(Georgia Institute of Technology, 2012-09)
Hawkins, Kelsey P.; King, Chih-Hung; Chen, Tiffany L.; Kemp, Charles C.
Hygiene and feeding are activities of daily living (ADLs) that often involve contact with a person's face. Robots can assist people with motor impairments to perform these tasks by holding a tool that makes contact with the care receiver's face. By sensing the forces applied to the face with the tool, robots could potentially provide assistance that is more comfortable, safe, and effective. In order to inform the design of robotic controllers and assistive robots, we investigated the forces able-bodied people apply to themselves when wiping and shaving their faces. We present our methods for capturing and modeling these forces, results from a study with 9 participants, and recommendations for assistive robots. Our contributions include a trapezoidal force model that assumes participants have a target force they attempt to achieve for each stroke of the tool. We discuss advantages of this 3 parameter model and show that it fits our data well relative to other candidate models. We also provide statistics of the models' rise rates, fall rates, and target forces for the 9 participants in our study. In addition, we illustrate how the target forces varied based on the task, participant, and location on the face.
(Georgia Institute of Technology, 2011-03)
Chen, Tiffany L.; King, Chih-Hung; Thomaz, Andrea L.; Kemp, Charles C.
By initiating physical contact with people, robots can be more useful. For example, a robotic caregiver might make contact to provide physical assistance or facilitate communication. So as to better understand how people respond to robot-initiated touch, we conducted a 2x2 between-subjects experiment with 56 people in which a robotic nurse autonomously touched and wiped the subject's forearm. Our independent variables were whether or not the robot verbally warned the person before contact, and whether the robot verbally indicated that the touch was intended to clean the person's skin (instrumental touch) or to provide comfort (affective touch). On average, regardless of the treatment, participants had a generally positive subjective response. However, with instrumental touch people responded significantly more favorably. Since the physical behavior of the robot was the same for all trials, our results demonstrate that the perceived intent of the robot can significantly influence a person's subjective response to robot-initiated touch. Our results suggest that roboticists should consider this factor in addition to the mechanics of physical interaction. Unexpectedly, we found that participants tended to respond more favorably without a verbal warning. Although inconclusive, our results suggest that verbal warnings prior to contact should be carefully designed, if used at all.
(Georgia Institute of Technology, 2010-10)
King, Chih-Hung; Chen, Tiffany L.; Jain, Advait; Kemp, Charles C.
This paper describes the design and implementation of a behavior that allows a robot with a compliant arm to perform wiping motions that are involved in bed baths. A laser-based operator-selection interface enables an operator to select an area to clean, and the robot autonomously performs a wiping motion using equilibrium point control. We evaluated the performance of the system by measuring the ability of the robot to remove an area of debris on human skin. We tested the performance of the behavior algorithm by commanding the robot to wipe off a 1-inch square area of debris placed on the surface of the upper arm, forearm, thigh, and shank of a human subject. Using image processing, we determined the hue content of the debris and used this representation to determine the percentage of debris that remained on the arm after the robot completed the task. In our experiments, the robot removed most of the debris (>96%) on four parts of the limbs. In addition, the robot performed the wiping task using relatively low force (<;3 N).