Handling Qualities Research Articles

Directional control law functional analysis and design for civil aircraft simulator

Abstract Functional analyses of directional flight control law for a typical civil aircraft are conducted, including directional maneuver, rudder limiter, coordinated turn, Yaw Damper, Thrust Asymmetrical Compensation, Gust Alleviation, manual rudder trim, etc. Through inputs of doublet, step input, and sweeping frequency, open loop control characteristics are analyzed based on a linearized state-space matrix. Simulink block architecture of a closed-loop directional control law is constructed, aiming to fulfill flight control functions, including pedal-to-rudder control, Yaw Damper, coordinated turn, and gain-tuned rudder limiter. Simulations for the previously designed closed-loop directional control law are performed to verify the characteristics of directional handling qualities in the aspect of the Yaw Damper, directional static and dynamic stability, maneuverability, and sweeping frequency.

Approach to Aircraft Handling Qualities Prediction

For the decades that followed the publication of the Cooper–Harper report that formalized a standard and universally recognized handling qualities pilot rating scale, researchers have sought to correlate pilot compensation—as well as physical and mental workload—with the assigned rating. A quantitative correlation remains elusive. In recent years, new physiological measurement devices have been developed that, together with software processing tools, can provide accurate measures of psychophysiological measures, including cognitive workload, distraction, and high/low engagement, based on electroencephalogram and electrocardiogram measures (i.e., brain waves and heart rate variability). The pilot compensation referred to in the Cooper–Harper scale is also a function of task performance measures that reflect aircraft characteristics and inceptor activity that reflects upon physical workload. Using a new piloted simulation test database generated in Manned Flight Simulator’s containerized rotary-wing simulator with 10 experienced test pilots, a machine-learning-based software algorithm that integrates a disparate mix of pilot–vehicle system, physiological, and task performance measures was used to further develop an approach to predict handling qualities levels and ratings.

Study on the evaluation method of pilot workload in eVTOL aircraft operation

This paper investigates the pilot control strategy and workload associated with the manned electric Vertical Take-Off and Landing (eVTOL) aircraft. This research aims to identify control strategies that are both rational and effective in reducing the pilot's workload. Although the Cooper-Harper rating (HQR, Handling Quality Rating) remains the prevalent benchmark for assessing pilot workload, its subjective nature often complicates the precise quantitative identification of the key factors influencing workload. This study introduces an assessment method for pilot control workload using wavelet transform to evaluate pilot workload, focusing on the correlation between pilot control magnitude, frequency components, and complexity. We begin with a review of control action analysis methods in both time and frequency domains. Subsequently, by selecting an appropriate wavelet function and a sampling frequency, we develop the assessment method for pilot control strategy and workload based on wavelet analysis. Finally, we assess pilot workload using real pilot inputs with HQRs obtained from helicopter flight tests and tilt-rotor aircraft conversion simulations. The results indicate that this approach is capable of precisely pinpointing the frequency components and energy levels within pilot control actions throughout different time periods. Furthermore, a significant correlation is observed between pilot control characteristics, frequency components, and HQRs. Consequently, the developed approach provides a rational framework for quantifying and analyzing pilot workload in a range of eVTOL aircraft scenarios.

Handling Qualities Assessment and Discussion for Helicopter with Slung Load Systems Utilizing Various Sling Configurations

Sling configurations significantly influence the coupled dynamics of the helicopter with slung load system (HSLS), resulting in alterations to handling qualities (HQs) that remain inadequately understood. This study introduces a computer-oriented, generalized method for constructing the HSLS model with various sling configurations. To evaluate the HQs of 1-point, 2-point, and 4-point sling configurations, both the stability and response criteria outlined in ADS-33E and a newly proposed criterion for slung loads towards the updated ADS-33F were employed. Modal analysis was conducted to elucidate the coupled mechanisms of the HSLS under different sling configurations. The findings reveal that the dynamics of the main rotor can attenuate the lateral swing motions of the load in the 4-point sling configuration. While multiple-point sling configurations can enhance the helicopter’s bandwidth, they also amplify the magnitude notch in the helicopter’s response. Nevertheless, when a larger hook distance is employed, the notch frequency is sufficiently distant from the load swing bandwidth, leading to a reduced degradation in HQs. A 4-point configuration with lateral and longitudinal hook distances equal to twice the width and length of the slung load is recommended in practice to achieve sufficient swing stability and mitigate HQ degradation.

