Showing papers on "Stylus published in 2020"

STyLuS*: A Temporal Logic Optimal Control Synthesis Algorithm for Large-Scale Multi-Robot Systems:

Abstract: This article proposes a new highly scalable and asymptotically optimal control synthesis algorithm from linear temporal logic specifications, called STyLuS* for large-Scale optimal Temporal Logic S...

Literacy Training of Kindergarten Children With Pencil, Keyboard or Tablet Stylus: The Influence of the Writing Tool on Reading and Writing Performance at the Letter and Word Level

Abstract: During the last years, digital writing devices are increasingly replacing handwriting with pencil and paper. As reading and writing skills are central for education, it is important to know, which writing tool is optimal for initial literacy education. The present training study was therefore set up to test the influence of the writing tool on the acquisition of literacy skills at the letter and word level with various tests in a large sample of kindergarten children (n = 147). Using closely matched letter learning games, children were trained with 16 letters by handwriting with a pencil on a sheet of paper, by writing with a stylus on a tablet computer, or by typing letters using a virtual keyboard on a tablet across 7 weeks. Training using a stylus on a touchscreen is an interesting comparison condition for traditional handwriting, because the slippery surface of a touchscreen has lower friction than paper and thus increases difficulty of motor control. Before training, immediately after training and four to five weeks after training, we assessed reading and writing performance using standardized tests. We also assessed visuo-spatial skills before and after training, in order to test, whether the different training regimens affected cognitive domains other than written language. Children of the pencil group showed superior performance in letter recognition and improved visuo-spatial skills compared with keyboard training. The performance of the stylus group did not differ significantly neither from the keyboard nor from the pencil group. Keyboard training, however, resulted in superior performance in word writing and reading compared with handwriting training with a stylus on the tablet, but not compared with the pencil group. Our results suggest that handwriting with pencil fosters acquisition of letter knowledge and improves visuo-spatial skills compared with keyboarding. At least given the current technological state, writing with a stylus on a touchscreen seems to be the least favorable writing tool, possibly because of increased demands on motor control. Future training studies covering a more extended observation period over years are needed to allow conclusions about long-term effects of writing tools on literacy acquisition as well as on general cognitive development.

A spiral-based inspection path generation algorithm for efficient five-axis sweep scanning of freeform surfaces

Abstract: Traditional inspection of freeform surfaces via three-axis or three ＋ two-axis CMM mainly works in a point-by-point manner where for each inspection point, the stylus of CMM has to approach to and then retract from the surface of inspection, which inevitably drags down (often substantially) the inspection efficiency. Recently, a new inspection apparatus called five-axis inspection machine has emerged, on which the stylus tip can continuously sweep on the part surface and the inspection efficiency can thus be tremendously improved. The crux in using this new inspection technology is how to plan an efficient five-axis inspection path (including both the position and orientation of the stylus). In this paper, we present a new type of five-axis inspection path generation strategy for the inspection of a general freeform surface. Based on the proposed index called Surface Sweep Rate (SSR), an algorithm is designed to partition the surface into a single spiral strip, which maximizes the overall SSR. Then, for this single spiral strip, a five-axis inspection path is generated that takes into consideration the key constraints such as the required smoothness of the probe head trajectory, the sampling density, and the collision-free condition. Physical inspection experiments of our proposed strategy are conducted on two typical freeform surfaces, and the results convincingly confirm the feasibility, effectiveness, and advantages of our new solution.

MagHacker: eavesdropping on stylus pen writing via magnetic sensing from commodity mobile devices

Abstract: Stylus pens have been widely used with today's mobile devices to provide a convenient handwriting input method, but also bring a unique security vulnerability that may unveil the user's handwriting contents to a nearby eavesdropper. In this paper, we present MagHacker, a new sensing system that realizes such eavesdropping attack over commodity mobile devices, which monitor and analyze the magnetic field being produced by the stylus pen's internal magnet. MagHacker divides the continuous magnetometer readings into small segments that represent individual letters, and then translates these readings into writing trajectories for letter recognition. Experiment results over realistic handwritings from multiple human beings demonstrate that MagHacker can accurately eavesdrop more than 80% of handwriting with stylus pens, from a distance of 10cm. Only slight degradation in such accuracy is produced when the eavesdropping distance or the handwriting speed increases. MagHacker is highly energy efficient, and can well adapt to different stylus pen models and environmental contexts.

