Electric wheelchairs, as mobile auxiliary equipment, improve the quality of life and self-independence of the disabled. The brain-computer interface (BCI) is used to establish a direct connection between the brain and the wheelchair, which adopts the electroencephalogram (EEG) signal to control the wheelchair. Compared with other types of BCI, the steady-state visual evoked potentials (SSVEP)-BCI is more suitable to control the electric wheelchair due to the advantages of higher information transmission rate (ITR), higher signal-to-noise ratio (SNR), and less training. However, the existing SSVEP-BCI electric wheelchairs need to be equipped with at least one personal computer to drive the visual stimulator and process EEG signals in real-time. As a result, the electric wheelchair system is complicated, bulky, and limited in movement flexibility, so it is difficult to popularize in real-life scenarios. Therefore, to improve the portability and applicability of the SSVEP-BCI electric wheelchair, a lightweight SSVEP-BCI system is needed, which should be as light and energy-saving as possible while meeting functional requirements.

This paper presents an embedded lightweight SSVEP-BCI electric wheelchair with a hybrid stimulator. A hybrid hardware-driven visual stimulator is designed, which combines the advantages of liquid crystal display (LCD) and light-emitting diode (LED) to achieve lower energy consumption than the traditional LCD stimulator. In addition, a lightweight BCI framework is designed to realize BCI program functions on the embedded platform for achieving similar performance as those on a personal computer. Experiments on real systems show that our embedded lightweight SSVEP-BCI electric wheelchair can be successfully operated by all eight subjects with a 93.9% average success rate of command operation. In addition, compared with the traditional LCD stimulator, the hybrid hardware-driven visual stimulator can save up to 27% of energy.

电动轮椅作为移动辅助设备，可以改善残疾人的生活质量和独立性。脑计算机接口（BCI）用于在大脑和轮椅之间建立直接连接，该接口通过脑电图（EEG）信号来控制轮椅。与其他类型的BCI相比，稳态视觉诱发电位（SSVEP）-BCI由于具有更高的信息传输率（ITR），更高的信噪比（SNR）的优势而更适合于控制电动轮椅，并且培训较少。但是，现有的SSVEP-BCI电动轮椅需要至少配备一台个人计算机，以驱动视觉刺激器并实时处理EEG信号。结果，电动轮椅系统复杂，笨重并且运动灵活性受到限制，因此很难在现实生活中推广。因此，为提高SSVEP-BCI电动轮椅的便携性和适用性，需要一种轻巧的SSVEP-BCI系统，该系统在满足功能要求的同时应尽可能轻便节能。

本文介绍了一种带有混合刺激器的嵌入式轻型SSVEP-BCI电动轮椅。设计了一种混合硬件驱动的视觉刺激器，它结合了液晶显示器（LCD）和发光二极管（LED）的优点，从而实现了比传统LCD刺激器更低的能耗。此外，轻量级BCI框架旨在在嵌入式平台上实现BCI程序功能，以实现与个人计算机上类似的性能。在真实系统上进行的实验表明，我们的嵌入式轻巧型SSVEP-BCI电动轮椅可成功用于所有八名受试者，平均指令操作成功率达93.9％。此外，与传统的LCD刺激器相比，混合硬件驱动的视觉刺激器可节省多达27％的能量。