Event Location: NSH 1507

Abstract: Robots that can operate in human environments in a safe and robust manner would be of tremendous benefit to society in general, due to their immense potential as assistance providers to humans. However, robots to this day have seen limited application outside of the industrial setting in environments such as homes and hospitals. We believe a very important factor preventing the cross over of robotic technology from the factory to the house is the issue of safety. The safety issue is usually bypassed in the industrial setting by separation of human and robot workspaces. Such a solution is clearly infeasible for our application domain.

Unlike industrial robots, the environment is largely unstructured for a domestic robot. Coupled with the lack of sensing and perception capabilities this translates to significant safety hazards for a human in the robot’s workspace. Fortunately, unlike industrial applications domestic applications are usually low precision tasks. Therefore domestic robots call for a new design paradigm where operational safety is the primary concern and task accuracy/precision though important are secondary.

Our approach towards addressing this new design paradigm is to utilize soft robots. We are interested in developing a general class of robots which possess compliance that is distributed throughout their structure rather than localized at only the joints or at their surface. Soft structured robots can minimize injury risks due to unexpected human-robot interactions and therefore offer the possibility of faster and more agile systems working in human environments. Two potential types of soft structured robots have been explored: a) continuum manipulators and b) inflatable manipulators.

While the idea of continuum manipulators is not new, we have attempted to apply such manipulators to human-interaction tasks. The second novel approach has been that of utilizing ‘inflatable manipulators’. Inflatable structures offer tremendous advantages in terms of high strength to weight ratios in addition to distributed compliance due to their flexible structure and this has positive implications for safety. As inflatable structures have not been explored to a great extent for use in robots considerable effort has been devoted to the development and prototyping of an inflatable manipulator. The inflatable manipulator resulting from this effort has 2 DoFs and is equipped with an inflatable gripper at its end and is capable of carrying a payload of 5N at its end. Initial impact tests have revealed minimum risk of injury even at considerable end effector velocities.

I propose to demonstrate the ability of an inflatable manipulator to safely and robustly carry out a task involving close human-robot interaction. I will utilize a control-design optimization methodology to synthesize the geometric, dynamic and pneumatic features of the proposed manipulator to satisfy requirements of safety and performance. Control strategies for the arm shall be developed which account for both intended and unintended human interaction.

Committee:Christopher G. Atkeson, Chair

Howie Choset

Steven H. Collins

J. Edward Colgate, Northwestern University