For some time I’ve been wanting to build a parallel kinematics machine tool and I’ve done my homework, but nothing replaces getting your hands dirty.
LNG1 is coming along slowly but its dual-drive X axis has been operational for some time, so I got the idea of using it as the basis for a simple two-axis PKM test platform. It was only a matter of cobbling together two parallelograms using DIY store hinges and some slotted extrusion beams. Here’s the result :
I rather like the way this machine moves. I’m thinking of using such a design on small CNC mills and lathes. This being only a two-axis PKM, the forward kinematics formulas are very simple, which will allow me to concentrate on their actual real-time implementation.
The servomotors used in this test are two EvoDrive ST-23’s from EvaRobotics. This specific type of fully-integrated servo isn’t optimized for CNC applications but it is very handy if you need to position something using simple commands through RS485, RS232 or USB.
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