An Assistive Navigation Paradigm For Semi-autonomous Wheelchairs Using Force-feedback And Goal Prediction

As computer technology advances and facilitates an increased amount of autonomous sensing and control, the interface between the human and autonomous computer systems becomes increasingly important. This applies in particular in the realm of service robotics where robots with increasing levels of autonomy are constantly interacting with human users and where it is paramount to have an efficient way to convey user intentions and commands to the robot system, integrate them into the robot's action and control, and to indicate robot control choices to the user in a "natural", intuitive way. One particular example where semi-autonomous operation of a vii system has been shown to be of major benefit is in the case of advanced wheelchairs which benefit from local autonomy and fine control capabilities of sensor-driven computer control systems but have to be under the higher-level control of the disabled user. This thesis investigates technologies aimed at facilitating the integration of such autonomous path planning capabilities with intuitive human control using a forcefeedback interface. While force-feedback has been applied to artificially intelligent wheelchairs, only the surface of the capabilities of this interface mechanism has been scratched. This thesis seeks to expand upon the earlier work in this field by developing the idea of force-feedback not just as a tool for obstacle avoidance, but also as a tool for guiding the wheelchair user to their goal. To this point, harmonic function path planning has been integrated to create a new, more robust force-feedback paradigm. A force-feedback joystick has been used to communicate information from the user to the robot control system which uses this to infer and interpret the user's navigation intentions as well as from the harmonic function-based autonomous control system to the user to indicate the system's suggestions. To demonstrate and evaluate its capabilities his new paradigm has been implemented within the Microsoft Robotics Studio framework and tested in a simulated mobile system, with positive results.