适用于大椭圆高速车削的刀架系统关键技术研究

发布时间：2019-03-14 17:28

【摘要】：对于重型发动机,活塞在工作过程中由于受到侧压力、高温、高负荷等作用,产生膨胀变形。为了改善活塞与缸壁间的配合间隙,大功率活塞外圆截面设计为大椭圆度组合型线,复杂的外形和高频响高精度要求大大增加了外圆型面的加工难度,也提高了对控制系统高实时性的控制需求。目前广泛采用的加工方式是基于PC的全数控车床。制约大椭圆度高速车削的关键技术主要包括:(1)基于加速度最小冲击条件下组合椭圆轨迹规划;(2)高频响刀架驱动系统PID智能自整定技术。本文主要针对适用于大椭圆度高速车削的直线伺服刀架系统进行加工轨迹优化和控制技术研究,以提高伺服刀架系统的快速跟踪性能,减小加工误差,主要研究内容如下:(1)对活塞外圆的型面特征及数学模型进行分析概括,指出了截面为组合型线的大椭圆度外圆现有设计方法的不足,提出了三种基于极小冲击的型线重构优化方法,通过MATLAB从理论上分析其合理性。(2)为了提高系统的快速响应能力,避免因系统反馈滞后等因素对加工精度造成的不良影响,基于前馈思想,在直线伺服刀架三环控制中加入加速度前馈对误差进行补偿,并通过仿真验证了其可行性。(3)设计了一种模糊自适应PID控制器,将传统的PID控制与智能控制算法中的模糊控制进行结合,实现了直线伺服刀架三环控制中位置环和速度环参数的自整定,并将其与传统的PID控制方式进行对比。(4)介绍了适用于大椭圆车削加工的直线伺服刀架系统的硬件结构和运动控制方式;通过空载加工实验,验证了电流环的加速度前馈补偿有利于提高系统的快速响应能力;通过实际车削实验,验证了删除型值点重构优化型线能有效减小冲击,提高加工精度,证明了研究内容具有实际应用意义。
[Abstract]:For heavy-duty engine, the piston is subjected to side pressure, high temperature, high load and so on in the process of working, resulting in expansion deformation. In order to improve the fitting clearance between piston and cylinder wall, the outer circle section of high power piston is designed as a large ellipticity composite line. The complicated shape and high precision requirements of high frequency response greatly increase the machining difficulty of the outer circular surface. It also improves the real-time control requirements of the control system. At present, the widely used machining method is the full digital control lathe based on PC. The key technologies for high-speed turning with high ellipticity include: (1) combined elliptic trajectory planning based on minimum acceleration impact and (2) PID intelligent self-tuning technology for high-frequency loudspeaker drive system. In this paper, the machining trajectory optimization and control technology for linear servo tool holder system suitable for high-speed turning with high ellipticity are studied in order to improve the fast tracking performance of servo tool holder system and reduce the machining error. The main research contents are as follows: (1) the characteristics and mathematical models of the piston outer circle are analyzed and summarized, and the shortcomings of the existing design methods for the large ellipticity outer circle with the section of the composite profile are pointed out. Three optimization methods of profile reconstruction based on minimal impact are proposed, and their rationality is analyzed theoretically by MATLAB. (2) in order to improve the quick response ability of the system and avoid the adverse effect on machining accuracy caused by the feedback lag of the system and so on, the optimization method of profile reconstruction based on minimal impact is proposed. Based on the feed-forward idea, acceleration feedforward is added to the three-loop control of linear servo tool holder to compensate the error, and its feasibility is verified by simulation. (3) A fuzzy adaptive PID controller is designed. Combining the traditional PID control with the fuzzy control in the intelligent control algorithm, the self-adjusting parameters of the position loop and the velocity loop in the three-loop control of the linear servo tool holder are realized. It is compared with the traditional PID control mode. (4) the hardware structure and motion control mode of the linear servo tool holder system suitable for large ellipse turning are introduced. Through no-load machining experiments, it is verified that the acceleration feedforward compensation of the current loop is beneficial to improve the fast response ability of the system. Through the actual turning experiment, it is proved that the deleted point reconstruction optimization line can effectively reduce the impact and improve the machining accuracy. It is proved that the research content has practical application significance.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG519.1

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