三轮移动机器人具有稳定性好、结构简单等优点被广泛应用于工业和机器人竞赛等领域.因为机器人的两个主动轮的尺寸、驱动电机、减速机构以及驱动电路等存在差异,造成了在直线移动时发生偏移的现象.针对这一情况,该文提出了使用数字PID控制器来控制机器人的直线行进,经过多次试验选取了合适的参数,实现了三轮移动机器人的直线行进.“,”The three-wheeled mobile robot have preferably stability and simply structure, so it is widely applied in the industry and robot contest. However, there are some difference about the robot's drivers, motors, speed-down machines and driving circuits, the offset occur in moving along ideal straight line. In this paper, the digital PID controller was designed to control the robot linear motion. By many examination, the appropriate parameter was chosen. The last, The three-wheeled mobile robot can travel accurately along straight line.