Conventional training simulators commonly use the hexapod configuration to provide motion cues. While widely used, studies have shown that hexapods are incapable of producing the range of motion required to achieve high fidelity simulation required in many applications. Atlas is a six degree of freedom vehicle operating training simulator motion platform where orienting is decoupled from positioning, and unbounded rotation is possible about any axis. Angular displacements are achieved by manipulating the cockpit contained in a 2.9 metre (9.5 foot) diameter sphere with three Mecanum wheel actuators. The angular velocity Jacobian, J(omega), maps the desired angular velocity of the sphere to the required speeds of the three Mecanum wheels, while the static force Jacobian, J(iota), maps the static moment vector required to statically orient the sphere to the static torques required by the three Mecanum wheels. In this paper, the two Jacobians are derived independently, and it is confirmed that J(omega) = J(iota)(T), as it must. The implications on the required normal forces at the interface between the sphere and three Mecanum wheel contact patches are discussed.
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