Prasanta Roy

This paper aims to show better performance of Fractional Order Integral State Feedback (FOISF) controller over Integral State Feedback (ISF) controller with experimental validation in level control of a two tank (non interactive) system. A nonlinear as well as a linear model of the system is obtained using physical laws and experimental open loop response. Considering the linear model an ISF controller has been designed using pole placement technique. FOISF controller is designed considering the nonlinear model using Particle Swarm Optimization (PSO). Proposed controllers are validated in an experimental set up manufactured by Feedback Instruments (Model No 33-041S). Experimental results reveal that FOISF controller provides better performances than that of ISF controller.

In this paper, the author has proposed a Fractional Order Proportional Derivative (FOPD) controller tuned by Firefly Algorithm, that has a high convergence rate, robustness and the capability to attain global optimum in less number of iterations. The facts and contributions distinguishing this work are: Firstly, the simulation has been carried out without linearizing the Ball and Plate system, thus maintaining the physical nonlinearity intact in the system. Secondly, the IOPD (Integer Order Proportional Derivative) controller designed has been tuned by Firefly Algorithm, and provides improved results compared to the existing controller inbuilt in the system. Thirdly, the model (33-240, Feedback Instruments) taken for simulation is a newer version of Ball and Plate System, with not much research work done on it till date. Hence, comparisons of the results obtained have been done with that of an older model (CE151, Humusoft).The comparison has also been carried out with the PD control...

Often in a coupled two tank MIMO system, the level of the first tank is required to be kept at a constant level while the level of the second tank is required to follow a time varying reference signal. Sometimes controllers of the PID family along with conventional feedforward controllers may not be able to maintain the constant level in the first tank rejecting the disturbance due to the change in the level of the second tank without deteriorating the tracking performance of the level of the second tank. This paper shows analytically as well as experimentally that Fractional Order Proportional Integral (FOPI) controllers along with conventional feedforward controllers work better than PI/PID/2DOF-PI/3DOF-PI with feedforward controllers in such situation. FOPI controller is designed using the frequency domain approach. Effectiveness of the controllers is tested to maintain a constant level in the first tank while making the level of the second tank to follow a sinusoidal and square wave reference signals. Experimental results validate the objective of the paper.

This paper deals with real-time identification of magnetic levitation model. For this motive, two methodologies are adopted namely, integer order identification and a new concept of fractional order system identification that has been incorporated for the first time in this particular model. A comparison of the two is shown in which the latter fares better. It is worth mentioning that all identifications have been performed on real time, unlike most identifications which are done only on simulation basis. The main contribution of this work has been basically the applying of fractional calculus in system identification, a concept less explored but with remarkable results.

This paper proposes design of proportional and derivative (PD) controllers in cascade control scheme to control trajectory of a ball in a ball and plate system. Ball and plate system, manufactured by Feedback instruments (Model No. 33-240), is realized in MATLAB–Simulink environment as a platform to test the performance of proposed controllers. Neglecting cross-coupling between motions along x- and y-axes, a decoupled nonlinear model of the system is realized in MATLAB–Simulink environment. A cascaded control strategy is adopted to make the ball follow a reference trajectory specified by user. PD controllers are used in both inner and outer loop of cascade control strategy. Parameters of PD controllers are tuned by particle swarm optimization (PSO) which does not require in-depth analysis of the nonlinear plant dynamics. Effectiveness of proposed controllers is tested by checking the ability of the ball to track reference trajectories like circle, spiral, square, and hexagon.

This paper puts forward the design of PID and FOPID controllers along with its validation through hardware implementation in the Maglev system. The purpose of this work is not only to stabilize a ferromagnetic ball but also to control its position to track a reference signal. The designs have been carried out using the optimizing algorithms namely, the Gravitational Search Algorithm (GSA), Particle Swarm Optimization (PSO) and a hybrid of both the algorithms i.e. PSOGSA. The experimental set up is manufactured by Feedback Instruments (Model No 33-210). The experimental results obtained using a wide variety of test signals prove that the hybrid algorithm PSOGSA is better than its individual counterparts with satisfactory transient and steady state responses and also the performance of FOPID is an improved one compared to that of PID.

This paper concerns design and implementation of PID and fractional-order PID (FOPID) controllers to control position of an electromagnetically suspended ferromagnetic ball in a magnetic levitation (Maglev) system in real time. The Maglev system, manufactured by Feedback Instruments (Model No 33-210) is used as a platform to test the performance of proposed controllers. Parameters of PID and FOPID controllers are tuned by firefly algorithm (FA). FA is a metaheuristic algorithm based on movement of fireflies toward more attractive and brighter ones. PID and FOPID controllers are implemented in MATLAB and SIMULINK environment inside PC using fractional-order modeling and control toolbox. Controller in the SIMULINK environment inside PC is connected to the Maglev system through Advantech card. Effectiveness of proposed controllers is tested by checking the ability of the suspended ball to track a reference signal. Step change, sine wave, and square wave are used as reference signals. Real-time results have revealed satisfactory transient and steady-state responses over the contemporary existing controllers. FOPID controller showed better results compared to PID.