAR context and allows for use of software components in various forms such as c-code, Simulink models, and object code that will enhance collaboration between OEMs and suppliers while helping to retain intellectual property.
The vehicle and component models, usually created with Simulink and used as environment models during offline simulation, can be reused in later development phases. The same applies to the interactive experiment layouts created with ControlDesk Next Generation and to the software verification tests.
Tests can also be designed on a PC and then validated and optimized via offline simulation to save testing time on a hardware-in-the-loop simulator.