General evaluation method of safety for human-care robots

Author(s):  
K. Ikuta ◽  
M. Nokata
2000 ◽  
Author(s):  
Koji Ikuta ◽  
Makoto Nokata ◽  
Hideki Ishii

Abstract In this paper, the first danger-evaluation method for use in various kinds of control strategies for human-care robots is proposed. In the case of a careless collision between a robot and a human, impact force and impact stress are chosen as evaluation values, and a danger index is defined to quantitatively evaluate the effectiveness of each safety strategy used for control. As in the previous paper on safety design, this proposed method allows us to assess the contribution of each safety control strategy to the overall safety performance of a human-care robot. In addition, a new type of robot simulation system for danger-evaluation is constructed on a workstation. The system simplifies the evaluation of danger in both the design and control of human-care robots to quantify the effectiveness of various safety strategies. Here we describe the results obtained, the successful optimization of a safety control strategy for human-care robots.


A design method is described for the steadily loaded, full journal bearing. This is presented as a non-iterative set of algebraic equations, where a dependent bearing parameter, e. g. eccentricity or power-loss, is predicted in terms of known independent parameters which include bearing geometry, running conditions and oil characteristics. The method is developed from a regression analysis of accurately computed, fully thermohydrodynamic, solutions for the bearing. These solutions are generated by simultaneously solving the Reynolds and energy equations in the oil film, the Laplace equation in the bearing material and the oil-mixing conditions at inlet. A quasi three-dimensional finite-difference technique is used. Both the particular solutions and the predictions of the design method compare favourably with a wide range of experimental data, the latter showing an improvement in accuracy and economy on existing design methods.


2020 ◽  
Vol 22 (3) ◽  
pp. 247-256
Author(s):  
Lina Van Aerschot ◽  
Jaana Parviainen

Abstract Twenty-five years ago, robotics guru Joseph Engelberger had a mission to motivate research teams all over the world to design the ‘Elderly Care Giver’, a multitasking personal robot assistant for everyday care needs in old age. In this article, we discuss how this vision of omnipotent care robots has influenced the design strategies of care robotics, the development of R&D initiatives and ethics research on use of care robots. Despite the expectations of robots revolutionizing care of older people, the role of robots in human care has remained marginal. The value of world trade in service robots, including care robots, is rather small. We argue that the implementation of robots in care is not primarily due to negative user attitudes or ethical problems, but to problems in R&D and manufacturing. The care robots currently available on the market are capable of simple, repetitive tasks or colloquial interaction. Thus far, also research on care robots is mostly conducted using imaginary scenarios or small-scale tests built up for research purposes. To develop useful and affordable robot solutions that are ethically, socially and ecologically sustainable, we suggest that robot initiatives should be evaluated within the framework of care ecosystems. This implies that attention has to be paid to the social, emotional and practical contexts in which care is given and received. Also, the political, economic and ecological realities of organizing care and producing technological commodities have to be acknowledged. It is time to openly discuss the drivers behind care robot initiatives to outline the bigger picture of organizing care under conditions of limited resources.


2021 ◽  
Author(s):  
Hai Wang ◽  
Xiaowen Qi ◽  
Yu Dong ◽  
Bingli Fan ◽  
Changxin Liu ◽  
...  

Abstract Polytetrafluoroethylene (PTFE), as one of the most widely used solid lubricating materials, is thought to be very efficient at forming transfer film because of terrific low intermolecular force. This work investigates the tribological properties of PTFE transfer film under dry friction, and further explores its formation process and evolution mechanism. The friction coefficient is the lowest when the transfer film thickness is in range of 8-12 μm. An evaluation method for transfer film is proposed. The results show that the quality of the transfer film is closely related to the test load and velocity. This method is expected to be a general evaluation method for polymer transfer film, which can further directly evaluate the wear state of polymers, and even directly predict the tribological properties of polymers and abrasion life.


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