Hoist Operation Research Articles

Watercraft as Overwater Ambulance Exchange Points to Enhance Air Medical Evacuation

Ambulance exchange points are preidentified sites where patients are transferred between evacuation platforms while en route to enhanced medical care. We propose a new capability for maritime medical evacuation, which involves co-opting underway watercraft as overwater ambulance exchange points to transfer patients between medical evacuation aircraft. We partnered with the US Army's 25th Combat Aviation Brigade to demonstrate the use of Army watercraft as overwater ambulance exchange points. A manikin was transferred between 2 HH-60M medical evacuation Black Hawk helicopters conducting hoist operations over Army Logistics Support Vessel 3, which was traveling south of Honolulu, HI. The demonstration was enabled by a decision support system for dispatching aircraft, hoist stabilization technology, commercial satellite internet, military geospatial infrastructure applications, and digital medical documentation tools, the benefits of which are all discussed. Three extensions of the overwater ambulance exchange point are introduced, and civilian applications are considered.

Simulation Modeling and Temperature Over-Advance Perception of Mine Hoist System Based on Digital Twin Technology

The temperature prediction of hoist motor is one of the effective ways to ensure the safe production of mine hoist. Digital twin technology is a technology that combines the physical system of the real world with the digital model of the virtual world. Through digital twin technology, the physical system in the real world can be monitored and simulated in a virtual environment, and the state information of these systems can be monitored in real time. Recurrent neural network is a kind of neural network suitable for processing sequence data, which can automatically extract and learn the feature information in sequential data. To achieve online monitoring and over-advance perception of the temperature of the mine hoist motor, a temperature prediction and advance sensing method based on digital twins and recurrent neural network is proposed. To begin with, a high-fidelity digital twin monitoring system for mine hoists is constructed, enabling the acquisition of real-time temperature data. These temperature data are then fed into a neural network for feature extraction and precise prediction of the motor’s state. Subsequently, based on the temperature prediction module in the digital twin hoist monitoring system, a user interface (UI) is developed, and a fully functional digital twin temperature monitoring system is built and experimentally validated. The experimental results demonstrate that the digital twin system effectively monitors the real-time temperature state of the motor during the operation of the mine hoist. Furthermore, the integration of digital twin and recurrent neural network enables the accurate prediction and proactive detection of temperature variations in the motor of the mine hoist. This innovative approach introduces a novel perspective for implementing predictive maintenance in the mining industry, enhancing the safety and reliability of mine hoists. Additionally, it offers valuable technical support in improving maintenance efficiency and reducing associated costs.

Risk mitigation strategies for automated current and future mine hoists

In addition to extracting the ore from the mine, most mine hoists transport the miners from the surface to the various underground levels of the mine. When travelling downwards or upwards the mine shaft, miners are exposed to some risks: the conveyance could go down the shaft, crash in the headframe due to an out-of-control mine hoist or crash in a undetected obstacle. Mine hoists are not always commissioned with hundred percent new parts, and are sometimes retrofitted from old mechanical parts. This article presents a statistical review of mine hoists in use in the Province of Quebec, Canada, a quick review of the safety regulations and machinery safety standards applicable to mine hoists and a fault tree analysis (FTA) and risk analysis for a generic drum hoist. The risk analysis was conducted following the methodology prescribed by the IEC 62061 standard. From a practical standpoint, the main conclusion is that a SIL 3 (Safety Integrity Level) compliant command and supervision system should be used to safely cover all the hazardous situations that can happen in the day-to-day operation of a mine hoist. Based on the FTA and risk analysis findings, a proposed design of the command and supervision system for mine hoist is presented. Among the notable differences with the current mine hoist command and supervision system, the authors suggest a total separation of the command and supervision Programmable Electronic System (PES). Finally, the article proposes risk mitigation strategies to improve the safety of current and future mine hoists.

