Development Of The Single-axis Turntable On Rotational Position Precise Control

Turntable equipment plays an important role in aerospace, the single-axisturntable is a device which provides a high precise standard location for tilt sensors.By analyzing the technical indicators of single-axis position control turntable, thepaper gives overall design of turntable’s electrical control part and the system blockdiagram, and the diagram divides the turntable system into two parts: setting partand servo part.Setting part uses to set the target angular position of the turntable throughsetting part, the setting amount transform to pulses to control a servo motor. Systemsettings part gives the specific hardware and software design, and uses amicrocontroller to virtual servo part and to achieve debugging.The results show thatthe setting part is designed to meet mission requirements.Through comparative analysis of commonly used control methods, theturntable selects compound control finally. According to the brushless DC motordrive characteristics, it uses strategy of the feedforward control and current loop,velocity loop and position loop "three-ring" closed-loop control. This paperestablishes a mathematical model of a brushless DC motor, and eventually gives the"three-ring" closed-loop control model, and on "no overshoot and no positionsudden change" principle, through "three-ring" closed-loop control model simulinksimulation, use trial and error method to get the system control parameters."three-ring" closed-loop control model shows that single-axis turntable is an IIsystem, if the system is stability for setting a higher position loop gain,then understep, ramp and acceleration signal, the steady-state error can be controlled withinthe allowable. Use the tuning control parameters in the model to get the systemback to the open-loop transfer function, and the bode plot shows that it is a highstability system.Based on the invariance principle, joins speed feed-forward loop, the resultshows it does not affect system stability but it improves the system dynamicresponse. In addition, the simulation tuning control parameters can be used as areference when debugging the servo part, in the end gives a brief introduction of theturntable calibration equipment.