Vladimir M. Petrović

Virtual laboratories for education in science, technology, and engineering

Within education, concepts such as distance learning, and open universities, are now becoming more widely used for teaching and learning. However, due to the nature of the subject domain, the teaching of Science, Technology, and Engineering are still relatively behind when using new technological approaches (particularly for online distance learning). The reason for this discrepancy lies in the fact that these fields often require laboratory exercises to provide effective skill acquisition and hands-on experience. Often it is difficult to make these laboratories accessible for online access. Either the real lab needs to be enabled for remote access or it needs to be replicated as a fully software-based virtual lab. We argue for the latter concept since it offers some advantages over remotely controlled real labs, which will be elaborated further in this paper.We are now seeing new emerging technologies that can overcome some of the potential difficulties in this area. These include: computer graphics, augmented reality, computational dynamics, and virtual worlds. This paper summarizes the state of the art in virtual laboratories and virtual worlds in the fields of science, technology, and engineering. The main research activity in these fields is discussed but special emphasis is put on the field of robotics due to the maturity of this area within the virtual-education community. This is not a coincidence; starting from its widely multidisciplinary character, robotics is a perfect example where all the other fields of engineering and physics can contribute. Thus, the use of virtual labs for other scientific and non-robotic engineering uses can be seen to share many of the same learning processes. This can include supporting the introduction of new concepts as part of learning about science and technology, and introducing more general engineering knowledge, through to supporting more constructive (and collaborative) education and training activities in a more complex engineering topic such as robotics. The objective of this paper is to outline this problem space in more detail and to create a valuable source of information that can help to define the starting position for future research. State of the art in dynamics-based virtual laboratories.Defining the criteria for critical evaluation of existing technologies.State of the art in virtual worlds.Future advances in the field of virtual-world based laboratories.

Balance Analysis of the Mobile Anthropomimetic Robot Under Disturbances - ZMP Approach

Throughout the history of technological progress, attempts have been made to build a machine that looks and behaves like humans. This paper presents a semi-anthropomimetic robot. The robot structure consists of a human-like upper body mounted on a mobile platform (mobile base, cart). The robot uses the three-wheeled mobile platform with two driving wheels and one passive (caster) wheel. The configuration and model of the upper body are represented as an anthropomimetic, compliant robot with antagonistically coupled drives. Robust control is evaluated in order to ensure stability of the robot position. The aim of this work is not the synthesis of control, but rather the examination of the limits of the adopted robot control strategy and the robot behaviour under disturbances (analysis of tip-over stability). The paper analyses both disturbances from the cart motion and external disturbances due to interaction with the environment (external impulse and long term external force). In order to analyse the balance of the robot and to avoid tipping over, different situations are tested and the appropriate dimensions of the cart are estimated (relying on the ZMP calculation).

Development of Virtual Laboratory for Mechatronic Systems

Laboratory experimentation is one of the key issues for the successful education and research. This applies particularly to engineering sciences, where experimental setups provide a deeper understanding of theoretical principles. If we consider this, as well as the fact that e-learning and distance learning became widespread in the last decade, it is not surprising that virtual laboratories appeared as a new experimentation concept. In this paper we will present the Virtual Laboratory for Mechatronic Systems (VLMS). VLMS currently consists out of two parts - robotics module and hydraulics module. Detailed description of each one will be provided in the paper. Dynamics of each particular laboratory device is mathematically modeled and simulated. Realistic virtual user interfaces are provided and finally 3D CAD graphics is used to provide an appropriate visualization.

Optimalna kartografska konična projekcija – analiza slučaja za geografski teritorij Srbije

Original scientific paper The article deals with finding the optimal map conic projection which, according to the criteria of the minimum of distortions, would be more appropriate than the available and, up to the present point in time, generally used conic map projections. Apart from the best map projection, the paper also describes other conic projections still used in the official cartography of Serbia. In the paper, the size of the deformations is analysed and shown in case of the Modified polyconic projection and the Lambert conic projection on the example of a geographical map at scale 1:1000 000. Namely, the size of the linear deformations is analysed and shown in all cases. One of them, the fifth example of the Lambert conformal conic projection, is the most favourable in terms of size and distribution of the deformations upon the entire surface of mapping. Examples of real conformal conic projections are made with numerical procedures in the program package MATLAB.