Robust Control of a Gas Turbine With Variable Power Offtake

2006 ◽  
Author(s):  
Shahid Mahmood ◽  
Ian A. Griffin ◽  
Peter J. Fleming
Keyword(s):  
High Pressure ◽  
Robust Control ◽  
Gas Turbine ◽  
Disturbance Rejection ◽  
Closed Loop ◽  
Inverse Model ◽  
Conventional Approach ◽  
Control Performance ◽  
Variable Power ◽  
Improved Performance

The conventional approach to Rolls-Royce Inverse Model closed loop fuel control is to represent the inverse high-pressure (HP) spool dynamics within the controller. In this paper, the options of configuring the controller to represent either the intermediate (IP) or the low pressure (LP) dynamics of a 3-spool engine are also analysed. Control performance is assessed as the engine is subjected to step changes in power offtake. For each controller, power offtake is extracted from each of the three shafts in turn giving a total of 9 engine/controller configurations. For any given power offtake configuration applied to the engine, the results suggest that the controller based upon LP or IP dynamics offers more robustness measured in terms of phase margins and improved performance with regard to power offtake disturbance rejection.

A novel multivariable nonlinear robust control design for turbofan engines

2021 ◽  
pp. 014233122110396
Author(s):  
Dingding Cheng ◽  
Lijun Liu ◽  
Zhen Yu
Keyword(s):  
Robust Control ◽  
Closed Loop ◽  
Control Method ◽  
Operating Conditions ◽  
Large Region ◽  
Control Performance ◽  
Nonlinear Robust Control ◽  
Turbofan Engines ◽  
Robust Control Design ◽  
Nonlinear Robust

Traditional steady-state control methods are applied to turbofan engines operating in the small region near certain operating conditions, which need to switch controllers for operating in the large region and then may lead to instability and performance degradation of the closed-loop system. In this paper, a novel multivariable nonlinear robust control method for turbofan engines is proposed to improve the control performance within the large region. To enlarge the controllable region, a polynomial state-space model describes the nonlinear characteristics of turbofan engines. Based on the analysis of the closed-loop control system, by using the Lyapunov function theorems, a polynomial robust controller is designed to ensure the stability and desired nonlinear control performance of turbofan engines. Compared with the classical PI, mixed sensitivity, and H∞ control, simulation results show that the proposed method has better transient responses, disturbance rejection, and other control performance for the turbofan engine within the large region.

Inverse Model Control of a Three Spool Gas Turbine Engine

2005 ◽  
Author(s):  
Shahid Mahmood ◽  
Ian A. Griffin ◽  
Peter J. Fleming ◽  
Arthur J. Shutler
Keyword(s):  
Gas Turbine ◽  
Control Algorithm ◽  
Inverse Model ◽  
Turbine Engine ◽  
Design Procedures ◽  
Model Based ◽  
Model Control ◽  
Transient Control ◽  
Improved Performance ◽  
Gain Scheduled

The Rolls-Royce Inverse Model (RRIM) controller is a nonlinear, model-based fuel control algorithm. This paper compares the model-based design procedures and resulting performance of RRIM control to those of Classical Gain Scheduled (CGS) control for a three-spool gas turbine. It was observed that similar performance levels can be achieved using the RRIM with a significant decrease in tuning effort and design time when compared to CGS control. The RRIM controller also showed improved performance for the case of transient control. The paper indicates how and why the RRIM controller is robust across the operating envelope and highlights the practical advantages it affords to the industrial designer.

scholarly journals A NARX Model Reference Adaptive Control Scheme: Improved Disturbance Rejection Fractional-Order PID Control of an Experimental Magnetic Levitation System

Algorithms ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 201
Author(s):  
Hossein Alimohammadi ◽  
Baris Baykant Alagoz ◽  
Aleksei Tepljakov ◽  
Kristina Vassiljeva ◽  
Eduard Petlenkov
Keyword(s):  
Control System ◽  
Disturbance Rejection ◽  
Closed Loop ◽  
Control Structure ◽  
Magnetic Levitation ◽  
Reference Model ◽  
Control Performance ◽  
Control Loops ◽  
Model Reference Adaptive ◽  
Narx Model

