A stabilization system including a platform supported by two or more rotatably-coupled gimbal frames each having a pivot assembly disposed at its rotation axis to couple an actuator to a rotation sensor having a rotation-sensitive sensor axis that is fixedly disposed with respect to the rotation axis, and a controller including means for accepting the sensor signals and for producing each motor signal needed to dispose the platform in a predetermined angular position with respect to each rotation axis independent of changes in the base orientation. A motion simulator embodiment includes controller means for accepting an external slew signal sequence and means for producing the motor signals needed to move the platform along a predetermined sequence of positions represented by the slew signal sequence.