A Novel Ultrasound Probe Spatial Calibration Method Using a Combined Phantom and Stylus.

Abstract: Intra-operative ultrasound (US) is a popular imaging modality for its non-radiative and real-time advantages. However, it is still challenging to perform an interventional procedure under two-dimensional (2-D) US image guidance. Accordingly, the trend has been to perform three-dimensional (3-D) US image guidance by equipping the US probe with a spatial position tracking device, which requires accurate probe calibration for determining the spatial position between the B-scan image and the tracked probe. In this report, we propose a novel probe spatial calibration method by developing a calibration phantom combined with the tracking stylus. The calibration phantom is custom-designed to simplify the alignment between the stylus tip and the B-scan image plane. The spatial position of the stylus tip is tracked in real time, and its 2-D image pixel location is extracted and collected simultaneously. Gaussian distribution is used to model the spatial position of the stylus tip and the iterative closest point-based optimization algorithm is used to estimate the spatial transformation that matches these two point sets. Once the probe is calibrated, its trajectory and the B-scan image are collected and used for the volume reconstruction in our freehand 3-D US imaging system. Experimental results demonstrate that the probe calibration approach results in less than 1-mm mean point reconstruction accuracy. It requires less than 5 min for an inexperienced user to complete the probe calibration procedure with minimal training. The mockup test shows that the 3-D images are geometrically correct with 0.28°-angle accuracy and 0.40-mm distance accuracy.

Single-shot freeform surface profiler

Abstract: We propose a novel and simple method of single-shot freeform surface profiler based on spatially phase-shifted lateral shearing interferometry. By the adoption of birefringent materials, the laterally shearing waves are simply generated without any bulky and complicated optical components. Moreover, the phase maps that lead to the 3D profile of the freeform surface can be instantly obtained by the spatial phase-shifting technique using a pixelated polarizing camera. The proposed method was theoretically described and verified by measuring several samples in comparison to the measurement results with a well-established stylus probe.

Radular stylus of Cryptochiton stelleri: A multifunctional lightweight and flexible fiber-reinforced composite

Abstract: Chitons are herbivorous invertebrates that use rows of ultrahard magnetite-based teeth connected to a flexible belt (radula) to rasp away algal deposits growing on and within rocky outcrops along coastlines around the world. Each tooth is attached to the radula by an organic structure (stylus) that provides mechanical support during feeding. However, the underlying structures within the stylus, and their subsequent function within the chiton have yet to be investigated. Here, we investigate the macrostructural architecture, the regional material and elemental distribution and subsequent nano-mechanical properties of the stylus from the Northern Pacific dwelling Cryptochiton stelleri. Using a combination of μ-CT imaging, optical and electron microscopy, as well as elemental analysis, we reveal that the stylus is a highly contoured tube, mainly composed of alpha-chitin fibers, with a complex density distribution. Nanoindentation reveals regiospecific and graded mechanical properties that can be correlated with both the elemental composition and material distribution. Finite element modeling shows that the unique macroscale architecture, material distribution and elemental gradients have been optimized to preserve the structural stability of this flexible, yet robust functionally-graded fiber-reinforced composite tube, providing effective function during rasping. Understanding these complex fiber-based structures offers promising blueprints for lightweight, multifunctional and integrated materials.

Watch my Painting: The Back of the Hand as a Drawing Space for Smartwatches

Abstract: Smartwatches can be used independently from smartphones, but input tasks like messaging are cumbersome due to the small display size. Parts of the display are hidden during interaction, which can lead to incorrect input. For simplicity, instead of general text input a small set of answer options are often provided, but these are limited and impersonal. In contrast, free-form drawings can answer messages in a very personal way, but are difficult to produce on small displays. To enable precise drawing input on smartwatches we present a magnetic stylus that is tracked on the back of the hand. In an evaluation of several algorithms we show that 3D position estimation with a 7.5x20mm magnet reaches a worst-case 6% relative position error on the back of the hand. Furthermore, the results of a user study are presented, which show that in the case of drawing applications the presented technique is faster and more precise than direct finger input.

