Biaxial Angular Acceleration Sensor with Rotational-Symmetric Spiral Channels and MEMS Piezoresistive Cantilevers

Angular acceleration sensors are attracting attention as sensors for monitoring rotational vibration. Many angular acceleration sensors have been developed; however, multiaxis measurement is still in a challenging stage. In this study, we propose a biaxial angular acceleration sensor with two uniaxial sensor units arranged orthogonally. The sensor units consist of two rotational-symmetric spiral channels and microelectromechanical system (MEMS) piezoresistive cantilevers. The cantilever is placed to interrupt the flow at the junctions of parallelly aligned spirals in each channel. When two cantilevers are used as the resistance of the bridge circuit in the two-gauge method, the rotational-symmetric spiral channels enhance the sensitivity in the target axis, while the nontarget axis sensitivities are canceled. The fabricated device responds with approximately constant sensitivity from 1 to 15 Hz, with a value of 3.86 × 10−5/(rad/s2), which is equal to the theoretical value. The nontarget axis sensitivity is approximately 1/400 of the target axis sensitivity. In addition, we demonstrate that each unit responds according to the tilt angle when the device is tilted along the two corresponding rotational axis planes. Thus, it is concluded that the developed device realizes biaxial angular acceleration measurement with low crosstalk.

Atomic force microscope with an adjustable probe direction and piezoresistive cantilevers operated in tapping-mode / Im Tapping-Modus betriebenes Rasterkraftmikroskop mit einstellbarer Antastrichtung und piezoresistiven Cantilevern

This article presents a new tilting atomic force microscope (AFM) with an adjustable probe direction and piezoresistive cantilever operated in tapping-mode. The AFM is based on two rotational axes, which enable the adjustment of the probe direction to cover a complete hemisphere. The whole setup is integrated into a nano measuring machine (NMM-1) and the metrological traceability of the piezoresistive cantilever is warranted by in situ calibration on the NMM-1. To demonstrate the capabilities of the tilting AFM, measurements were conducted on a step height standard.