Holographic visual cues for mission task elements

AbstractMission task elements (MTEs) are commonly used to evaluate the handling qualities (HQs) of rotorcraft. However, the traditional approach of physical ground courses faces challenges due to evolving rotorcraft designs and flight profiles. Infrastructure limitations and lack of flexibility for research pose significant obstacles, particularly for high-speed tasks. The emergence of new air vehicles, such as eVTOLs in the civil sector and future vertical lift configurations in the military domain, requires an adapted visual cueing process for previously unaddressed mission profiles. This paper proposes an innovative solution: an augmented reality (AR) system utilizing a head-mounted display to create virtual MTE courses called holographic visual cues (HVCs). A piloted simulation campaign performed at DLR’s AVES simulator compares the effectiveness of HVCs with dome projection-based visual cues, evaluating the performance of the AR system. The study investigated the impact of holographic visual cues on pilot handling qualities, workload ratings, and task performance, finding that although these cues typically do not significantly alter pilot ratings, individual responses varied, highlighting both the technology’s potential and the need for further refinement.

The Effect of Complaint Handling and Service Quality on Trust and Satisfaction of Dhyana Pura University Students

The Effect of Complaint Handling and Service Quality on Trust and Satisfaction of Dhyana Pura University Students

Current disease treatments for the ornamental pet fish trade and their associated problems

AbstractThe trade in live ornamental fishes to be held as companion animals or displayed in public aquaria has an estimated global annual value of US$15–20 billion. Supply chains for ornamental pet fishes often involve many more parties than for fish farmed as food fishes, and at each stage, fishes are exposed to stressors including handling, confinement, crowding, mechanical disturbance, and poor water quality. If chronic, these stressors can compromise their immune system, making fishes more susceptible to pathogens. Mortality and morbidity from infectious disease can result in considerable welfare impacts and massive economic losses for the industry, and the range of infective agents seen in ornamental species is well documented. However, treating these diseases is not straightforward with practices varying greatly across the trade and with several approaches having unintended consequences, such as the emergence of resistant strains of pathogens. While disease treatments for a handful of fish species (e.g., koi, goldfish) have received focused research attention, for the home aquarium owner, there is an increasing reliance on products based on natural compounds which have received far less scientific attention. This review aims to highlight the gaps in our knowledge surrounding the range of disease treatments used across the ornamental pet fish trade, with a particular focus on freshwater tropical species destined for home aquaria. Consideration is given to the potential problems arising from these treatments, including microbial resistance and effects of treatments themselves on fish health and welfare.

Helicopter augmented control laws for ship deck landing: HACLAS ONERA/DLR Joint Team

Different types of control laws are implemented, tested and compared for maritime operations particularly ship deck landing maneuvers at the flight simulation facilities at both DLR (German Aerospace Center) and ONERA (The French Aerospace Lab). At DLR, “classical” cyclic and collective stick flight controls were used during the piloted simulator trials while active side-sticks were operated at ONERA. A joint maritime scenario for ship deck landing in the simulation environments of both institutes is presented. Test methodologies and assessment techniques to evaluate the ship deck landings are harmonized based on different criteria such as quantitative measures and handling qualities (HQ) ratings to analyze the developed control laws. Simulation results based on pilot studies for an EC135 in the DLR simulator and an EC225 at ONERA are presented.

Analysis of Farmers' Knowledge Level of Off Season Cultivation Technology, Harvesting Techniques, Post Harvest Handling and Quality of Gedong Gincu Mango Fruits for the Export Market

Gedong gincu mango is a food commodity that has good added value with relatively high demand in various markets. Thus, production availability and quality standards can be realized by implementing off season gedong gincu mango cultivation, harvesting and post-harvest techniques that can minimize the level of losses due to improper handling. This research aims to determine the level of farmers' knowledge regarding off season cultivation, harvest techniques, post-harvest handling and fruit quality for the export market. The research was conducted in Sedong District with the consideration that this area is the highest mango production center in Cirebon Regency. The research is planned to be carried out in January 2024. The research design used is descriptive quantitative with survey research techniques. The sample in this study was 54 gedong gincu mango farmers. The data analysis technique was carried out using descriptive statistics with score weighting between 1 and 5. The results of the analysis showed that the level of knowledge of farmers in off season cultivation was 84.86%, harvest techniques were 82.90% and post-harvest handling was 82.04%. so it is classified as very knowledgeable, while farmers' knowledge of the quality of export fruit is 79.77%, so it is classified as knowledgeable.