Optimal Control for Electromagnetic Haptic Guidance Systems

Abstract: We introduce an optimal control method for electromagnetic haptic guidance systems. Our real-time approach assists users in pen-based tasks such as drawing, sketching or designing. The key to our control method is that it guides users, yet does not take away agency. Existing approaches force the stylus to a continuously advancing setpoint on a target trajectory, leading to undesirable behavior such as loss of haptic guidance or unintended snapping. Our control approach, in contrast, gently pulls users towards the target trajectory, allowing them to always easily override the system to adapt their input spontaneously and draw at their own speed. To achieve this flexible guidance, our optimization iteratively predicts the motion of an input device such as a pen, and adjusts the position and strength of an underlying dynamic electromagnetic actuator accordingly. To enable real-time computation, we additionally introduce a novel and fast approximate model of an electromagnet. We demonstrate the applicability of our approach by implementing it on a prototypical hardware platform based on an electromagnet moving on a bi-axial linear stage, as well as a set of applications. Experimental results show that our approach is more accurate and preferred by users compared to open-loop and time-dependent closed-loop approaches.

28.1 A Capacitive Touch Chipset with 33.9dB Charge-Overflow Reduction Using Amplitude-Modulated Multi-Frequency Excitation and Wireless Power and Data Transfer to an Active Stylus

Abstract: As the demand for high frame rate and SNR increases in capacitive touch systems (CTSs), several driving methods have been reported [1], [5]. However, when excitation circuits simultaneously send excitation signals V EXT s to multiple TX electrodes in order to increase frame rate, the readout circuit suffers from charge overflow because of the superposition of V EXT s. To prevent this, driving methods such as time-division [1], [5] and reduced-amplitude excitation [3], and signal omitting and linear interpolation in the digital domain [4] have been adopted in AFE ICs, but they degrade the frame rate, and SNR, and increase the computational load of the CTS, respectively. In this paper, amplitude-modulated multiple-frequency excitation (AM-MFE) is used to prevent charge overflow without degrading the frame rate, SNR, and computational load. In addition, an electric pencil case (EPC) is proposed for wireless power and data transfer to an active stylus, so as to avoid the need to replace the battery of the stylus or charge it via an adapter.

Line-Storm Ludic System: An Interactive Augmented Stylus and Writing Pad for Creative Soundscape

Abstract: We present Line-Storm, an interactive computer system for creative performance. The context we investigated was writing on paper using Line-Storm. We used self-report questionnaires as part of research involving human participants, to evaluate Line-Storm. LineStorm consisted of a writing stylus and writing pad, augmented with electronics. The writing pad was connected to a contact microphone, and the writing stylus had a small micro-controller board and peripherals attached to it. The signals from these electronic augmentations were fed into the audio-synthesis environment Max/MSP to produce an interactive soundscape. We attempted to discover whether Line-Storm enhanced a self-reported sense of being present and engaged during a writing task, and we compared Line-Storm to a noninteractive control condition. After performing statistical analysis in SPSS, participants reported they were, on average, no more present and engaged during the experimental condition than during the control condition. As creativity is subtle, and varies with person, time, context, space and so many other factors, this result was somewhat expected by us. A statistically significant result of our study is that some participants responded to Line-Storm more positively than others. These Preservers of Line-Storm were a group, distinct from other participants, who reported greater presence and engagement and who wrote more words with LineStorm and during the control condition. We discuss the results of our research and place Line-Storm in an artistic-technological context, drawing upon writings by Martin Heidegger when considering the nature of Line-Storm. Future work includes interesting, immerPermission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. sive, and engaging interactive soundscape for writing or drawing performance, modifying interactive components, improving aesthetics, using more miniaturized electronics, and experimenting with a drawing task instead of a writing task.

