Spherical linkage and force feedback controls

A user interface system comprising:

• a plurality of linkages connected between a platform and a base, the linkages connected to constrain motion of the platform over at least a portion of a spherical surface;
• a support assembly comprising a spherical joint having a centre of rotation substantially concentric with the spherical surface, the spherical joint acting to constrain motion of the platform to the portion of the spherical surface;
• and
• a plurality of sensors coupled to detect motion of the platform over the portion of the spherical surface;
• wherein the plurality of sensors comprises at least one sensor corresponding to each of the plurality of linkages, the at least one sensor coupled to sense movement of its corresponding linkage in response to motion of the platform;
• and
• wherein the plurality of linkages comprises three linkages, each of the three linkages comprising:
• a primary link pivotally coupled to the platform via a primary pivot joint;
• and a secondary link pivotally coupled to a mount that extends from the base via a secondary pivot joint and pivotally coupled to the primary link via an intermediate pivot joint.