Displacement Range Research Articles

Optimization Design and Experimental Study of Solid Particle Spreader for Unmanned Aerial Vehicle

This study designed and investigated a solid particle spreader, as well as parameter optimization and experimental for a groove wheel, to mitigate the problems of low uniformity and poor control accuracy of solid particulate material UAV spreading. The discrete element method was used to simulate and analyze the displacement range and stability of each grooved wheel at low speeds. Furthermore, orthogonal regression and response surface analyses were used to analyze the influence of each factor on the stability of the discharge rate and pulsation amplitude. The results showed that the helix angle, sharpness, and length of the groove significantly influenced the application performance, whereas the number of grooves had no significant influence. The groove shape was eccentric, the helix angle was 50°, the length was 35 mm, and the number of grooves was 7. Additionally, the bench test results showed that in the range of 10–60 rpm, the relative deviation of the discharging rate between the simulation and bench test is from 0.47% to 10.39%, and the average relative deviation is 3.93%. Between the groove wheel rotation speed and discharge rate, R2 was 0.991, and the adjustable range of the discharge amount was between 3.68 and 23.43 g/s. The minimum and maximum variation coefficients of the average discharge rate among individual applicators were 1.01% and 2.79%, respectively, whereas the standard deviations were 0.09 and 0.46 g/s, respectively. In conclusion, the discharge stability and adjustable range of the spreader using the optimized groove wheel satisfied the requirements for solid particulate material discharge.

Some measures to enhance the energy output performances of triboelectric nanogenerators

Abstract Triboelectric nanogenerators (TENGs) have been developed as innovative devices for harvesting various forms of mechanical energy generated by our bodies and surroundings, which provide green and sustainable power for increasingly miniaturized and mobile electronics, especially wearables. In this article, the largest possible output energy per cycle of a TENG in the two basic working modes, namely, the vertical contact-separation (CS) mode and the contact-sliding (LS) mode, is analyzed and the energy collected by a capacitor is tested. It is found that more energy output and collected from a vertical CS mode TENG than that from a LS mode TENG with the same size and triboelectric layer materials when the size and displacement range of the TENG are suitable for a wearable energy harvesting device. In order to improve the energy output of a TENG, three methods have been proposed to increase its surface charge density, such as adding a BaTiO3 film or a polydimethylsiloxane (PDMS)-BaTiO3 composite film between the triboelectric layer and the metal electrode, and using a PDMS-BaTiO3 composite film as a negative triboelectric layer, and corresponding TENGs are fabricated for experimental testing. These measures have effectively enhanced the output of the TENGs.

Research on response characteristics of loess slope and disaster mechanism caused by structural plane extension under excavation

Geological disasters occur frequently in the Loess Plateau due to the joint fissures in the strata and human engineering activities. Against this background, the deformation and failure mode of the loess slope with the structural plane under excavation and the extension mechanism of the structural plane are analyzed and summarized. The results showed that: (1) Through the physical model test, the deformation failure mode of the slope is summarized as the tension-splitting, pressure-sliding shallow failure. The collapse failure process is defined as four stages: Compression deformation, creep deformation, slip deformation and slip failure. (2) Slope displacement is concentrated beneath the pressure plate, increasing linearly under load conditions but becoming nonlinear after excavation conditions. As the excavation angle rises, the displacement range along the structural plane gradually extends toward the slope toe. The displacement time-history curve shows three stages: The lifting load stage, the cumulating deformation stage, and the sliding failure stage. (3) The stress redistribution caused by excavation, prompting deformation and potential failure. As internal stress nears the soil strength limit, human-induced disturbances exacerbate stress redistribution, leading to accumulated stress. Finally released through deformation and cracking. Each excavation condition modifies the original loading transfer path, driving stress redistribution at the slope surface and at the structural plane’s tip. (4) The sudden drop in stress level and sudden rise of accumulated settlement are the characteristics of slope sliding failure. The position of the structural plane determines the position of the slope sliding surface. (5) According to the external characterization of the structural plane, the extension process of the structural plane can be defined as four stages: Initiation of crack extension, classification deformation, subsection extension and compression sealing. According to the extension of the structural plane, the spreading cracks of the slope’s internal structural plane are defined as two types: Fractured cracks and shear cracks.

