一类二阶非线性系统的准滑模无模型自适应控制  

Quasi-sliding mode model-free adaptive control for a class of second-order nonlinear systems

作　　者：朱泽 朱战霞[1] ZHU Ze;ZHU Zhan-xia(School of Astronautics,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西北工业大学航天学院,西安710072

出　　处：《控制与决策》2024年第8期2663-2670,共8页Control and Decision

摘　　要：为实现一类二阶非线性系统的轨迹跟踪控制,设计一种准滑模无模型自适应控制算法(quasi-sliding mode-model free adaptive control,SM-MFAC).首先,将模型分解为串联的两个离散子系统,并给出整体系统伪偏导数(pseudo partial derivative,PPD)的表达式;然后,利用两个子系统的输出数据设计出子系统2输出的期望状态,进而通过MFAC(model free adaptive control)对在线更新的期望状态进行不断追踪来实现对整体目标的跟踪控制;接着,对SM-MFAC控制系统进行稳定性分析,证明系统输出误差渐进跟踪到零的某个邻域内和等效控制输入是有界的;最后,以自由漂浮空间机械臂的关节轨迹跟踪控制为例验证SM-MAFC控制理论,在多体运动学与动力学仿真软件MBdyn中搭建一个平面两连杆的自由漂浮空间机械臂,关节系统中存在死区、输入饱和以及摩擦特性,通过在Matlab-simulink中的联合仿真表明:MFAC控制方案无法准确地估计出该类二阶非线性系统整体PPD的数值,导致控制性能降低,而所设计的SM-MFAC控制器相对于PID(proportional-integral-differential)、基于比例-微分(proportional-differential,PD)的MFAC可以更快更准确地追踪目标曲线.A quasi-sliding mode model-free adaptive controller(SM-MFAC)is designed for trajectory tracking control of a class of second-order nonlinear systems.First,the model is decomposed into two discrete subsystems in series,and the expression of the whole system pseudo partial derivative(PPD)is given,then we use the output data of the two subsystems to design the expected state of the output of subsystem 2.By using the MFAC to continuously track the expected status of online updates,the tracking control of the overall goal is realized.Then the stability of the SM-MFAC control system is analyzed,it has been proven that the output error asymptotically approaches some neighborhood of zero and the equivalent control input is bounded.Finally,the SM-MAFC control theory is verified by taking the joint trajectory tracking control of a free-floating space manipulator as an example.A two-linked free-floating space manipulator is built in multi-body kinematics and dynamics simulation software MBdyn.There are dead zones,input saturation and friction characteristics in the joint system.The joint simulation in Matlab-simulink shows that the MFAC control scheme can not accurately estimate the overall value of PPD of this class of second-order nonlinear systems,resulting in reduced control performance,the designed SM-MFAC controller can track the target curve faster and more accurately than the traditional PID(proportional-integral-differential),PD(proportional-differential)-MFAC.

关 键 词：二阶非线性系统 滑模控制 无模型自适应控制 伪偏导数 轨迹跟踪 空间机械臂 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]