A novel omni-directional perturbation platform

The study of human, upright-balance is often performed by perturbing a base on which a subject is standing. Once a perturbation is initiated, data describing a subject's ability to balance is recorded and analyzed. We introduce a novel perturbation device that can translate and rotate its base in any direction within a 2D plane. This robust perturbation envelope will expand researchers' abilities in the study of upright balance and balance recovery. The heart of the design is the use of four powered casters as the platform's transmission system. The casters' offset insures that the Jacobian matrix describing the system's planar motion is non-singular. A rapid embedded programming method is used to develop the control system. By controlling the orientation and speed of each caster, translation, rotation, or combined perturbations can be easily implemented.