A vision-based planning method for robot arm of Chang´E-3 lunar rover

The planning method for robot arm probing is one of the key technologies in Chang´E-3 mission, which forms the basis of lunar scientific exploration. This paper presents a vision-based robotic planning method which is applied in the Chang´E-3 mission with two steps. First, the position information of the probing point in the working environment is obtained by matching the stereo images of the hazard cameras. Then, the moving path of the robot arm is calculated from the constraints of the surrounding terrain and target, which generates a safe and collision-avoiding motion path from an initial state to the target position. To validate the feasibility and accuracy of the method, a numerical simulation is presented, and an experiment is conducted. The experimental results show that the positioning error is superior to 2mm and the angular deviation of the normal vector is less than 0.5°. On January 14, 2014, Chang´E-3 lunar rover performed the probing test, successfully positioning the target and spreading the robot arm to the target position precisely.