Super-low-speed high-precision servo system for enabling antenna to track space object continuously

MAPS (modular antenna pointing system) is a super-low-speed high-precision servo system used by explorer platform satellite to maintain continuous digital communication with TDRS (tracking and data relay satellite). The super-low-speed servo system we designed is about the same as MAPS in super low speed but is an order of magnitude better than MAPS in tracking precision. First we analyzed theoretically direct torque control of slotless brushless sinusoidal torque motor, which contains an rare earth permanent magnet external rotor. In designing the servo system, after repeated rethinking, we finally decided on using direct-driving-type driving circuit, which, in our opinion, is key to attaining high precision. In order to ensure the reliability of the servo system, we used a MOSFET switch in circuit breaker. Feedback channel is the key channel of the servo system. In our design, we paid special attention to processing detected position signals in the feedback channel so as to convert them into digital signals of high precision. Test results of the servo system designed and developed by us show preliminarily that it is of high precision (±0.05°) and excellent super low speed stability.