Contact:
+91 93534 25649
Login & Learn
Human engineering is often seen as the pinnacle for technological achievement, be it the wheel, the steam engine or the space rocket. Human-engineering has also come a long way, especially in recent times. While the reality of fiction such as RoboCop is still beyond this present time, significant strides are currently being made in the field of understanding biomechanics and developing robotic biomechanics.
Research and innovation are key ingredients in innovative breakthroughs with key life-enriching applications that science and technology can bring to our lives. For instance, it was due to the endeavors of Gavriil Ilizarov, the Soviet doctor who developed the Illizarov fixator apparatus in the 1950s, that this writer’s leg could be saved from a destructive road accident. Such innovation can help improve or even save lives.
A pressure sensor embedded in the epoxy core picks up vibrations in the skin transmitted through the fluid. The fingerprints on the outside the skin actually amplify these vibration signals enormously. Temperature is sensed through a thermistor placed at the tip of the BioTac.
Myoelectric hands universally function off of sensing electrodes located on the residual limb. Their location is based on what muscles on the residual limb produce the strongest signals. The sensors are located on top of the skin, and pick up the electrical activity in a muscle when it flexes. Almost all myoelectric users have two of these sensors, one for opening the terminal device, and the other closing.
SynTouch have performed experiments where the sensations from the BioTac were relayed to me through a number of devices we call tactors. The three tactors were placed on my upper arm or bicep and each was correlated with a specific modality of the BioTac. An air pressure cuff similar to a sphygmomanometer was used to squeeze my arm to mirror a force applied to the BioTac. A small cellphone vibrator buzzed on my skin to emulate the sensor picking up vibration, while a small peltier chip relayed temperatures to me. They where able to distinguish hot soup vs cold soup among other things but they didn’t find these tactors useful.
After coming to the conclusion that the tactors worked, but were distracting and actually took away from the experience of using a prosthetic hand, they moved in a new direction. They found through the experiments that fingers liked contact detection for fragile grasping. They then developed a new sensor that distilled down the features of the BioTac, called the NumaTac. An air filled open celled foam, the sensor can detect changes in pressure signaling a contact event.
Three of these sensors have been customized into the fingers of a prosthetic hand and can signal the hand that an object has been grabbed. This allows the hand to move quickly and responsively while empty, but slow down the fingers once an object has been grasped to enable low contact forces. This allows a prosthetic user to consistently pick delicate objects like eggs, consistently and reliably.
The idea that the hand has some local intelligence guiding its interactions may seem odd, but keep in mind that your hands do thousands of adjustments every second you perform tasks with them, all without you consciously thinking about each movement. It takes humans years to learn to do tasks seamlessly, but once we do the mechanics of pouring a glass of water, using a fork and knife, playing an instrument, typing, and, picking up eggs, all become reflexive, and possible to do using the sense of touch alone.
The information the sense of touch acquires is used in reflexive and automatic ways, that the brain expects to be present. Most prosthetic hands remove these reflexes, and require that amputees use their full attention to perform these simple tasks, which is frustrating! The simplified sensor and the reflex Vikram mentions allows users to do these tasks without requiring as much attention, just like you expect to be able to do.
Their sensors are 4 years away from becoming commercially available. They are working with the Department of Defense and the Veterans Administration to integrate Their technology into prosthetic devices.
Source: Wired
