摘要
虚拟轴机床系统模型复杂难以准确建立,高速加工时存在强烈干扰且不确定,难以实际实现高性能控制,为此,提出一种新型自适应动态滑模控制方法,用于虚拟轴机床并联机构运动控制。通过构建新型动态切换函数,设计二阶动态滑模控制,以解决采用常规等效控制设计的滑模控制系统,因忽略执行机构快变动力学特性等而导致控制系统品质降低甚至不稳定的问题,同时避免滑模抖振的出现;引入自适应控制对虚拟轴机床加工时的外界干扰等不确定因素进行在线估计,以克服滑模控制性能需依赖于对未知干扰的先验估计的局限,增强虚拟轴机床克服高速加工时的强烈干扰的能力,进一步提高其控制性能。仿真和试验结果表明,采用自适应动态滑模控制方法,可使虚拟轴机床控制系统具有较好的自适应能力,较强的鲁棒性,良好的动态、稳态品质。
To further enhance the control performance of the virtual axis machine tool with a complex system model which can not be accurately established and with the nonlinear,strong coupling characteristics,a novel adaptive dynamic sliding mode control method is proposed for the motion control of the parallel mechanism of the virtual axis machine tool.A second-order dynamic sliding mode control is designed by building a new dynamic switching function to solve the problem of the reduced control quality and even the system instability of the conventional sliding mode control system based on the equivalent control design,due to the neglect of the fast changing dynamics of the actuators,and to avoid the chattering of the sliding mode.The adaptive control of estimating online the external interference of the virtual axis machine tool is adopted to overcome the dependence of the sliding mode control performance on the prior estimate of the unknown interference,and enhance the ability of the high-speed processing virtual axis machine tool to resist the strong interference.Simulation and experiment results show that the proposed adaptive dynamic sliding mode control method can be an effective solution to the control of the nonlinear,time-varying,coupling virtual axis machine tool with the strong disturbance in high-speed machining.It can ensure the control system a strong robustness and a good dynamic,steady quality.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2012年第11期119-125,共7页
Journal of Mechanical Engineering
基金
江苏省自然科学基金(BK2009202)
江苏省高校优势学科建设工程(苏政办发(2011)6号)
镇江市科技支撑计划(NY2011013)资助项目
关键词
虚拟轴机床
并联机构
动态滑模控制
自适应控制
Virtual axis machine tool Parallel mechanism Dynamic sliding model control Adaptive control
