A.P. Mittal

Performance analysis of two-degree of freedom fractional order PID controllers for robotic manipulator with payload

The robotic manipulators are multi-input multi-output (MIMO), coupled and highly nonlinear systems. The presence of external disturbances and time-varying parameters adversely affects the performance of these systems. Therefore, the controller designed for these systems should effectively deal with such complexities, and it is an intriguing task for control engineers. This paper presents two-degree of freedom fractional order proportional-integral-derivative (2-DOF FOPID) controller scheme for a two-link planar rigid robotic manipulator with payload for trajectory tracking task. The tuning of all controller parameters is done using cuckoo search algorithm (CSA). The performance of proposed 2-DOF FOPID controllers is compared with those of their integer order designs, i.e., 2-DOF PID controllers, and with the traditional PID controllers. In order to show effectiveness of proposed scheme, the robustness testing is carried out for model uncertainties, payload variations with time, external disturbance and random noise. Numerical simulation results indicate that the 2-DOF FOPID controllers are superior to their integer order counterparts and the traditional PID controllers.

Power Quality Enhancement with DSTATCOM for Small Isolated Alternator feeding Distribution System

This paper focuses on power quality improvement with DSTATCOM on a small, isolated 42.5 kVA alternator feeding a three-phase, three-wire distribution system. Some power quality aspects like power-factor correction, voltage regulation and load balancing of linear load are discussed and implemented using DSTATCOM. DSTATCOM is realized using a three leg IGBT based PWM-VSI bridge having a DC bus capacitor. A hysteresis rule based carrier-less PWM current controller is used to derive gating pulses for the IGBT switches. The models are developed and simulated in MATLAB using Simulink and Power System Blockset (PSB) toolboxes. It is observed that DSTATCOM is effective in compensating reactive power and improving the power quality of the distribution system

ANN based self tuned PID like adaptive controller design for high performance PMSM position control

Proportional-integral-derivative (PID) being the most simple and the widely deployed controller in the industrial drives is not quite amenable to the solution for high performance drives as these drives are subjected to the parametric uncertainty, unmodeled dynamics and variable load conditions during operation. In order to expand the robustness and adaptive capabilities of conventional PID controller, a neural network based PID (NNPID) like controller which is tuned when the controller is operating in an on line mode for high performance permanent magnet synchronous motor (PMSM) position control is proposed in this paper. The NN based PID like controller is composed of a mixed locally recurrent neural network and contains at most three hidden nodes which form a PID like structure. A novel training algorithm for the PID controller gain initialization based upon the minimum norm least square solution is proposed. An on line sequential training algorithm based on recursive least square is then derived to update controller gains in an on line manner. The proposed controller is not only easy to implement but also requires least number of parameters to be tuned prior to the implementation. The performance of the proposed controller is evaluated in the presence of parametric uncertainties and load disturbances also the result outcomes are compared with the conventional PID controller, optimized using Cuckoo search based optimization method.

Modeling, Design and Analysis of Different Controllers for DSTATCOM

This paper deals with different control strategies for DSTATCOM (distribution static compensator) for power quality improvement for a three-phase, three-wire distribution system. A three-leg voltage source inverter (VSI) configuration with a dc bus capacitor is employed as DSTATCOM. The hysteresis as well as PWM current controllers are designed, analyzed and compared for PI controller and sliding mode controller. The capability of the DSTATCOM is demonstrated through results obtained using MATLAB and Simulink based developed model of the DSTATCOM system. The performance of the DSTATCOM acting as a shunt compensator is found satisfactory under varied load perturbations.

Optimal Speed Control of Hybrid Electric Vehicles

The main objective of this paper is to control the speed of Nonlinear Hybrid Electric Vehicle (HEV) by controlling the throttle position. Various control techniques such as well known Proportional-Integral-Derivative (PID) controller in conjunction with state feedback controller (SFC) such as Pole Placement Technique (PPT), Observer Based Controller (OBC) and Linear Quadratic Regulator (LQR) Controller are designed. Some Intelligent control techniques e.g. fuzzy logic PD, Fuzzy logic PI along with Adaptive Controller such as Self Organizing Controller (SOC) is also designed. The design objective in this research paper is to provide smooth throttle movement, zero steady-state speed error, and to maintain a Selected Vehicle (SV) speed. A comparative study is carried out in order to identify the superiority of optimal control technique so as to get improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs.

Direct torque control: a practical approach to electric vehicle

Electric vehicle (EV) propulsion system using induction motor drive employing direct torque control (DTC) is becoming popular because of quick response and simple configuration. This method consists of the control of the torque and the stator flux directly, based on their instantaneous errors. It allows a precise and a quick control of the induction motor flux and torque. This strategy is extensively used in electric vehicle application. In this paper, the behavior of DTC based induction motor for an EV is studied through simulation using MATLAB. The starting, acceleration, deceleration and braking features of the EV drive are simulated and presented in detail

Comparative analysis of various control techniques for inverted pendulum

In this paper conventional proportional-integral-derivative (PID) controller and different type of fuzzy logic controllers are used for controlling the inverted pendulum. The fuzzy logic controller is designed in various forms in the Matlab-Simulink environment with Mamdani type fuzzy inference system. The Inverted Pendulum system (also called “cart-pole system”) is a classic example of a nonlinear and unstable control system. By controlling the force applied to the cart in the horizontal direction, the inverted pendulum can be kept in various unstable equilibrium positions. Fuzzy control in association with PID control is found better amongst the fuzzy PD and fuzzy PD+I control.

Application of Battery Energy Operated System to Isolated Power Distribution Systems

This paper deals with model of battery energy operated system for a 42.5kVA DG set using Simulink and Power System Block-set in MATLAB environment. Battery Energy Storage System (BESS) is employed for compensation along with a small synchronous generator of 42.5kVA capacity coupled to a diesel engine as a prime mover. The DG set feeds a wide variety of loads. The performance of the system is simulated for linear, non-linear balanced and unbalanced loads. Simulation results justify enhanced power quality of the system with BESS application.

Identification of optimal wavelet-based algorithm for removal of power line interferences in ECG signals

Identification of optimal denoising algorithm for ECG signals using DWT is described. The parameters are determined by comparing different types of wavelet functions, decomposition levels and threshold selection methods. The algorithm is used to improve the SNR of the ECG contaminated by disturbances like power line interferences, to present a clean signal for accurate auto diagnosis.

Application of DSTATCOM for Mitigation of Voltage Sag for Motor Loads in Isolated Distribution Systems

This paper deals with one of the potential applications of distribution static compensator (DSTATCOM) to industrial systems for mitigation of voltage dip problem. The dip in voltage is generally encountered during the starting of an induction motor. Isolated distribution systems are comparatively not as stiff as grid systems; so large starting currents and objectionable voltage drop during starting of an induction motor could be critical for the entire system. DSTATCOM is one effective solution for isolated power systems facing such power quality problems. The model of DSTATCOM connected in shunt configuration to such an isolated system (3phase, 42.5 kVA alternator) feeding dynamic motor loads is developed using Simulink and PSB of MATLAB software. Simulated results demonstrate that DSTATCOM can be a considered as a viable solution for solving such voltage dip problems