一类非匹配不确定纯反馈非线性系统新型变幂次趋近律滑模控制

发布时间：2018-07-24 10:33

【摘要】：针对以熔化极气体保护焊(gas metal arc welding,GMAW)为代表的一类非匹配不确定纯反馈非线性系统的输出问题,提出一种基于变幂次趋近律的滑模控制方法。首先,采用滑模微分器得到含系统非匹配不确定性干扰的输出一阶导数。得益于终端滑模有限时间稳定的性能,该方法具有估计精度高、估计误差收敛速度快的优点。然后,提出一种新型的变幂次趋近律,并证明在相同增益下,其趋近速度均快于现有各种趋近律,且具有自适应调节趋近速度的能力,既保证了在全局范围内系统轨迹有限时间趋近滑模面,又避免了在滑模面附近出现抖振。最后,采用变幂次趋近律滑模变结构控制方法和传统趋近律滑模变结构控制方法分别对带有非匹配干扰的GMAW中的弧长进行控制仿真,并对比弧长跟踪效果,分析稳态误差。结果表明,变幂次趋近律滑模变结构方法能够有效的提高系统收敛的快速性,滑模控制方法对于非匹配不确定非线性系具有强鲁棒性。
[Abstract]:A sliding mode control method based on variable power law is proposed to solve the output problem of a class of non-matching uncertain pure feedback nonlinear systems represented by (gas metal arc welding-GMAW. First, the first order derivative of the system with mismatched uncertainties is obtained by using the sliding mode differentiator. Due to the finite-time stability of the terminal sliding mode, the proposed method has the advantages of high estimation accuracy and fast convergence rate of estimation error. Then, a new variable power law is proposed, and it is proved that under the same gain, the speed of approach is faster than that of existing laws, and it has the ability to adjust the speed of approach adaptively. It can not only ensure that the trajectory of the system approaches the sliding mode surface in finite time in the global range, but also avoid the chattering near the sliding mode surface. Finally, the arc length in GMAW with mismatched disturbance is simulated by using variable power law sliding mode variable structure control method and traditional approach law sliding mode variable structure control method. The tracking effect of arc length is compared and the steady-state error is analyzed. The results show that the variable power law sliding mode variable structure method can effectively improve the rapidity of the system convergence, and the sliding mode control method is robust to the nonlinear system with unmatched uncertainties.
【作者单位】：四川大学电气信息学院;
【基金】：中央高校基本科研业务费专项资金资助(20826041A4133)
【分类号】：TP273

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