Z. Ibrahim

Modeling and System Identification using Extended Kalman Filter for a Quadrotor System

Quadrotor has emerged as a popular testbed for Unmanned Aerial Vehicle (UAV) research due to its simplicity in construction and maintenance, and its vertical take-off, landing and hovering capabilities. It is a flying rotorcraft that has four lift-generating propellers; two of the propellers rotate clockwise and the other two rotate counter-clockwise. This paper presents modeling and system identification for auto-stabilization of a quadrotor system through the implementation of Extended Kalman Filter (EKF). EKF has known to be typical estimation technique used to estimate the state vectors and parameters of nonlinear dynamical systems. In this paper, two main processes are highlighted; dynamic modeling of the quadrotor and the implementation of EKF algorithms. The aim is to obtain a more accurate dynamic modelby identify and estimate the needed parameters for thequadrotor. The obtained results demonstrate the performances of EKF based on the flight test applied to the quadrotor system.

Development of combined vector and Direct Torque Control methods for independent two induction motor drives

Many applications use two or more motors operating in parallel configuration by using one variable speed drive. This system is able to control these multiple motors at the same desired motor speed operation which provide advantages in terms of components and cost reduction. However, the system is not able to control each motor separately if it is desired to operate at different speeds and it also cannot withstand the load disturbance. To address this problem, the design of combined Vector Control-Direct Torque Control (DTC) methods is proposed and their performance is investigated for the case of independent controlled two induction motors fed by single Five Leg Inverter (FLI) method. Double Zero Sequence (DZS) Injection Method Space Vector Pulse Width Modulation (SVPWM) scheme is used for the FLI. Simulation results from the Simulink/Matlab that verify the validity of the method are also included. The results show the ability of the proposed method to control motor speed independently under forward-reverse step speed command and load disturbance condition.

Speed performance of SVPWM direct torque control for five leg inverter served dual three-phase induction motor

Independent control of multi-machine with single-converter systems is the motivation of this research study. As in the previous literature review, there is no report regarding speed control applying space vector pulse width modulation direct torque control (SVPWM-DTC) method for dual three-phase induction motor (IM) fed by a five leg inverter (FLI). Therefore, in this paper, a new and simple control method based on SVPWM-DTC for dual three-phase induction motors with only one drive of five-leg voltage source inverter is investigated. The method effectively allows independent control of two three-phase IMs. Simulations of different speed commands and variation of load condition tests have been performed. Future work is to do comparative study between vector controls (VC) versus DTC methods to the FLI performance.

Comparative study of different PWM control scheme for three-phase three -wire shunt active power filter

Instantaneous reactive power theory was the most popular control theory used when dealing with harmonics compensations. In conjunction with the instantaneous theory, switching signal generation techniques plays an important role to ensure the correct compensation signal injected in the system. Therefore, this paper discussed on comparative study of five (5) methods used in instantaneous theory namely; p-q method, modified p-q, d-q method, p-q-r method and vectorial with three (3) types of signal generation namely; carrier current control, hysteresis current control and space vector modulation control. Continuous reductions of the total harmonics distortion (THD) are expected at the supply current when applied different types of switching technique. The comparison was examining using MATLAB/Simulink (MLS) environment.

Improvement of power density spoke type Permanent Magnet Generator

This paper discusses on the improvement of power density of hollow rotor compared to conventional spoke type Permanent Magnet Generator (PMG). The objective of this research is to propose a rotor structure that could improve the power density by maximizing the flux linkage of the machine. In this research the Finite Element Analysis (FEA) is used to simulate the characteristics of the hollow rotor spoke type PMG at various speed. The result shows that the hollow-rotor topology has higher back electromagnetive force and output voltage compared to conventional spoke type PMG. In addition, the hollow-rotor spoke type motor has higher output power compared to conventional spoke type PMG. In summary, this paper provides an overview of the performance of the hollow-rotor spoke type topology that contributes high power density.

Analysis on speed characteristics of Five Leg Inverter for different carrier based PWM scheme

This paper focused on the performance analysis of two induction motor drive fed by the Five Leg Inverter (FLI). Two carrier based PWM scheme for FLI are used in these motor control analysis which are known as Double Zero Sequence (DZS) Injection Method and Two Arm Modulation (TAM). Simulink/MATLAB is used as the simulation tool for analysis. Detailed investigation of the speed response characteristics under speed command change, load disturbance, steady state stability and dynamic response is performed based on these two schemes. The results reveal that both methods have good capabilities of independently controlling the two motors. Comparison of these methods show that, DZS method has better speed and torque ripple disturbance performance at half rated speed while TAM have better performance at lower rated speed. Further analysis for the same speed demand shows that TAM has better capability for a higher same speed operation range.

Design of Auto-Stabilization Control Technique for a Quadrotor System

This paper presents the design of auto-stabilization control technique for a quadrotor system. Aquadrotor is a highly nonlinear and has to be stabilized by a suitable control technique. Therefore, the main focus of this research is to design an appropriate control algorithm that able to auto-stabilize the quadrotor at hover. The dynamic modeling of the quadrotor is described by sets of equations of motion that are derived based on the Newton-Euler formalism with the implementation of UKF for parameter identification and state estimation. The control strategy adopted includes feedback linearization coupled with Proportional-Derivative (PD) controller for the translational subsystem and backstepping based Proportional-Integral-Derivative (PID) controller for the rotational subsystem. It is developed in MATLAB/Simulink platform and is validated via real-time implementation. Both controllers give satisfactory simulation results, where acceptable peak of overshoot and small steady state errors are achieved. Experimentally, the throttle is controlled in manual mode while attitude angles are stabilized automatically. The simulation and experimental results show that the proposed controller is able to effectively stabillized the quadrotor.