Kazuya Masui

Restructurable Guidance and Control for Aircraft with Failures Considering Gust Effects

This paper presents a procedure for designing a fault-tolerant guidance and control system for a damaged aircraft using the simultaneous online fault/wind estimation and the nonlinear restructurable guidance and control law. The algorithm employs an extended Kalman filter (EKF) and a nonlinear inverse dynamics (NID) controller with the singular perturbation method. The EKF, which is based on the six-degree-of-freedom nonlinear aircraft equations of motion, simultaneously estimates the aerodynamic derivative changes and the wind-velocity components. The NID controller computes the required control-surface deflections and engine thrust not only to stabilize damaged aircraft but also to enable the aircraft to track the reference trajectory using the estimated results in a gusty environment. The estimation algorithm is evaluated through flight-test data obtained by using the experimental aircraft. Numerical simulations are carried out to verify the guidance and control capability of damaged aircraft under gusty conditions.

Online Four-Dimensional Flight Trajectory Search and its Flight Testing

Online flight trajectory optimization algorithms are developed in order to guide and control aircraft for emergency landing. Further, the applicability of generated flight trajectories to real flights is evaluated using a flight simulator and an experimental aircraft. By combining the real-time A* path search algorithm with the R-TABU optimization method and an inverse dynamic method, a near-optimal four-dimensional flight trajectory is computed in real time. The proposed method is applied to design a flight trajectory for emergency landing. The generated flight trajectory is shown to pilots as a tunnel-in-the-sky image in order to track the trajectory by manual operation. Both the simulation and flight experiments refine the algorithms and demonstrate the applicability of the proposed system.

Real-Time Flight Trajectory Optimization and Its Verification in Flight

T HIS Note presents a real-time flight trajectory optimization method. The flight trajectory that minimizes the fuel consumption or flight time of an aircraft can be solved with optimization. Because the optimization is time-consuming, the optimal flight trajectory needs to be obtained before flight. This, however, cannot cope with unexpected situations in flight. Thus, the real-time optimization, which optimizes the flight trajectory with the transition of the flight state, is important. The final goal of our study is to establish the real-time trajectory generation applicable to emergency landing approaches. Though the present flight management system provides the optimal flight path for a flight plan in normal operations, it cannot operate in emergency situations. This Note presents a fundamental real-time trajectory optimization algorithm and its flight validation. Many studies about real-time flight-path generation have produced a flight path by connecting the trim conditions in prestored databases [1,2]. In these studies, computer-assisted simulations were performed, but there were few actual flight experiments. Additionally, it is difficult to generate nonstational trajectories and the wind effects were not considered. In Japan, the Society of Japanese Aerospace Companies has promoted research on the development of a fault-tolerant flight control system. In a proceeding study, Suzuki et al. proposed a flight trajectory search method composed of a realtime A* algorithm and a random tabu search method [3]. They also conducted flight experiments. This random-based method, however, lacks convergent stability, so it often does not produce the appropriate trajectory. We have taken over this study, and in this Note we apply a direct collocation method including some schemes to solve the preceding problems. Actual flight experiments are also conducted to prove the effectiveness of the method. The experimental aircraft is MuPAL, the Multi-Purpose Aviation Laboratory, developed by JAXA (Japan Aerospace Exploration Agency) [4]. It has a high-precision Global Positioning System/inertial navigation system and a three-axis airspeed sensor. The system allows the estimation of the wind velocity and direction during flight. MuPALalso has a tunnel-in-the-sky display, which was developed by JAXA [5]. The experiments were conducted under manual tracking control using the display. In the future, the trajectory generated by the real-time optimization method will be tracked by an automaticflight control systembeing developed in the research on the fault-tolerant flight control system.

Simple Adaptive Control with PID for MIMO Fault Tolerant Flight Control Design

This paper describes a fault-tolerant flight control method using Simple Adaptive Control augmented with a PID controller (PID-SAC). The aim of this paper is to demonstrate control of an aircraft using PID-SAC control even if the dynamic characteristics change due to damage to the aircraft. We show actual flight test results in the case where the aileron or rudder authority suddenly diminishes mid-flight. Through actual flight tests, we demonstrate the superiority of this new control method in comparison to a conventional control method. One of the biggest advantages of PID-SAC approach is that a PID-SAC controller has high flexibility and extensibility to another control scheme.

Flight test of fault-tolerant flight control system using simple adaptive control with PID controller

Purpose This paper aims to demonstrate the effectiveness of a fault-tolerant flight control method by using simple adaptive control (SAC) with PID controller. Design/methodology/approach Numerical simulations and flight tests are executed for pitch angle and roll angle control of research aircraft MuPAL-α under the following fault cases: sudden reduction in aileron effectiveness, sudden reduction in elevator effectiveness and loss of longitudinal static stability. Findings The simulations and flight tests reveal the effectiveness of the proposed SAC with PID controller as a fault-tolerant flight controller. Practical implications This research includes implications for the development of vehicles’ robustness. Originality/value This study proposes novel SAC-based flight controller and actually demonstrates the effectiveness by flight test.

Flight Test Evaluation of Non-Linear Dynamic Inversion Controller

** †† A guidance and control system for emergency landings is developed and flight tests are carried out using an experimental aircraft. The system consists of an online optimal trajectory design method and a tracking control method. The online version of a direct collocation method is developed and a nonlinear dynamic inversion with a singular perturbation method is designed for tracking optimized 4D trajectories. Numerical simulations and hardware-in-the-loop simulations are carried out before real flight tests. The flight control system is successfully evaluated in real flight experiments using modified Dornier 228 with fly-by-wire control systems.