Research On Modeling And Control Of Ping-Pang Playing Manipulators

As an important part of Ping-Pang robots,Ping-Pang playing manipulator is a member of robotics research fields,having a wide range of significance.The research object is Ping-Pang playing manipulator,and the research content are the building of Ping-Pang playing manipulator's mathematical model,the control of the positioning and trajectory and other problems.In this thesis,the control problem of the trajectory curve of Ping-Pang playing manipulator's end is analyzed,and the coordination and smoothness during moving and other problems are discussed.In this thesis,the model of the Ping-Pang playing manipulator is built by D-H representation method,including the building of coordinate systems and the transformations between coordinate systems and other related steps.Next,the positive kinematics equations are obtained.By matrix transformation and other mathematical theories,the inverse kinematics equations are deduced.In these inverse kinematics equations,the joint angles are represented by their trigonometric functions.Hence,these inverse kinematics equations are processed by the idea of classification.On this basis,the positioning and trajectory planning are studied.Meanwhile,the realization steps of algorithms are obtained,and the correctness of algorithms is verified by experiments.Positioning includes two cases:the first one,let the end of Ping-Pang playing manipulator reach the specified position,with only the position information of the end;the second one,let the end reach the specified position and maintain the desired posture,with both the position and posture information of the end.As the inverse kinematics equations contain the posture information,they can solve the second positioning problem directly.In the first positioning problem,this thesis does relevant processing for the posture.The requirement of positioning is only to reach the target point from the initial point,not to care about the track problem.In the trajectory planning problem,there are two requirements,which are to plan trajectory autonomously and to make the end move along the specified trajectory.In this thesis,the single polynomial algorithm is used to realize the requirement of planning trajectory autonomously.The meaning of planning trajectory autonomously is that the Ping-Pang playing manipulator can itself calculate the end's position each moment.Then,to control the general direction of the trajectory,the problem about the trajectory planning including the specified intermediate points is proposed,and this process is realized by algorithms such as polynomial interpolation.After that,with the features of polynomial interpolation algorithm,the requirement of moving along the specified trajectory is realized.Moreover,two problems of moving along the straight line and the circle are discussed.In this thesis,the physical experiments of the two cases of positioning are respectively carried out to verify the algorithms' correctness.For the experiment of trajectory planning,because of the higher requirements for the steering gears,the tool software Matlab is adopted to build simulation platform and for the processing and analysis of experimental data.By use of SimMechanics toolbox of Simulink,the virtual mechanical structure of the Ping-Pang playing manipulator is constructed,which intuitively reflects its moving process,and the track graphs of the end are drawn.Consequently,it is easy to analyze the algorithms for us.By drawing the curve graphs of the angle and angular velocity and angular acceleration of each joint,analyze the smoothness and coordination,and compare various algorithms.