A new grid-based fibre positioner concept with large patrol area, small pitch, and very good clustering capabilities

We present a new fibre positioner concept inspired by mechanisms used for minimally invasive surgery. The concept consists of a parallel mechanism that can be mass produced with laser cutting techniques and a tripod actuator mechanism for both positioning and maintaining focus. Advantages of the new design compared to existing positioner designs include very large patrol diameter per fibre (>30 mm) while allowing for very small pitch (~7 mm), very small minimal approaches between fibres, good clustering capabilities (20 fibres can reach a given sky location), easy control path and collision avoidance, robustness, mass producibility, the ability to accommodate non-telecentric and low-order polynomial focal surfaces, and the minimal bending and twisting of the fibre. A few design implementations will be presented.