# Conceptual Design of BCI for Mobile Robot Control
## 1 Introduction  
At the end of the 20 th century, leading research centers around the world, i.e., Graz University of Technology, Austria; University of Rochester, USA; EPFL, Switzerland; etc., initiated research aimed at developing Brain Computer Interfaces--BCI, which provide communication between a computer and a human brain. In the presented work, we deal with the conceptual design of the laboratory-level BCI system created in Process Control Dept., AGH University of Science and Technology, Poland [1,2]. This BCI system consists of measuring and computer control subsystems, mobile robot (MR) and man-operator. All the subsystems are briefly described in this paper. Formal basis for the Conceptual Design (CD) of the BCI system and its brief conceptual model are presented in the first part (Sections 2.1 and 2.2) of the paper. The results of the BCI system detailed design and MR control processes are described in the second part (Sections 2.2 and 2.3). A review of the literature on BCI systems will not be given in the paper since the focus of this work is to apply the Hierarchical Systems technology [2] to the BCI system design, which is a novel concept to this area of research. Concerning the first part, the conceptual model of BCI being created at the conceptual design phase [2] must be coordinated with numerical and geometrical systems, taking into account connected mechanical, electro-mechanical, electronic, computer, and biological subsystems of BCI biomechatronic system. Besides, a conceptual model, which will be implemented in systems coordination (design and control), should describe all the subsystems, the mechanism of their interaction, technology ofsubsystems integration in the structure of higher level, and the system environment in common formal basis. Therefore, creation of a BCI conceptual model that will meet all the above mentioned requirements is a task of a high importance. This task is crucial for mechatronic systems and computer aided design (CAD) systems in particular [3]. According to the above formulated requirements, the conceptual model implemented in BCI design must be a hierarchical construction that connects any level BCI subsystem with its lower and higher levels. Therefore, Hierarchical System (HS) [4], with its standard block aed [5; 6; 7; 8; 9], which meets all of the above requirements for the BCI conceptual model, was selected as the formal basis for BCI system conceptual design (Section 2) in this paper. An overview of the other conceptual design methods is presented in the monograph [9] available online. An issue of interest in this study was to verify whether HS technology and the conceptual model could be implemented in the conceptual design of the BCI system taking into account all the subsystems (mechanical, electromechanical, electronic, and biological) of a BCI-MR biomechatronic system. The results of this study are given below. Concerning the second part, the BCI system detailed design for performing MR control processes is executed in a laboratory environment. The purpose of this work is to control MR utilizing bioelectric activity of the human brain. This study was based on the use of visually evoked potentials, which are the brain's response to retinal light stimulation. The possibility to use the BCI system by people with disabilities is one of the tasks of this work. The desired characteristics of the BCI system are real-time efficient operation, safety and ease of use. Providing real-time control without response delay requires proper optimization of the implemented algorithm and reduction of hardware requirements where possible. Ease of use can be achieved with high-frequency visually evoked potentials. In such conditions, a person will not be exposed to excessive noticeable stimuli of flickering light. On the other hand, the detection of the higher frequencies of electroencephalogram (EEG) signals is complicated [10]. Another important characteristic is safety.