Research On Trajectory Planning Of Biaxial Position Turntable Based On Second Order Sliding Mode Variable Structure Filter

Turntable is an important test and simuliation unit on the ground to test and demarcate performance of inertial sensitive components.It is widely used in calibration,reliability,acceptance identification tests of inertial sensitive components in the entire possess of their being designed,manufactured,used and maintained.Therefore,the research of high-performance turntable is of great scientific significance and practical value for the development of military aerospace,aviation,marine as well as numerous civilian areas.This thesis focuses on the point-to-point motion trajectory planning algorithm of a biaxial turntable.In order to study the trajectory planning algorithm of inertial navigation system,this paper introduces the mini test turntable and analyzes the points of motion trajectory planning.Three-phase AC synchronous servo motors is used to drive the biaxial turntable and worm-gear reducer is applied to coordinate the rotation speed difference between turntable and motors.Control system hardware is built by IPC and PCI interface card and control code is written in Windows XP operating system.Finally,the shortage of the existing point to point motion trajectory planning are analyzed,and the research direction of trajectory planning is pointed out.In the motion process,it is required that the biaxial turntable is smoothly moved without impact and meet certain speed,acceleration and torque constraints.For these requirements,in this thesis,path planning algorithm based on sliding mode variable structure filter is studied to optimize the trajectory of the biaxial turntable,on the premise of satisfied with the dynamics and kinematics constraints.Comparative analysis between two path planning algorithms with and without dynamic constraints is carried out by computer simulation and the results verify that the algorithm is effective.For the chattering problem of output track acceleration of trajectory planner in some cases and latency problems of switching control signal,this thesis propose appropriate solutions through in-depth research.By deviding the phase plane into two regins,i.e.,regin nearby phase plane origin where chattering occurs and the regin away phase plane origin where chattering does not occur.In the latter region,based on the nonlinear control strategies,phase trajectory characteristics is improved by boundary layer method.And In the former regin,new nonlinear control strategies is designed to eliminate chattering effect.Finally,the effects of this method is analyzed by simulations.Testing experienment of the biaxial turntable is carried out to test actual planning effect of path planning algorithm used in this thesis.Least Squares is used to identify the actual value of coulomb friction and viscous friction coefficient of Inner and outer shaft system of the biaxial turntable.In accordance with viscous friction and coulomb friction coefficient obtained above,corresponding inertia identification experiment is carried out,and the actual moment of inertia is calculated.In order to verify feasibility and superiority of the trajectory planning algorithm,path planning experiment of the biaxial turntable with T-type and S-type acceleration and deceleration,trajectory planning experiment of sliding mode variable structure filter,and the corresponding improved trajectory planning experiment by algorithm of region dividing are implemented.Comparative analysis among the three results is also disscussed.