Michal Kelemen

VFH*TDT (VFH* with Time Dependent Tree)

A new modifications of VFH+ and VFH* (Vector Field Histogram) methods are presented in the paper. The features of the histogramic algorithms are generally improved and also using a potential of advanced sensors such as laser scanners is enabled. The main focus of the work is an introduction of modifications that provides collision-free navigation in environments with moving obstacles. For this purpose, a new approach in creating a look-ahead tree is proposed. All new modifications are analyzed and experimentally verified. The results obtained using conventional and modified methods have been compared. Experiments have demonstrated the validity and the technical feasibility of the proposed methods.

In-pipe bristled micromachine

This paper deals with in-pipe micromachine, which moves in pipes with inner diameter under 25 mm. The micromachine locomotion principle is based directional friction force between bristle tip and pipe wall. At first we have theoretically analysed the locomotion principle. The next part consist of analysis of bristle tip connection with inner pipe wall. Finally, the analysis is supported with experiments.

Modeling of a snake-like robot rectilinear motion and requirements for its actuators

The paper deals with a rectilinear motion of a snake-like robot. At first the various kinds of friction models are discussed and then the mathematical model of rectilinear snake-like robot locomotion is established. Considering the isotropic Coulomb´s friction model the average velocity of N-mass system is derived. Further the average velocity dependence on the number of used masses N is described through the graph. From the equation of average velocity there is the optimal number of masses N established. In the paper there are two alternative sequences of motion considered and subsequently through the simulations they are compared to each other. Finally the requirements concerning the linear actuator between two masses are described.

Snake Robot Movement in the Pipe Using Concertina Locomotion

Inspection tasks of pipes or channels are part of the engineering practice. In the past there were investigated conventional approaches like wheeled-based mechanisms. This paper deals with unconventional approach - snake robot moving in the pipe. In the paper locomotion pattern of concertina is introduced and subsequently kinematic model of concertina locomotion is established. Main requirements and conditions of presented locomotion pattern are stated. Using software Matlab the kinematic model is simulated according designed locomotion pattern in order to verify the kinematic model. For experimental purposes the experimental snake robot – LocoSnake is used. Simulation and experiment are compared and evaluated.

Methodology of contact stress analysis of gearwheel by means of experimental photoelasticity.

The subject of this paper is the analysis of contact stresses that occur between the teeth of a gear. The analysis was carried out by means of reflection photoelasticity, which is an experimental method rarely used in this field. Contact stresses assessed in the experiment are compared with values assessed through an analytical calculation while using the Airy stress function or Hertzian relations.

Miniature Mobile Bristled In-Pipe Machine

The in-pipe machine locomotes in the pipe on the principle of differential friction between the bristles and the pipe wall during the movement of the bristle forwards and backwards. These bristles are very important construction parts of the in-pipe machine. In order to define the locomotion of movement it is important to know the force situation on the bristles caused by its high deformation in the pipe. The determination of force situation brought us to a non-linear differential equation of the second order and determination of conditions for its solution. By this equation it is possible to describe the outline of large deformations of the construction part and to determine the forces affecting this part.

Simulation Model of Manipulator for Model Based Design

The subject of creation of simulation and mathematical models is nowadays more and more current and its application is in almost every aspect of life. The article deals with compiling a mathematical model of a pivoting arm using Lagrange equations of the second kind. Subsequently, the model will be created in the simulation program Matlab/Simulink. The simulation model will as well be assembled in the program Adams. The results of these simulations will be compared in the conclusion. This article presents a procedure for resolving a mechanical system from the beginning, from creation of a mathematical model through creation of a simulation model up to evaluation of the simulation results. This paper presents a procedure for resolving mechanical system from the beginning. Thus, it is done by creating a mathematical model through the creation of a simulation model to evaluate the results of the simulation. According to these simulations will produce a working model of the manipulator, which could be used for teaching purposes.

Concept of Locomotion Mobile Undercarriage Structure Control for the Path Tracking

The article deals with the proposal structure of undercarriages mobile robot GTR 2010 control. Functional model of the undercarriages mobile robot GTR2010 should be able to carry out active tracking of desired path for achieving a goal and get over obstacles in unstructured environments.

Algorithm for determining static characteristic on electromagnetic actuator for rectilinear locomotion structure of a snake-like robot

This work deals with the determination of static characteristics of electromagnetic actuator. Electromagnetic actuator is designed as drive for rectilinear locomotion structure parts of snake-like robot. Static characteristics are determined by the solving of a non-linear problem of the actuators magnetic circuit in a ferromagnetic cores particular positions and at the different fluxional rates of the coil. Static characteristics are represented by a L induction, magnetic force affecting ferromagnetic core Fm. For the calculation of the coil induction L is used the power of magnetic field. Magnetic field power is calculated by using Maxwell stress tensor and differential formula by a numeric derivation way.

Intelligent in-pipe machine adjustable to inner pipe diameter

The paper concerns to area of in-pipe locomotion. Traditional conceptions of in-pipe machines tend to wheels slipping or self-blocking. Several design stages of improved in-pipe machine are shown. Design of in-pipe machine coming from conception of computer controlled electromechanical device. Final design solution will be able to locomote inside pipe with variation of inner diameter in range from 100 to 200 mm with automatically adjustment to pipe diameter.