Research On Dynamics Modeling And Trajectory Planning Of Special 6-DOF Mechanism

The model supported special 6-DOF mechanism is the key equipment to complete a special test,in this paper,the kinematics,dynamics and trajectory planning of the6-DOF mechanism are researched.In order to improve the efficiency of the test,the time optimal trajectory of the mechanism is solved by genetic algorithm under the constraints of kinematics and dynamics.First of all,based on demand and function analysis,a set of 6-DOF mechanism in series is researched,which has a good structure and meets the requirements of various technical indexes.On the basis of this mechanism the following research is carried out,the kinematics model of the mechanism is established by D-H method,and the forward/inverse kinematics of the mechanism is solved,the correctness of the results is verified by software programming.Next,the Newton-Euler iterative algorithm is used to study the dynamics of the mechanism,which is convenient in program operation and more convenient to construct dynamics constraints in the subsequent optimization solution.According to the constructed algorithm,the inverse dynamics solution of the mechanism is obtained by MATLAB programming,and the correctness of the results is verified by comparison in the simulation analysis of the Adams.Through the dynamics study of the mechanism,the mechanical properties of the mechanism can be better played on the premise of meeting the task requirements.Moreover,the trajectory planning of the mechanism in cartesian space and joint space is studied,the appropriate planning method is chosen to meet different practical requirements.According to the planning algorithm,MATLAB programming is used to verify the effects of different methods on the trajectory planning of the mechanism,the planned trajectory curve has good continuity and smoothness,which proves the effectiveness of the trajectory planning method applied in the mechanism.Through the study of the trajectory planning of the mechanism,it makes the mechanism to complete the test task more efficiently,and further completes the trajectory optimization on this basis.Finally,since the dynamics constraints were not considered in the previous trajectory planning,and the trajectory planned was not the optimal time,to solve this problem,a trajectory optimization with the shortest time as the optimization objective is proposed.The kinematics constraint is constructed by cubic spline interpolation method,the dynamics constraint is constructed by Newton-Euler iteration method,and the optimized mathematical model is solved by genetic algorithm.Genetic algorithm toolbox for simulation calculation,the shortest time for optimal trajectory is obtained.Through the optimal trajectory curve,it is proved that the results satisfy the constraint conditions,and the optimal solution gives full play to the performance of the mechanism.The simulation results verify the correctness and practicability of the trajectory optimization algorithm.