Search results for "Control theory"

Multi-rate PID Controller for a Networked Control System

2007

In networked control systems several devices (controller, process and others) share a common communication bus. This feature can suppose delays when those devices try to transmit information through the unique bus, leading to a non- regular behaviour, that is, different variables are sampled and updated in a non-uniform way along the time. As a result, if the control system is designed by means of classical design techniques, control performance can be degraded, since these techniques used not to consider those delays. In order to undertake this problem, a solution based on a PID controller's parameters readjustment is proposed. This approach permits to retune these parameters depending on …

A Method for Reduction of Cogging Torque in PM Machines Using Stepped Magnets

2006

The paper presents a general approach to minimization of the cogging torque in electrical machines using surface-mounted magnets with discrete skew angle. Two types of pole shapes, namely monotonic skewing as well as herringbone-shaped magnets are proposed for the purpose of reducing the cogging torque. The elaborated algorithm is validated against the 3D finite element model as well as experimental data obtained from physical model of the motor. The presented cost-effective method leads to a great reduction of cogging torque with only slight decrease of overall electromagnetic torque.

5-axes modular CNC machining center

2017

The paper presents the development of a 5-axes CNC machining center. The main goal of the machine was to provide the students a practical layout for training in advanced CAM techniques. The mechanical structure of the machine was built in a modular way by a specialized company, which also implemented the CNC controller. The authors of this paper developed the geometric and kinematic model of the CNC machining center and the post-processor, in order to use the machine in a CAM environment.

A Simple Multibody Dynamic Model of Cross-Country Ski-Skating

2013

The purpose of this paper is to present the development of a simple multibody dynamic model matching the observed movements of the center of mass of a skier performing the skating technique in cross-country skiing. The formulation of the equation of motion was made using the Euler–Lagrange equations applied to a multibody tree-type system in three dimensions. The description of the lower limb of the skier and the ski was completed by employing three bodies, one representing the ski, and two representing the natural movements of the leg of the skier. This simple model is able to show an approximation of the movement of the center of mass of the skier and its velocity behavior allowing to stu…

Speed and rotor flux estimation of induction motors via on-line adjusted extended kalman filter

2006

This paper deals with the estimation of speed and rotor flux of induction motors via Extended Kalman Filter (EKF) with on-line adjusting of the system noise covariance matrix. The predictor of EKF consists of a discrete time model obtained by means of a second order discretization of the original nonlinear model of the induction motor. In order to obtain accurate estimation of the above mentioned variables, the load torque is included in the state variables and then estimated. Three different system noise models are also illustrated and compared each other by simulations carried out in Matlab/Simulink environment. For one of these models, EKF is adjusted on-line by means of an additional PI…

Model predictive control for drum water level of boiler systems

2014

Allocation of actuators and sensors for coupled-adjacent-building vibration attenuation

2013

An actuator and sensor allocation approach is proposed for the design of coupled-adjacent-building vibration suppression under seismic excitation. This paper first establishes a full-order model of adjacent buildings with the location information of actuators and sensors. Then, the order of the model is reduced via modal cost analysis, by retaining the modes contributing the most. In view of the fact that the output powers of the actuators are limited, this paper brings forward a mixed H∞/GH2 control. By considering that not all the states of the system can be measured by the sensors, a dynamic output feedback controller is designed. The genetic algorithm is employed to obtain the locations…

Speed Control of a two-Degrees of Freedom Induction Motor with Rotor Helical Motion for Industrial Applications

2014

This paper describes the realization of a two-degrees of freedom induction motor prototype with rotor helical motion, suitable for several industrial applications as grinders, augers, drilling and milling spindles, robotic arms and drives for medical tools and prostheses. This prototype was realized by combining a three-phase tubular linear induction motor (TLIM) with the stator of a three-phase rotary induction motor, resulting in a THMIM (Tubular Helical Motion Induction Motor). Moreover, a possible simple electrical drive, capable to control the helical motion, is proposed, simulated and analyzed. In particular, the mathematical model of the THMIM has been initially developed and, then, …

Sensorless low Range Speed Estimation and Parameter Identification of Induction Motor Drives Devoted to Lifts Automatic Rescue Devices

2010

In this paper a sensorless rotor speed estimation and parameter identification algorithm is presented. The algorithm is designed specifically for induction motor (IM) drives devoted to automatic rescue devices (ARD) used in lifts and hoist applications. Its peculiarity is that it is based on the sinusoidal steady state mathematical model of the IM and, therefore, can be implemented on a low cost micro-controller in a simple way, however without lacking in terms of dynamic performance. It is also capable of self tuning so that no information is required about the specific IM used in the ARD drive. Finally the algorithm allows also an appreciable energy saving of the ARD when compared to olde…

Experimental investigation on high efficiency real-time control algorithms for IPMSMs

2014

This paper describes an experimental investigation on the power losses variations occurring in an Interior Permanent Magnet Synchronous Motor (IPMSM) with respect to the direct axis current component. Such investigation can be useful to determine a mathematical model accounting for copper, iron and mechanical friction losses, and for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. In particular, a test bench has been set up in order to carry out all measurements and the final power loss identification. The test bed is composed by a IPMSM drive with a field oriented control (FOC) strategy, a power analyzer, a dynamometric brake a…