Research And Development Of On-Board Measurement System For Large Diesel Engine Cylinder Block

With the improvement of precision machining technology globally and as a need for high measurement precision,precision has become the mainstream direction of the manufacturing industry at present.The quality inspection results of components after machining have an important impact on the assembly of the whole product,and traditional measurement methods can no longer meet the strict precision requirements and hefty production tasks currently.On-machine measurement technology is widely used in the measurement of components in the manufacturing industry by virtue of its high measurement precision,high measurement stability,and possibility of machining compensation.Aiming at the problems of shape and position tolerance detection and measurement data management of a large component,this thesis studies the measurement path optimization of the component,and designs and develops an on-machine measurement data management system that can measure multiple geometric features.This thesis analyzes the composition of the on-machine measurement system and the measurement requirements of the enterprise,and proposes the overall plan of the on-machine measurement system.According to the measurement requirements,the measurement software is divided into software modules.Then researched the measurement path planning technology,introduced the polychromatic set theory,ant colony algorithm,and genetic algorithm through the analysis of the TSP problem and path optimization,and compared the two algorithms to verify that the genetic algorithm is effective for the model.The path optimization is more appropriate,the algorithm implementation is simpler,and the path is better.Collision check and avoidance are done for the optimal measurement path,and obstacle avoidance points are added to the path to prevent the probe from interfering with components or fixtures.Through the research on the principle of geometric measurement,combined with the module functions of the software,an on-machine measurement data management system has been developed,which realizes the functions of acquiring measurement coordinate files,calculating geometrical quantities,querying component information,and saving and modifying data.An on-machine measurement system was built,and the measurement experiment of diameter,cylindricity and perpendicularity was carried out on a large diesel cylinder body,and the standard specimens were used for test verification on a three-coordinate measuring machine,which verified the measurement precision of the system.Based on the Coburg Longmen Machining Center 6500AG,the overall system plan is determined from the two aspects of software and hardware,and the measurement path planning and geometric quantity measurement principles are studied.On this basis,an on-machine measurement system is developed,and the experiment has verified its measurement precision.The research results have important application value for improving the automation level of mechanical processing.