Design Of Safety Systems Research Articles

Application of Digital Twins in Designing Safety Systems for Robotic Stations

The aim of this paper is to present examples and original solutions related to the application of the digital twin concept in designing safety systems for robotic stations. This paper includes a review of publications on robot safety systems and digital twins. Based on this review, it was concluded that further work in this area is justified. This paper demonstrates the use of a digital model of a robotic casting mold preparation station to design safety components for an industrial cell. A key element of this paper is the presentation of developed algorithms and their applications in building digital twins of existing robotic stations. By characterizing advanced safety systems used in robotic stations, an example of using a digital twin of a robotic station to create safety zones and so-called restricted zones for the robot was developed. As part of the research conducted, a real, comprehensive example of creating safety zones based on the robot’s TCP paths was carried out.

On Trade-Off Relationship between Static and Dynamic Lateral Stabilities of Articulated Heavy Vehicles

Articulated heavy vehicles exhibit poor lateral stability, which may lead to unstable motion modes, e.g., trailer-sway and jackknifing, causing severe accidents. Varying relevant vehicle parameters improves the static stability but degrades the dynamic stability. The past studies focused either on the static or dynamic stability alone. However, little attention has been paid to exploring the trade-off between the static and dynamic stabilities. To gain design insights for active safety systems for AHVs, this article studies this trade-off systematically. To this end, a systematic method is proposed to conduct the linear stability and trade-off analysis. To implement and demonstrate the proposed method, a linear three-degrees-of-freedom yaw-plane model is generated to represent a tractor/semi-trailer. A trade-off analysis is conducted considering two tractor rear-axle configurations and three trailer payload arrangements. In each case, simulation is performed in both steady-state and transient testing maneuvers. To validate the linear stability analysis based on the linear yaw-plane model, two nonlinear TruckSim models are introduced, and the corresponding simulation is conducted. Insightful understanding of the trade-off is gained through analyzing the simulation results, and the linear stability analysis will provide valuable guidelines for the design and development of active safety systems for AHVs.

Research on the Remaining Useful Life Prediction Method of Energy Storage Battery Based on Multimodel Integration.

The remaining useful life (RUL) of lithium-ion batteries (LIBs) needs to be accurately predicted to enhance equipment safety and battery management system design. Currently, a single machine learning approach (including an improved machine learning approach) has poor generalization performance due to stochasticity, and the combined prediction approach lacks sufficient theoretical support at the same time. In this paper, we first analyze the prediction principles and applicability of models such as long and short-term memory networks and random forests, and then propose a method for predicting the RUL of batteries based on the integration of multiple-model, and finally validate the proposed model by using experimental data. The experimental results show that (1) for the proposed model, in the best case, the root-mean-square error (RMSE) does not exceed 0.14%, which has a stronger generalization; (2) for the comparison with the single model used, the average RMSE is reduced by 46.2%, 43.7%, and 80.6%, which has a better fitting performance. These results show that the model has good prediction accuracy and application prospects for predicting the RUL of energy storage batteries.

Failure mechanism and thermal runaway behavior of lithium-ion battery induced by arc faults

As the widespread of lithium-ion battery systems such as electric vehicles and energy storage systems, the number of safety incidents due to electrical faults are increasing. Many accident reports have demonstrated that arc faults have become one of the main triggers of LIB system accidents, however, the related studies are inadequate. In this study, an arc imitation system is employed to investigate the influence of different arc energies on battery safety valve, as well as the electrochemical characteristics of faulty batteries. The results show that the minimum arc power to breach the safety valve ranges from 110 to 441 W. The maximum temperature rise rate on the battery surface can exceed 15 °C/s with arc power of around 1000 W. Further, the testing of in-situ and ex-situ indicate the faulty batteries undergo degradation and failure due to that moisture in the air enters the battery interior, resulting in increased internal resistance, loss of active materials and cyclable lithium. Finally, the faulty battery has no valve opening during thermal runaway, and the ignition time is four hundred seconds earlier than that of the normal battery, indicating more severe fire dangers. The results are valuable for safety design of battery systems in relation to arc faults, as well as the characteristic for fault detection and early warning.

