Christian Bartolein

Analysis of Human Information Acquisition Behavior for Natural Gaze-Based Wheelchair Control

Especially for severely disabled people, a powered wheelchair is an important means to participate in societal life and live as far as possible independently. To achieve this goal for users, who cannot operate their wheelchair with the traditional joystick or specialty controls, methods have been developed to enable steering the wheelchair on the basis of the users gaze behavior. While existing approaches require the user to adapt his/her gaze behavior to match the characteristics of the human-technology interaction and/or only provide reasoning about the desired motion direction of the user, the conducted study gives crucial input about the relationship between the gaze behavior of wheelchair users and the - from the user - desired goal position as well as his/her anticipated mission. Implications for a natural gaze-based assistance system for electrically powered wheelchairs are drawn, which allows reasoning on the users behavioral goal position and his/her current mission.

Quantitative Comparison of a Joystick and a Two-Switch Control Mode When Steering a Wheelchair through a Realistic Environment

The following paper investigates the efficiency and the usability of two ways of steering a powered wheelchair, i.e., the joystick and a two-switch control mode. To yield a high internal validity of the results and receive data, which can be used for benchmarking, a repeated measurement design has been chosen and 23 participants steered the wheelchair in both control modes through a predetermined course. The resulting data shows impressively the superiority of the joystick mode and demonstrates that research on assistive technologies should focus on reducing the space required for rotating, the time required to reach a certain goal position, the number of input commands required to execute a behavior and also the usability especially of the two-switch control. Herewith, the current paper complements the existing case study reports and questionnaire data as the applied experimental set-up allows for tracing back the revealed effects on the manipulation of the control mode.

An Activity-Theoretic Approach to Intention Estimation

Abstract Traditional powered wheelchair control is especially for severely disabled people cognitively and physically demanding due to the high number of input commands necessary. An intention estimation behaviour, which considers the cognitive processes of the actor, is discussed as one way in order to significantly reduce the number of required input commands. For this purpose, a continuum of, from other researchers discussed modes of human behaviour is introduced as well as cognitive processes underlying this continuum of human behaviour. A study conducted with wheelchair users confirms major assumptions of the theory and allows drawing implications for realizing an intention estimation behavior considering the cognitive processes of the actors.