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2021 ◽  
Vol 11 (23) ◽  
pp. 11280
Author(s):  
Yun-Peng Su ◽  
Xiao-Qi Chen ◽  
Tony Zhou ◽  
Christopher Pretty ◽  
J. Geoffrey Chase

This paper presents an integrated scheme based on a mixed reality (MR) and haptic feedback approach for intuitive and immersive teleoperation of robotic welding systems. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time visual feedback from the robot working space. The proposed robotic tele-welding system features imitative motion mapping from the user’s hand movements to the welding robot motions, and it enables the spatial velocity-based control of the robot tool center point (TCP). The proposed mixed reality virtual fixture (MRVF) integration approach implements hybrid haptic constraints to guide the operator’s hand movements following the conical guidance to effectively align the welding torch for welding and constrain the welding operation within a collision-free area. Onsite welding and tele-welding experiments identify the operational differences between professional and unskilled welders and demonstrate the effectiveness of the proposed MRVF tele-welding framework for novice welders. The MRVF-integrated visual/haptic tele-welding scheme reduced the torch alignment times by 56% and 60% compared to the MRnoVF and baseline cases, with minimized cognitive workload and optimal usability. The MRVF scheme effectively stabilized welders’ hand movements and eliminated undesirable collisions while generating smooth welds.


Author(s):  
V. Ya. Dzyuzer

A comprehensive analysis of the quality parameters of fused-cast aluminum-zirconium-silicate (AZS) refractories for glass furnaces has been carried out. It is shown that the assessment of the quality of AZS refractories by the content of ZrO2 and density in them does not give an objective idea of their operational properties. Of fundamental importance are the chemical composition and behavior of the glass phase, which determine the volume and temperature of the onset of exudation. Among the most important conditions for obtaining high-quality AZS refractories, characterized by a melting volume of 2‒3 % of the glass phase and a melting start temperature above 1400 °C, include the oxidative melting technology and the content of impurities in the chemical composition of the refractory no more than 0,25‒0,30 %. The conditions for the service of AZS refractories in the melting basin and the working space of glass-melting furnaces are formulated. Their influence on the course of the exudation process, the corrosion resistance of refractories and the formation of defects in glass is shown. Ill. 2. Ref. 30. Tab. 4.


2021 ◽  

Successful bronchoscopic bronchopleural fistula closure requires both accurate localization of the fistula and device implantation; placing a silicone plug requires experience and skill because of the limited endobronchial working space. We report a novel bronchoscopic silicone plug placement technique for a bronchopleural fistula that developed after a left upper lobectomy following induction chemoradiation therapy, which was then successfully treated by omentopexy.


2021 ◽  
Vol 8 ◽  
Author(s):  
Gilles Decroly ◽  
Pierre Lambert ◽  
Alain Delchambre

The rise of soft robotics opens new opportunities in endoscopy and minimally invasive surgery. Pneumatic catheters offer a promising alternative to conventional steerable catheters for safe navigation through the natural pathways without tissue injury. In this work, we present an optimized 6 mm diameter two-degree-of-freedom pneumatic actuator, able to bend in every direction and incorporating a 1 mm working channel. A versatile vacuum centrifugal overmolding method capable of producing small geometries with a variety of silicones is described, and meter-long actuators are extruded industrially. An improved method for fiber reinforcement is also presented. The actuator achieves bending more than 180° and curvatures of up to 0.1 mm−1. The exerted force remains below 100 mN, and with no rigid parts in the design, it limits the risks of damage on surrounding tissues. The response time of the actuator is below 300 ms and therefore not limited for medical applications. The working space and multi-channel actuation are also experimentally characterized. The focus is on the study of the influence of material stiffness on mechanical performances. As a rule, the softer the material, the better the energy conversion, and the stiffer the material, the larger the force developed at a given curvature. Based on the actuator, a 90 cm long steerable catheter demonstrator carrying an optical fiber is developed, and its potential for endoscopy is demonstrated in a bronchial tree phantom. In conclusion, this work contributes to the development of a toolbox of soft robotic solutions for MIS and endoscopic applications, by validating and characterizing a promising design, describing versatile and scalable fabrication methods, allowing for a better understanding of the influence of material stiffness on the actuator capabilities, and demonstrating the usability of the solution in a potential use-case.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiao-Liang Zhang ◽  
Juchao Liu ◽  
Jiamei Nie ◽  
Hao Wei ◽  
Long Chen

To address the problems of mechanical two-stage inerter-spring-damper (ISD) suspension such as excessive suspension elements, complex structure, and problematic engineering implementation, a hydro-pneumatic two-stage ISD suspension, which integrates hydro-pneumatic spring and inerter, is proposed. The full vehicle model of hydro-pneumatic ISD suspension is established based on the AMESim. Simulation analysis is performed to demonstrate the effectiveness and performances of the proposed suspension. The hydro-pneumatic ISD suspension prototype is developed and tested on four-poster tire-coupled road simulator. The results suggest that, compared with single-chamber hydro-pneumatic suspension, the hydro-pneumatic ISD one can significantly reduce the vibrations of the vehicle body and wheels, but at the expense of an excessive increase of suspension working space (SWS). In contrast, although proposed suspension is also a type of dual-chamber hydro-pneumatic one, it can not only reduce these vibrations but also downsize the SWS, which means it is the best choice for a more comfortable and safer ride.


