The PSD Real-time Detection System Design And Error Analysis For Giant Extruder Moving Part’s Coaxial

After giant extruder run for a long time, the gap between moving parts and guide increased, while the moving parts and the center line of squeeze do not coincide, having impact on the geometric accuracy of products, thereby resulting in enormous eccentric load on the body of extruder, which would shorten life of the extruder and even devastate the extruder body, followed by a production accident. Now, there are some disadvantages in the extruder moving part’s center detecting system that is in low precision, poor real-time and can not comprehensive evaluate active motion precision of moving parts, which is difficult to meet the testing requirements.In this paper, the200MN giant extruder was selected as the research object. Analyzed the advantages and disadvantages of the common optical detection system, and then a real-time detect extruder coaxality system including software and hardware was proposed based on PSD (position sensor detector). In order to reflect the kinematic accuracy of moving parts comprehensively and objectively, coaxality was presented as a evaluation parametric. In addition, a data transmission method combined simultaneous acquisition and data package was proposed, which the number of data transmission was reduced into a quarter of the number of regular communication mode, while the time interval of detection data in different monitoring point of an active part was shorten, minished the mathematical model error and improve the real-time of the system. Lens image method can overcome the disadvantage of narrow PSD detection range. Making use of optical band-pass filter to sift the optical line absorbed by photo-surface, lower the error of environment lighting to offset detection unit under the resolving capability. The PSD non-linear correction method commonly used basic principles of performance proposed an improved dual-time interpolation algorithm to improve the detection accuracy of the system. According to the theory of geometrical optics, mathematical model was established, system error function relationship of the independent variable formula was derived, which provides a theoretical basis for the variable value system error compensation and effectively improve the detection accuracy of the system.Research and experimental results indicated that the detection range of whole system is109mmX109mm, and the detection accuracy is0.16mm.The frequency of single moving part is4HZ, which can realize the real-time environmental online monitoring of active parts motion accuracy effectively.