Use of Rotor State Feedback to Improve Closed-Loop Stability and Handling Qualities

2012 ◽  
Vol 57 (2) ◽  
pp. 1-10 ◽  
Author(s):  
Joseph F. Horn ◽  
Wei Guo ◽  
Gurbuz Taha Ozdemir
Keyword(s):  
Disturbance Rejection ◽  
State Feedback ◽  
Closed Loop ◽  
Linear Quadratic Regulator ◽  
Linear Analysis ◽  
Dynamic Inversion ◽  
Control Law ◽  
Linear Quadratic ◽  
Handling Qualities ◽  
Model Following

A rotorcraft control law that uses rotor state feedback (RSF) is presented and demonstrated in simulation. The baseline control law uses a model following/dynamic inversion approach to control the roll, pitch, and yaw axes. The RSF control law was designed to integrate seamlessly with the baseline control law and can be readily engaged or disengaged. The RSF control gains were designed using linear quadratic regulator synthesis. Linear analyses showed that RSF could allow for the feedback gains on rates and attitude to be increased to values that would result in closed-loop instability without the use of RSF. The increased gains can be used to increase bandwidth and improve disturbance rejection. The controller was tested on a nonlinear model in both non–real-time and piloted simulations, and results confirmed the linear analysis. The RSF control law design has potential to improve handling qualities by allowing higher bandwidth and better disturbance rejection with reduced risk of closed-loop instability.

scholarly journals Application of LQR Full-State Feedback Controller for Rotational Inverted Pendulum

2021 ◽  
Vol 2111 (1) ◽  
pp. 012006
Author(s):  
N Setiawan ◽  
G N P Pratama
Keyword(s):  
State Feedback ◽  
Inverted Pendulum ◽  
Equilibrium Points ◽  
Linear Quadratic Regulator ◽  
Feedback Controller ◽  
Control Law ◽  
Linear Quadratic ◽  
State Feedback Controller ◽  
Full State ◽  
Full State Feedback

Abstract The rotational inverted pendulum is an interesting subject for some researchers, especially control engineers. Its nonlinear and underactuated characteristic make it quite challenging to stabilize it. Hence, a proper control law is a must to make it stable. Here, in this paper, we present a control law using LQR (Linear-Quadratic Regulator) to stabilize the rotational inverted pendulum. The experiments are carried out by linearizing the model and simulate the response in MATLAB. The results show that the controller succeeds to stabilize the states of rotational inverted pendulum to their respective equilibrium points. Even more, it provides zero settling errors.

A New Turbo-shaft Engine Control Law during Variable Rotor Speed Transient Process

2015 ◽  
Vol 32 (4) ◽  
Author(s):  
Wei Hua ◽  
Lizhen Miao ◽  
Haibo Zhang ◽  
Jinquan Huang
Keyword(s):  
Transient Process ◽  
Closed Loop ◽  
Dynamic Change ◽  
Linear Quadratic Regulator ◽  
Integrated System ◽  
Control Law ◽  
Rotor Speed ◽  
Linear Quadratic ◽  
Loop Control ◽  
Fuel Flow

AbstractA closed-loop control law employing compressor guided vanes is firstly investigated to solve unacceptable fuel flow dynamic change in single fuel control for turbo-shaft engine here, especially for rotorcraft in variable rotor speed process. Based on an Augmented Linear Quadratic Regulator (ALQR) algorithm, a dual-input, single-output robust control scheme is proposed for a turbo-shaft engine, involving not only the closed loop adjustment of fuel flow but also that of compressor guided vanes. Furthermore, compared to single fuel control, some digital simulation cases using this new scheme about variable rotor speed have been implemented on the basis of an integrated system of helicopter and engine model. The results depict that the command tracking performance to the free turbine rotor speed can be asymptotically realized. Moreover, the fuel flow transient process has been significantly improved, and the fuel consumption has been dramatically cut down by more than 2% while keeping the helicopter level fight unchanged.

scholarly journals Trajectory Tracking Control for Small-Scale Unmanned Helicopters with Mismatched Disturbances Based on a Continuous Sliding Mode Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xing Fang ◽  
Yujia Shang
Keyword(s):  
Sliding Mode Control ◽  
Disturbance Rejection ◽  
Tracking Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Small Scale ◽  
Control Law ◽  
Trajectory Tracking Control ◽  
Mode Control ◽  
Mismatched Disturbances

A novel continuous sliding mode control (CSMC) strategy based on the finite-time disturbance observer (FTDO) is proposed for the small-scale unmanned helicopters in the presence of both matched and mismatched disturbances. First, a novel sliding surface is designed based on the estimates of the mismatched disturbances and their derivatives obtained by the FTDO. Then, a continuous sliding mode control law is developed, which does not lead to any chattering phenomenon. Furthermore, the closed-loop helicopter system is proved to be asymptotically stable. Finally, the excellent hovering and tracking performance, as well as the powerful disturbance rejection capability of the proposed novel CSMC method, is validated by the simulation results.

