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Figure 16 Simulations of the control algorithm’s behaviour with a constant optimum value for the control-signal. Two different sets of  u and  t was used.

The scenario shown in Figure 16 could also be regarded as a system without any disturbances. Since the algorithm only responds to variations, it could be regarded as a high-pass filter, and thus the effect of a constant  would simply be filtered away (except for the fact that it changed the optimum of the control-signal). Regarded from this point of view, the control algorithm could be said to work well when there were no disturbances on the system. when  was varied slowly, as in the simulation shown in Figure 17 where  was assumed to the sum of a constant and a low-frequency sine-signal, the control-signal followed the optimum well. This scenario could also be regarded as a disturbance around a constant optimum. From this point of view the simulation showed that the controller was sensitive to large disturbances.