<p>This paper investigates a weakly coupled electrostatically driven integrated micromechanical sensor concept for simultaneous sensing of angular velocity and acceleration. Based on the corresponding weakly coupled beam model, a dynamic model incorporating electrostatic nonlinearity is established to describe the effects of coupling strength, axial acceleration, angular velocity, and excitation amplitude on the nonlinear characteristics of the system. Based on analytical calculations and FEM-assisted parametric comparison, a representative set of structural and driving parameters is selected. The multiple-scale method is employed to analyze the amplitude-frequency and force-amplitude response characteristics of the sensor. The influence trends of external excitation, angular velocity, acceleration, and coupling strength on the nonlinear dynamic response of the system are discussed. The analysis results indicate that increasing coupling strength can enhance the response magnitude and the selected sensing-related response feature in the present model, while also introducing additional nonlinear branches. Axial acceleration modifies the hardening or softening behavior of the accelerometer by altering its elongation or contraction state: positive acceleration causes the accelerometer to exhibit stiffness hardening, while negative acceleration leads to stiffness softening within the considered parameter range. The angular-velocity-related and acceleration-related response channels are largely distinguishable under the ideal symmetric assumptions, which suggests the potential of the proposed model for dual-parameter sensing, while further device-level and experimental validation is still required.</p>