Abstract: The stress on the rotary arm， in the mining system with rotating arm and landing leg， is complex and changeable. Analysis on the stress by the traditional dynamics usually leads to huge workload and complex equations with inconvenient solution or even non-solution. It is unavailable to make numerical solution in computer. Therefore， aiming at the joint dynamic characteristics of the rotating arm in mining system， the Kane method is used to establish the dynamics model for the attitude adjustment of the rotary arm. On this basis， the genetic annealing algorithm is adopted to plan the movement of the rotating arm so as to make the joint torque minimal and the attitude adjustment of mining more smooth and steady. It provides positive theoretical significance to develop this new type of mining system and precisely control the rotating arm in seawater.

Key words: Deep-sea mining, Genetic annealing algorithm, Joint motion planning, Kane method