The paper presents a basic description and examples of the use of so called descriptive functions, allowing analysing the influence of inherent and indispensable components of all mechatronic systems mechanical subsystems - so called hard nonlinearities. These parts “causing” - in addition to the centrifugal and Coriolis generalized forces- the nonlinearity of the system, can be analysed by the abovementioned method from the point of view of their origin and the estimation of the basic parameters of their frequent consequences - so-called limit cycles. After a short introduction, which introduces and explains describing functions using the example of a nonlinear system taken from the literature, some of the socalled hard nonlinear subsystems (such as the mechanical chain of robots) are shown to be used. The paper is the first part of a more extensive description analysis of nonlinear systems concept using these functions in order to enable analysis and prediction of limit cycles.

Variations of un-maned vehicles or drones are widely used in diverse fields, including monitoring or manipulation with dangerous substances. One of the best drone construction, which can be used in these fields is an X-copter. This paper serves as an introduction to basics of quadcopter anatomy and advice to choose components based on their properties. In addition, it shown variants of connection between microcontroller and motors for test purpose and an example of programming. This information can be used in education process or for those who want to use a microcontroller Raspberry in their work.

Abstract. The expanding capabilities of today's microcontrollers and other devices lead to an increased utilization of these technologies in diverse fields. The automation and issue of remote control of moving objects belong to these fields. In this project, a microcontroller Raspberry Pi 2B was chosen for controlling DC motors and servo-motors. This paper provides basic insight into issue of controlling DC motors and servo-motors, connection between Raspberry and other components on breadboard and programming syntaxes for controlling motors in Python programming language.

Abstract. Text deals with 6 degree of freedom measuring robot kinematics description enabling manipulation with measuring effector in 3D space. Mentioned description flowing from Denavit-Hartenberg notation for serial ordering of ideally stiff bodies connected by kinematic pairs, makes possible to create complete set of transformation matrices for coordinates transformation from distal to the adjoining proximal Cartesian coordinate system, which enables to calculate the coordinates of arbitrary structure point by means of joints' coordinates. Thenceforth it makes possible to determine standby and available robot workplace and mainly to perform the analysis of one fundamental control system problem of such robots-i. e. solving inverse kinematic problem.

When designing a mechatronic system, several steps are taken into account. One of the main steps is the design of a CAD model representing the physical part of the system, and another major point is the development of the mathematical model necessary for the respective controller design. This paper combines both design steps and shows the advantages of using this approach. First, a CAD model is created considering the kinematic and dynamic behavior of the system as well as respective material properties. This CAD model is, in parallel, used for both purposes: as the main basis for developing a mathematical model that will be used for definition of control laws and appropriate system controllers, and also to generate a physical model as result of exporting to MATLAB/Simulink (Simscape/SimMechanics library) in order to simulate the system behavior. This translation does not consider only the standard CAD model export to the SimMechanics library when forces and torques between links are clearly defined, but also the correct way to add corresponding limiting forces/torques. When comparing the behavior of the physical model and the mathematical model, it is important to obtain similar results, especially when it is necessary to perform some simplifications of a mathematical model, as happens in the context of nonlinear systems control. All these issues are discussed in this paper and the obtained simulation results for both models are similar, which confirms the proposed approach.