Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

Mol, L.; Rocha, Licinio; Cretu, Edmond; Wolffenbuttel, R.F.

doi:10.1088/0960-1317/19/7/074020

Cited by 6 publications

(5 citation statements)

References 8 publications

(8 reference statements)

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“…The MEMS-SM controller contains a low-pass filter (i.e. 6th order Bessel filter with a programmable cutoff frequency) for each axis drive input to reduce the mirror's mechanical oscillations that result from a step input signal [9]. In order to characterize the MEMS-SM switching speed, the time-domain step-response was measured for different low-pass cutoff frequencies ranging from 40 Hz to 200 Hz.…”

Section: Lidar Configuration Based On a Mems Scanning Mirrormentioning

confidence: 99%

Eye-safe diode laser Doppler lidar with a MEMS beam-scanner

Hu¹,

Pedersen²,

Rodrigo³

2016

Opt. Express

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We present a novel Doppler lidar that employs a cw diode laser operating at 1.5 μm and a micro-electro-mechanical-system scanning mirror (MEMS-SM). In this work, two functionalities of the lidar system are demonstrated. Firstly, we describe the capability to effectively steer the lidar probe beam to multiple optical transceivers along separate lines-ofsight. The beam steering functionality is demonstrated using four lines-ofsight -each at an angle of 18° with respect to their symmetry axis. Secondly, we demonstrate the ability to spatially dither the beam focus to reduce the mean irradiance at the probing distance (R = 60 m) of each lineof-sight -relevant for meeting eye-safety requirements. The switching time of the MEMS-SM is measured to be in the order of a few milliseconds. Time-shared (0.25 s per line-of-sight) radial wind speed measurements at 50 Hz data rate are experimentally demonstrated. Spatial dithering of the beam focus is also implemented using a spiral scan trajectory resulting in a 16 dB reduction of beam focus mean irradiance.

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Section: Lidar Configuration Based On a Mems Scanning Mirrormentioning

confidence: 99%

Eye-safe diode laser Doppler lidar with a MEMS beam-scanner

Hu¹,

Pedersen²,

Rodrigo³

2016

Opt. Express

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“…One reason accounting for the faster rising edge response is the air damping [19]. As the cantilever oscillates, the nontrivial air film between the V shape groove and the cantilever is squeezed and sheared causing a built-up force against the motion of the cantilever.…”

Section: Dynamic Responsementioning

confidence: 99%

“…However, the damping, caused by dynamically loading of the cantilever, leads to the cantilever to settle quicker. It suggests that input shaping method [19] can be adopted to tune the settling time and the positioning speed for a desirable response; it also indicates that the working configuration of the actuator under tension is favorable.…”

Section: Dynamic Responsementioning

confidence: 99%

Monolithic transparent 3D dielectrophoretic micro-actuator fabricated by femtosecond laser

Yang¹,

Bellouard²

2015

J. Micromech. Microeng.

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We demonstrate a three-dimensional (3D) monolithic micro-actuator fabricated by nonablative femtosecond laser micromachining and subsequent chemical etching. The actuating principle is based on dielectrophoresis. An analytical modeling of this actuation scheme is conducted, which is capable of performance prediction, parameter optimization and instability analysis. Static and dynamic characterizations are experimentally verified. An actuation range of 30 μm is well attainable; resonances are captured with an evaluated quality factor of 40 (measured in air) and a bandwidth of 5 Hz for the primary vertical resonance of 200 Hz. A settling time of 200 ms in transient response indicates the damping properties of such actuation scheme. This actuation principle suppresses the need for electrodes on the mobile, nonconductive component and is particularly interesting for moving transparent elements. Thanks to the flexibility of the manufacturing process, it can be coupled to other functionalities within monolithic transparent micro-electro-mechanical systems (MEMS) for applications like tunable optical couplers.

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“…micromirrors) are generally operated in the pre-pull-in regime, wherein the equilibrium states are successively changed over the desired time intervals, which inherently leads to motion induced oscillations. In the past, commandshaping has been shown to be an effective tool to nullify such motion induced oscillations, nevertheless, nonlinearity associated with the electrostatic actuation and the energy dissipation mechanisms operating at the microscale pose significant challenges in arriving at the optimum waveform [29]. In this connection, energy-based approaches have been described in the literature to control the dynamics of nonlinear systems [30].…”

Section: Journal Of Micromechanics and Microengineeringmentioning

confidence: 99%

Mitigation of residual oscillations in electrostatically actuated microbeams using a command-shaping approach

Godara

Joglekar

2015

J. Micromech. Microeng.

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When electrostatically actuated microbeams are driven by an input-waveform comprising multiple voltage steps, the resulting response inherently contains residual oscillations, which may prove detrimental to the device performance and accuracy. In this article, we report the systematic development of a command shaping technique for mitigating such residual oscillations in electrostatically actuated microbeams and achieving fast switching between the successive equilibrium states. Invoking the force balance at a critical point in an oscillation cycle, the proposed technique relies on bringing the actuator to a stagnation state by applying an additional voltage signal of specific amplitude at a predetermined time. The underlying principle of the technique is enunciated for the lumped parallel-plates model of the microactuator, and further extended to the cases of microbeams. The electromechanical model of the microbeam incorporates the effects of full-order electrostatic nonlinearity, moderately large deflections, viscous energy dissipation, and fringing fields. The modal superposition method is employed to obtain the dynamic response of microbeams. Based on a single-mode assumption, the proposed technique lends itself to a simple multistep waveform, which is attractive from the implementation point of view. The applicability of the proposed technique is demonstrated by considering a wide range of parameters involving variations in the extent of geometric nonlinearity, damping, and equilibrium sequences. The impact of higher modes on the stabilized response is exposited, and a command shaping approach based on the multi-mode response of the actuator is suggested. In particular, such an approach is shown to be effective in controlling the motion of the beam in the vicinity of the static pull-in displacement, which is associated with strong electrostatic nonlinearity. The present investigation can find its potential use in the development of an open-loop controller for electrostatically actuated microbeams.

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Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

Cited by 6 publications

References 8 publications

Eye-safe diode laser Doppler lidar with a MEMS beam-scanner

Eye-safe diode laser Doppler lidar with a MEMS beam-scanner

Monolithic transparent 3D dielectrophoretic micro-actuator fabricated by femtosecond laser

Mitigation of residual oscillations in electrostatically actuated microbeams using a command-shaping approach

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