Research On The Space Minitype And High Precision Servo Turntable

Along with the development of the worldwide national space technology, to utilize and control the space has become a commanding height so that every military power takes efforts to preempt it. As an important carrier of the space vehicle in detecting and tarcking target, the servo turntable is playing an increasingly important role. At present, the space electric servo turntables are mostly driven by the brushless dc motor and measured by the rotating transformer, however, due to the disadvantages of the both components, the servo turntables still have many problems. In view of the above problems, this paper develops an ac servo turntable which based on the PMSM(permanent magnet synchronous motor) and magnetic encoder, to make it adapt to the space requirements better.Firstly, based on the space servo turntable’s requirements in miniaturization and high precision, this paper designs the overall mechanical structure of the turntable. According to the load and size requirements of the turntable, this paper selects its structure formreasonably, and designs the double motor gear transmission scheme to eliminate the back lash problem which exists in the process of gear transmission, this scheme improves the stationarity of the turntable transmission. In addition, in view of the high precision requirement, this paper designs the three magnet circles combined structure of the magnet encoder, and verifys its feasibility through the simulation of electromagnetic analysis by the JMAG-Designer software.Secondly, this paper detailed designs the turntable’s PMSM and makes the simulation analysis. The structure design of the PMSM including the choice of the rotor form, the determination of the slots and poles, the design of the windingturns and wire diameter, and the material selection, finally the motor’s miniaturization design meets the requirements of the turntable techniques. And then, the electromagnetic simulation analysis is carried out on the motor model using the JMAG software,the data such as back electromotive force, torque ripple, flux density, iron loss are obtained from the simulation to prove the rationality of the PMSM’s design.Thirdly,this paper has carried on the hardware design of the turntable servo system controller. For the design of turntable’s double motor driving chain structure, this paper determines the double motor controlling design scheme of the motor controller, and detailed describs the main controller schematic diagram in aspect ofthe circuit of main and slaveCPU, the power drive part, the feedback part and the power supply part; For the design of the magnetic encoder’s three magnet circles combined signal mechanism, this paper designs its single-pole magnetic hall board and multi-poles magnetic hall board.Finally, in this paper,the software program of the turntable system is developed, and the related experimentsare made to test the whole system.On the one hand, this paper further improvesthe magnetic encoder’s program for calibration and working, and trough the alternative test proves the precision of the magnetic encoder can meet the requirement of the turntable. On the other hand, for the design of turntable’s double motor driving chain structure and the double motor controllerscheme, this paper brings up the control strategy and develops the control program.On the basis of debugging the motor’s current loop andspeed loop, this paper makes the experiments to verify the feasibility of double motor control strategy.