G.J.M. Krijnen's research while affiliated with University of Twente and other places

Publications (246)

Article
Full-text available
Microfluidic devices providing an accurate delivery of fluids at required rates are of considerable interest, especially for the biomedical field. The progress is limited by the lack of micropumps, which are compact, have high performance, and are compatible with standard microfabrication. This paper describes a micropump based on a new driving pri...
Preprint
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We investigate to what extent one can use a thermodynamic description of turbulent flow as a source of stochastic kinetic energy for three-dimensional self-assembly of magnetically interacting macroscopic particles. We confirm that the speed of the objects in the flow field generated in our system obeys the Maxwell--Boltzmann distribution, and thei...
Chapter
Full-text available
Crickets and other arthropods are evolved with numerous flow-sensitive hairs on their body. These sensory hairs have garnered interest among scientists resulting in the development of bio-inspired artificial hair-shaped flow sensors. Flow-sensitive hairs are arranged in dense arrays, both in natural and bio-inspired cases. Do the hair-sensors which...
Article
Full-text available
Current additive manufacturing allows for the implementation of electrically interrogated 3-D printed sensors. In this contribution various technologies, sensing principles and applications are discussed. We will give both an overview of some of the sensors presented in literature as well as some of our own recent work on 3-D printed sensors. The 3...
Article
A 2D sound particle velocity sensor, consisting of a cross of two connected, heated wires is presented. We developed a fabrication process by which the wires become freely suspended 350 mu m above the chip surface. This largely eliminates the influence of boundary layer effects and increases the temperature gradient along the wires, both due to the...
Article
In our work on micro-fabricated hair-sensors, inspired by the flow-sensitive sensors found on crickets, we have made great progress. Initially delivering mediocre performance compared to their natural counter parts they have evolved into capable sensors with thresholds roughly a factor of 30 larger than of their natural equivalents. Due to this dis...
Article
A two-dimensional acoustic particle velocity sensor as well as the required interfacing electronics have been designed and realized. The novel crossed-wire sensor structure provides a direct two-dimensional measurement and, contrary to current 2D particle velocity sensors, the sensitive directions are exactly orthogonal to each other due to the inh...
Article
In biology, hair-based sensor systems are used regularly for measurement of physical quantities like acceleration, flow, rotational rate, and IR light. In this chapter, two different types of bio-inspired sensors for inertial measurement are discussed, which have been developed using surface micromachining and SU-8 lithography. First, an accelerome...
Article
We report on a fully adaptable flow sensor with adjustable detection limit, responsivity, range, and bandwidth by addition of electrostatic spring hardening (ESH) to our previously developed microelectromechanical systems hair flow sensors. The sensor's mechanical transfer shows large voltage-controlled electromechanically affected responsivity for...
Article
A miniature force sensor for the measurement of forces and moments at a human fingertip is designed and realized. Thin silicon pillars inside the sensor provide in-plane guidance for shear force measurement and provide the spring constant in normal direction. A corrugated silicon ring around the force sensitive area provides the spring constant in...
Article
Full-text available
Despite vigorous growth in biomimetic design, the performance of man-made devices relative to their natural templates is still seldom quantified, a procedure which would however significantly increase the rigour of the biomimetic approach. We applied the ubiquitous engineering concept of a figure of merit (FoM) to MEMS flow sensors inspired by cric...
Article
Full-text available
Flies use so-called halteres to sense body rotation based on Coriolis forces for supporting equilibrium reflexes. Inspired by these halteres, a biomimetic gimbal-suspended gyroscope has been developed using microelectromechanical systems (MEMS) technology. Design rules for this type of gyroscope are derived, in which the haltere-inspired MEMS gyros...
Article
Stochastic resonance (SR) is a phenomenon that has been extensively investigated theoretically, but which is much harder to study experimentally. In this paper, we report on an experimental micromechanical slider structure that allows for full control of most of the parameters that are of importance for the occurrence of SR. Using a silicon-on-insu...
Article
Crickets use so-called clavate hairs to sense (gravitational) acceleration to obtain information on their orientation. Inspired by this clavate hair system, a one-axis biomimetic accelerometer has been developed and fabricated using surface micromachining and SU-8 lithography. An analytical model is presented for the design of the accelerometer, an...
Article
Hair sensors for oscillatory airflow, operating in the regime of bulk flow, particle velocity or both, can be characterized by several methods. In this work, we discuss harmonic measurements on MEMS hair flow sensors. To characterize this type of flow sensor the use of three different types of oscillatory airflow source is investigated. A loudspeak...
