| Large-diameter antenna is used to carry out astronomy study and deep spaceexploration, it plays an important role. As the development of deep space exploration,advanced large-diameter antenna can meet the observation needs. The object research ofthis subject is a new dual-reflector antenna sub-reflector surface parallel institutionscontrol systemThe six DOF parallel platform has advantages of high precision,high rigidity, highstability, it has been used in large reflector antenna sub-reflector surface relative positionand orientation adjustment applications. It is more than one degree of freedom,multivariate and highly nonlinear coupled complex system, its performance is directlyrelated to sub-reflector surface controlling performance，parallel platform motion controlmethod is the key to improve the performance of sub-reflector surface.Firstly, this paper introduces composed of antenna sub-reflector surface parallelinstitutions control system. Then it establishes a mathematical model for six degrees offreedom Stewart platform, analyses the inverse dynamics and the inverse positionalgorithm of the parallel platform, researches spatial trajectory planning. The ministry intothe parallel mechanism of the control system establishes the theoretical basis.Secondly, the mathematical model of the single-axis drive mechanism, combinedwith the controlled object variable coupled non-linear characteristics of multi-parameteranalysis, the traditional PID control and fuzzy sliding mode control method is introducedto the system control. In this hybrid control system, sliding mode control is used toovercome the impact of model imprecision and disturbances, and fuzzy control uses toeliminate chattering, so it give full play to the advantages of both control method. TheMATLAB simulation experimental results show that the design of the proposed systemhas good control effect.Finally, this paper introduces the design of hardware and software for the controlsystem. In the attitude adjustment system of the sub-reflecting surface parallel platform,power system uses servo motor to drive the ball screw, achieves telescopic control of the axis. Servo motor connects the ball screws by reducer, because the reducer can increasethe torque and only pass in one direction, it slow down the speed of the servo motor andamplify the output torque of the motor, so it can satisfy the system requirements for lowspeed and high torque request. At the same time, it can eliminate the effect of platformweight to the platform attitude and reduce the difficulty of control. |
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