| With high-speed development, the technique economy has more and more request to the machine manufacture. Especially the fast growing of calculator technology promotes the mechanic technology making progress powerfully. At present machine manufacture has broken 0.01 μm with feed technique and roundness machine. It's even arrived to nanoscale in coarseness making. See from the history of the development of the industry, exaltation of the machine manufacture is closely-related with continuous improving of measure technical. The nano fabrication technology puts forward the higher request to the product measure technology by all means. The existing instrument measuring accuracy has already couldn't satisfy the need of manufacture industry. The product accuracy extending lengthways also will bring large impact to the local instrument manufacture industry. It will even extrude them from the market which will push them enlarging the investigation and keeping up with advanced technique in the world aggressively. And it will promotes the measure technology to nanoscale which match the nano fabrication technology mutually. In recent years, the error check and measure problem of large size shaft parts, especially for shape errors, is increasingly standing out. For example, the train speed pre hour is improved for saving time and relaxing traffic jam, the entire train vibration, wear and tear causing by manufacture error become more and more serious, that problem is needed to solve urgently. Another example, the main shaft length of common used fan type pulverizing mill on generating equipment is 2795mm,maximal shaft diameter is 440mm, the axiality error of below 0.02mm between bearing axial diameter and gear for grinding coal installment diameter is required. At present the assessment is carried out only by taper socket gage and checker's experiment. It inevitably results to disqualification parts being assembled. Thus the enterprise credit standing is impaired greatly. The car main shaft of Changchun passenger car and saloon car main shaft of Changchun first mobile factory and so on all belong to large size shaft parts. In order to ensure the quality, more reliable and accuracy equipment is certainly needed. According to above-mentioned circumstance, the paper carried on the research to the intelligent instrument used for measurement of large size shaft parts which was initially developed. After I mastered the structure and principles the system and analyzed original shortage of the system, I improve its'hardware and software systems, perfecting the measure system. Its'main contents are as follows: 1. Confirm the instrument system scheme The paper analyses the characteristics of large size shaft parts which are big and heavy and considers the feasibility of measuring, it takes below control schemes to satisfy the accuracy and quickly respond requests: It adopts open loop control with step-motor and retarding mechanism to control the axis moving and close loop control with photoelectric code device and displacement grating sensor to measure the principal axis turn angle and the radius. It develops the measure and control system with Celeron466 as measuring host, Windows as operation system and Visual C++6.0 as develop tool and go together with photoelectric code device, displacement grating sensor and inductance displacement sensor. The whole measure process adopts the PC to control the related data processing, result displaying, keeping and printing. It combines the machine technique, optical technique and the electronics techniques to complete the parts sampling and the control of instrument together. It really carried out the intelligence of instrument. 2. Design interface It self-makes the ISA expand I/O card, the independent A/D card which carried out the digital data collection of photoelectric code device and displacement grating sensor and the analog data conversion of inductance displacement sensor. the numeral measure of collect and give or get an electric shock the feeling to move to spread the feeling machine to imitate the quantity of conversion. It helps gaining the instrument request measure accuracy and resolution and obtaining human-computer interaction automatization and intelligence. 3. Assess errors It compares each error assess method and chooses the minimum zone method to build mathematics model and calculate the roundness, concentricity, cylindricity. It solves the range function's and the maximum function's minimization problem with spendley method. It also compares the results of the minimum zone method and the least squares method and confirms the least squares method is the best method to calculate the roundness, concentricity, cylindricity. 4. Error compensation It adopts two points turning separation method to solve determining the measurement baseline problem and compensate the error caused by measure head's motion error. It analyzed the influence that measuring line did not pass rotational center and solved it with shovel shape measure head. It analyzed contour transform caused by tilt of cylinder which reduces the instrument system accuracy and solved it by count the tilt angle of whole axis and use it in compensate function. Using above error compensation methods, the instrument system can gain the ideal measuring accuracy in the lower hardware. Thus it can obtain purpose of cost saving. 5. Judgment of retrievability Study the arithmetic of retrievability judgment of the unqualified parts and develop the corresponding software. It will lower the repairing cost of the unqualified parts. After careful theories analysis and experiment researches, it was approved that the instrument this paper studied matched the design requests and the function targets. The instrument system has been designed with fitted measuring scheme, reasonable structure and advanced technology. Each kind of component used in the instrument was suited its'operation. The instrument not only can carry on several inspects of index sign to the shaft parts, but also measure the large size parts whose max diameter is 450 and max length is 3000mm and max weight 1200kg. The...
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