Real control systems require robust control performance to deal with unpredictable and altering operating conditions of real-world systems. Improvement of disturbance rejection control performance should be considered as one of the essential control objectives in practical control system design tasks. This study presents a multi-loop Model Reference Adaptive Control (MRAC) scheme that leverages a nonlinear autoregressive neural network with external inputs (NARX) model in as the reference model. Authors observed that the performance of multi-loop MRAC-fractional-order proportional integral derivative (FOPID) control with MIT rule largely depends on the capability of the reference model to represent leading closed-loop dynamics of the experimental ML system. As such, the NARX model is used to represent disturbance-free dynamical behavior of PID control loop. It is remarkable that the obtained reference model is independent of the tuning of other control loops in the control system. The multi-loop MRAC-FOPID control structure detects impacts of disturbance incidents on control performance of the closed-loop FOPID control system and adapts the response of the FOPID control system to reduce the negative effects of the additive input disturbance. This multi-loop control structure deploys two specialized control loops: an inner loop, which is the closed-loop FOPID control system for stability and set-point control, and an outer loop, which involves a NARX reference model and an MIT rule to increase the adaptation ability of the system. Thus, the two-loop MRAC structure allows improvement of disturbance rejection performance without deteriorating precise set-point control and stability characteristics of the FOPID control loop. This is an important benefit of this control structure. To demonstrate disturbance rejection performance improvements of the proposed multi-loop MRAC-FOPID control with NARX model, an experimental study is conducted for disturbance rejection control of magnetic levitation test setup in the laboratory. Simulation and experimental results indicate an improvement of disturbance rejection performance.

scholarly journals Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Zaiyue Yang ◽  
C. W. Chan ◽  
Yiwen Wang
Keyword(s):  
Numerical Simulation ◽  
Robust Control ◽  
Nonlinear Systems ◽  
Finite Time ◽  
Closed Loop ◽  
Robust Stabilization ◽  
Control Coefficient ◽  
Control Performance ◽  
Stabilization Problem ◽  
Asymptotic Stabilization

This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.

Model Reference Adaptive Control Scheme for Retuning Method-Based Fractional-Order PID Control with Disturbance Rejection Applied to Closed-Loop Control of a Magnetic Levitation System

2018 ◽  
Vol 27 (11) ◽  
pp. 1850176 ◽  
Author(s):  
Aleksei Tepljakov ◽  
Baris Baykant Alagoz ◽  
Emmanuel Gonzalez ◽  
Eduard Petlenkov ◽  
Celaleddin Yeroglu
Keyword(s):  
Pid Control ◽  
Disturbance Rejection ◽  
Closed Loop ◽  
Magnetic Levitation ◽  
Control Performance ◽  
Control Loop ◽  
Loop Control ◽  
Disturbance Rejection Control ◽  
Fractional Order Pid ◽  
Model Reference Adaptive

This study demonstrates the utilization of model reference adaptive control (MRAC) for closed-loop fractional-order PID (FOPID) control of a magnetic levitation (ML) system. Design specifications of ML transportation systems require robust performance in the presence of environmental disturbances. Numerical and experimental results demonstrate that incorporation of MRAC and FOPID control can improve the disturbance rejection control performance of ML systems. The proposed multiloop MRAC–FOPID control structure is composed of two hierarchical loops which are working in conjunction to improve robust control performance of the system in case of disturbances and faults. In this multiloop approach, an inner loop performs a regular closed-loop FOPID control, and the outer loop performs MRAC based on Massachusetts Institute of Technology (MIT) rule. These loops are integrated by means of the input-shaping technique and therefore no modification of any parameter of the existing closed-loop control system is necessary. This property provides a straightforward design solution that allows for independent design of each loop. To implement FOPID control of the ML system, a retuning technique is used which allows transforming an existing PID control loop into an FOPID control loop. This paper presents the simulation and experimental results and discusses possible contributions of multiloop MRAC–FOPID structure to disturbance rejection control of the ML system.

