presented by:
SAIDULU USIRIKAYALA

---

[attachment=8768]
ELECTROOCULOGRAPHIC GUIDANCE OF A WHEELCHAIR USING EYE MOVEMENTS CODIFICATION
Abstract
 This paper presents a new method to guide mobile robots. An eye-control device based on electrooculography (EOG) is designed to develop a system for assisted mobility.
 Control is made by means eye movements detected using electrooculographic potential.
 Using an inverse eye model, the saccadic eye movements can be detected and know where user is looking.
INTRODUCTION
 Assistive robotics can improve the quality of life for disable people.
 Nowadays, there are many help systems to control and guide autonomous mobile robots.
 All this systems allow their users to travel more efficiently and with greater ease.
 In the last years, the applications for developing help systems to people with several
 To tell this work is included in a general purpose navigational assistant in environments with accessible features to
ELECTROOCULOGRAPHIC POTENTIAL (EOG):
The human eye is an electrical dipole with a negative pole at the fundus and a positive pole at the cornea. Figure 1 shows the ocular dipole. placed on the forehead. Figure 2 shows the electrode placement. Figure 2. Electrodes placement. The EOG signal changes approximately 20 microvolts for each degree of eye movement. In oursystem, the signal are sampled 10 times per second.
EYE MODEL BASED ON EOG (BIDIM-EOG):
Bidimensional dipolar model. The “Filter” block has as mission to eliminate the problematic associated to the electrooculographic signal. These problems are due mainly its variability, as well as possible interferences on the same one, such as blinking effect, facial movements and devices or interferences taken place by other biopotencials (EMG, EEG) or electrodes displacements on the skin
The process followed (using a linear saccadic eye model) can be observed in figure 8, where the results of a process in which the user made a secuence of saccadic movements from ±10º to ±40º in horizontal derivation are shown.
It is possible to see that the derivative of the electrooculographic signal allows us to determinate when a sudden movement is made in the eye gaze. This variation can be easily translated to angles
GUIDANCE OF A WHEELCHAIR USING COMMANDS GENERATED BY EYE MOVEMENTS DETECTEDUSINGELECTROOCULOGRAPHY
 The aim of this control system is to guide an autonomous mobile robot using the positioning of the eye into its orbit by means of EOG signal.
 In this case, the autonomous vehicle is a wheelchair for disable people.
 The EOG signal is recorded using Ag-AgCl electrodes and this data, by means of an adquisition system are sent to an onboard PC in which they are processed to calculate the gaze direction or eye movements.
Wheelchair. Figure 10. Guidance system. The mechanical structure of the wheelchair consists of a platform (measuring 100x80x58 cm and weighing approximately 35 Kg) on two motor wheels, with a radius Rd = 16 cm and separated by a distance D = 54 cm, have independent traction provided by two DC motors.
 There is a distributed control system based on LonWorks technology of ECHELON.
Conclusions
 This research project is aimed towards developed a usable, low-cost assistive robotic wheelchair system for disabled people.
 In this work, we present a system that can be used as a means of control allowing the handicapped, especially those with only eye-motor coordination, to live more independent lives