Parallel Finger Research Articles

All-in-one microfluidic device with an integrated porous filtration membrane for on-site detection of multiple salivary biomarkers

A hand-held microfluidic device is developed with an integrated filtration membrane for electrochemical monitoring of multiple salivary biomarkers. The platform consists of array of screen-printed electrodes, integrated with a high throughput microfluidic system that was developed via clean-room free 3D-printing technique. A ‘channel-inside-channel’ configuration is introduced to facilitate pump-less passive flow of saliva at the broad sensing chambers. In order to eliminate the salivary protein based biofouling problems, a flexible porous filtration membrane is integrated at the microfluidic inlet that avoids the passage of bulkier protein constituents. As the presence of separate insulator layer on the sensing electrodes adversely affects its integration with the fluidic channel, the electrode substrate itself is utilized as the insulator by exposing the bottom region of the printed electrodes as active region. Enzyme based electrochemical sensors are developed with suitable nanomaterials for monitoring glucose, lactate, cholesterol and uric acid from collected saliva samples. The device showed distinct differences in salivary glucose levels for healthy subjects before and after consuming glucose-rich drinks. The glucose sensor responses are validated with high performance liquid chromatography and commercial colorimetric assay methods, and observed good correlation with parallel finger prick blood glucose measurements with an average Pearson coefficient of 0.9161, demonstrating its efficacy in saliva based point-of-care analysis.

Design and Research of Multifunctional Dexterous Hands Based on Parallel Finger Structure

Design and Research of Multifunctional Dexterous Hands Based on Parallel Finger Structure

Design of dexterous hands based on parallel finger structures

The dexterous hands with high dexterity, high carrying capability, high precision and high task adaptability (multipurpose) are demanded in industry. This paper focuses on designing dexterous hands based on the parallel finger structures to improve above performances. Based on the motion property of human finger, the required motion types of the dexterous hands are proposed. The finger structures of RR-RPR and 2-UU-UPU are presented by structural evolution from the well-known PMs of parallelogram and 3-UU by means of group deduction, respectively. Two three-finger dexterous hands are designed by assembling the obtained parallel fingers on the palm in the same direction. The in-hand configurations are actually hybrid mechanisms, whose motion properties are analyzed by equivalent to the parallel mechanisms (PMs). The hands have high task adaptability that can perform the pinching operations both from the outside and inside the cavity of the objects. The kinematics of the fingers are presented to investigate the workspace performance, and the statics are analyzed to prove that the proposed parallel dexterous hands can provide desirable pinching force.

Synthesis of 3-[P][S] Parallel Mechanism-Inspired Multimode Dexterous Hands With Parallel Finger Structure

Abstract Dexterous hands are an important end-effector of robots, but their relatively low carrying capacity, small workspace and poor task adaptability are the key factors that restrict their wide application. To overcome these shortcomings of dexterous hands, a novel Lie-group-based synthesis method that extends the 3-[P][S] parallel mechanisms (PMs) to dexterous hands is presented, and a class of three-finger dexterous hands with parallel finger structure is obtained. The multimode operation is proposed by designing a double-slider palm that provides the hands with a large workspace and high task adaptability. The operation types are presented, and the dexterous in-hand manipulations in all modes are analyzed by means of Lie group theory. In addition, the equivalent structural characteristics of pinching objects are classified to elucidate the motion types and the rotational properties of the pinched objects. The inverse kinematics of fingers is presented and is used to identify the input–output relationships. Finally, the workspaces of the fingers are determined according to the result of the inverse kinematics, and the relationships between the size and displacements of the pinched object are presented. The proposed dexterous hands overcome the problems of low carrying capability, small workspace, and weak in-hand manipulation ability that are encountered with the traditional dexterous hands, which are underactuated and are built with a series finger structure, and can be potentially applied to various application domains, such as services, industry, and rescue.

