Signal Measurement and Estimation Techniques for Micro and Nanotechnology

Within these last decades, we assist the spectacular emergence of the micro and nanotechnology. These technologies are tools derived from several complementary fields like micro/nanorobotics, control, biology, mechanics, physics and chemistry. Considered scale is between some tens of nanometers to some hundreds of micrometers. At this scale, manipulating objects, measuring signals or controlling systems constitute a great challenge because of the non-classical specificities that exist. In particular, since several years, researchers and engineers attempt to develop convenient measurement techniques or sensors (technology) for the micro/nano-scale. The spirit was that these techniques or technology could provide essential information and signals during the positioning, manipulation or assembly (position and force signals) of micro/nano-objects or on their characteristics (stiffness, etc.) with the required resolution, accuracy, range and bandwidth. These last years, additionally to the performances, several projects also highlight the packageability aspects. This chapter reminds the specificities of the micro/nanoworld. After introducing the chapter, dimensions, ranges and order of magnitudes that typify this world will be given. Thanks to the literature survey, it will be demonstrated that the signals measurement at the microworld is a new and open field due to the lack of sensors presenting at the same time the embeddability, the required precision and large range, and low cost. Finally, we present the possible contribution of observer and estimator theory to the measurement at the micro/nano-world in order to complete the measurement provided by existing sensors.

This chapter aims to develop a self-sensing technique to measure the displacement and the force in piezoelectric microactuators dedicated to micromanipulation and microassembly contexts. In order to answer the requirements in these contexts, the developed self-sensing should perform a long duration measurement of constant signals (displacement and force) as well as a high precision. Furthermore, we propose to consider the dynamics in the displacement self-sensing measurement such that a positioning feedback is possible and therefore a high micro/nanopositioning accuracy is obtained. The experimental results validate the proposed technique and demonstrate its conveniency for micromanipulation and microassembly contexts.

Dexterous manipulation of small components and assembly of microsystems require measurement and control of gripping forces. In the microworld,1 the main limitation for force sensing is the low signal to noise ratio making very difficult to achieve efficient force measurements when useful signals magnitudes are close to noise level. Thus, optimal filters allowing both filtering the noise without loss of dynamic measurements and an easy real time implementation for force control are required. This chapter deals with gripping force measurement and control in the microworld describing successful uses of the optimal Kalman filtering to overcome the limitations due to noise. Two applications are then presented: the first one focuses on the improvement of strain gauges micro-forces measurement using an optimal Kalman filter, and the second one describes a successful implementation of a LQG (Linear–quadratic–Gaussian) gripping force controller on an electrostatic microgripper for the dexterous manipulation of 80 μm glass balls.

The increasing interest in investigating ever smaller samples and the industrial trend toward miniaturization has created a need for new metrological tools and methodologies for micromechanical measurements. Within this chapter, MEMS-based single-axis as well as multi-axis capacitive microforce-sensing tools enabling the measurement of forces in the micronewton to nanonewton range are presented. By combining sensing as well as actuation elements on a single chip, a monolithically integrated multi-axis microtensile-tester chip is shown, allowing the direct measurement of the mechanical as well as electrical properties of a microscale sample along multiple directions. The design, microfabrication, and characterization are discussed. Motivated by the unavailability of reference standards in the nanonewton range, a methodology for the calibration of microforce sensors is developed. In combination with the implementation of the latest advancement in the field of multivariate uncertainty analysis using a Monte Carlo method, this allows for SI-traceable microforce measurements in the nanonewton to micronewton range. At the end of this chapter, the application of the microtensile tester chip is demonstrated for the quantitative micromechanical investigation of individual plant cells in their living state.

Assisted reproduction technologies (ART) require the reproductive quality of oocytes to be efficiently assessed. This chapter presents a cellular force measurement technique that allows for mechanical characterization of mouse oocytes during microinjection (i.e., in situ) without requiring a separate characterization process. The technique employs an elastic cell holding device and a sub-pixel computer vision tracking algorithm to resolve cellular forces in real time with a nanonewton force measurement resolution (2 nN at 30 Hz). The experimental results demonstrate that the in situ obtained force-deformation data are useful for distinguishing healthy mouse oocytes from those with aging-induced cellular defects. Biomembrane and cytoskeleton structures of the healthy and defective oocytes are also investigated to correlate the measured subtle mechanical difference to the cellular structure changes. The technique represents a promising means to provide a useful cue for oocyte quality assessment during microinjection.

Thin-film nanostructures from various materials have a great potential to further miniaturize the devices like nanoelectronics and micromachines. Recently semiconductor nanofilms, mono or multiple atomic layer carbon nanofilms have been synthesized. However, the precise electrical and mechanical properties of these structures still need to be characterized in more detail. In this chapter, we introduce a large range force sensing tool that we recently developed. Three-dimensional piezorsistive helical nanobelts (HNB) will be described including their giant piezoresistivity. Their large force sensing range is characterized and calibrated by incorporating in situ scanning electron microscope (SEM) tuning fork sensors. This in situ characterization clearly revealed the non-constant stiffnesses of HNBs. Finally, as an application example, mechanical properties of nanowires are characterized by the HNBs. The proposed large range force characterization system is useful and promising toward creating thin-film micro and nanodevices.

Optical-based force sensors can provide the desired resolution and maintain relatively large sensing ranges for cell manipulation and microneedle injections via a force-sensing method that uncouples the conflicting design parameters such as sensitivity and linearity. Presented here is a mechanism approach for enhancing the performance of a surface micromachined optical force sensor. A new design is presented, which introduces a special mechanism, known as the Robert’s mechanism, as an alternate means in which the device is structurally supported. The new design’s implementation is achievable using an equivalent compliant mechanism. Both analytical pseudo-rigid-body modeling and FEA methods are used for determining the geometric parameters of the compliant Robert’s mechanism, optimized to obtain a sensor with improved linearity and sensitivity. Overall, the force sensor provides higher sensitivity, larger dynamic range, and higher linearity compared to a similar optical force sensor that uses a simple structural supporting scheme. In summary, the effectiveness of using a mechanism approach for enhancing the performance of MEMS sensors is demonstrated.

This chapter discusses a possible state-observer approach for various estimation problems arising in the context of so-called Scanning Probe Microscopes. The discussion is based on the example of the Electric Force Microscope. It is first emphasized how a typical force measurement purpose can be formulated as a model-based state observer problem, for which some standard Kalman observer can for instance be designed. The notion of parametric amplification sometimes used in order to enhance force measurement accuracy is then interpreted in the light of the here discussed observer approach. Finally, the issue of parameter estimation for this model-based approach is also discussed. All of those items are illustrated with the considered example and corresponding simulation results.