This paper presents a low-voltage electrostatically actuated MEMS microgripper with high amplified displacements. The design incorporates a novel compliant mechanical amplifier that efficiently ...converts vertical motions into horizontal motions, resulting in a high amplification ratio of 9.25. The design incorporates a capacitive displacement sensor that can accurately measure the microgripper’s jaw movement. Finite Element Analysis (FEA) is utilized to optimize the design parameters, considering the fabrication constraints. The fabrication is based on the standard silicon-on-insulator micromachining process (SOIMUMPs), combined with an in-house etching process. Experimental testing demonstrates a maximum jaw displacement of 26.8 μm at a low applied voltage of 18 V. A successful grasping of a micro-object is demonstrated, which validates the practicality and effectiveness of the proposed design. Such a microgripper can be promising for the growing need for precise micromanipulation in various applications, such as biological cell manipulation and micro assembly.
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•A low-voltage electrostatically actuated MEMS microgripper with high amplified displacements is presented.•A compliant mechanical amplifier converts vertical motion to horizontal, achieving a high amplification ratio of 9.25.•A capacitive displacement sensor ensures precise micromanipulation and prevents excessive force during object handling.•Testing showed a 26.8 μm jaw displacement at 18 V, successfully grasping a micro-object, demonstrating its effectiveness.
This paper introduces a magnetic displacement sensor comprising of a double-layer parallel cables (PCs) magnetizer, tunnel magnetoresistance (TMR) sensors and magnetic flux concentrating plates ...(MFCPs). By utilizing a double-layer PCs magnetizer, the background magnetic field in the TMR sensor’s location can be eliminated, while enhancing the magnetization field of the workpiece. This ensures that the highly sensitive TMR sensors operates within its measurement range. Additionally, the MFCPs concentrate the magnetic field at the TMR sensor location to further improve the displacement measurement sensitivity. After optimizing the geometry and excitation frequency of the probe with FEM, the probe can achieve displacement measurements with 0.1 mm accuracy in the range of 0.5–6.0 mm for ferromagnetic workpieces with linearity of 4.5 % and average relative error under 2.0 %.
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•Parallel cables, magnetic displacement probe, ferromagnetic material, sensitivity enhancement, corrosion detection.•A magnetic displacement probe design replaces permanent magnets with lightweight energized parallel cables (PC).•This probe has minimal background noise and excellent sensitivity.•The probe offers a measuring range spanning 0.5 to 6.0mm, with a precise measuring accuracy of 0.1mm and a relative error of under 2.0%.•This probe holds promise for array displacement sensing and is well-suited for detecting deformation and corrosion in extensive ferromagnetic workpieces.
Monitoring structural displacement responses can provide quantitative information for both structural safety evaluations and maintenance purposes. To overcome the limitations of conventional ...displacement sensors, advanced noncontact vision-based systems offer a promising alternative. This study validates the potentials of the vision displacement sensor for cost-effective structural health monitoring. The results of laboratory experiments on simply-supported beam structures demonstrate the high accuracy of the vision sensor for dense full-field displacement measurements. The identified natural frequencies and mode shapes from measurements by using one camera match well with those from an array of accelerometers. Moreover, the smoother mode shapes make possible the noncontact damage detection based on the conventional mode shape curvature index. This study also discusses the issues concerning the practical applications of the vision displacement sensors, such as the scaling factor determination, measurement with small camera tilt angles, tradeoffs between the measurement resolution and measurement points or field of view, etc. Furthermore, the remote, real-time and multi-point measurement capacities of the vision sensor are confirmed through field tests of Manhattan Bridge during train passing.
•Full-field measurement accuracy has been demonstrated through laboratory experiments.•Damage detection is enabled from identified smoother mode shapes.•This study discusses the issues concerning practical applications of vision sensors.•Advantages of vision sensors are confirmed through field tests of Manhattan Bridge.
•Novel integrated Nano-Opto-Electro-Mechanical AFM sensor.•On-chip, waveguide-coupled, resonant cavity photodetector AFM readout.•Ultrasmall sensing element footprint 20 × 20 µm2.•Similar or better ...resolution compared to commercial AFM systems.
The low throughput of atomic force microscopy (AFM) is the main drawback in its large-scale deployment in industrial metrology. A promising solution would be based on the parallelization of the scanning probe system, allowing acquisition of the image by an array of probes operating simultaneously. A key step for reaching this goal relies on the miniaturization and integration of the sensing mechanism. Here, we demonstrate AFM imaging employing an on-chip displacement sensor, based on a photonic crystal cavity, combined with an integrated photodetector and coupled to an on-chip waveguide. This fully-integrated sensor allows high-sensitivity and high-resolution in a very small footprint and its readout is compatible with current commercial AFM systems.
Trifurcated optical fiber displacement sensors (OFDS) are increasingly used in industrial and aerospace applications. The critical element of the sensor is the fiber bundle. However, there is no ...straightforward method to calculate it from the working specifications of the sensor, the number of fibers needed, their size, and arrangement. This work presents a simple yet accurate method to design trifurcated OFDSs. The proposed method allows to derive the geometrical arrangement and size of the fibers from three simple equations, thus reducing significantly the difficulty and complexity of the OFDS design. Those three equations depend on the working point, working range, required sensitivity, and maximum size of the bundle. In this way, the proposed method will save valuable time for researchers and engineers who wish to design, fabricate, and use this type of OFDSs. The procedure is explained in detail with two examples. The results predicted by the model are compared with the experimental results of a bundle with identical fiber arrangement and dimensions. The results show good agreement with a deviation of less than 1% in the working range of the sensor.