Numerical Analysis of the Vehicle Damping Performance of a Magnetorheological Damper with an Additional Flow Energy Path

Vehicles experience various frequency excitations from road surfaces. Recent research has focused on active dampers that adapt their damping forces according to these conditions. However, traditional magnetorheological (MR) dampers face a “block-up phenomenon” that limits their effectiveness. To address this, additional flow-type MR dampers have been proposed, although revised designs are required to accommodate changes in damping force characteristics. This study investigates the damping performance of MR dampers with an additional flow path to enhance the vehicle ride quality. An optimization model was developed based on fluid dynamics equations and analyzed using electromagnetic simulations in ANSYS Maxwell software. Vibration analysis was conducted using AMESim by applying a sinusoidal road surface model with various frequencies. Results show that the optimized diameter of the additional flow path obtained from the analysis was 1.1 mm, and it was shown that the total damping force variation at low piston velocities decreased by approximately 56% compared to conventional MR dampers. Additionally, vibration analysis of the MR damper with the optimized additional flow path diameter revealed that at 30 km/h, 37.9% acceleration control was achievable, at 60 km/h, 18.7%, and at 90 km/h, 7.73%. This demonstrated the resolution of the block-up phenomenon through the additional flow path and confirmed that the vehicle with the applied damper could control a wider range of vehicle upper displacement, velocity, and acceleration compared to conventional vehicles.

Mechanical behavior analysis of sandwich composite structures with different core geometries under three-point bending

This study presents a comprehensive investigation into the mechanical behavior of sandwich composite structures featuring six distinct core geometries under three-point bending conditions. Through detailed finite element analysis (FEA), the research examines the performance characteristics of I-shaped, traditional honeycomb (NIDA), O-shaped, X-shaped, semi-circular, and modified core geometries. The analysis focused on stress distribution patterns, displacement responses, and overall structural integrity. Results demonstrate that the semi-circular core geometry exhibits superior mechanical properties, achieving an 84.66% improvement in positive stress resistance and 74.79% enhancement in negative stress resistance compared to the traditional honeycomb reference model. The study revealed consistent linear elastic behavior across all models within the tested displacement range, with the semi-circular configuration showing optimal stress distribution and minimal core deformation. Using aluminum for facings and core materials, the research evaluated mechanical responses through displacement-controlled loading conditions, measuring stress concentrations at critical points and analyzing deformation patterns. This research provides valuable insights into the relationship between core geometry and mechanical performance, offering practical implications for engineering applications requiring high strength-to-weight ratios and enhanced flexural resistance in modern structural design.

Finite‐Element Analysis of an Antagonistic Bistable Shape Memory Alloy Beam Actuator

A finite‐element (FE) analysis of the active bistability of an antagonistic shape memory alloy (SMA) beam actuator of TiNiCu is presented. The actuator comprises two coupled SMA beams that are clamped at both ends and coupled in their center by a spacer having different memory shapes being deflected in opposite out‐of‐plane directions. The actuator is characterized by two equilibrium positions. To determine bistable behavior as a function of geometrical parameters, a force criterion is defined by the coupling force of the beams in austenitic and martensitic states. Bistable behavior is achieved, if the coupling force does not change sign in the entire displacement range. This implies that the austenitic beam dominates the opposing martensitic beam. Thus, selective heating of the SMA beams results in a snap‐through motion of the coupled SMA beams. Depending on which of the two beams is in austenitic state, either of the two equilibrium positions is reached without the need for an external force. It is demonstrated that geometrical parameters like initial predeflection and spacer length have a crucial effect on the bistable performance. Bistable regions as well as critical limits characterized by geometry‐dependent stability ratios, beyond which the actuator's performance becomes monostable, are identified.