Critical Factors Influencing the Choice of Fire Safety Systems Design in Ghanain Public Buildings

Recently, a day passed without fire outbreaks in Ghana generated many discussions on rumours relating to politics, sabotage or religious differences among others, yet little is done to reduce this high incidence of fire outbreaks. One quandary identified is that, there is no uniform standard for building safety design, and ambiguous acceptance criteria used by building designers enthralling them to design what they think it is vital to them, hence, ignoring regulations and standards as their benchmark. The study adopted a quantitative descriptive approach, and questionnaires items tested by principal architects and chief service engineers, totalling one –hundred and thirty-four (134) of which 95 for architects and 39 for services engineers with good standing firms, belonging to registered professional bodies across the country. The sampling frame was deduced from the list of currently Registered Architectural Consultancy Firms with good standing in the building construction industries in Ghana and the list of Service Engineering firms in Ghana Association of Incorporated Engineers in two cities namely, Kumasi, and Accra in Ghana, due to its highly concentrated architectural and service engineering firms. Kish (1965) formula was used for calculating minimum sample size for the study. SPSS Version 21.6 package was used to produce the statistical analysis tools for the study. Descriptive statistics such as frequency and percentages were used to summarize the data gathered from respondents. However, the influential critical factors identified from the literature, regulations, and international standards codes are grouped under ten components as follows;- 1) Holistic Design variables, 2) Relevance design considerations variables, 3) Fire safety objectives variables, 4) Performance based code variables, 5) Fire detection, alarm systems and suppression systems variables, 6) Active Fire Protection variables, 7) Building Fire Safety consideration variables, 8) Fire Emergency Power Design variables, 9) Built-in’ Fire Protection or ‘Passive Fire Protection’ (PFP) variables, and 10) Fire risk activities variables. The results of this study would enable fire safety designers in Ghana to be successful in its quest to incorporate these identified influential factors in their designs. The study seeks to find out critical influential factors related to design of building fire safety that contribute to BSI’s in Ghana: purposeful of given initial screening evaluation for fire safety and health performance throughout the entire design process.

Electrical Fire Safety Considerations in the Fire Protection System Design of High-rise Buildings

High-rise buildings, as significant symbols of urban development, demand critical attention to the electrical fire safety design of their fire protection systems. This paper aims to explore the electrical fire safety design in the fire protection systems of high-rise buildings to enhance fire safety. By comprehensively analyzing the principles and methods of electrical fire safety design, the feasibility and effectiveness of such systems in high-rise buildings are examined. This study also considers modern technologies and innovations to improve the performance of electrical fire safety systems. Finally, several recommendations are proposed to strengthen the practical application of electrical fire safety design in high-rise buildings.

Characterization of Breakdown Arcs Induced by Venting Particles Generated by Thermal Runaway of Large-Capacity Ternary Lithium-Ion Batteries

In recent years, with the continuous growth in power demand, lithium-ion batteries (LIBs) have become an indispensable component of various electronic devices, transportation vehicles, and energy systems. The safety performance of LIBs is one of the most significant issues facing their continued development. In battery systems, the presence of arcs constitutes a significant safety hazard that necessitates attention; the thermal runaway (TR) of LIBs releases a large quantity of particles with elevated temperature and high velocity, probably resulting in arc failures. Changes in the insulation structure inside battery packs and the accumulation of particulate matter resulting from the TR of battery cells are potential causes of arc-induced disasters. In this study, we utilized fully charged 71 Ah ternary LIB Li (Ni0.8Co0.1Mn0.1) O2 (NCM811) pouch cell samples and collected the vented particles in an inert atmosphere after TR. All the settled particles were classified into six groups; by conducting experiments with different particle sizes, electrode spacings, and circuit loads, the patterns of the particle-induced arcs were understood. The results indicate that as the particle size increases, the critical breakdown voltage decreases. Regarding electrode spacing and circuit load resistance, larger values require higher critical breakdown voltages. The research results provide valuable guidance for the electrical protection and safety design of battery systems.

Investigating the Actuation of Sidewall Sprinkler in an Atrium Using CFD Simulation

This study investigates the actuation of sidewall sprinklers in large-scale buildings with high-ceilinged atriums, addressing the challenges of unique architectural configurations. Compliance with NFPA 101 requires automatic sprinkler systems, including atrium areas, in these buildings. To maintain aesthetic considerations, design engineers, particularly in the middle east, often propose sidewall sprinklers as an alternative to traditional ceiling sprinklers. This research assesses whether the sidewall sprinklers would actuate during a fire using Fire Dynamic Simulator (FDS). The findings indicate that sidewall sprinklers will fail to actuate if the fire is located at the centre of the atrium, even if the edge of the fire area is below the sprinklers. Furthermore, the study emphasizes the importance of using an FDS mesh resolution (D*/dx) of 6 or finer resolution when measuring temperatures near the flame or fire plume to ensure accurate evaluations of sprinkler activation. These findings provide valuable insights for design engineers and authorities, assisting in decision-making processes related to fire safety measures, system designs, and regulatory compliance.