An improved BRB-based anomaly detection method of drive end bearings

The anomaly detection research of drive end bearings (DEBs) is of great significance to the safe and reliable operation of hoist. This paper proposes an anomaly detection method of DEBs based on the linear weighted sum combines with the belief rule base. First, in order to improve the accuracy of anomaly detection, the time-domain features and frequency-domain features are integrated by linear weighted sum (LWS) respectively. Then, belief rule base (BRB) method is provided for anomaly detection using fused features. Meanwhile, the covariance matrix adaption evolution strategy (CMA-ES) is utilized to optimize the parameters of belief rule base model. Finally, the validity of the proposed method is verified by the vibration data, which are acquired from the condition monitoring system of hoist in body-in-white (BIW) welding production line. The proposed method achieves a high detection accuracy. It is proved that the proposed method is suitable for anomaly detection of DEBs in the actual BIW welding production line.

Factors influencing on-scene time in a physician-staffed helicopter emergency medical service (HEMS): a retrospective observational study

BackgroundFor helicopter emergency service systems (HEMS), the prehospital time consists of response time, on-scene time and transport time. Little is known about the factors that influence on-scene time or about differences between adult and paediatric missions in a physician-staffed HEMS.MethodsWe analysed the HEMS electronic database of Swiss Air-Rescue from 01-01-2011 to 31-12-2021 (N = 110,331). We included primary missions and excluded missions with National Advisory Committee for Aeronautics score (NACA) score 0 or 7, resulting in 68,333 missions for analysis. The primary endpoint ‘on-scene time’ was defined as first physical contact with the patient until take-off to the hospital. A multivariable linear regression model was computed to examine the association of diagnosis, type and number of interventions and monitoring, and patient's characteristics with the primary endpoint.ResultsThe prehospital time and on-scene time of the missions studied were, respectively, 50.6 [IQR: 41.0–62.0] minutes and 21.0 [IQR: 15.0–28.6] minutes. Helicopter hoist operations, resuscitation, airway management, critical interventions, remote location, night-time, and paediatric patients were associated with longer on-scene times.ConclusionsCompared to adult patients, the adjusted on-scene time for paediatric patients was longer. Besides the strong impact of a helicopter hoist operation on on-scene time, the dominant factors contributing to on-scene time are the type and number of interventions and monitoring: improving individual interventions or performing them in parallel may offer great potential for reducing on-scene time. However, multiple clinical interventions and monitoring interact and are not single interventions. Compared to the impact of interventions, non-modifiable factors, such as NACA score, type of diagnosis and age, make only a minor contribution to overall on-scene time.

Human reliability assessment of intelligent coal mine hoist system based on Bayesian network

The human reliability of intelligent coal mine hoist operation system is affected by many factors, in order to reduce the occurrence of human error in the hoist system and improve the reliability of the system. The characteristics of phased-mission task operation of hoists is combined, the phase dependence of human cognitive errors is considered and, a new human reliability evaluation method is proposed with the help of Bayesian network (BN) model in this paper. Firstly, the phase dependence of human cognitive errors was analyzed based on the cognitive behavior model. Then the human error analysis in the hoist system was carried out, and several main performance shaping factors are selected. Secondly, BN was used to build the human reliability model of the hoist system at each stage. Finally, it is found that the phase dependence of cognitive errors has a negative impact on the human reliability of the hoist system through the case analysis. At the same time, several main performance shaping factors (PSFs)were quantitatively analyzed by using the reverse reasoning ability of BN, which proves the effectiveness of the proposed method, and provides a scientific and reasonable theoretical basis for the development of effective human error prevention measures for the operation of intelligent coal mine hoists.

An Adaptive Dynamic Surface Technology-Based Electromechanical Actuator Fault-Tolerant Scheme for Blair Mine Hoist Wire Rope Tension Control System

As an important equipment for deep well hoisting, the safe and stable operation of the Blair mine hoist is vital for the development and utilization of deep mineral resources. However, it is always a challenging task to keep consistent wire rope tension in the event of an actuator fault. In this study, an adaptive dynamic surface technology-based actuator fault-tolerant scheme is proposed. A fault observer with a neural network adaptation term is designed to estimate the loss of actuator efficiency caused by faults. Considering the redundant characteristic of the two actuators, a novel dynamic surface technology-based controller with a fuzzy assignment and state constraints is developed to eliminate the impact of fault. The stability of the closed-loop system under the proposed strategy is theoretically proved by rigorous Lyapunov analysis. Comparative experiments under various conditions are carried out on a xPC based mine hoist platform, and the results show the applicability together with the superiority of the proposed scheme.