Realtime and noninvasive assessment of endotracheal tube displacement using near-infrared and visible cameras.

Endotracheal tube (ETT) intubation is a medical procedure routinely used for achieving mechanical ventilation in critically ill patients. Appropriate ETT placement is crucial as undetected tube migration may cause multiple complications or even fatalities. Therefore, prompt detection of unplanned movement of the ETT and immediate action to restore proper placement are essential to ensure patient safety. Despite this necessity, there is not a widely adopted tool for real-time assessment of ETT displacement. We have developed a device, a dual-camera endotracheal tube or DC-ETT, to address this unmet clinical need. This device uses a near-infrared (NIR) LED and a side-firing optical fiber embedded in the side of an ETT to light up the tracheal tissue and a visible and NIR camera module for the displacement detection. The NIR camera tracks the movement of the NIR pattern on the skin, while the visible camera is used to correct the body movements. The efficacy of the DC-ETT was assessed in two piglets with a linear displacement sensor as reference. A mean discrepancy of less than 0.5 mm between the DC-ETT and reference sensor was observed within a displacement range of ±15 mm. The results suggest that the DC-ETT can potentially provide a simple and cost-effective solution for real-time monitoring of ETT displacements in operating rooms, intensive care units, and emergency departments.

A novel method for identifying rock interfaces and fragmentation zones based on drilling response characteristics

The rapid measurement and acquisition of the fracture characteristics and strength of the surrounding rock are crucial for evaluating the stability of underground engineering. In this study, a laboratory/coal mine universal drilling test platform was developed to enable real-time measurement of drilling parameters. The testing results demonstrate that under identical rotation speed conditions, both thrust force and torque increase exponentially with increasing drilling speed, while under identical drilling speed conditions, both thrust force and torque decrease linearly with increasing rotation speed. In intact rock layers, variations in torque, thrust force, and drilling speed with depth remain relatively stable, in rock layer interfaces and fragmentation zones, sudden changes occur within a drill displacement range of approximately 3–7 mm, which become more pronounced as strength differences between adjacent rock layers increase.Based on the cutting mechanics model of drill bit, the evaluation index of drilling energy consumption of unit rock mass (Eη) is derived. Subsequently, based on drilling speed, rotation speed, thrust force, torque and energy index, a machine learning model for predicting rock strength is established using the LS-SVM nonlinear regression approach. Field practice has shown that drilling platform can effectively identify both the rock interface and range of fragmentation areas. The experimental results are of great value to the selection of supporting types in the process of coal mine roadway excavation.

Finite element study on the mechanism of the influence of pretension force and block strength on the shear resistance of the anchor cable with C-shaped tube

To prevent the early breakage of anchor cables under shear loads in support engineering, a combined structure of Anchor Cable with C-shaped Tube (ACC) has been proposed. The shear resistance enhancement mechanism of this structure and the mechanisms of various influencing factors have yet to be fully revealed. A refined nonlinear finite element model of ACC was original established using ABAQUS software, taking into account the actual structure of the steel strands and the interactions, such as contact and failure between the various components. Various anchor cable pretension forces and block strengths were set to investigate their effects on the shear mechanical response of ACC. The results successfully demonstrated a high correlation between peak shear load and pretension force. The results demonstrate that an increase in pretension force reduces the ACC’s peak shear load and break displacement. Additionally, the structure exhibited higher flexural stiffness, the block strength was mobilized earlier, and the block failed locally more quickly. Under high pretension forces, the system exhibited higher shear stiffness in the early stages of shearing due to the influence of the axial force component. With low pretension forces, the ACC exhibited a larger break displacement due to the minor tensile deformation at the shear plane position for the same shear displacement. At low pretension forces, the structure’s bending angle increased more rapidly during the middle and later stages of shearing, accompanied by a larger break displacement. Both of these factors led to a greater bending angle at the shear plane position at the point of failure. The results reveal the characteristic of the peak shear load initially increasing and then decreasing with the increase in test block strength, along with its underlying mechanism. As the block strength increased, the bending angle of the structure at the shear plane position increased more rapidly, resulting in higher shear stiffness. With high block strength, the combination of smaller break displacement and greater shear stiffness led to an initial increase followed by a decrease in peak shear load. A comprehensive RSSB (Relative Stiffness between Structure and Test Block) that considers both structural and test block stiffness was proposed. The deformation pattern of the structure was controlled by the RSSB. The higher the RSSB, the wider the plastic hinge extension range for the same shear displacement, the smaller the bending angle at the shear plane position, and the smaller the maximum curvature of the structure. The contact force of the C-shaped tube generally exhibited a “single peak” distribution. As the shear displacement increased, the peak position of the contact force moved away from the shear plane, and the maximum contact force increased rapidly and remained relatively stable. At the end of the shearing process, the contact force of the C-shaped tube exhibited a “double peak” distribution.

