Software in the Loop Simulation
We support setup, integration, application and maintenance of your 'Software in the Loop' simulation environment for the development of control software for mechatronic products.
Challenge
Control software governs the behavior of the mechatronic hardware (mechanics, hydraulics, electrics, ...) of mechatronic systems. Experience shows, a tight integration of development and validation is crucial for the efficient development of high-quality control software. With an increasing complexity of module interactions, the importance of early and comprehensive system-level testing increases, because: bugs on system-level are now more likely, more costly to fix, and harder to find. Testing before physical prototypes exist, for both controllers and hardware, is one necessary step towards early system-level testing. Testing based solely on HiL (Hardware in the Loop) and physical prototypes is limited: occurrs relatively late, it is expensive, has slow turn around times, and provides in practice only quite limited coverage.
Idea: Software in the Loop
To provide the control software engineers with the means to easily run versions of the control software on their laptops or PCs using simulated mechatronic hardware. For an overview of how SiL can be embedded in the mechatronic development process, you can have a look at the following presentation (presented at the International VDI Congress Transmissions in Vehicles 2009 in Friedrichshafen, Germany).
Benefit for the design process
- Early detection of bugs and design flaws, especially in the control software
- Dimensioning, application, and optimization of control software parameters. As a result, more mature designs are transferred to later design and test stages, e.g. HiL, test rig and on-road trials
- Powerful debugging and analysis: External debuggers, such as Microsoft Visual Studio, can be connected for step-by-step code evaluation. Arbitrary signals and state variables can be easily investigated in SiL. The reaction of the system to certain faults can in some cases be investigated only in a SiL simulated environment - for instance due to safety hasards or due to the costs of assembly distruction.
- Agility: HiL facilities are typically limited and expensive resources. Moreover, the process chain from the developer's laptop to the ECU in the HiL is relatively long. This results in unwanted delay (up to several days) between development of control software and HiL test. In a SiL environment, there are virtually no delays.
- No real-time requirements: As opposed to HiL, SiL-based testing does not require that the plant is simulated in real-time. One benefit of lifting this requiremets is that, when using relatively simple models, the simulation in SiL can run many times faster than real time. This allows comprehensive logic tests with fast turn-around to be conducted. Another benefit is that, detailed simulation models that are slower than real time, but that are absolutely necessary for investigating relevant system properties, can be used without limitations in SiL. This enables new applications such as simulation-based dimensioning, optimization, and application of a mechatronic system, including failure simulation and validation of function quality based on one and the same model.
- Coverage and cost: Because of the above limitations, many tests are not or cannot be conducted on HiL. This means that many bugs remain undetected until very late development phases or until the products get to the market. SiL testing, viewed as a HiL complement, can sinificantly improve this situation.