scholarly journals Time-Domain Simulation of Multibody Floating Systems Based on State-Space Modeling Technology

2011 ◽  
Author(s):  
Xiaochuan Yu ◽  
Jeffrey M. Falzarano
Keyword(s):  
State Space ◽  
Time Domain ◽  
Numerical Study ◽  
Equations Of Motion ◽  
Impulse Response Function ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Motion Responses ◽  
Space Modeling ◽  
Floating System

It is important to study MULTIBODY dynamics when analyzing the transfer of cargo between ships and platforms at sea. The hydrodynamic interactions between multiple bodies in close proximity are expected to be significant and complex. In this paper, two levels of approximation of hydrodynamic coefficients are considered, i.e., the constant coefficient method (CCM) and the impulse response function (IRF). The equations of motion are written in standard state-space format, in which the convolution terms are computed using the trapezoidal rule. Initially, this newly proposed numerical scheme is successfully applied to calculate motion responses of a two-body floating system. The time-domain responses of this multibody floating system in both regular waves and random sea are further verified numerically. In addition, an ideal case of the motion mitigation of this system using Dynamic Positioning (DP) system is also given and discussed. The mean drift force is considered using Newman’s approximation. Numerical study shows that the optimal Linear Quadratic Regulator (LQR) method can help to mitigate the motion responses of this two-body floating system at sea. Finally, this scheme is extended to a three-body floating system, with the relative motions in random seas determined.

scholarly journals A Model and State-Space Controllers for an Intercooled, Regenerated (ICR) Gas Turbine Engine

1992 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
R. W. Garman
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
High Efficiency ◽  
Linear Quadratic Regulator ◽  
Gas Turbine Engine ◽  
Linear Quadratic ◽  
Turbine Engine ◽  
Simulation Language ◽  
Linear State ◽  
High Level

A two-and-one-half spool gas turbine engine was modeled using the Advanced Computer Simulation Language (ACSL), a high level simulation environment based on FORTRAN. A possible future high efficiency engine for powering naval ships is an intercooled, regenerated (ICR) gas turbine engine and these features were incorporated into the model. Utilizing sophisticated instructions available in ACSL linear state-space models for this engine were obtained. A high level engineering computational language, MATLAB, was employed to exercise these models to obtain optimal feedback controllers characterized by the following methods: (1) state feedback; (2) linear quadratic regulator (LQR) theory; and (3) polygonal search. The methods were compared by examining the transient curves for a fixed off-load, and on-load profile.

FULL-AND REDUCED- ORDER COMPENSATOR FOR INNOSAT ATTITUDE CONTROL

2015 ◽  
Vol 76 (12) ◽  
Author(s):  
Fadzilah Hashim ◽  
Mohd Yusoff Mashor ◽  
Siti Maryam Sharun
Keyword(s):  
State Space ◽  
Attitude Control ◽  
Space Form ◽  
Transfer Functions ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Reduced Order ◽  
Lqr Control ◽  
Best Value ◽  
Control Scheme

This paper presents a study on the estimator based on Linear Quadratic Regulator (LQR) control scheme for Innovative Satellite (InnoSAT). By using LQR control scheme, the controller and the estimator has been derived for state space form in all three axes to stabilize the system’s performance. This study starts by converting the transfer functions of attitude control into state space form.  Then, the step continues by finding the best value of weighting matrices of LQR in order to obtain the best value of controller gain, K. After that, the best value of L is obtained for the estimator gain. The value of K and L is combined in forming full order compensator and in the same time the reduced order compensator is also formed. Lastly, the performance of full order compensator is compared to reduced order compensator. From the simulation, results indicate that both types of estimators have presented good stability and tracking performance. However, reduced order estimator has simpler equation and faster convergence to zero than the full order estimator. This property is very important in developing a satellite attitude control for real-time implementation.