Robust Control Method Based on Machine Learning for Boiler Combustion System

2014 ◽  
Vol 685 ◽  
pp. 368-372 ◽  
Author(s):  
Hao Zhang ◽  
Ya Jie Zhang ◽  
Yan Gu Zhang
Keyword(s):  
Robust Control ◽  
Intelligent Control ◽  
Pid Control ◽  
Control Algorithm ◽  
Control Method ◽  
Support Vector ◽  
Control Performance ◽  
Fuzzy Pid Control ◽  
On Line ◽  
Control Output

In this study, we presented a boiler combustion robust control method under load changes based on the least squares support vector machine, PID parameters are on-line adjusted and identified by LSSVM, optimum control output is obtained. The simulation result shows control performance of the intelligent control algorithm is superior to traditional control algorithm and fuzzy PID control algorithm, the study provides a new control method for strong non-linear boiler combustion control system.

scholarly journals Measurement and Process Control in Precision Hot Embossing

2013 ◽  
Author(s):  
Maia R. Bageant ◽  
David E. Hardt
Keyword(s):  
Process Control ◽  
Material Properties ◽  
Disturbance Rejection ◽  
Closed Loop ◽  
Hot Embossing ◽  
Commercial Production ◽  
Bulk Deformation ◽  
Functional Tests ◽  
Medical Field ◽  
High Degree

Microfluidic technologies hold a great deal of promise in advancing the medical field, but transitioning them from research to commercial production has proven problematic. We propose precision hot embossing as a process to produce high volumes of devices with low capital cost and a high degree of flexibility. Hot embossing has not been widely applied to precision forming of hard polymers at viable production rates. To this end we have developed experimental equipment capable of maintaining the necessary precision in forming parameters while minimizing cycle time. In addition, since equipment precision alone does not guarantee consistent product quality, our work also focuses on real-time sensing and diagnosis of the process. This paper covers both the basic details for a novel embossing machine, and the utilization of the force and displacement data acquired during the embossing cycle to diagnose the state of the material and process. The precision necessary in both the forming machine and the instrumentation will be covered in detail. It will be shown that variation in the material properties (e.g. thickness, glass transition temperature) as well as the degree of bulk deformation of the substrate can be detected from these measurements. If these data are correlated with subsequent downstream functional tests, a total measure of quality may be determined and used to apply closed-loop cycle-to-cycle control to the entire process. By incorporating automation and specialized precision equipment into a tabletop “microfactory” setting, we aim to demonstrate a high degree of process control and disturbance rejection for the process of hot embossing as applied at the micron scale.

Conjugate Heat Transfer Analysis of a High Pressure Air-Cooled Gas Turbine Vane

2010 ◽  
Author(s):  
Zhenfeng Wang ◽  
Peigang Yan ◽  
Hongyan Huang ◽  
Wanjin Han
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Boundary Conditions ◽  
Gas Turbine ◽  
Turbulence Model ◽  
Conjugate Heat Transfer ◽  
Suction Side ◽  
Turbulence Characteristic ◽  
Transition Flow ◽  
Characteristic Boundary

The ANSYS-CFX software is used to simulate NASA-Mark II high pressure air-cooled gas turbine. The work condition is Run 5411 which have transition flow characteristics. The different turbulence models are adopted to solve conjugate heat transfer problem of this three-dimensional turbine blade. Comparing to the experimental results, k-ω-SST-γ-θ turbulence model results are more accurate and can simulate accurately the flow and heat transfer characteristics of turbine with transition flow characteristics. But k-ω-SST-γ-θ turbulence model overestimates the turbulence kinetic energy of blade local region and makes the heat transfer coefficient higher. It causes that local region temperature of suction side is higher. In this paper, the compiled code adopts the B-L algebra model and simulates the same computation model. The results show that the results of B-L model are accurate besides it has 4% temperature error in the suction side transition region. In addition, different turbulence characteristic boundary conditions of turbine inner-cooling passages are given and K-ω-SST-γ-θ turbulence model is adopted in order to obtain the effect of turbulence characteristic boundary conditions for the conjugate heat transfer computation results. The results show that the turbulence characteristic boundary conditions of turbine inner-cooling passages have a great effect on the conjugate heat transfer results of high pressure gas turbine. ANSYS is applied to analysis the thermal stress of Mark II blade which has ten radial cooled passages and the results of Von Mises stress show that the temperature gradient results have a great effect on the results of blade thermal stress.

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