磁流变-气浮复合驱动精密运动平台的非线性刚度与可控阻尼的协调致稳特性及控制策略研究

A precision motion stage driven by composite actuators with magnetorheological (MR) fluids and air bearings (CAMFAB) is proposed, which employs air floating technology to generate nonlinear stiffness with frictionless motion, and utilizes MR effect to generate controllable damping with fast response, and has advantages of flexible switching in passive and active control manners for multiple applications. The precision motion stage will be suitable for accurate positioning with small or medium load capability, long stroke and high precision in many engineering fields such as aerospace, precision finishing etc.. However, the strong coupling and nonlinear behaviors in mechanic-electric-magnetic physical fields due to complex MR effect and floating effect of the CAMFAB brings about complex system control and analysis of static/dynamic characteristics. Moreover, there are actuator saturation, sensor errors, measurement noises in the system and dissipation of damping force for the magnetorheological fluid valve, and then great challenges are faced for high precision control of the precision motion stage driven by CAMFAB. In this project, the prototype of CAMFAB with power generation is firstly developed and has a positioning precision about micron, and the precision stage driven by CAMFAB is presented. The dynamic and static characteristics of variable damping from MR effect and nonlinear stiffness from frictionless pneumatic spring will be analyzed through nonlinear analysis technology in both frequency and time domain. Gap leakage of air floating and leakage model of mid-position in valve will be researched to realize the system output of high precision and high speed/accleration. Stabilizing principles of nonlinear stiffness and controllable damping in a coordinated manner are consequently obtained along the instructions of exploring appropriate dynamic modulus to improve composite performances in both time and frequency domains. Then a constrained optimization adaptive robust controller in which energy dispassion of MR damping and physical limitation of dynamics and actuators are considered is synthesized with integrations of coordinated stiffness and damping as well as effective observer technology for low-frequency disturbances to realize precision positioning with high speed and high accuracy, adaptive load capability and strong anti-disturbance and vibration rejections.

磁流变-气浮复合驱动精密运动平台采用气浮效应产生无摩擦的非线性刚度，采用磁流变效应产生快速响应的可控阻尼，具有多功能主被动灵活控制的特点，在航空航天、精密加工等领域的中轻载、大行程、高精度运动系统上将有较好适用性。但是，磁流变与气浮效应的气-液-磁-电多物理场的强耦合与非线性增加了系统控制和动静态分析的难度，并存在驱动饱和、传感误差、观测噪声、磁流变阻尼力耗散约束等问题，给其高精度控制带来挑战。本项目将研制实现微米级定位精度的自供能磁流变-气浮复合致动器及其精密运动平台；研究气浮间隙泄漏和阀口中位泄漏模型保证高精度与高动态输出的可实现性；分析动态模量对系统时频域综合性能的影响来获得非线性刚度与可控阻尼的协调致稳规律；设计基于阻尼力耗散与动力学约束的受限优化自适应鲁棒控制器，并结合动态干扰观测、最佳刚度与阻尼的直接逆映射，实现复合驱动系统高速高精度定位、承载自适应性和较高的抗干扰性能。

本项目提出一种新原理的磁流变-气浮复合致动器及其驱动的精密运动平台系统。以探索磁流变-气浮复合致动器的结构优化设计，分析非线性刚度与可控阻尼协调实现系统动静态性能提升的控制规律，并结合受限优化自适应鲁棒控制方法实现复合驱动精密运动平台系统的高运动性能为研究目标。项目的主要研究成果有：(1)提出了新型的能量回馈型磁流变-气浮复合致动器原型设计及其驱动的精密运动平台系统，其通过气浮效应产生无摩擦可调刚度来提高执行器的输出力和响应能力，通过磁流变效应产生快速可控阻尼来提高定位运动的稳定性和抗干扰性，采用电磁发电的能量回馈设计来提升系统的节能效率。(2)建立了磁流变-气浮复合驱动系统的动静态输出性能分析模型，提出了磁流变系统和气浮无摩擦系统满足结构制约和应用需求的性能导向分层参数受限优化设计方法，获得系统在硬件和环境限制下输出性能的极限提升。(3)通过综合磁流变-气浮系统的压力动态、运动动态与阀口压降等关系，建立与系统结构设计参数相关的磁流变-气浮复合系统的机-电-磁-液耦合动力学模型，获得可调气弹簧刚度与磁流变阻尼对系统动态响应性能的影响关系。(4)针对磁流变-气浮复合驱动系统，提出基于阻尼力耗散特性和系统动力学约束的受限优化自适应鲁棒控制方法，获得了精密运动平台系统的高速高精度运动性能和较强的稳态抗干扰特性。(5)分析了具有多组磁流变阀调节的磁流变电液系统运动的工作模式和输出效率，提出了磁流变系统的多变量阻尼协调控制方法，并与受限优化自适应鲁棒运动控制方法相结合，实现了其高精度位置运动控制和较强的鲁棒抗干扰运动性能。所研究的基于性能导向的磁流变系统受限优化设计和结合可控刚度与阻尼协调的受限优化自适应鲁棒控制方法，为具有可调刚度和阻尼的一类非线性机电系统的有效控制设计提供理论支撑，具有重要的现实意义。