Application of the frequency response methods to the controller design of multivariable induction motor.

Ph.D. - Doctoral Progra

OBJECT-ORIENTED REPRESENTATION OF A ROBOT MANIPULATOR

The paper presents an object-oriented representation of a robot manipulator. The representation developed here is appropriate to implement a robot simulation package. The software package is easy to use and gives insight to the robot kinematics, the dynamics and the control subjects. The robot representation has been tested in resolved motion rate control and hybrid position/force control applications

Design of a variable five-axes adjustable configuration robot manipulator

A robot manipulator design is presented in this paper supplying a few kinematical configurations in a single structure which is in the mean time, reconfigurable for given tasks and hence making the level of flexibility and adaptability much higher for changing working environment

System design and control framework for an autonomous mobile robot application on predefined ferromagnetic surfaces

Maintenance tasks of ferromagnetic. surfaces present a suitable field for robotic applications. A system and controller software design satisfying the system requirements of an autonomous robotic system moving on a ferromagnetic surface accomplishing several tasks such as crack detection, welding, painting and emergency recovery actions is presented. The controller software developed here is a hierarchical control system based on the RCS Reference Model Architecture. The software shell and selected developed modules of the controller are presented

Compensation of nonlinear effects in three-level neutral-point-clamped inverters based on field oriented control

In this paper, the nonlinear effects in three-level neutral-point-clamped inverters will be studied and a compensation algorithm, based on field oriented control (FOC) technique, will be proposed. In voltage source inverters (VSIs), nonlinear effects such as voltage drops on power semiconductors, and their turn on/turn off times cause distortions at the output voltage. Also dead-time, inserted in order to avoid short-circuits, are another source of nonlinearity. The proposed compensation algorithm is developed by analyzing the effects of nonlinearities in each switching period and correcting modulation signals with compensation signals accordingly. The algorithm is implemented in software and does not require any additional hardware. The proposed algorithm is verified by simulation results and experiments

OBJECT RECOGNITION AND LOCALIZATION WITH ULTRASONIC-SCANNING

In this paper an object recognition and localization system based on ultrasonic range imaging to be used in optically opaque environments is introduced. The system is especially designed for robotics applications. The ultrasonic image is acquired by scanning ultrasonic transducers in two dimensions above the area where objects are located. The features that are used for recognition and localization processes are extracted from the outermost boundaries of the objects present in the input scene. Experimental results concerning the applications are presented

Compensation of Dead-time Effects in Three-level Neutral Point Clamped Inverters based on Space Vector PWM

hi this study the effects of dead-time in three-level neutral-point-clamped (NYC) inverter is analyzed and a compensation algorithm based on space vector pulse width modulation (PWJI) is proposed. In three phase inverter applications, different modulation techniques are utilized depending on the application. Among these, space vector pulse width modulation (SVPWM) technique is the modulation technique with which best bus bar utilization is achieved. This modulation technique is also applicable to three-level NPC inverters. The most common space-vector modulation technique for three-level NPC inverters is the Nearest Triangle Vector (NTV) SVPWM technique. This paper focuses on the effects of dead-time in three-level neutral point clamped inverters based on NTV SVPWM. The proposed algorithm is implemented on software and does not require an additional hardware. The analysis and compensation algorithm are verified by computer simulation

CALCULATION OF THE OVERLAP ANGLE IN SLIP ENERGY RECOVERY DRIVES USING A D,Q/ABC MODEL

In this paper, a closed-form expression to estimate the overlap angle in a slip energy recovery system is presented. The prediction of the overlap angle is important in the case of doubly-fed induction motor drives, because of its influence on speed and torque. A closed-form expression is derived using a hybrid model of the induction motor and a dynamic model of the rotor rectifier. The ripple content of the dc link current and the inverter input voltage are neglected. The predicted results obtained using the closed form expression are verified experimentally

Harmonic Minimization in a Three-phase Asymmetrical PWM Rectifier

- A new pulse-width modulation (PWM) method for a three-phase bridge rectifier developed here gives minimized low order harmonics. As a PWM rectifier, it offers better input and output characteristics than phase-controlled rectifiers. It has inherited the chmcteristics of the PWM rectifier such as having high power factor at the input with low harmonic content of the input current and zero phase-shift of input voltage and current. The availability of power transistors at high power ratings enabled the implementation of PWM rectifiers much easily. The modulation method is applied to a dc-motor drive system at 1kW rating. A high speed micro-controller produces the switching pulses

STARTING TRANSIENTS IN SLIP ENERGY RECOVERY INDUCTION-MOTOR DRIVES .1. FORMULATION AND MODELING

A detailed study of the rotor phenomena including the rectifier commutation angle and inverter harmonics is facilitated by the use of the actual rotor conduction sequence variables instead of transformed variables that are used in most other IM drive systems. The starting transients of slip energy recovery IM drives comprising three stages are presented here; (a) the starting from zero speed with a starting resistor connected to the output of the rotor rectifier; (b) a transition period in which the inverter is connected through a dc link; (c) the final period when the starting resistor is disconnected from the rectifier output. This paper uses a hybrid model which retains the actual rotor phase variables but transforms those of the stator only, to examine the starting transients of a slip energy recovery drive system. The model has the advantage of not having a variable inductance matrix. Hence the computation time is substantially reduced