【作者】 查宏民；

【导师】 阎祥安；

【作者基本信息】 天津大学 ， 机械电子工程， 2005， 硕士

【摘要】 气压传动系统由于价格低廉、结构简单、工作可靠、无污染等优点,在工厂自动化和机器人驱动系统中得到了越来越广泛的应用。由于气动系统的一些固有特点,如气体的可压缩性、阀的非线性、气缸的摩擦力特性以及系统参数易受环境的影响等,这些特点在很大程度上增加了气动位置控制系统的控制难度,很难满足工业上高精度的定位要求。本文对由比例方向阀和单活塞杆气缸组成的气动位置系统特性进行研究的基础上,通过对控制策略的理论研究和仿真分析,实现了气动位置系统的高精度控制。首先,建立了阀控缸系统的非线性数学模型,对系统特性进行了研究,讨论了系统参数对系统特性的影响;在此基础上,对气动比例位置系统进行了相应的控制策略的研究。提出了本文采用的控制策略:步进PID控制和模糊自适应PID控制。步进PID控制使输入信号一步一步地逼近所要求的位置,使运行对象平稳,适合高精度定位系统的定位要求。模糊PID控制应用模糊推理的方法,实现PID参数的在线自调整,能够达到参数kp,ki,kd取值的动态变化,使系统动态过程各阶段的PID参数处于最佳状态,以获得满意的控制效果。其次,应用MATLAB/Simulink,设计了本实验系统的仿真界面。详细地分析了系统的时域特性、频域特性。对步进PID控制方法和模糊自适应PID控制方法进行了计算机仿真。仿真结果表明,同传统PID控制相比,步进PID明显地改善了系统的响应特性,提高了定位精度,其软件仿真定位精度小于0.1mm。应用模糊自适应PID控制方法,系统的超调量为0.07%,稳态精度可达0.07mm。较好地结合了模糊控制灵活和适应性强的优点与PID控制精度高的特点,具有较强的鲁棒性。最后,对系统进行了动态仿真。仿真结果证明了所建数学模型和所采用的控制策略的正确性。更多还原

【Abstract】 Since pneumatic system has the advantages of low cost, simple construction,reliable in work, no air pollution, it has been widely used in the fields of factoryautomation and robot driving system. However, the inherent characteristics of thepneumatic system, such as the condensability of the air, nonlinear of valve, frictioncharacteristic of pneumatic cylinder and easily influenced by environment factors,greatly increased the control difficulty in a degree, and hard to satisfy the orientationrequest in industry.Based on the characteristics of pneumatic position system with proportional valveand single piston, a high precision control of the system is achieved by researching andsimulation analysis of the control strategy.First, a nonlinear mathematic model is built, the characteristic is researched, andthe affect of system parameters to the characteristic is discussed. The Step PID controland Self-adaptive Fuzzy-PID control are put forward. The input signal is approached tothe expect position length by length through Step PID control which can stable theobject and adapt to the request of high precision orientation control. By fuzzyreasoning, the PID parameters can be adjust on line, and its value is changed dynamicso as to keep the optimal state at every moment in order to obtain the approvingcontrol effect.Second, the simulation interface is designed by using the MATLAB/SIMULINKtool. The characteristic in time and frequency domains of the system is analyzed indetail. The simulation is done to the step PID control and self-adaptive Fuzzy-PIDcontrol method. The results show that: compared to the traditional PID control method,Step PID control can improve the respond characteristic and orientation precisionclearly. The simulation result of orientation precision is under 0.1 mm. The overshootis 0.07 percent by Self-adaptive Fuzzy-PID control, and steady error is 0.07 mm. Thiscontrol method is combined with excellences of agility and strong adaptability ofFuzzy control and high precision of PID control, and has strong robustness.Last, a dynamic simulation is done. The results validate the correctness ofmodeling and the control methods.更多还原