Concept of Multifactor Method and Non-Functional Requirements Solution to Increase Resilience through Functional Safety with Cybersecurity Analysis

In the process of designing safety systems, an integrated approach in safety and cybersecurity analysis is necessary. The paper describes a new technique of increasing resilience through integrated analysis of functional safety and cybersecurity. It is a modeling methodology based on the combination of the multifactor method utilizing modified risk graphs, used previously for Safety Integrity Level (SIL) assessment, and the Non-Functional Requirements (NFR) approach. The NFR approach, based on the analysis of graphical representation of conceptual and physical components of the system, contributes a technique to include cybersecurity through the Softgoal Interdependency Graph. The assessment methodology is outlined in detail and applied to a case study involving an industrial control system. The analysis turns out to be effective in both aspects: confirming the findings of the multifactor approach based on modified risk graphs and complementing the traditional analysis to increase resilience in discovering and mitigating security vulnerabilities for SIL assessment by the use of NFR.

Design and Implementation of an Iot-Based Safety and Energy Efficient System

The paper provides a safe and power-efficient Internet of Things (IoT)-based solution. With the growing concerns about environmental sustainability and the demand for improved safety measures in today’s society, it has become critical to focus on building systems that decrease energy consumption and assure the safety of humans and the environment. The proposed system employs cutting-edge technologies and novel approaches that will result in optimal energy usage with minimal or no human involvement thereby assuring the safety of people. The proposed system leverages on existing IoT technologies and is comprised of smart sensors, energy-efficient gadgets, and a centralized control unit. Therefore, it is able to demonstrate cutting edge power control strategies including power gating and dynamic central power regulation which control the usage of gadgets to operate at optimal power levels vis-a-vis the real-time demand to achieve energy efficiency. The system is also able to collect data on occupancy, lighting, temperature, and power consumption trends which can assist in making data-driven choices that improve the usage of energy. The proposed system provides large energy savings without sacrificing user comfort by dynamically altering lighting, and cooling systems based on occupants and ambient factors. Multiple simulations and real-world trials in homes and institutions’ buildings were used to assess the efficacy of the suggested system. The findings revealed substantial reductions in energy consumption without jeopardizing safety.

Safety hysteresis comparator design for transient overvoltage detection

This research introduces a safety hysteresis comparator that detects transient overvoltage in the track circuit relay interlocking of railway signaling system. This overvoltage is caused by voltage faults transmitted through the electric conductor on the track feed unit to the receiver equipped with the track relay, which acts as the occupied track circuit controller. The circuit was designed using safety system design principles and concepts. Findings illustrated that the transient overvoltage detection of the safety hysteresis comparator in the track circuit activated when the input voltage (Vin) was higher than the high hysteresis signal level (Vhyst_H). When Vin was less than low hysteresis signal level (VVhyst_L), the output voltage (Vo) state was low. Otherwise, it was high. The hysteresis voltage was 4.4 V. The installation of the transient overvoltage detector in the track circuit was to monitor the transient overvoltage fault in the track circuit and to confirm that the hysteresis comparator was in the safety failure mode, which was the safety function for the track circuit to be compliant with the IEC 61800-5-2 standard to ensure the system stability and reliability. It would maximize the performance of the controlling function and commanding of train arrangement of State Railway of Thailand (SRT).

Explaining and predicting the increased thorax injury in aged females: age and subject-specific thorax geometry coupled with improved bone constitutive models and age-specific material properties evaluated in side impact conditions.

Predicting and understanding thorax injury is fundamental for the assessment and development of safety systems to mitigate injury risk to the increasing and vulnerable aged population. While computational human models have contributed to the understanding of injury biomechanics, contemporary human body models have struggled to predict rib fractures and explain the increased incidence of injury in the aged population. The present study enhanced young and aged human body models (HBMs) by integrating a biofidelic cortical bone constitutive model and population-based bone material properties. The HBMs were evaluated using side impact sled tests assessed using chest compression and number of rib fractures. The increase in thoracic kyphosis and the associated change in rib angle with increasing age, led to increased rib torsional moment increasing the rib shear stress. Coupled with and improved cortical bone constitutive model and aged material properties, the higher resulting shear stress led to an increased number of rib fractures in the aged model. The importance of shear stress resulting from torsional load was further investigated using an isolated rib model. In contrast, HBM chest compression, a common thorax injury-associated metric, was insensitive to the aging factors studied. This study proposes an explanation for the increased incidence of thorax injury with increasing age reported in epidemiological data, and provides an enhanced understanding of human rib mechanics that will benefit assessment and design of future safety systems.

