In pursuit of extremely sensitive sensors, the dimensions of these sensors get smaller and smaller. Small scale resonators are commonly used as sensors by relating changes in the dynamic behaviour to a sensed quantity. Conventionally, the dynamics used for sensing are in the linear regime. But at smaller scales the dynamic range of the linear regime decreases. Therefore, it is of interest to investigate the dynamic behaviour in the nonlinear regime, as with the decreasing scale of the resonators this becomes inevitable. Especially, little is known about the frequency stability in this region. The frequency stability is an indication for the potential sensitivity that the resonator can have as sensor. By using phase locked loop (PLL) the frequency stability around the resonance frequency of nonlinear resonators can be obtained. This research contains attempts to control multilayer graphene drums around its fundamental resonance frequency with PLL. In addition, the frequency stability at these points are presented by measure of the Allan deviation. There are roughly two different distributions of the frequency stability over the frequency response obtained. One resonator shows behaviour attributed to internal resonance. This internal resonance is linked to an increase of nonlinear damping. Combining that with a simple simulation model, a relation was found between increased nonlinear damping and an improvement of frequency stability.