适用于动态特性未知工业过程的改进型相联存储自学习控制系统
An Improved Associative Memory Learning Control System for Industrial Processes with Unknown Dynamics
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摘要: 对相联存储自学习控制系统(AMLCS)提出了一种改进方案,可用于动态特性几乎完全未知且慢时变的工业过程.主要改进之点在于:1)过程预报模型及控制策略均取增量形式,以便克服阶跃扰动,并有助于减少二者所需用的相联存储系统(AMS)的内存占用量;2)在按领先多步的子目标对当前控制增量进行优化过程中引入钝化因子,以使原属多变量优化的问题简化成单变量优化的问题;3)对AMS提出了新的寻址机制,致使其内存占用量大为减少,同时又避免了原有杂凑寻址作法所引起的数据冲撞问题;4)在用于过程预报模型的AMS中采用局部线性外推法进行主动学习,既使学习收敛过程得以通过预先扩大已训域而加快,又避免对控制品质产生不利影响.数字仿真结果表明了这种AMLCS新方案的可行性和有效性.Abstract: This paper proposes an improved version of the associative memory learning control system (AMLCS) for industrial processes with almost completely unknown but slowly time-varying dynamics. The main improvements introduced are: 1) Both the predictive process model and the control strategy are in the incremental form, in order to cope with the stepwise disturbances and also to reduce the required memory sizes of the associative memory systems (AMSs) for them; 2) The multi-step ahead subgoal oriented optimization for the current control increment is simplified by introducing a blunting factor.Thus, the original multivariable optimization can be reduced into a singlevariable one; 3) A new addressing mechanism for the AMS is presented so as to reduce the required memory size greatly without the collision problem due to the hash-coding; 4) A local linear extrapolation approach is used in the active learning procedure of the AMS for the predictive process model so as to enlarge its trained region and hence to quicken the convergence of learning without any harmful influence on the control quality. Numerical simulations have shown the feasibility and effectiveness of the new AMLCS proposed.