Design And Control Of 6-DOF Parallel Motion Platform For Tank Fire Control System

The stability accuracy of tank fire control system is an important indicator in the comprehensive performance evaluation of tank,which is represented the tank’s ability to execute accurate strikes on targets.The 6-DOF parallel motion platform,with the advantages of high motion accuracy,strong load-bearing capacity and simple structure,is used for the testing means of the stability accuracy in tank fire control system.Installing the relevant sensing elements of tank fire control system on the 6-DOF parallel motion platform for debugging could be effectively reduced the test cost and test cycle.Taken the 6-DOF parallel motion platform of tank fire control system as the research object,the platform from several aspects was analyzed and the simulation model was established,and the overall design of the platform and control strategy research were completed on this basis.(1)The overall structure of the 6-DOF parallel motion platform was described,and the spatial coordinate system of the upper and lower platform was established.The mapping relationship of the spatial coordinate system of the upper and lower platform was established by using the chi-square coordinate transformation matrix,the inverse equations of the upper platform were calculated,and then the inverse solutions of velocity and acceleration were solved.The dynamics of the platform was calculated by using the Lagrang dynamics equations,and the structural design of the platform was completed based on the results of the above theoretical analysis.(2)According to the designed 6-DOF parallel motion platform structure,the platform system simulation model was built in Matlab/Simulink environment.The functions of the important modules of the platform simulation system was analyzed,including the rod length calculation module,PID control module and actuator module,and then static verification and dynamic simulation of the platform simulation system were conducted,it proved that the platform simulation system had accuracy and stability and could met the requirements of fire control system testing.(3)The factors affecting the fire control system was analyzed,and the structure of the road spectrum,the road power spectral density and the road classification criteria were analyzed.The modeling of the road spectrum was completed in the Simulink environment based on the white noise method.The road spectrum was inputted as an influencing factor into the platform simulation system and the motion characteristics of the platform simulation system under the action of the road spectrum was analyzed,including the tank driving at different speeds under the excitation of the same level of road spectrum and the tank driving at different speeds under the excitation of different levels of road spectrum,it was concluded that the higher the road spectrum level and the faster the travel speed,the more the position of the upper platform fixing point(actual artillery axis)fluctuated.(4)The control scheme of the 6-DOF parallel motion platform was analyzed,the two control methods of conventional PID control and fuzzy PID control were compared and analyzed,the corresponding fuzzy PID controller was designed based on the platform system.Fuzzy PID controller simulation model was constructed which was added into the 6-DOF parallel motion platform system.Compared the results of fuzzy PID controller with conventional PID control,the results showed that the fluctuation range of the fixed point coordinates of the upper platform was reduced under the action of the fuzzy PID controller,and the rod length variation curve of the platform system was smoother,it was verified that the fuzzy PID control strategy has higher stability.By the above theoretical analysis and simulation on the 6-DOF parallel motion platform,the design and control of the 6-DOF parallel motion platform for tank fire control system was completed,which is provided theoretical reference for the design and control of the 6-DOF parallel motion platform for practical application in tank fire control system accuracy detection.