Repetitive control and its application to linear servo unit for CNC machining of elliptical pistons

Abstract

Absfmcf-in this paper, the basic theory of repetitive control are summarized and modified repetitive controllers are introduced. The steady-state error and asymptotic stability condition are presented. A CNC precision lathe impiemented with repetitive control system for machining elliptical pistons are constructed by a precision linear servomechanism, computer itive controller and a machine-tool. driven directly by the linear servomechanism in radial direction of the piston tracks -section curve of the piston. Compared with the m a c h i~~~g results of a traditional piston CNC machinetools with a PID regular, the tracking error is reduced by 40 %. Keg words--noncircular manufacturing repetitive control linear servomechanism

A new mechanism for boring of noncircular hole and its evaluation via simulation

“…High cutting speeds need to be got for a profitable boring process with good surface finish, which would increase the difficulties in boring of the non-circular hole. To create the wanted micro-displacement, the boring bar must be applied with direct or indirect radial actuation force, which can be got by such mechanisms as linear motor [1], [2], piezoelectric [3], [4], [5], hydraulic [6], voice-coil actuator [7], [8], etc. Due to the features of boring especially for subsize precision parts, it is difficult for above mentioned mechanisms to deliver ideal Manuscript Since the boring bar is in a high-speed rotation, the actuation force must satisfy the following conditions: 1) be exerted by contactless way, 2) rotate synchronously with the boring bar, 3) be great enough to put the boring bar to take a wanted radial micro-displacement about 20ȝor more [9], [10].…”

Design of a Power Amplifier for Magnetic Actuation and Study on Its Actuation Characteristics

“…High cutting speeds need to be got for a profitable boring process with good surface finish, which would increase the difficulties in boring of the non-circular hole. To create the wanted microdisplacement, the boring bar must be applied with direct or indirect radial actuation force, which can be got by such actuators as linear motor [1][2], piezoelectric [3][4][5], hydraulic [6], voice-coil actuator [7][8], etc. Due to the characteristics of boring, it is difficult for above mentioned actuators to deliver ideal movement to the boring bar.…”

A new method for boring of non-circular holes

“…However, this would increase the difficulties in boring the noncircular hole. To create the necessary micro-displacement, the boring bar must be applied with direct or indirect radial actuation force, which can be done using actuators such as linear motor [1,2], piezoelectric [3][4][5], hydraulic [6], voice-coil actuator [7][8], etc. Due to the characteristics of boring especially for small-sized precision parts, it is difficult for the above actuators to deliver an ideal movement to the boring bar.…”