This paper describes an electromechanical fatigue stand which was developed in Opole University of Technology in a research and development project financed by the Polish government. It shows the principle operation of the strength testing machine and functionality of its electronic and software control system. Different types of possible fatigue tests were presented, i.e. uniaxial and biaxial (bending and torsion), cyclic and polyharmonic. Equations were discussed concerning the strain density energy parameter in bending and torsional axes. The theory was implemented in LabVIEW software in the control system of the machine. The main aim of this paper is the presentation of fatigue of a machine control system for material tests under polyharmonic bending and torsion based on the recently defined energy fatigue damage parameter.