Mostafa Abdel-Geliel

Application of model predictive control for fault tolerant system using dynamic safety margin

Model predictive control (MPC) has the ability to cope with hard constraints on control and state. It has, therefore, been widely applied in most industries specially, petrochemical industries. Dynamic safety margin (DSM) is a performance index used to measure the distance between a predefined safety boundary, described by a set of inequality constraints, in state space and system trajectory as it evolves. Designing MPC based on DSM is especially important for safety critical system to maintain a predefined margin of safety during transient and steady state. In this work, MPC based on DSM is used in fault tolerant control (FTC) design. The proposed method of FTC is suitable for single and multi-model system according to the fault type and fault information. It can compensate missed information about the fault and uncertainties in the faulty model

Dynamic safety margin principle and application in control of safety critical systems

Control systems are designed in general to meet a given performance requirement. Dynamic safety margin (DSM) is a new performance index used to measure the distance between a predefined safety boundary in the state space and the system trajectory as it evolves. Controller design based on DSM is especially important for safety-critical systems to maintain a predefined margin of safety during the transient and in the presence of large disturbances. In this paper, the idea of DSM is explained and applied in controller design for fluid level in two-tank system. Simulation examples and results of a real-time implementation on the actual process demonstrate the fruitfulness of this design.

Application of Dynamic Safety Margin in robust fault detection and fault tolerant control

The Dynamic Safety Margin (DSM) is defined as a performance index, whose independent variable is the distance from a predefined safety boundary, which is described in the state space by a set of inequality constraints, to the current system state. Robustness is an important issue for fault detection and isolation (FDI) system. In this work, design a robust FDI system based on DSM is applied. The fault is detected based on the analysis of DSM and isolated using a multi-model approach. The main properties of the suggested FDI system is discussed and the main limitation as well. The design of a controller based on DSM is useful to maintain a predefined margin of safety during the transient phase of the system or when disturbances are present. Therefore, the application of DSM in fault tolerant control (FTC) design using in particular model predictive control (MPC) is discussed. The fruitiness of the proposed FDI system and FTC is illustrated by real-time implementation.

Dynamic safety margin in fault-tolerant predictive controller

Dynamic safety margin (DSM) is a new performance index used to measure the distance between a predefined safety boundary in the state space and the system trajectory as it evolves. Controller design based on DSM is important to maintain a predefined margin of safety during the transient and in the presence of large disturbances particularly in safety-critical systems. In this paper, a fault tolerant control design, using predictive controller based on DSM, to recover system performance after some system faults is discussed. In addition, real-time results of a control system, which was implemented in a two-tank system, are presented to demonstrate the fruitfulness of this design

Adaptive controller using dynamic safety margin for hybrid laboratory plant

A large disturbance or model parameters variation in controlled systems may lead to system failure and decrease system safety. Adapting controller parameters is essential to compensate the system disturbance or model uncertainties. In this work, controller parameters have been adapted based on the dynamic safety margin (DSM) index to increase the system safety during different operation condition. Fuzzy controller is used to supervise DSM and to adapt the controller parameters. Also predictive controller based on DSM is discussed. The real time implementation for adaptive controller based on DSM is tested on a hybrid laboratory plant.

Controller design and adaptation based on Dynamic Safety Margin

Most of the real processes have state and control constraints. Design a control system, which achieve the required performance in addition to avoiding the constraints violation, is an essential demand. The dynamic safety margin (DSM) is an index used to indicate the system constraints achievements and used also as a measure for the violation of constraints. The design of a controller based on DSM is useful to maintain a predefined margin of safety during the transient phase of the system or when disturbances or faults are present. In this paper, the conditions to select controller parameters in order to satisfy DSM constraints are discussed. Moreover, Using the DSM as a performance index to adapt controller parameters, in particular PID controller is proposed. The difference between the proposed design techniques is illustrated using a simulation example.

Adaptive PID controller based on model predictive control

Model Predictive Control (MPC) is very suitable controller for many industrial applications especially for constrained systems. However, it requires high computation burden. On the other side, PID controller is simple and popular for industrial applications in particular for Single Input Single Output (SISO) systems but it is difficult to be tuned especially for constrained systems. To gain the benefits of the two controllers and reduce their limitations, a hierarchical control structure (two levels) is proposed. The algorithm concept focuses on the adaptation of PID controller parameters (lower level) according to the MPC performance (higher level). The algorithm is tested on two constrained systems; separately excited DC motor as a SISO system and three tank system as Multi Input Multi Output (MIMO) benchmark system.

Realization of adaptable PID controller within an industrial automated system

This paper describes and implements an a real control technique using advanced automation technology. PID controller is one of the most controller used in industrial but it need to be adaptable in real situation in order to overcome the parameter variation and system disturbance. An adaptable PID controller based on analogical gate technique is implemented using an industrial Programmable Logic Controller (PLC) to control the temperature of a process by actuating of a three way valve. The valve distributes the hot and cooled air in order to adjust the temperature of a vessel. The system control hardware consists of first; PLC as a field controller with high sampling rates, second; Human Machine Interface (HMI) as a local operating and adjusting station, finally; SCADA software to adjust and supervise the overall system. The process parameter estimation, simulation results and practical results are obtained and compared for system validation. A comparison between conventional and the proposed adaptable one performance is introduced, showing merits and effectiveness of proposed algorithm.

Modeling and simulation of a hybrid power generation system of wind turbine, micro-turbine and solar heater cells

This paper is devoted to study the conversion of renewable energy resources into electrical energy in a standalone hybrid power generation system. The hybrid system consists of a 230 kW wind turbine, a 30 kW micro-turbine and solar heaters of double-parallel flow. Solar heaters are being used to partially preheat the air entering the combustion chamber of the micro-turbine in order to decrease the amount of fuel consumption. The dynamic behavior and simulation results are being discussed to extract the maximum energy obtained from a variable speed wind power generation system. The hybrid model has been simulated under several wind speed conditions. A supervisory controller is designed that was able to manage between the maximum energy captured from the wind turbine and the generated energy by the microturbine to meet the load demands and wind power fluctuation due to wind speed variation. Solar heaters saved amount of fuel on average 15.4 U.S. Dollars/hr monthly according to the data provided in the year 2013.

Simulation of ship maneuvering behavior based on the modular mathematical model

With the rapid development of the computer technology and its successful application in ship engineering, the method of computer simulation based on the mathematical models became more and more popular; it provides a convenient tool for predicting ship maneuverability. One of the preconditions for applying that is the modeling of the dynamic differential equations that represent the ship dynamics in three degrees of freedom. The effectiveness of simulation is guaranteed by how accurate the model is. There are different types of ship mathematical modeling. In this work, the ship modular mathematical model was investigated. Simulink software was utilized to develop the ship subsystems as individual modules. Modules hydrodynamic forces, and moments were implemented in simulating the ship maneuvering behaviors of the ESSO OSAKA tanker class ship. Moreover, different types of maneuvering are tested in particular, turning and zigzag motion.