Collision analysis and safety evaluation using a collision model for the frontal robot–human impact

Robotica ◽  
2014 ◽  
Vol 33 (7) ◽  
pp. 1536-1550 ◽  
Author(s):  
Jung-Jun Park ◽  
Jae-Bok Song ◽  
Sami Haddadin
Keyword(s):  
Impact Analysis ◽  
Safety Evaluation ◽  
Design Parameters ◽  
Body Parts ◽  
Robot Arm ◽  
Collision Model ◽  
Crash Testing ◽  
Mass Spring ◽  
Head Neck ◽  
Significant Attention

SUMMARYThe safety analysis of human–robot collisions has recently drawn significant attention, as robots are increasingly used in human environments. In order to understand the potential injury a robot could cause in case of an impact, such incidents should be evaluated before designing a robot arm based on biomechanical safety criteria. In recent literature, such incidents have been investigated mostly by experimental crash-testing. However, experimental methods are expensive, and the design parameters of the robot arm are difficult to change instantly. In order to solve this issue, we propose a novel robot-human collision model consisting of a 6-degree-of-freedom mass-spring-damper system for impact analysis. Since the proposed robot-human consists of a head, neck, chest, and torso, the relative motion among these body parts can be analyzed. In this study, collision analysis of impacts to the head, neck, and chest at various collision speeds are conducted using the proposed collision model. Then, the degree of injury is estimated by using various biomechanical severity indices. The reliability of the proposed collision model is verified by comparing the obtained simulation results with experimental results from literature. Furthermore, the basic requirements for the design of safer robots are determined.

A Flexible Multibody Model of a Safety Robot Arm for Experimental Validation and Analysis of Design Parameters

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
J. López-Martínez ◽  
D. García-Vallejo ◽  
A. Giménez-Fernández ◽  
J. L. Torres-Moreno
Keyword(s):  
Human Head ◽  
Experimental Results ◽  
Service Robots ◽  
Design Parameters ◽  
Robot Arm ◽  
Safety Requirements ◽  
Multibody Model ◽  
Risk Of Injury ◽  
Link Flexibility ◽  
Head Neck

Service robots must comply with very demanding safety requirements in order to guarantee that a human can be assisted without any risk of injury. This paper presents a detailed multibody model of the interaction between a single link manipulator and a human head–neck to study the different and more significant parameters involved in the design of the manipulator. The multibody model is first validated through comparison with experimental results obtained in a testbed, which has been built for this purpose. The testbed consists of a flexible pendulum with an inertial wheel attached to the pendulum shaft and a head–neck dummy of 1 degree of freedom (DOF). A phenomenological model of the robot-arm foam soft cover has been developed by fitting experimental results obtained in a compressive test performed on the foam. Once the multibody model is qualitatively validated, several simulations are carried out. The aim of the simulations is to study the effect of different design parameters in the head injury. In particular, the effects of the link flexibility, of the joint compliance, and of the soft cover are detailed.

scholarly journals Design of Biomechanical Legs with a Passive Toe Joint for Enhanced Human-like Walking

2017 ◽  
Vol 14 (2) ◽  
pp. 166 ◽  
Author(s):  
Riadh Zaier ◽  
A. Al-Yahmedi
Keyword(s):  
Design Procedure ◽  
Human Walking ◽  
Human Gait ◽  
Design Parameters ◽  
Sultan Qaboos University ◽  
Motion Trajectories ◽  
Normal Human ◽  
Working Principle ◽  
Mass Spring ◽  
Torsion Springs

This paper presents the design procedure of a biomechanical leg, with a passive toe joint, which is capable of mimicking the human walking. This leg has to provide the major features of human gait in the motion trajectories of the hip, knee, ankle, and toe joints. Focus was given to the approach of designing the passive toe joint of the biomechanical leg in its role and effectiveness in performing human like motion. This study was inspired by experimental and theoretical studies in the fields of biomechanics and robotics. Very light materials were mainly used in the design process. Aluminum and carbon fiber parts were selected to design the proposed structure of this biomechanical leg, which is to be manufactured in the Mechanical Lab of the Sultan Qaboos University (SQU). The capabilities of the designed leg to perform the normal human walking are presented. This study provides a noteworthy and unique design for the passive toe joint, represented by a mass-spring damper system, using torsion springs in the foot segment. The working principle and characteristics of the passive toe joint are discussed.  Four-designed cases, with different design parameters, for the passives toe joint system are presented to address the significant role that the passive toe joint plays in human-like motion. The dynamic motion that is used to conduct this comparison was the first stage of the stance motion. The advantages of the presence of the passive toe joint in gait, and its effect on reducing the energy consumption by the other actuated joints are presented and a comparison between the four-designed cases is discussed.