Article
Full-text available
We report on the application of parametric amplification to a micro Coriolis mass flow sensor. We demonstrate that this mechanism allows for reduction of the system's power dissipation while retaining sensitivity to flow. By reducing this power dissipation, less heat will be transferred to the fluid and channel, potentially resulting in reduced tem...
Chapter
MEMS offers exciting possibilities for the fabrication of bio-inspired mechanosensors. Over the last few years, we have been working on cricket-inspired hair-sensor arrays for spatio-temporal flow-field observations (i.e. flow camera) and source localisation. Whereas making flow-sensors as energy efficient as cricket hair-sensors appears to be a re...
Conference Paper
We report on an angular accelerometer based on the semicircular channels of the vestibular system. The accelerometer consists of a water-filled circular tube, wherein the fluid flow velocity is measured thermally as a representation for the external angular acceleration. Measurements show a linear response for angular acceleration amplitudes up to...
Conference Paper
A silicon capacitive force/torque sensor is designed and realized to be used for biomechanical applications and robotics. The sensor is able to measure the forces in three directions and two torques using four parallel capacitor plates and four comb-structures. Novel spring and lever structures are designed to separate the different force component...
Conference Paper
A silicon three-axis force sensor is designed and realized to be used for measurement of the interaction force between a human finger and the environment. To detect the force components, a capacitive read-out system using a novel relaxation oscillator has been developed with an output frequency proportional to differential capacitance. The sensor h...
Conference Paper
Crickets use so-called clavate hairs to sense (gravitational) acceleration to obtain information on their orientation. Inspired by this clavate hair system, a biomimetic accelerometer has been developed and fabricated using surface micromachining and SU-8 lithography. First measurements indicate that this MEMS hair-based accelerometer has a resonan...
Article
Biological sensory systems often display great performance, inspiring engineers to develop artificial counterparts. The lateral line system of fish has been widely studied by biologists for its crucial role in fish behaviour. Moreover recently the robustness, sensitivity and consequently wide range of applications that potentially benefit from the...
Conference Paper
A two-dimensional acoustic particle velocity sensor has been designed and realized. The novel crossed-wire sensor structure provides a direct two-dimensional measurement with sensitive directions exactly orthogonal to each other thus requiring no directivity calibration. This miniature design of size 1.0×2.5×0.5 mm dissipates only half the power re...
Conference Paper
We report on the application of parametric amplification to a micro Coriolis mass flow sensor to reduce the system's power dissipation while retaining sensitivity to flow. By reducing this power dissipation, less heat will be transferred to the fluid and channel, potentially resulting in more temperature-stable flow measurements. We show experiment...
Article
Full-text available
Crickets possess hairy organs attached to their abdomen, the so-called cerci. These cerci contain highly flow-sensitive mechanosensors that enable the crickets to monitor the flow-field around them and react to specific stimuli form the environment, e.g. air-movements generated by hunting spiders. Salient is the sensitivity of these sensors, which...
Conference Paper
A miniature capacitive force sensor for the measurement of shear- and normal force at the fingertip is designed and realized. The sensor has a circular design with a corrugated silicon ring around the force sensitive area. This ring provides the spring constant in shear direction and seals the interior of the sensor. Thin silicon pillars inside the...
Conference Paper
We demonstrate that, using stochastic resonance (SR) in a voltage-controlled MEMS-slider, the signal-to-noise ratio can be increased by adding white noise. Using a Silicon-on-Insulator (SOI) based process, we realised a slider structure with periodic capacitive structures to obtain tunable unstable regions. We implemented stochastic resonance by co...
Article
Full-text available
We present an electromechanical parametric scheme to improve the low-frequency signal-to-noise ratio of energy buffering type transducers. The method is based on periodic modulation of the stiffness in the sensory system which produces upconverted replicas of the signals of interest at frequencies where measurement is less troubled by noise or othe...
Article
In this paper, we present a two wire, two-dimensional particle velocity sensor. The miniature sensor of size 1.0 × 2.5 × 0.525 mm, consisting of only two crossed wires, shows excellent directional sensitivity in both directions, thus requiring no directivity calibration, and is relatively easy to fabricate. The sensor consists of two crossed beams...
Conference Paper
Full-text available
We present the controllable capillary folding of planar silicon nitride templates into 3D micro-structures by means of through-wafer liquid application. We demonstrate for the first time hydro-mechanical, repeatable, actuation of capillary folded structures via addition or retraction of water on demand.
Article
Full-text available
We present an overview of improvements in detection limit and responsivity of our biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors improves the responsivity by up to 80% for flow signals at frequencies below the sensor's resonance. Application of frequency matched AC-bia...