THE EVALUATION OF CONTROLLER TRACKING PERFORMANCE BASED ON TAYLOR’S SERIES EXPANSION MODEL

2015 ◽  
Vol 74 (9) ◽  
Author(s):  
Maziyah Mat Noh ◽  
M. R. Arshad ◽  
Rosmiwati Mohd-Mokhtar
Keyword(s):  
Series Expansion ◽  
Sliding Mode ◽  
Equations Of Motion ◽  
Linear Quadratic Regulator ◽  
Tracking Performance ◽  
Convergence Time ◽  
Linear Quadratic ◽  
Glide Path ◽  
Expansion Model ◽  
Taylor’S Series

This paper presents the controller tracking performance of Underwater Glider. The controllers are designed based on linearised model. The equations of motion are restricted to longitudinal plane. The controllers are designed and tested for the glide path moving from 45° to 30° downward and upward. The model is linearised using Taylor’s series expansion linearisation method. The controller developed here is Sliding Mode Control (SMC), and Linear Quadratic Regulator (LQR). The performance of both controllers are compared and analysed. The simulations show SMC produce better performance with about over 30% faster than LQR based its convergence time.

scholarly journals Trajectory Tracking and Stabilization of a Quadrotor Using Model Predictive Control of Laguerre Functions

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Mapopa Chipofya ◽  
Deok Jin Lee ◽  
Kil To Chong
Keyword(s):  
State Space ◽  
Predictive Control ◽  
Trajectory Tracking ◽  
Linear Quadratic Regulator ◽  
Laguerre Functions ◽  
Linear Quadratic ◽  
Model Predictive Controller ◽  
Predictive Controller ◽  
Linear State ◽  
Quadrotor System

This paper presents a solution to stability and trajectory tracking of a quadrotor system using a model predictive controller designed using a type of orthonormal functions called Laguerre functions. A linear model of the quadrotor is derived and used. To check the performance of the controller we compare it with a linear quadratic regulator and a more traditional linear state space MPC. Simulations for trajectory tracking and stability are performed in MATLAB and results provided in this paper.

Dynamic Modeling and Vibration Control of a Space Flexible Manipulator Using Piezoelectric Actuators and Sensors

2011 ◽  
Vol 345 ◽  
pp. 46-52 ◽  
Author(s):  
Jun Qiang Lou ◽  
Yan Ding Wei
Keyword(s):  
Vibration Control ◽  
Dynamic Modeling ◽  
Vibration Suppression ◽  
Equations Of Motion ◽  
Linear Quadratic Regulator ◽  
Flexible Manipulator ◽  
Coupled Vibration ◽  
Linear Quadratic ◽  
Space Manipulator ◽  
Tip Mass

This paper concerns the dynamic modeling and vibration control of a space two-link flexible manipulator. Two types of PZT actuators, PZT shear actuator and torsional actuator, are used to suppress the bending-torsional-coupled vibration of the space manipulator. Using extended Hamilton’s principle and the finite element method, equations of motion of the space flexible manipulator with PZT actuators and tip mass are obtained. Based on modal analyze theory, the state space model of the system is then used to design the control system. A linear quadratic regulator (LQR) controller is designed to achieve vibration suppression of the space manipulator system. From the numerical results, we can get that the proposed controller has a suitable and efficient performance suppressing the bending-torsional-coupled vibration of the space two-link flexible manipulator.

scholarly journals KONTROL SUDUT ATTITUDE MENGGUNAKAN LINEAR QUADRATIC REGULATOR (LQR) UNTUK QUADROTOR DENGAN PAYLOAD

ROTASI ◽  
2013 ◽  
Vol 15 (4) ◽  
pp. 16 ◽  
Author(s):  
Mochammad Ariyanto ◽  
Joga Dharma Setiawan ◽  
Ismoyo Haryanto
Keyword(s):  
Steady State ◽  
State Space ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Aerial Manipulation ◽  
Step Input ◽  
Object Interaction ◽  
Integral Action ◽  
Linear State ◽  
State Error

Quadrotor telah dikembangkan oleh peneliti di dunia ini sebagai aerial object interaction/aerial manipulation. Agar quadrotor bisa terbang mengangkat beban, maka dibutuhkan sistem kontrol yang dapat mengkompensasi perubahan pusat gravitasi. Pada penelitian ini, model matematika quadrotor dengan efek beban/payload akan dikembangkan. Untuk mengkompensasi perubahan lokasi pusat gravitasi karena efek beban, Linear Quadratic Regulator (LQR) akan digunakan untuk stabilisasi sudut Euler.Model linear state space dihitung menggunakan persmaan gerak onlinear quadrotor tanpa beban, kemudian disintesis sistem kontrol   LQR. Kontrol tersebut diterapkan dalam model matematika nonlinear dengan beban/payload. Berdasarkan hasil simulasi integral action dari kontrol LQR dapat menghilangkan steady state error setelah diberikan step input, dan kondisi sudut awal sebesar 50. Variasi beban dari 0 gr sampai dengan 200 gr tidak akan memberikan steady state error

scholarly journals Control for the Space Tether System Motion

2020 ◽  
pp. 106-116
Author(s):  
Maria Cecilia Zanardi ◽  
Paola da Rosa Prado ◽  
Leandro Baroni
Keyword(s):  
State Feedback ◽  
Equations Of Motion ◽  
Orbital Plane ◽  
Linear Quadratic Regulator ◽  
Effective Control ◽  
Feedback Gain ◽  
Second Variation ◽  
Linear Quadratic ◽  
Space Tether ◽  
The Second Variation

