Abstract: The disclosed devices utilize nonlinearly coupled modes of vibration to provide robust inertial sensors, such as gyroscopes. This actuation mechanism introduces a wider bandwidth in the sense-mode frequency response curve, and consequently enhances robustness to parameter fluctuations due to operating conditions and fabrication imperfections. The vibratory modes of the device are designed to have distinct frequencies where the drive-mode natural frequency is twice the modal frequency of the sense mode. The nonlinear modal interaction due to internal resonance can also be magnified through nonlinearity feedback. The sense mode response can be enhanced in shape, quality factor, and bandwidth by feeding back nonlinear quadratic, cubic, etc. terms.