Browse Topic: Human factors
As part of a human factors research project aimed at optimizing technical documentation used in helicopter maintenance with multimedia elements, we compared different instruction formats to observe their effects on the performance of an assembly task. This task offers us the opportunity to test procedures that call for similar actions as a maintenance task (e.g., localization, action sequencing, assembly). Static (i.e., image and image with text) and dynamic instruction formats (i.e., video, video with text and video with audio) were compared to determine if dynamic formats allowed a better motor performance of the task for assembly reaction time (time needed to complete the assembly) and accuracy. We were also interested in how the use of the text instructions interacted with both visual dynamic and static instructions. Reaction times were recorded and measured with eye tracking data. Subjective data was collected in questionnaires during and after the experiment. Results showed significant differences in the time spent on the instructions and the time spent on the assembly, depending on the format of instructions. Overall, assembly time is shorter with video instruction formats, but videos took longer to be consulted than static formats. Results also showed a difference in the number of actions required to do the assembly. Videos facilitated the right path of action sequence in comparison with static formats. With the analysis of both subjective and objective data, the results give us a better idea of the advantages and drawbacks of using dynamic formats in technical documentation.
The development of an adaptive pilot model for rotorcraft tracking tasks is useful to understand and replicate human pilot behavior under varying vehicle dynamics and environmental conditions. This paper presents a Model-Reference Adaptive Control (MRAC)-based pilot model designed to emulate the adaptability of human pilots during attitude and position tracking tasks. The model leverages wavelet analysis to characterize pilot behavior and employs a closed-loop system identification approach to derive baseline pilot parameters. MRAC methodology using state-feedback is implemented and validated through simulations involving time-varying vehicle dynamics, such as changes in control sensitivity and added phase delays. Results demonstrate the model's ability to maintain consistent tracking performance despite dynamic modifications, though discrepancies with human pilot data highlight the complexity of fully capturing adaptive human control strategies. The proposed model offers a framework for integrating human adaptability into flight system design and simulation tools.
ABSTRACT Shipboard operations present a unique set of challenges to the pilot-vehicle system. This work addresses problems specific to piloted rotorcraft in the simulated shipboard environment, namely cueing and ship motion, and represents the completion of a three-year effort focused on fixed-base, pilot-in-the-loop rotorcraft flight simulations. Instructors from the United States Naval Test Pilot School, with extensive operational and test experience, participated in the study. Two cueing sets, one for the approach task and another for the hover task, were developed in order to provide intuitive guidance of cyclic and collective inputs. Data were gathered for each task with the cueing system both on and off. The evaluation criteria used to determine the usefulness of the provided cueing were based on pilot workload assessment, profile performance and inceptor activity. The approach task cueing provides the pilot with a preset approach profile defined by altitude and airspeed cueing, while the hover task cueing provides the pilot with a top-down view of helicopter position over the landing spot and a representation of the vehicle’s acceleration vector. Different control response types were assessed, as well as different ship motion intensities. Both tasks show that use of the developed cues allows pilots to achieve greater precision with less overall workload when compared to task performance without cueing available.
This paper examines the Handling Quality Rating (HQR) of the Model-Based Pilot Controller (MBPC) in failure scenarios within the Automatic Flight Control System (AFCS). The MBPC aims to automate the testing of malfunctions in the AFCS of the T625 Gökbey platform. It is constructed using optimal control and estimation theory, with the cost function representing human characteristics determined by weighting matrices. The optimal values of weighting matrices that minimize the cost function are achieved via Genetic Algorithm. This algorithm utilized to systematically minimize user-defined cost functions tailored to optimize performance for selected maneuvers within the scope of ADS33E-PRF, considering user-defined constraints. Time-domain metric performance is provided for two maneuvers: vertical maneuver and hovering turn. The HQRs of the MBPC evaluated according to Power Frequency and Inceptor Peak Power-Phase (IPPP) metrics. The MBPC satisfies the ADS33 desired performance criteria in case of a failure scenario in AFCS throughout the maneuver, achieving satisfactory handling quality results.
