Bibhuti Bhusan Pati

Co-operative control coordination of a team of underwater vehicles with communication constraints

Co-operative control architectures for implementation of motion plan and coordination strategies for a team of Autonomous Underwater Vehicles (AUVs) using different optimization techniques are presented in this paper. The paper addresses the leader–follower formation control of multiple non-holonomic AUVs where one AUV is designated as Leader and the other participating AUVs are treated as the followers. In this scenario, the leader operates according to its optimized path, while each follower is required to follow the leader accurately maintaining desired separations and orientation with respect to the leader. A communication strategy is also designed so that the AUVs can exchange information to obtain the designated waypoints that are sent from the leader following the area coverage problem. Optimization is necessary to determine the optimal path as functions of sensor nodes for control coordination of a team of AUVs satisfying the time minimization. Various optimization algorithms have been employed for control coordination and search strategies of co-operative motion control of a group of AUVs without incorporating learning and memory to evaluate the objective function. The CLONAL selection algorithm is found to be one of the best approaches to plan the formation leader motion utilizing the triangular sensor-based grid coverage technique. The efficacy of the proposed optimization approach to solve the co-operation motion of a group of AUVs is verified through MATLAB simulation studies and the results confirmed the robustness and efficiency of the proposed technique over existing search methodologies, such as Coordinate, Multi-directional, Simplex and Simultaneous Perturbation Stochastic Approximation.

Employing nonlinear observer for formation control of AUVs under communication constraints

Purpose – The purpose of this paper is to propose development of a formation control algorithm by employing a nonlinear observer for compensating the delay in the sensor signal transmission to the controller arising due to packet dropout in acoustic medium. Design/methodology/approach – A robust control law is developed using the sliding mode approach integrated with a communication consensus algorithm for achieving cooperative motion of acoustic underwater vehicles in a group ensuring the transfer of information among the AUVs. In acoustic medium, inter-vehicle communication is challenging for a group of AUVs deployed in formation because underwater channel encounter a number of constraints such as low data rate, packet delays and dropouts. Findings – It is observed that the sliding mode control-unscented Kalman filter formation control exhibits superior control performance such as mitigating larger initial error of estimation and removing the use of the Jacobian matrices among the three controllers deve...

Comparative studies on design of fractional order proportional integral differential controller

In recent days the fractional order proportional integral differential (FOPID) controller took the place of conventional PID controller because of their proven advantages. FOPID can be used in various science and engineering applications due to comparable stability factor over PID. Research is still going on to develop tune methods for FOPID applying in existing control systems. This paper deals with the comparative studies on design of fractional order proportional integral differentia (FOPID) controller. The two well known tuning methods are described for the design of FOPID controllers parameters. The first design technique is Ziegler-Nichols tuning method for FOPID and the second technique is Astrom-Hagglund method for FOPID controller. The design techniques are described by a second order integer order plant and its robustness is checked by the simulation. In addition to that there is a comparison studies between these two methods.

Co-operative control of a team of autonomous underwater vehicles in an obstacle-rich environment

ABSTRACT This paper presents the cooperative control of a team of autonomous underwater vehicles (AUVs) in the presence of obstacles under environmental disturbance. A leader–follower formation control based on optimisation algorithms using communication topology is designed to navigate towards the target in the presence of obstacles. CLONAL selection optimisation algorithm may be employed as team controller by providing the optimal position to hierarchical control strategy for each AUV incorporating learning, memory and affinity. But unfortunately CLONAL selection optimisation algorithm fails to avoid obstacles because some of the lymphocytes become memory cells of the system. The above prematurity may be overcome by using artificial potential fields and ant colony optimisation technique combined with CLONAL selection optimisation algorithm. The efficacy of the proposed optimisation is verified through MATLAB simulation and the result confirmed the robustness and proficiency of proposed technique over CLONAL selection optimisation algorithm.

Directional relaying of series compensated line using an integrated approach

This paper presents a directional relaying algorithm based on voting technique for the protection of series compensated line where the capacitors are present at both the ends of the line. The directional relaying issues in series compensated line related to voltage inversion, current inversion, high resistance fault and load change are addressed. Four classifiers based on positive and negative sequence components are selected and integrated using the voting technique to derive the final decision. The technique is evaluated using data simulated with EMTDC/PSCAD for a series compensated line and the dynamic performance of the algorithm is also studied. The integration approach is found to be advantageous.

Design and Performance Evaluation of Fractional Order PID Controller for Heat Flow System Using Particle Swarm Optimization

The purpose of this paper is to apply a natured inspired algorithm called as Particle Swarm Optimization (PSO) for the design of fractional order proportional-integrator-derivative (FOPID) controller for a heat flow system. For the design of FOPID controller, the PSO algorithm is considered as a designing tool for obtaining the optimal values of the controller parameter. To obtain the optimal computation, different performance indices such as IAE (Integral Absolute Error), ISE (Integral Squared Error), ITAE (Integral Time Absolute Error), ITSE (Integral Time Squared Error) are considered for the optimization. All the simulations are carried out in Simulink/Matlab environment. The proposed method has shown better result in both in transient and frequency domain as compared to other published works.