2021 ◽  
Vol 2093 (1) ◽  
pp. 012007
Author(s):  
JiaLei Su

Abstract The force supple control method of robotic arm has been widely researched internationally for many years, and its specific use varies according to the structure of the robotic arm, the location of the sensor, the working space environment, and other factors. Based on the force control principle and control method of the space robot arm, this paper adopts the position-based Cartesian spatial impedance control and proposes an effective forcesmoothing control method after pre-processing the feedback signal of the six-dimensional force sensor installed at the end of the space robot arm with the coordinate system conversion. In addition, the proposed position-based Cartesian spatial impedance control method is modeled and simulated to analyze the effect of each control element on the force-following control effect, to find out the control conditions that can optimize the force-position control effect, and finally to optimize the impedance parameters. This study aims to promote the rapid development of the field of robotic arm control.


2021 ◽  
Vol 2096 (1) ◽  
pp. 012086
Author(s):  
O V Darintsev ◽  
A B Migranov

Abstract The use of the Hopfield neural network for the task distribution problem solving in teams of mobile robots performing monosyllabic operations in a single workspace is considered. The study is a continuation of earlier works in which the same problem was solved by the authors using other heuristic algorithms – swarm and genetic. This article presents the problem statement and the model of the working space, distinguishes the goals of robotic operation. The quality indicator is the total distance traveled by each of the robots in the group. To enable the original problem to be solved using the Hopfield neural network, a graph representation of the Hopfield is made by switching from the VRP to the TSP problem. The results of computational experiments confirming the effectiveness of the chosen approach for choosing a strategy of behavior of a group of mobile robots are shown.


2021 ◽  
Vol 1199 (1) ◽  
pp. 012093
Author(s):  
N Artyukhova ◽  
J Krmela ◽  
V Krmelová ◽  
A Artyukhov

Abstract The article is devoted to the study of multistage dryers with vertical sectioning of the working space. The factors of influence of the design of the shelf contact and the consumption of the drying agent on the mode of movement of monodisperse and polydisperse material are analyzed. The achievement of the required hydrodynamic regime (at a constant consumption of the drying agent) was ensured by changing the length of the shelf contact, the angle of its inclination to the horizon, and the degree of perforation (free area of cross-section). The features of changing the mode of granular material movement at various stages of the gravitational shelf dryer are shown. A technique for the optimization calculation of a gravitational shelf dryer is proposed. As an objective function, the minimum residence time of the dispersed material in the dryer is taken, at which the required amount of moisture is removed. Variants of the designs of the stages of a gravitational shelf dryer are shown and the features of the movement of dispersed material on the steps are described. The results obtained can be used as the basis for the engineering design of gravitational shelf dryers.


2021 ◽  
Vol 5 (5 (113)) ◽  
pp. 62-79
Author(s):  
Oleksii Korzhyk ◽  
Sergey Naida ◽  
Tetiana Zheliaskova ◽  
Oleksander Chaika ◽  
Nikita Naida

The paper considers the features of the formation of an acoustic field by a spherical source with complicated properties in a regular plane-parallel waveguide, which is of practical importance in marine instrumentation and oceanographic research. The calculation algorithm is based on the use of the Helmholtz equation and the Fourier method for each partial region and the conjugation conditions on their boundaries. The presented calculation allows one to get rid of the idealized boundary conditions on the source surface, with the subsequent determination of the excitation coefficients of the waveguide modes within the framework of the Sturm-Liouville problem. In this case, the attraction of the boundary conditions on the surface and the bottom of the sea, as well as the Sommerfeld conditions, makes it possible to obtain the real distribution of the field in the vertical sections of the waveguide. The obtained frequency dependences of the pressure and vibrational velocity components show their amplitude-phase differences, which reach 90 degrees, which partially explains the appearance of singular points in the intensity field in a regular waveguide. It has been determined that multiple reflections of sound waves from the boundaries of the working space and the space of the waveguide cause oscillations of the pressure components with a change in the amplitude level up to 6 dB. It was found that with an increase in the size of the source, a kind of resonance is formed in the working space, the frequency of which depends on the depth of the sea and corresponds to the region kr=x=5.8. It was found that when the acoustic field is formed in the working space, the frequency response of the impedance components is represented as a multiresonant dependence formed on the basis of the frequency characteristics of the lower modes and their combinations. Experimental studies have shown that the results of calculations of the mode composition of the acoustic field of the emitter, obtained in the conditions of the pool, correspond to the spatial characteristics of the mode components of the acoustic field with an error of up to 3 dB


Author(s):  
Jyoti Doley ◽  
Meenakshi Dey

The recent changes in work environment owing to the COVID 19 pandemic has made us rethink the utility of office space at a time when an exponential growth in the use of online platforms has been observed. With the flexibility of working space and timing, employees and the organizational heads have redefined work culture and the old adage of strict 9 to 5 job seems to have been completed changed. The current paper attempts to understand the four behavioral patterns of DISC exhibited by leaders in any work environment. It explains what are the four behavioral traits and how they influence communication. And in a hybrid work environment, with lot of flexibility in time and space, what steps are to be taken in order to make communication effective and avert miscommunication as half of the employees work offline while the other half works online.


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