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.

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.

scholarly journals Frequency spectrum of the human head–neck to mechanical vibrations

2017 ◽  
Vol 37 (3) ◽  
pp. 611-618 ◽  
Author(s):  
Bin Yang ◽  
Zheng Shi ◽  
Qun Wang ◽  
Feng Xiao ◽  
Tong-Tong Gu ◽  
...  
Keyword(s):  
Finite Element ◽  
Frequency Spectrum ◽  
Mechanical Vibration ◽  
Three Dimensional ◽  
Human Head ◽  
Element Model ◽  
Mode Shapes ◽  
Joint Disorder ◽  
Biomechanical Responses ◽  
Head Neck

This study is based on a real finite element human head–neck model and concentrates on its numerical vibration characteristic. Frequency spectrum and mode shapes of the finite element model of human head–neck under mechanical vibration have been calculated. These vibration characteristics are in good agreement with the previous studies. The simulated fundamental frequency of 35.25 Hz is fairly similar to the published documents, and rarely reported modal responses such as “mastication” and flipping of nasal lateral cartilages modes, however, are introduced by our three-dimensional modal analysis. These additional modes may be of interest to surgeons or clinicians who are specialized in temporomandibular or rhinoplasty joint disorder. Modal validation in terms of modal shapes proposes a necessity for elaborate modeling to identify each individual part’s extra frequencies. Furthermore, it also studies the influence of damping on resonant frequencies and biomechanical responses. It is discovered that damping has an inverse proportionality between damping effect on natural frequency and that on biomechanical responses.

scholarly journals Safe Joint Mechanism using torsion springs for Collision Safety and Positioning Accuracy of a Robot Arm

2020 ◽  
Author(s):  
Adel Belharet ◽  
Jae-Bok Song
Keyword(s):  
Service Robots ◽  
Robot Arm ◽  
Positioning Accuracy ◽  
External Torque ◽  
High Stiffness ◽  
Collision Safety ◽  
Passive Compliance ◽  
Joint Mechanism ◽  
Mechanical Elements ◽  
Torsion Springs

In recent years, the potential for collision between humans and robots has drawn much attention since service robots are increasingly being used in the human environment. A safe robot arm can be achieved using either an active or passive compliance method. A passive compliance system composed of purely mechanical elements often provides faster and more reliable responses to dynamic collision than an active system involving sensors and actuators. Since positioning accuracy and collision safety of a robot arm are equally important, a robot arm should have very low stiffness when subjected to a collision force capable of causing human injury. Otherwise, it should maintain a very high stiffness. To implement these requirements, a novel safe joint mechanism (SJM-IV) consisting of a CAM, rotational links with rollers, and torsion springs is proposed. The SJM-IV has the advantage of nonlinear stiffness, which can be achieved only with passive mechanical elements. Various analyses and experiments on static and dynamic collisions show high stiffness of the SJM-IV against an external torque less than a predetermined threshold torque, with an abrupt drop in stiffness when the external torque exceeds this threshold. The safe joint mechanism enables a robot manipulator to guarantee positioning accuracy and collision safety, and which is simple to install between an actuator and a robot link without a significant change in the robot’s design.

Self-Calibration of Eye-to-Hand and Workspace for Mobile Service Robot

2012 ◽  
pp. 229-246
Author(s):  
Jwu-Sheng Hu ◽  
Yung-Jung Chang
Keyword(s):  
Visual Information ◽  
Calibration Method ◽  
Industrial Robots ◽  
Service Robots ◽  
Service Robot ◽  
Mobile Service ◽  
Robot Arm ◽  
Self Calibration ◽  
Laser Distance Sensor ◽  
Distance Sensor

The geometrical relationships among robot arm, camera, and workspace are important to carry out visual servo tasks. For industrial robots, the relationships are usually fixed and well calibrated by experienced operators. However, for service robots, particularly in mobile applications, the relationships might be changed. For example, when a mobile robot attempts to use the visual information from environmental cameras to perform grasping, it is necessary to know the relationships before taking actions. Moreover, the calibration should be done automatically. This chapter proposes a self-calibration method using a laser distance sensor mounted on the robot arm. The advantage of the method, as compared with pattern-based one, is that the workspace coordinate is also obtained at the same time using the projected laser spot. Further, it is not necessary for the robot arm to enter the view scope of the camera for calibration. This increases the safety when the workspace is unknown initially.

scholarly journals A Cooperative Human-Robot Interface for Constrained Manipulation in Robot-Assisted Endonasal Surgery

2020 ◽  
Vol 10 (14) ◽  
pp. 4809 ◽  
Author(s):  
Jacinto Colan ◽  
Jun Nakanishi ◽  
Tadayoshi Aoyama ◽  
Yasuhisa Hasegawa
Keyword(s):  
Interface Design ◽  
Human Head ◽  
Surgical Instruments ◽  
Invasive Technique ◽  
Robot Arm ◽  
Robot Assisted ◽  
Endonasal Surgery ◽  
Endoscopic Endonasal ◽  
Tool Positioning ◽  
Simultaneous Control

Endoscopic endonasal surgery (EES) is a minimally invasive technique for removal of pituitary adenomas or cysts at the skull base. This approach can reduce the invasiveness and recovery time compared to traditional open surgery techniques. However, it represents challenges to surgeons because of the constrained workspace imposed by the nasal cavity and the lack of dexterity with conventional surgical instruments. While robotic surgical systems have been previously proposed for EES, issues concerned with proper interface design still remain. In this paper, we present a cooperative, compact, and versatile bimanual human-robot interface aimed to provide intuitive and safe operation in robot-assisted EES. The proposed interface is attached to a robot arm and holds a multi-degree-of-freedom (DOF) articulated forceps. In order to design the required functionalities in EES, we consider a simplified surgical task scenario, with four basic instrument operations such as positioning, insertion, manipulation, and extraction. The proposed cooperative strategy is based on the combination of force based robot control for tool positioning, a virtual remote-center-of-motion (VRCM) during insertion/extraction tasks, and the use of a serial-link interface for precise and simultaneous control of the position and the orientation of the forceps tip. Virtual workspace constraints and motion scaling are added to provide safe and smooth control of our robotic surgical system. We evaluate the performance and usability of our system considering reachability, object manipulability, and surgical dexterity in an anatomically realistic human head phantom compared to the use of conventional surgical instruments. The results demonstrate that the proposed system can improve the precision, smoothness and safety of the forceps operation during an EES.

