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电液位置伺服系统是复杂的非线性控制对象,存在各种建模不确定性,使得设计高性能的控制器以满足系统伺服精度要求更加困难。针对考虑各种建模不确定性的电液位置伺服系统,设计了一种具有自适应增益的超螺旋滑模控制方法。利用已知的系统模型信息,在传统超螺旋滑模控制算法中引入基于模型的前馈控制律,提升系统伺服精度。采用自适应律实时更新控制器增益,无需先获知系统建模不确定性的确切界,避免了传统算法中由人为设定与该界相关的控制增益造成的保守性。基于Lyapunov稳定性理论证明了闭环系统全局稳定,系统跟踪误差可在有限时间内渐近收敛到零附近任意小的范围内,且收敛的速度和稳态误差的界可通过参数进行调节。仿真结果表明,所提出的控制方法可有效地抑制建模不确定性对系统的不利影响,显著提高其跟踪精度,且所得到的控制输入是连续的,更利于实际应用。
Electrohydraulic position servo system is a complex nonlinear control object, there are a variety of modeling uncertainties, making the design of high-performance controller to meet the system servo precision requirements more difficult. Aiming at the electro-hydraulic position servo system considering various modeling uncertainties, a super-helical sliding mode control method with adaptive gain is designed. Using known system model information, a model-based feedforward control law is introduced into the traditional super-helical slipform control algorithm to improve the system’s servo precision. Using adaptive law to update the gain of the controller in real time, it is not necessary to know the exact boundary of system modeling uncertainty first, which avoids the traditional conservativeness caused by artificially setting the control gain associated with the boundary. Based on the Lyapunov stability theory, the global stability of the closed-loop system is proved. The tracking error of the system can converge asymptotically within a finite time to any small area around zero. The bound of the convergence speed and the steady-state error can be adjusted by the parameters. The simulation results show that the proposed control method can effectively suppress the adverse effects of modeling uncertainty on the system, significantly improve the tracking accuracy, and the resulting control input is continuous, more conducive to practical application.