This paper is a continuation of the previous work by means of numeric and experiment. The coupling characteristics of two exciters are described briefly. Numerical analyses corresponding to the previous theoretical results are given. Here the response curve of the frequency–amplitude reflects distinctly the hardening nonlinear characteristic of the system. The key factors of implementing synchronization and ensuring stability are weighed up by the possibilities of synchronization and stability, respectively. Three types of phase relationships of the system in the steady state are discussed, as well as the load torque of two motors. It is shown that the greater and stable response of the relative motion can be achieved in the sub-resonant or near sub-resonant state, for two identical exciters. In this case the phase difference of two exciters is stabilized in the vicinity of zero, and the relative motion of two rigid frames is the opposite phase. The above facts are exactly the desires in engineering. An experiment is carried out, and several satisfactory experimental results are obtained for different resonant types, which are in approximate or good agreement with the numerical results. By comparison with theory, numeric and experiment, the feasibility and validity of the theory method used are examined and verified.