A Stochastic Regulator for Integrated Communication and Control Systems: Part II—Numerical Analysis and Simulation

1991 ◽  
Vol 113 (4) ◽  
pp. 612-619 ◽  
Author(s):  
Luen-Woei Liou ◽  
Asok Ray
Keyword(s):  
Control Systems ◽  
Numerical Procedure ◽  
Linear Quadratic Regulator ◽  
State Feedback Control ◽  
Control Law ◽  
Linear Quadratic ◽  
Simulation Experiments ◽  
Integrated Communication ◽  
And Control ◽  
Future Work

A state feedback control law has been derived in Part I [1] of this two-part paper on the basis of an augmented plant model [2, 3, 4] that accounts for the randomly varying delays induced by the network in Integrated Communication and Control Systems (ICCS). The control algorithm was formulated as a linear quadratic regulator problem and then solved using the principle of dynamic programming and optimality. This paper, which is the second of two parts, presents (i) a numerical procedure for synthesizing the control parameters and (ii) results of simulation experiments for verification of the above control law using the flight dynamic model of an advanced aircraft. This two-part paper is concluded with recommendations for future work.

Optimal attitude trajectory planning method for CMG actuated spacecraft

2017 ◽  
Vol 232 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Lijun Zhang ◽  
Chunmei Yu ◽  
Shifeng Zhang ◽  
Hong Cai
Keyword(s):  
Trajectory Planning ◽  
Closed Loop ◽  
Pseudospectral Method ◽  
Linear Quadratic Regulator ◽  
Fixed Time ◽  
Open Loop ◽  
Planning Method ◽  
Global Perspective ◽  
Linear Quadratic ◽  
Loop Control

This paper presents an optimal attitude trajectory planning method for the spacecraft equipped with control moment gyros as the actuators. Both the fixed-time energy-optimal and synthesis performance optimal cases are taken into account. The corresponding nonsingular attitude maneuvering trajectories (i.e. open-loop control trajectories) with the consideration of a series of constraints are generated via Radau pseudospectral method. Compared with the traditional steering laws, the optimal steering law designed by this method can explicitly avoid the singularity from the global perspective. A linear quadratic regulator closed-loop controller is designed to guarantee the trajectory tracking performance in the presence of initial errors, inertia uncertainties and external disturbances. Simulation results verify the validity and feasibility of the proposed open-loop and closed-loop control methods.

Robust launch vehicle’s generalized dynamic inversion attitude control

2017 ◽  
Vol 89 (6) ◽  
pp. 902-910 ◽  
Author(s):  
Uzair Ansari ◽  
Abdulrahman H. Bajodah
Keyword(s):  
Attitude Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Dynamic Scaling ◽  
Dynamic Inversion ◽  
Control Law ◽  
Successful Implementation ◽  
Robust Tracking Control ◽  
Content Type ◽  
Dynamic Constraints

Purpose To design a robust attitude control system for the ascent flight phase of satellite launch vehicles (SLVs). Design/methodology/approach The autopilot is based on generalized dynamic inversion (GDI). Dynamic constraints are prescribed in the form of differential equations that encapsulate the control objectives, and are generalized inverted using the Moore-Penrose Generalized Inverse (MPGI) based Greville formula to obtain the control law. The MPGI is modified via a dynamic scaling factor for assuring generalized inversion singularity-robust tracking control. An additional sliding mode control (SMC) loop is augmented to robustify the GDI closed-loop system against model uncertainties and external disturbances. Findings The robust GDI control law allows for two cooperating controllers that act on two orthogonally complement control spaces: one is the particular controller that realizes the dynamic constraints, and the other is the auxiliary controller that is affined in the null control vector, and is used to enforce global closed-loop stability. Practical implications Orthogonality of the particular and the auxiliary control subspaces ensures noninterference of the two control actions, and thus, it ensures that both actions work toward a unified goal. The robust control loop increases practicality of the GDI control design. Originality/value The first successful implementation of GDI to the SLV control problem.

scholarly journals H∞Control for Network-Based 2D Systems with Missing Measurements

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Bu Xuhui ◽  
Wang Hongqi ◽  
Zheng Zheng ◽  
Qian Wei
Keyword(s):  
State Feedback ◽  
Closed Loop ◽  
Disturbance Attenuation ◽  
Linear Matrix ◽  
Control Law ◽  
2D Systems ◽  
Matrix Inequalities ◽  
Stochastic Variable ◽  
Missing Measurements ◽  
Binary Distribution

The problem ofH∞control for network-based 2D systems with missing measurements is considered. A stochastic variable satisfying the Bernoulli random binary distribution is utilized to characterize the missing measurements. Our attention is focused on the design of a state feedback controller such that the closed-loop 2D stochastic system is mean-square asymptotic stability and has an  H∞disturbance attenuation performance. A sufficient condition is established by means of linear matrix inequalities (LMIs) technique, and formulas can be given for the control law design. The result is also extended to more general cases where the system matrices contain uncertain parameters. Numerical examples are also given to illustrate the effectiveness of proposed approach.

