说明：  单级倒立摆的稳定控制，实际上是一单输入多输出系统的稳定控制。此时系统输入是电机控制电压u，输出是倒立摆竖直方向角度 和旋臂位置 。对方程(2.5)进行变形即得 与u 之间的输入输出方程,很明显,它是一个不稳定的二阶系统
(Single inverted pendulum stability control, is actually a single-input multiple-output system stability control. At this point the system is a motor control input voltage u, the output is inverted pendulum angle and vertical position of spiral arms. Of the equation (2.5) for deformation of the gain and input-output equation between u, obviously, it is an unstable second-order system)