Application of 3D printed polymer composite as capacitive sensor

PurposeThe purpose of this study is to demonstrate the usage of three-dimensionally (3D) printed polylactic acid (PLA)-carbon black (CB) conductive polymer composite in the measurement of the void fraction and liquid level.Design/methodology/approachPLA-CB conductive polymer composite is 3D printed through fused deposition modelling (FDM) technique and used as a capacitive sensor for void fraction measurement and liquid level sensing. The sensitivity of 3D printed ring and concave type capacitive sensors are compared for void fraction measurement. The effect of electrode length, thickness and pipe dimension on the capacitance achievable for the particular void fraction is studied. Concept of fringing capacitance is used for the sensing of liquid level.FindingsCompared to the concave design comprising four electrodes, the ring-type capacitive sensor produced better results in void fraction measurement. Increase in pipe diameter and electrode length results in the enhancement of capacitance arising from specific void fraction. For a 100 mm diameter pipe, the capacitance of the 150 mm-long concave electrode (0.4 mm thick) increased from 9.98 to 67.77 pF as the void fraction decreased from 100% to 0%. Development of the fringing capacitance in 3D printed PLA-CB composite helps in the measurement of liquid level. Both parallel finger topology and interdigital electrode configuration are able to sense the liquid level.Originality/valueAbility of the 3D printed conductive PLA-CB composite to act as a capacitive sensor is experimentally analysed. Performance of different electrode configuration is tested for both void fraction measurement and liquid level sensing. Results of experimentation prove that FDM printed PLA-CB composite is suitable for the void fraction and liquid level measurement.

Pick-and-Place Task Implementation Using Visual Open-Loop Control

Abstract In the ever increasing number of robotic system applications in the industry, the robust and fast visual recognition and pose estimation of workpieces are of utmost importance. One of the ubiquitous tasks in industrial settings is the pick-and-place task where the object recognition is often important. In this paper, we present a new implementation of a work-piece sorting system using a template matching method for recognizing and estimating the position of planar workpieces with sparse visual features. The proposed framework is able to distinguish between the types of objects presented by the user and control a serial manipulator equipped with parallel finger gripper to grasp and sort them automatically. The system is furthermore enhanced with a feature that optimizes the visual processing time by automatically adjusting the template scales. We test the proposed system in a real-world setup equipped with a UR5 manipulator and provide experimental results documenting the performance of our approach.

Task and Context Sensitive Gripper Design Learning Using Dynamic Grasp Simulation

In this work, we present a generic approach to optimize the design of a parametrized robot gripper including both selected gripper mechanism parameters, and parameters of the finger geometry. We suggest six gripper quality indices that indicate different aspects of the performance of a gripper given a CAD model of an object and a task description. These quality indices are then used to learn task-specific finger designs based on dynamic simulation. We demonstrate our gripper optimization on a parallel finger type gripper described by twelve parameters. We furthermore present a parametrization of the grasping task and context, which is essential as an input to the computation of gripper performance. We exemplify important aspects of the indices by looking at their performance on subsets of the parameter space by discussing the decoupling of parameters and show optimization results for two use cases for different task contexts. We provide a qualitative evaluation of the obtained results based on existing design guidelines and our engineering experience. In addition, we show that with our method we achieve superior alignment properties compared to a naive approach with a cutout based on the “inverse of an object”. Furthermore, we provide an experimental evaluation of our proposed method by verifying the simulated grasp outcomes through a real-world experiment.

Micro-USB Connector Pins as Low-Cost, Robust Electrodes for Microscale Water Conductivity Sensing in Oceanographic Research

Motivated by the widespread need to sense water conductivity in oceanography, as well as in other applications in fluid dynamics and environmental monitoring, we propose using the exposed gold-plated pins of readily available micro-USB connectors as miniaturized, parallel finger electrodes. Since the electrodes are 600 μm apart, they grant sub-mm spatial resolution, suitable for most applications. Standard micro-USB cables are an ideal, ready-to-use solution, since they are shielded, are preassembled in different lengths, and enable 2 and 4-wire measurements. In order to take full advantage of these USB probes, we have designed a custom, open-source 4-channel measuring circuit, named “Conduino”, consisting of a low-noise (SNR = 60 dB) shield board coupled to an Arduino microcontroller. Experimental results demonstrate sensing performances comparable with state-of-the-art reference instrumentation (0.1% resolution in the 0.1-15 S/m range), with significantly lower cost and increased versatility and reliability.

