Adaptive control in high-speed electric drives of a lathe feed for noncircular turning

Abstract

Problems of upgrading high-speed electric drives of a lathe feed for machining such bulk and precise products of engineering industry as internal combustion engine pistons with a complex ovate-barrel-like shape are considered. It is shown that these electric drives must have astaticism with respect to chip loading to decrease shape errors. When machining the piston surface, there are both uninterrupted cutting zones and cutting zones with an interruption on part of the spindle revolution as well (for example, when passing bores by a cutter etc.). It is shown that, at the same time, it is reasonable to have the structure with an integrally proportional controller and in the case of cutting interruption with a proportional controller. A controller is proposed with the structure changed as a function of the cutting feature. Application of the adaptive controller with the variable structure in the control system of lathe feed drives for noncircular turning decreases the shape error caused by uninterrupted cutting by 5–20 times in comparison with the linear integrally proportional controller. The additional effect of the application of the adaptive control is attained due to a significant (by several times) increase in the useful life of an expensive diamond cutting tool. The control of the controller structure is effective both in systems with the software formation of controlling actions and in systems using self-training principles.