SUMMARYThis paper discusses one problem of robot dynamics rarely mentioned in papers relevent to this field. It is the problem of torsional effects in torque transmissions (reducers, shafts, transmission chains, etc.). The problem is significant since oscillations can appear to be due to these effects. The complete dynamic model, which includes these effects, is derived and the possible simplifications considered. The position of feedback transducers is discussed since it appears as an important problem when it is intended to minimize the influence of these elastic vibrations. The discussion is based on eigenvalues and simulation results.
