scholarly journals Hybrid Trajectory Optimization Method and Tracking Guidance for Variable-Sweep Missiles

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhifang Wei ◽  
Yang Cheng ◽  
Xiangxiang Guo ◽  
Senlin Liu
Keyword(s):  
Trajectory Optimization ◽  
Pseudospectral Method ◽  
Linear Quadratic Regulator ◽  
Attack Angle ◽  
Hybrid Optimization ◽  
Optimization Approach ◽  
Optimization Strategy ◽  
Linear Quadratic ◽  
Sweep Angle ◽  
The Impact

In this paper, an offline hybrid trajectory optimization approach is proposed for variable-sweep missiles to explore the superiority in the diving phase. Aiming at the maximal terminal velocity with the impact angle constraint, the trajectory optimization model is formulated under multiple constraints, and the aerodynamic analysis in different sweep angles is discussed. Unlike only the attack angle used for the optimization process traditionally, the two-variable optimization scheme on both the attack angle and sweep angle is investigated for variable-sweep missiles. Then, the trajectory optimization problem is transformed into the nonlinear programming problem via a hybrid optimization strategy combining the Gauss pseudospectral method and direct shooting method to obtain the high precision and fast convergence solution. Finally, to verify the feasibility of the optimal trajectory under uncertainties, the tracking guidance law is designed on basis of the gain scheduled linear quadratic regulator control. Numerical simulation results reveal not only of the proposed hybrid optimization strategy but also of the superiority of variable-sweep missiles compared with traditional missiles.

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.

scholarly journals Optimization of the linear quadratic regulator (LQR) control quarter car suspension system using genetic algorithm

2016 ◽  
Vol 36 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Mahesh Nagarkar ◽  
G. J. Vikhe Patil
Keyword(s):  
Genetic Algorithm ◽  
Linear Quadratic Regulator ◽  
Suspension System ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Linear Quadratic ◽  
Multi Objective ◽  
Weighting Matrix ◽  
Car Suspension ◽  
Quarter Car

<p>In this paper, a genetic algorithm (GA) based in an optimization approach is presented in order to search the optimum weighting matrix parameters of a linear quadratic regulator (LQR). A Macpherson strut quarter car suspension system is implemented for ride control application. Initially, the GA is implemented with the objective of minimizing root mean square (RMS) controller force. For single objective optimization, RMS controller force is reduced by 20.42% with slight increase in RMS sprung mass acceleration. Trade-off is observed between controller force and sprung mass acceleration. Further, an analysis is extended to multi-objective optimization with objectives such as minimization of RMS controller force and RMS sprung mass acceleration and minimization of RMS controller force, RMS sprung mass acceleration and suspension space deflection. For multi-objective optimization, Pareto-front gives flexibility in order to choose the optimum solution as per designer’s need.</p>

Energetically-Optimal Discrete and Continuous Stabilization of the Rimless Wheel With Torso

2019 ◽  
Author(s):  
Wankun Sirichotiyakul ◽  
Aykut C. Satici ◽  
Eric S. Sanchez ◽  
Pranav A. Bhounsule
Keyword(s):  
Closed Loop ◽  
Estimation Method ◽  
Linear Quadratic Regulator ◽  
Region Of Attraction ◽  
Closed Loop System ◽  
Linear Quadratic ◽  
Walking Gait ◽  
Rimless Wheel ◽  
The Impact ◽  
Discrete Controller

Abstract In this work, we discuss the modeling, control, and implementation of a rimless wheel with torso. We derive and compare two control methodologies: a discrete-time controller (DT) that updates the controls once-per-step and a continuous-time controller (CT) that updates gains continuously. For the discrete controller, we use least-squares estimation method to approximate the Poincaré map on a certain section and use discrete-linear-quadratic-regulator (DQLR) to stabilize a (closed-form) linearization of this map. For the continuous controller, we introduce moving Poincaré sections and stabilize the transverse dynamics along these moving sections. For both controllers, we estimate the region of attraction of the closed-loop system using sum-of-squares methods. Analysis of the impact map yields a refinement of the controller that stabilizes a steady-state walking gait with minimal energy loss. We present both simulation and experimental results that support the validity of the proposed approaches. We find that the CT controller has a larger region of attraction and smoother stabilization as compared with the DT controller.

scholarly journals Evaluation of Three Common Algorithms for Structure Active Control

2017 ◽  
Vol 7 (3) ◽  
pp. 1638-1646
Author(s):  
M. Sareban
Keyword(s):  
Fuzzy Control ◽  
Active Control ◽  
Control Method ◽  
Variable Mass ◽  
Structural Response ◽  
Linear Quadratic Regulator ◽  
Relative Displacement ◽  
Control Methods ◽  
Linear Quadratic ◽  
The Impact

