Zhen Yun Duan

A Calibration Method for High Precision Vision Measurement System

In order to realize precision measurement for the computer vision measurement system, a system comprehensive calibration method based on straight line imaging characteristics is proposed. The method uses parallel straight line edges of general 00 level gauge groups to comprehensively calibrate the measurement system. It establishes the calibration function that describes the corresponding relationship between the imaging point location and space point position, and then determines the coefficient of the calibration function according to the linear characteristic of gauge block measurement surface edges imaging. This method is simple to operate and is easy to realize and has good versatility. It can comprehensively correct all kinds of system errors such as the optical distortion, the perspective error, the sensor position error and location error of edge detection algorithm. Repeated measurement experiments for the gauges show that the precision of the measurement system can reach by means of this calibration method.

Strength and Mode Analysis of Testing Machine of 3MW Wind Turbine Bearing with Finite Element Method

Wind turbine always run in complex environment, as the key components of wind turbine, it is extremely important to test wind turbine bearings properties, so we need develop a testing machine to test their properties. The static strength and dynamic properties of testing machine key components of 3MW wind turbine bearing were analyzed with the finite element software ANSYS to obtain the strength and stiffness check as well as the optimizing design of testing machine key components of wind turbine bearing. The strength was checked and satisfied with the demand of material strength. The former five orders natural frequencies and corresponding modes were obtained, which provides scientific basis for future design．

Research on Nonlinear Modeling and Simulation for Flexible Drive Train of Wind Turbine

Wind energy has preferable economic and social benefits because of its cleanliness and free pollution, short construction period, and so on. The wind turbine is a complicated nonlinear uncertain system. So the modeling and analysis of system is crucial to the system design of wind turbines. Drive train performance of wind turbine was analyzed, and modeling methods were presented according to rigid drive train and flexible drive train. Based on those models, software has been designed to show the performance of the wind turbine, and then contrast with the result that simulated by GH Bladed software, to verify the accuracy of the models. The results show that the models can be used in optimum design and control strategy.

Study on CCD Measurement System Based on Image Processing

The measurement system based on industry CCD and image processing was established to measure 2D sizes of parts. The CCD sensors, lenses, illumination and image acquisition modes were chosen to establish hardware part, according to the requirement of views and precision. The software system was developed to extract the edge of the part from the digital image and transform it to a polynomial. The actual sizes of the part were measured with relative comparison calibrating method. Tests and analyses show that it is an untouched, automatic 2D Measurement system with high accuracy.

General Structure Configuration and Parametric Design Method of Wind Turbine Tower

In order to improve the design efficiency of wind turbine tower, a design method which combines configuration and parametric design is proposed, the general structure model of wind turbine tower is given, and the parameter relation model of tower components is established. Based on skeleton and coordinate system coincident method, the automatic assembly of 3D tower model is realized. An automated 3D design software system of wind turbine tower is built by the API of Pro/E. The validity of the system is proved by wind turbine SUT-1500.

Tool Path Calculation Based on the Actual Tool Profile

Due to tool wear and making errors, calculating the tool path based on the tool theory model has a great deal of influence on the accuracy of surface finishing machining. In order to solve the above problem, a photogrammetry method is used to extract the rotary cutter profile, and then the tool surface is get by letting the fitting profile curve revolves about the cutter axis, finally the cutter contact path is obtained based on the minimal orientation-distance algorithm. Experiments prove the cutter contact path is just on the theory surface of the workpiece. Therefore the accuracy of surface finishing machining will be greatly improved by the method.

Research on On-line Detection and Data Processing Technology of Welding Seam for Bellow

In order to improve the welding quality and welding speed of irregular bellows, according to the characteristic of welding seam of bellows, an automatic and on-line detection technology is proposed in welding technique. The infrared laser sensor is used for measuring with non-contact and real-time detection of welded joint center, the position of welding seam is transfered by the IEEE-1394(Fire Wire). After data preprocessing, the coordinates of feature point are extracted, be storaged and forecasted, then sent to the control system, the moving of welding gun is controlled along track scanning. According to the accuracy analysis of on-line detection system of bellows, the technology of tracking measurement is stable and reliable, and it is effective for improving measuring accuracy and efficiency.

Study on Machining and Measurement for Borosilicate Glass Conical Ellipsoid

Surfaces formed by rotating quadratic curve are widely applied in engineering practice. After having studied machining methods and machines, the CNC grinding method based on macro program B for borosilicate glass elliptical cone surface machine with high precision is proposed. Within the allowable error, the coordinates are calculated according to the equation of axial section curve and the surface is formed with tools moving on axial section curve. Through setting parameters of the lathe, the new canned cycle can be defined to process all different kinds of the elliptical cone surface of same type. With surface triangle adaptive measurement method, machined elliptical cone surface can be detected on coordinate-measuring machine and compared with the theoretical curve. The tolerance resulted from analysis is within 0.025mm. Except ellipsoidal surface all solids of rotation and their deformation, in which their axial sections are represented with equation, can be processed and measured with this method.

On-Line Detection and Tracking Welding Control Technology of Thin-Walled Bellow

In order to improve the welding speed, quality and automation level of thin-walled bellow, on-line detection and tracking welding control technology is proposed which includes on-line detection system and tracking welding control system. Based on laser sensor, on-line detection system can rapidly filter the data, and the data is stored in a queue, the control system which is based on motion control card is developed by using ActiveX controls for programming, VB is used to develop the integrated user operating system, other control tasks are completely integrated on this system to realize real-time welding control bellow. Results showed that the system is reliable and effectively, the automation level of the bellow welding is greatly improved.

Study on On-Machine Measurement of Rotating Tools Based on Image Processing

It is necessary to develop an on-machine measurement system of cutting tools with high precision and high efficiency on the NC machining, so that it can decrease non-production time and improve machining efficiency. A system for high precision measurement of rotating tools on the basis of image processing is described in this paper. Images are acquired from a digital camera and transmitted into a computer. The working profile of rotating tools and geometrical parameters are extracted accurately through image processing technology. Depending on theoretical analysis and experiments, this system can be widely applied to tool offset and NC programming based on working profile of the tools.