Research And Implementation Of Brain-controlled Wheelchair System Based On Steady-state Visual Evoked Potentials

At present,with the increasing aging of the society and the occurrence of various natural disasters,diseases and traffic accidents,the number of the elderly and people with motor disabilities are increasing day by day.How to meet the needs of such people's autonomous movement and improve their quality of life is of great significance.As an important application of brain-computer interface(BCI)technology in real life,brain-controlled wheelchair(BCW)system establishes a new control pathway independent of peripheral nerve and muscle tissue and realizes wheelchair control by encoding and decoding brain signals of users,which makes it possible for patients with severe motor disabilities to control wheelchairs independently and achieve some needs of daily life.For this reason,this paper studies the key technologies of BCW system,and builds BCW system and simulated training system based on steady-state visual evoked potential(SSVEP),and carries out the test experiments.The research content of this paper mainly includes:(1)In accordance with the needs of BCW system construction,the BCI based on SSVEP is studied and designed.The sampled sinusoidal stimulation method is adopted to present the stimulus,and the scintillating stimulation is carried out according to the required frequency,which well evoked the SSVEP signal.The scheme of EEG acquisition and preprocessing is determined,including electrode selection,sampling frequency and filter parameter setting.At the same time,the filter bank canonical correlation analysis algorithm is used to detect the stimulus frequency of SSVEP signal effectively.(2)A BCW system based on SSVEP is designed and built.The system is realized from both hardware and software aspects.Users select control commands through BCI and transmit them to wheelchair through TCP/IP communication,so as to control wheelchair and meet the needs of movement.Finally,through the accuracy experiment and wheelchair control experiment,the good performance and practicability of the BCW system is verified.(3)In order to improve BCW control ability of users,a simulated training system is designed and implemented based on the designed BCW.Firstly,the two-dimensional grid map is modeled according to the indoor environment.According to the needs of training or practical application,the training scheme is designed,and A-star algorithm is used for path planning.The control modes and commands of wheelchair movement are designed,and the kinematic model of wheelchair is constructed.The commands of users are analyzed and obtained by BCI,and the simulated BCW is controlled to move in the simulated training scene according to the commands,and then realize the control training.Finally,the experiment and scoring mechanism are designed to measure the control performance of users and the training effect of the system.The experimental results show that the BCW control ability of the subjects is effectively improved under the training of the system.The training system provides an effective assistant method to promote the application of BCW.