The paper presents the idea of a system for controlling the movement of a flowmeter for air velocity profile measurement. In such a system, due to massive amount of data and limitations of the Data Acquisition Equipment, it is necessary to use moveable sensors. The flowmeter sensor is moved with the use of a linear module with a stepper motor and a tooth-belt drive. The location and speed of the sensor are controlled by a program based on the idea of virtual instrument. The proposed structure allows the user to control operation of the stand and provides automatic measurement. A wide range of velocity and step increments of the stepper motor drive, and flexibility of the virtual instrument software, allow one to create effective measurement systems ensuring sufficiently precise location with optimal time duration of measurement. It is shown that the linear module with tooth-belt is an effective alternative for similar modules with micro-screw drives.

The aim of the paper is to present a procedure for generating service loading for fatigue tests of materials and structures. The generated loading characterizes desired functions of probability distribution and autocorrelation. The proposed numerical procedure uses MATLAB toolboxes and consists of three steps: (a) generation of a sequence of real numbers with the desired autocorrelation function and with any probability distribution function; (b) generation of loading history with the desired probability distribution function; (c) rearrangement of loading history (mentioned in item b) based on a sequence of real numbers with the desired correlation (mentioned in item a).