In this paper, a controlled oscillation using the levitation mass method (LMM) for material with nonlinear viscoelasticity is proposed. Since LMM is a very accurate and efficient method of measuring a varying force, it has a possibility to apply to the material tester. For LMM, system identification process is introduced to grasp the nonlinear components of the restoring force. The process consists of the experiment and frequency analysis for higher modes which originate for the nonlinear restoring force. The input signal is then derived based on the identification results. By adding the proposed identification process to LMM, the arbitrary waveform of the force can be investigated even in the open-loop excitation. The effectiveness of the proposed oscillation method is verified through the LMM-based experiments.