How Do Robots Perceive The World?
Today, with the continuous development of sensor technology, many new sensors have been developed. Before,ETH researchers developed a novel and low-cost tactile sensor that can help the robotic arm to grasp sensitive and fragile objects.
Humans can pick up fragile or slippery objects with our hands. Our sense of touch allows us to feel whether we firmly grasp the object or whether the object will slide through the fingers, and then feedback to the palm of the arm, by adjusting the strength of the hand grip accordingly To grab the object.
Robot grabbing arms that are responsible for grabbing fragile, slippery, or complex surface objects also need this feedback.
Robotics researchers at ETH Zurich have now developed a tactile sensor that can come in handy in this situation and marks what they believe is an important step towards "robot skin."
The engineer pointed out that the extremely simple design of the sensor makes its production cost low. In essence, it consists of an elastic silicone "skin" with colored plastic beads and a conventional camera fixed on the bottom surface.
The sensor is based on vision, and when it comes in contact with an object, dents will appear on the robot's silicone skin. This changes the pattern of the bead, which is recorded by the fisheye lens on the underside of the sensor. According to these changes in the pattern, the force distribution on the sensor can be calculated,
In order to calculate which forces push the beads in which direction, the engineers used a comprehensive set of experimental data: in standardized tests through machine control, they checked various contacts with the sensor. They can precisely control and systematically change the location of contact, the distribution of force and the size of the contact object. With the help of machine learning, the researchers recorded thousands of contact instances and accurately matched them to changes in the magnetic bead pattern.
So far, the thinnest sensor prototype that researchers have built is 1.7 cm thick and covers a 5 x 5 cm measurement surface. However, researchers are using the same technology to achieve larger sensor surfaces equipped with multiple cameras, which can also identify objects with complex shapes. In addition, their goal is to make the sensor thinner-they believe that using existing technology can achieve a thickness of only 0.5 cm.
Since the elastic silicone is non-slip and the sensor can measure the shear force, it is very suitable for the robot to grasp the arm. When an object threatens to slide out of the arm's grip, the sensor will recognize it so that the robot can adjust its grip.
The combination of virtual and motion, this new type of sensor is an auxiliary tool for robots to perceive the world.