Estimation of vehicle tire effective rolling radius and vertical wheel/road contact force

In a vehicle, knowledge of physical wheel/road contact parameters is valuable for the design of dynamic control and active safety systems. In this paper, a new method is designed to estimate the effective rolling radius and the vertical wheel/road contact force using an extended Kalman filter and the Pacejka magic formula. Moreover, it allows the estimation of the longitudinal force, the rolling resistance force, and the longitudinal slip. The method is designed in four blocks. First, a comparison with other research is carried out to validate both the controller and quarter-vehicle model blocks. Then, the blocks of the extended Kalman filter and the Pacejka magic formula are applied to estimate all parameters. The relative mean estimation errors are calculated, and the results show that the developed method is capable of estimating all parameters simultaneously and in real-time with satisfactory accuracy.

The Overview of Challenges in Detecting Patients' Hazards During Robot-Aided Remote Home Motor Rehabilitation

Home, minimally‐supervised rehabilitation has become an arising technological trend due to the shortages in medical staff. Implementing such requires providing advanced tools for automatic real‐time safety monitoring. The paper presents an approach to designing the mentioned safety system based on measurements and modelling the interface between a patient’s musculoskeletal system and a rehabilitation device. The content covers the segmentation of patients regarding their health conditions and assigns them suitable measurement techniques. The defined groups are described with the hazards, which they are most endangered, and their causes. Each case is correlated with the appropriate data type that may be used to detect potential risk. Moreover, a concept of using presented knowledge for tracking the safety of bones and soft tissues according to the biomechanical standards is included. The paper forms a set of guidelines for designing safety systems based on measurements for robot‐aided home kinesiotherapy. It can be used to select an appropriate approach regarding a specific case; so to decrease costs and increase the accuracy of the designed tools.

Numerical analysis and evaluation of a semi-heavy guardrail system

The continuous increase in traffic accidents, following the rise in the number of vehicles in traffic and their speed, requires the development of research on the design of active and passive safety systems. This research mainly aims to compare the performance of commonly used passive safety systems (semi-heavy W-beam guardrails) mounted on roadside and pedestrian bridges to protect vehicles and pedestrians. It is intended to reduce the deformations of the vehicle upon impact with the protective device mounted between the roadside and the pedestrian area for the protection of the vehicle occupants; reduce the parapet working width for the pedestrian’s safety; and maintain the vehicle’s trajectory from the moment of impact to the final movement, between the guardrail and the median axis of the road, to ensure the protection of other road users. A CAD model of the vehicle-guardrail scenario was developed to achieve these objectives. Load simulation cases are performed using the finite element method according to the European standards SR EN 1317 for impact tests of vehicles - TB 42, recommended for semi-heavy guardrails.

Numerical analysis of injuries of e-scooter riders in frontal impacts against SUVs

The rising popularity of e-scooters in urban areas highlights the importance of understanding potential collision dynamics and consequences to enhance rider safety, especially since 80% of fatalities for these vulnerable road users result from incidents involving motor vehicles. This study aims to identify potential injury mechanisms of e-scooter riders involved in frontal impacts against Sports Utility Vehicles (SUVs) using Finite Element Analysis (FEA) and a Human Body Model (HBM). Six impact scenarios at 25 km/h were simulated: on the passenger's side door (1-SD), on the trunk door (2-TD), on the bonnet (3-FB), on the bonnet from the side (4-SB), on the windshield from the side (5-SW), and finally, on the bonnet with an offset (6-FO). A wide range of Injury Risk Criteria (IRCs) was analyzed, including A3MS, HIC15, BrIC, DAMAGE, Cmax and PC Score, and head contact forces were output. Injury Risk Curves were then used to calculate the probability and severity of the sustained injuries predicted by the mentioned IRCs. Overall, the results corresponding to the most injurious scenarios suggested serious (30% to 40% overall probability) and critical (45% probability for the 4-SB scenario) brain, moderate head (30% probability for scenarios 1-SD and 2-TD), and serious thoracic (26% to 78% overall probability) injuries. Additionally, in two scenarios (1-SD and 2-TD), the e-scooter rider's mandible impacted against the vehicle's roof side rail and rear spoiler, involving potential anterior-posterior serious mandible fractures. The conclusions reached in this study help to understand potential injury sources and provide valuable information for the design of specific safety systems or the creation or improvement of e-scooter legislation.

