Marius-Constantin Popescu

Heating monitored and optimal control of electric drives

In the first part of the paper it is considered an electric drive with static torque with constant component and speed proportional component. Using the classic calculus of variations is determined the extremal control and trajectory and the overheating that ensures maximum exploitation of the system resources represented by the achievement of a maximum variation of speed in the acceleration processes. In the second part, based on the recent discoveries in the thermovision field, we underline the importance of a system which collects, administrates, and processes thermographic images for some kinds of electric drive, where a real-time surveillance is not “must”.

The predictive control applied to an induction drive

Abstract This paper deals with the generalized predictive control applied to an induction drive with vector control and static torque, with constant and speed proportional component. First, it is defined a reduced model of the ensemble formed by the drive and the vector electronic control and then are presented the generals characteristics of the generalized predictive control that are applied to considered drive speed control. Finally, using Matlab-Simulink environment are presented and then are analyzed the performances.

Control Strategy of a 3-DOF Walking Robot

The paper presents the mathematical model of a walking robot where the active pair of legs has three free joints. The mathematical model of the robot is determined considering a systemic approach of the robot as variable causality dynamic systems (VCDS). Taking into account a possible symmetrical structure, only the vertical xz-plane evolution is considered. The results can be extended to three-dimensional space. The approach is best on variable dynamic systems, considering that each leg of the pair can change the state depending of the causality order. It is considered that the first leg has both joints free and the second leg has the second joint free. The model is implemented in MATLAB environment and some evolutions examples are presented.

Algorithm for virtual reality

POV-Ray is a freeware, stand-alone, world-class renderer that creates three-dimensional photo-realistic images taking as input a text file with the scene described in a script language known as POV-Ray Scene Description Language (SDL). Image synthesis languages like POV-Ray do not give detailed description of the surfaces of the objects they generate, and therefore it is quite difficult to use them for engineering computations. Rather than trying to solve the problem of data translation, we propose to apply the fictitious domain method in the numerical solution. We explain what the difficulties are and give some solutions with an illustration of a finite element computation for a three-dimensional acoustic scattering problem. Bishop3D is an interactive modeler and animation tool designed and built to work with POV-Ray.

Modeling the phenomenon of refreshing air inside the spaces of the fungi's culture

This paper presents an identification method of the value of concentration in certain areas of rooms for edible mushroom culture medium, in the case where the introducing of the air represents the effect of the superposition of a flow convection (natural or artificial) and diffusion and of its recirculation, which acts as a feedback circuit. The result helps to understand how to conduct a recirculation phenomenon, and may constitute a basis for future adaptive adjustment of the concentration value.