Piloted Simulation-Based Assessment of Simplified Vehicle Operations for Urban Air Mobility

This work investigates the simplified vehicle operations paradigm, which seeks significant reductions in pilot workload and training requirements through the holistic design of flight control laws, control inceptors, and cockpit displays in the context of vertical takeoff and landing urban air mobility aircraft using piloted flight simulations. Two inceptor layouts, one similar to conventional fixed-wing aircraft and the other similar to conventional rotorcraft, differing in inceptor-to-command mappings, were incorporated into two research flight simulators. A lift-plus-cruise aircraft simulation model, a total energy control system–based fly-by-wire flight control architecture, and identical cockpit displays were used for both setups. Twenty-one participants, divided into three groups based on their prior piloting experience, were used to study pilot performance using representative handling qualities task elements. The piloted simulation data revealed that participants in each group were able to successfully perform the simulation tasks and allowed handling quality ratings to be calculated. They also highlighted instances of control coupling between inceptor axes in each setup for different tasks and the relative ease or difficulty of performing each task with the two inceptor designs.

Explicit Uncertainty Quantification for Probabilistic Assessment of Rotorcraft Handling Qualities

Early-stage vehicle design processes are typically subject to significant uncertainty in aerodynamic loads and control responses. In many cases, it may be necessary to consider this uncertainty in preliminary evaluations of stability, handling qualities, and performance metrics. This article introduces a novel methodology for computing these quantities in a probabilistic framework using the Koopman operator. The algorithm discretizes the uncertainty space and uses relevant transformations or simulations to map each point to the handling qualities evaluation domain, resulting in a stability, handling quality, and/or performance assessment for each discretized point. The expected value of the stability, handling quality, and/or performance requirement is then computed via quadrature integration, yielding a probabilistic assessment with respect to relevant specifications. The methodology is demonstrated through two examples involving a quadrotor unmanned aerial system and a generic utility helicopter. In the first example, the methodology is applied to evaluate the handling qualities of a quadrotor, for which a multiloop dynamic inversion controller is developed. In the second example, the method is used to quantify the impact of parametric uncertainty in a pilot model on specific pilot–vehicle system performance specifications and to predict vehicle handling qualities. The proposed explicit uncertainty quantification approach is shown to provide a convenient framework for the propagation of parametric uncertainty to stability, handling quality, and performance specifications with unique advantages over Monte Carlo techniques.

Influence of Engine Dynamic Characteristics on Helicopter Handling Quality in Hover and Low-Speed Forward Flight

This study assesses the influence of engine dynamic characteristics on helicopter handling quality during hover and low-speed forward flight. First, we construct the helicopter–engine coupling model (HECM) based on the power-matching relationship between the engine and the rotor. The impact of the engine is evaluated by comparing HECM with a helicopter model without the engine. To assess the engine’s influence quantitatively, we consider torque response, height response, and collective–yaw coupling characteristics in ADS-33E-PRF handling quality criteria. The results reveal that the engine power output lag can deteriorate the helicopter’s torque and height response handling quality rate (HQR). After the increase in helicopter mass, the torque HQR caused by engine influence improved, and the altitude HQR further deteriorated. The engine dynamic characteristics can also reverse the yaw rate, decreasing collective–yaw coupling HQR. As the helicopter’s flight speed increased, the engine’s impact on the yaw rate increased by 41.8%. This study can provide valuable insight into the effects of engine dynamic characteristics on helicopter handling quality and offer a reference for the design of helicopter–engine coupling control laws.

Milk Handling, Hygienic Practise and Microbial Qualities of Milk in Ethiopia

Milk Handling, Hygienic Practise and Microbial Qualities of Milk in Ethiopia

Advancing paediatric cardiac imaging: a comprehensive analysis of the feasibility and accuracy of a novel 3D paediatric transoesophageal probe.

