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Air spindle attitude control via proof mass actuators

Attitude control of a single-axis air spindle testbed using two proof mass actuators is studied by means of analytical models and laboratory experiments. A key feature of the air spindle testbed is that ideally there is no external moment; hence the total angular momentum can be assumed to be conserved. After a brief hardware description of the air spindle testbed and proof mass actuators, the equations of motion are derived, assuming the total angular momentum is zero. It is shown that arbitrary platform reorientation can be achieved using periodic proof mass motions. Two proof mass actuator control strategies are constructed based on piecewise constant motions and sinusoidal motions. Experimental results are summarized and are compared with simulation results.