The team of researchers at the Cambridge Nanoscience Centre have brought a new approach to the field of resonant sensing, using MEMS technology, which has allowed them to develop small inertial sensors which are expected to be 1000 times more sensitive than current day solutions.
Resonant sensing was first developed in the mid 1960’s, with commercial sensors becoming available about 10 years ago. These sensors respond to changes in the environment by measuring variation in the resonant frequency of the sensor’s mechanical structure. This gives a direct digital output, but can be significantly affected by changes to the ambient temperature and pressure.
The Cambridge team have adapted this approach to use the “vibration localisation effect” discovered by Anderson, and measure the shift in the mode shapes (i.e., the relative amplitude of vibration at resonance) instead. This approach gives an output around 1000 times greater than the traditional methods which is also relatively insensitive to the ambient environment. This allows the sensor to be used to measure inertial forces, acting as an accelerometer or gyroscope.
The method depends on having two microscopic vibrating resonators, linked by a weak elastic coupling spring (that may be mechanical or electrical in nature). It allows an inertial sensor to be produced which is only 2mm x 2mm in size, but with the sensitivity of large sensors that weigh over 10kg.
Accelerometers and gyroscopes are used in many applications and in many different markets, from missiles and aeroplanes, to Wii games consoles. The i-Teams goal is to identify and analyse the best target applications for the new sensors, which make use of their unique combination of high sensitivity, small size and relatively low cost.