6-DOF Manipulator Trajectory Planning Methods Research

Manipulator trajectory planning plays an important role in the manipulator control system. It aims at planning displacement, velocity and acceleration of manipulator trajectory during exercise through setting goals accordingly: to improve the stability of the robot arm motion smoothing and reduce the impact of vibration during exercise, to improve its work efficiency and reliability during the experiment. In this thesis,six degrees of freedom manipulator laboratory for the study its forward kinematics, inverse kinematics and trajectory planning method and based on joint space are studied.Firstly, The characteristics and shortcomings of current manipulator planning methods are presented. The kinematics analysis mainly includes those of the kinematics and inverse kinematics. 6-DOF manipulator-REBot-V-6R-650 of the laboratory as the research object. A model of the manipulator is produced by Robotics Toolbox of MATLAB,which provides a foundation for the trajectory planning following.And use the positive and inverse kinematics to verify the correctness of the model.Secondly,three methods of trajectory planning based on joint space are analyzed: five sections cubic polynomial interpolation trajectory planning algorithm, 3-5-3 polynomial interpolation trajectory planning algorithm, and 4-3-4 polynomial interpolation trajectory planning algorithm. The results of simulation turn out that five sections cubic polynomial interpolation trajectory planning algorithm can make the trajectory smoothly, but needs large amount of calculation; 3-5-3trajectory planning algorithm does not need large amount of calculation, but can't achieve a smooth trajectory; 4-3-4 trajectory planning algorithm can also need small amount of calculation and achieves a smooth trajectory. Thus this thesis chooses the 4-3-4 polynomial interpolation trajectory planning algorithm to do the trajectory planning of 6-DOF manipulator in joint space, then do the simulation experiment in the MATLAB.Thirdly, joint space of time based on particle swarm optimization method is proposed based on the 4-3-4 polynomial interpolation trajectory planning algorithm, considering the characteristics that the parameters of particle swarm is easy to adjust and the algorithm structural is simple. To narrow the search and avoid steps from the independent and dependent variables mapped in the structure of particle swarm algorithm to calculate the process, the target space in the optimization search is selected directly, thereby reducing the search dimension and simplifying the calculation. Through using algorithms optimized six degrees of freedom manipulator trajectory planning,the advantages of the method are verified on the running time and running smoothly degrees.Finally, In order to visually compare the trajectory curve before and after optimization,Establish comparative simulation control in the MATLAB. Worth to trace the curve before and after optimization by entering the parameters. experiment of outline ways running trajectory is performed on the 6 DOF manipulator experiment platform of the laboratory. It demonstrates rationality of trajectory planning scheme through stable running of manipulator trajectory during the experiment.