Adaptive Degrees of Freedom for Shared Control of Assistive Robots

Abstract

Robots have become a prominent part of our daily lives, be it as a versatile tool at work or as an obedient household helper. This is especially exciting for people with physical limitations, since designated assistive robots harbour a large potential to enhance their users' autonomy and quality of life. Following this line of thought, the field of assistive robotics introduces mechanical assistants to people who would otherwise struggle with activities of daily living. However, this necessitates adequate and potentially personalised control methods.

Focusing on wheelchair-mounted robotic arms, this thesis discusses currently available options, evaluates directly applicable manual alternatives, and proposes a novel shared control based on adaptive degrees of freedom (DoFs). With a participatory design, each element is developed and evaluated in close collaboration with the target group, thus allowing for appropriate integrations and realistic assessments.

For the contemporary manual analysis, users evaluated the manufacturer-provided input device in comparison to a gamepad, 3D mouse, and a command-based voice control. Here, the participants expressed an eagerness for personalised adaptability, as well as an explicit willingness to train in the use of more complex but capable systems, such as a 3D mouse.

Heeding this, this thesis introduces the novel shared control approach of Adaptive DoFs: A camera-based sensor system probabilistically analyses the current situation to generate the most likely directions of robot motion and maps these to the user's input device, effectively replacing the classically available cardinal DoF. For the user, this feels like the system anticipating their next move and providing support without taking over control.

An implementation of this proposed adaptive control was thoroughly evaluated with the target group, using e.g. smart glasses, showcasing high user acceptance with a steep learning curve and high success rates.