Search Results (5)

A micro-tiller vibrates severely during the rotary tillage process, which may cause operators to develop white finger disease. However, for most vibration models, the acting force between the soil and the rotary cutter roll was simplified to only a constant or sine curve, which may not describe the whole dynamic. Rotary tillage processes have been simulated based on the smoothed particle hydrodynamics method in this paper. The acting forces of the soil on the cutter roll have been obtained with the simulation model. Four different working conditions were simulated. The average error between the calculated forces and the simulated mean forces is 10.96%, which proves the SPH model. By introducing simulated acting forces into the vibration model, a new vibration model of the micro-tiller, which includes the soil–blade interaction, has been constructed. Time and frequency characteristics were simulated with the new vibration model. The errors between the simulated and tested RMS values are 4.28%, 5.03%, and 6.35% for the engine, cutter roll, and right handle, respectively. Two domain-dominant frequencies were found with the vibration model, namely 44.7 Hz and 257.0 Hz. It is helpful to reveal the whole dynamic map of micro-tillers. Full article

Refractories exposed to corrosive melts at high temperatures experience wear due to dissolution. The presented work deals with the dynamic corrosion of magnesia fine ceramics in a CaO–Al₂O₃–SiO₂–MgO silicate slag with a CaO/SiO₂ weight ratio of 0.65. Finger tests at 200 rpm at three different temperatures, 1450, 1500, and 1550 °C, were performed. A contemporary rotary finger test (RFT) device with in-situ wear profile measurement using a laser device was used. The precise dimension measurements with high-resolution facilitate the determination of total mass flux densities, which allow for determination of effective binary diffusivities. Thereby, two methods based on Sherwood relations were applied. The comparison shows the benefit to better consider deviations from pure cylinder shape. The use of contemporary RFT devices and magnesia fine ceramics allows reliable determination of the effective binary diffusivity. Full article

This paper presents the development of a new microgripper actuated by means of rotary-comb drives equipped with two cooperating fingers arrays. The microsystem presents eight CSFH flexures (Conjugate Surface Flexure Hinge) that allow the designer to assign a prescribed motion to the gripping tips. In fact, the adoption of multiple CSFHs gives rise to the possibility of embedding quite a complex mechanical structure and, therefore, increasing the number of design parameters. For the case under study, a double four-bar linkage in a mirroring configuration was adopted. The presented microgripper has been fabricated by using a hard metal mask on a Silicon-on-Insulator (SOI) wafer, subject to DRIE (Deep Reactive Ion Etching) process, with a vapor releasing final stage. Some prototypes have been obtained and then tested in a lab. Finally, the experimental results have been used in order to assess simulation tools that can be used to minimize the amount of expensive equipment in operational environments. Full article

Recent advancements in telecommunications and the tactile Internet have paved the way for studying human senses through haptic technology. Haptic technology enables tactile sensations and control using virtual reality (VR) over a network. Researchers are developing various haptic devices to allow for real-time tactile sensation, which can be used in various industries, telesurgery, and other mission-critical operations. One of the main criteria of such devices is extremely low latency, as low as 1 ms. Although researchers are attempting to develop haptic devices with low latency, there remains a need to improve latency and robustness to hand sizes. In this paper, a low-latency haptic open glove (LLHOG) based on a rotary position sensor and min-max scaling (MMS) filter is proposed to realize immersive VR interaction. The proposed device detects finger flexion/extension and adduction/abduction motions using two position sensors located in the metacarpophalangeal (MCP) joint. The sensor data are processed using an MMS filter to enable low latency and ensure high accuracy. Moreover, the MMS filter is used to process object handling control data to enable hand motion-tracking. Its performance is evaluated in terms of accuracy, latency, and robustness to finger length variations. We achieved a very low processing delay of 145.37 μs per finger and overall hand motion-tracking latency of 4 ms. Moreover, we tested the proposed glove with 10 subjects and achieved an average mean absolute error (MAE) of ${3.091}^{\circ }$ for flexion/extension, and ${2.068}^{\circ }$ for adduction/abduction. The proposed method is therefore superior to the existing methods in terms of the above factors for immersive VR interaction. Full article

Capturing hand motions for hand function evaluations is essential in the medical field. For many allied health professionals, measuring joint range of motion (ROM) is an important skill. While the universal goniometer (UG) is the most used clinical tool for measuring joint ROM, developments in current sensor technology are providing clinicians with more measurement possibilities than ever. For rehabilitation and manual dexterity evaluations, different data gloves have been developed. However, the reliability and validity of sensor technologies when used within a smart device remain somewhat unclear. This study proposes a novel electronically controlled sensor monitoring system (ECSMS) to obtain the static and dynamic parameters of various sensor technologies for both data gloves and individual sensor evaluation. Similarly, the ECSMS was designed to closely mimic a human finger joint, to have total control over the joint, and to have an exceptionally high precision. In addition, the ECSMS device can closely mimic the movements of the finger from hyperextension to a maximum ROM beyond any person’s finger joint. Due to the modular design, the ECSMS’s sensor monitoring board is independent and extensible to include various technologies for examination. Additionally, by putting these sensory devices through multiple tests, the system accurately measures the characteristics of any rotary/linear sensor in and out of a glove. Moreover, the ECSMS tracks the movement of all types of sensors with respect to the angle values of finger joints. In order to demonstrate the effectiveness of sensory devices, the ECSMS was first validated against a recognised secondary device with an accuracy and resolution of 0.1°. Once validated, the system simultaneously determines real angles alongside the hand monitoring device or sensor. Due to its unique design, the system is independent of the gloves/sensors that were tested and can be used as a gold standard to realise more medical equipment/applications in the future. Consequently, this design greatly enhances testing measures within research contact and even non-contact systems. In conclusion, the ECSMS will benefit in the design of data glove technologies in the future because it provides crucial evidence of sensor characteristics. Similarly, this design greatly enhances the stability and maintainability of sensor assessments by eliminating unwanted errors. These findings provide ample evidence for clinicians to support the use of sensory devices that can calculate joint motion in place of goniometers. Full article