Introduction of a novel longitudinal-flexural-torsional actuator using a magnetostrictive rod

Abstract This paper presents a novel bulk magnetostrictive actuator, utilizing a rod made of Permendur alloy. This actuator demonstrates versatility in accommodating longitudinal, torsional, and flexural deformations. Longitudinal deformation is induced by applying magnetic fields along the material’s axis, exploiting the Joule effect. The axial magnetic field is generated by a coaxial coil surrounding the material. Torsional deformation is achieved by passing current through the magnetostrictive material and applying circumferential magnetic field, following the Wiedeman effect. To induce flexural deformation, a magnetic field is applied at the material’s surface, facilitated by a magnetic coupler. Actuation is executed using DC magnetic fields, granting the actuator control over four degrees of freedom. Numerical analysis conducted utilizing COMSOL software, showed the combined modes and their mutual influences. The actuator’s displacement range reaches a maximum of 12 µms longitudinally, 7 µms flexurally, and 0.15 degrees torsionally. It also exhibits the capability of simultaneous excitation in two or three different modes. The experiments and studies conducted show the potential application of this innovative actuator in precise positioning systems such as microscopes and optical systems.

Design of non‐contact capacitive displacement detection methods for magnetic levitated sphere

AbstractTo meet the demand for non‐contact displacement detection of magnetic levitation spheres, single‐ended and differential variable electrode distance capacitance displacement detection schemes are designed in this paper. For these two schemes, finite element simulation models are established in COMSOL Multiphysics software to obtain the relationship between the test capacitance and the displacement of the magnetic levitation sphere. In the single‐ended scheme, there is a non‐linear relationship between the test capacitance and the position of the levitated sphere, and this non‐linearity becomes more significant as the sphere moves away from the electrode plate. In contrast, in the differential scheme, the test capacitance and the displacement of the levitated sphere follow a linear relationship, but the test sensitivity decreases with the expansion of the measuring range. The simulation results of the differential scheme have been verified by building a spherical displacement detection simulator, and thanks to the mature development of capacitive detection circuits, the scheme is expected to achieve better than nanoscale displacement detection resolution in the 6.6 mm displacement range of a magnetic levitation sphere in the future.

Sexual differetiation of Rhodiola rosea L. populations in the high-mountain zone of the Ukrainian Carpathians

