Design And Realization Of Three-Axis Turntable Control Based On Virtual Axis

As the key equipment of simulation and test in aviation field,turntable is a significant factor in the research process of aerial vehicles.It's advantages include small volume,high specific rigidity,large load handling capability and perfect dynamic property.It can realize different space attitudes based on motional parameter set and simulate all kinds of attitudes and motions in a laboratory environment,which can conduct expected testing on the components under load and provide reliable testing date for product design and examination.Parallel mechanism has been used extensively in the fields of robots,machine tools,motion simulators etc.The thesis takes 3-UPS/S serial and parallel mechanism for turntable design,which not only makes into play the advantages of parallel mechanism,but also uses the large space of serial mechanism.The work in this thesis includes:(1)Based on the introduction and analysis of parallel mechanism and its application in motion simulator,the thesis designed the overall turntable system.(2)Built up the mathematical model of the speed and acceleration of all branch chains based on inverse kinematics.(3)With the kinematic analysis,the dynamical model was established by Newton-Eulcer method and the power of the actuator was calculated.(4)The hardware system was established according to the control requests.AC servomotor with photoelectric encoder as the feedback components worked as the driver of the turntable's 4 servo axises.Friction screw was used to enhance the accuracy of the system.(5)With respect to the control software,it mainly includes:trajectory planning for the parallel turntable by S type speed curve,design of the position control with the strategy of virtual axis rough interpolation and real axis fine interpolation,formulation of the remote control process by CAN Field-bus,zeroing method,tuning of PID parameters etc.(6)Finally the thesis introduced the parallel platform position accuracy test,as well as simulation analysis of the rate precision and bandwidth,the results show that it meets all requirements.The turntable has already been in practical application.