【作者】 权建洲；

【导师】 熊有伦； 尹周平；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2010， 博士

【摘要】 H型桁架定位平台机械结构简单、运动稳定性高,在精密测量、数控加工和半导体封装设备中的应用愈来愈广泛。采用直线电机双边驱动后,克服了传统旋转电机和滚珠丝杠驱动方式传动环节多、响应滞后大以及存在非线性摩擦等缺点,可获得更高的速度、加速度和定位精度,适合于半导体芯片封装中的频繁“拾/放”操作和快速点点精密定位。随着运动速度和加速度的增加,桁架系统动力学特性已成为影响系统定位精度和同步性能的重要因素,在控制设计中必须加以考虑。为此,本论文对高速工况下双边驱动H型桁架定位平台的系统动力学建模与同步控制等方面开展研究。主要研究工作如下：(1)基于Euler-Lagrange方程,建立了H型桁架系统的耦合动力学模型。研究了关节刚度对系统频率特性的影响,分析了移动头快速加减速运动引起的扭转冲击对横梁两端同步性能的影响,仿真结果表明通过提高关节的刚度有利于提高系统的振动频率。移动头高加速度快速移动时,将会对横梁产生扭转运动,并诱导结构振荡。(2)双边驱动H型桁架定位平台是典型的多输入多输出(MIMO)耦合系统,在快速定位或跟踪过程中要求最小化同步误差。通过建立包含同步误差及其变化率的线性二次性能指标,将此类耦合系统的同步控制问题转化为线性二次型最优控制问题。通过建立黎卡提等式和李雅普洛夫等式,计算出包含有交叉耦合补偿的控制律。研究了同步误差及同步误差变化率加权系数α、β值对同步性能的影响,仿真结果表明增大加权系数α、β值有利于改善系统的同步性能,同步误差对权系数β值的取值更为敏感。(3)针对H型桁架定位平台采用线性二次最优同步控制当出现扰动时鲁棒性变差的问题,结合滑模变结构控制和线性二次优化控制各自优点,设计了滑模变结构最优同步控制器。滑模变结构控制抑制外部干扰的影响,增强系统的鲁棒性,线性二次最优控制用于改善系统的动、静态性能。设计了简单的扰动估计器,通过自适应律对扰动上界进行预估,实现了在未知扰动上界的情况下仍能保证控制系统的鲁棒性。(4)结合双边驱动H型桁架定位平台在RFID电子标签贴装设备中的工程应用,进行了同步控制系统的设计,包括具有同步误差补偿功能的同步控制设计、同步误差保护和同步轴回原点等内容,给出了具体实现方法和实验结果。最后对本文提出的理论成果进行了实验验证。更多还原

【Abstract】 H-type gantry stages, well characterized by the simple structure and high stability, have been widely adopted in precision metrology, NC machining, and semiconductor packaging equipments. The bilateral linear motor driving is superior to the traditional ballscrew driving by conquering its drawbacks which is characterized by lots of transition elements, the sluggish response and nonlinear friction, etc. Thus, higher acceleration/deceleration, accuracy can be easely obtained, which adapts to frequent pick-and-place operations and fast precise point-to-point (PTP) motions in the semiconductor packaging industry. However, with the increase of speeds and accelerations, the dynamic characteristic of the gantry turns out to be the significant impacts on the system positioning accuracy and synchronous performance. Therefore, this paper investigates the dynamic modeling and synchronous control of a bilateral drive gantry stages under the condition of high speed. The major work herein is as follows:(1) Based on the Euler-Lagrange equation, this paper builds up the coupling dynamic model of the H-type gantry stage. Furthermore, two problems are theoretically investigated in detail. First, the effect of the joint rigidity on systematic frequency characteristics; second, the effect of the torsion impact on the synchronous performance of the gantry which is induced by the moving head’s rapid acceleration and deceleration motions. Simulations indicate that the systematic bandwidth could be enlarged by enhancing the joint rigidity. When the moving head performs high acceleration motions, torsion impact would be notably present which may induce structural vibration. Therefore, advanced control algorithms should be developed to suppress the aforementioned negative effects.(2) Bilateral drive H-type gantry stages, a kind of typical coupling MIMO system, require to minimize the synchronous error during the trajectory tracking and positioning. Through establishing the linear quadratic performance specifications containing synchronous error and its differential, the synchronous problem of coupling MIMO system can be transferred to a linear quadratic optimal control problem. And control laws satisfying performance specifications are calculated through the Raccati equation and Lyapunov equation. The effects of weight coefficients a andβon the synchronous performance are analyzed, which revise the synchronous error and its differential, respectively. Simulations indicate that higher a andβcan add to the systematic synchronous performance, and the synchronous error is more susceptible to the value ofβ.(3) As the systematic robustness deteriorates in case of disturbance in the linear quadratic optimal synchronous control, a sliding structure optimal synchronous controller is proposed, which integrates the sliding-mode variable structure control and the linear quadratic optimal control. The former is intended for suppressing the surrounding disturbance, while the latter for reshaping the dynamic and static performance of the system. Also, a simple disturbance observer is designed to estimate the upper bound of disturbance through an adaptive law, which implements the systematic robustness under the condition of unknown upper disturbance bounds.(4) A dual-axies synchronous control system is developed. Synchronization controller with the synchronization error compensation is designed, and synchronous error protection and homing of the dual-axies are implemented. It has been applied to the RFID tag assembly of equipment, experiment and application results show that the effectiveness of control method.更多还原