Piloted simulation has been used for decades to support flight test activities at the Naval Air Warfare Center Aircraft Division located at Naval Air Station Patuxent River, MD. Conventional lab stations at the Manned Flight Simulator facility have been used effectively to support a wide range of flight test requirements. However, there were limitations with these conventional lab stations when the purpose was to assess handling qualities and pilot workload while landing rotorcraft aboard a ship. Two critical simulation elements were determined to be necessary: (1) an expanded field of view so the pilot could see the ship deck below the aircraft and (2) a motion system to provide the pilot with vital proprioceptive cueing in the turbulent ship environment. A new Virtual Reality Lab was developed at Patuxent River that included these key features. The primary components of the lab included virtual reality headsets, an Unreal Engine image generator, ocean and ship visual models, a six degree-of-freedom motion platform, and a generic cockpit. This paper describes development of the lab, various issues that were encountered, and plans for future improvements.
ABSTRACT Rotorcraft shipboard landing continues to be challenging due to increased pilot workload in dealing with effects of ship air wake turbulence on vehicle motion and random ship motion. Some of the recent work has proposed a pilot assist function for reduced pilot workload using model predictive control methods. This paper explores the use of a recently developed Model Predictive Path Integral (MPPI) method based on a stochastic optimal control framework for trajectory guidance solution to the shipboard landing problem. First, a proof-of-concept study is presented by applying the MPPI method to a simple point mass approximation of helicopter dynamics represented in the form of a first-order command acceleration model, representative of helicopter trajectory motion in the vertical plane. Next, the MPPI method is used in conjunction with a six degrees-of-freedom linear model of a helicopter in order to gain further insight into the applicability of the MPPI framework to the rotorcraft shipboard landing problem. The paper concludes with key observations and inferences gained in this study.
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Helicopter shipboard launch and recovery are some of the most challenging operations to date, owing to the pilot workload associated with the tasks. A variety of environmental conditions such as random deck motion, heavy sea states and unsteady aerodynamic interactions can be attributed to the same. This paper highlights the development and assessment of a visual flight lead cue for real-time guidance and pilot workload reduction. For a chosen approach-turnland maneuver, the pilot workload is assessed using data from pilot-in-the-loop (PIL) flight simulations. Quantitative metrics based on Time-Frequency Representation (TFR) are used to evaluate pilot workload and the analysis of workload in the presence and absence of the cue is presented. Furthermore, the deviations from the desired path are studied using root-mean-square error (RMSE) for the cue on/off cases. The relation between pilot workload and path following is analyzed to determine the efficacy of the cue provided.
Collins Aerospace, through its Common Avionics Architecture System (CAAS) and Flight2 avionics management systems for rotary wing aircrafts, provides extensive video processing, internal graphics generation, and overlay capabilities on real time video streamed from onboard EO/IR cameras providing situational awareness to the pilot in clear day-light and reduced visibility/night conditions. This capability has served our customers well in their cargo, assault, and multi-mission roles, improving the effectiveness of their missions. We now realize that more can be done to reduce pilot workload and enhance mission effectiveness by extracting visual intelligence from the video feed using machine vision. In this paper we explore the use of deep learning based computer vision to extract visual intelligence from onboard video feed and use it to automate low risk pilot actions, such as automatic detection and tracking of objects of interest, panning to maintain focus on objects, zooming on to a chosen object and providing contextualized data link message recommendations.
A core mission of the CH-53K involves flying in severe brownout conditions, which increases pilot workload and can reduce mission success rates. With state of the art Fly by Wire capability, the CH-53K leverages the computational power of a flight control computer to provide higher order control modes which reduce pilot workload in all degraded visual environments such as brownout. The preliminary design of the flight control system included the inceptor system and low speed control architecture, which created an expansive design space. High fidelity simulations, cockpit mockup, and use of the NRC Bell 412 in-flight simulation Advanced Systems Research Aircraft surrogate aircraft allowed for a comprehensive development environment to narrow down to final control system design. The final design of the low speed maneuvering provided a command strategy similar to translational rate commend yet provided an approach profile that more closely replicated a piloted approach to a landing zone in DVE. This paper provides details of the system design along with initial results from flight test.
