ardurover开发：添加新的模式和导航算法 Ardupilot+Pixhawk+Jetson TX2

rover的控制方式：

1. the L1 controller converts an origin and destination (each expressed as a latitude, longitude) into a lateral acceleration to make the vehicle travel along the path from the origin to the destination. This lateral acceleration is then passed into the steering controller.
   先根据目标点和初始点生成转向速度
2. the steering controller can convert a desired lateral acceleration, a angle error or a desired turn rate into a steering output command (expressed as a number in the range -4500 to +4500) that should be fed into the motor library (see AR_MotorsUGV.h)
   转向控制器能够吧一个期望的侧向加速，角度偏差和期望的转向速度转换成输出的指令，范围子啊-4500～4500之间的数值，
3. the throttle controller can convert a desired speed into a throttle command (expressed as a number from -100 to +100) that should be fed into the motor libra