State-space Design Methods Research Articles

Joint Situational Assessment‐Hierarchical Decision‐Making Framework for Maneuver Intent Decisions

Decision‐making in unmanned combat aerial vehicles (UCAVs) presents a multifaceted challenge because of the complexity and dynamics of the flight environment, which leads to hurdles in training convergence, low decision validity, and the dimensionality catastrophe for decision‐making neural networks. A novel framework is proposed to address breaking down the complicated decision issues, which combines the strengths of graph convolutional networks in relation extraction with the ability of hierarchical reinforcement learning. To solve the problem of decision validity under high‐dimensional inputs, the joint framework is applied to the Maneuver Intent's decision, and a maneuver library‐based state space design method is suggested. The joint framework executes adaptable strategies and flight maneuvers to address the issue of training non‐convergence or task failure due to difficult‐to‐obtain reward signals across various scenarios. Then, the recurrent curriculum training and cross‐entropy rewards are designed to train decisions on different sub‐strategies. The experimental evaluation demonstrated more flexibility and adaptability in decision‐making problems under complex tasks compared to rule‐based and reinforcement learning baseline methods. The method proposed in this article provides a novel approach to resolving intricate decision problems, and which has certain theoretical significance and reference value for engineering applications.

Compound Controller for DC Motor Servo System Based on Inner-Loop Extended State Observer

Abstract As DC motor servo systems are more and more widely applied in the manufacturing industry and aerospace domain, the requirements on control performance are increased by the complicated various working environments. With regard to the uncertainties including modeling error, parameter variations and external disturbances in DC motor servo system, one Nonlinear Extended Disturbance Observer (NESO) is constructed, and its output will be used as the design reference of disturbance compensation term in control system. Based on the as-built NESO in inner loop, one outer-loop compound controller by means of state-space design method is proposed in order to realize the high-precision position tracking ability of the servo system. Computer simulation results show that compared with conventional control schemes, the proposed control scheme can guarantee fewer tracking errors of DC motor servo system. Moreover, it possesses stronger robustness against system uncertainties including modeling error, parameter variations and friction moment disturbance.

A Design Method for Delayed Inverse Systems Using 2-delay Control

In this paper, we examine a new design method for delayed inverse systems using 2-delay digital control. The delayed inverse system for the sampled data system has a tendency to be unstable for limiting zero. Mita and Chida showed that stable delayed inverse system is designed by using 2-delay control, but this method is technical and its structure is a little complex. We propose a simple state space design method for stable delayed inverse system using 2-delay digital control. This design method has many advantages such as a simple structure and easy manipulation.

A Design Method of Stable Delayed Inverse Systems for the Strictly Proper Digital Systems (Proposition of Diagonalization Method)

This paper considers a design method for delayed-inverse systems for time-invariant strictly proper digital systems, which exactly reproduce the input with some delay. The inverse system must be stable in practical applications. It is well known that the inverse system is unstable if the system has invariant zeros outside the unit circle. The purpose of this paper is to give a state space design method for stable delayed-inverse systems such that the series-connected system, which includes the system and the stable delayed-inverse system, is a diagonal rational function. As a preliminary, we construct the delayed-inverse system by the usual method and factorize the delayed-inverse systems into several subsystems. The stable delayed-inverse system is obtained using observer design for subsystems of the delayed-inverse system. A simple numerical example is also shown.

A Design Method of Delayed Inverse Systems for the Strictly Proper Digital Systems

In this paper, we propose a state space design method of delayed inverse systems. First, a state space design method of delayed inverse systems for minimum phase systems is presented. For the non-minimum phase systems, the delayed inverse systems are unstable. Second, the stable delayed inverse system is defined so as to design the delayed inverse systems for the non-minimum phase systems such that the delayed inverse system is stable. Finally, a state space design method of the stable delayed inverse systems is proposed.

New State Space Design Method of Stable Filtered Inverse Systems and Their Application

This paper considers a design method of filtered inverse systems for time-invariant systems, which reproduce the input signal to the system approximately. The inverse system must be stable in practical applications. It is well known that the inverse system is unstable if the system has invariant zeros in the closed right half plane. Yamada and Watanabe presented a state space design method of stable filtered inverse systems for strictly proper systems with some right half plane invariant zeros. However, the series connected system with the system and filtered inverse system is not always diagonal rational function. The purpose of this paper is to give a state space design method of stable filtered inverse systems such that the series connected system with the system and stable filtered inverse system is a diagonal rational function. We construct preliminary the filtered inverse system by usual method and factorize the filtered inverse systems to several subsystems. The stable filtered inverse system is obtained using observer design for subsystems of the filtered inverse system. Numerical example is illustrated to demonstrait the effectiveness of the proposed method. Finally, an application of the stable filtered inverse systems is presented.