Design & Development of Electro Hydraulic Control Valve for Integration of Hoist and Steering System of a Dump Truck (35t)

The intent of this paper is to propose a system to control the steering operation and hoist operation of the Dump truck through combination of electro hydraulic valves and priority valve housed in Integrated manifold block. Electro hydraulic control valve(EHCV), and Electronic controller unit (ECU) for steering and hoist operation of the dump truck. The orbitrol valve consists of load sensing line, when the Orbitrol valve sense an effort on the steering wheel by the operator, the load sensing line will give a feedback signal to the electro hydraulic valve, which will divert the pressurized hydraulic oil to the steering system for steering operation, else the hydraulic oil is available for hoist operation. The hoist operation is control through Electronic Controller Unit (ECU). If there is no signal from the controller for hoist operation the hydraulic oil will flow back to tank. The Electronic controller will energize the combination of solenoid operated valves, depending upon the input received from operator through the momentary switch (Raise Switch, Lower/Float Switch, Hold Switch) mounted inside the cabin, which will allow the flow of pressurized hydraulic oil to the hoist cylinder for body raise and lower operation through electro hydraulic control valve. The electronic controller memorizes the signal from momentary switch and energizes the solenoids as per the logic till the next input signal receive by controller.

Piloted Simulation of the Rotorcraft Wind Turbine Wake Interaction during Hover and Transit Flights

Helicopters are used for offshore wind farms for maintenance and support flights. The number of helicopter operations is increasing with the expansion of offshore wind energy, which stresses the point that the current German regulations have not yet been validated through scientific analysis. A collaborative research project between DLR, the Technical University of Munich, the University of Stuttgart and the University of Tübingen has been conducted to examine the sizes of the flight corridors on offshore wind farms and the lateral safety clearance for helicopter hoist operations at offshore wind turbines. This paper details the results of piloted helicopter simulations in a realistic offshore wind farm scenario. The far-wake of rotating wind turbines and the near-wake of non-rotating wind turbines have been simulated with high-fidelity computational fluid dynamics under realistic turbulent inflow conditions. The resulting flow fields have been processed by superposition during piloted simulations in the research flight simulator AVES to examine the flight corridors in transit flights and the lateral safety clearance in hovering flights. The results suggest a sufficient size for the flight corridor and sufficient lateral safety clearance at the offshore wind turbines in the considered scenarios.

Statistical analysis of the durability of the hoist wireline and determination of its optimum reserve

Our work reports the results of a study investigating the durability hoist wireline and the determination of its optimum stock. Based on theoretical and experimental studies, is a regular 10...18 % decrease in the wirelines’ durability is reported at hoist operation in autumn-winter period in comparison to operation in spring-summer period. This should be considered when forming the optimum number of hoist wireline stocks to ensure effective operation throughout the year. The methodology developed by the authors for optimizing the stock of hoist wireline can lead to an increased economic efficiency due to reduced operating costs and increased efficiency of hoist operation.

An optimized variational mode decomposition method and its application in vibration signal analysis of bearings

The performance of the rolling bearing of a spindle device is directly related to the safety and reliability of the operation of a mine hoist. To extract bearing vibration signal features effectively for fault diagnosis, a feature extraction method based on the parameter optimization of a variational mode decomposition (VMD) method and permutation entropy (PE) is proposed. In addition, a support vector machine (SVM) classifier is used to identify bearing fault types. An analogue signal is used to test the effect of noise and sampling frequency on VMD performance. Focused on the problem of the VMD method needing to determine the number of mode components K and a penalty factor α during the signal decomposition process, a genetic algorithm is used to optimize the parameter combination [K,α] with the minimum sample entropy as the indicator. By using mean squared error (MSE) and correlation coefficient, an evaluation indicator is constructed to determine the decomposition effects of the optimized VMD, centre frequency, empirical mode decomposition (EMD) and ensemble EMD (EEMD) methods. The normalized PE of the five mode components is used as an eigenvalue, which is used as the input parameter of the SVM. Two different experimental datasets are used to verify the effectiveness of the proposed method. The results show that the proposed method has better diagnostic accuracy than EMD, EEMD and a BP neural network in the case of limited samples and unknown sample inputs. It can provide a good reference for the diagnosis of a rolling bearing and has practical application value.

