Assistive Technology: Design and Implementation of an Eye Tracking Based Electric Wheelchair Control System for Children with Cerebral Palsy
Authors: Hernandez Katherine , Salinas Veronica , Torres Hugo , Estevez Fernando , Almeida- Galárraga Diego , Alvarado Cando Omar 
Published: April 2022

Cerebral palsy (CP) is a set of non-progressive alterations which affect muscle tone, posture, and movement. CP is produced by a brain injury or malformation in one or more brain areas that control movement. It is the most common motor disability in childhood. It affects the autonomy and socialization of children and generates great pressure on the family; therefore, children with CP require the aid of a wheelchair, which is usually driven by the user or pushed by another person. Even using a wheelchair controlled with a joystick becomes complicated because it depends on the control of gross and fine motor skills. Then, there is necessary a more amicable and accessible way to control a wheelchair. Since the ocular muscles are one of the few that still fulfill their function in people with CP, in this paper, we present the design and implementation of an eye-tracking-based electric wheelchair control system for children with spastic and mixed CP. This system includes a low-cost electric wheelchair built with PCV tubes, a Microsoft Surface Pro Tablet where the software is running, and a PCEye Mini device used to monitor the gaze. The PCEeye Mini sends the signs to the mainboard that controls the electric motors, allowing the children to steer the wheelchair by themselves using their gaze. The software has three components: the first manages the application data, the second represents the model graphically displayed on the screen, and the third receives and manages user inputs. The application has three interfaces for the start of the system that children can access since the home screen, and each one gives the user different control system parameters options. Eight children with CP participated in three experiments to validate the efficiency and safety of the system. Each experiment was developed in an internal and external environment with three different floor soils: cement, ceramic, and wood. The results showed a 100% efficiency and safety of the system for children use. The calibration process was fast and simple, the activation of directional arrows on the screen with the gaze gave 100% performance, the power consumption did not show a difference between the type of floor, and the electric wheelchair did not slip on any floor. The software maintained stable communication with the hardware through a serial communication protocol, allowing a correct execution of the commands. This work shows that the implementation of the eye-tracking technology in the electric wheelchair works successfully. This system operates effectively and is easy to control for children with CP, improving the children’s autonomy in terms of mobility. This software can be implemented on any PC, and more functions can be added to the same software without affecting its performance. This developed system offers an intelligent and different option to help children with motor deficits, which is a great contribution to society.