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US 5,404,418 AGranted
Closed-loop feedback control system having an adaptive filter
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTetsuaki Nagano
Life of this patent
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Abstract
A closed-loop feedback control system is disclosed for controlling an operation of a load. An actual operation signal is subtracted from a reference operation signal to produce a resultant signal which is used to control the operation of the load. A filter unit, such as a notch filter, operates to suppress any machine resonance frequencies found in the operation signal due to load fluctuations, machine variations, operating environment changes, deterioration with age, etc. A filter coefficient of the filter unit is adjusted so that any fluctuation in the resonance frequency can be suppressed effectively.
Claims7
A closed-loop feedback control system for controlling an operation of a load comprising:
- first subtracting means for subtracting an operation value from a command value, and for outputting a resultant signal as a control signal to control an operation of a load;
- filter means, operatively coupled to said first subtracting means, for passing frequency components of said control signal according to a set filter coefficient;
- and
- filter coefficient setting means, coupled to said filter means, for setting a filter coefficient and outputting said coefficient to said filter means, said filter coefficient setting means comprises:
- high-pass filter means for receiving said operation value and passing frequency components higher than a predetermined frequency;
- reference signal generating means for generating a reference signal having frequency components less than said predetermined frequency;
- adding means for adding said reference signal to said frequency components passed by said high-pass filter means, and for outputting a resultant signal from said adding;
- and
- adaptive filter means for receiving said reference signal and said resultant signal, and for selectively limiting passage of said frequency components passed by said high-pass filter means.
6 more elements
A motor speed controller comprising:
- deviation detecting means for outputting a deviation value between a speed command value and a speed detection value output by speed detecting means for detecting the speed of a mechanical system including a motor and a load driven by said motor;
- operating/amplifying means for operating on, amplifying and outputting said deviation value;
- torque controlling means for controlling the torque of said motor in accordance with a torque command value;
- a main filter, connected at a location between an output end of said speed detecting means and an input end of said torque controlling means and capable of limiting passage of a frequency component in accordance with a frequency component superimposed on said speed detection value, and outputting a result;
- and
- filter coefficient setting means, coupled to said main filter, for setting a filter coefficient of said main filter, said filter coefficient setting means comprises:
- reference signal generating means for outputting a reference signal including a frequency component lower than a predetermined frequency;
- a high-pass filter for receiving the speed detection value output by the speed detecting means and passing a frequency component higher than the predetermined frequency superimposed on said speed detection value;
- adding means for adding the reference signal output by said reference signal generating means and said frequency component having passed said high-pass filter;
- and
- an adaptive filter for receiving the output signal of said adding means and said reference signal, and producing a filter coefficient selectively limiting the passage of said frequency component, and outputting the coefficient to the main filter.
8 more elements
A motor speed controller comprising:
- deviation detecting means for outputting a deviation value between a speed command value and a speed detection value output by speed detecting means for detecting the speed of a mechanical system including a motor and a load driven by said motor;
- operating/amplifying means for operating on, amplifying and outputting said deviation value;
- torque controlling means for controlling the torque of said motor in accordance with a torque command value;
- a main filter, connected at a location between an output end of said speed detecting means and an input end of said torque controlling means and capable of limiting passage of a frequency component in accordance with a frequency component superimposed on said speed detection value, and outputting a result;
- and
- filter coefficient setting means, coupled to said main filter, for setting a filter coefficient of said main filter, said filter coefficient setting means comprising:
- reference signal generating means for receiving the speed command value and outputting a reference signal having a predetermined bandwidth;
- and
- an adaptive filter for receiving the reference signal output by said reference signal generating means and the speed detection value output by the speed detection means, operating on a filter coefficient for selectively limiting the passage of the frequency component higher than the predetermined frequency superimposed on said speed detection value, and outputting the result to the main filter.
6 more elements
Dependencies are inferred from the claim text.