In this paper, a novel tuning approach for aggregation operator of a fuzzy PID controller has been proposed. The gamma operator which has a free parameter (gamma) is used for the aggregation purpose. The change of the gamma parameter between 0 and 1 generates the aggregation operator hybrid output of the AND and OR operators. In this manner, firstly, the effect of the gamma parameter change on the control surface of the fuzzy PID controller and the closed loop system response are studied. Secondly, a gamma tuning mechanism is built by a fuzzy logic decision mechanism using the observations from the first various simulation studies. The aim of the gamma tuning mechanism is to change the gamma parameter in an online manner to obtain a fast response with no or less overshoot. The benefit of the proposed approach over the conventional aggregation operator is shown on a non-linear system via simulations. Simulations are performed in Mat lab, and the performance of the proposed approach is studied for a sequence of different set-points in order to observe the set-point following performances. Moreover, the disturbance rejection performance is studied. The results of the simulations show the advantage of the proposed new self-tuning structure over the conventional structures.