Background. Individual (morphological) and group parameters (the number of male and female individuals, their sex ratio, and the range of sex ratio displacement) are an important indicator of sexual differentiation of Rhodiola rosea L. populations. To date, indicators of these parameters in natural plant populations have not been studied sufficiently. Therefore, for the analysis of the state of the populations of the species, it is important to study the parameters of their sexual differentiation and the main trends of changes that affect the ability to recover in high-mountain conditions. Methods. In order to obtain data, conventional stationary and route-based research methods were used. To record individuals of different sexes, long-term monitoring plots were used, which were laid in the characteristic habitats of the species’ populations in 2000–2022. The ratio of male and female individuals is determined based on their quantitative distribution per unit area. The sexual potential index that determines the proportion of females and their participation in generative reproduction was used. Results. The main differences in the morphological and quantitative parameters of male and female individuals in high-mountain conditions were determined. It was found that a characteristic feature during long-term research is a decrease in the number of generative individuals of both male and female sexes. In the studied populations, there is a shift in the sex ratio towards males (73 %) and this trend has been maintained over the last dozen of years. Therefore, the number of females compared to males is very small, which affects the sexual potential of populations. Conclusions. The ratio of male and female individuals, the range of its displacement and potential participation in the realization of sexual potential in R. rosea was determined. The present study showed that the general trend in the populations of the species is a decrease in the number of female individuals. Male biased sex ratio has an impact on sexual potential and ability to generative reproduction.

Design of broad quasi-zero stiffness platform metamaterials for vibration isolation

Adaptability and reliability are challenges in designing vibration isolation structures, and mechanical metamaterials featuring broad quasi-zero stiffness (QZS) platforms are among the most promising candidates for addressing this issue. This paper proposes a novel design of vibration isolation metamaterials featuring a broad QZS platform to achieve vibration control in complex environments. The metamaterial unit cells are designed by integrating horizontal and diagonal beams based on the mechanism combining Euler buckling and flexural deformation. Herein, the component made of diagonal beams is configured to exhibit negative stiffness behavior, while the designed support components aim to relax the boundary constraints of the diagonal beam component, thereby mitigating the negative stiffness effect. By tuning the synergistic effects between horizontal and diagonal beams, QZS features can be achieved over a broad range of displacements. A combination of theoretical analysis, finite element method and experiment is employed to investigate the payload and QZS features of metamaterials comprehensively. Notably, the designed unit cell maintained a considerably broad QZS platform, with static experiments revealing that this platform accounts for approximately 55 % of the total loading range. Furthermore, the designed metamaterials exhibit excellent vibration isolation performance in the low-frequency range, with vibration experiments demonstrating that the unit cell can effectively shield vibrations across almost the entire range when the support mass corresponds to the QZS payload. The geometric parameters of the metamaterial configuration that influence the range of the QZS platform are also explored. In conclusion, the proposed mechanical metamaterials have a tunable and broad QZS platform with considerable potential for use in customized low-frequency vibration isolation applications.

The impact mechanisms of intermediate water depth on the coupled dynamic responses of large-capacity floating wind turbines

ABSTRACT The currently planned floating wind farms in China mostly have water depths in the intermediate range. Therefore, investigating the impact mechanisms of intermediate water depths on the coupled dynamic responses of floating wind turbines is of significant importance. In comparison to deep water, mooring systems in intermediate water depths are more prone to experiencing catenary shape loss and stiffness. The contribution of difference-frequency effects increases with decreasing water depth, resulting in a more substantial impact on low-frequency responses. The Full Quadratic Transfer Function (QTF) method accurately captures low-frequency responses. Placing clump weights in the bottom section of the mooring line effectively restricts the displacement range of floating turbines while maintaining average fairlead tensions at levels similar to the other two forms. On this basis, focusing on the most optimal mooring system performance, experiments were conducted to validate the coupled dynamic responses of floating wind turbines in intermediate water depths.

3D morphology of an outer-hair-cell hair bundle increases its displacement and dynamic range

