ABB has just launched a new type of parallel kinematic machine (PKM), dubbed the FlexPLP (Flexible Principle Locator
Points), designed for flexible fixturing tasks.
The FlexPLP is intended to replace fixed locator points which are used to define the geometry of car body parts
during framing and welding with numerically controlled locator points. A parallel kinematic machine called
Deltapod was developed to freely position the locator pins in space.
Fig. 1: The FlexPLP in action
The Deltapod represents a combination of well-known Delta and hexapod principles. It consists of three pairs of
parallelly arranged electrical cylinders, forming the legs of the machine. By arranging the leg pairs in tilted
fashion, foot print of the machine could be minimized, while keeping the other key machine parameters constant. The
result is a very compact but powerful machine that can carry payloads exceeding four times its own mass.
The first application of the new machine is part fixturing in a flexible automotive bodyshop. Four or more FlexPLPs
are arranged on a linear track, fixturing car underbodies and serving welding stations as flexible shuttles, adapting
to each car model. The shuttles pick up unfinished car bodies form one station and transport them to the next station
where they are received by stationary Cartesian flexible positioners. This new principle, part of ABB's FlexLean
concept, allows to eliminate the large number of fixed pallets used for transport of car bodies through the factory
today, and allows for multi-model production.
Since this application requires only three degrees of freedom for each machine, a hexapod with six motors would not
reach the cost target. Therefore, ABB invented and patented a mechanical coupling between the cylinders, which allows
to drive a pair of cylinders with a single motor. One Deltapod requires only three motors, just like a Delta robot.
This reduces the cost on the amplifier and controller side ABB's robot controller IRC5 is able to control
twelve of these three-axis machines.
Fig. 2: CAD model of the FlexPLP