Successful human intervention will be central to any emerging autonomous aerial transport platform, such as personal aerial vehicles (PAV), for the safe conduct of flight. This paper proposes a concept to compensate a partial failure of the autonomous flight guidance by handing over control of the aircraft to a passenger and analyzes the associated human factors. First, a novel waypoint guidance law is designed that generates the desired roll commands for navigation to a designated safe landing spot. Second, two novel guidance display concepts are developed, one for the primary flight display (PFD), and another for the helmet mounted display (HMD), which indicate the desired roll commanded by the guidance law. Third, the guidance law and display concepts are integrated into a high-fidelity, wide field-of-view flight simulation environment and a static mock-up of a conventional helicopter cockpit. Humanin-the-loop experiments were performed with test subjects to analyze the effectiveness of the guidance law and display concepts, and to evaluate piloting performance by non-professional pilots. Various mission task elements were analyzed in these experiments and, in order to intensify workload, a disturbance was included together with a guidance law for commanded roll of PAV. Navigation performance, test subjects' ratings and workload are measured by a combination of objective and subjective analyses. Results indicate that all test subjects were able to reach a close vicinity of the landing spot. Furthermore, the HMD concept shows a lower workload with equal or better navigation performance when compared to the PFD concept.
This paper describes the development of full flight envelope dynamic inversion outer-loop control laws used to control airspeed and flight path for two Future Vertical Lift-relevant rotorcraft configurations - a lift offset coaxial helicopter with a pusher propeller and a tiltrotor. The outer-loop control laws for both aircraft include a control allocation scheme to account for redundant controls and reduce pilot workload. A piloted simulation experiment was conducted at the Penn State Flight Simulator facility using a series of high-speed handling qualities demonstration maneuvers to evaluate the handling qualities of the control laws. Overall, the outer-loop control laws for both coaxial-pusher and tiltrotor aircraft were assigned Level 1 handling qualities for the Break Turn and High-Speed Acceleration/Deceleration tasks, and reduced pilot workload over previously developed inner-loop control laws. The outer-loop control laws also improved performance and reduced pilot workload in a formation flying task developed for this experiment. The coaxial-pusher outer-loop control laws received borderline Level 1/Level 2 ratings for the Pitch Attitude Capture and Hold and Sum-of-Sines Tracking tasks, while the tiltrotor outer-loop control laws (with their increased value of pitch attitude dropback) received Level 2 ratings.
The benefits of developing objective measures of handling qualities, more specifically pilot workload, are of great interest to the United States Navy. Several lines of research have been initiated to that end with this study focusing on inceptor activity. Potential pilot inceptor workload metrics were applied to a data set consisting of ten pilots conducting simulated approach and hover tasks to a DDG-class ship. Piloted handling qualities ratings were recorded for the tasks. Workload variation was induced by using different aircraft response types, varying degrees of ship motion, and the presence/absence of cueing. Using only pilot inceptor state data, potential workload metrics were evaluated and correlations with handling qualities ratings were examined. Methods to apply traditionally single-axis metrics to multi-axis tasks were explored, inconclusively. Predictive ability of the simple metrics improved by breaking tasks into pseudo-time invariant sub-tasks. A multi-axis metric from past research was shown to correlate best with workload ratings, but several more traditional workload measures show promise and correlation may improve if applied to a scale other than Cooper-Harper. A novel approach of treating the multi-axis problem as a metric itself is introduced and data presented to support adoption as a workload discriminator in and of itself.
Autorotation is a challenging maneuver during which pilot workload is high. Consequences of an improperly performed maneuver are potentially catastrophic, thus partial automation and/or pilot cueing can potentially be used to reduce pilot workload and increase the probability of a successful landing. This paper describes the development of a nonlinear model predictive control (MPC) scheme and a trajectory generation method that can be used to perform autorotations autonomously, or in development of pilot aids. The proposed control scheme offers potential benefits over existing methods by balancing simultaneous control objectives of trajectory tracking and rotor speed regulation. Results are presented for a six-degree-of-freedom simulation of the AH-1G aircraft. The results are compared to a traditional cascaded PID control scheme to demonstrate the benefits of the MPC algorithm. A trade study is presented in which the target landing point is varied to quantify the benefits of the MPC over a range of landing profiles.
