Researh On Synchronous Control Of Scanning Movement For Industrial CT

As a kind of modern digital radiography systems, industrial CT(Computed Tomography) is widely applied in the manufacturing. With the development of technology, it is a trend to call for higher imaging speed and accuracy for industrial CT. So it becomes a hot and difficult research to improve the accuracy of the scanning movement and its synchronization. The purpose of this paper is to improve the accuracy mentioned above.Firstly, the requirements of movement control for industrial CT are analyzed in this paper, and then the model of the control object- Permanent Magnet Synchronous Motor (PMSM) is presented. Secondly, the control principles are expatiated in details, and a position servo system is built based on the PMSM model. On this basis, the model of PMSM position servo system and executing agency are built respectively. Moreover, the factors which would affect the performance of the model are analyzed.Based on analyzing the characteristic, such as principle, controller construction, advantages and disadvantages, of PID and fuzzy control strategy, the two kinds of control strategies are combined, namely, fuzzy control strategy is applied to tune the parameters of the PID controller online. Subsequently, the integration separation PID algorithm, universe self-tunning fuzzy algorithm and fuzzy parameter self- tunning PID algorithm are applied respectively to design and simulate the position loop of the system. The results show that the integration separation PID algorithm responded fastly, but its anti-interference ability is worse than the universe self-tuning fuzzy algorithm. Merely, there is error and jitter in the steady-state of the latter. However, the fuzzy parameter self-tunning PID algorithm has good anti-interference ability, and its overshoot is little.The problem that how to get higher synchronous control precision of multi-axis movement system is studied deeply based on discussing the controlling precision of single-axis movement system. Then, the structure of multi-axis synchronous controlling system applied presently is discussed. Subsequently, the principle and design method of adjacent cross-coupling control structure is discussed too. Next, the stability of the multi-axis synchronous control system utilized this construct is analyzed. In the end, the two-axis synchronous controlling system which utilized the parallel control structure, master-slave control structure and adjacent cross-coupling control structure respectively are modeled and simulated. The simulation results show that the adjacent cross-coupling control structure has higher synchronous controlling precision and better anti-interference ability.