Wheelesley : A Robotic Wheelchair System: Indoor Navigation and User Interface Holly A. Yanco Woo Hyun Soo DESC Lab.

Introduction Goal of the Wheelesley project A robotic wheelchair system that provides navigational assistance which allows its user to drive more easily and efficiently. Two basic requirements First, robotic wheelchair must navigate safely for long periods of time. Second, it must interact effectively with the user. The Wheelesley system takes over low-level navigation control, – allowing the user to give higher level directional commands.

Related Work This research differs from previous research in robotic wheelchairs in four ways. First, it will be able to navigate in indoor and outdoor environments. Second, it is a reactive system and does not require maps or planning. Third, interaction between the user and the wheelchair is investigated. Finally, the system has an easily customizable user interface.

Robot Hardware The robot has a processor For sensing the environment, –12 SUNX proximity sensors (infrared) –4 ultrasonic range sensors –2 shaft (wheel) encoders and 2 Hall effect sensors. A Macintosh Powerbook –is used for the robot ’ s graphical user interface. The focus was –On creating an interface that could be easily customized for various users and their access methods.

A Navigation System for Indoor Environments A robotic wheelchair must interact with its user. There are two types of control: Low-level control involves avoiding obstacles and keeping the chair centered in a hallway. High-level control involves directing the wheelchair to a desired location. In the Wheelesley system, The user gives the high-level commands through the graphical user interface.

Indoor navigation relies on –The infrared sensors Give binary readings that indicate if something is about one foot from the sensor. –The sonar sensors Return distance information. –The Hall effect sensors are mounted on the wheelchair ’ s bumper and are used as a last resort. The robot is able to traverse long hallways without requiring user corrections. A Navigation System for Indoor Environments

Graphical User Interface The Wheelesley system solves The adaptation problem through the addition of a general user interface that can be customized for each user. The interface has been customized for two access methods. The first is an eye tracking device called EagleEyes. The second is a single switch scanning device. There are three control modes. Manual mode joystick mode interface mode

The original user interface screen The rectangular bars represent the sonar sensors. The infrared sensors are represented by circles with a line. Two different access methods: –Eye tracking and single switch scanning.

Access Methods Access methods are devices, Used to enable people to drive wheelchairs or control computers. –The default is a joystick. –A switch or group of switches. –A sip and puff system. –Single switch scanning. –The method of last resort.

Customizing the User Interface for EagleEyes EagleEyes is a technology, That allows a person to control computer through five electrodes placed on the head. The electrodes measure the EOG Custom software interprets signals and translates them into cursor coordinates on the screen.

Single switch scanning Is the access method of last resort Consists of a switch and a control panel with four lights for four directions The user clicks the single switch when the control panel shows the desired direction. Robotic assisted control Can improve driving by correcting drift automatically and avoiding obstacles. User tests determined That an obstacle course can be completed in less time and with less effort than without. Customizing the User Interface for Single Switch Scanning

Future Work and Summary A robotic wheelchair Must be able to navigate in both indoor and outdoor environments. Will automatically select indoor or outdoor mode using an indoor/outdoor sensor currently in development. A vision system for outdoor navigation is being developed. In the initial work towards the goal An indoor navigation system and a graphical user interface have been developed.