Carnegie Mellon developed a retractable optical sensor

Sensor is one of the essential parts of the machine, which has led to the development of many machines. Recently, a retractable optical sensor was developed at Carnegie Mellon to take the robot to the next level of flexibility. Researchers at Carnegie Mellon University have developed a three-finger soft robot hand with multiple 3D printed fiber optic sensors and a new retractable optical sensor. The soft robot can detect less than one tenth of a Newton's force. The project received NASA support. Using optical fiber, the research team placed 14 tension sensors inside each robot's finger, which were modeled after the human finger's skeletal structure. The fingertips and two "phalanges" of each finger are 3D-printed, and the "phalanges" are articulated and the joints are covered with a silicone rubber "skin." This technique provides the robot finger with the ability to determine the location of its fingertip contact and detect the insignificant amount of force it is subjected to. Although the latest scalable optical sensing materials are not used in the current version of the robot, researchers hope it will be used later in the skin of soft robots for greater feedback. Objectively speaking, currently used pressure or force sensors are problematic. This is because the wiring is too complicated, the sensor is easy to break. And they are extremely susceptible to interference from electric motors and other electromagnetic devices. The use of fiber optic sensors do not have these problems, and even a single fiber can contain several sensors. In this project, all the sensors on their robot's finger are connected to 4 fibers and they are completely immune to electromagnetic interference. The researchers said they are developing the technology to improve robot autonomy. "If you want robots to work autonomously and safely respond to unexpected forces in everyday environments, it will be necessary to equip robots with more sensors than is currently commonplace." Carnegie Mellon University Robots Associate Professor Yong-LaePark said: "There are thousands of tactile sensory units in a person's fingertip skin, and hundreds of mechanical stimuli receptors on each leg of a spider, while in the most advanced form Robots - such as NASA's Robonaut - have only 42 sensors on their wrists and wrists. " The robotic hand developed by Park was aided by the school's mechanical engineering students LeoJiang and KevinLow. The device integrates a fiber optic Bragg grating (FBG) sensor currently on the market that detects tension by measuring the wavelength shift of the emitted light within the fiber. The fingers are bent by an active tendon, while straining the fingers by the opposing force provided by the other passive tendon. The new retractable optical sensor is a sensor that the development team hopes will be available on the next version of the robot. Because of the lack of elasticity of conventional optical sensors, it is well known that glass fibers are almost inextensible and that even optical fibers made from polymers have a stretch factor of only 20% to 25%, which is of limited value. However, by combining silicone rubber with a reflective gold, the researchers found that when pressure was applied to the sensor, light could escape, allowing them to measure the force accordingly. Park believes that this type of sensor can sense the contact and measure the amount of force.