A.C. in 't Veld
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1
Preventing Loss of Control In-flight (LOC-I) in commercial and general aviation is an active research area with numerous proposed solutions. One of these solutions aims to prevent lateral LOC-I, a special type of LOC-I, by presenting a roll-performance based minimum lateral control speed to the pilot in roll-limited situations, such as single-engine failure scenarios in multi-engine aircraft. This minimum lateral control speed is predicted by a system, named the Vc Prediction System (VPS), which continually predicts the minimum lateral control speed Vc at which an aircraft can still obtain a certain roll angle within a certain amount of time. It consists of three components; a linear model, a parameter estimation method and a Vc prediction model. These VPS components were designed for a simulation model of the Piper Seneca. This study analyzes the sensitivity of the VPS design to a change in aircraft dynamics and simulation model complexity by redesigning this system for a high-fidelity simulation model of the Fokker 50. The results show that both aircraft favor a small linear model and the Modified Kalman Method for parameter estimation. The original Vc prediction model however gives higher Vc prediction errors for the Fokker 50 than for the Piper Seneca. By simplifying the original Vc prediction model a stable, smooth and relatively accurate Vc prediction for the Fokker 50 can be obtained.
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Preventing Loss of Control In-flight (LOC-I) in commercial and general aviation is an active research area with numerous proposed solutions. One of these solutions aims to prevent lateral LOC-I, a special type of LOC-I, by presenting a roll-performance based minimum lateral control speed to the pilot in roll-limited situations, such as single-engine failure scenarios in multi-engine aircraft. This minimum lateral control speed is predicted by a system, named the Vc Prediction System (VPS), which continually predicts the minimum lateral control speed Vc at which an aircraft can still obtain a certain roll angle within a certain amount of time. It consists of three components; a linear model, a parameter estimation method and a Vc prediction model. These VPS components were designed for a simulation model of the Piper Seneca. This study analyzes the sensitivity of the VPS design to a change in aircraft dynamics and simulation model complexity by redesigning this system for a high-fidelity simulation model of the Fokker 50. The results show that both aircraft favor a small linear model and the Modified Kalman Method for parameter estimation. The original Vc prediction model however gives higher Vc prediction errors for the Fokker 50 than for the Piper Seneca. By simplifying the original Vc prediction model a stable, smooth and relatively accurate Vc prediction for the Fokker 50 can be obtained.
Conference paper
(2023)
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V.G. Vasilopoulos, C. Borst, M.M. van Paassen, A.C. in 't Veld, Max Mulder
The Continuous Descent Approach (CDA) offers reduced aircraft noise emissions and fuel consumption, but the obstacle limiting it to reduced traffic density conditions, is the low predictability of the trajectory and Estimated Time of Arrival (ETA). The solution proposed by this research is to develop a pilot support interface to facilitate the execution of a fixed flight path angle CDA, where thrust is not limited to idle and a velocity profile can be tracked, which will lead to a selected ETA. Initially, the CDA trajectory was investigated through an aerodynamic model, while the solution space of the ETA and the calculation of the stepwise velocity profile were defined. Following the analysis of the pilot’s role, a two-fold support interface was designed based on Ecological Interface Design (EID), with a Vertical Situation Display (VSD) playing a central role for planning and execution. The interface was tested in a MATLAB®/Simulink® setup and five pilots were recruited to execute simulations over different wind conditions. Their on-time performance was satisfactory, while they worked with the provided cues and suggested some interface changes to offer more flexibility. A more robust application of the proposed approach can lead to a wider adoption of the CDA, as a validated procedure.
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The Continuous Descent Approach (CDA) offers reduced aircraft noise emissions and fuel consumption, but the obstacle limiting it to reduced traffic density conditions, is the low predictability of the trajectory and Estimated Time of Arrival (ETA). The solution proposed by this research is to develop a pilot support interface to facilitate the execution of a fixed flight path angle CDA, where thrust is not limited to idle and a velocity profile can be tracked, which will lead to a selected ETA. Initially, the CDA trajectory was investigated through an aerodynamic model, while the solution space of the ETA and the calculation of the stepwise velocity profile were defined. Following the analysis of the pilot’s role, a two-fold support interface was designed based on Ecological Interface Design (EID), with a Vertical Situation Display (VSD) playing a central role for planning and execution. The interface was tested in a MATLAB®/Simulink® setup and five pilots were recruited to execute simulations over different wind conditions. Their on-time performance was satisfactory, while they worked with the provided cues and suggested some interface changes to offer more flexibility. A more robust application of the proposed approach can lead to a wider adoption of the CDA, as a validated procedure.
The Delft University laboratory aircraft Cessna Citation II has the capability to implement and test new auto pilot control laws. The aircraft is equipped as a Fly-By-Wire testbed, that enables the user to control the aircraft through an experimental computer and directly have control over the control surfaces. An extra control stick is mounted on the righthand side in the cockpit from where the aircraft can be controlled in a closed loop. The gains can be adjusted in-flight. An experimental display in the cockpit showed the setpoints for the rate and direct control in pitch and roll.
The control laws that were tested are developed by the department of aircraft systems dynamics of the German Aerospace Center together with Delft University of Technology. The control laws are based on Incremental Nonlinear Dynamic Inversion (INDI). INDI uses synchronized measurements or estimations of (angular) accelerations and control surface deflections. This way it is not dependent on an airplane model, but it is able to automatically adapt flight control laws to changing dynamic behavior of the aircraft, even in case of major system failures or damage to the airframe. The INDI controller directly controls the current to the control surface actuators.
