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11.2. Platform Specific Model for the Simulation
stimulations
modes, transitions
Simulation Traces EVC
modes, transitions
ETCS outputs
Figure 11.3.: Data flow of the generation of traces for Modes and transitions
Req.14: simulation of the physical behaviour of the train
Req.15: access to DMI inputs and outputs
Req.13 The simulative PSM must be developed using the already proposed platform-specific
adaptor stubs in Figure 8.18 to make it directly usable for any openETCS model / CIM.
Thus, those stubs or rather their methods only have to be implemented with the simulative
functionality by class inheritance.
Req.14 Since the simulation uses no hardware components, the physical behaviour must be
simulated, too. This means, for example, if a brake system (service or emergency) is applied, the
resulting output value of the odometer should be modified in a physically meaningful manner.
Therefore, a physical model for the train movement and for brakes must be implemented in
the simulative PSM.
Req.15 Corresponding to Figure 11.1, the simulation does not only need access to hardware
interfaces in the PSM because the driver’s behaviour should be modelled by manipulating inputs
of the DMI. Furthermore, DMI outputs must be used to trace the state and the behaviour of
the EVC binary, as it is defined in Figure 11.3. Therefore, an additional interface for accessing
the DMI via D-Bus has to be defined and implemented.
11.2.1. Structural Design
According to Req.13, the simulative PSM should implement the provided adaptor stubs. This
is done by inheritance from the stub classes, as it is shown in the UML class diagram in
Figure 11.4. For simplification, all class names used in this section refer to the simulative
classes in the ::oETCS::DF::PS::SIM UML package. The physical model of the train is located
in the CServiceBrake class, which uses a separated thread for the permanent calculation.
This is indicated by the composition m_pPhysicalCalculation to the ::std::thread class. The
COdomoter class holds – due to its derivation from the stub class in the PS package – the
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