Research of Sewage Marine Discharge Diffusion Effect under Deep Water

2013 ◽  
Vol 726-731 ◽  
pp. 1027-1031
Author(s):  
Hang Yu ◽  
Jing Feng Bai ◽  
Xin Hai Wang ◽  
Hong Xin Zhao
Keyword(s):  
Model Test ◽  
Deep Water ◽  
Near Field ◽  
Large Angle ◽  
Hydraulic Model ◽  
Experimental Results ◽  
Premature Convergence ◽  
Design Parameters ◽  
Diffusion Effect ◽  
Horizontal Angle

The sewage diffusion effect under deep water was carried out between different diffuser design parameters based on the hydraulic model test, and Huizhou Dayawan sewage marine disposal project was taken as an example. The experimental results show that the design parameters are significant for sewage diffusion at the near field. For Dayawan project, jet angle was controlled to be 20 degree, and horizontal angle was controlled to be 90 degree. It not only can ensure that sewage fully diluted mixed, also can avoid the premature convergence and sewage lifting. It is feasible for selecting large angle nozzle under deep water and there are some technical bases have been provided for other sewage marine disposal project.

scholarly journals Hydraulic optimization of corrugated stilling basin with adverse slope

2018 ◽  
Vol 19 (1) ◽  
pp. 313-322 ◽  
Author(s):  
Tooraj Honar ◽  
Nafiseh Khoramshokooh ◽  
Mohammad Reza Nikoo
Keyword(s):  
Optimization Model ◽  
Hydraulic Jump ◽  
Experimental Results ◽  
Data Driven ◽  
Design Parameters ◽  
Algorithm Optimization ◽  
Stilling Basin ◽  
Design Variables ◽  
Bed Slope ◽  
Mlp Model

Abstract In this paper, perhaps for the first time, a data-driven simulation–optimization model is developed based on experimental results to find the effects of state and decision variables on the optimum characteristics of a stilling basin with adverse slope and corrugated bed. The optimal design parameters of the stilling basin are investigated to minimize the length of the hydraulic jump and ratio of the sequent depths of the jump while the relative amount of energy loss is maximized. In order to model the relationship between design variables of the bed, the experimental results are converted to a data-driven simulation model on the basis of a multilayer perceptron (MLP) neural network. Then, the validated MLP model is used in a genetic algorithm optimization model in order to determine the optimum characteristics of the bed under the hydraulic jump considering the interaction between the bed design variables and the hydraulic parameters of the flow. Results indicate that the optimum values of bed slope and the diameter of the corrugated roughness (2r) can be considered as −0.02 and 20 millimetres, respectively.

Abstract 3672: Semaphorin 4D in human head & neck cancer: A promising predictive biomarker for the peri-tumoral stromal phenotype

2017 ◽  
Author(s):  
Rania H. Younis ◽  
Roshanak Derakhshandeh ◽  
Ahmed Sultan ◽  
Haiyan Chen ◽  
Kyu Lee Han ◽  
...  
Keyword(s):  
Neck Cancer ◽  
Human Head ◽  
Predictive Biomarker ◽  
Head Neck Cancer ◽  
Semaphorin 4D ◽  
Head Neck

scholarly journals Hand-Arm Vibration Assessment and Changes in the Thermal Map of the Skin in Tennis Athletes during the Service

2019 ◽  
Vol 16 (24) ◽  
pp. 5117 ◽  
Author(s):  
Ana M. Amaro ◽  
Maria F. Paulino ◽  
Maria A. Neto ◽  
Luis Roseiro
Keyword(s):  
Infrared Thermography ◽  
Tennis Elbow ◽  
Health And Safety ◽  
Lateral Epicondylitis ◽  
Biomechanical Analysis ◽  
Tennis Players ◽  
Safety Requirements ◽  
European Directive ◽  
Risk Of Injury ◽  
Different Types

During recent years the number of tennis athletes has increased significantly. When playing tennis, the human body is exposed to many situations which can lead to human injuries, such as the so-called tennis elbow (lateral epicondylitis). In this work a biomechanical analysis of tennis athletes, particularly during the service, was performed, considering three different types of over-grip and the presence of one anti-vibrator device. One part of the study evaluates the exposure to hand-arm vibration of the athlete, based on the European Directive 2002/44/EC concerning the minimum health and safety requirements, regarding the exposure of workers to risks from physical agents. The second part of the study considers an infrared thermography analysis in order to identify signs of risk of injury, particularly tennis elbow, one of the most common injuries in this sport. The results show that the presence of the anti-vibrator influences the vibration values greatly in the case of athletes with more experience and also for athletes with less performance. The presence of the Cork and/or Tourna on the racket grip does not have any significant effect on the hand-arm vibration (HAV), similarly in the case of athletes with the best performance and athletes with less technique. The results indicated that the infrared thermography technique may be used to identify the risk of injuries in tennis players.

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