Design and Construction of a Low-Force Stylus Probe for On-machine Tool Cutting Edge Measurement

Abstract: A new on-machine profiler employing a cantilever beam was proposed and developed to measure the sharp micro-cutting edges of precision cutting tools with low measuring force of 0.1 mN. The proposed profiler consists of a probe unit and a positioning unit. The probe unit employs a stylus mounted on the free end of a hollow triangular cantilever beam and a laser displacement sensor to detect the deflection of the cantilever beam. The positioning unit consists of two single-axis DC servo motor stages for precise positioning of the probe unit. The cantilever is designed with the assistance of the finite element method. In order to demonstrate the feasibility of the proposed measurement system, experiments are conducted and the measurement result for a micro-cutting edge is compared with that by a commercial profiler. Furthermore, a method to compensate for the measurement error caused by the lateral displacement of the cantilever beam is proposed. The compensated measurement results show good agreement within ± 2 μm with those obtained by the commercial profiler.

Surface characterization of paper and paperboard using a stylus contact method

Abstract: Abstract Surface characterization is important and has many applications in the paper industry. Surface characterization requires both surface roughness and surface friction. The relationship between the two has not been fully established for paper and paperboard. It has been a common practice that only the average property and the standard deviation with the coefficient of variation (COV) are reported for surface roughness and friction measurements. This practice, however, provides few information on surface structure and can lead to wrong judgments because two samples having the same average and the COV can have different physical properties. To avoid such mistake, a new surface characterization method has been developed. To this end, surface roughness- and friction-profiles have been obtained using a latest version of Kawabata surface tester (Model: KES-SESRU, Kato Tech, Kyoto Japan). This new version uses the same stylus for both measuring surface roughness and friction under the same operating conditions. It was found that a correlation between the surface roughness and surface friction was very low. This indicates that they should be independent of each other. Therefore, both should be determined for surface characterization.

On-machine profile measurement of a micro cutting edge by using a contact-type compact probe unit

Abstract: A new contact-type on-machine measurement system is designed and developed for the evaluation of a micro cutting edge profile. The measurement system is composed of a compact probe unit having a sharp stylus mounted on a flexible beam, an inner displacement sensor for the detection of the stylus displacement, and a two-axis precision positioning system. For the evaluation of tool faces having a steep slope, a new probing procedure with the enhancement of the inner displacement sensor integrated into the probe unit is newly proposed. After the design and development of the probe unit, the feasibilities of the developed measurement system and the proposed probing procedure are demonstrated through some basic experiments. Regarding the out-of-straightness and angular error motion of the two-axis positioning system employed in the developed measurement system, a pair of length gauges is newly employed to reduce the influences of error motions of the stage system. The topographic profile of the micro cutting edge obtained by the measurement system with the modified probe unit is then compared with those obtained by a commercial stylus profiler and a laser confocal microscope. The feasibility and effectiveness of the developed on-machine tool edge profile measurement system are also demonstrated through uncertainty analysis based on the GUM with the Monte-Carlo method.

Arc-Type and Tilt-Type: Pen-based Immersive Text Input for Room-Scale VR

Abstract: As immersive, room-scale virtual and augmented reality become more utilized in productive workflows, the need for fast, equally-immersive text input grows. Traditional keyboard interaction in these room-scale environments is limiting because of its predominantly-seated usage and the necessity for visual indicators of the hands and keys potentially breaking immersion. Pen-based VR/AR interaction presents an alternative immersive text input modality with high throughput. In this paper, we present two novel interfaces designed for a pen-shaped stylus that do not require the positioning of the controller within a region of space, but rather detect input from rotation and on-board buttons. Initial results show that compared with Controller Pointing text entry techniques, Tilt-Type was slower but produced fewer errors and was less physically demanding. Additional studies are needed to validate the results.

Development of a laser-guiding-type deep small-sized hole-measurement system: Measurement accuracy

Abstract: In this study, a system for measuring small-sized holes with a 17–21 mm diameter and 1000 mm length was constructed. The system comprises a laser interferometer to detect hole accuracy, a probe connected to a measurement bar, and an optical apparatus for detecting the probe attitude (position and inclination). The probe was supported by supporting pads. A steel workpiece with 18 -mm diameter and 800 mm length was used for the performance test. During the experiment, errors were found in terms of hole deviation and roundness profile. Further experiments, using new experimental apparatus and analysis, revealed the causes of errors: electrical noise that increased with time, two periodic stylus swings in the longitudinal direction of the hole per rotation of the measurement unit, and the excessive spring force pushing the tip of the stylus, causing a large frictional force with the hole wall, etc. If these errors are corrected, high accuracy in the measurement of hole deviation and roundness can be achieved.

