自适应重复学习算法在岩土动态应力试验中的应用

摘要

岩土实验机的执行机构与被压试样都具有非线性、时变特性,针对周期性动态应力波形的跟踪问题,在结合传统PID控制算法基础上,提出一种自适应重复学习控制算法.依据不同的控制过程增加了不同的计算模型和控制参数,进而设计了自适应重复学习控制器,通过斜率差值法和误差均值法对比例增益和偏差进行自适应调整,通过重复学习对自适应结果进行优化.通过实际实验验证了该算法的稳定性和收敛性,从而保证了非线性负载所承受的动态应力能够准确跟踪设定的动态波形.目前,该算法已应用于1000 kN多功能三轴试验仪正弦波和三角波的波形跟踪.%The actuators of the geotechnical experiments machine and the pressured samples have the characteristics of non-linear and time-varying.So,for the periodicity tracking problem of the dynamic stress waveforms,an adaptive repetitive learning control algorithm is proposed based on the traditional PID control algorithm.Different calculation models and control parameters are added according to the different control processes.Furthermore,an adaptive repetitive learning controller is designed.The proportional difference method and the error mean method are used to adaptively adjust the proportional gain and the deviation,and the adaptive results are optimized by repetitive learning.The stability and convergence of the algorithm are verified by practical experiment,which ensures that the dynamic stress of the nonlinear load can accurately track the set dynamic waveform.At present,the algorithm has been applied to waveform tracking of sine wave and triangular wave for 1000 kN multi-function triaxial test instrument.