An evaluation of machine guarding techniques for robot guarding
Abstract An increasing number of problems caused by the use of industrial robots should be expected due to the dramatically increasing population of robots today. In this paper, machine guarding functions and techniques are reviewed. The possibilities of transferring the concepts of machine guarding to robotic systems are then analyzed. The analysis shows that most of the guarding techniques are still applicable to industrial robots with modifications to accommodate differences. A set of guidelines for installing safeguarding devices is also presented. Research is need in the areas of guarding techniques for robotic cells, new sensor development, and sensor reliability, fusion, and coordination problems.
A cause-and-effect analysis of robot accidents
Abstract Jiang, B.C. and Gainer, C.A., Jr., 1987. A cause-and-effect analysis of robot accidents. Journal of Occupational Accidents , 9: 27–45. Reported cases of robot accidents involving fatality, injury and non-injury were gathered from several sources (U.S., West Germany, Sweden and Japan). In cases where adequate information was available a cause-effect analysis of these accidents was performed. A total of 32 accidents were analyzed in the study. The accident effects were grouped according to who was injured (line worker, maintenance worker or programmer), the type of injury (pinch-point, impact or other), and the degree of injury (fatal, non-fatal-lost-work or non-fatal-no-lost-work). The accident causes were grouped into four categories (human error, workplace design, robot design and other) with the possibility that an accident could have more than one cause. Findings indicate that line workers are at greatest risk, followed by maintenance workers and programmers. Pinch-point accidents accounted for 56% of all accidents while impact accidents accounted for 44%. Most accidents were caused by poor workplace design (20 of 32 accidents) and human error (13 of 32 accidents). A comprehensive cause-effect analysis was performed on 25 of the accidents and includes: the accident source, the accident cause, the accident effect in terms of human injury, recommended guidelines to be implemented, and applicable safety standards in each case. Conclusions are drawn on the effectiveness of worker safety training and workplace design, both a result of suggested standards.
In vitro response of human peripheral blood mononuclear cells to AISI 316L austenitic stainless steel subjected to nitriding and collagen coating treatments
Surface modification treatments can be used to improve the biocompatibility of austenitic stainless steels. In the present research two different modifications of AISI 316L stainless steel were considered, low temperature nitriding and collagen-I coating, applied as single treatment or in conjunction. Low temperature nitriding produced modified surface layers consisting mainly of S phase, which enhanced corrosion resistance in PBS solution. Biocompatibility was assessed using human peripheral blood mononuclear cells (PBMC) in culture. Proliferation, lactate dehydrogenase (LDH) levels, release of cytokines (TNF-α, IL-1β, IL-12, IL-10), secretion of metalloproteinase (MMP)-9 and its inhibitor TIMP-1, and the gelatinolytic activity of MMP-9 were determined. While the 48-h incubation of PBMC with all the sample types did not negatively influence cell proliferation, LDH and MMP-9 levels, suggesting therefore a good biocompatibility, the release of the pro-inflammatory cytokines was always remarkable when compared to that of control cells. However, in the presence of the nitrided and collagen coated samples, the release of the pro-inflammatory cytokine IL-1β decreased, while that of the anti-inflammatory cytokine IL-10 increased, in comparison with the untreated AISI 316L samples. Our results suggest that some biological parameters were ameliorated by these surface treatments of AISI 316L.