Atsushi Satoh

Simultaneous Realization of Handling and Gust Responses: In-Flight Simulator Controller Design

This paper addresses the design problem of a flight controller for an in-flight simulator, in which the controller is required to realize the gust response and the handling response of the target aircraft simultaneously. A two-degree-of-freedom model-matching controller is proposed to meet this requirement, with feedback and feedforward controllers designed to vary the gust response and handling response characteristics, respectively. The controller is designed in two steps: the feedback controller is first designed via the H ∞ model-matching approach, then the feedforward controller is designed as a filtered right inverse system of the closed-loop system comprising the plant dynamics and the feedback controller. Controllers are designed to enable a research aircraft to simulate the lateral-directional motions of two target aircraft models: a Boeing 747 and a Convair 880M. Hardware-in-the-loop simulations and flight tests with the designed controllers confirm that they achieve the simultaneous realization of gust response and handling response of the target aircraft. Additionally, an in-flight simulator controller for investigating handling qualities for lateral-directional motions is designed, and hardware-in-the-loop simulations and flight tests confirm its applicability to handling-quality investigation.

Quadratic Stabilization With Partial Eigenstructure Assignment: Application To Flight Control Design

Abstract This paper proposes a new design method for state feedback laws which simultaneously achieve quadratic stabilization and assignment of eigenstructure corresponding to partial closed-loop poles. As a typical application of the method, flight control design for an aircraft model with structured uncertainty is presented. In contrast to previous studies, This method assigns dominant system modes (e.g. roll mode, dutch-roll mode) with others (e.g. actuator internal modes) unspecified. This means that more freedom is left for the design of feedback law than previous methods. This freedom can be utilized for ensuring robust stability such as quadratic stability. The design problem is reduced to a practically attainable numerical optimization problem under LMI (Linear Matrix Inequality) constraints and a non-linear equality constraint.

Flight Control Experiment of Multipurpose-Aviation-Laboratory-alpha In-Flight Simulator

This paper reports the results of experimental verification of flight controllers for the multipurpose-aviation-laboratory-α (MuPAL-α) in-flight simulator. The flight controller design requirements are twofold: to suppress the effects of gusts on MuPAL-α motions and to realize a wide range of maneuverability, i.e., handling characteristics, without controller redesign. Using a previously proposed two-step design method for two-degrees-of-freedom model-matching controllers, flight controllers were designed for the linearized longitudinal and lateral-directional motions of MuPAL-α, and their performance was examined by hardware-in-the-loop simulations and flight tests with several maneuverability models. These experiments confirmed that MuPAL-α with our controllers achieves gust suppression and is capable of simulating various types of handling characteristics simply by replacing the model that defines the characteristics to be examined.

State Feedback Synthesis of Linear Reset Control with L2 Performance Bound via LMI Approach

Abstract In this paper, a simultaneous design of linear dynamical feedback controller and resetting rule to stabilize the linear continuous-time plant is considered. Strictly decreasing type Lyapunov-like function, which is recently proposed by Nesic et al., is considered to obtain the tractable conditions via LMI approach. As the main result, it is shown that a sufficient existence condition of the L 2 stabilizing reset control with general jump matrix is reduced to an LMI problem with a line search parameter.

Loose eigenstructure assignment via rank-one LMI approach with application to transient response shaping in H ∞ control

This article proposes a new regional eigenstructure assignment via rank-one LMI approach. A gain parameter condition for the regional eigenvalue/eigenstructure assignment is newly derived. This assignment condition is easily combined with H ∞ design by means of enhanced LMI characterisation. In the present approach, the desired assignment of closed-loop eigenvalues (i.e. poles) are not previously fixed but constrained into individual assignment regions to bring us more design freedom than classical exact assignment. The regional assignment discussed in this article never falls into an ordinary LMI root clustering because the union of assignment regions is disjoint in general. Each closed-loop eigenvector is also constrained into individual alignment cone. To show the practical use of the extra design freedom brought by regional assignment, a transient response shaping in H ∞ design is also discussed. A useful design algorithm based on linearisation algorithm is proposed.

