Loss Of Control Events Research Articles

Safer operating areas (SOA) of cylindrical lithium-ion battery – A probabilistic approach

This study introduces a real-time probabilistic safety assessment of a 18650 cylindrical battery. The physics-based failure scenarios from battery abuse are mapped onto Bayesian Network framework, enabling a quantitative estimation of monitoring parameters, health indicators and loss of control events. The model (encompassing multiple states, weightage factors, interdependencies, and uncertainties) is validated with 70 experimental data points of the same geometry, comprising 4 categories of abuses (surface heating, fast overcharging, external short circuit, and internal deformation). Through testing, probabilistic safety thresholds are established for 3 observed events: gas formation, venting, and fire and explosion.Sensitivity analysis reveals state of charge (at SOC > 50 %) and surface temperature (at Tsurf > 90°C) as the most influential parameters while inadequate cooling system and current interrupt device (CID) as influential safeguards for thermal runaway and fire to occur. Moreover, the identified safety thresholds are subjected to validation and testing against multiple health indicators to draw important insights. Probability, P(fire)deformation>P(fire)surface heat as internal deformation lowers onset to thermal runaway. In culmination, a safer operating area (SOA) is proposed, leveraging the identified thresholds and most sensitive parameters. The proposed SOA with 4 distinct boundaries is not only consistent with the temporal variations in cell temperature during thermal abuse test, but also provides a robust approach to monitor the safety of a battery.

Loss-of-Control Prediction of a Quadcopter Using Recurrent Neural Networks

Loss of control (LOC) is a prevalent cause of drone crashes. Onboard prevention systems should be designed requiring low computing power, for which data-driven techniques provide a promising solution. This study proposes the use of recurrent neural networks (RNNs) for LOC prediction. Four architectures were trained in order to identify which RNN configuration is most suitable and if this model can predict LOC for changing aerodynamic characteristics, wind conditions, quadcopter types, and LOC events. One-hundred and seventy-two real-world LOC events were conducted using a 53 g Tiny Whoop, a 73 g URUAV UZ85, and a 265 g GEPRC CineGO quadcopter. For these flights, LOC was initiated by demanding an excessive yaw rate (2000 deg/s), which provokes an unrecoverable upset and subsequent crash. All RNNs were trained using only onboard sensor measurements. It was found that the commanded rotor values provided the clearest early warning signals for LOC because these values showed saturation before LOC. Moreover, all four architectures could correctly and reliably predict the impending LOC event 2 s before it actually occurred. Furthermore, to investigate generality of the methodology, the predictors were successfully applied to flight data in which the quadcopter mass, blade diameter, and blade count were varied.

Injury mechanisms in fatal Australian quad bike incidents

ABSTRACTObjectives: The ability to determine risk management controls for quad bike use is confounded by limitations in crash and injury information. The aim of this article is to identify the injury mechanisms, crash characteristics, and contributing factors in fatal quad bike incidents in Australia by activity (recreation and work).Methods: An in-depth case series study was undertaken of 106 Australian quad bike fatalities that had occurred between 2000 and 2013. All case material held by Australian coroners was obtained and reviewed.Results: One hundred and six cases were categorized as occurring during recreation (53) and work (53). Fifty-two of the work cases occurred during farmwork. The mean age for those killed during a work activity was 56 years compared to 27 years for recreational riders. Two children under 16 years died while performing farmwork and 13 children under 16 years during recreational activities. The analyses show a very clear pattern for farmwork-related deaths: quad bike rolls or pitches over (farmworker, 85%; recreational rider, 55%), rider becomes pinned under quad bike (farmworker, 68%; recreational rider, 30%), and death by asphyxia (farmworker, 42%; recreational rider, 11%). In contrast, recreational riders suffered complex impact injuries to the head and chest that occurred when the rider was traveling at speed, lost control, was ejected, and collided with an object in the environment and/or interacted with the moving quad bike.Conclusions: The analyses support the need to improve safe quad bike operation through consideration of the age of the rider, training, helmet use, reducing the propensity of quad bikes to roll, and improving handling so that loss of control events are reduced and to prevent crushing and pinning by the vehicle during and after a rollover crash.