This paper proposed a study of a spatial tether system (STS), composed by two satellite (a main satellite and a subsatellite), with the objective of developing a control system in which the motion of the subsatellite is limited in the orbital plane of the main satellite. The linear quadratic regulator (LQR) method is used to implement this control, which is an optimal control with state feedback to predict the linearization of the equations of motion to calculate the feedback gain, using the resolution of Riccati equation. The results show an effective control, with the motion of the subsatellite limited only to the stretch of the cable that links both satellites. However, it is necessary to introduce an auxiliary torque, since the linearized equation associated with the second variation of the angle out of the plan does not have a term independent of the state vector.

Minimizing Human Tracking Error for Robotic Rehabilitation Device

2015 ◽  
Vol 9 (4) ◽  
Author(s):  
Andrew J. Homich ◽  
Megan A. Doerzbacher ◽  
Eric L. Tschantz ◽  
Stephen J. Piazza ◽  
Everett C. Hills ◽  
...  
Keyword(s):  
State Space ◽  
Tracking Error ◽  
Linear Quadratic Regulator ◽  
Gait Training ◽  
Average Error ◽  
Linear Quadratic ◽  
Optimal State ◽  
Filter Performance ◽  
Complementary Filter ◽  
Angular Velocities

This paper explores the design of a novel robotic device for gait training and rehabilitation, a method to estimate a human's orientation within the rehabilitation device, as well as an optimal state space controller to actuate the rehabilitation device. The robotic parallel bars (RPBs) were designed to address the shortcomings of currently available assistive devices. The RPB device moves in response to a human occupant to maintain a constant distance and orientation to the human. To minimize the error in tracking the human, a complementary filter was optimized to estimate the human's orientation within the device using a magnetometer and gyroscope. Experimental measurements of complementary filter performance on a test platform show that the filter estimates orientation with an average error of 0.62 deg over a range of angular velocities from 22.5 deg/s to 180 deg/s. The RPB device response was simulated, and an optimal state space controller was implemented using a linear quadratic regulator (LQR). The controller has an average position error of 14.1 cm and an average orientation error of 14.3 deg when tracking a human, while the simulation predicted an average error of 10.5 cm and 5.6 deg. The achieved level of accuracy in following a human user is sufficiently sensitive for the RPB device to conduct more advanced, realistic gait training and rehabilitation techniques for mobility impaired patients able to safely support their body weight with their legs and arms.

Experimental and Numerical Studies on Ship Motion Responses Coupled with Sloshing in Waves

2009 ◽  
Vol 53 (02) ◽  
pp. 68-82 ◽  
Author(s):  
Bo-Woo Nam ◽  
Yonghwan Kim ◽  
Dae-Woong Kim ◽  
Yong-Soo Kim
Keyword(s):  
Numerical Study ◽  
Experimental Studies ◽  
Impulse Response Function ◽  
Ship Motion ◽  
Computational Results ◽  
Floating Bodies ◽  
Motion Responses ◽  
Significant Difference ◽  
Response Amplitude Operators ◽  
Liquid Natural Gas

This study considers the motion responses of floating bodies in waves coupled with sloshing-induced internal forces and their effects on sloshing-induced impact loads. The linear ship motion is solved using an impulse-response-function (IRF) method, while the nonlinear sloshing flow is simulated using a finite difference method. The considered models are a liquid natural gas floating production, storage, and offloading unit (LNG FPSO) with two partially filled tanks and a modified S175 hull with an antirolling tank. In the case of the LNG FPSO model, both numerical and experimental studies are carried out. Three degree-of-freedom motion responses are allowed in the presence of regular waves, and the measured response amplitude operators (RAOs) are compared with computational results. For the modified S175 hull, the computational results are compared with other existing computational results. It is observed that the present method provides a fair agreement with experimental and other numerical results, showing significant coupling effects on both motion responses and sloshing flows. The numerical study extends to the observation of pressure field inside the tanks, and a significant difference in internal pressure is also shown.

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