Burkhard Kuhlmann

Micromachined Angular Rate Sensors for Automotive Applications

Micromachined angular rate sensors are key elements in several automotive systems, thus enabling highly sophisticated applications like rollover detection and mitigation, navigation systems, electronic stability program, and other future vehicle stabilizing and dynamics control systems. New automotive systems are demanding higher accuracy, better signal-to-noise ratio, higher robustness and insensitivity against external perturbations, better system availability and reliability, as well as easy application of the gyros. This paper is presenting the recent development, now the third generation, of micromachined angular rate sensors at Robert Bosch GmbH. Mass production was started in spring 2005. These surface micromachined gyroscopes exhibit outstanding performance compared to similar designs, especially in term of resolution, noise, and insensitivity against external perturbations

New surface micromachined angular rate sensor for vehicle stabilizing systems in automotive applications

Current developments in vehicle dynamics control systems and future advanced high performance vehicle stabilizing systems demand higher performance of the inertial signals of the vehicles dynamics, especially the angular rate signals: higher accuracy and better signal to noise ratio, high signal refresh rates, higher robustness and insensitivity against external interference, higher system availability and reliability, easier applicability (e.g. additional measuring axes). This paper presents a third generation angular rate sensor cluster MM3.x suitable for high volume production, meeting those demands. Design concepts of the core component - the new angular rate sensor module SMG - are unveiled, giving it outstanding functional performance compared to similar surface micromachined gyroscopes.

100 kHz MEMS Vibratory Gyroscope

The behavior of MEMS rate gyroscopes depends on the sensors resonance frequency f0. Key features like robustness against external vibrations and ease of integration can be optimized by increasing f0. We designed and fabricated a device with f0=100 kHz for experimental and theoretical investigation of MEMS vibratory gyroscopes with increased f0. The frequency of 100 kHz is significantly above the typical f0 of current gyroscopes which is in the range of 10 kHz to 30 kHz. Measurements prove that key parameters that are theoretically derived from a 15 kHz reference model can be scaled to 100 kHz with good accuracy. It is shown that the increase of f0 to 100 kHz has-on the one hand-design trade offs like a much lower sensitivity and higher quadrature and-on the other hand-major advantages like the significantly improved vibration robustness.

A 100 kHz vibratory MEMS rate gyroscope with experimental verification of system model's frequency scaling

The working frequency f0 of vibratory MEMS angular rate sensors is a main optimization parameter. To investigate the specific challenges of increasing f0 we designed a new device with f0=100 kHz. Key parameters of the 100 kHz device are theoretically and experimentally compared with those of a 15 kHz reference sensor. The experimental results show the validity of the theoretical frequency scaling of the key parameters. The measurements show benefits and disadvantages of MEMS vibratory gyroscopes with increased f0>;>;30 kHz.

Noise contributions in a closed-loop MEMS gyroscope for automotive applications

This paper reports on zero-rate noise contributions in a closed-loop MEMS vibratory gyroscope. In particular, we are investigating sources and composition of bias instability noise. This 1/f-noise is the dominant error component when integrating the angular rate for durations on the order of one minute. It is demonstrated that mechanical quadrature is not responsible for the bulk of bias instability noise. We show experimentally that bias instability is strongly dependent on drive loop amplitude and sense mass frequency detuning. Potential sources and cross-coupling paths are discussed.