介绍了为直流电机控制系统所设计的滑模控制器．原系统存在着由库仓摩擦力矩所导致的非线性．控制器根据常规的变结构系统进行设计，然后通过符号函数的替代来平滑不连续的控制法则，并用一种单位饱和函数来减少其抖动．最后推导出离散时间的控制法则．所提出的算法计算容易且有鲁棒性，已在以数字信号处理器DSP为基础的直流电机位置控制系统上得到实现，并显示出令人满意的结果。 The sliding mode controller designed for DC motor control system is introduced. The original system has the nonlinearity caused by the friction moment of warehouse. The controller is designed according to a conventional variable structure system and then smoothes discontinuous control laws by replacing symbolic functions with a unit saturation function to reduce its jitter. Finally, the control law of discrete time is deduced. The proposed algorithm is computationally easy and robust and has been implemented on a digital signal processor DSP-based DC motor position control system and shows satisfactory results.