In mammals, outer-hair-cell hair bundles (OHBs) transduce sound-induced forces into receptor currents and are required for the wide dynamic range and high sensitivity of hearing. OHBs differ conspicuously in morphology from other types of bundles. Here, we show that the 3D morphology of an OHB greatly impacts its mechanics and transduction. An OHB comprises rod-like stereocilia, which pivot on the surface of its sensory outer hair cell. Stereocilium pivot positions are arranged in columns and form a V shape. We measure the pivot positions and determine that OHB columns are far from parallel. To calculate the consequences of an OHB’s V shape and far-from-parallel columns, we develop a mathematical model of an OHB that relates its pivot positions, 3D morphology, mechanics, and receptor current. We find that the 3D morphology of the OHB can halve its stiffness, can double its damping coefficient, and causes stereocilium displacements driven by stimulus forces to differ substantially across the OHB. Stereocilium displacements drive the opening and closing of ion channels through which the receptor current flows. Owing to the stereocilium-displacement differences, the currents passing through the ion channels can peak versus the stimulus frequency and vary considerably across the OHB. Consequently, the receptor current peaks versus the stimulus frequency. Ultimately, the OHB’s 3D morphology can increase its receptor-current dynamic range more than twofold. Our findings imply that potential pivot-position changes owing to development, mutations, or location within the mammalian auditory organ might greatly alter OHB function.

Non-linear ground deformation detection and monitoring using time series InSAR along the coastal urban areas of Pakistan.

Conventional geodetic methods rely on point measurements, which have drawbacks for detecting and tracking geologic disasters at specific locations. In this study, the time series Interferometric Synthetic Aperture Radar (InSAR) approach was incorporated to estimate non-linear surface deformation caused by tectonic, shoreline reclamation, and other anthropogenic activities in economically important urban regions of Pakistan's southern coast, which possesses around 270km. The shoreline is extended from the low-populated area on the premises of the Hub River in the west to the highly populated Karachi City and Eastern Industrial Zone, where we collected the Sentinel-1A C-band data from 2017 to 2023 to address urban security and threats to human life and property. The main advantage of opting for the non-linear persistent scatterer interferometric SAR (PSInSAR) approach for this study is that it exposes minute movements without any prior consideration of conventional monitoring techniques, making it valid in continuously varying regions. An average vertical displacement range of - 170 to + 82mm per year was found, which was used to investigate the potential correlation with the most effective causative parameters of deformation. The densely populated areas of the study area experience an annual subsidence of 170mm, and the less populated western region experiences an uplift of 82mm annually. Land deformation varies along the coast of the study area, where the eastern region is highly reclaimed and is affected by erosion. Groundwater table-depleting regions experienced high levels of land subsidence, and tectonic activities controlled vertical displacement in the region. Major variation was detected after an earthquake occurred along fault lines. This study was designed because a non-linear approach is required to address ground movement activities acutely, and it will make it possible to plan surface infrastructure and handle issues brought on by subsidence more effectively.

A study on maglev force and vibration attenuation characteristics of quasi-zero stiffness cruciform maglev isolator.

This paper aims to study the maglev force and vibration attenuation characteristics of quasi-zero stiffness cruciform maglev isolators (CMIs). The maglev force and stiffness of CMIs were analytically computed based on equivalent charge theory, and the transfer function of the system was conducted. The effects of magnet geometry parameters and air gap on the maglev force, stiffness, and vibration transmission characteristics of the CMI system were revealed through parametric analyses. With the increase in magnet length and width, the maximum value of maglev force increases, but the displacement range of near-zero stiffness, amplitude, and phase of the system gradually decrease. With the increase in magnet height, the displacement range of near-zero stiffness increases, while the variation in the amplitude and phase of the system has minimal impact. Meanwhile, in the Halbach array, the height variation of the magnet at different positions has different impacts on the magnetic force. As the air gap increases, the maximum value of maglev force decreases, but the amplitude and phase gradually increase, and the displacement range of near-zero stiffness first rises and then decreases. Finally, an experimental study was carried out to test the vibration attenuation characteristics of CMIs, in which sinusoidal excitation, hammer strike excitation, and random excitation were applied.

