The Research On Radial Micro-feeding Mechanism For Boring Piston Non-circular Pin-hole Based On Piezoelectric Actuator

The piston non-circular pin-hole can reduce the centralized stress and improve the load capacity of pin-hole effectively, and the work life of piston is also extended. The key technique of boring pin-hole is to obtain the controllable and high frequent radial micro-motion while the boring tool is turning quickly with spindle. So this method has more strict requests on micro-displacement mechanism.This thesis puts forward a new solution of radial micro-feeding mechanism, which uses two piezoelectric actuators as the force driver of feeding motion. By using the inverse control method under open-loop operation based on the hysteresis model, the two piezoelectric actuators can achieve cooperative movement, that is to say, one lengthens by adding voltage while another shortens by reducing voltage. So the flexure hinge mechanism is driven and carries boring tool to achieve high frequent and precise radial displacement. The main work is illustrated as follows.1. According to the analyses of manufacturing theory and methods for piston non-circular pin-hole, the key techniques required by NC Machining are educed.2. The displacement characteristics of piezoelectric actuator are tested and analyzed. By means of mathematic method, a simple and practical mathematic formula describing the hysteresis of piezoelectric actuator is proposed. The inverse control method under open-loop operation based on this hysteresis model is demonstrated by experiment. As a result, the model is effective in diminishing the errors arising from nonlinear hysteresis.3. Based on the right angle flexure hinge, a flexure micro-feeding mechanism is designed, and the mechanics analysis and safety checkout are also done. A finite element method (FEM) is applied to analyze the static and dynamic characteristics of the mechanism.4. A drive method and corresponding control theory of using two piezoelectric actuators to work together are expatiated. The experiment for validating the correction of the solution is made. The test results indicate the whole mechanism device and the drive method are feasible.Researching the non-circular piston pin-hole and designing manufacturing device have great practical and economical value.This thesis makes a meaning exploration and try in manufacturing piston pin-hole and applying piezoelectric actuator.