Pediatric transoesophageal echocardiography (TOE) probes have remained two-dimensional (2D) limiting their use compared to adults. While critical in pediatrics for interventions and post-surgery assessments, technological advancements introduced a three-dimensional (3D) pediatric TOE probe. This study assessed the new 3D pediatric TOE probe (GE 9VT-D) for feasibility, handling, and imaging quality. At Children's Hospital of Toulouse, 2-month prospective study enrolled children undergoing TOE with the new probe. All imaging modalities were rated by 2 operators using a 5-point Likert-type scale from 1 (very poor) to 5 (very good) quality. Forty-five children, median age 3.7 (range: 2 months-14.7 years) median weight 7.8 kg (range: 4.3-48 kg) underwent 60 TOEs: 25% pre-surgery, 45% post-surgery, 28% during percutaneous procedures, and 2% in intensive care. Probe handling was "very easy" in all cases without adverse events. The median score of 2D, 2D colour, pulsed Doppler and 3D were noted 5 out of 5 and continuous Doppler and 3D colour 4 out of 5. The 3D image quality remained consistent irrespective of the patient weighing above or below 7.8 kg (p = 0.72). Postoperative TOEs identified two cases needing further interventions, emphasizing its value in evaluating surgical outcomes and also for guiding percutaneous interventions. Our comprehensive evaluation demonstrates that the new 3D pediatric TOE probe is feasible and provides high-quality imaging in pediatric patients. The successful integration of this novel probe into clinical practice has the potential to enhance diagnostic accuracy and procedural planning, ultimately optimizing patient outcomes in pediatric cardiac care.

Comparison of DNA extraction methods for COVID-19 host genetics studies.

The coronavirus disease 2019 (COVID-19) pandemic has resulted in global shortages in supplies for diagnostic tests, especially in the developing world. Risk factors for COVID-19 severity include pre-existing comorbidities, older age and male sex, but other variables are likely play a role in disease outcome. There is indeed increasing evidence that supports the role of host genetics in the predisposition to COVID-19 outcomes. The identification of genetic factors associated with the course of SARS-CoV-2 infections relies on DNA extraction methods. This study compared three DNA extraction methods (Chelex®100 resin, phenol-chloroform and the QIAamp DNA extraction kit) for COVID-19 host genetic studies using nasopharyngeal samples from patients. The methods were compared regarding number of required steps for execution, sample handling time, quality and quantity of the extracted material and application in genetic studies. The Chelex®100 method was found to be cheapest (33 and 13 times cheaper than the commercial kit and phenol-chloroform, respectively), give the highest DNA yield (306 and 69 times higher than the commercial kit and phenol-chloroform, respectively), with the least handling steps while providing adequate DNA quality for downstream applications. Together, our results show that the Chelex®100 resin is an inexpensive, safe, simple, fast, and suitable method for DNA extraction of nasopharyngeal samples from COVID-19 patients for genetics studies. This is particularly relevant in developing countries where cost and handling are critical steps in material processing.

Impact of Service Quality on Customer Satisfaction among Nepalese Cellular Mobile Service Providers

The objective of this study was to find out how satisfied customers are with Nepal Telecom and Ncell's mobile phone services. Both the analytical and the descriptive research designs were used in this study. All users of Nepal Telecom and Ncell mobile telephone services make up the study's population and 400 mobile telephone services user was considered as a sample of the study. In this study, correlation analysis was used to find the relationship between service quality factors and customer satisfaction and linear regression analysis was used to evaluate multiple independent variables that affect the dependent variables. The findings of this study depict that moderately positive correlation between tangibles, assurance, reliability, responsiveness, empathy, convenience, complaint handling, network quality, and customer satisfaction with mobile service providers. Similarly, the correlation is significant for tangibles, assurance, reliability, responsiveness, empathy, convenience, complaint handling, and network quality with customer satisfaction. This study also shows there was an insignificant impact of tangibles, reliability, responsiveness, convenience, complaint handling, and network quality of service quality on consumer satisfaction but an insignificant impact of assurance and empathy of service quality on consumer satisfaction among Nepalese cellular mobile service providers.

Exploring sound absorption properties of porous wood-based eco-friendly materials for noise reduction in buildings

In the last few years, there has been an increase in the use of eco-friendly materials in the area of acoustics made from natural fibers. These materials are preferable to synthetic materials because of their benefits, such as raw material availability, cost-effective processing costs, safe handling, and equivalent acoustic qualities. The main objective of this study is to find out how well the material made from vetiver grass absorbs sound. Following the International Standard ISO 354-2003 and ASTM 423-90, sound absorption tests were done in a reverberation chamber to find the Sound Absorption Coefficient (SAC) and Noise Reduction Coefficient (NRC) over a wide range of frequencies from 100–4000 Hz. To enhance the way the material absorbs noise, several ASTM E795-16 mountings were examined and tested. These mountings, which have air cavity sizes ranging from 0 mm (hard base) to 50, 100, and 300 mm, include J, E600, C50, D10, and C10. The most effective technique to enhance the material's acoustic qualities to lower noise was identified by comparing the SAC and NRC readings of samples with various-sized air gaps. The fitting of C10 with a SynthPF 10 × 50 back and a 50 mm air gap produced the best results (NRC 0.82). The produced porous pine boards with a density of 400 kg/m3 and a width of 20 mm met all the physical and mechanical property standards of the Indian Standards. The study shows that noise-absorbing materials made from vetiver grass could be used in buildings in ways that are better for the environment.

