Design of an Automatic Control Algorithm for Energy-Efficient ...
Design of an Automatic Control Algorithm for Energy-Efficient ...
Design of an Automatic Control Algorithm for Energy-Efficient ...
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12 <strong>Control</strong>ler evaluation 119<br />
be noticed by the passenger.<br />
The results show that the optimiser algorithm is able to come close to the optimum<br />
in 10-20 seconds in the beginning. Even a sudden <strong>an</strong>d comparable big ch<strong>an</strong>ge <strong>of</strong> 5 de-<br />
grees Celsius is tracked quite fast. Other conditions (different temperatures <strong>an</strong>d settings)<br />
showed comparable results. This pro<strong>of</strong>s that the developed algorithm is suitable <strong>for</strong> the<br />
car climate control task.<br />
The population size was set to 10, the number <strong>of</strong> children was 20 <strong>an</strong>d 2 generations<br />
were simulated per run, which has a sample time <strong>of</strong> 2 seconds. A faster convergence c<strong>an</strong><br />
be achieved with higher values, but it requires more resources. The effect <strong>of</strong> <strong>an</strong> evaluation<br />
<strong>of</strong> 10 generations is also shown in Figure 12.2. However, these better results are only<br />
obtained with a more th<strong>an</strong> five times higher computational ef<strong>for</strong>t (cf. Section 8.6.2).<br />
One has to keep in mind that the results above have been obtained without <strong>an</strong>y<br />
parameter optimisation. The adaptive concept, which includes the base population <strong>an</strong>d<br />
the r<strong>an</strong>dom immigr<strong>an</strong>ts, is a trade-<strong>of</strong>f between the ability to track a ch<strong>an</strong>ging environment<br />
<strong>an</strong>d convergence speed which c<strong>an</strong> be adjusted, <strong>for</strong> example by ch<strong>an</strong>ging the number <strong>of</strong> elite<br />
individuals. Even faster reactions may be achieved by adapting the number <strong>of</strong> generations,<br />
children <strong>an</strong>d the population size to fully use the available computing power.<br />
12.3 Simulation test layout<br />
The ability <strong>of</strong> the complete controller to reach the objectives that it was designed <strong>for</strong> is<br />
examined in a computer based simulation using Matlab Simulink. Four models are used<br />
<strong>for</strong> this purpose. The first is the controller, presented in Chapter 11. The same program<br />
as in the car is used, which is possible through its design in Matlab Simulink. It is the<br />
big yellow block on the left side in the simulation model shown in Figure 12.3.<br />
The input values to the control block are filtered by a sensor simulation (or<strong>an</strong>ge,<br />
to the left <strong>of</strong> the controller). Here, the approximated characteristics from the data sheet<br />
are implemented <strong>for</strong> each sensor. The temperature sensors are quite slowly reacting <strong>an</strong>d<br />
have a noise in the magnitude up to one degree Celsius. The humidity sensors are faster<br />
<strong>an</strong>d also have lower noise.<br />
The outputs <strong>of</strong> the controller are fed into a model <strong>of</strong> the HVAC-unit electrics <strong>an</strong>d