Under operational condition of orbit scroll type compressor, a transient vibration and noise are apt to be generated due to collision between fixed and rotating orbit scroll surface with narrow clearance, which causes relative transient force. In order to reduce such vibration and noise, where and how the relative transient force is generated should be identified. By using a simple model, the relative transient force can be identified in time domain by inverse relative FRF matrix multiplied with response under operational condition. Then the method is applied to actual orbit scroll type compressor.
