研究了一台机器加工一种工件的简单制造系统的流程控制问题。在对故障时间和工作时间的分布不做任何假设的情况下，利用自适应控制的思想，将整个控制过程依据一定的规则分成有限长的时间段，在每一段时间内用扰动分析估计目标函数的一阶和二阶导数，然后用基于二阶导数的随机逼近算法渐进地估计该流程控制问题中的最优阈值，从而实现了阈值的自适应控制，并利用仿真实例验证了算法的收敛性。 The problem of process control in a simple manufacturing system for machining a workpiece on a machine was studied. In the case of no distribution of failure time and working time, the whole control process is divided into a limited period of time according to certain rules using the idea of ​​adaptive control, and the objective function is estimated with perturbation analysis Then, the optimal threshold in the process control problem is estimated by using the stochastic approximation algorithm based on the second derivative, so as to realize the adaptive threshold control. The simulation example is used to verify the convergence of the algorithm .