Robot's tactile sensors in fingers seek to help surgeons operate
Robot's tactile sensors in fingers seek to help surgeons operate
Keywords: Robots, Sensors
Realising that when a person reaches to pick up an object, tactile sensors in the fingers send information to the brain that can instantaneously ascertain the object's weight and slipperiness, Japanese scientists are now exploring the distinct possibility that the sensor's fingers can play a substantial part in– as one says – "developing a surgeon's touch. The brain has sent signals to the muscles so that the proper amount of force is used during the lifting."
At prestigious Keio University in Tokyo, it is reported that a team has developed a robot arm with fingers that have the same delicate sensitivity as human fingers. The team has developed a robot arm that can lift objects such as a coffee cup, but it is now working to improve the technology to develop a tactile sensor robot arm for use in medical applications for very fine control of scalpels in a surgeon's hand.
A prototype robot arm has finger extensions that measure some 45cm long and wide and about 6cm thick. The fingers close on either side of an object to lift it up. Sensors at the tips detect the weight and the slipperiness of the object and transmit this information to a computer, which instantly calculates how much force the fingers need to apply for lifting. The prototype can lift objects weighing up to roughly 800 grammes.
The robot fingers are made of silicone rubber and have a rounded shape like human fingers, with the inner sides covered by a number of strain sensors. When an object is grasped, the inside parts of the fingers are depressed, and the extent of this change provides a way to determine the object's weight and slipperiness. The robot, moreover, can distinguish an empty paper cup from one filled with liquid, and an object made from metal from one made from gritty stone.
Most robot arms use some mechanism to determine an object's weight before it is picked up, and this normally involves sensors that determine an object's hardness when it is grasped with a certain amount of power. The robot employs this information to calculate how much force is needed to lift the object,making sure it is not dropped when it is picked up.
Although this technique is good enough right now for simple tasks and for lifting reasonably large objects, it is not sufficiently complicated or delicate enough for the task of guiding a scalpel during surgery. What is needed, says a Keio University technician, "is a robot arm that can evaluate both the weight and the slipperiness of an object at the same time and with the same high degree of sensitivity as human fingers."
