Patent ID: 8018670
Filing Date: 2011-09-13
Classification: G11B

Abstract:
1. An evaluation apparatus for evaluating a transfer characteristic of a controlled object of a controller, the evaluation apparatus comprising: a response detection section that detects an input/output response of a control system, based on a signal detected in the control system, the control system including the controller and the controlled object; and a transfer characteristic calculating section that calculates the transfer characteristic of the controlled object, based at least on the input/output response, wherein the controller receives an error between a detection value of a controlled variable sampled at a predetermined sampling frequency and a desired value of the controlled variable, and outputs a manipulated variable of the controlled object at an output frequency higher than the sampling frequency, the controlled object is supplied with a disturbance added signal resulting from adding a disturbance signal having a frequency higher than a Nyquist frequency of the sampling frequency to a signal of the manipulated variable, the response detection section detects the input/output response of the control system in an aliasing frequency to which a frequency component of the disturbance signal is folded by sampling at the sampling frequency, based on input/output signals of the output frequency detected with a signal including the disturbance signal as an input and a signal including the response of the controlled object as an output, and the transfer characteristic calculating section calculates a transfer characteristic of the controlled object in the aliasing frequency, at least based on an input/output response in the aliasing frequency.