Soft robotic finger to replace doctor's finger during medical examinations

A research team from the University of Science and Technology of China has developed a soft robotic finger with a keen sense of touch for routine examinations. For example, it can measure a patient's pulse and feel for abnormal lumps. The technology can help detect diseases such as breast cancer at an early stage and relieve patients of the discomfort of invasive examinations.

The soft robotic finger consists of a silicone material in which conductive fiber coils are inserted. The coils act on each individual air chamber housed in the finger, which serve as bending actuators to move the finger.

A twisted liquid metal fiber is attached to the tip of the finger. Using a current flow, the researchers can measure how far the finger bends when it touches an object and what force is exerted on the fingertip. This happens in real time, as the scientists explain in the study "Toward human-like touch sense via a bioinspired soft finger with self-decoupled bending and force sensing", which was published in Cell Reports Physical Science. The finger can thus perceive the properties of an object as well as a human finger.

"Humans can easily detect the stiffness of different objects by simply pressing them with their finger," the researchers write. "Since the [device] is able to detect both bending deformation and force at the fingertip, it can detect stiffness similar to our human hand by simply squeezing an object."

Very sensitive

The scientists tried out the finger in various laboratory tests. They initially found it to be highly sensitive. For example, the finger was able to respond to the touch of a bird's feather with force feedback. The researchers also tested the soft robotic finger on a silicone foil in which three harder lumps were embedded. The finger was able to identify the hardenings in a similar way to a doctor examining a patient.

The research team then mounted the artificial finger on a robotic arm. It could be moved in such a way that it could find and measure the pulse on a patient's wrist.

The researchers now want to make the finger even more flexible with additional sensors, among other things, so that it can move in more directions than before. This should enable it to carry out effective and efficient medical examinations in the near future. The scientists' aim is to build an intelligent, dexterous hand that, together with a sensor- and muscle-controlled robotic arm, can imitate the functions of human hands. According to the researchers, the hand could then be used as a "robo-doctor" for automated routine examinations in hospitals.

(olb)