RESUMEN
Biomechanical limits based on pain thresholds ensure safety in workplaces where humans and cobots (collaborative robots) work together. Standardization bodies' decision to rely on pain thresholds stems from the assumption that such limits inherently protect humans from injury. This assumption has never been verified, though. This article reports on a study with 22 human subjects in which we studied injury onset in four locations of the hand-arm system using an impact pendulum. During the tests, the impact intensity was slowly increased over several weeks until a blunt injury, i.e., bruising or swelling, appeared in the body locations under load. A statistical model, which calculates injury limits for a given percentile, was developed based on the data. A comparison of our injury limits for the 25th percentile with existing pain limits confirms that pain limits provide suitable protection against impact injuries, albeit not for all body locations.
Asunto(s)
Extremidad Superior , Heridas no Penetrantes , Humanos , Mano , Modelos Estadísticos , Dolor , Fenómenos BiomecánicosRESUMEN
Collaborative robots (cobots) provide a wide range of opportunities to improve the ergonomics and efficiency of manual work stations. ISO/TS 15066 defines power and force limiting (PFL) as one of four safeguarding modes for these robots. PFL specifies biomechanical limits for hazardous impacts and pinching contacts that a cobot must not exceed to protect humans from serious injuries. Most of the limits in ISO/TS 15066 are preliminary, since they are based on unverified data from a literature survey. This article presents a human-subject study that provides new and experimentally verified limits for biomechanically safe interactions between humans and cobots. The new limits are specifically tailored to impact and pinching transferred through blunt and semi-sharp surfaces as they can occur in the event of human error or technical failures. Altogether 112 subjects participated in the study and were subjected to tests with emulated impact and pinching loads at 28 different body locations. During the experiments, the contact force was gradually increased until the load evoked a slightly painful feeling on the subject's body location under test. The results confirm that the pain thresholds of males and females are different in specific body regions. Therefore, when defining biomechanical limits, the gender difference must be taken into account. A regression model was utilized to incorporate the gender effect as a covariate into a conventional statistical distribution model that can be used to calculate individual limits, precisely fitted to a specific percentile of a mixed group of male and female workers which interacting with cobots.
RESUMEN
BACKGROUND: In acute medical care, there are patients who have been injured by the influence of others. The aim of this study was to analyze all cases which were presented to the Institute for Legal Medicine of the University Halle (Saale). The cases where analyzed in relation to the victims' statistics of the state office of criminal investigation in Saxony-Anhalt. MATERIALS AND METHODS: The consultations of the Institute for Legal Medicine Halle-Wittenberg for 2012-2015 were evaluated with regard to the age and gender distribution, the reasons for the consultation and time until the request for consultations. These cases were statistically compared to the victims' statistics of the state office of criminal investigation in Saxony-Anhalt 2014-2015. RESULTS: A total of 536 cases (55.6% male and 44.4% female patients) were evaluated. In all, 62.1% of patients were under 18 years of age; 43.5% of all consultations were requested by pediatric (surgery) clinics. The most common reasons for consultation were sexual child abuse or violence against children (50.7%). Compared to the victims' statistics, significantly more children were examined by legal medicine specialists than could have been expected (p < 0.001). In adult patients, the most common causes for consultation were acts of violence (20.4%) and domestic violence (10.1%). Among adults, significantly more women and fewer men were presented than expected (p = 0.001). CONCLUSION: There were only a small number of consultations of legal medicine specialists in relation to the victims' statistics. Most of them were children and women. The temporal latency between the act of violence and the consultations was one day and more. The latency and the renunciation of the consultation of the legal medicine specialists can lead to loss of evidence.
Asunto(s)
Víctimas de Crimen , Criminales , Especialización , Adolescente , Adulto , Niño , Femenino , Medicina Legal , Alemania , Humanos , Masculino , Derivación y ConsultaRESUMEN
BACKGROUND: The initial diagnostic procedure of severely injured patients in the emergency room (ER) during the primary survey is first and foremost a clinical examination. The clinical S3 guidelines provide recommendations for the treatment of patients with severe and multiple injuries. OBJECTIVES: The study was performed to investigate the reliability of clinical key symptoms or red flags registered in the ER that lead to further diagnostic or therapeutic procedures. MATERIAL AND METHODS: An evaluation of key symptoms as a synopsis of the current literature considering aspects of probability calculation and medical experience was carried out. RESULTS: Key symptoms registered during the clinical examination are not sufficiently safe to be solely relied upon for further diagnostic and therapeutic decisions. This confirms the sense of purpose of the strict approach according to the advanced trauma life support (ATLS) algorithm. Red flags can serve as a warning to focus on relevant injuries early on. A rational imaging diagnostic procedure must follow.
