【正文】 Fig. 3. The mechanical model of the elastic drive. M is the load side mass。 ●a rigid link between a motor shaft and a driving pulley of the beltdrive could be adopted。 features, the following assumptions could be made: ●the DCservos operating in the current control mode ensure a highdynamic torque response on the motor axis with a negligible time constant。 each bridgeside is connected to one of the beltdrives. The driving pulleys of the beltdrives are linked to the driving axis, which is driven via the additional beltdrive and the gearbox is used to reduce the speed of the motor. Fig. 2. The drive. . Assumptions The machine drives represent a plex nonlinear distributed parameter system. The highorder system possesses several resonant frequencies that can be observed by the drives39。 ●the laserhead, which directs the laser beam onto the desired position in the cutting plane. Fig. 1. The machine and the controller hardware. The table has to move and position the laser head in a horizontal plane. This is achieved by the means of a drive system with two independent motion axes. They provide movement along the Cartesians39。 Ueda, 1993). Consequently, beltdrives suffer from lower repeatability and accuracy. Moreover, the beltdrive dynamics include more resonance frequencies, which are a destabilising factor in a feedback control (Moon, 1997). Therefore, a conventional control approach like PI, PD or PID control fails to achieve acceptable performance. Plant parameter variations, uncertain dynamics and load torque disturbances, as well as mechanical vibrations, are factors that have to be addressed to guarantee robust system stability and the high performance of the system. An advanced robust motion control scheme is introduced in this paper, which deals with the issues related to motion control of the drives with timing belts. The control scheme is developed on the basis of the motion control algorithm introduced by Jezernik, Curk and Harnik (1994). It possesses robust properties against the disturbances that are associated with a nominal plant model, as it has been developed with the use of the variable structure system (VSS) theory (Utkin, 1992). The crucial part of the control scheme is the asymptotic disturbance estimator. However, as shown in this paper, it fails to stabilise resonant belt dynamics, since it was developed for a rigid robot mechanism. Therefore, this paper introduces an improved motion control scheme, which suppresses the vibrations that would arise due to the nonrigid, elastic drive. Consequently, a rapid response with low position tracking error is guaranteed. The paper is set out as follows. The lasercutting machine is presented and the control plant model of the machine drives is developed in Section 2. In Section 3, the VSS control regarding the elastic servomechanism is discussed and the derivation of the motion control scheme is described. Section 4 presents the experimental results and a followup discussion. The paper is summarized and concluded in Section 5. 2. The control plant . The machine description The lasercutting machine consists of the XY horizontal table and a laser system (Fig. 1). The fundamental ponents of the laser system are: ● the power supply unit, which is placed off the table and thus is not considered in the motion control design。 Disturbance rejection。 Variable structure control。 Servomechanisms。td. All rights reserved.) Keywords: Position control。 徐州工程學院畢業(yè)設計 外文翻譯 學生姓名 學院名稱 機電工程學院 專業(yè)名稱 機械設計制造及其自動化 指導教師 VSS motion control for a lasercutting machine☆ Ales\ Hace, Karel Jezernik*, Martin Terbuc University of Maribor, Faculty of Electrical Engineering and Computer Sciences, Institute of Robotics, Smetanova ul. 17, SI2020 Maribor, Slovenia Received 18 October 1999。 accepted 2 June 2020 Abstract An advanced positiontracking control algorithm has been developed and applied to a CNC motion controller in a lasercutting machine. The drive trains of the lasercutting machine are posed of beltdrives. The elastic servomechanism can be described by a twomass system interconnected by a spring. Owing to the presence of elasticity, friction and disturbances, the closedloop performance using a conventional co