Article
Full-text available
Biologically inspired sensor-designs are investigated as a possible path to surpass the performance of more traditionally engineered designs. Inspired by crickets, artificial hair sensors have shown the ability to detect minute flow signals. This paper addresses developments in the design, fabrication, interfacing and characterization of biomimetic...
Article
We demonstrate that a micro Coriolis mass flow sensor can be excited in its torsional movement by applying parametric excitation. Using AC-bias voltages for periodic electrostatic spring softening, the flow-filled tube exhibits a steady vibration at suitable voltage settings. Measurements show that the sensor for this type of excitation can be used...
Conference Paper
We report on the design and fabrication of a MEMS-based gyroscopic system inspired by the fly's haltere system. Two types of so-called biomimetic gyroscopes have been designed, fabricated and their drive mode has been characterized. First measurements indicate excitable gyropscopes with natural frequencies in the order of 2 kHz and near critically...
Article
Full-text available
Flow-sensor arrays uncover the potential to measure spatio-temporal flow patterns rather than flow measurements at just a single point. We present in this paper the developments in design, fabrication and interfacing of biomimetic flow-sensor arrays, inspired by flow-sensitive organs (cerci) of crickets. For the purpose of high-resolution flow fiel...
Article
MEMS offers exciting possibilities for the fabrication of bioinspired mechanosensors. Over the last years we have been working on cricket inspired hair-sensor arrays for spatio-temporal flow-field observations (i.e flow-camera) and source localization. Whereas making flow-sensors as energy efficient as cricket hair-sensors appears to be a real chal...
Article
A simple optical method is proposed for performing in-plane experimental modal analysis of micromachined structures with a conventional charge-coupled device (CCD) camera. The motion of a micromechanical device actuated by high-frequency sinusoidal forces (kilohertz range) is recorded at the fixed sampling rate of a camera (typically, 28 frames/s)...
Article
We report improvements in the detection limit and responsivity of biomimetic hair-flow sensors by electrostatic spring softening. Applying a dc-bias voltage to our capacitive flow sensors results in a reduced sensory threshold, improving the mechanical transfer and flow detection limit by more than 6 dB. We further show that the sensor's responsivi...
Article
A micro-bimorph cantilever with self-aligned nanotips is monolithically integrated with a photonic crystal based device using optical and deep UV lithography techniques. Upon electrostatic actuation, the dielectric nanotips perturb the optical field, providing electromechano-optical modulation of light. Static tuning of the optical transmission spe...
Article
Full-text available
A systematic study is presented on the modelling, fabrication and measurements of curled micro-bimorph cantilevers, which are composed of a dielectric beam with a metal electrode layer coated on top. The device, having stress-induced upward curvature in the electrical off-state, functions as a vertical electrostatic actuator for nanometre displacem...
Article
We propose a new electromechanical interfacing scheme to improve the low-frequency response of energy buffering type transducers. The method is based on periodic modulation of the stiffness in the sensory system which allows to up-convert the signals of interest to frequencies where measurement is less troubled by noise or other detrimental effects...
Article
Full-text available
The Microflown, a novel acoustic flow sensor that is capable of measuring particle velocity in a fluid, can easily and accurately be calibrated in a standing-wave tube. This calibration method in the standing-wave tube is generally most favorable. Even very low frequencies can be measured with this simple setup. It is, therefore, important to analy...
Article
Full-text available
We demonstrate the versatility of a silicon nitride grated waveguide optical cavity as compact integrated optical sensors for (bulk) concentration detection, label-free protein sensing, and – with an integrated cantilever suspended above it – gas sensing.
Article
We demonstrate that the responsivity of flow sensors for harmonic flows can be improved significantly by non-resonant parametric amplification. Using electrostatic spring softening by AC-bias voltages, increased responsivity and sharp filtering are achieved in our biomimetic flow sensors. Tunable filtering is obtained for non-resonant electromechan...
Article
This paper presents the fabrication technology for a novel class of photonic devices which integrates silicon 2D photonic crystal (PhC) waveguides and electrostatically actuated microelectromechanical systems. Bimorph cantilevers equipped with tips that are self-aligned relative to the holes of the PhC modulate the propagation properties of the sla...
Conference Paper
We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC voltage to our capacitive flow sensors results in a reduced sensory threshold, which gives an improvement for the flow detection limit of more than 30%. In addition, the mechanical transfer shows large (8...
Article
Full-text available
The principle, fabrication and characterization of a dielectric MEMS cantilever located a few 100 nm above a racetrack ring resonator are presented. After fabrication of the resonators on silicon-on-insulator (SOI) wafers in a foundry process, the cantilevers were integrated by surface micromachining techniques. Off-state deflections of the cantile...