This work examines the handling qualities (HQ) rating scale from a psychophysical perspective, characterizing workload as the response to a stimulus composed of input to the pilot and pilot outputs. Previous work by the author examining three different display tracking tasks indicated that pilot workload is effectively a logarithmic function of tracking error rate and control rate. This approach, called the Spare Capacity OPerations Estimator (SCOPE), is extended to flight and Handling Qualities data collected (109 runs) for the slalom Mission Task Element (MTE) using the U.S. Army’s JUH-60A RASCAL aircraft. Attitude and Rate Command response types as well as various forcefeel configurations were tested. Based on flight data observation a novel and intuitive action model is proposed for the slalom MTE whereby the pilot operates on the relative angle between the ground track and the upcoming cone’s location (effectively the cone’s location on the windscreen relative to the aircraft nose, assuming a no-wind environment). Proximity to an approaching cone determines which of two strategies is active: maintaining a constant relative angle or maintaining the relative angular rate constant. A method is proposed for mapping Handling Qualities (HQ) ratings to flight data performance and the workload estimate, offering the possibility for easing the requirement that a pilot trained in HQ evaluation fly test maneuvers. Applying this approach to the slalom maneuver produced good correlation between actual and estimated HQ ratings over the varying aircraft and inceptor feel system dynamics.
This paper presents preliminary results of a pilot-in-the-loop (PIL) study of different cueing designs to reduce pilot workload in rotorcraft shipboard landings. The participants were tasked with flying an approach to touchdown on the deck of an Arleigh Burke Flight IIA class Destroyer under both day visual flight rules (VFR) and night-unaided, zeroillumination conditions. For each condition, the participants were presented with three different cue types. For the day iterations these were a generic military standard heads up display (HUD), a ship fixed tunnel in the sky (tunnel), and a virtual flight lead cueing system (FLCS). The zero-illumination night condition was deemed impossible to land with only the HUD, so it was replaced with a combination of the tunnel and FLCS for the purpose of gaining initial feedback on combining elements of different systems. Terminal landing constraints (location, heading, and impact velocity) were used as measures of pilot performance, the NASA Task Load Index (TLX) survey was used to evaluate perceived pilot workload, and the System Usability Scale (SUS) was used to rate interface and cueing usability. Initial findings showed that pilots viewed the tunnel cueing as having the lowest perceived workload while the FLCS provided the best terminal performance. All types of 3D cueing improved performance when compared to the HUD baseline. The use of 3D cueing also expanded the operational envelope to include zero-illumination conditions. For completeness, the study requires additional subjects, specifically those that have prior shipboard landing experience, as COVID-19 safety precautions paused in-person simulator testing early in the testing period. This body of work represents the next iteration of FLCS research, initially published in Ref. 1.
The National Research Council of Canada and Université de Sherbrooke performed flight testing of an Actively Stabilized Slung Load on the NRC Bell 206 Research Aircraft. Hover, Attitude Capture, NRC designed Lateral Precision Hover, and Frequency Sweep mission tasks were performed for bare airframe and slung load aircraft configurations. The load mass ratio was 0.12 while the slung load pendulum mode was 1.3 rad/sec at a damping ratio of 0.2 for the 40-pound per active tether saturation load system setting. Time domain response indicated that the load remained controllable with damped and underdamped behaviors. Frequency domain analyses confirmed pilot comments indicating HQR 4 handling qualities ratings for bare airframe and stable slung load behavior. This rating degraded to HQR 5 for task execution with slung load oscillation. Pilot workload was due to lateral cycle input requirements of 2 to 3 inch amplitudes at 1 to 2 Hz frequency. Operationally, the coincidence of pilot inputs with active tether induced airframe and short period modes led to high compensation requirements for lateral axis tasks under study. The complexity of active tether management, an actuator failure, and telemetry faults represented system deficiencies. Comparable bare airframe and slung load configuration task execution results indicate the magneto-rheological actuation system’s potential to improve slung load mission task performance.
The advent of the COVID-19 pandemic has created uncertainty and delays in procedures, but hospitals and surgeons still need a steady supply of product, meaning that the orthopedics industry must keep innovating. One thing is certain, 2020 will be a turbulent year for procedure demand. Early on, analysts predicted that because many orthopedic procedures are elective, they would be postponed to help free up space for critically ill patients. While the recovery of orthopedic procedures has begun more quickly than analysts initially expected, it seems likely it will take longer than expected to reach full recovery as we look into 2021. June ordering patterns were already much higher than May, but the quicker recovery may indicate a second decline (W-shaped) versus a sharp decline followed by a quick recovery (V-shaped).
Over the years, technological innovation has allowed the medical equipment sector to become a mission-critical part of the healthcare industry, delivering such benefits as lower operating costs and improved patient outcomes. But competitive pressures are driving the need for device developers to provide a richer experience for users, incorporating broader capabilities and features and more options.
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