Thermal-Hydraulic Design Support and Safety Analyses of SEALER UK Demo

2020 ◽  
Author(s):  
Kevin Zwijsen ◽  
Heleen Uitslag-Doolaard ◽  
Ferry Roelofs ◽  
Janne Wallenius
Keyword(s):  
Fuel Cycle ◽  
Safety Evaluation ◽  
Evaluation Process ◽  
Design Parameters ◽  
Cfd Model ◽  
Pressure Drops ◽  
Design Values ◽  
Water Reactors ◽  
Passively Safe ◽  
The Uk

Abstract SEALER (SwEdish Advanced Lead Reactor) is a passively safe lead-cooled reactor designed for commercial power production, under design by the LeadCold company. The reactor is modular in design, allowing for factory production and reduction in investment risk compared with new-build of large Light Water Reactors. Furthermore, its core is designed such that it can generate power for up to 25 years without the need of on-site fuel-cycle operations. The SEALER UK model has specifically been designed to produce base-load power on the UK grid. In the design and safety evaluation process, NRG is currently providing support to LeadCold Reactors with respect to thermal-hydraulic safety analyses utilizing Computational Fluid Dynamics (CFD) competences. The current paper gives a comprehensive description of a 3D CFD model created of SEALER UK Demo, which is a scaled-down demonstrator of SEALER UK. The geometry of the CFD model of SEALER UK Demo as well as the modelling approach and numerical settings are presented here. Assumptions were made in order to make it computationally feasible to perform simulations. These are discussed as well. Subsequently, the 3D CFD model is used to perform steady-state analyses of SEALER UK Demo operating under nominal conditions. Main parameters such as mass flow rates, temperatures and core pressure drops coming from the model match the design values well, with differences being at most a couple percent. Also, it is found that the margin to lead freezing with the current design parameters is more than 50K.

scholarly journals Structural Design and Impact Analysis of Deployable Habitat Modules

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Yihong Hong ◽  
Wenjuan Yao ◽  
Yan Xu
Keyword(s):  
Structural Design ◽  
Impact Analysis ◽  
Dynamic Responses ◽  
Design Parameters ◽  
Composite Shells ◽  
Steel Cylinder ◽  
Low Speed ◽  
Fea Model ◽  
Future Space ◽  
Final Design

Space-deployable habitat modules provide artificial habitable environments for astronauts and will be widely used for the construction of future space stations and lunar habitats. A novel structural design concept of space-deployable habitat modules consisting of flexible composite shells and deployable trusses has been proposed. Geometric relationships of deployable trusses based on two types of scissor elements were formulated. Flexible composite shells of space habitat modules were designed, and a nonlinear FEA model using ANSYS software was described. Considering folding efficiencies, stiffness, and strength of the structures, the influences of design parameters were analyzed and the final design scheme of space-deployable habitat modules was determined. After detailing the structural designs, low-speed impact dynamic responses between the structures and a stainless steel cylinder were simulated. The analysis results show that dynamic responses are only significant at the point of low-speed impact. The works will provide technical supports for structural designs and engineering applications of space-deployable habitat modules.

scholarly journals Study on the Confidence and Reliability of the Mean Seismic Probability Risk Model

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Xiao-Lei Wang ◽  
Da-Gang Lu
Keyword(s):  
Seismic Design ◽  
Confidence Level ◽  
Risk Model ◽  
Safety Evaluation ◽  
Design Parameters ◽  
Critical Infrastructures ◽  
High Confidence ◽  
Confidence Levels ◽  
The Mean ◽  
Mean Risk

The mean seismic probability risk model has widely been used in seismic design and safety evaluation of critical infrastructures. In this paper, the confidence levels analysis and error equations derivation of the mean seismic probability risk model are conducted. It has been found that the confidence levels and error values of the mean seismic probability risk model are changed for different sites and that the confidence levels are low and the error values are large for most sites. Meanwhile, the confidence levels of ASCE/SEI 43-05 design parameters are analyzed and the error equation of achieved performance probabilities based on ASCE/SEI 43-05 is also obtained. It is found that the confidence levels for design results obtained using ASCE/SEI 43-05 criteria are not high, which are less than 95%, while the high confidence level of the uniform risk could not be achieved using ASCE/SEI 43-05 criteria and the error values between risk model with target confidence level and mean risk model using ASCE/SEI 43-05 criteria are large for some sites. It is suggested that the seismic risk model considering high confidence levels instead of the mean seismic probability risk model should be used in the future.