Artifizielle Synostose zur Rekonstruktion bei traumatischem Metakarpaledefekt: Fallbericht

Reconstruction of traumatic metacarpal defects is still challenging because of the key function of the architecture of the metacarpus for the function of the entire hand. Especially the exact restoration of the rotation for a parallel finger movement plays an important role. There are less information on this topic in the literature. We present a 28-year old patient with a traumatic almost complete defect of the fourth metacarpal. Reconstruction of the metacarpal arch was achieved with an artificial synostosis between the intact head of the 4th metacarpal and the 3rd metacarpal.

The role of the basal ganglia in bimanual coordination

The functional anatomical role of the basal ganglia in bimanual coordination is unknown. Utilizing functional MRI (fMRI) at 3 T, we analyzed brain activity during three different typing tasks. The first task consisted of typing with parallel finger movements (moving left to right with four fingers on both hands). The second task was mirror movements (moving little finger to index finger on both hands), and the third task compared a resting condition with right-handed unimanual typing (moving little finger to index finger). Task dependent BOLD activity in the supplementary motor area (SMA) and dorsolateral premotor areas was observed. In addition, activation patterns were present in the cerebellar vermis during bimanual coordination tasks, with greater activation in the parallel than in the mirror condition. Finally, we also identified activity in the putamen during the tasks described above. Interestingly, putaminal activity was greatest during the period of motor task initiation, and activity during this period was greatest in the parallel condition. Our results suggest a critical role of the basal ganglia in the neural control of bimanual coordination.

Suppression of the non-dominant motor cortex during bimanual symmetric finger movement: A functional magnetic resonance imaging study

Patterns of bimanual coordination in which homologous muscles are simultaneously active are more stable than those in which homologous muscles are engaged in an alternating fashion. This may be attributable to the stronger involvement of the dominant motor cortex in ipsilateral hand movements via interaction with the non-dominant motor system, known as neural crosstalk. We used functional magnetic resonance imaging to investigate the neural representation of the interhemispheric interaction during bimanual mirror movements. Thirteen right-handed subjects completed four conditions: sequential finger tapping using the right and left index and middle fingers, bimanual mirror and parallel finger tapping. Auditory cues (3 Hz) were used to keep the tapping frequency constant. Task-related activation in the right primary motor cortex was significantly less prominent during mirror than unimanual left-handed movements. This was mirror- and non-dominant side-specific; parallel movements did not cause such a reduction, and the left primary motor cortex showed no such differential activation across the unimanual right, bimanual mirror, and bimanual parallel conditions. Reducing the contralateral innervation of the left hand may increase the fraction of the force command to the left hand coming from the left primary motor cortex, enhancing the neural crosstalk.

Testing Planar Gas Sensors Based on Yttria-stabilized Zirconia with Oxide Electrodes in the Exhaust Gases of a Spark Ignition Engine

Field measurements of NOx, HCs and CO concentrations on an engine test bench were performed on YSZ-based planar sensors. Sensors with two parallel Pt finger electrodes, one coated withWO3 thick film as sensing electrode, were fabricated. The planar sensor was positioned close to a commercial sensor, downstream the three-way catalytic converter of a FIAT fire 1242 cc spark ignition engine coupled to a dynamometer. The performance of the gas sensors was measured at the stoichiometric air/fuel ratio (A/F∼14.3) and in lean (A/F∼15) and rich (A/F∼13) conditions under different engine regimes (rpm and torque). The response of gas sensors was compared to the response of the commercial probe and related to the exhaust gas concentrations measured by spectroscopic analytical equipment at the engine exhaust end. Preliminary measurements showed promising results in terms of selectivity, sensitivity, stability, reproducibility, and response time.

Nano-structured perovskite oxide electrodes for planar electrochemical sensors using tape casted YSZ layers

Solid-state NO 2 sensors based on yttria stabilized zirconia (YSZ), an O 2- conductor, combined either with an n- (WO 3), or a p-type semiconducting oxide (LaFeO 3), or a mixed electronic and ionic conductor (La 0.8Sr 0.2FeO 3) were investigated. Platinum parallel finger electrodes were applied on the surface of tape-casted YSZ layers and attached with gold wires for current collection. Nanocrystalline perovskite powders were prepared using different chemical methods: LaFeO 3 by the thermal decomposition of the LaFe–hexacyanide complex, and La 0.8Sr 0.2FeO 3 by a sol-gel route. A sub-micrometric commercial WO 3 powder was used. The oxide powders were mixed with a screen-printing oil and deposited on one Pt finger electrode. The presence of the oxide powder makes one of the electrodes different from the other in terms of catalytic activity, specific surface area, gas adsorption and reaction kinetics. Both electrodes were wholly exposed to the same gas atmosphere, without using reference air. The sensors were investigated at fixed temperature (450–700 °C) by measuring the electromotive force (EMF) at different concentrations of NO 2 and CO in air in the range 20–1000 ppm. A fast and stable response was measured for all the tested sensors. An EMF of opposite sign was measured for p- and n-type semiconducting based sensors upon exposure to the same gas. After increasing the grain size of the nano-structured La 0.8Sr 0.2FeO 3 powder by a heat treatment at 900 °C for 4 h, the response to NO x became small, slow and unstable.

