Ibrahim Beklan Kucukdemiral

LPV gain-scheduling controller design for a non-linear quarter-vehicle active suspension system

There always exists a conflict between ride comfort and suspension deflection performances during the vibration control of suspension systems. Active suspension control systems, which are designed by linear methods, can only serve as a trade-off between these conflicting performance criteria. Both performance objectives can only be accomplished at the same time by using a nonlinear controller. This paper addresses the non-linear induced L2 control of an active suspension system, which contains non-linear spring and damper elements. The design method is based on the linear parameter varying (LPV) model of the system. The proposed method utilizes the bilinear damping characteristic, stiffening spring characteristic when the suspension deflection approaches the structural limits, mass variations and parameter-dependent weighting filters. Simulation studies both in time and frequency domain demonstrate that the active suspension system controlled by the proposed method always guarantees an agreement between acceleration (comfort) and suspension deflection magnitudes together with a high ride performance.

Receding horizon H ∞ control of time-delay systems

This paper deals with the disturbance rejection problem for discrete-time linear systems having time-varying state delays and control constraints. The study proposes a novel receding horizon H∞ control method utilizing a linear matrix inequality based optimization algorithm which is solved in each step of run-time. The proposed controller attenuates disturbances having bounded energies on controlled output and ensures the closed-loop stability and dissipation while meeting the physical control input constraints. The originality of the work lies on the extension of the idea of the well-known H∞ receding horizon control technique developed for linear discrete-time systems to interval time-delay systems having time-varying delays. The efficiency of the proposed method is illustrated through simulation studies that are carried out on a couple of benchmark problems.

A robust PID like state-feedback control via LMI approach: An application on a Double Inverted Pendulum System

This paper addresses the design method for robust PID like controllers which guarantee the quadratic stability, performance in terms of H2 and Hinfin specifications, pole locations and maximum output control. The approach is based on the transformation of the PID controller design problem to that of state feedback controller design thereby the convex optimization approaches can be adapted. Real time experimental results on a double inverted pendulum system demonstrates the validity and applicability of the proposed approach.

Adaptive Self-Tuning Control of Robot Manipulators with Periodic Disturbance Estimation

This paper addresses the problem of position tracking control of robot manipulators in the presence of parametric uncertainty and additive periodic disturbances. Specifically, a self tuning, Lyapunov-based adaptive controller with desired dynamics compensation term and a disturbance estimator has been designed to ensure that the link position tracking error converges to zero asymptotically, despite the partially linearly parametrizable robot dynamics. Extensive experimental results are provided to illustrate the viability and performance of the proposed controller.

Formalization of a novel sugeno type adaptive fuzzy sliding mode controller for a class of nonlinear systems

Formalization of a novel robust adaptive Sugeno based fuzzy sliding mode controller equipped with a supervisory controller is considered for the control of a class of nonlinear systems which significantly reduce computation via reducing the size of fuzzy rule base. Besides, all the system parameters such as control and state signals can be confined in a predefined bounded region by use of proposed control method. The proposed method does not need any information of the controlled plant and expertise

A robust single input adaptive sliding mode fuzzy logic controller for automotive active suspension system

The proposed controller in this paper, which combines the capability of fuzzy logic with the robustness of sliding mode controller, presents prevailing results with its adaptive architecture and proves to overcome the global stability problem of the control of nonlinear systems. Effectiveness of the controller and the performance comparison are demonstrated with chosen control techniques including PID and PD type self-tuning fuzzy controller on a quarter car model which consists of component-wise nonlinearities.

Robust Moving Horizon Control of Discrete Time-Delayed Systems with Interval Time-Varying Delays

In this study, design of a delay-dependent type moving horizon state-feedback control (MHHC) is considered for a class of linear discrete-time system subject to time-varying state delays, norm-bounded uncertainties, and disturbances with bounded energies. The closed-loop robust stability and robust performance problems are considered to overcome the instability and poor disturbance rejection performance due to the existence of parametric uncertainties and time-delay appeared in the system dynamics. Utilizing a discrete-time Lyapunov-Krasovskii functional, some delay-dependent linear matrix inequality (LMI) based conditions are provided. It is shown that if one can find a feasible solution set for these LMI conditions iteratively at each step of run-time, then we can construct a control law which guarantees the closed-loop asymptotic stability, maximum disturbance rejection performance, and closed-loop dissipativity in view of the actuator limitations. Two numerical examples with simulations on a nominal and uncertain discrete-time, time-delayed systems, are presented at the end, in order to demonstrate the efficiency of the proposed method.

A stewart platform as a FBW flight control unit for space vehicles

A variety of flight control units have been put into realization for navigational purposes of spatially moving vehicles, which is mostly manipulated by 2–3 degrees-of-freedom (DOF) joysticks. Since motion in space consists of three translational motions in forward, side and vertical directions and three rotational motions about these axis; with present joystick interfaces, spatial vehicles has to employ more than one navigational control unit to be able to navigate on all required directions. In this study, a 3×3 Stewart-Platform-based FBW (Fly-By-Wire) flight control unit with force feedback is presented which will provide single point manipulation of any space vehicle performing spatial motions along three translational and three rotational axis. Within the frame of this paper, design, capability and the advantages of the novel system is mentioned. Kinematics of the Stewart Platform (SP) mechanism employed and its motion potentials is presented by simulations and workspace of the system is evaluated. Dynamic analysis by Bond-Graph approach will be mentioned. Mechatronic design of the complete structure is discussed and force reflection capability of the system with simulations is pointed out using stiffness control. Finally, the possible future work of the subject is discussed which may include the feasible solutions of the SP in terms of size and safety when implementing inside a cockpit.

Genetic algorithm based optimal self-tuning fuzzy logic controller for power system static VAR stabiliser

In this study, a novel method is proposed for the compensation of loads that vary frequently in time. The proposed scheme is based on the fuzzy logic controller (FLC) that is widely used in control of nonlinear processes. FLC architecture is used for regulating the gains of the basis Proportional-Integral (PI) as a self-tuning controller. On the other hand, the constant gains of the basis: PI controller are optimised by a genetic algorithm. Experimental results demonstrate that the proposed method shows better performance than that of the conventional PI controller.

Disturbance attenuation of asymmetric structure by LMI based optimal state feedback controller with saturated actuators

This paper is concerned with the design of linear matrix inequalities (LMIs) based optimal state-feedback controller design for seismically excited asymmetric structures (AS) having stiffness irregularities. The system is modelled in terms of mass, natural frequencies, damping ratio and eccentricities to easily obtain torsionally flexible (TF) model. A one storey, two-way asymmetric structural system is used to illustrate the effectiveness of the approach through simulations. The modelled system has bi-lateral and rotational degrees of freedom. Frequency responses show the effectiveness of proposed controller by means of a decrease in the peak values of translation at each resonance frequency. Moreover, the time domain simulation results, acquired by using real time-history data of San Francisco and El Centro Earthquakes also show that proposed controller is very effective in reducing vibration amplitudes of each direction by applicable control signals and guaranteeing the stability of the closed loop system.