Kinematics Research And Trajectory Tracking Control Of Robotic Manipulator

With the development of control and related technologies,robotic manipulators have been widely used in various fields,such as medical and manufacturing,etc.,which provides a theoretical and practical basis for the realization of automatic nondestructive testing.The object studied in this paper is a six degree-of-freedom serial manipulator.The kinematics and dynamics of the manipulator is established firstly,and the desired space trajectory of the manipulator is tracked by designing the corresponding control method.As the basis of the trajectory tracking control of the manipulator,the kinematics realizes the mutual conversion between pose(including position and orientation)of end-effector in operational space and joint angles in joint space.Besides,this paper establishes the forward kinematics through DH rules,and the inverse kinematics is realized by algebraic method.In order to obtain the relationship between force and motion,this paper uses Newton-Euler method to establish dynamic model of robotic manipulator.Considering that the manipulator system is a complex nonlinear model,the precise control of the manipulator becomes a difficult problem due to modeling mismatch and external disturbances.Focusing on these problems,this paper uses the speed,stability and accuracy of the control response as a reference standard.Three control methods have been studied and designed based on sliding mode control and its advantages of anti-interference ability.Firstly,the nonsingular terminal sliding mode control method is used to realize the trajectory tracking of the manipulator.The sliding mode surface can steer the system state converge to equilibrium point within a limited time,which improves the accuracy of control.At the same time,by designing the dynamic equation of the tracking error,the discontinuity of the control signal caused by the switching control is eliminated,and the stability of the control is improved.In order to improve the response speed of the above control method,then the adaptive nonsingular fast terminal sliding mode control method is used to track the desired trajectory,which can drive the system state converge to the equilibrium point more quickly after the state reaches the sliding surface.In addition,the upper bound of system uncertainty is estimated through the adaptive law without prior knowledge,which improves the robustness of the control system.Finally,based on the characteristics of fractional order sign function at zero point switching,it is introduced into the design of reaching law of sliding mode control,which can improve the response speed of the control system.By adjusting different fractional orders,different reaching speed is realized,and the method extends the performance adjustment range of the switching control law.In the end,the paper uses the established kinematics to realize the spatial trajectory tracking of the industrial robotic manipulator.The kinematic solution selection and trajectory planning in actual control are studied subsequently.According to the overall structure and control flow of the industrial manipulator,the joint drive manner and the motion control based on the PMAC are studied.Finally,the tracking of desired trajectory of the industrial manipulator is achieved through MATLAB.