Investigation on liquid medium integration for piezoelectric MEMS tunable liquid lenses

In this paper, the design, fabrication and evaluation of a novel piezoelectric MEMS varifocal liquid lens are presented. The device consists of a thin film PZT actuator integrated with a liquid lens, featuring a new design with a modified disk-shaped actuator that enhances the overall displacement range. The primary innovation lies in simplifying the assembly process between the liquid/soft lens and the piezoelectric actuator, eliminating the need for vacuum bonding. Two types of liquid/soft lens materials, ionic gel and silicone oil, were investigated in different integration configurations to find the most suitable method. Analytical calculations and FEM simulations were conducted to optimize the actuator’s maximum displacement, which in turn maximizes the change in the device’s focal length. The developed actuator achieved around 15 µm of static displacement under a 40 V DC applied voltage, which matched well with simulation results. The shifting of the focus was clearly observed through a microscope, with the focal length estimated to change from infinity to about 31.6 mm at 35 V DC.

Kinematic changes in dairy cows with induced hindlimb lameness: transferring methodology from the field of equine biomechanics

Lameness is a common issue on dairy farms, with serious implications for economy and animal welfare. Affected animals may be overlooked until their condition becomes severe. Thus, improved lameness detection methods are needed. In this study, we describe kinematic changes in dairy cows with induced, mild to moderate hindlimb lameness in detail using a “whole-body approach”. Thereby, we aimed to identify explicable features to discriminate between lame and non-lame animals for use in future automated surveillance systems. For this purpose, we induced a mild to moderate and fully reversible hindlimb lameness in 16 dairy cows. We obtained 41 straight-line walk measurements (containing > 3 000 stride cycles) using 11 inertial measurement units attached to predefined locations on the cows’ upper body and limbs. One baseline and ≥ 1 induction measurement(s) were obtained from each cow. Thirty-one spatial and temporal parameters related to limb movement and inter-limb coordination, upper body vertical displacement symmetry and range of motion (ROMz), as well as pelvic pitch and roll, were calculated on a stride-by-stride basis. For upper body locations, vertical within-stride movement asymmetry was investigated both by calculating within-stride differences between local extrema, and by a signal decomposition approach. For each parameter, the baseline condition was compared with induction condition in linear mixed−effect models, while accounting for stride duration. Significant difference between baseline and induction condition was seen for 23 out of 31 kinematic parameters. Lameness induction was associated with decreased maximum protraction (−5.8%) and retraction (−3.7%) angles of the distal portion of the induced/non-induced limb respectively. Diagonal and lateral dissociation of foot placement (ratio of stride duration) involving the non-induced limb decreased by 8.8 and 4.4%, while diagonal dissociation involving the induced limb increased by 7.7%. Increased within-stride vertical displacement asymmetry of the poll, neck, withers, thoracolumbar junction (back) and tubera sacrale (TS) were seen. This was most notable for the back and poll, where a 40 and 24% increase of the first harmonic amplitude (asymmetric component) and 27 and 14% decrease of the second harmonic amplitude (symmetric component) of vertical displacement were seen. ROMz increased in all these landmarks except for TS. Changes in pelvic roll main components, but not in the range of motion of either pitch or roll angle per stride, were seen. Thus, we identified several kinematic features which may be used in future surveillance systems. Further studies are needed to determine their usefulness in realistic conditions, and to implement methods on farms.

3D-ElectroZip touch: multi-directional haptic feedback with electro-ribbon zipping actuators

This paper introduces the 3D-ElectroZip Touch, a multi-directional force feedback device developed using dielectrophoretic liquid zipping actuation. The device is designed to stimulate the sense of normal and shear forces by moving in vertical and multiple horizontal directions. Its performance, including displacement, force, and actuation time has been characterized under input voltages from 6 kV to 9 kV, demonstrating a displacement range of 5–11 mm, force range of 0.05 N to 0.22 N, power output ranges from 0.08 W to 0.077 W, and maximum energy efficiency of 72%. The 3D-ElectroZip Touch shows a quick response to the input signal, moving its contact panel by 1.1 mm in 70 ms (36.5% of human reaction time) at 9 kV. Comparing its basic characteristics with the skin sensitivity and the lightweight, compliance, and scalability of the 3D-ElectroZip Touch technology show its high potential to be exploited in tactile displays and wearable haptic feedback devices.