Parameter identifier

A parameter identifier identifying one or more parameters of an n-order plant including n state variables, said plant being subject to a known disturbance represented by an m-order impulse train, said parameter identifier comprising:

• a model estimating the state variables and an output of the plant on the basis of identified parameters, and the input and output of the plant, said model comprising:
• a first delay circuit including serially connected (n+m) delay elements, each of which delays the output of the plant by one sample;
• first weighting means for obtaining (n+m) weighted linear combinations of the outputs of the delay elements of the first delay circuit, said first weighting means outputting the (n+m) weighted linear combinations as first state variables;
• first linear combination means for obtaining a linear combination of the first (n+m) state variables using the parameters identified as coefficients of that linear combination;
• a second delay circuit including serially connected (n+m) delay elements, each of which delays the input of the plant by one sample;
• second weighting means for obtaining (n+m) weighted linear combinations of the outputs of the delay elements of the second delay circuit, said second weighting means outputting the (n+m) weighted linear combinations as second state variables;
• second linear combination means for obtaining a linear combination of the second (n+m) state variables using the parameters identified as coefficients of that linear combination;
• and
• a first subtracter producing a difference between the output of the first linear combination means and the output of the second linear combination means;
• a subtracter calculating an error by subtracting the output of the plant from the estimated output of the plant produced from the model;
• a delay circuit delaying the state variables produced from the model by N samples, where N is an integer which is not less than 1 or more than (n+m+1);
• and
• a parameter adaptive mechanism for adjusting the parameters on the basis of the delayed state variables and the error.

A motor system comprising:

• a motor which is subject to a load disturbance;
• a parameter identifier identifying one or more parameters of the motor including n state variables, said motor being subject to a known disturbance represented by an m-order impulse train, said parameter identifier including
• a model estimating the state variables and an output of the plant on the basis of identified parameters, and the input and output of the plant;
• a subtracter calculating an error by subtracting the output of the plant from the estimated output of the plant produced from the model;
• a delay circuit delaying the state variables produced from the model by N samples, where N is an integer which is not less than 1 or more than (n+m+1);
• and
• a parameter adaptive mechanism for adjusting the parameters on the basis of the delayed state variables and the error;
• and
• a regulator producing a torque command from a speed command, the regulator modifying the torque command in accordance with the identified parameters.

A motor system comprising:

• a motor which is subject to a load disturbance, said motor having an elastic output shaft joined to a load, and the disturbance is applied to the load;
• a parameter identifier identifying one or more parameters of the motor including n state variables, said motor being subject to a known disturbance represented by an m-order impulse train, said parameter identifier including
• a model estimating the state variables and an output of the plant on the basis of identified parameters, and the input and output of the plant;
• a subtracter calculating an error by subtracting the output of the plant from the estimated output of the plant produced from the model;
• a delay circuit delaying the state variables produced from the model by N samples, where N is an integer equal to or less than (n+m+1);
• and
• a parameter adaptive mechanism for adjusting the parameters on the basis of the delayed state variables and the error;
• and
• a regulator producing a torque command from a speed command, the regulator modifying the torque command in accordance with the identified parameters.