Tiny accelerometers integrated in aircraft wings
Being the most ambitious aeronautical research programme ever launched in Europe, Clean Sky intends to speed up technological breakthrough developments and shorten the time to market for new and cleaner solutions tested on full-scale demonstrators. Speeding up new aviation designs to significantly increase the environmental performance of aeroplanes and air transport requires innovation on all parts of the aircraft. Within the EU-funded project MICRO-IMU, researchers worked to design an application-specific integrated circuit (ASIC), a microchip for hosting microelectromechanical system accelerometers. Researchers combined several functional blocks on a single chip. The main components of the digital to analogue converter and multiplexer block were the switches that were necessary to excite the outer sensor electrodes. Tailored transistors were implemented into the switches to ensure stable behaviour over the whole voltage range. The integrated charge amplifier was used to produce a voltage output proportional to the integrated value of the input current. Another integrated element was the thermal probe used for measuring the precise chip temperature. The value is digitised and stored in a register. According to the specifications, the temperature range covers between – 55 and + 110 °C. The reference block was another main block of the ASIC. Very high and precise voltage references are essential for the operation of analogue to digital converters (ADCs), the charge amplifier and the temperature probe. An external reference source was used, whereas the derived voltages can be trimmed through the serial interface to compensate offset errors of the amplifiers. The ASIC has two interfaces for communication. Because of the high data rates and real-time computing, the first serial interface is only used for transmission of the acceleration data, whereas the second interface serves for the read-out of the measured temperature, and for writing the configuration and adjustment register. To avoid interference between the ADCs, each one has its own references, which can be trimmed separately. These highly compact and lightweight sensors are expected to be integrated into aircraft wings. With their participation in the Clean Sky programme, MICRO-IMU contributes to speeding up new and greener aviation designs to protect our environment.
Keywords
Accelerometers, aircraft wings, inertial measurement unit, MICRO-IMU, application-specific integrated circuit