Recently active structure controllers were considered to deal with the impact of earthquake forces and the result of the investigations provided multiple algorithms to calculate force control and many different ways to apply these forces on the structure. In this study, the efficiency and effectiveness of three methods (linear quadratic regulator, fuzzy logic and pole assigning) are investigated. In addition, three buildings with different height classes with an active tuned mass damper (ATMD) on the top floor are considered to compare the active control methods. Examples with known mass and stiffness and with variable mass are considered. The results show that all three control methods used for the ATMD device reduce the structural response. The fuzzy control method, caused a sharp decline in relative displacement of building floors up to 80%. But in LQR and pole allocation procedures the applied force is limited. The best performance of fuzzy control is for high-rise buildings. The three different methods of control are stable in different masses and even under a random change of floor masses, their effectiveness can be trusted.

scholarly journals A pseudospectral method for budget-constrained infinite horizon optimal control problems

2021 ◽  
Vol 71 ◽  
pp. 145-154
Author(s):  
Angie Burtchen ◽  
Valeriya Lykina ◽  
Sabine Pickenhain
Keyword(s):  
Optimal Control ◽  
Optimal Control Problems ◽  
Numerical Solutions ◽  
Infinite Horizon ◽  
Pseudospectral Method ◽  
Linear Quadratic Regulator ◽  
Approximate Solutions ◽  
Control Problems ◽  
Linear Quadratic ◽  
Weighted Functional Spaces

In this paper a generalization of the indirect pseudo-spectral method, presented in [17], for the numerical solution of budget-constrained infinite horizon optimal control problems is presented. Consideration of the problem statement in the framework of weighted functional spaces allows to arrive at a good approximation for the initial value of the adjoint variable, which is inevitable for obtaining good numerical solutions. The presented method is illustrated by applying it to the budget-constrained linear-quadratic regulator model. The quality of approximate solutions is demonstrated by an example.

A hybrid optimization strategy for the maintenance of the wheels of metro vehicles: Vehicle turning, wheel re-profiling, and multi-template use

2017 ◽  
Vol 232 (3) ◽  
pp. 832-841 ◽  
Author(s):  
Wei Zhu ◽  
Di Yang ◽  
Jun Huang
Keyword(s):  
Optimal Solution ◽  
Hybrid Optimization ◽  
Optimization Approach ◽  
Optimization Strategy ◽  
Wheel Wear ◽  
Rail Systems ◽  
Common Strategy ◽  
Shanghai Metro ◽  
Open Nature

The wheel–rail contact relationship has a great impact on the security and reliability of metro vehicles in service. In particular, wear modeling and maintenance optimization of the wheels play significant roles with regard to both safety and cost. However, it is difficult to provide a satisfactory model of wheel wear because of the open nature of real wheel–rail systems and the constantly varying environmental conditions in which they operate. Historically, re-profiling, which also has its limitation to some extent, was adopted as a common strategy to restore the original profiles of the worn wheels. Acknowledging that re-profiling is not the only strategy for dealing with wheel wear, the authors of this study have developed a more advanced optimization approach that includes two more strategies, namely, vehicle turning and multi-template use, to give as near an optimal solution as possible. Vehicle turning refers to the reversal of the vehicle’s orientation on the rail, whereas multi-template use refers to the situation where different re-profiling templates are used alternately. In this paper, re-profiling, vehicle turning, and multi-template use have been discussed separately. Then a hybrid optimization strategy for the maintenance of the wheels of metro vehicles has been proposed, with the aim of maximizing the wheel life while minimizing the relevant costs. An initial case study on the Shanghai Metro system shows that the proposed approach is able to provide a more reasonable solution for the optimization of the maintenance strategies.

scholarly journals ANALYSIS OF CONTROL METHODS AND ALGORITHMS FOR WALKING ROBOTS TAKING INTO ACCOUNT THE NONLINEAR PROPERTIES OF THE ROBOT SEN-SOR SYSTEM

2019 ◽  
pp. 136-144
Author(s):  
С. Савин ◽  
S. Savin ◽  
Л. Ворочаева ◽  
L. Vorochaeva
Keyword(s):  
Quadratic Programming ◽  
Robot Control ◽  
Linear Quadratic Regulator ◽  
Alternative Methods ◽  
Walking Robots ◽  
Linear Quadratic ◽  
Nonlinear Properties ◽  
Torque Values ◽  
The Impact

The work is focused on the control of two-legged walking robots. The robot control task for two-legged walking robots is formulated as a quadratic programming task, which allows consideration of unilateral mechanical constraints in the form of inequality constraints caused by the friction cones and torque limitations of the drives. However, in order to assess the quality of such control approach it is important to analyze this system relative to the alternative methods. Three types of regulators are compared: CTC (Computed Torque Controller), linear quadratic regulator with constraints CLQR restrictions (Constrained Linear Quadratic Regulator) and the controller based on the quadratic programming NQPC (Nested Quadratic Programming-based Controller). Particular attention is paid to the impact of inaccuracies of the sensor system on the quality of the robot control system. The study covers cases where a dynamic observer can be used to compensate for inaccuracies of sensors, as well as cases where restrictions are imposed on the torque values in the robot joints. The simulation results show there is a sensor parameter area in which the quality of the regulator operation is robust with respect to small changes in the nonlinear properties of sensors, and such parameter areas are characteristic for systems with and without an observer, as well as for systems with restrictions on the torque values and without them.

