The Study On Quasi-adaptive Control In Milling Special Spiral Rod

Because the geometrical shape of the special spiral rod is complicated, it is difficult to calculate the cutting width and thickness in the process of manufacturing a special spiral rod. At present, there is no calculation method for this kind of work piece's cutting quantity. So when a numerical control program is being made, the cutting quantity can only be decided by experience or according to the cutting quantity handbook. This prevents the envelope method of processing special spiral rod to show its high efficiency fully.In this paper, according to the characteristics of the special spiral rods' processing, the feasibility of adjustment of the feed velocity has been justified and quasi-adaptive control system has been established. Through measuring the signal of the spindle motor's power, which is regarded as the control object to adjust the feed velocity in the NC program, the efficiency has been improved according to the control rules with the cutting precision satisfied.In the process, because of the shape of the work piece, the signals, which can indicate the cutting state, such as cutting power, vibration, and acoustic emission, change periodically; so quasi-adaptive control system can be applied in this process. After all kinds of signals have been analyzed, the cutting power is chosen to inspect the process. The cutting power is easy to detect and implement in practice.The relationship of the cutting precision and the main spindle motor's power and the feed velocity in the process has been analyzed in the paper and the feasibility of improving the efficiency by adjusting the feed velocity has been justified in the process of milling special spiral rod. On the basis of analysis above-mentioned, the control thoughts and method of the Iterative Learning Control system have been applied, and a system with one input and one output was designed, it has been proved that using this system to control the process of manufacturing a special spiral rod can gain satisfied effect.The quasi-adaptive control system established in the paper is to quantify and adjust the feed velocity with respect to the cutting precision and the rated power of the main spindle motor constraint. It can improve the efficiency availably and it can be used in the process of manufacturing the special spiral rods with all kinds of shape. The control system made an attempt to apply iterative learning control to the quasi-adaptive control system in milling special spiral rod and it is a further exploration in the field of control of processing the special spiral rod.