Dynamic stiffness enhancement of direct linear motor feed drives for machining

Abstract

Lmear motion electric motors have shown promising potential for use as next generation machine tool feed drives since they can increase machining rates and improve servo accuracy by eliminating gear related mechanical problems. TO combat chatter instability, large dynamic stiffness is desirable in the servo control loop.This paper investigates the use of optimal H , control to design for large stiffness.Position feedback alone is first considered, with cutting force feedback later added to augment closed loop stiffness. Optimal position feedback is experimentally seen to achieve up to a 46% stiffness improvement over that achievable with propaionalderivative control. The addition of force feedback to the servo loop resulted in a further 70-100% stiffness improvement over the position feedback alone values.

Modified Loop Shaping Algorithm in Designing 2-DOF Controller of a Ladder-Secondary Double-Sided Linear Induction Motors

“…The connectivity between output controlled system -variable of the linear velocity -and set-point input signals are represented by equation (2).…”

“…Significant effort has been devoted to solving the difficulties in controlling linear motors [8] [9]. Early work includes the based linear robust control methods as proposed by Alter and Tsao in [1]- [2], the disturbance observer (DOB) [9] based disturbance compensation method in [8], and feed-forward nonlinear ripple force compensation in [3]. A precision motion control can also be improved by modifying the three-phase inverter equipment.…”

Performance robustness and stiffness analysis on a machine tool servo design

“…Previous research has discussed machine servo problems in some specific domains like stiction, axes spikes, etc. [1][2][3][4][5][6][7]. Some of the results have tried to add machine intelligence to improve servo performance [8][9][10][11][12][13][14][15][16][17][18].…”

Servo parameter tuning for a 5-axis machine center based upon GA rules

“…The goal of this research is to make the servo engineer's task easier by developing an automated tuning method for these parameters. Because a CNC controller is a very complicated system, most previous works have focused on a subset (or a specific function) of a controller [1][2][3][4][5][6][7]. The few papers that have addressed the entire system have only described the system at the functional level [8].…”