Synchronous position control apparatus and method

A synchronous position control apparatus comprising:

• an acceleration command value generator which generates target acceleration command values for a plurality of axes to be controlled;
• compensators for the respective axes which convert the respective target acceleration command values in accordance with predetermined transfer functions, and output the converted values as converted acceleration command values;
• integrators for the respective axes which integrate the respective converted acceleration command values twice, and output the integrated values as position command values;
• correctors for the respective axes which perform predetermined compensation for the respective converted acceleration command values, and output the compensated values as feedforward signals;
• and
• position controllers for performing control based on position feedback control for the respective axes on the basis of the respective position command values and the feedforward signals,
• wherein characteristics of the transfer functions are set to be substantially the same high-frequency cutoff characteristics for the respective axes, and the cutoff frequency of the transfer function is set to a smaller value than a servo band in any one position controller.

A synchronous position control method comprising:

• an acceleration command value generation step of generating target acceleration command values for a plurality of axes to be controlled;
• a conversion step of converting the respective target acceleration command values in accordance with predetermined transfer functions for the respective axes, and outputting the converted values as converted acceleration command values;
• an integral step of integrating the respective converted acceleration command values twice, and outputting the integrated values as position command values for the respective axes;
• a compensation step of performing predetermined compensation for the respective converted acceleration command values, and outputting the compensated values as feedforward signals for the respective axes;
• and
• a position control step of performing control based on position feedback control for the respective axes on the basis of the position command values and the feedforward signals,
• wherein characteristics of the transfer functions are set to substantially the same high-frequency cutoff characteristics for the respective axes, and the cutoff frequency of the transfer function is set to a smaller value than a servo band in said any position feedback control.

A position control apparatus comprising:

• a first control loop for performing a first position feedback control for a first control axis;
• a second control loop for performing a second position feedback control for a second control axis;
• and
• plural prefilters set outside the first and second control loops so that transfer characteristics of the first and second control axes are substantially the same.

A position control method comprising the steps of:

• performing a first position feedback control for a first control axis by a first control loop;
• performing a second position feedback control for a second control axis by a second control loop;
• and
• controlling transfer characteristics of the first and second control axes to be substantially the same by plural prefilters set outside the first and second control loops.