scholarly journals Decision synthesis in engineering design of technological attachment

Author(s):  
D. P. Kunkevich ◽  
I. L. Kovaleva ◽  
A. A. Baryshau

Synthesis of the engineering design decisions is considered. The fixtures for locating and clamping parts to be tooled at the manufacturing operations are the design objects. An approach to topology and parametric design are proposed. Most efficiently these tasks are solved at the function level. Finally, geometry models and design drawings are needed for manufacturing. Fixture action is to mate bases of fixture object with function faces of fixture locators. This is constraining the degrees of freedom of object. Every base constrains certain degree of freedom. In accordance with quantity and quality of that degrees, certain locators are appointed to the base and them must be positioned resulting in the a locating chart. The quality of the locating chart may be evaluated by the several criteria, for example, by it dimensions. Unsatisfactory solution may be followed by redistributing degrees of freedom among the bases or editing positions of locators within the bases. Thus the design is decomposed onto two independent tasks of different levels.

Author(s):  
D. C. Simpson

The arm which is being developed at the Princess Margaret Rose Orthopaedic Hospital, Edinburgh, has voluntary control of four degrees of freedom of the hand (three positional and one rotational), prehension, automatic control of a further degree of freedom (rotational), and can provide an indication of ‘feel’. The control and use of a multimovement arm such as this would present an unacceptably severe task if it was attempted on a time/velocity basis. Over the last two and a half years we have been fitting a position-servo system to our present simple arm (two movements and prehension) and the children who use it have achieved a considerable degree of unconscious control and position awareness of the limb. The results that have been achieved with position-servo control of the present arm have depended on using the proprioceptive information which has been provided by the shoulder control sites as a reflection of the positional state of the limb, and they demonstrate the quality of the match of the characteristics of the arm to those of the user.


2021 ◽  
Vol 101 ◽  
pp. 03026
Author(s):  
Nadezda Bagdasaryan ◽  
Raisa Petruneva ◽  
Valentina Vasilyeva ◽  
Olga Toporkova

A theoretical and methodological analysis of the content characteristics of engineering education correlated with the challenges of the fourth industrial revolution (Industry 4.0) showed that trends of the third technological revolution dominate in the current university engineers' training model. One of the effective tools for the formation of a university model for training an engineer of the future could be the ideas of using educational social engineering problems based on elements of socio-humanitarian expertise of engineering design decisions. An optimally designed model of an engineer of the future will improve the quality of training and, ultimately, avoid the negative (fatal) consequences of insufficiently substantiated engineering design decisions.


Author(s):  
P E Simmons

In this paper the author has attempted to show how the quality of some engineering design decisions can be improved by the use of reliability engineering and other statistical techniques.


Author(s):  
Muhammad Faizan Shah ◽  
Zareena Kausar ◽  
Muhammad Umer Farooq ◽  
Liaquat Ali Khan ◽  
Syed Saad Farooq

Machining is material removal from a workpiece. Current spindle technologies allow the material to be removed very quickly but unfortunately this compromises the accuracy of the desired machined trajectory on the workpiece. Proposed solution to the problem is restricting motion of the tool and giving rotation to the workpiece. This paper presents analysis of the accuracy of trajectory of material removal from a workpiece, such that the workpiece rotates with six degrees of freedom, in the presence of error generated due to an offset of the workpiece from centre of the moving platform of the machining bed. The kinematics of the machining bed is, therefore, modeled using as inverse kinematic formulation applying geometric and vector addition method. The mechanism outputs three rotational and three translational motions. The leg length for each of six legs of the bed is computed individually. Moreover, workpiece position offset error is modelled to find actual leg lengths of the bed. Finally accuracy computation model is proposed to analyse the accuracy of the final trajectory of the motion of the workpiece. The models are verified in simulation for a trajectory and validated experimentally on a six degree of freedom (6DOF) machining bed. The results reveal maximum inaccuracy in machining trajectory to be 1% in experiments while less than 1% in simulation. This verifies quality of the mechanism and efficacy of the proposed 6DOF machining bed in machining accuracy.


