Initialization of the BIMBO self-test method using binary inputs and outputs

International audienceThis paper deals with the initialization of the BIMBO method, a deterministic identification method based on binary observation, for the (self-) test of integrated electronic and electromechanical systems, such as MEMS. Finding an adequate starting point for the parameter estimation algorithm may be crucial, depending on the chosen model parameterization. We show how this starting point may be obtained using only binary inputs and outputs and a few straightforward calculations. The practical implementation of this method only requires a one-bit digital-to-analog converter (DAC) and a one-bit analog-to-digital converter (ADC). This makes the proposed approach very amenable to integration and leads to no additional cost compared to the BIMBO method. We describe the method from a theoretical point of view, discuss its implementation and illustrate it in some idealized cases

Identification of a one-bit lowpass sigma-delta modulator using BIMBO

International audienceWe show how the BIMBO identification method can be used for the online identification of the digital filter in a sigma-delta modulator's loop. This parameter estimation method only requires the knowledge of the bit stream at the modulator output. This approach does not rely on an approximation of the comparator (such as additive white noise or describing function approximation). Moreover, it requires no amplitude measurement, as opposed to most other methods, and, thus, it involves no additional electronics and it is therefore very economical to implement it practically. The method is described from a theoretical point of view and an experimental validation is given

Modelling of nonlinear circular plates using modal analysis: simulation and model validation

A method for simulating the large-displacement actuation of deformable micro-structures is proposed and illustrated in the case of a circular axisymmetric plate. First of all the problem is formulated and its boundary conditions are expressed as functions of the two unknowns, displacements and the Airy stress function. The problem is then split into two parts, each part corresponding to one equation of Von Karman, to which the techniques of modal analysis are applied in order to obtain a set of nonlinear ordinary differential equations. The implementation of the resulting high-level model is then discussed and some simulation results are given, as a basis for comparison

Control Law Design for Distributed Multi-Agent Systems

In this paper, the problem of control law design for decentralized homogenous Multi-Agent systems ensuring the global stability and global performance properties is considered. Inspired by the decentralized control law design methodology using the dissipativity input-output approach, the problem is reduced to the problem of satisfying two conditions: (i) the condition on the interconnection and (ii) the condition on the local agent dynamics. Both problems are e fficiently solved applying a (quasi-) convex optimization under Linear Matrix Inequality (LMI) constraints and an H infinity synthesis. The proposed design methodology is applied to the control law design of a synchronous PLLs network

H∞ Loop shaping control for PLL-based mechanical resonance tracking in NEMS resonant mass sensors

International audienceAbstract--A simple dynamic detection of the resonance frequency shift in NEMS resonant mass sensors is described. This is done without the use of an external frequency sweep signal nor a frequency counter limiting the dynamic variation detection. Neither an amplitude control nor a phase switcher is required for maintaining the resonant oscillations. The sensor is driven directly by the VCO's output for which the control signal is calculated by a robust H∞ controller using loopshaping method. Only the sensor and the VCO's signals signs are detected and compared so that the controller regulates the phase difference between them, maintaining it at π / 2 which occurs on resonance frequency. The measurement issue is transformed to a novel control problem that rejects the disturbance described by the resonance frequency shift, attenuates the phase noise and guarantees good stability margins

A robust control method for electrostatic microbeam dynamic shaping with capacitive detection

International audienceA robust closed-loop control and observation methodology for an electrostatic dynamic shaping of a microbeam using N small separate electrodes is described. After decomposing the displacements vector on the n eigenmodes using the modal analysis, n controllers are designed to control the dynamic coefficients of each mode and thus to deliver the stresses that must be distributed throughout the beam. In previous works, we considered direct access to non noisy displacement measurements. In this paper, we investigate the capacitive measurement of the local displacements done by each small electrode, which gives a noisy readout. Robust control methodology applied on extended standard model permits to design n observers associated to n controllers and guarantees precise shape tracking, free from noise and robust against parameters incertitud

Estimation quality of a weighted least-square parameter estimation method based on binay observations

International audienceIn this paper, we investigate the quality of a weighted leastsquare (WLS) parameter estimation method based on binary observations when only a finite number of samples are available. An upper bound of the number of samples that are necessary for identifying system with a given accuracy is theoretically derived. The accuracy is defined in the sense of correlation coefficient between the system parameters and our estimated system parameters. Furthermore, we compare theoretical results with simulations in order to study the validity of the results practically

Microbeam dynamic shaping by closed-loop electrostatic actuation using modal control

International audienceA closed-loop control approach for the dynamic shaping of a microbeam by electrostatic actuation is described. Starting from a desired displacements reference vector of N small segments of the beam (representing the approximation of the continuous case), n controllers (n is the number of considered modes) output the stresses that must be distributed throughout the beam, on the N actuators. Because this reference may vary with time, the controllers are designed so that they accomplish good response dynamics, as well as performance and robustness specifications. The innovation in this method is that we control the dynamic coefficients associated to the modes of the microbeam and not directly the physical displacements in each small segment, which reduces the number of correctors from N to the number of n modes to control

A Recursive System Identification Method Based on Binary Measurements

An online approach to parameter estimation problems based on binary observations is presented in this paper. This recursive identification method relies on a least-mean squares approach which makes it possible to estimate the coefficients of a finite-impulse response system knowing only the system input and the sign of the system output. The impulse response is identified up to a positive multiplicative constant. The role of the regulative coefficient is investigated thanks to simulated data. The proposed method is compared with another online approach: it is shown that the proposed method is competitive with the other one in terms of estimation quality and of calculation complexity