Trajectory Tracking Control Strategy Research Of 6-DOF Manipulator

Multi-joint manipulator plays an increasingly important role in industrial production due to its advantages of high speed,high positioning accuracy,and flexibility.Because of the high nonlinearity and strong coupling of the manipulator structure,the research of high precision trajectory tracking control technology has always been a hot issue for scholars at home and abroad.This paper takes the six degree of freedom manipulator as an example,which is the widely used in industry,focusing on the issue of kinematics,dynamics and control strategy,which have a great influence on the track tracking precision of the system.First,in order to realize the programmability of the manipulator,based on the D-H pose description method,established the coordinate frames and determined corresponding structural parameters.The numerical model of the forward and inverse kinematics of the manipulator is solved.The trajectory planning of joint space and Cartesian space are carried out for the established manipulator model.The dynamic model of the manipulator is set up by Newton Euler recursive method,and the dynamic characteristics of the manipulator are discussed,which provides a theoretical basis for the design of the control algorithm based on the feedforward compensation.Then,Studied two kinds of control strategy of independent joints Linear control based on approximate assumption and nonlinear control based on dynamic model.Gravity compensation is introduced into speed loop of the independent joint servo control,which effectively reduces the vibration amplitude of the system,and introduced speed compensation into the position loop,solved the problem of system error caused by the position loop zero output.The fuzzy sliding mode control strategy proposed,Base on the traditional robust control.Designed single input and single output fuzzy logic to study the approaching term of sliding mode control,which not only guaranteed the real-time performance of the system,but also improved the limitations of the traditional algorithm,such as the limited adaptive ability,the oversize of the initial moment,the buffeting and so on.Finally,based on the TwinCAT3 software development platform,the application of the feedforward compensation nested PD control algorithm is implemented on the six degrees of freedom industrial manipulator with the ST programming language,and the trajectory tracking accuracy and system error are analyzed based on the experimental results of the platform.