Author(s):  
Yudong Qiu ◽  
Daniel Smith ◽  
Chaya Stern ◽  
mudong feng ◽  
Lee-Ping Wang

<div>The parameterization of torsional / dihedral angle potential energy terms is a crucial part of developing molecular mechanics force fields.</div><div>Quantum mechanical (QM) methods are often used to provide samples of the potential energy surface (PES) for fitting the empirical parameters in these force field terms.</div><div>To ensure that the sampled molecular configurations are thermodynamically feasible, constrained QM geometry optimizations are typically carried out, which relax the orthogonal degrees of freedom while fixing the target torsion angle(s) on a grid of values.</div><div>However, the quality of results and computational cost are affected by various factors on a non-trivial PES, such as dependence on the chosen scan direction and the lack of efficient approaches to integrate results started from multiple initial guesses.</div><div>In this paper we propose a systematic and versatile workflow called \textit{TorsionDrive} to generate energy-minimized structures on a grid of torsion constraints by means of a recursive wavefront propagation algorithm, which resolves the deficiencies of conventional scanning approaches and generates higher quality QM data for force field development.</div><div>The capabilities of our method are presented for multi-dimensional scans and multiple initial guess structures, and an integration with the MolSSI QCArchive distributed computing ecosystem is described.</div><div>The method is implemented in an open-source software package that is compatible with many QM software packages and energy minimization codes.</div>


2012 ◽  
Vol 6 (1) ◽  
pp. 5-15 ◽  
Author(s):  
Michael R Dawson ◽  
Farbod Fahimi ◽  
Jason P Carey

The objective of above-elbow myoelectric prostheses is to reestablish the functionality of missing limbs and increase the quality of life of amputees. By using electromyography (EMG) electrodes attached to the surface of the skin, amputees are able to control motors in myoelectric prostheses by voluntarily contracting the muscles of their residual limb. This work describes the development of an inexpensive myoelectric training tool (MTT) designed to help upper limb amputees learn how to use myoelectric technology in advance of receiving their actual myoelectric prosthesis. The training tool consists of a physical and simulated robotic arm, signal acquisition hardware, controller software, and a graphical user interface. The MTT improves over earlier training systems by allowing a targeted muscle reinnervation (TMR) patient to control up to two degrees of freedom simultaneously. The training tool has also been designed to function as a research prototype for novel myoelectric controllers. A preliminary experiment was performed in order to evaluate the effectiveness of the MTT as a learning tool and to identify any issues with the system. Five able-bodied participants performed a motor-learning task using the EMG controlled robotic arm with the goal of moving five balls from one box to another as quickly as possible. The results indicate that the subjects improved their skill in myoelectric control over the course of the trials. A usability survey was administered to the subjects after their trials. Results from the survey showed that the shoulder degree of freedom was the most difficult to control.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.


2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed Obaid ◽  
Qianwei Zhang ◽  
Scott J. Adams ◽  
Reza Fotouhi ◽  
Haron Obaid

Abstract Background Telesonography systems have been developed to overcome barriers to accessing diagnostic ultrasound for patients in rural and remote communities. However, most previous telesonography systems have been designed for performing only abdominal and obstetrical exams. In this paper, we describe the development and assessment of a musculoskeletal (MSK) telesonography system. Methods We developed a 4-degrees-of-freedom (DOF) robot to manipulate an ultrasound probe. The robot was remotely controlled by a radiologist operating a joystick at the master site. The telesonography system was used to scan participants’ forearms, and all participants were conventionally scanned for comparison. Participants and radiologists were surveyed regarding their experience. Images from both scanning methods were independently assessed by an MSK radiologist. Results All ten ultrasound exams were successfully performed using our developed MSK telesonography system, with no significant delay in movement. The duration (mean ± standard deviation) of telerobotic and conventional exams was 4.6 ± 0.9 and 1.4 ± 0.5 min, respectively (p = 0.039). An MSK radiologist rated quality of real-time ultrasound images transmitted over an internet connection as “very good” for all telesonography exams, and participants rated communication with the radiologist as “very good” or “good” for all exams. Visualisation of anatomic structures was similar between telerobotic and conventional methods, with no statistically significant differences. Conclusions The MSK telesonography system developed in this study is feasible for performing soft tissue ultrasound exams. The advancement of this system may allow MSK ultrasound exams to be performed over long distances, increasing access to ultrasound for patients in rural and remote communities.


2021 ◽  
Vol 11 (5) ◽  
pp. 2153
Author(s):  
Nadia Giuffrida ◽  
Maja Stojaković ◽  
Elen Twrdy ◽  
Matteo Ignaccolo

Container terminals are the main hubs of the global supply chain but, conversely, they play an important role in energy consumption, environmental pollution and even climate change due to carbon emissions. Assessing the environmental impact of this type of port terminal and choosing appropriate mitigation measures is essential to pursue the goals related to a clean environment and ensuring a good quality of life of the inhabitants of port cities. In this paper the authors present a Terminal Decision Support Tool (TDST) for the development of a container terminal that considers both operation efficiency and environmental impacts. The TDST provides environmental impact mitigation measures based on different levels of evolution of the port’s container traffic. An application of the TDST is conducted on the Port of Augusta (Italy), a port that is planning infrastructural interventions in coming years in order to gain a new role as a reference point for container traffic in the Mediterranean.


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