Unrealistic Optimism, Fatalism, and Risk-Taking in New Zealand Farmers’ Descriptions of Quad-Bike Incidents: A Directed Qualitative Content Analysis

ABSTRACTQuad-bike incidents are a major cause of occupational injury and fatality on farms warranting health and safety attention. As part of a larger study, we carried out a face-to-face survey with 216 farmers in New Zealand. We quantitatively identified farmers’ propensity for risk-taking, unrealistic optimism, and fatalism as risk factors in quad-bike loss-of-control events (LCEs). The purpose of the analysis presented in this article was to use these same farmers’ recollections of LCEs to explore the a priori constructs in more detail using qualitative methods. Participants reporting one or more LCEs described their first LCE and any experienced in the previous 12 months. Participants provided open-text responses about what occurred at each LCE, their reflections, and general thoughts on LCE risk factors. Directed qualitative content analysis (QCA) was used to “unpack” risk-taking, unrealistic optimism, and fatalism whilst also delineating any additional concepts that farmers associate with LCEs. Risk-taking elements were more evident than unrealistic optimism or fatalism and more suggestive of farmers finding themselves in risky situations rather than engaging in risk-seeking behavior per se. Additional inductively derived categories of fatigue/stress, multitasking, inexperience, and quad-bike faults highlight the complex nature of LCEs and the importance of risk assessment covering these concepts as well as risky situations.

Can a glass cockpit display help (or hinder) performance of novices in simulated flight training?

The analog dials in traditional GA aircraft cockpits are being replaced by integrated electronic displays, commonly referred to as glass cockpits. Pilots may be trained on glass cockpit aircraft or encounter them after training on traditional displays. The effects of glass cockpit displays on initial performance and potential transfer effects between cockpit display configurations have yet to be adequately investigated. Flight-naïve participants were trained on either a simulated traditional display cockpit or a simulated glass display cockpit. Flight performance was measured in a test flight using either the same or different cockpit display. Loss of control events and accuracy in controlling altitude, airspeed and heading, workload, and situational awareness were assessed. Preferences for cockpit display configurations and opinions on ease of use were also measured. The results revealed consistently poorer performance on the test flight for participants using the glass cockpit compared to the traditional cockpit. In contrast the post-flight questionnaire data revealed a strong subjective preference for the glass cockpit over the traditional cockpit displays. There was only a weak effect of prior training. The specific glass cockpit display used in this study was subjectively appealing but yielded poorer flight performance in participants with no previous flight experience than a traditional display. Performance data can contradict opinion data. The design of glass cockpit displays may present some difficulties for pilots in the very early stages of training.

Are agricultural quad bike loss-of-control events driven by unrealistic optimism?

Quad bikes are used extensively in agriculture. Use of these vehicles, however, carries some risk. The promotion of safety behaviours has not reduced this risk. This study tested the hypotheses that farmers with greater unrealistic optimism (UO), fatalistic beliefs or a propensity for risk-taking are more susceptible to quad bike loss-of-control events (LCEs). A cross-sectional study recruited 216 farmers from the Otago and Southland regions of New Zealand. A face-to-face structured interview was carried out to record psychological constructs and history of LCEs. Data were analysed using regression methods. Fifty-two farmers (24%) reported no LCEs, the remaining 164 farmers (76%) reported between 1 and 50 events. Generally, farmers did not have risk-taking personalities or fatalistic beliefs but did appear to have an “it won’t happen to me” attitude towards their risk of quad bike incidents. Number of LCEs was significantly associated with lower UO (IRR 0.84, 95%CI: 0.75, 0.94), higher impulsive sensation seeking (IRR 1.08, 95%CI: 1.01, 1.16), younger age (IRR 0.98, 95%CI: 0.97, 0.99) and male sex (IRR 4.00, 95%CI: 2.15, 7.44). The effect of UO was being driven by a positive relationship between number of LCEs and greater belief in personal risk of having LCEs. Contrary to hypotheses, farmers with stronger beliefs that “it won’t happen to me” were less likely to have had LCEs. Further exploration into the factors that contribute to farmers’ perception of LCE risk and its impact on quad bike safety behaviour is warranted. This may allow for more targeted interventions.

Is workplace satisfaction associated with self-reported quad bike loss of control events among farm workers in New Zealand?

This study investigated whether rural workers who have higher workplace satisfaction are less likely to report quad bike loss of control events (LCEs). Two independent samples of farmers completed a survey regarding LCEs and workplace satisfaction. In the first sample (n = 130) analysis revealed no relationship (p = 0.74) between workplace satisfaction and LCEs but lower rates of LCEs were reported by employees (IRR 0.52, 95%CI 0.31–0.86) compared to self-employed participants. In the second sample (n = 112), workplace satisfaction was weakly related to LCEs (IRR 1.04, 95%CI 1.00, to 1.09) with participants who found their job more psychologically demanding more likely to have had an LCE (IRR 1.14, 95%CI 1.05–1.23). Exploring the role of psychological demands on safety behaviour with respect to quad bike use, may help to address this important safety issue.

