scholarly journals Dynamic modelling and linear quadratic Gaussian control of a twin-rotor multi-input multi-output system

2003 ◽  
Vol 217 (3) ◽  
pp. 203-227 ◽  
Author(s):  
S M Ahmad ◽  
A J Chipperfield ◽  
M O Tokhi
Keyword(s):  
Mimo System ◽  
Dynamic Modelling ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Control Effort ◽  
Stability Augmentation ◽  
Identification Technique ◽  
High Control ◽  
And Control ◽  
Twin Rotor

This paper presents an investigation into the modelling and control of a one-degree-of-freedom (1 DOF) twin-rotor multi-input multi-output (MIMO) system (TRMS). The behaviour of the TRMS in certain aspects resembles that of a helicopter. Hence, it is an interesting identification and control problem. A dynamic model characterizing the TRMS in hover is extracted using a black-box system identification technique. The extracted model is employed in the design of a feedback linear quadratic Gaussian compensator, namely the stability augmentation system (SAS). This has a good tracking capability but requires high control effort and has inadequate authority over residual vibration of the system. These problems are resolved by further augmenting the system with a command path prefilter, resulting in the command and stability augmentation system (CSAS). The combined feedforward and feedback compensator satisfies the performance objectives and obeys the actuator constraint. The control law is implemented in realtime on the TRMS platform.

scholarly journals Parametric modelling and dynamic characterization of a two-degree-of-freedom twin-rotor multi-input multi-output system

2001 ◽  
Vol 215 (2) ◽  
pp. 63-78 ◽  
Author(s):  
S M Ahmad ◽  
A J Chipperfield ◽  
M O Tokhi
Keyword(s):  
Mimo System ◽  
Degree Of Freedom ◽  
Parametric Modelling ◽  
Dynamic Characterization ◽  
Identification Technique ◽  
New Generation ◽  
And Control ◽  
Two Degree Of Freedom ◽  
Twin Rotor

A mathematical model for the dynamic characterization of a two-degree-of-freedom (2 DOF) twin-rotor multi-input multi-output (MIMO) system (TRMS) in hover is extracted using a black box system identification technique. The behaviour of the TRMS, in certain aspects, resembles that of a helicopter, with a significant cross-coupling between longitudinal and lateral directional motions. Hence, it is an interesting identification and control problem. Identification for a 2 DOF, rigid-body, discrete-time linear model is presented in detail. The extracted model has a good degree of prediction capability. The modelling approach presented is suitable for complex new-generation air vehicles.

An LQ Approach to Active Control of Vibrations in Helicopters

1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Linear Quadratic ◽  
Control Effort ◽  
Vibration Effect ◽  
Suitable Definition ◽  
Lq Optimal Control ◽  
The One ◽  
Definition Of ◽  
And Control

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.

scholarly journals Control Design and Validation for Floating Piston Electro-Pneumatic Gearbox Actuator

2020 ◽  
Vol 10 (10) ◽  
pp. 3514 ◽  
Author(s):  
Adam Szabo ◽  
Tamas Becsi ◽  
Peter Gaspar
Keyword(s):  
Piecewise Linear ◽  
Control Design ◽  
Continuous Control ◽  
Control Methods ◽  
Linear Quadratic ◽  
Modeling And Control ◽  
Control Frequency ◽  
Heavy Duty Vehicle ◽  
High Control ◽  
And Control

The paper presents the modeling and control design of a floating piston electro-pneumatic gearbox actuator and, moreover, the industrial validation of the controller system. As part of a heavy-duty vehicle, it needs to meet strict and contradictory requirements and units applying the system with different supply pressures in order to operate under various environmental conditions. Because of the high control frequency domain of the real system, post-modern control methods with high computational demands could not be used as they do not meet real-time requirements on automotive level. During the modeling phase, the essential simplifications are shown with the awareness of the trade-off between calculation speed and numerical accuracy to generate a multi-state piecewise-linear system. Two LTI control methods are introduced, i.e., a PD and an Linear-Quadratic Regulators (LQR) solution, in which the continuous control signals are transformed into discrete voltage solenoid commands for the valves. The validation of both the model and the control system are performed on a real physical implementation. The results show that both modeling and control design are suitable for the control tasks using floating piston cylinders and, moreover, these methods can be extended to electro-pneumatic cylinders with different layouts.