Improved Genetic Algorithm for Train Platform Rescheduling Under Train Arrival Delays

In this study, the train platform rescheduling problem (TPRP) at a high-speed railway station is analyzed. The adjustments of the train track assignment and train arrival/departure times under train arrival delays are addressed in the TPRP. The problem is formulated as a mixed-integer nonlinear programming model that minimizes the weighted sum of total train delays and rescheduling costs. An improved genetic algorithm (GA) is proposed, and the individual is represented as a platform track assignment and train departure priority, which is a mixed encoding scheme with integers and permutations. The individual is decoded into a feasible schedule comprising the platform track assignment and arrival/departure times of trains using a rule-based method for conflict resolution in the platform tracks and arrival/departure routes. The proposed GA is compared with state-of-the-art evolutionary algorithms. The experimental results confirm the superiority of the GA, which uses the mixed encoding and rule-based decoding, in terms of constraint handling and solution quality.

Nicotinamide-based agglomerates of ibuprofen: formulation, solid state characterization and evaluation of tableting performance with in-silico investigation

BackgroundThe objective of the present investigation was to obtain directly compressible agglomerates of ibuprofen with nicotinamide by a quasi-emulsification solvent diffusion technique. Ibuprofen-nicotinamide agglomerates were prepared by quasi-emulsification solvent diffusion technique using ethanol (good solvent), water (poor solvent), and chloroform (bridging liquid). The prepared agglomerates were characterized by ATR-FTIR, powder X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy and were evaluated for tableting performance and in vitro drug release. To appropriately identify the hydrogen bonding sites, a thorough understanding of the structures of API and coformer is necessary, hence molecular docking approach was implemented to depict the interaction between the proposed coformer and COX-2 protein (PDB Id:4PH9).ResultsThe percent yield of agglomerates was in the range of 85–98 w/w%, and drug content for all batches was in the range of 96–99%. The microphotographs showed irregular circularly shaped agglomerates. ATR-FTIR study showed a strong possibility of hydrogen bonding between ibuprofen and nicotinamide. The crystallinity of ibuprofen was slightly reduced and confirmed by P-XRD and DSC. Crushing strength and friability studies showed good handling qualities of ibuprofen agglomerates. Heckel plot studies showed low mean yield pressure and high tensile strength, indicating excellent compressibility and compactibility of ibuprofen agglomerates. More than 90% drug release was obtained within 60 min in PBS (pH 7.4). The docking studies revealed that nicotinamide individually has –CDOCKER energy 16.8109 where coformer showed 29.0584, which indicates coformer has a better binding affinity to target as compared to nicotinamide individual.ConclusionsIt can be concluded that the agglomerates improved the dissolution, tableting performance, and solid-state properties of ibuprofen and hence can be useful to improve the therapeutic performance of ibuprofen.Graphic

Design Modification of Mechanical Flight Control Circuits of an Intermediate Aerobatic Trainer Aircraft for Improved Efficiency

In a typical Intermediate Aerobatic Trainer Aircraft (IATA) the primary control surfaces viz, Ailerons, Elevator and Rudder are operated mechanically and thus called Mechanical Flight Control System (MFCS) consisting of elements such as push-pull rods, levers, torque tubes etc. Design considerations for such MFCS include strength, stiffness, ergonomics, low circuit friction, kinematic feasibility etc. During the developmental flight trials, in one of the prototype aircraft, it was found that full control surface movement was not achieved under maximum aerodynamic load. This led to the reduction in efficiency of the system. Based on the analytical calculations and Finite Elemental (FE) simulations, it was found that considerable elastic deformation of mechanical elements as well as support structure had lowered the efficiency which was also validated experimentally. Although, aircraft handling qualities were found to be satisfactory during the normal flight testing, it was desirable to improve the efficiency of the MFCS. This paper broadly outlines the methodologies adopted to improve the efficiency of the existing control circuits considering aero-elasticity and structural design aspects