Research On Tactile Sensing Technology Based On 3D Deformation Of Elastic Body

In recent years, with the increase in labor costs, more manufacturers have adopted automated production lines and more robots have appeared.Robots also require a variety of different perceptual skills. Among them, the tactile sensor is essential. And robots rely on tactile sensors to perceive the outside world. When complex objects are manufactured by robots, the tactile sensor is particularly important. In addition to industrial applications, tactile sensors have a wide range of applications in the medicine, in the military, and other services.Tactile sensor could measure the magnitude of the force, direction and distribution. Also, sensors should be small and be of high resolution. At present, tactile sensors could be divided into two categories. The first category is a pressure sensing unit to measure the force. Force vector can be detected by a single point. It also could be composed of multi-point array of sensors, such as the composition of a plurality of strain gages sensor array. The second category used the elastomeric member as a contact sensor. When the elastomer was deformed by the force, deformation and shape of the elastomer could be detected to calculate the magnitude and distribution of the contact force. Soft elastomer ensured to fully contact with the target object, and the peripheral circuit was relatively simple. So this paper adopted the second category.The sensor consisted of the elastomer, collecting systems of three-dimensional deformation and the lights. The basic idea was to detect the deformation of the elastic body after analyzing the three-dimensional deformation and establishing the relationship with the contact force. In this paper, two kinds of schemes were used to detect 3D deformation. The first one was the grating projection, which used the Fourier transform and the phase unwrapping to reconstruct the 3D deformation. The second one used binocular vision to reconstruct the 3D deformation of the elastic body after the image acquisition, camera calibration and mark recognition.In the finite element analysis software, the elastic body was applied in the simulation analysis. Normal extrusion and lateral extrusion were made by finite element method. After setting parameters in the Ansys, two kind of the contact were measured and data was recorded. In the data analysis, it was found that normal extrusion of little displacement matched the theory model very well. The direction of lateral extrusion force was obtained by using the normal vector of the deformed part. And the magnitude of the force was calculated by the finite element method. The possible error in the whole sensor were analyzed, which provided a basis for improving the accuracy of the sensor. At the end, the achievements and innovations were summarized. And the deficiency of the current research and the direction of future research were pointed out.