Article
We demonstrate a proof of concept of a novel and compact integrated mechano-optical sensor for H(2) detection based on a microcantilever suspended above a Si(3)N(4) grated waveguide. The fabricated devices are mechanically and optically modeled and characterized. Sensing operation of the sensor is demonstrated with 1% H(2) in N(2). The error in det...
Article
We demonstrate the versatility of a silicon nitride grated waveguide optical cavity as compact integrated optical sensors for (bulk) concentration detection, label-free protein sensing, and — with an integrated cantilever suspended above it — gas sensing.
Conference Paper
Full-text available
We present a straightforward method for measuring in-plane linear displacements of microelectromechanical systems (MEMS) with subnanometer resolution. The technique is based on Fourier transform analysis of a video recorded with a Charge-Coupled Device (CCD) camera attached to an optical microscope and can be used to characterize any device featuri...
Conference Paper
We report non-degenerate parametric amplification in our biomimetic MEMS hair-based flow-sensors with improved responsivity and sharp filtering through AC-biasing. To the best of our knowledge, this is the first flow sensor with tunable filtering by non-degenerate electromechanical parametric amplification, applicable at a wide range of non-resonan...
Conference Paper
A micro-bimorph cantilever is monolithically integrated with a photonic crystal micro-cavity based device, using surface micro-machining techniques. The integrated cantilever is equipped with self-aligned dielectric tips with respect to the holes of the photonic crystal and on electrostatic actuation, the tips move into the holes, providing electro...
Article
A technology to monolithically integrate micro-bimorph cantilevers equipped with tips that are self-aligned with respect to the holes of a 2D photonic crystal cavity-based channel-drop filter is presented. On electrostatic actuation, the tips move into the holes and provide electromechano-optical modulation of light. The technology allows the fabri...
Conference Paper
A proof-of-concept study is reported on fabrication and characterization of a novel and compact integrated mechano-optical sensor based-on a micro-bridge suspended above a Si<sub>3</sub>N<sub>4</sub> grated waveguide.
Conference Paper
We demonstrate, for the first time, the use of a monolithically integrated silicon nitride cantilever for tuning a silicon microring resonator over a 50 pm wavelength range by applying 8.5V, without affecting the ring's Q-factor.
Article
Full-text available
We demonstrate a monolithically integrated micromechano-optical device where the resonance wavelength of a silicon ring resonator is tuned by perturbing the evanescent field with an electrostatically actuated silicon nitride microcantilever. The resonance wavelength can be tuned over 125 pm.
Conference Paper
Full-text available
Next to image sensors, future's robots will definitely use a variety of sensing mechanisms for navigation and prevention of risks to human life, for example flow-sensor arrays for 3D hydrodynamic reconstruction of the near environment. This paper aims to quantify the possibilities of our artificial hair flow-sensor for high-resolution flow field vi...
Conference Paper
A photonic crystal slab waveguide (PhC-WG) with an integrated MEMS bimorph cantilever actuator has been successfully fabricated using deep UV lithography and surface micromaching techniques. The cantilever is equipped with tips that are self-aligned with respect to the holes of the PhC-WG such that on electrostatic actuation, with modest voltages o...
Article
Full-text available
We present the use of stochastic resonance in a MEMSslider for improvement of its sensing capability. Using a Silicon-on-Insulator (SOI) based process local instabilities can be realized by designing suitable geometries for capacitive structures. By controlling the strength of these capacitive wells by a DC voltage and adding a particular level of...
Article
Next to image sensors, future’s robots will definitely use a variety of sensing mechanisms for navigation and prevention of risks to human life, for example flow-sensor arrays for 3D hydrodynamic reconstruction of the near environment. This paper aims to quantify the possibilities of our artificial hair flow-sensor for high-resolution flow field vi...
Conference Paper
Full-text available
We present the design, modeling and characterization of a 3-phase electrostatic rotary stepper micromotor. The proposed motor is a monolithic device fabricated using silicon-on-insulator (SOI) technology. The rotor is suspended with a frictionless flexural pivot bearing and reaches an unprecedented rotational range of 30° (+/- 15°) at 65 V. We have...
Article
A dedicated microfabricated chip consisting of artificial hair sensors was realized and used to controllably and reliably investigate viscous coupling between the hair sensors. The experimental results confirm the presence of coupling effects between hair sensors when placed too close to each other. The results present significant insights in optim...
Article
Full-text available
In this paper we present the latest developments in the design, fabrication and application of single and arrays of biomimetic hair flow-sensors towards high-resolution air-flow imaging. Redesigning the electrode system of the hair sensor (using SOI wafer technology) has led to improve the detection limit down to 1 mm/s air-flow amplitude using 3 k...