Tracking of Flexible Brush Tip on Real Canvas: Silhouette-Based and Deep Ensemble Network-Based Approaches

Abstract: Digital painting is a process of creating a digital artwork using modern human-computer interaction technologies One of the core enabling technologies is the real-time tracking of user's strokes, which is generally supplied by a digital tablet with a stylus While the digital tablet technology provides highly accurate tracking, the drawing should be done with a rigid stylus on a plastic surface This sometimes destroys the realism of drawing, such as interaction with the digital tablet cannot provide the feedback of subtle texture, friction of the paper/fabric canvas and tension of soft painting brush This becomes particularly problematic for traditional painting artists who are trained with and prefer real painting brush and paper/fabric canvas Thus, the aim of this work is to present an alternative solution where the user's strokes can be tracked even when the actual brush and canvas are used To this end, we proposed two approaches for digitally tracking the tip of flexible bristles of a soft brush, so that the painting can be created digitally on a computer The first approach captures the silhouette of deforming bristles using a pair of well-aligned infra-red (IR) cameras, which extracts the tip from the silhouette, and reconstructs the 2D position of the tip The second approach predicts the brush tip position through a deep ensemble network-based approach where the relationship between the brush tip position and brush handle pose are trained with our novel model comprising of Long-Short Term Memory Autoencoder and 1-D Convolutional Neural Network The trained model is used to predict the brush tip position in realtime Both approaches extensively evaluated through multiple tests Furthermore, our model outperforms the state-of-the-art models

VnStylus : A Haptic Stylus With Variable Tip Compliance

Abstract: Variable stiffness tools have been shown to be advantageous for ensuring safety and improving stability, dynamic performance and energy efficiency of interaction tasks. In this article, we present the design, mathematical modeling, implementation, characterization and user evaluations of VnStylus , a stylus with hardware-based tip compliance modulation. The stiffness modulation of the stylus tip is achieved through transverse stiffness variations of axially loaded beams. This approach of mechanically-controlled stiffness variation is advantageous for a variable stiffness stylus, as it can be implemented using a fully compliant mechanism that alleviates the problem of friction forces dominating under miniaturization and allows for high fidelity stiffness display even for very low stiffness values. Thanks to its hardware-based impedance modulation, the device does not suffer from the bandwidth and the stable impedance rendering limitations of software-based impedance control strategies. Featuring a manual adjustment mechanism, the device does not necessitate actuators, sensor or electronics; hence, is lightweight, low cost, and robust. Experimental characterizations verify the large range of stiffness modulation that can be achieved and the accuracy of the equivalent stiffness model of the system. Human subject experiments provide evidence of the efficacy of the modulated stylus stiffness on human performance during several common interactions with styli.

Design of Three-dimensional Isotropic Microprobe Based on Three-Flexible-Hinge Suspension for Measurement of Microstructures

Abstract: To enhance the precision manufacturing of microstructures, a 3-D isotropic microprobe based on three-flexible-hinge suspension and orthogonal microball collimation was developed. First, the sensing principle of the microprobe was investigated by analyzing its displacement transfer principle and the displacement measurement principle of the orthogonal microball collimation optical paths. Second, the stiffness model of the microprobe at the tip was established by considering the influence of the measuring stylus stiffness. Subsequently, the isotropic design of the microprobe was developed in terms of the 3-D isotropic stiffness and sensitivity. Utilizing the rotation and translation of the three-flexible-hinge suspension, the 3-D tip displacements were transformed into the 3-D displacements of the microball of the transfer stylus which was fixed in the reverse coaxial direction to the measuring stylus, then the 3-D displacements of the microball were transformed into centroid position shifts of the light spots by the orthogonal microball collimation optical paths. Finally, a 3-D isotropic microprobe was fabricated, and experiments to verify its performance for measurements pertaining to microholes and microsteps were conducted. A method for the effective measurement of microholes was established, which could improve the measurement efficiency, and the tilt angle of the countertop was considered for the measurement of the microsteps. The experimental results indicated that the proposed microprobe could help realize low measurement force, 3-D isotropic measurement of microstructures, and improvement of the measurement accuracy.