Design and Simulation of an Entry Edge Guide Control System for Tandem Cold Mills

A new entry edge guide control system for cold mills was designed using a dual-mode control system. One control loop regulated the cylinder pressure to prevent machine damage due to pressure surge while the other loop provided edge guide position control. The target control level was ±1.59 mm accuracy for a maximum operating strip speed of 530 mpm with coil sidewall location variations of ±12.5 mm/sec. A mathematical model was developed to simulate the dynamic behavior of the control system using the state space design method. The control system features two PID controllers, two hydraulic proportional valves, and a digital edge sensor. The PID tuning constants and the hydraulic proportional valves were specified by simulation results considering system response and signal noise. Data from 35 coils was used to investigate control performance. The results show that the average standard error is entirely acceptable. The majority of the coils are expected to have tracking errors less than the required accuracy.

A State Space Design Method of Stable Filtered Inverse Systems and Its Application to H2 Suboptimal Internal Model Control

The purpose of this paper is to present a new state-space design method of stable filtered inverse system for the strictly proper system with some right half plane invariant zeros without, solving the generalized Ricoati equation. We construct the preliminary filtered-inverse system by conventional method and divide the filtered inverse system into two subsystems. Then the problem is reduced to the problem for proper system. In addition we present an application of the stable filtered inverse system to H2 suboptimal Internal Model Control.

Pole placement in optimal regulator by continuous pole-shifting

This paper presents a method of pole placement in the linear quadratic regulator and its application to the flight control system design. There are three features in the proposed method. First, a weighting matrix that gives desired closed-loop pole locations is obtained by solving a set of differential equations. They are derived from the characteristic equation of the Hamilton matrix. Second, poles can be placed exactly at the desired positions and arbitrarily except the symmetry of complex conjugate poles with respect to the real axis. Third, it is a diagonal weighting matrix that is obtained by the proposed method. The third feature makes output regulation with desired pole locations possible. After demonstrating the effectiveness of the method through a simple literature example, it is then applied to the F-4 aircraft's lateral dynamic model. HE optimal regulator, or linear quadratic regulator (LQR), is a typical state-space design method. It has several features. For example, by imposing penalty on state variables and control inputs in a quadratic performance index, one can investigate tradeoff between system performance and control efforts. Besides, it is well known that the LQR has infinite gain margin and 60-deg phase margin for single-input systems. However, by this technique one cannot assign closed-loop pole locations. Since pole locations have a large effect on time-response characteristics, such as overshoot, rise time, etc., it is desirable to assign pole positions in the LQR design. Pole placement in the LQR is a problem associated with the selection of appropriate weighting matrices, when a set of desired closed-loop eigenvalues (CLEs) are known. This problem has been studied by many researchers since early 1970s, and many papers113 have been published in this research area. Among them, the study of Hayase 1 provides a relation between the weighting matrix and the feedback gains for a single-input system in controllable canonical form. Recently, Ohta et al. 2 showed a simple derivation of the relation. Meanwhile, for multi-input systems, Saif3 established a simple method using aggregation to compute a weighting matrix by which arbitrary and exact pole placement can be attained in a general form. He integrated the previously proposed three approaches.46 All of the aforementioned methods for multi-input systems follow Solheim's approach for placing imaginary parts as well as for placing real parts using the mirror image property.7 Another approach, which is completely different from the preceding approaches, is that of Graupe. In his method, first, differential equations of a weighting matrix with respect to the CLEs are derived, and then a weighting matrix is found as a solution of an optimization problem, wherein the difference between CLEs and assigned eigenvalues is made as small as possible.8 However, it is complicated and does not seem practical. Besides the preceding approaches, there are many approaches such as assigning eigenvalues with prescribed degree of stability, 9 placing eigenvalues into a specified region,10'11 and achieving pole placement asymptotically.12'13 In this paper, we propose a method of pole placement that is very different from the previously proposed methods. Whereas Graupe's differential equations are derived from the Riccati equation, we