Trajectory Tracking Control Of Multi-DOF Robot

With the industrial manipulator has been widely used in all walks of life,the control precision and the speed of the industrial manipulator has been put forward higher requirements.In this paper,the trajectory tracking control of industrial manipulator is used as the main research content,and the control method is improved to realize the real time tracking control of the end of the manipulator.Firstly,a basic coordinate is established for the 3-DOF spatial manipulator.The forward kinematics model is established according to the geometric relations of the manipulator in the three-dimensional space,and the inverse kinematics model is obtained by the analysis of the forward kinematics model.The dynamic model of the 3-DOF spatial manipulator is established by using the Lagrange function method.The verification of all control methods in this dissertation is based on this model.Using standard D-H parameter method establish the 6-DOF industrial manipulator Denso VP6242 G forward kinematics model.The inverse kinematics model is established by means of geometry method and Euler angle transformation method.The dynamic model of Denso VP6242 G is established by using the Lagrange function method.Secondly,the control method is studied based on the 3-DOF spatial manipulator model.The first control method is proposed in this paper: the improved sliding mode control based on PID control,in order to solve the chattering problem of the system,a new switching function is defined and introduced.It is proved that the control strategy is superior to the PID control and the traditional sliding mode control in the aspects of fast and chattering.It is found that the improved sliding mode control can't achieve high precision trajectory tracking under complex environment with the presence of parameter perturbation and external disturbance.Therefore,second control method is proposed for the above mentioned problems: a new type of sliding mode control based on extended state observer.In the case of various uncertain variables,it is found that the method is more robust.Because the extended state observer is introduced to estimate and compensate the unknown disturbance,the parameters of the system,the dynamic and the coupling parts of the system.So strictly speaking,the new control method is not dependent on accurate mathematical model of the controlled object.Finally,a novel sliding mode control method based on extended state observer is applied to 6-DOF manipulator Denso VP6242 G experimental platform.By comparing with the method of built-in the experimental platform(PID),it has obvious advantages in the fast and accurate tracking of the end of the manipulator.The chattering phenomenon of the manipulator is obviously weakened,and the servo motor in the joint is effectively protected.