基于Serret-Frenet坐标系的翼伞系统轨迹跟踪控制

PATH-FOLLOWING OF PARAFOIL SYSTEM BASED ON SERRET-FRENET

基于翼伞系统归航轨迹的特点,采用Serret-Frenet坐标系表示距离“平衡”轨迹的偏差,得到线性时不变的误差运动方程.由此误差方程可以得到控制量与轨迹偏差之间的传递函数,直接进行轨迹控制器的设计.对于控制器输入所需的轨迹偏差和偏差率可以采用解析的方法近似求解,极大地简化了计算.整个设计流程简单明了,采用PD控制器进行轨迹跟踪的算例表明此套方法的有效性.

Based on the characters of parafoil homing trajectory, Serret-Frenet frame was used to describe the shortest distance from the current position to the trimming trajectory. Then, using the theory of small disturbance linearization, it showed that the error equations were time invariant. The transform function between the control and the position error could be found from those error equations, and could be used to design the trajectory controller directly. The position errors and velocity errors which are inputs to the trajectory controller could be solved by analytical method, which greatly simplify computation. The effectiveness was testified by the result of example.