The Research On The Trajectory Planning Method Of Manipulator Based On The Space Motion Base

With the human exploration of space, space robot technology arises at the historic moment,and has made great development. There may be variable speed running state, and the differencebetween the speed changes may be large when space robot performs tasks, and it embodies thecross-scale operation characteristics of space robot in speed. Based on the background ofcross-scale space base control, this paper studied the collaborative optimization problem of thetrajectory planning and the cross-scale phenomenon in speed among each subsystem of spacerobot system. The research content is as follows:First of all, kinematics model of the free floating space robot system under nonholonomicconstraint is established according to the basic knowledge of robotics and features of space robot,combined with the linear momentum and angular momentum conservation. Take the planartwo-connected rods space robot as an example, the nonholonomic characteristics andinterference characteristics of space robot are analyzed, and MATLAB simulation has beenapplied to the research. The working space concept and calculation method of planar connectingrod free floating space robot have been given.Secondly, the trajectory collaborative optimization based on the theory of the minimumenergy dissipation on space manipulator joints angle is studied, and the method of parametricpolynomial is adopted to approximate the free floating space robot’s trajectory. Switchmomentum conservation equations of the system from the joint space to low dimension space bycoordinate transformation due to the complexity of calculation in the joint space; According tothe theory of the minimum energy dissipation on manipulator joints angle, the objective functionis set. It appears the phenomenon of poor local search ability when using genetic algorithm tosolve the objective function, so chaos genetic algorithm is designed in order to solve thisproblem. In the low dimensional coordinates, using the system initial point and the target point,combined with chaos genetic algorithm to optimize the objective function, so as to determine thecoefficient of polynomial and achieve trajectory function in joint space through inversetransform. Set up the range constraint of the anti-trigonometric function, the maximum workingspace constraint of the end tongs, and range constraints of base subsystem attitude Angle to verify correctness for this model.Then, for the trajectory collaborative optimization problem of the speed cross-scale, twoexamples which have the greater difference within the moving range are used to make thesimulation research. When all test conditions are met, it suggests that the trajectory collaborativeoptimization of the base and two subsystems of mechanical arm can be completed at the sametime only through the trajectory optimization of the space manipulator’s subsystems. In bothcases, there have been the times the speed change phenomenon of the moving range relative tothe base subsystem and mechanical arm subsystem for the joint Angle.It reflects the variationcharacteristics of speed cross-scale in trajectory planning, and both subsystems complete thetrajectory collaborative planning smoothly at the last time.Finally, for interference and coupling properties between the space manipulator and spacebase, plan the trajectory for space robot system by designing trajectory planning tasks of themechanical arm subsystem as disturbance variables to make the disturbance of base the least andthe trajectory planning of mechanical arm is completed at the same time. The function relation ofthe base’s attitude Angle and each mechanical arm’s joint Angle in joint space is achievedthrough the analysis of the characteristics of the free floating space robot. Parameterize the jointAngle by making use of sine function, and establish function equation by taking the minimumbase disturbance as the objective. About90%characteristic of the optimum solution andprecocious phenomenon can be obtained by the genetic algorithm, and the adaptive geneticalgorithm is designed to have optimization-oriented operation. Through the analysis ofsimulation results, it shows that the base’s attitude changes can be the least only when the tasksof the mechanical arm are completed and the phenomenon of speed cross-scale appears at thesame time.