scholarly journals Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object

2016 ◽  
Vol 41 (1) ◽  
pp. 119-131 ◽  
Author(s):  
Min-Chie Chiu ◽  
Ying-Chun Chang ◽  
Long-Jyi Yeh ◽  
Chiu-Hung Chung
Keyword(s):  
Optimal Design ◽  
Energy Harvester ◽  
Damping Ratio ◽  
Electrical Power ◽  
Electromagnetic Energy ◽  
Design Parameters ◽  
Helical Springs ◽  
Spring Wire ◽  
Excitation Period ◽  
Mass Spring

Abstract The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (Dm), the magnet height (Hm), the system damping ratio (ζsys), the spring diameter (Ds), the diameter of the spring wire (ds), the spring length (ℓs), the pitch of the spring (ps), the spring’s number of revolutions (Ns), the coil diameter (Dc), the diameter of the coil wire (dc), and the coil’s number of revolutions (Nc). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (Dm, Hm, ζsys, and Nc). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (Dm, Hm, ζsys, and Nc) via the simulated annealing method. Consequently, the optimal design parameters of Dm, Hm, ζsys, and Nc that produce maximum electrical power for an electromagnetic energy harvester are found.

scholarly journals Dimensi Etika, Estetika dan Hukum dalam Ayat-Ayat al-Qur’an tentang Pakaian

2020 ◽  
Vol 16 (1) ◽  
pp. 61-77
Author(s):  
Muh Irfan Helmy
Keyword(s):  
Human Nature ◽  
Main Function ◽  
Body Parts ◽  
Sociological Approach ◽  
Head Neck

In the Qur'an, the Quranic verse about clothing is an important theme which is worth elaborating to reveal the purpose of mentioning it. The urgency of the Quranic verse about clothing is illustrated by the terms which the Qur'an uses when talking about clothing. The Qur'an uses different terms, namely libas, zinah, labus, tsiyab and sarabil, all of which show the meaning of covering and protecting. This article aimed to reveal the dimensions contained in the terms of clothing used by the Qur'an. In addition, this article also aimed to reveal the meaning of the terms of clothing in the context of culture and people's tradition when the Qur'an was descended. Using a thematic method and a historical-sociological approach to the terms of clothing in the Qur'an, this article came to the finding that dressing in principle is commandment of Allah as evidence of His love for humans. The main function of clothing is as a cover of aurat (body parts required by Islam to be covered) reflecting that human having higher degree than other creatures. Human contentment on clothes and jewelry is basically in accordance with human nature. Humans are given freedom to make clothes to fulfill their needs by observing the criteria established by the Sharia. Islam is totally concerned about the ethics of dressing in worship and instructs to wear clean, holy and simple clothing. The Qur'an commands a muslim female believer to cover her head, neck and chest with a hijab so that it cannot be seen by others and is evidence of every muslim female believer in maintaining her honor and dignity. Dalam al-Qur’an tema pakaian termasuk tema penting yang layak dielaborasi untuk mengungkap tujuan dari penyebutan tema pakaian tersebut. Urgensi tema pakaian tergambar dari term-term yang digunakan al-Qur’an ketika berbicara tentang pakaian. Al-Quran menggunakan istilah-istilah yang berbeda, yaitu libas, zinah, labus, tsiyab dan sarabil, yang semuanya menunjukkan kepada arti menutupi dan melindungi. Artikel ini bertujuan untuk mengungkap dimensi-dimensi yang terkandung dalam term-term pakaian yang digunakan al-Qur’an. Disamping itu, artikel ini juga bertujuan untuk mengungkap pemaknaan term-term pakaian tersebut dalam konteks budaya dan tradisi masyarakat saat al-Qur’an diturunkan. Dengan menggunakan metode tematik  dan pendekatan historis-sosiologis  terhadap term-term pakaian dalam al-Qur’an, artikel ini sampai pada temuan bahwa bererpakaian pada prinsipnya adalah perintah Allah sebagai bukti kasih saying-Nya kepada manusia. Fungsi utama dari pakaian adalah sebagai penutup aurat yang mencerminkan ketinggian derajat manusia dibanding makhluk lain. Kecintaan manusia kepada pakaian dan perhiasan pada dasarnya sesuai dengan fitrah manusia. Manusia diberi kebebasan untuk membuat pakaian dalam memenuhi kebutuhannya dengan memperhatikan kriteria yang ditetapkan syariat. Agama Islam sangat memperhatikan etika berpakaian dalam beribadah dan memerintahkan untuk memakai pakaian bersih, suci dan sederhana. Al-Qur’an memerintahkan perempuan mukmin untuk menutup kepala, leher dan dadanya dengan hijab sehingga tidak dapat terlihat oleh orang lain dan menjadi bukti setiap perempuan mukmin dalam menjaga kehormatan dan harga dirinya.

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