Supersonic transport aircraft longitudinal flight control law design

2004 ◽  
Vol 108 (1084) ◽  
pp. 319-329
Author(s):  
A. J. Steer
Keyword(s):  
Flight Control ◽  
Dynamic Inversion ◽  
Control Law ◽  
Transport Aircraft ◽  
Handling Qualities ◽  
Supersonic Transport ◽  
Linear Dynamic ◽  
Non Linear ◽  
Quality Design ◽  
Handling Quality

Abstract Modern civil transport aircraft utilise increasingly complex command and stability augmentation systems to restore stability, optimise aerodynamic performance and provide the pilot with the optimum handling qualities. Provided it has sufficient control power a second generation fly-by-wire supersonic transport aircraft should be capable of exhibiting similarly desirable low-speed handling qualities. However, successful flight control law design requires identification of the ideal command response type for a particular phase of flight, a set of valid handling quality design criteria and piloted simulation evaluation tasks and metrics. A non-linear mathematical model of the European supersonic transport aircraft has been synthesized on the final approach to land. Specific handling quality design criteria have been proposed to enable the non-linear dynamic inversion flight control laws to be designed, with piloted simulation used for validation. A pitch rate command system, with dynamics matched to the aircraft’s flight path response, will consistently provide Level 1 handling qualities. Nevertheless, pre-filtering the pilot’s input to provide a second order pitch rate response, using the author’s suggested revised constraints on the control anticipation parameter will generate the best handling qualities during the terminal phase of flight. The resulting pre-filter can be easily applied to non-linear dynamic inversion inner loop controllers and has simple and flight proven sensor requirements.

scholarly journals Continuous-Time Perfect Control Algorithm—A State Feedback Approach

2021 ◽  
Vol 11 (16) ◽  
pp. 7466
Author(s):  
Marek Krok ◽  
Wojciech P. Hunek ◽  
Paweł Majewski
Keyword(s):  
Design Process ◽  
Process Simulation ◽  
Continuous Time ◽  
Control Algorithm ◽  
State Feedback ◽  
Closed Loop ◽  
Control Design ◽  
Control Law ◽  
New Approach

In this paper, a new approach to the continuous-time perfect control algorithm is given. Focusing on the output derivative, it is shown that the discussed control law can effectively be implemented in terms of state-feedback scenarios. Moreover, the application of nonunique matrix inverses is also taken into consideration during the perfect control design process. Simulation examples given within this work allow us to showcase the main properties obtained for continuous-time perfect control closed-loop plants.

scholarly journals Boundary stabilization and disturbance rejection for an unstable time fractional diffusion-wave equation

2022 ◽  
Author(s):  
Hua-Cheng Zhou ◽  
Ze-Hao Wu ◽  
Bao-Zhu Guo ◽  
Yangquan Chen
Keyword(s):  
Output Feedback ◽  
Disturbance Rejection ◽  
State Feedback ◽  
Closed Loop ◽  
External Disturbance ◽  
Fractional Diffusion ◽  
Loop System ◽  
Boundary Stabilization ◽  
Closed Loop System ◽  
Diffusion Wave

In this paper, we study boundary stabilization and disturbance rejection problem for an unstable time fractional diffusion-wave equation with Caputo time fractional derivative. For the case of no boundary external disturbance, both state feedback control and output feedback control via Neumann boundary actuation are proposed by the classical backstepping method. It is proved that the state feedback makes the closed-loop system Mittag-Leffler stable and the output feedback makes the closed-loop system asymptotically stable. When there is boundary external disturbance, we propose a disturbance estimator constructed by two infinite dimensional auxiliary systems to recover the external disturbance. A novel control law is then designed to compensate for the external disturbance in real time, and rigorous mathematical proofs are presented to show that the resulting closed-loop system is Mittag-Leffler stable and the states of all subsystems involved are uniformly bounded. As a result, we completely resolve, from a theoretical perspective, two long-standing unsolved mathematical control problems raised in [Nonlinear Dynam., 38(2004), 339-354] where all results were verified by simulations only.

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