This paper treats the execution of the test flights.
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The control laws that were tested are developed by the department of aircraft systems dynamics of the German Aerospace Center together with Delft University of Technology. The control laws are based on Incremental Nonlinear Dynamic Inversion (INDI). INDI uses synchronized measurements or estimations of (angular) accelerations and control surface deflections. This way it is not dependent on an airplane model, but it is able to automatically adapt flight control laws to changing dynamic behavior of the aircraft, even in case of major system failures or damage to the airframe. The INDI controller directly controls the current to the control surface actuators.
This paper treats the execution of the test flights.
...
The Delft University laboratory aircraft Cessna Citation II has the capability to implement and test new auto pilot control laws. The aircraft is equipped as a Fly-By-Wire testbed, that enables the user to control the aircraft through an experimental computer and directly have control over the control surfaces. An extra control stick is mounted on the righthand side in the cockpit from where the aircraft can be controlled in a closed loop. The gains can be adjusted in-flight. An experimental display in the cockpit showed the setpoints for the rate and direct control in pitch and roll.
The control laws that were tested are developed by the department of aircraft systems dynamics of the German Aerospace Center together with Delft University of Technology. The control laws are based on Incremental Nonlinear Dynamic Inversion (INDI). INDI uses synchronized measurements or estimations of (angular) accelerations and control surface deflections. This way it is not dependent on an airplane model, but it is able to automatically adapt flight control laws to changing dynamic behavior of the aircraft, even in case of major system failures or damage to the airframe. The INDI controller directly controls the current to the control surface actuators.
This paper treats the execution of the test flights.
The control laws that were tested are developed by the department of aircraft systems dynamics of the German Aerospace Center together with Delft University of Technology. The control laws are based on Incremental Nonlinear Dynamic Inversion (INDI). INDI uses synchronized measurements or estimations of (angular) accelerations and control surface deflections. This way it is not dependent on an airplane model, but it is able to automatically adapt flight control laws to changing dynamic behavior of the aircraft, even in case of major system failures or damage to the airframe. The INDI controller directly controls the current to the control surface actuators.
This paper treats the execution of the test flights.
Conference paper
(2016)
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N de Gelder, F. J L Bussink, E. G. Knapen, A.C. in 't Veld
For the Schiphol terminal airspace, a new handling concept is developed with fixed arrival routes and continuous descent approaches. The aviation sector agrees that fixed arrival routes are desired from the TMA boundary to the runway related to predictability and enabling continuous descent approaches. Fixed arrival routes however have the tendency to negatively affect capacity and Schiphol can afford no loss of capacity. Therefore, research is done for innovative ways to handle the incoming traffic, to make high capacity combined with fixed arrival routes possible. Interval Management (IM) is seen as one of the promising innovations to support the new handling concept at Schiphol. With IM, aircraft exchange flight information via ADS-B and use this information to control an ATC assigned time interval with a lead aircraft. It is assumed that this close loop control provides the accuracy and predictability that is required to maintain peak hour capacity. The KDC IM research involves a number of phases. In the first phase requirements were captured. During the second phase fast-time simulations were performed to evaluate the spacing performance. The outcome of these simulations is positive: IM can generate the required performance in the Schiphol terminal environment, allowing high-density operations on fixed routes with continuous descents. The third phase progressed with IM real-time simulations (RTS) to assess controller acceptance and workload and to evaluate the IM procedures and IM support tools. The main results of the RTS are: - All controllers readily accepted and appreciated the IM Concept of Operations and were able to safely and efficiently manage the arrival traffic in all scenarios, including non-normal events, with the newly developed HMI. - Perceived controller workload was generally well within predefined targets in all scenarios. - The average number of R/T instructions per aircraft did not vary much between IM and non-IM operations. - The percentage of (unanticipated) IM cancellations by the controller was very low (<3%).
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For the Schiphol terminal airspace, a new handling concept is developed with fixed arrival routes and continuous descent approaches. The aviation sector agrees that fixed arrival routes are desired from the TMA boundary to the runway related to predictability and enabling continuous descent approaches. Fixed arrival routes however have the tendency to negatively affect capacity and Schiphol can afford no loss of capacity. Therefore, research is done for innovative ways to handle the incoming traffic, to make high capacity combined with fixed arrival routes possible. Interval Management (IM) is seen as one of the promising innovations to support the new handling concept at Schiphol. With IM, aircraft exchange flight information via ADS-B and use this information to control an ATC assigned time interval with a lead aircraft. It is assumed that this close loop control provides the accuracy and predictability that is required to maintain peak hour capacity. The KDC IM research involves a number of phases. In the first phase requirements were captured. During the second phase fast-time simulations were performed to evaluate the spacing performance. The outcome of these simulations is positive: IM can generate the required performance in the Schiphol terminal environment, allowing high-density operations on fixed routes with continuous descents. The third phase progressed with IM real-time simulations (RTS) to assess controller acceptance and workload and to evaluate the IM procedures and IM support tools. The main results of the RTS are: - All controllers readily accepted and appreciated the IM Concept of Operations and were able to safely and efficiently manage the arrival traffic in all scenarios, including non-normal events, with the newly developed HMI. - Perceived controller workload was generally well within predefined targets in all scenarios. - The average number of R/T instructions per aircraft did not vary much between IM and non-IM operations. - The percentage of (unanticipated) IM cancellations by the controller was very low (<3%).