Pavel Houška

The enhancement of PCSM method by motion history analysis

This paper deals with the identification of wheel robot position and orientation when dealing with the global localization problem. We used a method called PCSM (Pre-Computed Scan Matching) for solving this problem for autonomous robot in known environment. This method was developed for small robots. The identification of the position and orientation of the robot is based on the fusion of pre-computed match data and the analysis of the history of robot motion. The paper provides information about this fast yet simple method.

Rapid matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging with scanning desorption laser beam.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) imaging of surfaces and tissues is a rapidly evolving technique having great potential in the field of biosciences. In earlier times, acquisition of a single high-resolution MS image could take days. Despite the recent introduction of high-repetition rate lasers to increase sample throughput of axial TOF MS instruments, obtaining a high-resolution image still requires a few hours. This paper shows that a substantial increase in the throughput of the TOF MS-based tissue imaging can be achieved by incorporating a mirror providing high-speed precision scanning of the laser beam along the sample surface. Equipped with the scanning mirror, a laboratory-built axial MALDI TOF MS instrument utilizing a 4-kHz UV laser recorded a 100 × 100 pixel MS image in ~11 min using 100 laser shots per pixel. This is almost an order of magnitude faster when compared to a modern commercial instrument equipped with 1-kHz laser.

Control Method for Elimination of Self–Excited Oscillations during Turning

The oscillations occurring between the tool and the machined area during the turning process lead to degradation of the machined surface, cause poor geometric accuracy, accelerate tool wear and generate noise. This paper deals with the possibility of elimination of these self-excited oscillations by changing the parameters of the turning process. On the basis of the regenerative principle of self-excited oscillation generation, a computer model of the machining process was developed. Furthermore, a PID controller was proposed to control the compensation of the vibrations and its suitability for elimination of the self-excited oscillations was verified experimentally.

EVALUATION OF SURFACE QUALITY OF X210CR12 STEEL FOR FORMING TOOLS MACHINED BY WEDM

e-mail: mouralova@fme.vutbr.cz The stressed parts of forming tools are usually made of tool alloy steel X210Cr12 with additional thermal treatment. When machining these parts, due to the high demands on shape and precision, wire electrical discharge machining (WEDM) is used, which a method is belonging to the group of non-convention machining technologies. WEDM uses physical principles to cut material, which enables for machining parts which were already thermally treated. The long-term trend of improving precision and quality of the machined surface leads to the necessity of its thorough studying. This study concerns itself with evaluating the morphology of the worked surface using electron microscopy (SEM) and chemical composition analysis (EDX). The focus was to evaluate the quantity of the adhered material from the brass wire electrode. Furthermore, surface and profile parameters of the machined surface were studied using Atomic force microscope (AFM). Samples for the experiment were made of X210Cr12 steel, which was treated with 4 different thermal treatments.

EXPERIMENTAL EVALUATION OF WEDM MACHINED SURFACE WAVINESS

Wire Electrical Discharge Machining (WEDM) an unconventional machining technology which has become indispensable in many industries. The typical morphology of a surface machined using the electrical discharge technology is characterized with a large number of craters caused by electro-spark discharges produced during the machining process. The study deals with an evaluation of the machine parameter setting on the profile parameters of surface waviness on samples made of two metal materials Al 99.5 and Ti-6Al-4V. Attention was also paid to an evaluation of the surface morphology using 3D colour filtered and non-filtered images.

Device for Measuring of Active Power and Energy at Machine Tools

This article describes developing of device for measuring active power and energy at machine tools. Demands on measuring of electric energy flow in machine tools are more often with requirement to increasing of efficiency. This problematic is very complicated, because there are some types of electric power supply. Machine tools have main supply with harmonic supply with disturbance, direct current supply with high-frequency disturbance and power supply with PWM modulation. This device primary serves for measuring of AC power between inverter and motor, but also is able measure at other places. Developing consist from developing of electronics and algorithm. Both these part are describes in article.

Design of Sensor System for the Linear Actuator of Stewart Platform

The article deals with description of design of sensor system for linear actuators. These constitute a part of a parallel kinematic machine based on a structure of a Stewart platform. The machine is intended for testing of bone implants in biomechanical and medical practice. The developed Stewart platform presents a mechatronic system. Hence the design of mechatronic systems known as a V-model was used. The system of sensors has been developed since the middle phase of the Stewart platform development.

Design of the Controller for Elimination of Self-excited Oscillations

The article deals with design of the controller for elimination of self-excited oscillations during machining. These oscillations are generated between a cutting tool and a work-piece surface and lead to decreased quality of the machined surface as well as decreased geometrical precision. The secondary effect is increased level of noise emissions. In general, the self-excited oscillations negatively affect the working productivity of metal cutting machines and inhibit its growth. The design of the controller is based on a model of the cutting process which works with so-called regenerative principle of the self-excited oscillations generation and is based on the variable chip thickness. The model itself serves to derivation of the controller gains. A piezoelectric compensator of the cutting force is controlled by the designed PSD controller. The compensator changes the position of the tool against the machined surface thereby changing the chip thickness.

Control units for small electric drives with universal software interface

This contribution deals with a design of software interface for control units of different types of electric drives. Major part of control units software can be uniform, only the power circuit differs, as the analysis of existing solutions has shown. Thus it is possible to design universal software interface, in terms of this analysis, consisting of interconnected cooperating modules. This paper describes objectives and implementation of such modules, and also provides description of proposed universal interface architecture. The method of employment is shown on a case of control units for drives with DC and stepper motors.

Design of Mass Spectrometer Control in NI LabVIEW and SolidWorks

This paper deals with designing and testing new software functions for control of a mass spectrometer, which is type of TOF-MALDI and for depositing interface. The functions are tested on virtual motion analyses of 3D CAD model. Then they are implemented in final application for real system. Applications and functions are developed in graphical development system National Instruments LabVIEW and 3D models of devices are made in SolidWorks.