Study On Brain-Computer-Interface Techniques In Intelligent Wheelchair

HMI (Human-Machine-Interface) also called Human-Computer Interaction (HCI) techniques or User Interface, stand for the interactional area between Human and Machine. Intelligent wheelchair, assembling Pattern Recognition,Multi-sensor data fusion and multimodal human-computer interaction techniques, improved users'independent action by various HCI and automatic navigation function, so has broad application prospects. One of the key techniques in intelligent wheelchair is Human-Centered; it could achieve real harmony with the user. As a one of the HMI, BCI (Brain-Computer-Interface) techniques gradually make the EEG signals in communication with a computer or other device possible. Meanwhile, it inaugurated an effective communication and control channel with outside world.According to the existing condition of BCI research, in terms of the fact that changes in the alpha component of EEG during eye's open and closure existing among most people who has normal brain nerve can act as a reliable and fast electronic switches and combining the wheelchair control method, this research designed an intelligent wheelchair system based on BCI, it can rapidly and highly reliably control the wheelchair needless of training or need a little only.This system consisted of signal gathering,signal processing platform,control panel and interface control circuit. Firstly, the user produced EEG that contained relevant control information by the control panel. Secondly, the signal was imported to computer after amplified and filtered through preamplifier and A/D conversion through signal acquisition card. Thirdly, computer finished a series of work of signal processing on Labview platform such as filter, noise removal, RMS smoothness and evenness, comparing to the threshold voltage, producing pulse control signal and so on. Finally, corresponding control signals transformed through interface circuit were sent to the wheelchair. In order to provide an experimental basis and confirm BCI system parameters, this research performed a series of experiment by eight subjects: 1, Acquisition of the source signal in different locations and compare to its control effect provide a foundation to the electrode-cup design; 2, Determining the principle for selecting the threshold voltage on basis of pseudo-potential in a different threshold voltage conditions; 3, Data statistic of trigger time determined the flicker time selecting rule of the cycle lights.Finally, all subjects attended four group single direction wheelchair operations and advanced travel experiment to test the performance of the system. It was obviously seen from the results that eight subjects could successfully and steadily finish the most operations with preferable success rate and stability. It also proved that this BCI system is feasible and has potential application value.