Research On Trajectory Tracking Control Of Foldable 6-DOF Modular Tandem Orthpgonal Manipulator

As one of the main components in the field of robotics,the manipulator has the advantages of flexible movement,high positioning accuracy and low delay.The existing manipulator is mostly composed of joints in series or parallel connection of different design forms(size,shape,material),and the overall structure of the manipulator is complex,the versatility is poor,and the cost of parts replacement is greatly increased.In this paper,a foldable 6-DOF modular series orthogonal manipulator is designed,and the effective trajectory planning and trajectory tracking of the manipulator are realized.The specific research content is as follows:Firstly,the structure of 6-DOF modular series orthogonal manipulator is designed,and a three-dimensional simulation model of the manipulator is established.In order to realize the kinematics and dynamic modeling of the manipulator,the position and pose of rigid bodies in space,as well as the coordinate transformation between coordinate systems,were analyzed.The relationship between motion,force and moment is further studied,and the physical parameters such as speed,angular velocity,force,and inertia tensor of the connecting rod are analyzed,which provides a theoretical basis for dynamic analysis.Design the model scheme from the structural style,working mode and degree of freedom of the manipulator,and complete the three-dimensional modeling of the manipulator through SOLIDWORKS;According to the working object of the end effector of the manipulator,the joint quality,external dimensions,connection methods and other parameters of the manipulator are given,and the protective shell is designed for the servo based on the external dimensions.Secondly,aiming at the problem that genetic algorithms are prone to fall into local optimization,an improved multi-population genetic algorithm is proposed to solve the inverse kinematics.The D-H method is used to construct the positive kinematics model of the manipulator,and the transformation relationship between the joint coordinates is obtained,and the positive kinematics equation is derived.Aiming at the unstable convergence speed and long operation time of traditional multi-population genetic algorithm,the improved multi-population genetic algorithm is used to solve the inverse kinematics of the manipulator.The MATLAB simulation model of the manipulator was constructed,the forward and reverse kinematics analysis was carried out,and the five-order polynomial interpolation method was used for trajectory planning.The simulation results show that the proposed algorithm can adjust the parameters and select the appropriate search efficiency according to the actual situation while ensuring the high accuracy of the manipulator’s posture,and obtain better inverse solution and trajectory planning results.Then,the dynamic model of the manipulator is established based on Newton’s Euler method,and the fuzzy PD controller is used to carry out the trajectory tracking control of the manipulator.The three-dimensional model of the manipulator is imported into Simulink,and the manipulator control system is built in Simulink,and the fuzzy PD controller is further used to simulate and verify the trajectory tracking of the manipulator.The simulation results show that even under the condition of noise interference,the designed 6-DOF modular series orthogonal manipulator can still complete the trajectory tracking control well.Finally,in order to verify the effectiveness of the trajectory planning of the manipulator,an experimental platform for the manipulator is built.Design a two-layer distributed structure of the decision-making layer and the execution layer,the decision-making layer generates the trajectory,and the execution layer controls the rotation of the servo.First,the design of the manipulator control system of the fixed platform is carried out,and because the execution space range of the manipulator arm of the fixed platform is limited,the manipulator operation task of autonomous mobile arm cannot be realized,and the robotic arm system of the autonomous mobile platform integrating SLAM(Simultaneous Localization and Mapping),A* and Dynamic Window Approach(DWA)path planning is further designed.Experiments show that the robotic arm can autonomously move the grasping object to the specified position,which verifies the effectiveness of trajectory planning.