Analysis and fabrication of a novel MEMS pendulum angular accelerometer with electrostatic actuator feedback

A new type of sensor to directly detect angular acceleration is essential for inertial and control technology. The above interest motivates us to propose a novel micro electromechanical system (MEMS) pendulum angular accelerometer with electrostatic actuator feedback. It adopts a proof pendulum with optimized moment of inertia, suspended to dual anchors by a pair of torsion spring beams, as sensing component. A pair of electrodes are designed as differential capacitors to detect the torsional angular of pendulum, then measure input angular acceleration in sensing axis. Another pair of electrodes are designed as electrostatic actuators for feedback control loop. The structure and operating principle of the MEMS angular accelerometer are introduced. Then, the structure kinetics analysis and signal detecting scheme based on differential capacitors are provided in detail, and the sensitivity and resolution of sensor are derived. Compared with the other MEMS angular accelerometers, the proof pendulum with optimized moment of inertia improves sensitivity and resolution of sensor. The electrostatic actuators feedback loop optimizes the dynamic capability and nonlinearity characteristic. The sensor is fabricated by MEMS fabrication technology. The ANSYS simulation and test results prove the validity of the theoretical analyses. The MEMS angular accelerometer can be used in industrial robots and aircraft by further implementing the signal processing electrocircuit.