Incidence and challenges of helicopter emergency medical service (HEMS) rescue missions with helicopter hoist operations: analysis of 11,228 daytime and nighttime missions in Switzerland

ObjectiveWe aimed to investigate the medical characteristics of helicopter hoist operations (HHO) in HEMS missions.MethodsWe designed a retrospective study evaluating all HHO and other human external cargo (HEC) missions performed by Swiss Air-Rescue (Rega) between January 1, 2010, and December 31, 2019.ResultsDuring the study period, 9,963 (88.7 %) HEMS missions with HHO and HEC were conducted during the day, and 1,265 (11.3 %) at night. Of the victims with time-critical injuries (NACA ≥ 4), 21.1 % (n = 400) reached the hospital within 60 min during the day, and 9.1 % (n = 18) at night. Nighttime missions, a trauma diagnosis, intubation on-site, and NACA Score ≥ 4 were independently and highly significantly associated with longer mission times (p < 0.001). The greatest proportion of patients who needed hoist or HEC operations in the course of the HEMS mission during the daytime sustained moderate injuries (NACA 3, n = 3,731, 37.5 %) while practicing recreational activities (n = 5,492, 55.1 %). In daytime HHO missions, the most common medical interventions performed were insertion of a peripheral intravenous access (n = 3,857, 38.7 %) and administration of analgesia (n = 3,121, 31.3 %).ConclusionsNearly 20 % of patients who needed to be evacuated by a hoist were severely injured, and complex and lifesaving medical interventions were necessary before the HHO procedure. Therefore, only adequately trained and experienced medical crew members should accompany HHO missions.

Helicopter Hoist Operations in Difficult Nonalpine Terrain

ObjectiveHelicopter hoist operations (HHOs) are an option for rescue in difficult- or impossible-to-access environments. At present, only a few helicopters in German helicopter emergency medical services have a hoist capability; most of them are located in the Bavarian Alps. We sought to study the demand for hoist operations in difficult terrain outside of alpine regions. MethodsThe setting for this study was a city borough between the Rhine valley and the Black Forest (Germany). We retrospectively studied all rescue operations in difficult terrain from January 1, 2007, to July 31, 2018. The characteristics of the terrain and operational, demographic, and medical aspects were analyzed. The predictors for a prolonged response time and the total prehospital time were identified by multivariate regression analysis. In addition, a simulation study creating time intervals for the alternative rescue procedure (ground vs. hoist) was performed. Operational data for the simulation were taken from an expert survey as well as field data collection in the course of HHO training. ResultsA total of 251 missions were included. Patients were predominantly male (66.7%) adults (57.5%) with traumatic lesions (75.0%); 14.1% had severe or multiple injuries, 4.7% had life-threatening medical conditions, and 4.3% were deceased. Two hundred eight patients (93%) were rescued by ground procedures. The prehospital time of HHO missions was significantly longer (104 vs. 72 minutes, P < .001). However, the simulation of all missions showed a significantly shorter prehospital time with 80 versus 91 minutes (P < .001) for rescue by HHOs. The predictors for prolonged prehospital times were a vague description of the accident site, difficult terrain, distance from the road, slope gradient, and life-threatening nontraumatic conditions of the patient. ConclusionWe found a significant benefit of hoist operations regarding the total prehospital time and admission to an appropriate trauma center. Consistent dispatch procedures for HHO missions can improve patient outcomes. Adding HHO capabilities to some selected helicopter emergency medical service helicopters should be considered.

Helicopter Hoist Performance in Novice and Experienced Hoist Operators.

