Motor control method and apparatus

A motor control apparatus for controlling an operating speed of a motor provided to move an object body, said motor control apparatus including a speed-signal generating portion operable to generate a speed signal corresponding to a moving speed of said object body, and a control-signal generating portion operable to generate a control signal for controlling the operating speed of said motor such that the moving speed of said object body represented by said speed signal coincides with a predetermined target value, said control-signal generating portion comprising:

• a filter operable to remove from said speed signal a component which has a frequency not lower than a predetermined threshold value;
• an error calculator operable to obtain a speed control error between a speed represented by an output of said filter and said target value;
• a proportional operator operable to obtain a proportional control value proportional to said speed control error;
• an integral operator operable to obtain an integral control value proportional to an integral of said speed control error;
• a differential operator operable to obtain a differential control value proportional to a derivative of said speed signal;
• and
• an arithmetic operator operable to generate said control signal on the basis of said proportional, integral and differential control values.

A motor control apparatus for controlling an operating speed of a motor provided to move a carriage carrying a printing head, said motor control apparatus including a speed-signal generating portion operable to generate a speed signal corresponding to a moving speed of said carriage, and a control-signal generating portion operable to generate a control signal for controlling the operating speed of said motor such that the moving speed of said carriage represented by said speed signal coincides with a predetermined target value, said control-signal generating portion comprising:

• a filter operable to remove from said speed signal at least a component corresponding to a cogging frequency of said motor;
• an error calculator operable to obtain a speed control error between a speed represented by an output of said filter and said target value;
• a proportional operator operable to obtain a proportional control value proportional to said speed control error;
• an integral operator operable to obtain an integral control value proportional to an integral of said speed control error;
• a differential operator operable to obtain a differential control value proportional to a derivative of said speed control error;
• and
• an arithmetic operator operable to generate said control signal on the basis of said proportional, integral and differential control values.