Factors associated with quad bike loss of control events in agriculture

Objective To determine personal and workplace factors associated with quad bike loss of control events (LCEs) on New Zealand farms. Methods Rural community databases were used to sample 130 farmers and farm employees (workers). Fieldwork and survey investigated for prevalence of LCEs; farm type; farm terrain; personal measures; and vehicle driving exposures. Results Seventy nine workers (61%) described a total of 200 LCEs. Increased driver height, increased body mass, non-flat farm terrain, increased driving speed and distance, and greater whole body vibration exposure were significantly associated with LCEs. Conclusions Taller and heavier drivers of quad bikes should be particularly vigilant for risk of an LCE. Vehicle speed, distance driven and choice of driving routes over difficult terrain are potentially modifiable factors which have behavioural components and should be considered as management strategies for reducing risk of on-farm quad bike LCEs. Relevance to industry Quad bike accidents are a considerable problem in agriculture. This research has identified a number of physical and driving factors that should be considered in the management strategies for reducing risk of on-farm quad bike accidents.

All terrain vehicle loss of control events in agriculture: Contribution of pitch, roll and velocity

All terrain vehicle (ATV) (i.e. quad bike) loss of control (LOC) events are a major cause of injury and death on New Zealand and Australian farms. ATV LOC history, work experience, anthropometric data and vehicle pitch, roll and velocity data were recorded from 30 farmers. The terrain induced 95th percentiles were forward pitch 27.8°, backward pitch 28.7° and 20.8° for left and right roll. Nineteen participants (mean 42.4 years) had experienced 53 LOC events and were on average 9.5 years younger than the 11 participants (mean 51.9 years) who had not previously experienced LOC. Peak pitch, roll and velocity were not associated with LOC; however, at peak left roll the non-LOC group had a pitch of 3.1° downhill, while the LOC group had a pitch of 2.1° uphill. Results indicate ATV LOC prevalence is considerably underestimated, while increased risk for LOC may be influenced by a combination of personal, mechanical or terrain factors. The ATV pitch, roll and slope traverse data may help in the better understanding of why LOC events occur, may help in the development of safety equipment such as a tilt warning device and will contribute to national safety guidelines. Statement of Relevance: Approximately 80,000 ATVs are used in rural New Zealand and ATV accidents are the single most common cause of work-related fatalities, apart from road accidents. This fieldwork research provides pitch, roll and velocity data and considers how these data might contribute to risk of ATV accidents.

Poor me versus bad me paranoia and the instability of persecutory ideation

To investigate whether there are two stable types of paranoia, 'poor me' and 'bad me', as described by Trower and Chadwick (1995), and whether beliefs about the deservedness of persecution are associated with psychological measures. In-patients experiencing persecutory delusions were assigned either to 'poor me' (PM) or 'bad me'(BM) groups, according to their rating of a perceived deservedness scale, which was repeated on subsequent assessments. Participants were assessed for depression (BDI); construction of the self (Self-to-Others Scale); autonomy and sociotropy (PSI); perceived parental behaviour (PBI); attributional style (ASQ) and, meaningful daily events (DEI, devised for the study). A healthy control group was also assessed. Many patients' perceived deservedness of persecution varied across time, so that some patients were PM at one point in time but BM at another. BM paranoia was associated with high levels of depression. PM and BM patients groups both scored higher than the controls on the subscales of Self-to-Others Scale and on the PSI. PM patients exhibited a marked self-serving bias on the ASQ, and reported less parental care on the PSI, compared to the BM patients. Both groups reported less PBI mother care than the controls. BM patients reported more failure events than PM patients or controls. PM patients reported more loss of control events than the than BM patients and controls. PM and BM paranoia may represent separate phases of an unstable phenomenon. The findings are consistent with an attributional account of paranoid thinking.

The time ambiguity

The analog dials in traditional GA aircraft cockpits are being replaced by integrated electronic displays, commonly referred to as glass cockpits. Pilots may be trained on glass cockpit aircraft or encounter them after training on traditional displays. The effects of glass cockpit displays on initial performance and potential transfer effects between cockpit display configurations have yet to be adequately investigated. Flight-naïve participants were trained on either a simulated traditional display cockpit or a simulated glass display cockpit. Flight performance was measured in a test flight using either the same or different cockpit display. Loss of control events and accuracy in controlling altitude, airspeed and heading, workload, and situational awareness were assessed. Preferences for cockpit display configurations and opinions on ease of use were also measured. The results revealed consistently poorer performance on the test flight for participants using the glass cockpit compared to the traditional cockpit. In contrast the post-flight questionnaire data revealed a strong subjective preference for the glass cockpit over the traditional cockpit displays. There was only a weak effect of prior training. The specific glass cockpit display used in this study was subjectively appealing but yielded poorer flight performance in participants with no previous flight experience than a traditional display. Performance data can contradict opinion data. The design of glass cockpit displays may present some difficulties for pilots in the very early stages of training.