A brain-neuronal computer interaction system can provide a communication channel for severely disabled people or a supplementary control channel for able-bodied subjects. In this paper, a physiological hybrid P300-based speller that uses a modified stimulus presentation paradigm-the half checkerboard paradigm (HCBP)-is evaluated. The speller uses electrooculography and electroencephalography signals for selecting alphanumeric characters or commands arranged in an 8 × 9 matrix. In this study a group of subjects, who can voluntarily gaze at a target, used the checkerboard paradigm- and HCBP-based spellers in a counterbalanced fashion for comparing their performances under a series of online tests. A 16-character-long text was spelled by each subject, while a 13-character-long text was used for calibrating the system. By using the HCBP, the time required for spelling one character is reduced, resulting in higher information transfer rates. The results suggest that the HCBP has the potential to provide a more effective P300 paradigm with a major importance for people with neuromuscular diseases and also for healthy people as a supplementary communication channel.
Abstract. Basketball has grown into an international sport played and watched by millions of people. This paper describes the implementation of a virtual basketball accelerator. The main purpose of our study was to devise an application that could literary help players in practicing a free throw game indoors. In the development of this project we used Matlab, XVR and 3ds Max. The Matlab trajectory is simulated considering the development of a realistic behavior. The data acquisition from the trackers is adapted both for magnetic and optical markers, therefore extending its usability. The coordinates are then sent via UDP to the XVR environment, which draws the moving parts accordingly. The overall performance is improved by paying a great deal of attention to details.
Abstract:In this paper is presented an experimental study that aims to compare the depth perception of virtual prototypes in immersive virtual environments with the depth perception of CAD models using 2D LCD display. First, a multipurpose solution of a large-scale interactive multi wall projected virtual environment named Holo-CAVE is described and then the conducted experiments are presented. The experiments carried out highlight that perceived depth values estimated for virtual prototypes are significantly influenced by the 3D stereoscopic visualization. Another interesting result of the study is that the estimated depth accuracy increases with the depth size that has to be perceived. The results of experimental study illustrate that the use of immersive stereoscopic visualization is useful during Computer Aided Design related activities.
Abstract. This paper proposes two paradigms for controlling a robotic arm by integrating Electrooculography (EOG) and Electroencephalography (EEG) recording techniques. The purpose of our study is to develop a feasible paradigm for helping disabled persons with their every-day needs. Using EOG, the robotic arm is placed at a desired location and, by EEG, the end-effector is controlled for grasping the object from the selected location. Simple algorithms were implemented for detecting electrophysiological signals like eye saccades, blinking and eye closure events. Preliminary results of this study are presented and compared.
Link to this article: http://journals.cambridge.org/abstract_S0263574714000149How to cite this article: Doru Talabă (2015). Mechanical models and the mobility of robots and mechanisms.
SUMMARYMobility is a fundamental parameter of mechanisms expressing in a qualitative manner their kinematic and dynamic properties. The mobility formulae presented in literature take into consideration some of the structural entities, such as bodies, joints, constraints, closed loops, and space characteristics; however, the specific mechanical model that has traditionally been at the origin of the mobility criteria themselves is incompletely specified and, even then, only implicitly. In this paper, we propose a classification of the mobility criteria based on the known dynamic models. While all known mobility criteria have been associated with a specific dynamic model, some particular, less used dynamic models (like natural coordinates and multi-particle models) suggested new mobility criteria models. The associated mechanical model for each category of mobility criteria allows a qualitative assessment of the kinematic and dynamic sets of equations to be formulated in later stages of analysis. A simple multi-loop mechanism is taken as an example just to illustrate the mobility calculation and qualitative assessment of the kinematic and dynamic models in each case. Based on the proposed classification of the mobility formulae, an assessment is made with particular regard to their applicability to overconstrained mechanisms.
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