Enhanced Soft Error Rate Estimation Technique for Aerospace Electronics Safety Design via Emulation Fault Injection

In this paper, we propose Automatic Configuration Memory Fault Injection (ACMFI), a tool that calculates the architectural vulnerability factor (AVF) and soft error rate (SER) using the emulation fault injection technique. SER, which is essential for the safety design of aerospace electronics, can be obtained by experiments (beam tests) performed in a beam facility equipped with high-energy radiation facilities. However, SER calculation using beam tests has the disadvantage of a high cost and a long waiting time, making it difficult to use in the conceptual design stage, which is the aerospace system development stage and the initial HW/SW development stage. Using the emulation fault injection method, it is possible to estimate the SER, which can be used in the system safety design phase. This paper describes the ACMFI tool, which automatically performs emulation fault injection in SRAM-based FPGAs, which are widely used in aerospace electronic hardware. Unlike the existing methods, the proposed method has the advantage of minimizing the side effects by injecting faults into a dedicated SRAM area. In other words, the SER obtained by the proposed method can be estimated more accurately than the SER result obtained by the existing method. To prove the accuracy of the proposed test method, the SER calculated by performing an emulation fault injection test on the same FPGA was compared with the SER results tested at the beam facility. The method of obtaining SER using the proposed ACMFI gave results that were closer to the SER obtained by testing at the beam facility than the method of obtaining SER using the existing EMFI. The proposed method is used to calculate the failure rate, which is a key variable in determining the development assurance level when performing safety design tests in aerospace system development, enabling the development of safer systems and lower cost/higher quality aerospace electronic equipment than before.

Safety on the ground: using critical incident technique to explore the factors influencing medical registrars’ provision of safe care

BackgroundAvoidable patient harm in hospitals is common, and doctors in training can provide underused but crucial insights into the influencers of patient safety as those working ‘on the ground’ within...

Real-Time Detection of Circulating Thrombi in an Extracorporeal Circuit Using Doppler Ultrasound: In-Vitro Proof of Concept Study.

Thromboembolic stroke continues to be by far the most common severe adverse event in patients supported with mechanical circulatory assist devices. Feasibility of using Doppler ultrasound to detect circulating thrombi in an extracorporeal circuit was investigated. A mock extracorporeal circulatory loop of uncoated cardiopulmonary bypass tubing and a roller pump was setup. A Doppler bubble counter was used to monitor the mean ultrasound backscatter signal (MUBS). The study involved two sets of experiments. In Scenario 1, the circuit was sequentially primed with human blood components, and the MUBS was measured. In Scenario 2, the circuit was primed with heparinized fresh porcine blood, and the MUBS was measured. Fresh blood clots (diameter <1,000 microns, 1,000-5,000 microns, >5,000 microns) were injected into the circuit followed by protamine administration. In Scenario 1 (n = 3), human platelets produced a baseline MUBS of 1.5 to 3.5 volts/s. Addition of packed human red blood cells increased the baseline backscatter to 17 to 21 volts/s. Addition of fresh frozen plasma did not change the baseline backscatter. In Scenario 2 (n = 5), the blood-primed circuit produced a steady baseline MUBS. Injection of the clots resulted in abrupt and transient increase (range: 3-30 volts/s) of the baseline MUBS. Protamine administration resulted in a sustained increase of MUBS followed by circuit thrombosis. Doppler ultrasound may be used for real-time detection of circulating solid microemboli in the extracorporeal circuit. This technology could potentially be used to design safety systems that can reduce the risk of thromboembolic stroke associated with mechanical circulatory support therapy.

Optimization of Occupant Restraint System Using Machine Learning for THOR-M50 and Euro NCAP

In this study, we propose an optimization method for occupant protection systems using a machine learning technique. First, a crash simulation model was developed for a Euro NCAP MPDB frontal crash test condition. Second, a series of parametric simulations were performed using a THOR dummy model with varying occupant safety system design parameters, such as belt attachment locations, belt load limits, crash pulse, and so on. Third, metamodels were developed using neural networks to predict injury criteria for a given occupant safety system design. Fourth, the occupant safety system was optimized using metamodels, and the optimal design was verified using a subsequent crash simulation. Lastly, the effects of design variables on injury criteria were investigated using the Shapely method. The Euro NCAP score of the THOR dummy model was improved from 14.3 to 16 points. The main improvement resulted from a reduced risk of injury to the chest and leg regions. Higher D-ring and rearward anchor placements benefited the chest and leg regions, respectively, while a rear-loaded crash pulse was beneficial for both areas. The sensitivity analysis through the Shapley method quantitatively estimated the contribution of each design variable regarding improvements in injury metric values for the THOR dummy.