Language：English   Publishing type：Research paper (other academic)  

In this paper, the equilibrium orientations of magnetically suspended platforms that are statically loaded and constrained to 2 degrees of freedom are analyzed. It is shown that under these conditions, a symmetric, 2-magnet system can have a maximum of two equilibrium orientations for a given force-moment load. Further, it is shown that these two equilibrium orientations can exist arbitrarily close to each other under certain conditions. The conditions for arbitrarily close equilibrium orientations are analyzed, and verified to be physically achievable with numeric examples. The findings are presented as a consideration for acceptable operating loads for magnetically levitated platforms with zero-power control.

DOI： 10.23919/LDIA.2017.8097277

Language：English   Publishing type：Research paper (other academic)  

This paper describes a new type of continuum manipulator and a modeling method. The developed manipulator has an elastic center column and springs are installed outside the center column. New mechanism can avoid unexpected shape and twisting according to the handling weight. We make a new model of continuum manipulator and analyses such an unexpected motion. The property of model is proved by the compart scene with experiments. The developed manipulator can change the stiffness of spring. Moreover, new model with consideration of influence from weights and stiffness of the manipulator has been made and introduced. With the mechanism, the manipulator can bend without twisting. In addition, the model enables to design optimal manipulator for some works.

DOI： 10.1109/ICMA.2017.8016065

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.2322/astj.16.27

Language：English  

Dynamic Programming Revisited for Aircraft Flight Trajectory Optimization

Language：Japanese   Publishing type：Research paper (scientific journal)  

Quantitative Operational Flight Efficiency Analysis of Passenger Aircraft Scheduled Flight

DOI： 10.2322/astj.14.171

Language：Japanese   Publishing type：Research paper (scientific journal)  

Trajectory Optimization using Piecewise Linear Approximation Dynamic Programming
The feasibility in optimal control applications is increasing in recent years with rapid improvement of computational capability. User-friendly practical tools are highly required to meet complex design requirements in the field of aerospace engineering and dynamic programming is regarded as a powerful tool that satisfies these necessities. On the contrary, dynamic programming possesses a drawback so called ‘menace of the expanding grid’ or dimensional difference problem in applications where the number of control variables is fewer than that of state variables. This paper proposes a unique method to approach this issue and reviews its validity and feasibility by discussing a classical problem of Linear Quadratic Regulator (LQR) and an optimal gliding flight of an airplane that the analytically given exact solutions are checked for clarity.

DOI： 10.2322/astj.14.33

Language：English   Publishing type：Research paper (scientific journal)  

Flight Trajectory Optimization for Operational Performance Analysis of Jet Passenger Aircraft

DOI： 10.2322/tastj.12.a17

Language：Japanese   Publishing type：Research paper (scientific journal)  

Evaluation Analysis on Airliner Operational Performance with Flight Trajectory Optimization using BADA Aircraft Performance Model
Fuel efficient flight is demanded due to air traffic increase, environmental concerns and skyrocketing fuel prices. To achieve an effective futuristic air traffic management system, realization of TBO (Trajectory Based Operations) optimized from departure to arrival is aimed in CARATS (Collaborative Actions for Renovation of Air Traffic Systems). In this paper, 4-D trajectory of passenger aircraft is optimized for fuel minimization on the assumption that aircraft is not bounded by any air traffic control constraints. BADA (Base of Aircraft Data) model is adopted for aircraft performance model, and dynamic programming is used to calculate the optimal trajectory. The optimal trajectory is compared with airliner's flight trajectory by evaluating fuel consumption, flight time and flight range. Examples show that considerable amounts of reduction in fuel consumption could be achieved by trajectory optimization compared to the estimated values of actual flights.

DOI： 10.2322/astj.13.1

Language：Japanese   Publishing type：Research paper (scientific journal)  

Effect of Jet Passenger Aircraft Performance Model on the Optimal Periodic Cruise Maneuver
Ideal goal of the future air traffic system is recognized that every aircraft can freely fly in the sky to optimize its own performance. Since the trajectory optimization depends on aircraft performance characteristics, the performance model is one of the key elements for practical applications. As for cruise phase, it is known that a periodic dynamic maneuver is the optimum when a simple model is used, but the maneuver is not actually used in real flight operations. This paper studies what parts of the model characteristics are influential on the optimality of the periodic dynamic maneuver in cruise flight. It reveals that engine performance model and atmospheric characteristics are two influential parameters, which justify the optimality of steady horizontal flight for cruise phase.

DOI： 10.2322/astj.12.99

Language：English   Publishing type：Research paper (scientific journal)  

Analysis of Fuel-Efficient Airliner Flight via Dynamic Programming Trajectory Optimization
Fuel-efficient flight is in strong demand due to environmental concerns and skyrocketing fuel prices. This paper analyzes airliner flight trajectory from the perspective of fuel efficiency through comparison with the optimal trajectory. Since the optimal trajectory gives the maximum achievable performance without any constraint of air traffic control, it introduces reference data for quantitative merit of the ideal flight. Dynamic programming is adopted to calculate the optimal trajectory. Examples show that considerable reduction in the fuel consumption from the estimated values for actual flights could be achieved by the trajectory optimization, where wind conditions are taken into account as well.

DOI： 10.2322/tastj.11.93

Language：English   Publishing type：Research paper (scientific journal)  

Accuracy Evaluation of an Aircraft Performance Model with Airliner Flight Data
This paper quantitatively evaluates the accuracy of the base of aircraft data (BADA) model by comparing calculated fuel flow and total fuel consumption with flight data recorded by airliners quick access recorder systems. For future more efficient air transportation system research, it is necessary to derive fuel consumption for an arbitrary flight trajectory with good accuracy. BADA, the European Organization for the Safety of Air Navigation (EUROCONTROL) aircraft performance model is widely used for such purposes, but there is only a small number of papers which discuss its accuracy with actual flight data. The purpose of this paper is to investigate whether the BADA model has sufficient accuracy to deal with the study of air transportation systems. As a result of comparison conducted for a single fleet of twin engine wide-body jet passenger aircraft, calculated fuel flow showed good agreement with the flight data in the cruise phase and it was found that the error between the BADA model and flight data falls within plus or minus 5 [%] for a whole flight.

DOI： 10.2322/tastj.11.79

Language：Japanese   Publishing type：Research paper (scientific journal)  

Passenger Aircraft Optimal Trajectory with an Arrival Time Constraint
In the future air transportation system, airspace will be efficiently used and each aircraft can optimize its own performance. Due to limited capacity of the airspace like terminal area, however, some sort of adjustment for each aircraft is necessary to maintain separation among multiple aircraft. Fixed arrival time is a basic solution to the problem. This paper studies the effect of arrival time assignment on the performance by assuming that each aircraft generates its own flight plan by minimizing its fuel consumption. Dynamic programming trajectory optimization is used to calculate the optimal flight profile composed of altitude and velocity. The result shows that the arrival time adjustment is efficiently performed in the descent phase, if the required amount of time to be adjusted is not large.

DOI： 10.2322/astj.12.31

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.2322/astj.11.131

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc.