Study On Servo System Of Tracking Radar Antenna

Servo system is a main part of tracking radar. The accuracy in servo system directlyaffects the tracking precision of radar. With continuous development of power electronicstechnology, sensor technology and motor control theory, and with constant progress ofhigh-performance digital signal processor technology, the radar servo drive equipment ischanging from DC to AC, and the servo control system is changing from analog to digitalsystem. The advanced control theory has been applied to servo system. All these have laid thefoundation for development of high-performance radar servo system.During mechanical scanning radar tracking target, the elevation motor and azimuthmotor is used to control radar antenna turning, adjust the antenna to point at target. As theprinciple of elevation motor and azimuth motor is similar, the azimuth servo control system ismainly studied in the thesis. The brushless DC motor is used as driving motor in the thesis,the model of servo system is established according to the radar antenna servo system, thedesign approach of radar three closed loop servo system is studied, and the performance of theradar control algorithm is mainly analyzed in the way of guiding work mode. The frequencyresponse curve of three-loop is drawn, and the position and speed response curve is giventhrough simulation. Results show that, the three loop servo system designed with seriescorrection approaches is stable. The traditional PID controller parameters is adjusted in thesystem parameter perturbation and external interference, and the sliding variable structurecontroller insensitive to the parameter perturbation and external interference, so slidingvariable structure control is adopted in the position loop. Through the analysis, slidingvariable structure control exists a certain chattering. Neural network can approach the linearor nonlinear system. The combining method of neural network and sliding variable structurecontrol is applied to inhibit the chattering. The simulation results shows that the neural slidingmode variable structure controller has the advantage of the general sliding mode variablestructure control, meanwhile, it has a good performance for reducing chattering.The hardware mainly includes control circuit which based on TMS320F2812and motordrive circuit. The controller is mainly used to realize control operation, data process and A/Dprocess. MOSFET is used to build full bridge inverter circuit in the drive circuit that mainlyrealizes isolation, inverter, and driving function. The main circuit schematic diagram and thesoftware designing process is given. Experimental results show that the control circuit anddrive circuit can realize the control of brushless DC motor servo system.