Diagnostic method and diagnostic apparatus

A diagnostic apparatus comprising:

• a controller configured to:
• calculate an impulse response based on an acceleration command and measured acceleration of a mechanical structure, the acceleration command being generated based on a log swept sine (LOGSS) signal, the measured acceleration being measured when a position of the mechanical structure to be diagnosed is changed based on the acceleration command, the impulse response including a first section in which a linear characteristic of the mechanical structure appears and a second section in which a nonlinear characteristic of the mechanical structure appears, the first section being separated from the second section;
• analyze the linear characteristic of the mechanical structure from the first section of the impulse response;
• analyze the nonlinear characteristic of the mechanical structure from the second section of the impulse response;
• and
• diagnose the mechanical structure based on analysis results of the linear characteristic and the nonlinear characteristic of the mechanical structure.

A non-transitory computer readable medium including computer executable instructions, wherein the instructions, when executed by a processor, cause the processor to perform a method comprising:

• controlling a drive unit based on an acceleration command to change a position of a mechanical structure to be diagnosed, the acceleration command being generated based on a log swept sine (LOGSS) signal;
• calculating an impulse response based on the acceleration command and measured acceleration of the mechanical structure, the measured acceleration being measured by an accelerometer, the impulse response including a first section in which a linear characteristic of the mechanical structure appears and a second section in which a nonlinear characteristic of the mechanical structure appears, the first section being separated from the second section;
• analyzing the linear characteristic of the mechanical structure from the first section of the impulse response of the mechanical structure;
• analyzing the nonlinear characteristic of the mechanical structure from the second section of the impulse response;
• and
• diagnosing the mechanical structure based on analysis results of the linear characteristic and the nonlinear characteristic of the mechanical structure.