LQG Control Design for Vehicle Active Anti-Roll Bar System

2014 ◽  
Vol 663 ◽  
pp. 146-151 ◽  
Author(s):  
Noraishikin Zulkarnain ◽  
Hairi Zamzuri ◽  
Saiful Amri Mazlan
Keyword(s):  
Ride Comfort ◽  
Simulation Analysis ◽  
Control Strategies ◽  
Dynamic Modelling ◽  
Linear Quadratic Regulator ◽  
Vehicle Body ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Roll Rate ◽  
External Forces

The objective of this paper is to design a linear quadratic regulator (LQR) and linear quadratic Gaussian (LQG) controllers for an active anti-roll bar system. The use of an active anti-roll bar will be analysed from two different perspectives in vehicle ride comfort and handling performances. This paper proposed the basic vehicle dynamic modelling with four degree of freedom (DOF) on half car model and are described that show, why and how it is possible to control the handling and ride comfort of the car, with the external forces also control strategies on the front anti-roll bar. By simulation analysis, the design model is validity and the performance under control of linear quadratic regulator (LQR) and linear quadratic Gaussian (LQG) controller are achieved. Both two controllers are modeled in MATLAB/SIMULINK environment. It has to be determined which control strategy delivers better performance with respect to roll angle and the roll rate of half vehicle body. The result shows, however, that LQG produced better response compared to a LQR strategy.

Microclimate control of a greenhouse by adaptive Generalized Linear Quadratic strategy

2018 ◽  
Vol 11 (1) ◽  
pp. 377 ◽  
Author(s):  
Mohamed Essahafi ◽  
Mustapha Ait Lafkih
Keyword(s):  
Optimal Control ◽  
Least Squares ◽  
Recursive Least Squares ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Advanced Technique ◽  
Online Identification ◽  
State Models ◽  
The Cost ◽  
And Control

<p>To highlight the conceptual aspects related to the implementation of techniques optimal control in the form state, we present in this paper, the identification and control of the temperature and humidity of the air inside a greenhouse. Using respectively an online identification based on the recursive least squares with forgotten Factor method and the multivariable adaptive linear quadratic Gaussian approach which the advanced technique (LQG) is presented.  The design of this controller parameters is based on state models identified directly from measured greenhouse data. hence the performances of the controller developed are illustrated by different tests and simulations on identified models of a greenhouse. Discussions on the results obtained are then processed in the paper to show the effectiveness of the controller in terms of stability and optimization of the cost of control.</p>

scholarly journals Dynamic modelling and open-loop control of a twin rotor multi-input multi-output system

2002 ◽  
Vol 216 (6) ◽  
pp. 477-496 ◽  
Author(s):  
S M Ahmad ◽  
A J Chipperfield ◽  
M O Tokhi
Keyword(s):  
Mimo System ◽  
Dynamic Modelling ◽  
Open Loop ◽  
Open Loop Control ◽  
Performance Study ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Loop Control ◽  
Low Pass ◽  
Twin Rotor

A dynamic model for a one-degree-of-freedom (DOF) twin rotor multi-input multi-output (MIMO) system (TRMS) in hover is obtained using a black-box system identification technique. The behaviour of the TRMS in certain aspects resembles that of a helicopter; hence, it is an interesting identification and control problem. This paper investigates modelling and open-loop control of the longitudinal axis alone, while the lateral axis movement is physically constrained. It is argued that some aspects of the modelling approach presented are suitable for a class of new generation or innovative air vehicles with complex dynamics. The extracted model is employed for designing and implementing a feedforward/open-loop control. Open-loop control is often the preliminary step for development of more complex feedback control laws. Open-loop control strategies using shaped command inputs are accordingly investigated for resonance suppression in the TRMS. Digital low-pass and band-stop filter shaped inputs are used on the TRMS testbed, based on the identified vibrational modes. A comparative performance study is carried out and the corresponding results presented. The low-pass filter is shown to result in better vibration reduction.

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