Quantifying abrasive-blasted surface roughness profiles using scanning electron microscopy

Abstract: Rough surface profiles are specified for metal surfaces so that corrosion preventative coatings adhere well and provide long-term protection. Simple stylus scans and replica tape are widely used in industry to characterize surfaces and control the quality of surface preparation. Unfortunately, a scientific, quantitative connection between adhesion and surface profile parameters remains unclear. Stereo-pair images from scanning electron microscopy, SEM, were used to digitally reconstruct and then characterize 3D surfaces, which is a technique that seems previously unreported in coatings applications. SEM results were consistent with those from a stylus profilometer, but the data from a surface scan are much more numerous than from a line scan, and SEM can provide very high magnifications. 3D surfaces at high magnification gave larger values for the increase in area developed by the abrasive blasting than were determined at lower magnifications and by the stylus profilometer. Nevertheless, both techniques showed that the surface roughness height and ramification was far less than might be expected from illustrations in the existing literature on coatings’ adhesion. Quantified characterization, with details shown at high magnification, may provide scientific insight into how the various features of a roughened surface enhance the adhesion of protective coatings.

Visuo-Haptic Mixed Reality Simulation Using Unbound Handheld Tools

Abstract: Visuo-haptic mixed reality (VHMR) adds virtual objects to a real scene and enables users to see and also touch them via a see-through display and a haptic device. Most studies with kinesthetic feedback use general-purpose haptic devices, which require the user to continuously hold an attached stylus. This approach constrains users to the mechanical limits of the device even when it is not needed. In this paper, we propose a novel VHMR concept with an encountered-type haptic display (ETHD), which consists of a precision hexapod positioner and a six-axis force/torque transducer. The main contribution is that the users work with unbound real-life tools with tracking markers. ETHD’s end-effector remains inside the virtual object and follows the tooltip to engage only during an interaction. We have developed a simulation setup and experimentally evaluated the relative accuracy and synchronization of the three major processes, namely tool tracking, haptic rendering, and visual rendering. The experiments successfully build-up to a simple simulation scenario where a tennis ball with a fixed center is deformed by the user.

Electromagnetic Haptic Feedback System for Use With a Graphical Display Using Flat Coils and Sensor Array

Abstract: We have developed a haptic interaction system which wirelessly generates 3D forces onto a small magnet which can be fixed to a user's fingertip or a handheld stylus. Magnet position sensing and haptic force generation can both be performed through a thin screen, and the actuation and sensing components of the system are sufficiently thin and compact to be easily mounted behind the screen in the same enclosure. In this manner, the system is particularly well suited for use for co-located haptic and graphic display, with 3D force feedback added to an interactive display. The purpose of the work is to describe, analyze, and validate a method and device to generate haptic force feedback on a magnet held near a display screen using thin flat arrays of coils and sensors. The location of the magnet during haptic interaction is obtained by an array of Hall effect sensors. Flat rectangular coils are used to generate Lorentz forces on the interaction magnet and can act in combination to produce 3D forces in any direction, both parallel and normal to the screen surface. The active area of the haptic interaction system prototype is approximately 120 × 120 mm, with effective force generation and position sensing from the screen surface to an elevation of approximately 15 mm. The localization methods do not depend on the size, shape, or magnetization strength of the magnet, so that larger or smaller magnets may be used for greater forces or more ease of manipulation, without modifying the software other than the force actuation model. The design of the system is presented, including modeling and analysis of the sensing and actuation methods. Experimental results are given for field sensing, magnet localization, and haptic interaction with simulated objects. Forces up to 0.3 N are demonstrated to be generated in different specific desired directions while sensing planar magnet position to an accuracy within approximately 2.0 mm.

Handwriting behavior as a self-confidence discriminator

Abstract: Receiving feedback based on the combination of self-confidence and correctness of an answer can help learners to improve learning efficiency. In this study, we propose a self-confidence estimation method using a simple touch up/move/down events that can be measured in a classroom environment. We recorded handwriting behavior during the answering vocabulary questions with a tablet and a stylus pen, estimating self-reported confidence. We successfully built a method that can predict the user's self-confidence with a maximum of 73% accuracy.