The pressure sensor has entered the medical field a long time ago, and it has different functions in combination with various medical instruments, which provides convenience for the development of the medical industry, such as pressure sensors for sterilizers. As the technology is updated, the pressure sensor will play a more important role. Boyi Pneumatic, as a professional sensor production expert, has never stopped research on technology. Thin-film pressure sensors are used in many medical fields. When applied to the research of artificial limbs, they create miracles. Let us look at a research example.
How does it feel to lose a hand? I am afraid that ordinary people cannot answer this question. Some people with this experience have said that they will still feel the existence of "phantom limbs" after losing their hands, but in fact their prosthetic limbs are not tactile, and medical research has never stopped, through membrane pressure With the combination of sensors and medical treatment, reviving prosthetics is no longer a dream.
There is such a group of scientists, what they do is to make the prosthesis “tactile”. A research project conducted by the U.S. Department of Defense Advanced Research Projects Agency (darpa) called "Arm Proprioception and Tactile Interface" (HAPtiX) aims to allow prosthetic wearers to use prosthetic limbs with thin-film pressure sensors with wireless transmission capabilities With a real feedback function, the prosthesis becomes a real part of the patient's body.
Spetic, a volunteer from the Cleveland Veterans Medical Center, is a person who needs a prosthesis. He lost his right hand in a factory accident, but fortunately, as a volunteer of the experimental project, he received the finger tactile neural interface transplant. For amputees, the functional role of the prosthesis is greater than that of the limb. The ordinary prosthesis cannot feel any sense. For the user, it is more like a "tool".
The researchers designed an experiment. They let Spetic grab the cherry and pull out the stem of the cherry, but the cherry was broken in his hand. Next, the researchers implanted a thin film pressure sensor in the thumb and middle finger of the prosthesis. This time Spetic The cherry stem was gently grasped and pulled out without damaging the cherry at all. After a large number of repeated experiments, the researchers obtained data that the success rate was only 43% when the membrane pressure sensor was turned off, and the success rate was as high as 93% when it was turned on. Spetic himself also said that it felt like he was grabbing cherries with his own hands, which greatly encouraged the development of "tactile prostheses".
Although it sounds like "implantation" is very simple, but the actual operation requires some sacrifices by volunteers. He needs to undergo a surgical operation. The arm is connected to an artificial neuron electrode, which is equipped with an electrical signal sensor. After implanting it into the remaining nerve of the human arm, it acts as a microelectronic device connecting the human nervous system and the prosthesis. "Interface" role.
Spetic's forearm is implanted with electrodes, and the upper arm has a wire connected to the computer
In the initial experiment, there were 20 contacts on the prosthesis, which were connected to 3 nerves. Stimulating different nerves will produce different feelings. When grasping objects, through complex computer calculations, the neuron electrodes will pulse the electrical pressure. The signals are converted into nerve impulse signals that the human nervous system can recognize, so when the amputee touches the real object, they can perceive the "real touch and power" of the object.
In 2014, researchers implanted 3 electrode interfaces in Spetic's forearm, and then up to 8 can be reached. When the next generation is developed, it may reach 4 times the current. The more electrode interfaces, the more likely it is for the person wearing the prosthesis to regain a more detailed feeling.
Electrode interface
Although when the membrane pressure sensor started to work, Spetic felt tingling due to the current, in order to improve the situation and provide a more natural feeling, the researchers tried to change the timing and pulse of the electrical pulse. The sequence is constantly adjusted according to his feelings, and finally they found that in a one-second electric pulse cycle, first increase and then decrease the intensity of the pulse, you can change the tingling sensation into a more natural "pressure of the object pressing the finger ". Spetic described this pressure as "like putting my finger on my neck to feel the pressure of the pulse".
So far, Spetic has been able to feel the weak roughness of velcro and sandpaper, as well as the feeling of moving objects floating and flapping his "hands", even if he wears an eye mask and does not rely on vision, he can Control the movement and strength of your prosthesis.
In the future, researchers hope to be able to make an independent micro-processor that does not need to rely on an external computer and can be implanted between the prosthesis and the "interface" to provide power for the "tactile system" without daily external power. In this way, a person wearing a prosthetic limb will have a natural "mechanical arm", and with the development of technology, it can also be infinitely close to the real human arm.
When this technology succeeds, it is not just people who need to wear prostheses. We may be able to make a bold idea of using pressure sensors in combination with medical technology. The limbs can be replaced by machinery. The internal organs can also be replaced by machinery under technical conditions. As long as the brain does not die, can humans obtain eternal life by this means? I don't know how long it will take scientists to solve this puzzle.