Triboelectric nanogenerator-based vibration sensors (TVSs) present a promising approach for online vibration monitoring, offering early detection of excessive vibrations that pose risks to the ...functionality of devices and infrastructure. However, the structural design of most current TVSs lacks consideration for information processing capabilities, resulting in limited detection bandwidth and displacement signal fidelity. This study first introduces a quasi-zero-stiffness (QZS) mechanical-computing metastructure aimed at enhancing the structural intelligence of TVSs and extending their vibration signal detection bandwidth. The optimization of the QZS metastructure involved adjusting the length ratio and inclination angle of the zero-order polynomial beam to achieve ultra-low resonant frequencies. The results indicate that the TVS based on the mechanical-computing metastructure (MCM-TVS) is capable of efficiently detecting complex random signals, achieving an average measurement accuracy above 85 % for the spectral components of random vibration signals. Furthermore, the sensor exhibited remarkable linearity (99 %) in measuring vibration amplitude and maintained consistent sensitivity (with less than 25.8 % fluctuation), facilitating the lossless conversion of displacement to electrical signals. Consequently, this novel approach of incorporating an MCM into TVS design offers substantial insights for the advancement of high-performance vibration signal monitoring.
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•A novel vibration sensor based on triboelectric nanogenerators (TVS) is proposed.•The mechanical-computing metastructure (MCM) is first introduced to design TVSs.•MCM-TVS improves the detection bandwidth and signal fidelity of current TVSs.•MCM-TVS has superior structural intelligence and effectively monitors random signals.•MCM's computational capability is enabled by the quasi-zero-stiffness property.
We report a single-electrode-based sliding-mode triboelectric nanogenerator (TENG) that not only can harvest mechanical energy but also is a self-powered displacement vector sensor system for ...touching pad technology. By utilizing the relative sliding between an electrodeless polytetrafluoroethylene (PTFE) patch with surface-etched nanoparticles and an Al electrode that is grounded, the fabricated TENG can produce an open-circuit voltage up to 1100 V, a short-circuit current density of 6 mA/m2, and a maximum power density of 350 mW/m2 on a load of 100 MΩ, which can be used to instantaneously drive 100 green-light-emitting diodes (LEDs). The working mechanism of the TENG is based on the charge transfer between the Al electrode and the ground by modulating the relative sliding distance between the tribo-charged PTFE patch and the Al plate. Grating of linear rows on the Al electrode enables the detection of the sliding speed of the PTFE patch along one direction. Moreover, we demonstrated that 16 Al electrode channels arranged along four directions were used to monitor the displacement (the direction and the location) of the PTFE patch at the center, where the output voltage signals in the 16 channels were recorded in real-time to form a mapping figure. The advantage of this design is that it only requires the bottom Al electrode to be grounded and the top PTFE patch needs no electrical contact, which is beneficial for energy harvesting in automobile rotation mode and touch pad applications.
This paper proposes a novel Fiber Bragg Grating (FBG)-based hybrid force and displacement sensor with a high sensitivity to achieve accurate measurement of radial artery pulse waveforms. The proposed ...sensor prototype mainly consists of a force-sensitive orthogonal planar spring structure, an FBG optical fiber, and a sensor frame. The side-type orthogonal planar spring flexure has been utilized and optimized to achieve an excellent linear force-displacement relationship along the axial direction. It offers other merits in terms of equivalent functions as a parallel mechanism configuration, compactness, and convenient assembly. The employed optical fiber has been tightly stretched to form a suspended configuration vertical to the flexure's central line. This two-point pasting configuration and the use of the transverse movement property of the suspended fiber can achieve improved sensitivity and resolution, and avoid shortcomings associated with the traditional and direct pasting for the whole FBG element. The theoretical model that corresponds to the sensing principle has been derived. The simulation based on finite element method (FEM) has been adopted to conduct design optimization to determine detailed structural parameters and achieve enhanced sensitivity, as well as performance investigation. The optimized prototype has demonstrated an excellent force resolution of 0.47mN with a small linearity error of 0.98% within the sensing range 0.9N, 2.7N and a high displacement sensitivity of <inline-formula> <tex-math notation="LaTeX">0.103\mu \text{m} </tex-math></inline-formula> with a linearity error of 4.08% within the sensing range 0.3mm, 0.7mm, and the R 2 values are determined as 99.99% and 99.30%, respectively. The experiments for artery pulse waveform measurement have been performed to validate the effectiveness of the proposed sensor design.
•A 1D displacement sensor based on a microstrip line loaded with broadside-coupled split-ring resonators is presented.•A modified resonator geometry extends the concept to realize a 2D displacement ...sensor with high dynamic range.•The principle of operation of the sensors is based on a shift in resonance frequency caused by a break of symmetry.•The mode of operation makes the sensor highly immune to environmental noise and changes in temperature.•The proposed sensors detects break of symmetry and thus can be used as alignment sensors as well.
This paper proposes a two-dimensional alignment and displacement sensor based on movable broadside-coupled split ring resonators (BC-SRRs). As a basis for this sensor, a one-dimensional displacement sensor based on a microstrip line loaded with BC-SRRs is presented firstly. It is shown that compared to previously published displacement sensors, based on SRR-loaded coplanar waveguides, the proposed one-dimensional sensor benefits from a much wider dynamic range. Secondly, it is shown that with modifications in the geometry of the BC-SRRs, the proposed one-dimensional sensor can be modified and extended by adding a second element to create a high-dynamic range two-dimensional displacement sensor. Since the proposed sensors operate based on a split in the resonance frequency, rather than the resonance depth, they benefit from a high immunity to environmental noise. Furthermore, since the sensors’ principle of operation is based on the deviation from symmetry, they are more robust to ambient conditions such as changes in the temperature, and thus they can be used as alignment sensors as well. A prototype of the proposed two-dimensional sensor is fabricated and the concept and simulation results are validated through experiment.
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