Novel concept of a single-mass adaptively controlled triaxial angular rate sensor

Abstract

This paper presents a novel concept for an adaptively controlled triaxial angular rate (AR) sensor device that is able to detect rotation in three orthogonal axes, using a single vibrating mass. Pedestrian navigation is presented as an example demonstrating the suitability of the proposed device to the requirements of emerging applications. The adaptive controller performs various functions. It updates estimates of all stiffness error, damping and input rotation parameters in real time, removing the need for any offline calibration stages. The parameter estimates are used in feedforward control to cancel out their otherwise erroneous effects, including zero-rate output. The controller also drives the mass along a controlled oscillation trajectory, removing the need for additional drive control. Finally, the output of the device is simply an estimate of input rotation, removing the need for additional demodulation normally used for vibratory AR sensors. To enable all unknown parameter estimates to converge to their true values, the necessary model trajectory is shown to be a three-dimensional Lissajous pattern. A modified trajectory algorithm is presented that aims to reduce errors due to discretization of the continuous time system. Simulation results are presented to verify the operation of the adaptive controller. A finite-element modal analysis of a preliminary structural design is presented. It shows a micro electro mechanical systems realizable design having modal shapes and frequencies suitable for implementing the presented adaptive controller.

On Control System Design for the Conventional Mode of Operation of Vibrational Gyroscopes

“…In the present paper, we present a complete search on single-axis vibration control using the ADRC can be time-varying rotation rates. Some preliminary results of our re unlike the previous approaches [3]- [10], capable of estimating to a solution that is intuitive to understand and easy to use, but, main challenges pertaining to vibrational gyroscopes. It leads large amount of uncertainties and time-varying parameters, the mental results in Section V. Finally, some concluding remarks are given in Section VI.…”

“…Most MEMS gyroscopes operate in a conven tional mode [3]- [8], where the movement of the mass along the drive axis is large and the movement along the sense axis is very small. Only a few studies [9], [10] addressed the vibra tions of the MEMS gyroscope operating in an adaptive mode, where the movements of a proof mass of the gyroscope along two vibrating axes are equal. In [4]- [7], oscillation controllers were introduced to force the gyroscope to resonance along drive axis.…”

“…In [8], a Lyapunov-based adaptive controller was designed to control the vibration on both drive and sense axes for the gy roscope, and to estimate a constant rotation rate. A majority of the reported controllers [3]- [10] assume constant rotation rates. In reality, the rotation rate is changing with time.…”

Minimal-Learning-Parameter Technique Based Adaptive Neural Sliding Mode Control of MEMS Gyroscope

“…In [11,12], the sliding mode control is proposed to handle the vibrating proof mass, which achieves better estimation of the unknown angular velocity than conventional model reference adaptive feedback controller. Since then, in the presence of significant uncertainties, the regulated model-based and non-modelbased sliding model control approaches are presented to improve tracking control of the drive and sense modes of the vibratory gyroscope in [13].…”

Sensing of the time-varying angular rate for MEMS Z-axis gyroscopes

“…Their approach compensates for model inaccuracies under the assumption that the angular rate is constant. In fact, most of the relevant past works considered the angular rate to be constant with respect to time [2,5,10,15,[19][20][21] where the angular rate, indeed, is a time-varying signal. Furthermore, on-line estimation of the time-varying angular rate is one of the major control problems associated with MEMS gyroscopes.…”