Lithologic, structural, and geomorphic controls on ribbon forest patterns in a glaciated mountain environment

So-called “ribbon forests” have been attributed to snowdrift patterns and fire history without reference to geomorphology [Vegetatio 19 (1969) 192.]. This paper illustrates how site conditions of geomorphology and geology explain the origin of ribbon forests. In Glacier National Park, MT (USA), regional tectonic uplift associated with the Laramide Orogeny produced structural features that amplify lithologic differences. Pleistocene glaciation scoured deeply along the strike of bedding planes, highlighting this pattern and in some cases producing fine-scale parallel finger lakes between forested ribbon strips. Twelve ribbon forest sites on both sides of the Continental Divide were closely studied on stereoscopic aerial photographs, and several of these sites were examined in the field or from helicopter overflights. In all cases, geologic and geomorphic conditions explain the location and distribution of the ribbon forests. Change-detection of the distribution of trees versus nontree-covered surfaces in an area of ribbon forest on Flattop Mountain, a complex uplifted synclinal structure, was undertaken using panchromatic, low-altitude aerial photographs from 1966 to 1991. Areas changed from forest to meadow and from meadow to forest in roughly equal amounts in a generally random spatial pattern. No evidence was seen to suggest that the creation of one ribbon eventually created another downwind, as suggested by Billings. Aerial photograph interpretation, field examination and soils analyses of forest ribbons and adjacent unforested meadows clearly illustrated that trees occupy higher, parallel to subparallel, well-drained sites where the spatial pattern is in turn a distinct reflection of the spatial pattern of structure and stratigraphy. Meadows occupy topographically lower positions between ridges where erosion along bedding plane strike was concentrated. Topography sets conditions that allow tree growth in certain locations while precluding it in immediately adjacent areas. Ribbon forests there are thus a spatial manifestation of the interaction between structure, lithology, and topography.

Alternating current distribution in heavy current contacts and conductors of arbitrary shape

In the heavy current disconnecting switches contact system there is a set of parallel finger contacts to eliminate their welding. Alternating current distribution in contacts depends upon their number, material, dimensions, shape, and mutual location. In the paper, the effective numerical method of calculation of alternating current distribution in parallel infinite conductors is proposed within a boundary integral equation method to select these parameters optimally.

Tactile Expert System Using a Parallel Finger Hand with Three-Axis Tactile Sensors.

In order to improve the intelligence of a robot with a tactile sensor, we have discussed basic tactile information, such as slippage and the hardness of a grasped object. In this paper, we produce a tactile expert system which can recognize the material and the shape of the object, and the stability of grasping by means of a reasonable combination of the basic tactile information. Also, in order to discuss the validity of the system, we produced a robot hand which has two plate-type fingers with three-dimensional tactile sensors, and then carried out a series of experiments with the hand and the system. Recognition experiments show that the system can infer seven kinds of objects and that it can control the hand in response to the kinds of instability in grasping.

Measurement of SAW Propagation Properties Using a Laser Probe

Measurements of surface acoustic waves (SAW) propagation properties such as amplitude profiles and phase and group velocities on LiNbO3 have been done using a very stable and highly sensitive laser probe which is a type two-beam interferometer with minimum detectable SAW amplitude 8×10-3 Å at 56 MHz on 127.86° rotating Y-cut LiNbO3. Amplitude profiles are measured for two types of interdigital transducers (IDT) with ten parallel finger pairs and ten circular-arc finger pairs. Results of phase velocity measurements are shown on a table and compared with the literature1) for certain orientations of LiNbO3 or LiTaO3.