While many movies and TV shows would have us believe that hospital sponge baths are only carried out by nurses at either end of the attractiveness spectrum, the reality is no doubt generally somewhere in between. In fact, I’m sure a lot of patients and even more nurses would prefer such tasks were handled by a robot. Researchers at the Georgia Institute of Technology seem to have reached the same conclusion and have developed a robot that can autonomously perform bed baths to keep bedridden patients clean.
For their work the researchers took Cody, a humanoid robot developed at Georgia Tech’s Healthcare Robotics Lab that comprises a Segway omnidirectional mobile base, two anthropomorphic arms with seven degrees of freedom and wrists equipped with 6-axis force/torque sensors. The end of the robot’s right arm is fitted with a specialized “bath mitt” and the robot gathers laser range data and images from a laser range finder and camera mounted above the robot’s torso.
After the robot scans the patient, the operator is presented with an image overlaid with a point cloud. Using a mouse, the operator selects two points that form the diagonal corners of a rectangular bounding box that the operator wishes to clean. After the robot transforms the points to 3D Cartesian points the robot autonomously executes the wiping behavior sequence using the right arm.
To test the robot the researchers commanded the it to wipe off a 1-inch square area of debris placed on the surface of a human subject’s upper arm, forearm, thigh, and shank. Using image processing the team determined the robot removed over 96 percent of the debris on four parts of the limbs and accomplished this using relatively low force.
Since the robot is making direct physical contact with a person, the team built in a number of safety features. The first is a run stop button that terminates the robot’s motion during the experiment in the event it makes “undesirable contact with the subject.” Secondly, the low stiffness of the robot’s joints was designed to soften the impact of the contact. Lastly, the robot’s controller attempts to maintain a downward force of three newtons against the subject’s body. If magnitude of the total force measured by the wrist force/torque sensor exceeds 30 newtons, the robot is commanded to stop.
The team says that currently an estimated 10.8 million Americans need personal assistance for normal daily activities and the rapidly aging population will see this number increase substantially in the coming decades. With the increasing need for more nursing and home-care services from the healthcare industry but studies have shown that there is a growing shortage of nurses.
For those with motor impairments, assistive robots that can perform hygiene tasks has also been identified as a high priority. The Georgia Tech researchers believe that the development of such robots could relieve the workload of nurses and provide greater independence and a better quality of life for those that need assistance.
The Georgia Tech team presented a paper on its assistive robot at the 2010 International Conference on Intelligent Robots and Systems (IROS 2010) last month.
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