Design of an Automatic Control Algorithm for Energy-Efficient ...

12 Controller evaluation
Even though the MUTE car prototype will not be ready before autumn 2011, some testing
was done with the help of simulations. In this way, the functioning of the controller in
combination with the available hardware is shown.
12.1 Hardware-in-the-loop test
The leading institute for the MUTE development, the Lehrstuhl für Fahrzeugtechnik Mün-
chen has built up a hardware-in-the-loop test rig. A special computer simulates the car
and some sensors. This simulation is communicating over CAN-busses 1 with the Mi-
croAutoBox car computer (described in Section 10.7). The actuator and sensor hardware
is directly connected to this box. With this configuration, the interaction of electrics,
hardware control software and the (simulated) car can already be tested. A schematic
drawing of the test rig (showing only the relevant hardware components for the climati-
sation) is found in Figure 12.1.
In this way, tests of the HVAC-unit and first parameterisations were done. One very
important result is the execution time of the optimiser algorithm. Its turnaround time was
measured to be ������ seconds (in the automatic mode). This equals a processor load of
0.09% with the sample time of two seconds. The disturbance estimator also showed a very
short turnaround time of 0.00030 seconds. The remaining control parts are included in
a“��� �”-task because have the same sample time as other blocks in the MUTE software
and can therefore not be regarded separately. This task showed a turnaround time of
0.00028 seconds. As the turnaround times are very low, they showed to be dependent on
the overall system sample time. This is set to 10 milliseconds.
1 Controller-area-network, a standard bus in vehicles.