Parallel mechanisms are known to possess several advantages over serial architectures. When properly designed, parallel mechanisms can provide high stiffness, high bandwidth and excellent load carrying capacity. However, they typically suffer from a limited workspace due to their geometric arrangement in which several kinematic chains are connected to a common platform. Therefore, parallel mechanisms are generally built 'around' their workspace and are rather bulky.

In flight simulators, for instance, the Gough-Stewart platform is mostly used. This architecture is very effective and its application to motion simulation is mature. When larger translational workspaces are needed, the mechanism can simply be scaled up, leading to a larger device. However, scaling up the mechanism does not change the orientational workspace. Increasing the rotational workspace while avoiding singularities and joint limits is a difficult and challenging task.

In this presentation, the design of parallel mechanisms with large orientational workspaces will be discussed. It will be shown that kinematic redundancy can be exploited in order to enlarge rotational workspaces while preserving the parallel nature of the mechanisms. Planar mechanisms will first be addressed in order to introduce the concept. Then, spatial mechanisms will be considered and examples of designs with large orientational workspaces will be provided.

Note: The seminar will be presented at 11:00 a.m. in room PLT-2750.