摩擦可控新型气缸调摩方法及其运动和力伺服超高精度控制策略研究

气缸的摩擦力由于存在不确定性和负阻尼特性，阀控缸气动系统超高精度控制难以实现，然其在超精密研抛加工中甚是重要。本项目以突破现有控制精度瓶颈、兼容实现运动和输出力的超高精度伺服控制为目标，开展摩擦可控气缸的调摩方法及运动和输出力控制研究。为满足气缸耗气量小、径向承载力大的气浮无摩擦设计要求，提出基于改进非支配排序遗传算法的多目标优化方法；在气浮实现的前提下，提出基于逆压电效应和超声减摩原理的气缸摩擦力调控方法；针对气动系统控制精度低、抗干扰性能差的问题，研究在线参数自适应估计算法，建立完整全阶非线性数学模型，提出融合刚度极大化思想的改进直接自适应鲁棒控制算法以实现超高精度运动和力伺服控制；对于运动和输出力控制模式间切换时可能出现的突况，提出运动和输出力平滑切换的超高精度自适应鲁棒控制策略使切换平稳过渡，为兼具超高精度运动和输出力伺服控制的摩擦可控气动系统的控制系统研究提供重要的基础支撑。

Because of the uncertainty and negative damping characteristics of pneumatic cylinder friction force, it is difficult to realize the ultra-high precision servo control for valve controlled cylinder pneumatic system. However, the ultra-high precision servo control of pneumatic system is very important for ultra-precision grinding and polishing. To break through the bottleneck of the existing control accuracy and compatibly achieve ultra-high precision servo control of motion and output force, the method of adjusting friction and the control strategies of motion and output force for a novel friction controllable pneumatic cylinder are studied. In order to meet the air float frictionless design requirements of small air consumption and large radial bearing capacity, a multi-objective optimization method based on improved non-dominated sorting genetic algorithm is proposed. On the premise that the piston floats without friction, a method of adjusting and controlling friction based on reverse piezoelectric effect and principle of ultrasonic vibration antifriction is proposed. Aiming at the problems of low control accuracy and poor anti-interference performance of pneumatic system, the on-line parameter adaptive estimation algorithm is studied, a complete full-order nonlinear mathematical model is established, and an improved direct adaptive robust control algorithm with the idea of maximizing stiffness is developed. For the possible sudden instability problem when switching between motion control mode and output force control mode, an ultra-high precision adaptive robust control strategy for smooth switching between two control modes is proposed to make the transition smooth based on the switching control theory. The achievements of the project can provide important basic theory support for developing both ultra-high precision motion servo control system and ultra-high precision output force servo control system of the valve controlled cylinder pneumatic system based on a novel friction controllable pneumatic cylinder.