Circulair delta howto




http://www.cim.mcgill.ca/~paul/clavdelt.pdf
http://forums.trossenrobotics.com/tutorials/introduction-129/delta-robot-kinematics-3276/

http://www.mathsisfun.com/geometry/unit-circle.html

http://mhrg.if.uidaho.edu/papers/2011/HSI11_StanManSzepBal_PerfAnalDeltaRbt.pdf