3D vision technology and its application of the ho

3D vision technology and its application of industrial robots

industry, as an important support for China's industrial development, is now more and more widely used in the fields of manufacturing and logistics. As the "eye" of industrial robots, 3D vision has become a key factor affecting the application and performance of industrial robots. How to improve the accuracy, speed and reliability of industrial robots through 3D vision control technology has become the focus of attention at home and abroad. In this paper, the author will introduce the 3D vision technology and its application of industrial robots through the search of relevant patent documents at home and abroad

distribution of 3D technology abroad

through the search of patent documents published as of February 2, 2018 through the dewant world patent database and the world patent digest database, it is found that since the patent application with publication number of USA "visual motion tracking system" submitted by General Motors in 1979, the total number of patent applications involving 3D visual control technology of industrial robots in the world is 2774. Among them, the commonly used types of this technology are: passive 3D vision technology (divided into monocular 3D, binocular 3D and polycular 3D, which are stereoscopic vision systems composed of one, two or more cameras respectively), laser 3D scanning technology that realizes stereoscopic measurement by capturing the projected laser image by camera, structured light 3D scanning technology that realizes the process of 3D angle reconstruction by using projector through structured light coding technology, and high-frequency optical signal emission through LED, And TOF camera technology that realizes distance measurement according to the time difference between signal transmission and return. Monocular 3D vision technology has simple structure but low accuracy; While binocular and multi camera 3D vision technology has high accuracy, but the algorithm and structure are relatively complex; Laser 3D technology is fast, but it is difficult to achieve high accuracy due to the limitation of laser speckle defects. At the same time, structured light 3D technology has high precision and speed, but it can not be used on transparent, black or strongly reflective surfaces. TOF camera technology has high speed and precision, but the cost is relatively high. At present, the development of passive 3D, laser 3D and structured light 3D vision technology is relatively mature and widely used

accuracy is an important indicator to measure the visual performance of industrial robots. At present, many basic technologies and core patents to improve visual accuracy are in the hands of some large enterprises in Japan and the United States, such as FANUC in Japan and konasi in the United States

FANUC's main products in this field are industrial robots configured on industrial sites. The systems used include stereo vision, structured light and laser scanning. Its representative 3D vision system technology is a patent application with Publication No. usb1, which stores a square box template with ID parameters and lens determination position information. It converts the deformed image in the stored information into a real image, determines the parameters of the real image and compares them with the template parameters, so that the computer can recognize the square box used for the robot's early operation. In addition, the patent application with publication number epa1 also relates to the calibration system of the center point of the tool. On this basis, fanucirvision 3DL vision system was also developed by fanucirvision in 2006. The vision system uses a 3D laser installed on the ground to complete the visual data acquisition. This technology solves the problems such as the position change of the feeding positioning hole after the robot grabs the blank, and can automatically complete the position change to achieve high-precision feeding

Cognex mainly focuses on improving the accuracy of the system through image processing. For example, patmax, which he owns, also proposed the technology as an object positioning technology with high accuracy, high speed and high processing quantity in machine vision, which was first patented in the world in 1997. Since then, a series of patent documents, such as the patent application with publication number usb1 "rapid and high-precision multi-dimensional map, China's plastic sealing machine has obtained a considerable development of positioning" The patent application with publication number usb1 "fast and high-precision multi-dimensional graphics detection" and the patent application with publication number usb1 "fast and high-precision multi-dimensional graphics detection" all involve patmax technology. This technology uses a series of boundary curves that do not depend on the pixel lattice to obtain the geometry of the object, and then looks for similar images in the image. The most remarkable feature of this technology is that it is not limited by specific gray levels. In addition, from 2006 to 2008, the company also submitted a patent application with publication number USA1 "methods and equipment for practical 3D vision system", a patent application with publication number USA1 "systems and methods for positioning 3D objects through machine vision", and a patent application with publication number USA1 "systems and methods for 3D calibration of objects using machine vision". At the same time, the company launched visionpro3d software system based on these patents in May, 2011, which can provide accurate and real-time positioning 3D position information, and can also be applied to loading and unloading, packaging and assembly verification in precision manufacturing industries such as automobiles

in addition to improving the technical accuracy, safety is also a very important indicator in the application of industrial robots. Sik company in Germany is a company that improves the safety of industrial robots through 3D vision technology. For example, in the patent application with publication number epa2 submitted by the company, nearly all the control systems of experimental machines need to solve the problem of changing the mathematical model of the system caused by the diversity of test pieces, so the structured light 3D image technology is adopted. When the robot and the operator coexist in a certain area, the 3D sensor is used to determine the action trajectory of the operator, avoid safety accidents, and then provide intelligent guarantee

3d technology domestic patent layout

the author searched the Chinese patent digest database and found that as of February 2, 2018, domestic applicants had submitted a total of 594 patent applications in the field of 3D vision of industrial robots, mostly involving the application of 3D vision in industrial robots, and about one third of them were applied for by universities and scientific research institutes. Some domestic enterprises focusing on the research and development of industrial robots have launched a patent layout, such as Shenyang Xinsong robot Co., Ltd., which has submitted a total of more than a dozen patent applications in this field, and most of them have been submitted in the past five years. For example, in the patent application with publication number cna, its vision based on color stripe structured light guides the movement of the robot arm, which can make the operation mode of the robot arm more accurate, This technology realizes the optimization of robot action speed and accuracy. In the patent application with publication number cna, it adopts the image matching method combining heritage algorithm and Hausdorff distance to find the camera to obtain the position information of the measured object in the image, then the mobile robot irradiates the laser on the measured object, reads the laser information in the camera image, and then uses the principle of triangulation to measure the three-dimensional information of the object. From the above technologies, we can see the efforts made by Chinese industrial robot enterprises in 3D vision technology, especially in the direction of 3D technology application to technological innovation. At the same time, in recent years, domestic enterprises have made innovations in more mature fields such as laser 3D and structured light 3D technology. In addition, they have also made improvements in TOF technology, which requires less clamping of special materials in patent applications. For example, the patent application of "a method to improve the ranging accuracy of TOF phase ranging radar" with publication number cna can improve the ranging accuracy without changing the hardware technology

to sum up, the 3D vision control technology applied in the field of industrial robots has gradually matured. Many important technologies come from Japan, the United States, Europe and other countries and regions. For example, FANUC Corporation of Japan has integrated 3D vision products into its own products as additional equipment. American visual technology enterprises such as connexion pay more attention to visual technology itself, while European visual technology enterprises focus more on the application of a certain field. At present, the 3D vision control technology in our country mostly involves the theoretical research and specific product application in Colleges and universities, and gradually begins to work towards the direction of visual technology products that can be developed and produced. Chinese industrial robot enterprises can catch up with and develop products with independent intellectual property rights in a specific application field, so that industrial robots have a pair of "golden eyes"