The Research On Path Planning Method Of Free-floating Space Robot

With the increasing pace of space exploration, space technology has achieved rapidgrowth. Space robot is an important aspect of space technology, and is a focus of researchin the world. The free-floating space robot(FFSR) is one kind of space robots, and the baseof space robot system is out of control at work, and it saves fuel which is very importantfor the space robot in this working mode. In this paper, we took free-floating space robotas example, studied the path planning problem of free-floating space robot, aimed to makethe system use the least amount of energy.Firstly, introduced the concept and background knowledge of space robot, andintroduced the development status and achievements of space robot at home and abroad,then introduced the methods on dynamic modeling and path planning of space robot.Free-floating space robot system is constrained by the conservation of angular momentum,and the conservation of angular momentum is an nonholonomic constraint. According tothe angular momentum conversation of free-floating space robot, the kinetic equation anddynamic equation were derived, and the corresponding kinetic characteristic and workspace were described.Secondly, the planar2-link free-floating space robot was taken as an example, and thepath of free-floating space robot was planned according to the minimum use of energy, tomake the space robot system complete the planning task with the minimum use of energy.Based on analyzing of free-floating space robot’s dynamic equation, the system wasdescribed by the parameterized joint angle trajectories, and the momentum equation wastransformed from the joint angle space to a new and lower dimensional space, then themodel of the system was improved, combining to the minimum use of energy, the pathplanning problem was transformed to an optimization problem, then the optimizationproblem was solved by using self-adaptive particle swarm optimization(SAPSO). Weknew that the stability of the space robot system was enhanced by using the improvedmodel. The best fitness value was obtained more faster and more accurate by usingSAPSO to solve the optimization problem, so it was known that SAPSO was more suitablefor solving this kind of optimization problems.Lastly, in order to save the energy of free-floating space robot system at work, thedriving torque of joint angles was taken as optimization objective, the path planning wasstudied to save the energy. According to the momentum equation, the joint angles wereparameterized, the path planning problem was designed by taking the driving torque ofjoint angles as optimization objective, and the path planning problem was transformed toan optimization problem, then the optimization problem was solved by using chaotic localsearch particle swarm optimization(CLSPSO), so the path planning task was completedand the optimal torque was achieved. According to the simulation results, the best fitness value could be obtained more faster, and the obtained fitness value was more accurate byusing CLSPSO, so we knew that CLSPSO was more suitable for this kind of optimizationproblems.