scholarly journals A New Efficient Adaptive Control of Torsional Vibrations Induced by Switched Nonlinear Disturbances

2019 ◽  
Vol 29 (2) ◽  
pp. 285-303 ◽  
Author(s):  
Maciej Wasilewski ◽  
Dominik Pisarski ◽  
Robert Konowrocki ◽  
Czesław I. Bajer
Keyword(s):  
Linear Quadratic Regulator ◽  
Drill String ◽  
Friction Torque ◽  
Nonlinear Behaviour ◽  
Torsional Vibrations ◽  
Linear Quadratic ◽  
Stick Slip ◽  
Direct Measurements ◽  
Excited Vibration ◽  
The Impact

Abstract Torsional vibrations induced in drilling systems are detrimental to the condition of the machine and to the effectiveness of the engineering process. The cause of vibrations is a nonlinear and unknown friction between a drill string and the environment, containing jumps in its characteristics. Nonlinear behaviour of the friction coefficient results in self-excited vibration and causes undesirable stick-slip oscillations. The aim of this paper is to present a novel adaptive technique of controlling vibrating systems. The scheme is based on the linear quadratic regulator and uses direct measurements of the friction torque to synthesize its linear dynamic approximation. This approach allows generating a control law that takes into account the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The controller’s performance is examined via numerical simulations of the stabilization of the drilling system. The proposed solution outperforms the comparative LQG regulator in terms of the minimization of the assumed cost functional and the overall stability of the control system under the nonlinear disturbance.

Load Alleviation Flight Control Design using High-Order Dynamic Models

2020 ◽  
Vol 65 (3) ◽  
pp. 1-15
Author(s):  
Umberto Saetti ◽  
Joseph F. Horn
Keyword(s):  
Flight Control ◽  
State Feedback ◽  
Dynamic Models ◽  
Linear Time ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Linear Time Invariant ◽  
Harmonic Decomposition ◽  
The Impact ◽  
Pseudo Inverse

The present study considers two notional rotorcraft models: a conventional utility helicopter, representative of an H-60, and a wing-only compound utility rotorcraft, representative of an H-60 with a wing similar to the X-49A wing. An explicit model following (EMF) control scheme is designed to achieve stability and desired rate command / attitude hold response around the roll, pitch, and yaw axes, while alleviating vibratory loads through both feed-forward and feedback compensation. The harmonic decomposition methodology is extended to enable optimization of primary flight control laws that mitigate vibratory loads. Specifically, linear time-periodic systems representative of the periodic rotorcraft dynamics are approximated by linear time-invariant (LTI) models. The LTI models are subsequently reduced and used in linear quadratic regulator (LQR) design to constrain the harmonics of the vibratory loads. Both fuselage state feedback and rotor state feedback are considered. A pseudo-inverse strategy is incorporated into the EMF scheme for redundant control allocation on the compound configuration. Simulations of the load alleviating controllers are compared to results from a baseline controller. Finally, an analysis is performed to assess the impact that load alleviating control action, rotor state feedback, and pseudo-inverse have on handling qualities in terms of ADS-33E specifications.

scholarly journals A Novel IGC Scheme for RHV with the Capabilities of Online Aerodynamic Coefficient Estimation and Trajectory Generation

Mathematics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 172
Author(s):  
Xueyun Wang ◽  
Yifan Li ◽  
Jingjuan Zhang
Keyword(s):  
Attitude Control ◽  
Unscented Kalman Filter ◽  
Sliding Mode ◽  
Trajectory Generation ◽  
Pseudospectral Method ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Aerodynamic Coefficient ◽  
Coefficient Estimation ◽  
Lift And Drag

A novel integrated guidance and control (IGC) scheme for a Re-entry Hypersonic Vehicle (RHV) is proposed with the capabilities of online aerodynamic coefficient estimation based on an Unscented Kalman Filter and online trajectory generation based on the Gaussian pseudospectral method. A linear quadratic regulator is adopted for trajectory tracking guidance and a second-layer sliding mode controller is designed for attitude control. The variation of lift and drag coefficients are modeled and estimated online, based on which a new trajectory can be generated. The commands of trajectory generation are set as moments of actuators and their extremums pose more constraints on the rate and acceleration of flow angles. Comprehensive simulations are conducted and comparable IGC performances with normal conditions are obtained under large aerodynamic coefficient errors according to online generated trajectory, which proves the effectiveness and advantages of the proposed IGC scheme.

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