【作者】 柏艳红；

【导师】 李小宁；

【作者基本信息】 南京理工大学 ， 机械制造及其自动化， 2006， 博士

【摘要】 气动技术因其特有的优点而广泛应用于自动化生产的各个领域，由于实际的需求和技术的推动，促使其向更精密的伺服控制方向发展。但是，由于气动伺服系统的强非线性，对其实现高精度的有效控制一直是个难题。迄今为止，学者们主要针对气动直线位置伺服控制进行了大量的研究，而对气动旋转位置伺服控制的研究很少。在工业自动化和机器人领域，存在大量的旋转位置伺服控制需求，因此，对气动旋转位置伺服控制的研究具有实际的应用价值。 摆动气缸是一种常见的气动旋转驱动装置，由于摆动气缸较小的行程和较大的摩擦力矩使得对其实现高性能的位置伺服控制比较难，目前摆动气缸伺服定位的精度还不能满足实际应用的需求。论文对比例流量阀控制的摆动气缸位置伺服系统的系统非线性特性的补偿方法、线性化数学模型的建立方法以及能够适应负载变化的控制策略等方面进行了深入的理论分析和实验研究。 首先基于理论分析和实验，研究了与控制过程相关的系统特性，即工作点位置、负载大小和摆动气缸两腔初始压力等工作参数以及摩擦力矩对系统特性的影响，分析了系统存在的粘滑振荡现象、位移波动现象等产生的原因。 针对比例流量阀的非线性特性和系统的位移波动现象，提出了两种相应的辅助控制方法：比例阀输入输出线性化的非线性补偿方法，位置控制+压力差辅助控制的复合控制方法。非线性补偿方法能够减弱系统的非线性强度，改善系统特性，降低系统的控制难度，也为建立更准确的线性模型打下了基础。位置控制+压力差辅助控制的复合控制方法则可以有效避免位移波动现象的发生，提高系统的定位精度。 为了避免摩擦力矩这一非线性因素对模型准确性的影响，提出了一种能够更准确地反映系统特性的线性化数学模型的建立方法。该方法在充分考虑压力差动态过程与摩擦力矩无关这一特点的基础上，将压力差动态过程用近似线性化方程表示，并与运动方程相结合构成三阶状态空间线性模型，采用系统辨识的方法确定模型参数。同时，为了补偿比例流量阀的非线性特性，提高线性模型的准确性，将比例阀非线性补偿环节和比例流量阀控摆动气缸系统看作一个整体，作为辨识对象。又考虑到系统特性与工作点位置有关这一特点，采用了定位辨识法。通过实验研究，验证了该方法的可行性。 为了解决系统在压力差反馈控制下稳态误差较大的问题，提出了比例+速度和压力差微分反馈控制方法(PVDDP)。根据所建线性化数学模型，从理论上分析了该方法的可行性。实验结果表明，PVDDP控制在工作点位置和负载变化较小时可获得较好的控制效果，但是适应负载和工作点位置大范围变化的能力较差。更多还原

【Abstract】 Pneumatic technology has been widely used in industrial automation area because of its unique advantages. The actual requirements and technical impetus motivate the development of the pneumatic servo technology. However, due to its strong nonlinearities, it is difficult for a pneumatic servo system to achieve higher control precision. So far, most of the research work reported has been focused on the position control of the linear cylinder, and fewer researches on the position control of the rotary actuator were reported. In the fields of industrial automation and robot, there is a wide requirement for rotation position servo control. Therefore, it is of practical value to conduct study on the pneumatic rotation position servo control.Pneumatic rotary actuator is an actuating device of rotation motion used widely in pneumatic systems. However, its smaller stroke and larger friction torque make it more difficult to implement angular position servo control of high performance. At present, the positioning precision couldn’t meet the practical requirement. In this paper, a pneumatic rotary actuator position servo system with proportional flow valves as the control devices is studied. The study is conducted in the following aspects: compensation method of the nonlinear characteristics, method of establishing linear model, control strategy and so on.System characteristics are investigated thoroughly through theoretical analysis and experiments. The influence of the nonlinear friction and the operating parameters, including positions of the operating points, magnitude of the payloads and the initial pressures in the two chambers, is studied first. Then, some particular phenomena such as stick-slip oscillation and displacement fluctuation around the desired position are analyzed.Corresponding to the nonlinear property of the proportional flow valve and the displacement fluctuation phenomenon of the system, two auxiliary control approaches are proposed. One is the compensation method of the valves’ nonlinear property, and the other is the composite control scheme integrating position control mode with pressure difference auxiliary control mode. Using the nonlinear compensation method, the system characteristics can be improved and the control of the system can be facilitated. With the composite control scheme, the displacement fluctuation phenomenon can be avoided effectively and the positioning accuracy can be improved.To minimize the influence of the nonlinear friction torque, a method of establishing linearized mathematic model that can reveal the system behaviors more precisely is更多还原