Research On The Adaptive Processing Technology In Complex Condition

In the NC machining process, complicated physical factors, such as cutting force, influence the machining quality, efficiency and safety. At present, the ordinary NC technology focuses on geometrical motion control only without considering the effect of physical factors. Although adaptive processing technology could cope with the issue of the physical factors, there are still some unresolved problems, such as accurate on-line measurement of cutting load, process control strategy, as well as the realization methods of adptive control. In this dissertation, research on adaptive processing technology in the NC machine tool has been conducted deeply. The main work and contributions are as follows:Firstly, the model of spindle system and servo feed system have been proposed. It can forecast the variation of drive current under the different given loads. Experiment results show that the above response characteristics are of significance to the indirect accurate measuring of cutting load.Secondly, based on milling mechanism, the forecasting models of cutting force and torque have been established under different cutting parameters. The cutting experimental platform has been built. The influence of cutting parameter on cutting force was analyzed experimentally. It can be found that reasonable cutting parameters were very important for adaptive control of process.Thirdly, a new economic fast calibrating method of the relationship between cutting force and feed current has been put forward, by which a set of hydraulic device was employed to simulate the cutting resistance. The value of the simulation cutting resistance can be controlled by adjusting the hydraulic system parameters. Based on the method mentioned above, the calibrating equipment is developed, and corresponding BP neural network is formulated. The experiment results validate the mechanism of calibrating equipment. The calibrating equipment can act as dynamometer without the calibrating cutting experiments. Furthermore, an indirect measurement model based on motor current has been established considering the relationship between the cutting force and torque. This model has improved the measurement accuracy and is an effective on-line measurement method of cutting load in the adaptive control of cutting progress.Fourthly, based on fuzzy control theory, two-dimensional fuzzy controller used in the adaptive control of process has been designed, which applies the strategy of the combinations of rough and precision control, and the forecasting and fuzzy control are applied. The control strategy can raise the stability of the adaptive control progress and better fulfill the request of the cutting process.Fifthly, the hardware platform based on PC 104 has been set up, and the real-time adaptive control software system has been developed. The adaptive control plug-equipment has been developed through integration of the two parts above. The equipment is connected to management server based on Ethernet, and the adaptive control network system is built. The centralized monitor of NC machine tools has been realized. The plug-equipment has been adopted in five-axis machine tools satisfactorily.Finally, the integrated method of NC system and adaptive processing technology is investigated. The integration of NC system and adaptive control is realized through secondary development, which makes use of PLC of NC system. The adaptive module of open CNC system is develped, which has undertaken the function of the 7-axis NC system. The case study on the procession of propeller blades has been conducted, and its application results are remarkable.