Radu Balan

Genetic algorithms to optimal design of a 3 DOF parallel robot

The paper presents a multi-objective optimum design procedure to a 3 degrees of freedom (DOF) parallel robot with regards to four optimality criteria: workspace boundary, transmission quality index, stiffness and numerical aspects. Additional objective functions can be used to extend the proposed design procedure to more general but specific design problems. The main aspects of their structure, kinematics, workspace, parameter design and optimization indices are introduced. A kinematic optimization was performed to maximize the workspace of the parallel robot. In order to perform an optimal design of 3 DOF parallel robots, an objective function was developed first, and then genetic algorithms applied for optimization. The experimental results demonstrate the advantages of the presented optimal design method in design of a 3 DOF parallel robot. The performances of the 3 DOF translation parallel robot provide high potential and good prospect for their practical implementation in manufacturing industry.

Supervisory and Control System for Thermal Treating Processes

Nowadays, there are a lot of achievements in the field of thermal treating processes, in industrial automation on the market. The paper focuses on giving an alternative approach for the furnace control, in order to contribute to global performance improvement of the heat treatments (providing high quality products, reducing the energy consumption, and the wastes). The paper describes our effort focused on improving implementation techniques for the development of a surveillance system for thermal treating processes, in order to enhance the performance of the entire system. Two approaches (both under development), are discussed: one version of the surveillance system, which supports interpreted languages (Tcl/Tk, Python, Ruby, BLT, TkZinc), and the other one which is based on compiled languages (OOP, Lazarus). These two alternatives are compared from the perspective of a certain operating system: Windows, or Unix. The authors evaluated also the capabilities of using external packages (for networking, graphics, data storing). Finally several guidelines for developing the surveillance system for the class of thermal treatment processes are proposed, and the networking components of the surveillance system are considered from the perspective of a distributed plant (both LAN Ethernet, and wireless solutions)

Optimization of a six degree of freedom micro parallel robot

In this paper a mono-objective optimum design procedure for a six-degree of freedom parallel micro robot is outlined by using optimality criterion of workspace and numerical aspects. A mono-objective optimization problem is formulated by referring to a basic performance of parallel robots. Additional objective functions can be used to extend the proposed design procedure to more general but specific design problems. A kinematic optimization was performed to maximize the workspace of the mini parallel robot. Optimization was performed using genetic algorithms.

Implementation of a load control method for the improvement of the efficiency of a fuel cell, based on the hardware-in-the-loop technique

The development of low resistance membranes, highly diffusive electrodes, and reduced use of noble metal catalysts are the recent breakthroughs that brought the fuel cell to the fore-front. However, some parameters like hydrogen and oxygen flow, temperature, water flow and load must be controlled, in order to obtain the maximum efficiency out of a fuel cell. This paper is focused on variable load control using the hardware in the loop (HIL) technique. A three-stage SMPS converter is proposed and analyzed. An experimental setup was made using a model vehicle powered by a fuel cell. In order to simulate a real-life hilly track of an electric fuel cell powered vehicle, an HPS Motor Board and dSpace HIL were used.

A Multicriteria Approach for the Optimal Design of 2 DOF Parallel Robots Used in Construction Application

Parallel robots have been used in a large number of applications ranging from astronomy to flight simulators and are becoming increasingly popular in the field of construction industry. This paper is aimed at presenting a study on the optimization of the BIGLIDE and BIPOD parallel robots, which comprises two-degree-of-freedom (DOF) parallel robots with constant and variable struts. The robot workspace is characterized and the inverse kinematics equation is obtained. In the paper, design optimization is implemented with Genetic Algorithms (GA) for optimization considering transmission quality index, design space and workspace. Here, intended to show the advantages of using the GA, we applied it to a multicriteria optimization problem of 2 DOF parallel robots. Genetic algorithms (GA) are so far generally the best and most robust kind of evolutionary algorithms. A GA has a number of advantages. It can quickly scan a vast solution set. Bad proposals do not affect the end solution negatively as they are simply discarded. The obtained results have shown that the use of GA in such kind of optimization problem enhances the quality of the optimization outcome, providing a better and more realistic support for the decision maker. Considering its high load capacity and geometrical dexterity, the system is appropriate for maintenance, building construction, and cleaning of large and dangerous structures.

Stability of the Fast Voltage Control Loop in DC-DC Converters

This paper describes a method for stability analysis and design of a fast voltage loop in DC-DC converters. The method is based on the Popov criterion, which unifies tools for nonlinear system analysis with frequency domain analysis tools used in linear systems. This study establishes sufficient conditions for absolute stability of time-varying control systems. The proposed conditions extend in a simple way the classical Popov criterion to time-varying memoryless nonlinearities, using previous results of Kharitonov. They are expressed in terms of linear matrix inequalities (LMIs). The controller design procedure is demonstrated and experimentally verified on a DC-DC converter