Papers by Author: Xi Chen Yang

Abstract: FANUC industrial robots are used more and more widely. However, robots’ communicant protocol and interface are different and unopened. Robot interface technology has become an important factor. Controlling robot movement via interfere has become an important issue in recent years.NI LabVIEW has powerful data acquisition and measurement ability and friendly graphics programming interface. It has the most percentages in the field of automatic measurement. The interface between PC and FANUC industrial robot is studied. A serial of sub VI are developed based on LabVIEW, including connecting robot with PC, initializing robot interface, reading and changing system variables, reading and changing position variables, displaying current position, controlling robot programs and so on. This paper describes the hardware and software components of the system, and the typical communicant and control module between PC and FANUC robot developed by LabVIEW. After testing, the function of every module can be achieved and performs well.

Abstract: Process planning strategies for surface hardening by laser robot was introduced. It has many characteristics, such as integration, flexibility and environmental protection. According to technology requirement, the path planning and robotic hardening program were accomplished automatically. The FANUC ROBOGUIDE was used to realize simulation. Experiments were carried out to evaluate the application of process planning strategies for laser surface hardening.

Abstract: Special software for laser molten pool temperature field based on LabVIEW was developed．Thermal radiation image of laser molten pool temperature taken by CCD were processed by the special software. It was shown that the software had a visual interface and the laser molten pool temperature field could be measured at real-time and the whole system is simple and efficiency. The software is easy to operate and can measure the laser molten pool temperature field quickly and exactly.

Abstract: The powder feeder head is studied, which is one of the key to laser cladding. In view of many coaxial nozzles that are used nowadays, we have found that while cladding is doing, most of the nozzles have poor affect on powder-gathering. So as have researched on the theoretical and experiments, we designed a new coaxial nozzle, which has a great affect on powder-gathering, and can be modular disassembled. We have researched on powder stream theoretically, shot the morphology of powder stream by using high-resolution CCD camera, and analyzed the parameters of powder stream. And this new coaxial nozzle has been used in laser cladding experiments.

Abstract: As an advanced repair technology, the laser remanufacturing technology has been paid much more attentions recently. The authors previously studied the vision calibration by using the Matlab Calibration toolbox. Since the boundaries of a single image have to be specified manually, however, the Matlab toolbox based calibration method will be time consuming and low precision. This article continues the study of vision calibration for laser remanufacturing machine system and proposes a new binocular vision calibration method based on Halcon10.0 software. Experimental results show that the proposed calibration process consumes shorter time and is able to achieve higher precision.

Abstract: 3D surface reconstruction has been widely used in reverse engineering, remanufacturing and automatic measurement. Binocular stereo imaging technology is the main method to obtain 3D information. Images are acquired from different positions of the object. The 3D coordinates of the point can be calculated according to the point’s coordinates in left and right cameras. The key to ensure the accuracy of 3D reconstruction is high precision and fast matching method of two images. As the image feature was not obvious, structured light is used. For its easy identification and extraction, the method has been more and more widely used. But the former research cannot ensure the matching exactness or matching algorithm takes too much time. In order to improve the precision and efficiency of 3D measurement, a fast and simple structured light matching method is designed based on epipolar geometry. This method can ensure 100% matching accuracy. It does not need other assistant tool except for structured light projector. On the beginning of the measurement, structured light is projected onto the object to be measured. Two images of the object with structured light are captured by two cameras in different positions. Structured lights extracted from the two images are matched by the new algorithm. The 3D coordinate of this structured light is calculated. The position of structured light is changed on the object till completed. From a lot of experiments, the proposed grating matching method is proved and it is a technique with high precision, low costs, easy operation, and an automatically matching method. Furthermore, it can be widely used in most of 3D reconstruction system.

Abstract: In this paper, the theory of the powder temperature measurement using radiation is briefly illustrated, and the measurement system on temperature field in coaxial powder stream of laser cladding by applying color CCD and digital image processing technology is designed. The experimental result indicates that this measurement system can test the distribution of temperature field.

Abstract: In this paper, a measurement system of temperature field in laser molten pool by CCD based on DSP is presented. The paper also presents the system of hardware, software process, and the method of image processing by DSP. To solve the real time problem in the processing of measuring the temperature field, the system uses DSP as the main CPU, processing the image without a computer. By this method, the system can become simple and efficient and measure the laser molten pool temperature field quickly and exactly. Gradient image of temperature field is displayed on LCD after real time processing by this system. The final picture of temperature field can be directly analyzed.

Abstract: Laser direct manufacturing and re-fabricating have been used in many important fields in recent years. However, simulation and measurement of velocity fields in carrying gas and powder particles are still a challenge. In this paper finite difference method has been selected to simulate the velocity fields of powder/gas fluid. A novel DPIV system has been developed to measure the velocity fields. The DPIV system mainly consists of Nd+:YAG laser and CCD camera. Comparing the result of DPIV measuring with computer simulating, a good agreement can be obtained. After further developing, DPIV will become a useful device for laser manufacturing.

Abstract: Theoretical models of temperature field are presented from Beer-Lambert law. This paper uses Beer-Lambert law to calculate powder flow on the absorption of energy and applies the law of the conservation of the energy to calculate the temperature of powder stream. This paper analyzes the effect of the various factors on the temperature field of powder flow. Temperature field of powder stream is measured by CCD camera. Finally the comparison of the theoretical results and the experimental results indicates the accuracy of the theoretical calculation.