Below we include some of the most salient and interesting related works. Section 2 of our paper provides additional context.

Related Work

Project Name	Author(s)	Approx. Date	Description
Some comparisons of serial-driven and parallel-driven manipulators	D. McCloy	1990	McCloy identified DeltaXY’s PRRRP mechanism in an exhaustive survey of the 32 possible 5-bar planar parallel-kinematic mechanisms (which reduces to 20 when you ignore mirrors).
GENIUS 500 Horizontal Machining Center	Cross Hüller GmbH	1998	An early commercialized version of the PRRRP mechanism, oriented vertically for horizontal machining. They operate the two links at a roughly 90-degree included angle to minimize non-linearity and improve stiffness. Importantly, they operate the mechanism between two upright structural posts, limiting lateral spatial efficiency.
Trijoint Horizontal Machining Center	Kovosvit MAS, a.s.	2003	Another commercial implementation similar to the GENIUS 500.
Kinematics, dynamics, and dimensional synthesis of a novel 2-DoF translational manipulator	Xin-Jun Liu, Qi-Ming Wang, and Jinsong Wang	2005	The simple 5-bar linkage has been replaced with two parallelograms meeting at a common plate, which consequently does not rotate. This allows the spindle to be oriented for vertical machining.
MIT-SS-1 Hybrid 5-Axis CNC milling machine	Seungkil Son, Taejung Kim, Sanjay E Sarma, and Alexander Slocum	2009	Rather than parallelograms to stabilize the spindle mount, three actuated links control its position and orientation within the 2D plane as part of a hybrid 5-axis milling machine. Unlike the other examples here, the MIT-SS-1 mechanism operates in a plane above the bearings, similarly to Cantilevered DeltaXY. This was done to minimize over-constraint, and realized LSE is about 33%.
DeltaXY	PavloG	2016	This is the first example we’ve seen of the PRRRP mechanism oriented horizontally, and also the first time the name DeltaXY appears. The LSE of the mechanism is limited by operating between the bearing rails. Interestingly, a stated design goal is to minimize the arm length, and consequently the shoulder separation is very narrow and mechanically disadvantageous. We surmise their goal was to minimize overall footprint rather than LSE.
Deltesian	Rob Stuart	2017	The parallelogram mechanism introduced by Liu et al. now makes it into the open-source 3D printer scene under the name “Deltesian.”
New Design and Prototype of Two Degrees-of-Freedom Planar Parallel Manipulator for Use in Creating an Infinite 3D Printer.	Miguel De La Melena and Shawn Duan	2024	Here the Deltesian mechanism is canted at an angle to realize an “infinite Z-belt” 3D printer.