Disturbance suppression via robust MPC using prior disturbance data: Low computational complexity method

This note addresses disturbance suppression problem for uncertain plant systems using prior disturbance data which contain some measurement errors, and gives a further result which attains lower computational complexity than our previously proposed method. Under the conditions that the plant uncertainties are assumed to be expressed by bounded but time-invariant uncertain delays at the control input and the measurement errors are expressed as affine with respect to some bounded constant uncertain vector, we have already proposed a MPC-based controller which achieves disturbance suppression with robustness against the plant uncertainties and the measurement errors. In this paper, we tackle the same problem but under the condition that the implemented computing power is limited. For this problem, we propose a simple methodology, i.e. constant inputs are supposed for several steps. We apply our proposed method to flight controller design problem to suppress vertical acceleration driven by turbulence, i.e. Gust Alleviation (GA) flight controller design problem, and demonstrate the applicability with numerical simulations.

Disturbance suppression via robust MPC using prior disturbance data application to flight controller design for Gust Alleviation

This paper addresses disturbance suppression problem for uncertain plant systems using prior disturbance data which contain some measurement errors. We tackle optimal control input design problem using Model Predictive Control (MPC) scheme in which a priori measured disturbance data are exploited. We show that if the uncertainties of the plant systems are expressed by bounded but time-invariant uncertain delays at the control input, then we only have to consider finitely many plant models instead of the original uncertain plant systems. Furthermore, we also show that if the measurement errors in prior disturbance data are expressed as affine with respect to some constant uncertain vector, whose elements are bounded, then we only have to evaluate the measurement errors at the vertices of the vector. Using these, we propose a robust MPC design with finitely many conditions for our addressed problem. Finally, we apply our proposed method to flight controller design problem for suppressing the vertical acceleration driven by turbulence, i.e. Gust Alleviation (GA) flight controller design problem.

Transient response shaping in H/sub /spl infin// control by eigenstructure assignment to convex regions

In this paper, eigenstructure assignment to a set of convex regions is proposed. Transient response shaping of H/sub /spl infin// control via the proposed approach is also discussed. Firstly, closed-loop eigenvalue (pole) assignment to a set of convex Lyapunov regions is proved via rank-one LMI (linear matrix inequality) approach. Secondly, as the first result of this paper, eigenstructure assignment to convex regions is proved. Closed-loop eigenvector misalignment angle bound condition is reduced to a rank-one LMI condition and easily combined with the eigenvalue assignment problem. Finally, as the second result of this paper, transient response shaping in H/sub /spl infin// control by the presented approach is proposed. By using the presented loose assignment approach, design trade-off between the closed-loop eigenstructure assignment and H/sub /spl infin// condition can be easily considered. These two conditions are connected via enhanced LMI characterization.

Partial pole placement with specified stability margins

Proposes a design method for a state feedback control law which simultaneously ensures specified stability margins and partial pole placement. This design problem is reduced to a feasibility problem with LMI constraints and a non-linear equality constraint.

Partial Pole Placement by Discrete-Time LQ Control and its Sampled-Data Performance

Abstract This paper gives a design method for discrete-time optimal control, and then studies its performance from a sampled-data point of view. First, as discrete-time control, a state feedback gain is designed which places part of the closed-loop poles exactly at specified points inside the unit circle, and is linear quadratic (LQ) optimal for some weightings at the same time. This is achieved by placing the rest of the poles sufficiently close to the origin, thereby satisfying a modified circle criterion, a solution to the inverse problem of discrete-time LQ control. Secondly, it is checked whether thus obtained (pure) discrete-time feedback is again optimal as a sampled-data control system; i.e., whether it minimizes some continuous-time performance index.