BACKGROUND: Helicopter hoist operators are highly skilled and critical crewmembers in search and rescue. However, hoist operator training programs are relatively underdeveloped in comparison to helicopter pilot training. It is critical that this simulator teaches the necessary skills for high-level performance given the dangers associated with helicopter hoist operation. As a result, we sought to validate and identify critical aspects of skilled hoisting.METHODS: Through expert consultation, we identified several measures of hoist operation, such as mission time, cable plumb, cable tension, cable hand position, and cable displacement. We compared hoist performance between experienced and novice hoist operators in a simulated hoisting mission with two levels of difficulty (with and without wind). The experienced group (eight men/one woman) was composed of nine active or former military hoist operators who were working in commercial search and rescue. The novice group was composed of seven subjects (two men/five women) from the general population and had no previous experience with hoisting operations or the simulator.RESULTS: We found that experienced hoist operators had faster mission time, similar cable plumb, lower tension, and less variable hand position. Further, experienced hoist operators pulled the cable inward in the wind while novice hoist operators pushed the cable away.DISCUSSION: These findings suggests that this simulator captures performance differences between skill levels and, as a result, is a first step supporting the use of this simulator for hoist operator training.King MT, Lenser S, Rogers D, Carnahan H. Helicopter hoist performance in novice and experienced hoist operators. Aerosp Med Hum Perform. 2020; 91(6):496-500.

A Fault Diagnosis Method of Mine Hoist Disc Brake System Based on Machine Learning

The performance of the brake system is directly related to the safety and reliability of the mine hoist operation. Mining the useful fault information in the operation of a mine hoist brake system, analyzing the abnormal parts and causes of the equipment, and making accurate early prediction and diagnosis of hidden faults are of great significance to ensure the safe and stable operation of a mine hoist. This study presents a fault diagnosis method for hoist disc brake system based on machine learning. First, the monitoring system collects the information of the hoist brake system, extracts the fault features, and pretreats it by SPSS (Statistical Product and Service Solutions). This work provides data support for fault classification. Then, due to the complex structure of the hoist brake system, the relationship between the fault factors often has a significant impact on the fault. Considering the correlation between the fault samples and the attributes of each sample data, the C4.5 decision tree algorithm is improved by adding Kendall concordance coefficient, and the improved algorithm is used to train the sample data to get the decision tree classification model. Finally, the fault sample of the hoist brake system is trained to get the algorithm model, and then the fault diagnosis rules are generated. The state of the brake system is judged by classifying the data. Experiments show that the improved C4.5 decision tree algorithm takes the relativity of conditional attributes into account, has a higher diagnostic accuracy when processing more data, and has concise and clear fault classification rules, which can meet the needs of hoist fault diagnosis.

Examination the Influence of Human Factors in Indian Building Construction Sites

This research intends to explore the human factors which lead to non-fatal accidents (i.e. first aid case, near miss, lost time injury) and assessing safety supervision factors in building construction sites. A total of hundred non – fatal accident data is collected for the analysis. Human factors such as age, experience, language, education level and competency of the worker are explored using data analysis method. The root causes for the accidents are also determined and it is found that 22% of the construction site accidents are due to improper supervision. Furthermore a questionnaire survey is conducted among the Safety Engineers, Site Engineers, Supervisors and Workers to elicit the actual happenings about the safety supervision in the site. The questionnaire mainly focused on safety supervision factors and Relative Importance Index (RII) is used to rank the safety factors. As a result, monitoring hoist operation (0.73), moving vehicle (0.72) and checking the stability of scaffolds (0.69) shows higher level of disagreement which means that these factors have been given least priority. In order to measure the strength of relationship between the respondents, Spearman’s Rank Correlation is done. Through the Spearman’s correlation it is known that Safety Engineers vs Supervisors (0.83) and Safety Engineers vs Site Engineers (0.81) has high correlation values which indicates that these respondents have provided similar rankings.

