kinematics; robotics; kinematical chains; Bennet’s mechanism; freedom of motion; robot- manipulators
There exist many examples of closed kinematical chains which have a freedom of motion, but there are very few systematical results in this direction. This paper is devoted to the systematical treatment of 4-parametric closed kinematical chains and we show that the so called Bennet’s mechanism is essentially the only 4-parametric closed kinematical chain which has the freedom of motion. According to  this question is connected with the problem of existence of asymptotic geodesic lines on robot-manipulators considered as submanifolds of a pseudo-Riemannian space. All computations were performed by the help of a formal manipulation system on a PC-computer.
 Karger A.: Classification of singular robot-manipulators. Submitted to Mech. Mach. Theory.
 Karger A.: Robot-manipulators as submanifolds
. Submitted to Mathematica Pannonica. Zbl 0793.53011