Time Course of Hoist Operations by the Search and Rescue Helicopter Service in Southeast Norway

Optimal dispatch of emergency medical services relies on accurate time estimates of the various prehospital stages. Hoist rescue work time intervals performed by the search and rescue (SAR) helicopter service in Norway have not been studied to date. We aimed to describe the epidemiologic, operational, and medical aspects of the SAR service in southeast Norway. To complement the prehospital timeline, we performed simulated hoist operations. We reviewed time and patient descriptors and medical interventions in hoist operations performed at a SAR base over 5 y. In addition, a simulation study measuring hoist rescue time intervals was performed. Data are presented as mean±SD, except National Advisory Committee for Aeronautics (NACA) scores, which are presented as modes. There were 148 hoist operations performed during the study period, involving 180 patients. Time to take-off was 13±7 min. There were 88 patients (49%) who were injured; 53 (29%) had a medical condition, and 39 (22%) were evacuees. The mode of the NACA score was 3. Forty-five patients (25%) had an NACA score of 4 to 6. Medical interventions were performed on 77 patients (43%) in 73 operations (49%). Nine patients (5%) were endotracheally intubated, and 1 thoracostomy was performed. The simulated rescuer access time was 4±2 min, the simulated anesthesiologist access time was 6±2 min, and the simulated hoist extrication time was 13±2 min. Hoist rescue was performed in 10% (n=148) of the SAR operations. New information about hoist extrication time intervals can improve rescue helicopter dispatch accuracy.

Machine vision–based measurement approach for transverse vibrations of moving hoisting vertical ropes in mine hoists using edge location

Hoisting vertical rope is a continuum of one-dimensional movement during operation of hoist, and there are no appropriate ways to measure its vibration displacement at present. In this paper, a non-contact and unmarked machine vision measurement method is proposed for measuring the transverse vibration displacement of hoisting vertical ropes. First, we construct the background image to extract the ropes by the background difference method. Subsequently, a novel row-column data statistics filtering algorithm is proposed and applied to the edge detection image for removing the edges of the unmeasured rope. Finally, Hough transformation is used to locate the two edge lines at the boundary of rope and obtain the line parameters, which can be used to calculate the vibration displacement of the measured points at different times. The transverse vibration displacement of a moving hoisting vertical rope in a mine hoist was measured by using the reported machine vision measurement method, verifying the feasibility of the method. In order to verify the validity of the method, a simulation experimental system was built. The proposed method and the laser displacement sensor were used to measure the artificial transverse vibration displacement of a vertical rope simultaneously. The two results are in good consistency, which indicates that the proposed method can be fairly reasonable and accurate to measure the transverse vibration displacement of vertical rope in mine hoists.

Study on Dynamic Monitoring of Wire Rope Tension Based on the Particle Damping Sensor

Real-time monitoring of wire rope tension is of great significance to the safe operation of mine hoist. Due to the longitudinal and lateral coupling vibration of wire ropes during the operation of hoist, there are high frequency components in measured tension signals of wire ropes, which cannot effectively characterize the actual lifting load. To overcome this problem, a particle damping sensor with a vibration dissipation function is designed in this paper. Multilayered steel balls are placed into the cylindrical cavity of the sensor. Damping vibration and energy dissipation will occur when the sensor is subjected to external excitation. Then, to obtain the optimal sensor characteristics, relevant parameters of the particles and the spoke structure are simulated. Finally, the sensor based on the optimized parameters is manufactured and tested in a coal mine. Compared with the general pressure sensor, the particle damping sensor can effectively eliminate the influence of wire ropes vibration on tension measurement and achieve accurate measurement results.

Research on Dynamic Characteristics and Compensation of Wire Rope Tension and Load Measurement Based on Hydraulic Connection Device

During the operation of hoist, the speed and acceleration of each wire rope are inconsistent and the inertia force is changed due to the wear of the friction pad on the drum, which makes an impact on the cylinder of the tension balance hydraulic connection device and aggravates the flow pressure loss. It results in the nonlinear friction force between the piston and cylinder and affects the accuracy of wire rope tension and load measured by an oil pressure sensor which is installed on the tension balance hydraulic connecting device. In this paper, the simulation model of the tension balanced hydraulic connecting device is established by AMESim software, and the hydraulic dynamic response under different pressures, flow rates, and speed of a single hydraulic cylinder and tension balanced hydraulic connecting device is analyzed. The Leuven friction model is used to compensate the pressure loss along the course and local pressure loss and calculate the friction force, where specific parameters are determined by experiments. The real‐time compensation experiment of the tension balance hydraulic connecting device proves that the device effectively improves the accuracy of wire rope tension and load monitoring.